-
MESO: Severe potential
From
Weather Alert@21:1/175 to
All on Mon Jan 25 23:13:00 2021
ACUS11 KWNS 252250
SWOMCD
SPC MCD 252249
ALZ000-TNZ000-MSZ000-260015-
Mesoscale Discussion 0033
NWS Storm Prediction Center Norman OK
0449 PM CST Mon Jan 25 2021
Areas affected...Northern/Central Mississippi...Western/Middle Tennessee...Northwest Alabama
Concerning...Severe potential...Watch possible
Valid 252249Z - 260015Z
Probability of Watch Issuance...60 percent
SUMMARY...Scattered strong thunderstorms are expected across the
Mid-South into Middle TN this evening. Some risk for tornadoes may
necessitate a watch in the next couple of hours.
DISCUSSION...Strong mid-level short-wave trough is ejecting across
the central Plains this evening. The more appreciable height falls
will spread across the Mid-MS into the OH Valley region. Along the
southern fringe of this stronger large-scale forcing, robust
convection has recently developed across portions of western TN
where surface dew points have risen into the mid 60s with surface
temperatures in the lower 70s. This activity should spread
east-northeast along a corridor that is destabilizing just south of
a well-defined warm front. Ample shear/buoyancy exist for supercells
(possibly tornadic supercell ongoing over Fayette County TN) and
there is increasing concern/confidence that other organized
longer-lived storms may develop.
Farther south along the Pacific front, showers are gradually
deepening from northwest MS into northeast LA. Some lightning is
noted with the stronger updrafts but activity has struggled to
organize. It's not entirely clear how many organized supercells
can/will develop along this zone, but shear/buoyancy do favor some
tornado threat. Tornado watch may be warranted for this activity in
the next couple of hours.
..Darrow/Thompson.. 01/25/2021
ATTN...WFO...OHX...BMX...HUN...MEG...JAN...
LAT...LON 33159055 35478893 35888710 35008651 33568819 32718919
33159055
#
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Sat Feb 13 15:12:00 2021
ACUS11 KWNS 131459
SWOMCD
SPC MCD 131458
FLZ000-131630-
Mesoscale Discussion 0075
NWS Storm Prediction Center Norman OK
0858 AM CST Sat Feb 13 2021
Areas affected...portions of central Florida
Concerning...Severe potential...Watch unlikely
Valid 131458Z - 131630Z
Probability of Watch Issuance...20 percent
SUMMARY...A band of thunderstorms moving across central Florida at
this time may pose risk for a locally stronger/damaging wind gust or
two, and possibly a brief tornado, before moving offshore through
midday.
DISCUSSION...Latest radar loop shows a band of locally strong
thunderstorms moving across central Florida, just south of a cold
front extending from just north of Daytona to just south of Cross
City. South of the front, dewpoints in the upper 60s to low 70s but
rather weak lapse rates above 700mb are yielding only modest
instability (around 500 J/kg mixed-layer CAPE ahead of the
convective band). However, offsetting the modest instability, shear
across the region is sufficient for organized/stronger updrafts,
with flow veering weakly and increasing with height to 50 kt from
the southwest at mid levels. As such, and given increasingly linear
storm mode, gusty winds associated with small bowing segments or
areas of weak mesolow-type circulations can be expected, along with
risk for minor damage. Risk is expected to remain sufficiently
limited in time/intensity/area to preclude any need for WW issuance.
..Goss/Grams.. 02/13/2021
ATTN...WFO...MLB...TBW...JAX...
LAT...LON 28218048 27658150 27548203 28318168 28988163 29388129
29008075 28218048
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Sun Feb 28 00:24:00 2021
ACUS11 KWNS 280007
SWOMCD
SPC MCD 280006
TNZ000-ALZ000-MSZ000-280230-
Mesoscale Discussion 0132
NWS Storm Prediction Center Norman OK
0606 PM CST Sat Feb 27 2021
Areas affected...Tennessee Valley
Concerning...Severe potential...Watch unlikely
Valid 280006Z - 280230Z
Probability of Watch Issuance...20 percent
SUMMARY...A threat for strong wind gusts and hail is expected across
parts of western and middle Tennessee over the next few hours. Due
to the marginal nature of the threat, weather watch issuance is not
expected.
DISCUSSION...The latest surface analysis shows a quasi-stationary
front located from far northern Mississippi extending
east-northeastward across southern Tennessee. A corridor of
maximized low-level moisture is analyzed to the south of the front
where surface dewpoints are in the lower to mid 60s F. According to
the RAP, MLCAPE has increased into the 250 to 750 J/kg range along
this tongue of low-level moisture. Thunderstorms have recently
developed into western Tennessee along the northern edge of the
instability corridor. The storms are being supported by a warm
advection regime. The storms should continue to spread
east-northeastward across middle Tennessee over the next few hours.
The weak instability combined with 60-65 kt of deep-layer shear,
evident on the Nashville WSR-88D VWP will support a marginal wind
damage and hail threat. However, the threat is not expected to be
sufficient to warrant weather watch issuance.
..Broyles/Grams.. 02/28/2021
ATTN...WFO...OHX...HUN...MEG...
LAT...LON 34958763 34998881 35138935 35368956 35798939 36128888
36528757 36478644 36188595 35478583 35008642 34958763
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Sat Mar 13 09:51:00 2021
ACUS11 KWNS 131337
SWOMCD
SPC MCD 131336
OKZ000-TXZ000-NMZ000-131600-
Mesoscale Discussion 0162
NWS Storm Prediction Center Norman OK
0736 AM CST Sat Mar 13 2021
Areas affected...Portions of northeastern NM and the western TX/OK
Panhandles
Concerning...Severe potential...Watch unlikely
Valid 131336Z - 131600Z
Probability of Watch Issuance...20 percent
SUMMARY...An isolated threat for large hail may develop this
morning. Watch issuance appears unlikely at this time.
DISCUSSION...Pronounced ascent preceding a mid/upper-level jet has
encouraged the development of elevated thunderstorms across parts of east-central into northeastern NM this morning. This activity is
occurring on the northern fringe returning boundary-layer moisture,
with latest mesoanalysis showing an elevated instability gradient
extending southwest to northeast across this area. 12Z observed
soundings from both ABQ and AMA show steep mid-level lapse rates,
which should support MUCAPE generally in the 400-750 J/kg range this
morning to the north of a surface front. Very strong effective bulk
shear of 50-60+ kt will likely support supercell structures and an
isolated large hail risk as these storms move quickly northeastward.
Current expectations are for these storms to remain largely elevated
to the north of the surface front through the morning. The overall
hail threat should remain fairly limited due to the marginal
thermodynamic environment, and watch issuance appears unlikely at
this time.
..Gleason/Thompson.. 03/13/2021
ATTN...WFO...AMA...ABQ...
LAT...LON 34980421 35400432 36280375 36950303 36970202 36820166
36350162 35250217 35010245 34830304 34780382 34980421
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Thu Mar 25 15:56:00 2021
ACUS11 KWNS 251930
SWOMCD
SPC MCD 251929
TNZ000-ALZ000-MSZ000-252130-
Mesoscale Discussion 0257
NWS Storm Prediction Center Norman OK
0229 PM CDT Thu Mar 25 2021
Areas affected...far northern Mississippi into Middle Tennessee
Concerning...Severe potential...Tornado Watch likely
Valid 251929Z - 252130Z
Probability of Watch Issuance...80 percent
SUMMARY...The threat of severe storms including tornadoes will
increase by late afternoon into Middle Tennessee and persist through
the evening. A watch may be issued by 21Z.
DISCUSSION...Surface analysis currently shows a warm front into far southwestern TN extending east/southeast into northern AL.
Meanwhile, another warm front extended from the developing surface
low from southern IL into central KY.
In between these two fronts, gradual warming is taking place, with
temperatures now into the low 70s F. MUCAPE currently remains below
1000 J/kg as a result of dewpoints near 60 F.
Strengthening 850 mb winds out of the southwest later today should
aid moisture advection out of MS into Middle TN, with areas of
heating helping to destabilize as well. Shear will become
increasingly favorable for tornadic supercells in the 21-03Z time
frame, and a few tornadoes are anticipated as the mid 60s F
dewpoints arrive later today. With the more unstable air in place,
effective SRH may reach 400-500 m2/s2.
..Jewell/Hart.. 03/25/2021
ATTN...WFO...OHX...HUN...MEG...
LAT...LON 35048892 35238887 35668872 36178799 36478647 36318583
36008560 35548590 35368661 35378741 35278780 34998804
34718875 34798891 35048892
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Thu Mar 25 15:57:00 2021
ACUS11 KWNS 251933
SWOMCD
SPC MCD 251933
INZ000-KYZ000-TNZ000-ILZ000-MOZ000-252130-
Mesoscale Discussion 0258
NWS Storm Prediction Center Norman OK
0233 PM CDT Thu Mar 25 2021
Areas affected...The mid-Mississippi River Valley and lower Ohio
River Valley Region
Concerning...Severe potential...Tornado Watch likely
Valid 251933Z - 252130Z
Probability of Watch Issuance...80 percent
SUMMARY...A tornado watch is likely in the coming hours as a surface
low and associated warm front continue to lift northward through the
late afternoon.
DISCUSSION...Surface observations over the past couple of hours have
shown 2-3 mb surface pressure falls over northeast AR into the lower
OH River Valley region. The surface low located over northeast AR
continues to consolidate and is expected to deepen further as it
lifts to the north/northeast. As this occurs, an associated surface
warm front will lift to the north and allow a higher theta-e air
mass (noted by temperatures and dewpoints in the 60s) to overspread
the mid-MS River Valley and lower OH River Valley regions and allow
MLCAPE to increase into the 500-1000 J/kg range. Storms are forecast
to develop along the surface warm front and surface trough in the
vicinity of the low, and southwesterly 60-70 knots of effective bulk
shear will help support discrete to semi-discrete storm modes. Along
with a hail/wind threat, backed low-level winds within the open warm
sector will support ESRH values on the order of 300 m2/s2 and a
tornado threat with any discrete convection that can develop. Recent
guidance suggests storm initiation within this region may occur
within the 22-00 UTC time frame. A tornado watch will likely be
needed in the coming hours to address this concern.
..Moore/Hart.. 03/25/2021
ATTN...WFO...LMK...OHX...IND...PAH...ILX...MEG...LSX...
LAT...LON 36498774 36148863 35988936 36238974 36718989 37438983
38008958 38438912 38778824 38788726 38348672 37528679
37008706 36498774
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Wed Mar 31 15:08:00 2021
ACUS11 KWNS 311823
SWOMCD
SPC MCD 311822
NCZ000-VAZ000-SCZ000-312015-
Mesoscale Discussion 0309
NWS Storm Prediction Center Norman OK
0122 PM CDT Wed Mar 31 2021
Areas affected...Portions of South/North Carolina into southeast
Virginia
Concerning...Severe potential...Watch possible
Valid 311822Z - 312015Z
Probability of Watch Issuance...40 percent
SUMMARY...Strong to severe storms along a cold front may pose a risk
for damaging winds and a brief tornado or two late this afternoon
and evening. A severe thunderstorm watch could be needed later this
afternoon or early this evening if storms are able to organize.
DISCUSSION...1800Z surface obs showed a broad plume of 60s F
dewpoints stretching from the Carolina Piedmont northward into
eastern Virginia. To the west, a slow moving cold front associated
with low pressure across the Northeast was located along the spine
of the Appalachians. A large band of cloud debris and stratiform
precipitation are ongoing along and east of the front. Clear skies
along and east of the differential heating axis have allowed
temperatures to warm into the upper 70s to low 80s F across the
eastern Carolinas and Virginia. While mid-level lapse rates remain
poor (5-6 C/km), modest destabilization is occurring, and should
continue through the afternoon. MLCAPE of 500-1000 J/kg is expected
from central South Carolina northward into southern Virginia. This
buoyancy should be sufficient to support thunderstorm development
along the eastern edge of the differential heating axis this
afternoon. The most likely corridor for severe weather appears to be
across southern North Carolina and east-central South Carolina where
greater heating/destabilization is occurring. Deep-layer shear of
30-40 kts oriented parallel to the zone of initiation should favor a quasi-linear mode with the primary risk being damaging wind gusts.
Given the linear storm mode and limited low-level shear, the tornado
risk is likely low. However, a brief tornado or two may occur with
any stronger QLCS/embedded supercell segments and localized areas of
backed surface flow. Trends will be monitored for a possible severe thunderstorm watch to cover the risk of damaging wind gusts/a brief
tornado later this afternoon into early this evening.
..Lyons/Grams.. 03/31/2021
ATTN...WFO...AKQ...MHX...RAH...ILM...RNK...CAE...GSP...
LAT...LON 36777871 37107815 37147742 37077705 36897660 36717651
36377634 35937646 35137702 34547766 33967873 33767921
33378061 33278098 33338147 33648196 34218200 34348183
34778124 35478020 36147942 36777871
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Sat Apr 10 10:27:00 2021
ACUS11 KWNS 101359
SWOMCD
SPC MCD 101358
FLZ000-GAZ000-101530-
Mesoscale Discussion 0360
NWS Storm Prediction Center Norman OK
0858 AM CDT Sat Apr 10 2021
Areas affected...the Florida Panhandle and parts of far southern
Georgia
Concerning...Severe potential...Watch likely
Valid 101358Z - 101530Z
Probability of Watch Issuance...95 percent
SUMMARY...Severe risk continues across the portions of WW 89 that
remain in effect, with some risk evident eastward across the
remainder of the Florida Panhandle. A new WW will likely be issued.
DISCUSSION...Latest radar loop shows the northeastern portion of a
northern Gulf of Mexico band of storms now crossing central portions
of the Florida Peninsula west of Tallahassee. Gusty/damaging wind
risk remains apparent -- per WSR-88D imagery, where outflow in
excess of 50 kt is indicated just off the surface across parts of
Washington and Bay counties.
Very limited heating of the relatively moist airmass just downstream
is supporting mixed-layer CAPE values of 500 to 1000 J/kg. While a
more stable/drier airmass exists into the northern Florida
Peninsula, it appears at this time that a sufficiently unstable
environment downstream into the Big Bend region will support a
continued eastward advance of storms. Locally damaging winds will
remain the primary severe risk, though a QLCS-type tornado or two
will remain possible. With storms expected to move out of the
existing watch within the next hour, a new WW will be issued
shortly.
..Goss/Thompson.. 04/10/2021
ATTN...WFO...JAX...TAE...
LAT...LON 30548604 30998546 30878418 30938356 30608328 29748299
29198324 29498512 29798596 30548604
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Sat Apr 10 18:19:00 2021
ACUS11 KWNS 102135
SWOMCD
SPC MCD 102135
SCZ000-NCZ000-102330-
Mesoscale Discussion 0363
NWS Storm Prediction Center Norman OK
0435 PM CDT Sat Apr 10 2021
Areas affected...parts of South Carolina into North Carolina
Concerning...Severe potential...Watch unlikely
Valid 102135Z - 102330Z
Probability of Watch Issuance...20 percent
SUMMARY...An uptick in storm coverage and intensity is possible over
the next few hours, but the risk appears too low for watch
consideration.
DISCUSSION...An embedded lead wave is currently moving across
northern GA and into the western Carolinas, with a concentration of
shallow convection along the GA/SC border. Surface analysis shows
temperatures in the 70s F ahead of this feature, with low 60s F
dewpoints resulting in around 500 J/kg SBCAPE. Little lightning has
been noted as of late, due to relatively warm midlevel temperatures
and thus shallow nature of the convection.
Effective SRH near 200 m2/s2 exists over the western Carolinas,
along with 50 kt effective bulk shear. This may support weakly
rotating storms over the next few hours, before the boundary layer
stabilizes.
..Jewell.. 04/10/2021
ATTN...WFO...RAH...ILM...CAE...GSP...
LAT...LON 34378009 33968062 33768118 33828169 33998235 34478263
35068241 35578190 35808127 35928063 35778000 35317973
34787992 34378009
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Wed Apr 14 14:00:00 2021
ACUS11 KWNS 141744
SWOMCD
SPC MCD 141743
TXZ000-141945-
Mesoscale Discussion 0382
NWS Storm Prediction Center Norman OK
1243 PM CDT Wed Apr 14 2021
Areas affected...portions of the Texas Coastal Plain
Concerning...Severe potential...Watch possible
Valid 141743Z - 141945Z
Probability of Watch Issuance...40 percent
SUMMARY...Storm development over the next couple of hours will be
accompanied by some increase in risk for large hail and locally
strong/damaging wind gusts through this afternoon. A WW may be
required.
DISCUSSION...Latest surface analysis shows a cold front across
western portions of the Texas Coastal Plain/eastern fringes of the
Hill Country, and then westward into the Edwards Plateau.
Meanwhile, a sea-breeze boundary has pushed into coastal counties,
with high theta-e marine air along and east of this boundary.
Though capping (near 700 mb) remains established across the area,
continued heating/mixing of the boundary layer will weaken the cap
locally -- particularly near the aforementioned surface boundaries
where ascent is locally maximized. With steep lapse rates overlying
this region above the capping layer, the destabilizing environment
-- represented by mixed-layer CAPE values now in excess of 2500 J/kg
across the region per RUC-based objective analyses -- combined with
the weakening cap will support local/robust updraft development.
While deep-layer shear is not excessive, partially owing to modest
low-level flow, ample (around 30 kt) mid-level west-southwesterlies
are contributing to shear sufficient for multicell organization, and
even some mid-level updraft rotation. As such, potential for hail
and/or locally strong outflow winds will be possible with a few of
the strongest storms. We will continue to monitor development, for
signs that convective development/coverage may warrant WW issuance.
..Goss/Thompson.. 04/14/2021
ATTN...WFO...HGX...CRP...EWX...
LAT...LON 29279811 29559761 29829683 29909598 30189492 29659475
28749616 28169709 28299783 28449828 28839839 29279811
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Sat Apr 24 19:53:00 2021
ACUS11 KWNS 242347
SWOMCD
SPC MCD 242347
GAZ000-250145-
Mesoscale Discussion 0429
NWS Storm Prediction Center Norman OK
0647 PM CDT Sat Apr 24 2021
Areas affected...Parts of southeastern Georgia
Concerning...Severe potential...Watch possible
Valid 242347Z - 250145Z
Probability of Watch Issuance...40 percent
SUMMARY...Potential for strong surface gusts may remain somewhat
marginal and/or isolated in the near term, but this could increase
as upstream storms spread into the region later this evening.
DISCUSSION...A 40-50 kt southwesterly 850 mb jet is impinging on the southwestern flank of a convectively reinforced surface cold pool,
across much of southern/eastern Georgia. As this enhances warm
advection and associated lift of moist and moderately unstable air
along the associated quasi-stationary baroclinic zone, one small,
but organized, cluster of storms has emerged and is progressing
north through northeast of the Waycross, GA area. This appears near
the core of the most stable boundary layer air, and potential for
damaging surface gusts to reach the surface remains unclear as the
cluster continues into coastal areas south of Savannah, GA through
01Z.
However, as the southerly low-level jet noses northeastward this
evening, ahead of the vigorous approaching mid-level short wave
trough, it appears that the stable boundary-layer may undergo
considerable modification. If another cluster of storms is able to
organize upstream, near the intersection of the outflow reinforced
boundary and a pre-cold frontal wind shift across southeastern
Alabama into southwestern Georgia, then there may be increasing
potential for damaging wind gusts as it overspreads a similar track
as the preceding system later this evening.
..Kerr/Thompson.. 04/24/2021
ATTN...WFO...CHS...JAX...FFC...TAE...
LAT...LON 31858293 31938230 32108154 31938090 31108134 30788313
31128365 31858293
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Mon May 3 18:36:00 2021
ACUS11 KWNS 032152
SWOMCD
SPC MCD 032151
ILZ000-MOZ000-ARZ000-032315-
Mesoscale Discussion 0501
NWS Storm Prediction Center Norman OK
0451 PM CDT Mon May 03 2021
Areas affected...portions of southern Missouri and far southwestern
Illinois
Concerning...Severe potential...Watch possible
Valid 032151Z - 032315Z
Probability of Watch Issuance...40 percent
SUMMARY...An isolated threat for damaging winds and hail is possible
with developing thunderstorms near Springfield, MO. A watch is
possible but high uncertainty remains.
DISCUSSION...Afternoon water vapor imagery showed a small shortwave
trough/ MCV moving across a stalled cold front along the Mississippi
River Valley into the Midwest. Heating along the front has eroded
the majority of MLCINH across southwestern Missouri. SPC
mesoanalysis indicates surface dewpoints in the low to middle 60s F
and lapse mid-level lapse rates near 8 C/km are supporting 1500-2500
J/kg of MLCAPE. Flow aloft is not overly strong, but mid-level flow
around 30 kts maybe be sufficient to support marginal supercells.
Latest WOFS guidance indicates a moderate probability (50-70%) that
the ongoing storms along the I-44 corridor will reach severe
criteria over the next couple of hours. With veered low-level winds
decreasing effective hodograph size, the primary severe threats will
be large hail and damaging wind gusts.
Considerable uncertainty remains on the coverage, longevity, and
severity of storms as they translate northeastward over the next
couple of hours. The favorable thermodynamics and marginal shear
parameter space suggest some severe threat may materialize.
Conditions will be monitored for a possible severe thunderstorm
watch.
..Lyons/Thompson.. 05/03/2021
ATTN...WFO...PAH...LSX...SGF...TSA...
LAT...LON 36719371 37379316 37889265 38459207 38759107 38839019
38348969 37638949 36928994 36759100 36539278 36469392
36719371
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Wed May 5 15:36:00 2021
ACUS11 KWNS 051929
SWOMCD
SPC MCD 051929
OKZ000-KSZ000-TXZ000-COZ000-052200-
Mesoscale Discussion 0545
NWS Storm Prediction Center Norman OK
0229 PM CDT Wed May 05 2021
Areas affected...Portions of southwest Kansas...extreme southeast Colorado...Oklahoma Panhandle
Concerning...Severe potential...Watch unlikely
Valid 051929Z - 052200Z
Probability of Watch Issuance...20 percent
SUMMARY...Scattered strong storms are expected through the
afternoon. Damaging gusts and perhaps some marginally severe hail
may accompany the stronger storms. A WW issuance is not currently
anticipated.
DISCUSSION...Convective initiation is underway along a surface cold
front across western Kansas into eastern Colorado, just south of a
CBK-GLD-ITR line, and is gradually propagating southeast. Convection
will continue to gradually deepen and intensify with continued
strong diurnal heating and associated boundary-layer mixing.
Deep-layer steep lapse rates are in place, with the latest RAP PFCs
suggesting boundary-layer mixing past 700 mb. 8-9 C/km lapse rates
are present within the lowest 2 km, overspread by 7.5-8.5 C/km lapse
rates in the mid levels. Relatively stronger flow aloft (i.e. 50+
kts) is contained roughly above 500 mb. Still, the presence of a
deep, dry sub-cloud layer will promote enough evaporative cooling
for efficient downward momentum transport of the mid-level flow with
any of the stronger storm cores that can develop. A brief instance
or two marginally severe hail is also possible given the steep
mid-level lapse rates.
Nonetheless, the severe threat is expected to remain brief and
sparse overall. A WW issuance is not currently expected.
..Squitieri/Grams.. 05/05/2021
ATTN...WFO...OUN...DDC...GLD...AMA...PUB...
LAT...LON 36470180 36890216 37340219 37830203 38290181 38510147
38720086 38650036 38450003 37959977 37389973 36889982
36639999 36500021 36470180
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Sun May 9 15:57:00 2021
ACUS11 KWNS 091832
SWOMCD
SPC MCD 091831
TXZ000-NMZ000-COZ000-092100-
Mesoscale Discussion 0569
NWS Storm Prediction Center Norman OK
0131 PM CDT Sun May 09 2021
Areas affected...Northeast New Mexico...far southeast Colorado...and
the far western Texas Panhandle
Concerning...Severe potential...Watch unlikely
Valid 091831Z - 092100Z
Probability of Watch Issuance...20 percent
SUMMARY...Thunderstorms developing across northeast New Mexico and
far southeast Colorado over the next few hours will pose a threat
for damaging winds and perhaps isolated hail. This threat will
remain isolated, and a watch is not expected.
DISCUSSION...A deepening cluster of cumulus within a post
cold-frontal upslope flow regime across north/northeastern NM is
noted in recent GOES imagery. A few lightning strikes have been
noted in the past hour with transient convective cells, hinting that
more robust convection is possible in the next 1-2 hours. Across the
high Plains to the east, temperatures are gradually warming into the
low 60s amid partly cloudy skies. Cool temperatures aloft atop the
warming boundary-layer are steepening low-level lapse rates to 7-9
C/km, and this trend should continue with eastward extent through
the late afternoon. Although instability will remain somewhat
limited due to minimal low-level moisture (only around 500 J/kg
MLCAPE is expected), 30-45 knot effective bulk shear magnitudes may
support some storm organization and an isolated hail threat adjacent
to the higher terrain. Given the well-mixed boundary layer, strong
downburst winds appear to be the more likely hazard. In general, the
localized forcing for ascent and limited instability will likely
result in only a few strong to severe storms that may propagate as
far east as the NM/TX border by early evening. The overall severe
threat is expected to remain isolated, precluding the need for a
watch.
..Moore/Thompson.. 05/09/2021
ATTN...WFO...LUB...AMA...PUB...ABQ...
LAT...LON 34710551 35170586 35680611 36390582 36940551 37290510
37470460 37450410 37130357 36620325 35960290 34930287
34320307 34300453 34710551
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Tue May 11 15:38:00 2021
ACUS11 KWNS 111823
SWOMCD
SPC MCD 111822
TXZ000-112045-
Mesoscale Discussion 0592
NWS Storm Prediction Center Norman OK
0122 PM CDT Tue May 11 2021
Areas affected...Parts of the lower Pecos into lower Rio Grande
Valley vicinity
Concerning...Severe potential...Watch possible
Valid 111822Z - 112045Z
Probability of Watch Issuance...40 percent
SUMMARY...Intense thunderstorms are initiating, mainly across the
higher terrain of Coahuila, but may be slow to develop eastward.
Once a propagation into lower elevations commences, activity
probably will pose a risk for large hail and strong wind gusts
across and east of the Rio Grande River. It is possible that this
might not occur until after 4-5 PM CDt.
DISCUSSION...Thunderstorms are initiating along the higher terrain,
as far north as the lower Pecos Valley, but generally southeast
through south of the Texas Big Bend, across Coahuila. Mid 70s
surface dew points have advected west of the Rio Grande, toward the
higher terrain, contributing to large CAPE in excess of 3000 J/kg,
in the presence of steep lower/mid tropospheric.
Given somewhat modest (20-30 kt) west-southwesterly ambient
deep-layer mean flow, and lingering inhibition associated with
elevated mixed-layer air to the east of the higher terrain, activity
might be slow to develop off the higher terrain. However, given the
the number of storms, merging convection and consolidating outflows
probably will contribute to upscale growth that should eventually
surge off the higher terrain, into and across the Rio Grande Valley
later this afternoon. It remains unclear just how this might
evolve, but there appears strong enough shear beneath the
subtropical jet, across and south of the Del Rio vicinity, to
support the evolution of an organized convective system, perhaps
preceded by discrete supercell development. Some of this activity
may pose a risk for large hail in excess of 2 inches in diameter,
along with strong, damaging wind gusts.
..Kerr/Thompson.. 05/11/2021
ATTN...WFO...CRP...EWX...SJT...MAF...
LAT...LON 29500229 30240282 30520198 30100107 29550044 29059980
28469944 27889936 27569977 26830047 27320138 27530166
27790172 28740195 29500229
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Tue May 11 15:38:00 2021
ACUS11 KWNS 111847
SWOMCD
SPC MCD 111846
GAZ000-FLZ000-ALZ000-112045-
Mesoscale Discussion 0593
NWS Storm Prediction Center Norman OK
0146 PM CDT Tue May 11 2021
Areas affected...Southern Alabama...southwest Georgia...and the
western Florida Panhandle
Concerning...Severe potential...Watch unlikely
Valid 111846Z - 112045Z
Probability of Watch Issuance...20 percent
SUMMARY...A loosely-organized squall line may be capable of damaging
winds as it continues east along the Gulf Coast. However, confidence
in this threat is low, and a watch is not expected.
DISCUSSION...Recent velocity data from KMOB shows outflow associated
with a weak and loosely organized squall line becoming slightly more
organized as it propagates to the east across southwestern AL and
into the FL Panhandle. VWP observations from KMOB show 20-30 knots
winds in the lowest 2-3 km associated with this line, which is
supported by recent observed wind gusts up to 25 knots at the
surface. While severe winds do not appear likely in the near term,
the potential for damaging winds may increase over the next 1-3
hours as the line moves into southeast AL, southwest GA, and the FL
Panhandle where low-level lapse rates are steepening to 7-8 C/km
amid modest daytime heating. The environment ahead of this line
remains supportive for storm maintenance, but it is not immediately
clear if the damaging wind potential will be realized along the
entire line - mainly due to weak low-level shear in the lowest 4 km.
Pockets of intensification are noted in GOES IR imagery over the
past 30 minutes, which suggests that at least localized strong winds
are possible. Due to the low confidence in a more widespread/robust
severe threat, a watch is not expected.
..Moore/Thompson.. 05/11/2021
ATTN...WFO...FFC...TAE...BMX...MOB...
LAT...LON 31398810 31858797 32168747 32368612 32418533 32298476
31718439 31008445 30178501 30048536 30298602 30378661
30328707 30278761 30288793 30928802 31398810
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Tue May 11 15:39:00 2021
ACUS11 KWNS 111900
SWOMCD
SPC MCD 111859
TXZ000-112100-
Mesoscale Discussion 0594
NWS Storm Prediction Center Norman OK
0159 PM CDT Tue May 11 2021
Areas affected...Parts of central into eastern Texas
Concerning...Severe potential...Watch possible
Valid 111859Z - 112100Z
Probability of Watch Issuance...40 percent
SUMMARY...There appears potential for an evolving cluster of
thunderstorms to become better organized and posing increasing risk
for damaging wind gusts by 4-5 PM CDT, if not before.
DISCUSSION...The bulk of increasingly widespread convection
approaching the Interstate 35 into Interstates 20/30 corridors of
central into northeast Texas remains rooted above a cool/stable
surface-based layer. However, across and north of the upper Texas
coastal plain, daytime heating is contributing to erosion of the
shallow leading edge of this air mass, with isolated storms now
initiating along the front, north of College Station and Huntsville.
Beneath steep mid-level lapse rates, boundary-layer moisture,
characterized by lower 70s F surface dewpoints, advecting northward
across and above the cool surface-based air is contributing to
sizable CAPE on the order of 2000-3000 J/kg. As inflow of this air
continues, further intensification of storms along the front is
possible. Eventually this activity may merge into the approaching
upstream convection, which may also begin to intensify as it
encounters increasing inflow of this unstable air.
Although flow in the lower through mid-levels is rather modest in
strength, deep-layer shear, beneath 50-70 kt westerly flow around
300 mb, could eventually contribute to organizing convection which
might pose increasing risk for potentially damaging wind gusts by
21-22Z, if not earlier.
..Kerr/Thompson.. 05/11/2021
ATTN...WFO...SHV...HGX...FWD...EWX...
LAT...LON 31889726 32249610 32509453 31419434 30839572 30699634
30079712 30239797 30749832 31399781 31889726
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Thu May 13 16:39:00 2021
ACUS11 KWNS 131938
SWOMCD
SPC MCD 131938
NEZ000-SDZ000-WYZ000-132215-
Mesoscale Discussion 0605
NWS Storm Prediction Center Norman OK
0238 PM CDT Thu May 13 2021
Areas affected...Parts of northern/western Nebraska and adjacent
portions of southeastern Wyoming and southwestern South Dakota
Concerning...Severe potential...Watch unlikely
Valid 131938Z - 132215Z
Probability of Watch Issuance...20 percent
SUMMARY...Strong thunderstorm development, possibly including an
evolving cluster of storms, appears underway. This may pose a risk
for hail and strong surface gusts which could occasionally approach
or exceed severe limits into early evening. Due to the marginal
anticipated risk, it is not clear that a severe weather watch is
needed, but trends will be monitored.
DISCUSSION...Boundary-layer destabilization is underway across
central portions of the high plains, modest due to low moisture
levels, but becoming maximized as far north as the Nebraska
Panhandle vicinity. This is generally north and east of a
developing weak surface low, and along a strengthening zone of
differential surface heating, which is becoming a focus for
deepening convective development. This is probably being supported
by increasing large-scale ascent, largely due to low/mid-level warm
advection, downstream of a low-amplitude mid-level perturbation
digging within northwesterly flow across the northern Rockies.
Deep-layer ambient mean flow only appears to be strengthening from
20-30 kt, but associated vertical shear, aided by veering profiles
in low to mid-levels, is probably becoming conditionally supportive
of organized convection. With mixed-layer CAPE, particularly around
the Alliance, NE vicinity, as high as 500 J/kg, but up to around
1000 J/kg for surface-based parcels, there appears potential for at
least a few stronger storms capable of producing small to marginally
severe hail.
Given the steep low-level lapse rates associated with the modestly
deep, well mixed boundary-layer, locally strong surface gusts might
be the more prominent convective hazard, aided by sub-cloud cooling
associated with melting and evaporating precipitation. It is
possible that forcing associated with consolidating surface cold
pools, coupled with the larger-scale ascent, could support an
upscale growing, southeastward propagating cluster of storms by
early evening.
..Kerr/Thompson.. 05/13/2021
ATTN...WFO...LBF...UNR...CYS...
LAT...LON 43560347 42309958 41460155 41340384 42450404 42920451
43560347
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Mon May 17 14:14:00 2021
ACUS11 KWNS 171748
SWOMCD
SPC MCD 171747
TXZ000-171915-
Mesoscale Discussion 0649
NWS Storm Prediction Center Norman OK
1247 PM CDT Mon May 17 2021
Areas affected...southeast Texas
Concerning...Severe potential...Watch unlikely
Valid 171747Z - 171915Z
Probability of Watch Issuance...20 percent
SUMMARY...A localized hail and wind threat will persist in the
near-term associated with a southeast moving cluster of
thunderstorms. Elsewhere, a localized severe hail or wind threat
will be possible as additional thunderstorms develop through the
afternoon.
DISCUSSION...A long-lived cluster of thunderstorms, currently
approaching Round Rock, continues to move southeast across central
Texas this afternoon. The most intense portion of this elongated
cluster is occurring along and north of a residual southward moving
outflow boundary from overnight convection. The airmass ahead of
this thunderstorm complex remains extremely moist (precipitable
water values approaching 2") and is increasingly unstable
(mixed-layer CAPE between 2000-3000 J/kg) and uncapped (mixed-layer
CINH less than 25 J/kg).
Despite an increasingly favorable thermodynamic environment ahead of
the complex, kinematically the environment is less favorable for
severe potential as effective-layer shear and low-level shear weaken
with eastward extent. Given the existing thunderstorm cluster
organization, a continued threat for hail and wind will persist in
the near-term. Additionally, given the extremely moist environment
and the presence of an outflow boundary, a brief tornado or two
cannot be ruled out. However, longer-term prospects for severe
potential remain relatively low.
Elsewhere, as mentioned, an increasingly unstable and uncapped
environment across southeast Texas will allow for thunderstorm
development through the afternoon. Localized potential for severe
hail or a wet-microburst will exist, but coverage should remain too
isolated to warrant a watch.
..Marsh/Guyer.. 05/17/2021
ATTN...WFO...LCH...HGX...FWD...EWX...
LAT...LON 30499879 31249812 31309756 31089605 31109514 30819459
30189437 29479446 29069502 29049588 29389705 29629828
30189876 30499879
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Tue May 18 15:51:00 2021
ACUS11 KWNS 181857
SWOMCD
SPC MCD 181857
TXZ000-NMZ000-182130-
Mesoscale Discussion 0672
NWS Storm Prediction Center Norman OK
0157 PM CDT Tue May 18 2021
Areas affected...Parts of east central New Mexico into the Texas
Panhandle
Concerning...Severe potential...Watch unlikely
Valid 181857Z - 182130Z
Probability of Watch Issuance...20 percent
SUMMARY...Slowly intensifying storms are possible near and southwest
through south of the Amarillo, TX vicinity through 3-5 PM CDT. Some
of these may be accompanied by severe hail, and perhaps potential
for a relatively short-lived and weak tornado or two.
DISCUSSION...Thunderstorms have initiated along a low-level
confluence zone, south-southwest through northwest of Clovis, NM.
This appears where mixed-layer CAPE has become maximized (1000+
J/kg) in response to daytime heating, beneath the leading edge of an
elongated cold core (500 mb temps -16 to -18C) associated with the
remnants of a mid-level low emerging from the Southwest. This also
appears south-southwest of a convective outflow boundary associated
with a small cluster of thunderstorms now spreading across and north
of the Interstate 40 corridor of the western Texas Panhandle
vicinity.
With continuing insolation, and strengthening differential surface
heating across it, the outflow boundary may become a focus for
enhanced low-level shear and forcing for ascent, providing a
possible focus for stronger thunderstorm development by late
afternoon. Lower/mid tropospheric wind fields and shear are
otherwise generally modest to weak, but it is possible that
southwesterly flow up to 30 kt, near/above the 500 mb level, could
contribute to sufficient vertical shear for supercell structures
along the boundary.
As a zone of enhanced mid-level forcing for ascent continues
gradually pivoting around the eastern periphery of the mid-level low
through 20-22Z, storms over eastern New Mexico may continue to
increase and intensify while spreading into the Texas Panhandle,
with additional storms also initiating along the outflow boundary.
A few of these storms may eventually pose a risk for severe hail,
with perhaps some developing potential for generally
weak/short-lived tornadoes.
..Kerr/Guyer.. 05/18/2021
ATTN...WFO...LUB...AMA...MAF...ABQ...
LAT...LON 33950270 33460314 33730353 34560328 35100292 35130253
35320191 34420172 33950270
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Tue May 18 15:51:00 2021
ACUS11 KWNS 181930
SWOMCD
SPC MCD 181930
ARZ000-LAZ000-TXZ000-OKZ000-182130-
Mesoscale Discussion 0673
NWS Storm Prediction Center Norman OK
0230 PM CDT Tue May 18 2021
Areas affected...Portions of northeast TX into southeastern
OK...southwestern AR...and northwestern LA
Concerning...Severe potential...Watch possible
Valid 181930Z - 182130Z
Probability of Watch Issuance...40 percent
SUMMARY...A strong to damaging wind threat may gradually increase
this afternoon. Isolated severe hail could also occur. Watch
issuance is possible.
DISCUSSION...A band of convection has persisted early this afternoon
from north-central into northeast TX and far southeastern OK. Ascent
associated with a subtle mid-level vorticity maximum and modest
low-level warm advection are probably aiding these storms. Gradual destabilization of the boundary layer should continue downstream of
this activity across the ArkLaTex region through the remainder of
the afternoon, with the development of MLCAPE around 1000-1500 J/kg
probable. Mid-level flow is expected to fairly modest across this
region through the rest of the day (generally 20-30 kt), and the
lack of stronger effective bulk shear may limit overall storm
organization and intensity to some extent. Still, the ongoing
activity should eventually encounter a more unstable airmass with
eastward extent as convective inhibition continues to weaken this
afternoon. A small cluster similar to the current radar depiction
would pose mainly a strong to damaging wind threat, although
isolated, marginally severe hail may also occur with stronger
embedded updrafts. Other storms may form along an outflow boundary
farther south based on recent visible satellite and radar imagery.
It remains unclear whether any of these storms will strengthen
enough to justify watch issuance, but observational trends will be
closely monitored.
..Gleason/Guyer.. 05/18/2021
ATTN...WFO...LZK...SHV...TSA...FWD...
LAT...LON 33479568 34109572 34659499 34669419 34519346 34209303
33559304 33009323 32489365 31919447 31839484 31859536
32339532 32609543 33079555 33479568
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Thu May 20 16:09:00 2021
ACUS11 KWNS 201859
SWOMCD
SPC MCD 201858
SDZ000-NEZ000-COZ000-MTZ000-WYZ000-202130-
Mesoscale Discussion 0692
NWS Storm Prediction Center Norman OK
0158 PM CDT Thu May 20 2021
Areas affected...Portions of eastern WY...southeastern MT...the
western NE Panhandle...and western SD
Concerning...Severe potential...Watch possible
Valid 201858Z - 202130Z
Probability of Watch Issuance...40 percent
SUMMARY...An isolated threat for marginally severe hail and
strong/gusty winds should gradually increase this afternoon. Watch
issuance is possible.
DISCUSSION...Visible satellite imagery shows convection is deepening
over and just downstream of the higher terrain in north-central CO
and central/eastern WY, with a couple of lightning flashes recently
noted. Stronger mid-level winds associated with a large, closed
upper low centered over the Pacific Northwest are expected to
generally remain displaced to the west of the northern/central High
Plains. But, around 20-30 kt of south-southwesterly flow at 500 mb
should be present by late afternoon. Weak low-level
south-southeasterly winds have transported modest boundary-layer
moisture to the lee of the CO Front Range and Laramie/Bighorn
Mountains in WY, with surface dewpoints generally ranging from the
mid 40s to low 50s. Steep low and mid-level lapse rates are present
across this region, which combined with the limited low-level
moisture and strong diurnal heating should support MLCAPE generally
in the 500-1500 J/kg range by late afternoon.
Current expectations are for storms to gradually move off the higher
terrain and into parts of the High Plains through the remainder of
the afternoon and continuing into the early evening. Both the
limited low-level moisture and rather weak mid-level flow are
concerns for overall storm intensity and organization. Still, about
25-30 kt of effective bulk shear is forecast across the warm sector
by most short-term guidance, which will probably be enough for some
convective organization. Storms may have a tendency to cluster as
they move northeastward with time, especially in eastern WY and
southeastern MT. Isolated strong to severe wind gusts will be a
possibility if this occurs, as the very well mixed boundary layer
will promote efficient downdraft accelerations. Marginally severe
hail may also occur with any initially discrete storms. At this
point, the need for a Severe Thunderstorm Watch this afternoon
remains unclear, but observational trends will be monitored for
potential storm clustering which may locally increase the severe
wind threat.
..Gleason/Kerr.. 05/20/2021
ATTN...WFO...UNR...BOU...CYS...BYZ...RIW...
LAT...LON 45120677 45870625 46350519 46240463 45910404 45420334
43810303 41380274 41160294 41020337 40960398 41000462
41100501 42550534 43810610 44410673 45120677
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Wed Jun 9 14:39:00 2021
ACUS11 KWNS 091809
SWOMCD
SPC MCD 091808
MNZ000-NDZ000-092015-
Mesoscale Discussion 0897
NWS Storm Prediction Center Norman OK
0108 PM CDT Wed Jun 09 2021
Areas affected...Portions of northern Minnesota
Concerning...Severe potential...Watch unlikely
Valid 091808Z - 092015Z
Probability of Watch Issuance...5 percent
SUMMARY...Damaging winds and isolated large hail will be possible
this afternoon before storms move north of the international border
in northern Minnesota. Storms may develop into central Minnesota,
but uncertainty in coverage and intensity are greater. A WW is not
expected this afternoon.
DISCUSSION...Isolated storms have developed near the international
border and in northwest Minnesota in association with a weak frontal
wave cyclone/MCV. Effective shear magnitudes may approach 50 kts in
close proximity to the MCV with a decrease with southward extent.
The strongest storms are expected to occur in northern Minnesota
where the most favorable overlap of buoyancy and shear will exist.
The 12Z INL sounding sampled 7.5 C/km mid-level lapse rate which
will promote a threat for large hail. Damaging wind gusts will also
be possible given strong surface heating. A few storms may also
develop farther south along a weak convergence zone into parts of
central Minnesota. There is uncertainty here as the better mid-level
ascent and shear will remain north and continue to lift away from
the region this afternoon. Damaging winds would be the more likely
threat with southward extent, with any large hail being much more
isolated. A WW is not expected as the strongest storms are expected
to move into Manitoba/Ontario relatively quickly.
..Wendt/Guyer.. 06/09/2021
ATTN...WFO...DLH...MPX...FGF...
LAT...LON 46399606 48409740 49099749 49249443 48639345 47069379
46219428 45959524 45939570 46399606
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Weather Alert@21:1/175 to
All on Sat Jun 19 18:07:00 2021
ACUS11 KWNS 192158
SWOMCD
SPC MCD 192158
SDZ000-NEZ000-NDZ000-MTZ000-WYZ000-192330-
Mesoscale Discussion 1017
NWS Storm Prediction Center Norman OK
0458 PM CDT Sat Jun 19 2021
Areas affected...Southeastern Montana...northeast Wyoming...and
portions of the Dakotas.
Concerning...Severe potential...Watch unlikely
Valid 192158Z - 192330Z
Probability of Watch Issuance...20 percent
SUMMARY...Storm initiation appears possible in the next 1 to 2 hours
across the central and northern High Plains. A narrow corridor of
buoyancy will support a few hours of isolated severe potential with
high-based storms. Uncertainty on storm coverage and severity
remains high.
DISCUSSION...Ahead of a deepening mid-level trough observed on
afternoon water vapor imagery, towering cumulus has become
progressively more agitated from far southeastern Montana into
northeastern Wyoming. Incipient updrafts along the crest of the Big
Horns and higher terrain in southeast Montana suggests the airmass
across the High Plains is likely nearing minimal convective
inhibition. SPC mesoanalysis indicates between 500-1500 J/kg of
MLCAPE have developed in a narrow corridor from the Nebraska
Panhandle northward, owing to steep mid-level lapse rates and
surface mixing ratios between 8 and 10 g/kg. Weak upslope flow,
diurnal heating, and background ascent from the approaching
mid-level wave should further diminish remaining inhibition, and may
allow for convective development in the next couple of hours. CAM
guidance remains unreliable in the weak ascent regime, but does hint
at one or more clusters of storms evolving off the higher terrain
this evening. The primary severe threats will be damaging outflow
winds and hail, given moderate buoyancy and steep low/mid-level
lapse rates.
Across the Black Hills of western South Dakota, cloud debris from
earlier convection is inhibiting strong surface heating casting
doubt on storm initiation in this region. Here, deeper surface
moisture and higher buoyancy may support a locally greater, but more conditional severe threat for wind and hail into this evening. Given
the narrow corridor of destabilization and the uncertainty on storm coverage/intensity, a weather watch is unlikely, though trends will
be monitored.
..Lyons/Guyer.. 06/19/2021
ATTN...WFO...BIS...LBF...UNR...CYS...BYZ...GGW...
LAT...LON 42540325 42570417 43430464 44650494 45680493 46490480
46640474 46820434 46590388 45590312 44680263 43960228
43370213 42610256 42540325
$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)