SPC AC 211231
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0631 AM CST Fri Feb 21 2025
Valid 211300Z - 221200Z
...NO THUNDERSTORM AREAS FORECAST...
...SUMMARY...
The risk for thunderstorms appears negligible across the U.S. today
through tonight.
...Synopsis...
Early morning surface analysis places the center of an expansive
area of high pressure over MO. This area of high pressure (and its
associated continental arctic airmass) is gradually expected to
shift eastward throughout the day as shortwave trough progresses
across the central Plains and into the Mid MS Valley. This evolution
will maintain low-level offshore trajectories, with the resulting
stable conditions precluding thunderstorm development. The only
exception is just off the South Texas coast, where surface
cyclogenesis is anticipated ahead of a second shortwave trough
forecast to move southward through AZ. Increasing low-level moisture
convergence is anticipated near this low, with warm-air advection
increasing throughout its eastern periphery as well. However, this
low is expected to remain well offshore, keeping any deep convection
over the western Gulf. Warm temperatures aloft will preclude
thunderstorms within any warm-air advection showers that do make it
ashore.
..Mosier/Grams.. 02/21/2025
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
SPC AC 210628
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1228 AM CST Fri Feb 21 2025
Valid 221200Z - 231200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Scattered thunderstorms are possible from the middle and upper Texas
Coast toward the Sabine Valley Saturday evening into early Sunday.
At least some risk of hail may eventually develop.
...Synopsis...
Northwest flow with multiple mid-level shortwave troughs will be
present across the CONUS on Saturday. One of these troughs will
advance from the Southwest into the southern Plains. Low-level flow
will strengthen across the western Gulf with increasing moisture and
strengthening isentropic ascent.
...Southeast Texas and southern Louisiana...
An increase in convection is expected along the Gulf Coast during
the day Saturday and particularly into Saturday night. MUCAPE around
500 J/kg and effective shear around 30-35 knots may result in a few
stronger storms. CAPE heavily concentrated within the hail growth
zone and a cool boundary layer will support the potential for some
hail, but somewhat limited instability may limit the updraft
acceleration needed for larger (1.00") hail. If greater instability
appears more likely, a Marginal Risk may eventually be needed from
southeast Texas and into coastal Louisiana.
..Bentley.. 02/21/2025
WUUS02 PTSDY2
SPC AC 210825
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0225 AM CST Fri Feb 21 2025
Valid 231200Z - 241200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Thunderstorms are forecast across southern Louisiana on Sunday. No
severe weather is expected.
...Discussion...
A mid-level trough will continue to advance southeast into the
northern Gulf on Sunday. Elevated thunderstorms will likely be
ongoing and persist through the morning and early afternoon within a
region of isentropic ascent from south-central Louisiana to
southeast Louisiana. Strong shear will be present as the mid-level
flow strengthens. However, instability will be quite weak.
Therefore, some small hail is possible, but larger hail is not
expected. By late afternoon to evening, expect most of the
thunderstorm activity to move offshore as the surface low develops
and moves into the central Gulf.
..Bentley.. 02/21/2025
WUUS03 PTSDY3
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1930Z
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