Day 4-8 Severe Weather Outlook Issued on Jul 24, 2020
Updated: Fri Jul 24 08:57:03 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
Mon, Jul 27, 2020 - Tue, Jul 28, 2020
D7
Thu, Jul 30, 2020 - Fri, Jul 31, 2020
D5
Tue, Jul 28, 2020 - Wed, Jul 29, 2020
D8
Fri, Jul 31, 2020 - Sat, Aug 01, 2020
D6
Wed, Jul 29, 2020 - Thu, Jul 30, 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 240855
SPC AC 240855
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0355 AM CDT Fri Jul 24 2020
Valid 271200Z - 011200Z
...DISCUSSION...
Within the mid-latitude westerlies, models suggest that larger-scale
troughing will gradually dig east/south of the Great Lakes region
during the early to middle portion of next week. As this occurs,
associated forcing for ascent may contribute to considerable
thunderstorm development along and ahead of an associated cold
front, which could impact much of the northern Mid Atlantic Coast
region Tuesday into Wednesday. Although stronger mid-level flow may
continue to tend to lag to the northwest of the surface frontal
zone, at least some model output suggests that moderate to large
CAPE could develop to the east of the Appalachians, and perhaps
support a risk for thunderstorm activity capable of producing
damaging wind gusts. While this potential still appears
low/uncertain enough that severe weather probabilities are
maintained at less than 15 percent, it is possible that this could
change in later outlooks for this period.
In the wake of this troughing, a weaker belt of cyclonic mid-level
flow may gradually develop east of the northern Rockies through the
Southeast states, downstream of increasingly prominent ridging
becoming centered over the Southwest. It appears that one fairly
significant perturbation may round the crest of the ridging, before
digging within the developing northwest flow across the western
Dakotas/Nebraska into the mid/lower Missouri Valley by next
Wednesday. Accompanied by the eastward advection of a plume of
elevated mixed-layer air, associated destabilization may contribute
to an environment conducive to organizing thunderstorm clusters
capable of producing severe wind and hail. However, the
predictability of any such activity at this extended range is also
rather low, maintaining severe probabilities at less than 15 percent
for now.
..Kerr.. 07/24/2020
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