Day 4-8 Severe Weather Outlook Issued on May 4, 2020
Updated: Mon May 4 08:09:03 UTC 2020
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
Thu, May 07, 2020 - Fri, May 08, 2020
D7
Sun, May 10, 2020 - Mon, May 11, 2020
D5
Fri, May 08, 2020 - Sat, May 09, 2020
D8
Mon, May 11, 2020 - Tue, May 12, 2020
D6
Sat, May 09, 2020 - Sun, May 10, 2020
(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 040807
SPC AC 040807
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0307 AM CDT Mon May 04 2020
Valid 071200Z - 121200Z
...DISCUSSION...
An anomalously intense upper trough for this time of year will
persist across the eastern U.S. for much of the Day 4-8 period. This
will largely limit typical early-to-mid May severe chances from the
Plains eastward. That being said, some severe threat could develop
on Day 4/Thursday as a compact upper shortwave trough migrates
through northwesterly flow aloft from MT/WY into the
central/southern Plains, before merging with the larger-scale
eastern trough. At the surface, a cold front will reside deep across
the Gulf of Mexico Thursday morning. As the upper shortwave drops
southeast across the Plains, surface low pressure will develop over
the central/southern High Plains and allow Gulf moisture to return
northward across the southern Plains on increasing southerly
low-level flow. Medium-range guidance differs quite a bit in the
location and track of the low through Day 4/Thu, resulting in quite
a bit of uncertainty in where, if any, severe storms will develop
from western TX across OK and north TX. Additionally, forecast
soundings indicate quite a bit of MLCIN, which may further limit
severe potential. As such, probabilities will not be introduced at
this time, but trends will need to be monitored closely.
By Day 5/Fri, another cold front will drop southward across the
southern Plains and southeastern states. Rich boundary-layer
moisture will be limited to TX and parts of the lower MS Valley, but
confidence is low regarding severe potential given continued
model-to-model inconsistency. The surface cold front should move
offshore into the Gulf of Mexico, once again depleting boundary
layer moisture, while strong surface high pressure builds over much
of the U.S. east of the Rockies through the end of the forecast
period.
..Leitman.. 05/04/2020
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