Day 4-8 Severe Weather Outlook Issued on Jul 11, 2020
Updated: Sat Jul 11 08:42:02 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
Tue, Jul 14, 2020 - Wed, Jul 15, 2020
D7
Fri, Jul 17, 2020 - Sat, Jul 18, 2020
D5
Wed, Jul 15, 2020 - Thu, Jul 16, 2020
D8
Sat, Jul 18, 2020 - Sun, Jul 19, 2020
D6
Thu, Jul 16, 2020 - Fri, Jul 17, 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 110840
SPC AC 110840
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0340 AM CDT Sat Jul 11 2020
Valid 141200Z - 191200Z
...DISCUSSION...
The intense upper level high over AZ/NM will drift eastward over the
southern Plains during the Day 4-8 period. A more progressive
northern stream is expected during this time, however. Beginning on
Day 4/Tue, an upper trough centered over the northern Plains will
pivot to the Upper Midwest by Day 5/Wed and weaken as it continues
to migrate east across the Great Lakes on Day 6/Thu and eventually
the Northeast late in the period. This will result in a belt of
enhanced west/northwesterly flow shifting eastward from the Dakotas
to the lower Great Lakes atop a seasonally moist and unstable
boundary layer.
A cold front associated with the upper trough and a weak surface low
will shift east/southeast across the Upper Midwest to central KS on
Day 4/Tue. Severe storms appear possible ahead of this boundary
somewhere across the Midwest on Tuesday, but confidence is low
concerning where exactly any greater threat will materialize given
several days of prior convection/possible MCSs and likely some
convection from the Day 3/Mon period continuing into Tuesday
morning.
This uncertainty will persist through much of the period as
mesoscale processes not well resolved at these timescales will
become the major driver of severe storm development. Nevertheless,
the overall pattern appears favorable for several days of severe
storms progressing eastward across the Midwest to the Northeast, and
severe probabilities will likely be needed as mesoscale features
become better resolved with time.
..Leitman.. 07/11/2020
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