Day 4-8 Severe Weather Outlook Issued on Jul 12, 2020
Updated: Sun Jul 12 08:21:02 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
Wed, Jul 15, 2020 - Thu, Jul 16, 2020
D7
Sat, Jul 18, 2020 - Sun, Jul 19, 2020
D5
Thu, Jul 16, 2020 - Fri, Jul 17, 2020
D8
Sun, Jul 19, 2020 - Mon, Jul 20, 2020
D6
Fri, Jul 17, 2020 - Sat, Jul 18, 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 120819
SPC AC 120819
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0319 AM CDT Sun Jul 12 2020
Valid 151200Z - 201200Z
...DISCUSSION...
...Days 4-6/Wed-Fri -- Upper Midwest to the Northeast...
The upper trough centered over the northern Plains on Day 4/Wed will
slowly migrate eastward across the Upper Midwest/Great Lakes through
Day 5/Thu, and across the Northeast on Day 6/Fri. At the same time,
a strong upper level anticyclone will persist from the southern
Plains into the Southeast. This will keep the zone of enhanced
westerlies associated with the northern upper trough confined to the
Upper MS Valley/Great Lakes and Northeast. Some severe threat could
accompany the eastward progression of the upper trough through the
work week, but confidence is low convection and will largely be
driven by mesoscale processes associated with prior days convection
and where any remnant boundaries and/or MCVs are positioned at the
start of each day. As such, confidence is too low to include 15% or
greater probabilities at this time, but may become necessary in
subsequent outlooks.
...Days 5-8/Thu-Sun -- Northern/Central Plains to the Great Lakes...
Another shortwave upper trough is forecast to develop southeastward
across the Pacific Northwest on Day 5/Thu, and progress eastward
into the northern Plains around Day 7/Sat. As a surface trough
develops across eastern portions of the Dakotas, boundary layer
moisture should increase some on strengthening southerly low level
flow. As stronger southwesterly mid/upper flow overspreads this
seasonally moist/unstable environment, severe storms appear possible
through the weekend from the northern/central Plains into the Upper
Midwest vicinity. Uncertainty over timing and degree of moisture
return preclude introduction of severe probabilities at this time,
though trends will need to be monitored for possible upgrades in the
coming days.
..Leitman.. 07/12/2020
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