LIVE MAP (ABOVE) ... SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0257 PM CDT Mon Aug 19 2024
Valid 192000Z - 201200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE NORTHERN AND CENTRAL HIGH PLAINS...AND OVER WESTERN MONTANA...
...SUMMARY...
Scattered severe thunderstorms are possible across portions of the
northern and central High Plains, and over western Montana into
tonight. Large hail and severe gusts are the primary hazards.
...20Z Update...
Within the Slight Risk area over the central High Plains, 15-percent
wind probabilities were added over parts of eastern CO. Here, ample
diurnal heating/steepening low-level lapse rates has increased
confidence in a slightly greater concentration of severe wind gusts
-- especially with any clusters that evolve eastward into this
evening. For more details, reference MCD #1956 and Severe
Thunderstorm Watch #639. Farther north, the Slight Risk was expanded
slightly eastward into western ND, where filtered diurnal heating
and an eventual increase in the low-level jet should favor localized
upscale growth and a continued severe-wind risk into tonight. See
MCD #1958 for additional details.
From portions of the Northeast into the Mid-Atlantic, scattered
thunderstorms will continue tracking eastward along/ahead of a cold
front through the afternoon, posing a risk of locally damaging wind
gusts. The Marginal Risk was trimmed slightly behind the front in
the Northeast. For details, see MCDs #1955/1957.
..Weinman.. 08/19/2024
.PREV DISCUSSION... /ISSUED 1117 AM CDT Mon Aug 19 2024/
...High Plains...
Moderately strong westerly mid-level winds are present today from MT
to CO, with several weak perturbations noted on water vapor imagery
within the flow. Steep mid-level lapse rates and dewpoints in the
60s will lead to a narrow corridor of favorable CAPE later today for
strong/severe thunderstorm development. Clusters of convection will
form over the mountains and foothills of CO/WY and spread eastward
into the higher instability axis. Other areas of storms are
expected to develop over the Black Hills, and across parts of
eastern MT. Large hail is the main concern with these storms,
although the risk of isolated damaging wind will also increase
during the late afternoon and evening as outflows congeal.
...Western MT...
12z model guidance continues to agree on the development of
scattered thunderstorms this afternoon over the mountains of western
MT. This region will be on the eastern fringe of stronger flow
aloft, and where full sunshine will aid in destabilization and
steepening of low-level lapse rates. As storms move off the higher
terrain, merging outflows may result in strong/damaging wind gusts
in the more organized storm clusters. One mitigating factor for
severe in this region would be if the persistent cloud cover east of
the mountains limits destabilization.
...Southeast VA/Northeast NC...
Strong daytime heating is occurring today over parts of southeast VA
and northeast NC, where dewpoints in the upper 60s and 70s will
yield MLCAPE values around 2000 J/kg. Scattered afternoon
thunderstorms are expected. Low and mid-level winds are relatively
weak today, suggesting that storms will struggle to organize.
However, given the extent of heating, a few cells may occasionally
pose a risk of gusty winds through the early evening.
...New England...
An upper trough is moving across the Northeast US today, with the
associated surface cold front tracking eastward across much of New
England this afternoon. Scattered thunderstorms are expected along
the front. Visible satellite imagery suggest considerable cloud
cover over this region, limiting daytime heating and suppressing
steeper low-level lapse rates. This should lessen the overall
severe threat today. Nevertheless, a few storms could produce gusty
winds and/or hail.
Read more CHECK UPDATE ZOOM GRAPHIC
http://dlvr.it/TC6y43
Windy.com Temps | Gusts | WU KORD KPWK |
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MOBILE DEVICE? Turn sideways. Weather conditions directly above are near Lakefront. Top tabs refer to O'Hare (official).
Archives for the SPC Convective Outlook are updated daily (approximately) with a live map at the beginning of each article. Follow the link at the end of the article to check for current updates on the NOAA/NWS Storm Prediction Center website. Also, see Archives for Chicago's hourly weather data on CARDINAL NEWS Magazine.
CONVECTIVE | TORNADO | WIND | HAIL
Monday, August 19, 2024
SPC Aug 19, 2024 2000 UTC Day 1 Convective Outlook
SUNRISE AND SUNSET TIMES IN UTC (if you're not logged in to Google)
CHICAGO UTC-6 during CST (Central Standard Time, e.g., winter)
CHICAGO UTC-5 during CDT (Daylight Savings Time, e.g., summer)
CHICAGO UTC-6 during CST (Central Standard Time, e.g., winter)
CHICAGO UTC-5 during CDT (Daylight Savings Time, e.g., summer)