Day 4-8 Severe Weather Outlook Issued on Jul 27, 2020
Updated: Mon Jul 27 08:40:03 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, Jul 30, 2020 - Fri, Jul 31, 2020
D7
Sun, Aug 02, 2020 - Mon, Aug 03, 2020
D5
Fri, Jul 31, 2020 - Sat, Aug 01, 2020
D8
Mon, Aug 03, 2020 - Tue, Aug 04, 2020
D6
Sat, Aug 01, 2020 - Sun, Aug 02, 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 270838
SPC AC 270838
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0338 AM CDT Mon Jul 27 2020
Valid 301200Z - 041200Z
...DISCUSSION...
Medium-range models indicate that a fairly broad and deep mid-level
low, initially over the northeastern Pacific, will undergo
considerable deformation while being forced eastward and
northeastward within the mid-latitude westerlies. There appears
good agreement with the evolution of negatively tilted mid-level
troughing pivoting toward and inland of the British Columbia and
Pacific Northwest late this work week, but subsequent developments
north of the international border are more unclear. It does appear
that there will be substantive initial further building of
downstream mid-level ridging across the northern U.S. Rockies into
the Canadian Prairies. And strong mid-level ridging may be
maintained across the eastern U.S. Great Basin, northern Rockies and
adjacent northern Great Plains, ahead of a trailing short wave
impulse into early next week.
Downstream of this ridging, models suggest that mid-level flow may
remain generally weak to the east of the Rockies. However, a
convectively-enhanced perturbation digging within northwesterly flow
across the central and southern Great Plains may contribute to
amplifying upper troughing centered along the middle/lower
Mississippi Valley. It might not be out of the question that this
could be accompanied by the development of additional clusters of
storms with the potential to produce strong wind gusts, particularly
Friday into Saturday. However, it also appears possible that
initially warm mid-levels and weak lapse rates limit available
instability.
Due to a combination of continuing general low potential for a
regional severe weather event, and the apparent low predictability
of the synoptic and sub-synoptic developments, severe weather
probabilities are being maintained at less than 15 percent.
..Kerr.. 07/27/2020
CLICK TO GET WUUS48 PTSD48 PRODUCT
weather.gov 
@NWSSPC
