• Storm Prediction Center 03 08

    From LU9DCE@21:5/101 to ALERT on Sat Aug 3 08:10:02 2019
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    ESTACION DE PACKET RADIO - BUENOS AIRES (GF05OM)
    BOLETINES INFORMATIVOS PROGRAMADOS (BIP)
    SLACKWARE LINUX - HELLOCODELINUX@GMAIL.COM
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    SPC 1200Z Day 1 Outlook
    Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1145
    PM CDT Fri Aug 02 2019
    Valid 031200Z - 041200Z
    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER THE NORTHERN
    HIGH PLAINS...
    ...SUMMARY... Isolated strong to severe thunderstorms are possible
    this afternoon over the northern High Plains. A few storms producing
    strong wind gusts cannot be ruled out from Oklahoma into north Texas. ...Synopsis... A shortwave trough will move east across the Canadian
    Prairies, with a flattening of an upper ridge over MT. Midlevel winds
    of 30-35 kt will progress across MT and into the western Dakotas,
    with 500 mb temperatures cooling to around -10 C. At the surface,
    a weak front/wind shift will approach the MT/ND border during late
    afternoon, providing lift of an unstable air mass with dewpoints
    near 60 F.
    To the south, an upper high will remain centered over the Four
    Corners states, with northerly midlevel winds of 25-30 kt from the
    central Plains into north TX. Here, a plume of upper 60s to low
    70s F dewpoints will remain, providing sufficient instability for
    areas of thunderstorms despite warm temperatures aloft. The primary
    focus for daytime storms will be near an inverted surface trough,
    roughly from north TX into central OK.
    Elsewhere, scattered daytime storms will occur over parts of the
    Southeast and Mid Atlantic, well east of the upper high and where
    temperatures aloft will be relatively cool.
    ...Northern High Plains... Strong heating combined with cooling
    aloft will result in steep lapse rates through a deep layer, with
    an uncapped air mass near a north-south oriented boundary moving
    across eastern MT. A band of 35 kt midlevel westerlies, increasing
    to 50-60 kt near 300 mb, will provide long hodographs favoring
    splitting cells as little if any low-level jet is expected. A few
    storms will be capable of severe hail, likely developing around 21Z,
    from the eastern border of MT toward the Black Hills. Storms are
    not expected to get too far east into the Dakotas due to capping. A
    few strong wind gusts are also possible.
    ...Central OK into north TX... Areas of showers and
    thunderstorms are expected to be ongoing early in the morning over central/east-central OK, and possibly approaching the Red River and
    into northeast TX by late morning. West of this non-severe activity,
    stronger heating will occur. Only weak surface convergence will
    exist over western north TX into southwest OK, but it will likely
    support isolated afternoon redevelopment. Forecast soundings show
    perhaps 1500 J/kg MLCAPE, with weakly veering winds with height and
    little shear. While a few strong storms producing localized wind
    gusts cannot be ruled out, at this time the severe threat appears
    too low for a risk area.
    ..Jewell/Nauslar.. 08/03/2019
    SPC 0600Z Day 2 Outlook
    Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1253
    AM CDT Sat Aug 03 2019
    Valid 041200Z - 051200Z
    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHEAST ND...NORTHEAST SD...AND NORTHWEST MN...
    ...SUMMARY... Severe thunderstorm are possible across portions of
    the northern Plains and Upper Midwest on Sunday.
    ...Synopsis... Upper ridging centered over the southern High Plains
    early Sunday is expected to slowly drift westward/southwestward
    throughout the day. Northeastern portion of this upper ridge is
    expected to dampen in response to a shortwave trough moving through
    the Canadian Prairie Provinces and into northwest Ontario and the
    adjacent Upper Midwest. In contrast, some building of the ridge is
    anticipated across the Pacific Northwest. At same time, broad and
    generally weak cyclonic flow is anticipated across the eastern CONUS.
    Surface pattern will predominantly be characterized by a weak
    gradient and diffuse baroclinicity. The only exception is across the
    northern Plains and Upper Midwest, where a cold front is expected
    to move through Sunday afternoon and evening.
    ...Northern Plains...Upper Midwest... A cold front is expected to
    move through eastern portions of the northern Plains and into the
    Upper Midwest on Sunday afternoon and evening. Ample low-level
    moisture will likely exist ahead of this front, with dewpoints
    likely in the mid to upper 60s. This favorable low-level moisture
    coupled with convergence along the front and steep low-level lapse
    rates is expected to result in thunderstorm development.
    Mid-level lapse rates will be modest but the warm and moist surface
    conditions will help support moderate buoyancy, with MLCAPE likely
    around 2000 J/kg. Additionally, enhanced mid-level flow will be
    spreading into the region, contributing to strengthening vertical
    shear. As a result, the environment will likely support strong to
    severe thunderstorms capable of large hail and strong wind gusts.
    Farther west (across the western Dakotas and adjacent portions
    if southeast MT and northeast WY), early morning showers and
    thunderstorms will likely give way to mostly clear skies and strong
    diurnal heating. Convergence near a triple-point-like feature at
    the intersection of the cold front and lee trough is expected to
    result in convective initiation. Steep mid-level lapse rates and
    moderate vertical shear support a severe thunderstorm threat with
    any storms that do develop. Coverage uncertainty precludes higher probabilities with this forecast, but increased probabilities may
    be needed in future outlooks.
    ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind:
    15% - Slight Hail: 15% - Slight
    ..Mosier.. 08/03/2019
    SPC Day 1 Fire Weather Outlook
    Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK
    1241 AM CDT Sat Aug 03 2019
    Valid 031200Z - 041200Z
    ...NO CRITICAL AREAS...
    ...Synopsis... The Four Corners high remains in place with
    mostly wet thunderstorms developing across the region this
    afternoon/evening. An upper-level shortwave trough will move
    across southwest Canada and likely result in downslope flow across northwest/north-central Montana. Locally elevated conditions will
    likely develop with westerly sustained winds around 15 mph and
    RH values of 20-30%. Elevated conditions may also develop across
    portions of southern California as very dry and breezy conditions
    are expected during the afternoon and evening including possible
    Sundowner winds.
    ..Nauslar.. 08/03/2019
    ...Please see www.spc.noaa.gov/fire for graphic product...
    SPC Day 2 Fire Weather Outlook
    Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK
    1256 AM CDT Sat Aug 03 2019
    Valid 041200Z - 051200Z
    ...NO CRITICAL AREAS...
    ...Synopsis... The Four Corners high will weaken slightly as an
    upper-level shortwave trough tracks southeast across the northern
    Plains on Sunday. However, the upper-level ridge will likely amplify
    into British Columbia in the wake of this trough passage. Weak
    mid-level troughing off the West Coast will help transport moisture
    northward in the Intermountain West, including the inland Pacific
    Northwest.
    While upper-level heights will likely rise over Oregon on Sunday,
    guidance suggests the increase of sub-tropical moisture aided by a
    weak mid-level disturbance could result in isolated dry thunderstorms
    in central/eastern Oregon. However, given the low predictability
    of this forecast, no areas were included. Additionally, elevated
    conditions may develop across inland portions of southern California
    Sunday afternoon/evening.
    ..Nauslar.. 08/03/2019
    ...Please see www.spc.noaa.gov/fire for graphic product...

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