Day 4-8 Severe Weather Outlook Issued on May 6, 2020
Updated: Wed May 6 08:04:03 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
Sat, May 09, 2020 - Sun, May 10, 2020
D7
Tue, May 12, 2020 - Wed, May 13, 2020
D5
Sun, May 10, 2020 - Mon, May 11, 2020
D8
Wed, May 13, 2020 - Thu, May 14, 2020
D6
Mon, May 11, 2020 - Tue, May 12, 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 060801
SPC AC 060801
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0301 AM CDT Wed May 06 2020
Valid 091200Z - 141200Z
...DISCUSSION...
Severe storms are not expected Day 4/Sat and Day 5/Sun. A deep
trough will persist across the eastern U.S. during this time.
Meanwhile, surface high pressure east of the Rockies will confine
any appreciable boundary-layer moisture to far south TX and the FL
peninsula.
While the eastern trough persists, an amplified upper ridge over the
western states will shift eastward through Day 6/Monday as an upper
low approaches the Pacific Northwest coast. Medium-range guidance
suggests a weak impulse may eject across the central/southern
Rockies on Monday, resulting in lee cyclogenesis and modest moisture
return across parts of the southern Plains. This could result in
some limited severe potential across parts of the central/southern
High Plains on Monday, but concerns over quality of moisture, and
differences in the strength/timing and placement of the shortwave
impulse, preclude severe probabilities at this time.
While differences exist between ECMWF/GFS solutions, there is a
clear shift in the upper-level pattern by the middle of next week.
The Rockies upper-level ridge is forecast to shift eastward over the
Plains on Day 7/Tue while a trough digs across the western states
and ejects eastward to the High Plains by the end of the period.
This will induce lee surface low development, allowing Gulf moisture
to return across the southern and central Plains. Timing differences
among forecast models leads to too much uncertainty to include
severe probabilities at this time, but it appears likely that severe
potential will increase across the southern and central Plains by
the end of the forecast period.
..Leitman.. 05/06/2020
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