Day 4-8 Severe Weather Outlook Issued on Mar 12, 2021
Updated: Fri Mar 12 10:03:04 UTC 2021
Day 4 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Day 5 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Day 6 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Day 7 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Day 8 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
D4
Mon, Mar 15, 2021 - Tue, Mar 16, 2021
D7
Thu, Mar 18, 2021 - Fri, Mar 19, 2021
D5
Tue, Mar 16, 2021 - Wed, Mar 17, 2021
D8
Fri, Mar 19, 2021 - Sat, Mar 20, 2021
D6
Wed, Mar 17, 2021 - Thu, Mar 18, 2021
(All days are valid from 12 UTC - 12 UTC the following day)
Note: A severe weather area depicted in the Day 4-8 period indicates 15%, 30% or higher probability for severe thunderstorms within 25 miles of any point.
PREDICTABILITY TOO LOW is used to indicate severe storms may be possible based on some model scenarios. However, the location or occurrence of severe storms are in doubt due to: 1) large differences in the deterministic model solutions, 2) large spread in the ensemble guidance, and/or 3) minimal run-to-run continuity.
POTENTIAL TOO LOW means the threat for a regional area of organized severe storms appears unlikely (i.e., less than 15%) for the forecast day.
Forecast Discussion
ZCZC SPCSWOD48 ALL
ACUS48 KWNS 121000
SPC AC 121000
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0400 AM CST Fri Mar 12 2021
Valid 151200Z - 201200Z
...DISCUSSION...
Latest runs of the medium-range models exhibit reasonable agreement
through Day 5/Tuesday, as an upper low initially over the central
Plains shifts northeastward across the Missouri Valley and gradually
weakens/dissipates through the Day 4 (Monday) time frame.
Meanwhile, a second low is expected to dig southeastward across
California and the Great Basin Day 4.
Day 5, this low is progged to cross the Four Corners states through
the day, reaching the Texas/Oklahoma Panhandle region overnight. In
advance of this feature, a surface low should develop over the
Panhandle region during the day, with a dryline likely to mix
eastward across West Texas. At this time however, CAPE appears
likely to be quite modest (owing to meager low-level moisture)
during the day into western North Texas and the Panhandles,
suggesting that any severe risk would likely remain
limited/isolated. Overnight, convection may increase farther east
across Oklahoma and into central portions of Texas, but any severe
risk should remain tempered by diurnal cooling/stabilization of the
boundary layer -- and tendency for largely elevated convection.
By Day 6, models begin to diverge more substantially, with respect
to intensity and progression/location of the upper low, and thus
with positioning and strength of associated surface features. While
severe potential may ultimately evolve across the southeastern
quarter of the country Day 6, and continue Day 7 until the
associated surface front move off the East Coast, predictability
concerns preclude any assessment of severe potential through the
latter half of the period.
..Goss.. 03/12/2021
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