(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 060900
SPC AC 060900
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0400 AM CDT Tue Jun 06 2023
Valid 091200Z - 141200Z
...DISCUSSION...
Upper troughing over the eastern states should move into the western
Atlantic on Day 4/Friday, with upper ridging remaining prominent
from western Canada into the Rockies and much of the Plains. Some
guidance indicates that a low-amplitude shortwave trough embedded
within a southern-stream mid/upper-level jet may advance eastward
from the Southwest and northern Mexico across the southern High
Plains by Friday evening. Isolated thunderstorms will probably
develop along a sharpening dryline across the southern High Plains
in response. Instability and shear appear adequate for some severe
threat with any convection that can form. However, confidence in
thunderstorm coverage is not high enough to include a 15% severe
area at this time. Isolated severe thunderstorms also appear
possible Friday across parts of north FL along/south of a weak
front, and across parts of the northern/central Plains as a separate
cold front advances southward.
An upper trough/low should approach the West Coast on Day
5/Saturday, and move slowly eastward across the western CONUS
through Day 6/Sunday. While upper ridging will likely be maintained
over the Rockies and High Plains, mid-level flow is forecast to
gradually strengthen this upcoming weekend across the southern
Plains. Rich low-level moisture should also return northward over
the southern/central Plains in this time frame. In general, upper
ridging will prevail over the warm sector; but, weaknesses in the
ridging associated with weak mid-level perturbations are evident in
model guidance across the southern Plains through the weekend. Any
thunderstorms that can develop along the length of the dryline, or
perhaps near a front/dryline intersection, should be capable of
producing severe hail/winds. Due to nebulous large-scale forcing,
too much uncertainty currently exists in the placement and coverage
of robust convection to include any severe areas this weekend across
the southern Plains, but model trends will be closely monitored.
Differences in the synoptic-scale pattern across the CONUS become
more substantial in medium-range guidance from Day 7/Monday onward.
Regardless, upper troughing should advance slowly eastward from the
western to central CONUS early next week. As this occurs,
strengthening mid/upper-level flow should overlap the warm sector
and pose a risk for severe thunderstorms. Exactly where the greatest
threat will develop remains highly uncertain given current model
spread. But, an increasing threat for severe thunderstorms is
evident across parts of the southern/central Plains to the MS Valley
early next week.
..Gleason.. 06/06/2023
CLICK TO GET WUUS48 PTSD48 PRODUCT
weather.gov 
@NWSSPC
