RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Sat Apr 18 06:03:02 UTC 2026.
MD 0489 CONCERNING SEVERE THUNDERSTORM WATCH 132... FOR SOUTHWESTERN THROUGH NORTHEASTERN OKLAHOMA...SOUTHWESTERN INTO SOUTH CENTRAL MISSOURI...ADJACENT PORTIONS OF TEXAS AND ARKANSAS
Mesoscale Discussion 0489
NWS Storm Prediction Center Norman OK
1109 PM CDT Fri Apr 17 2026
Areas affected...southwestern through northeastern
Oklahoma...southwestern into south central Missouri...adjacent
portions of Texas and Arkansas
Concerning...Severe Thunderstorm Watch 132...
Valid 180409Z - 180615Z
The severe weather threat for Severe Thunderstorm Watch 132
continues.
SUMMARY...Thunderstorm intensities are waning with diminishing risk
for severe weather. A new severe weather watch is not anticipated.
DISCUSSION...The southward cold frontal surge continues,
particularly across and south of the Interstate 44 corridor of
Oklahoma, accompanied by 3-5+ mb 2-hourly surface pressure rises and
gusty northwesterly winds. Lift of moist, potentially unstable air
above the leading edge of this air mass is maintaining fairly
vigorous thunderstorm development, which may be locally augmenting
these gusts.
Most unstable inflow near the cold front/dryline intersection
southwest of Altus OK might still be sufficient to support at least
some continuing risk for severe hail across the nearby Red River
vicinity another couple of hours. Otherwise, peak convective
intensities have been gradually waning over the past few hours with
diminishing severe weather potential.
..Kerr.. 04/18/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LZK...SGF...TSA...FWD...OUN...SJT...
LAT...LON 34709987 35499856 36369681 37079437 37749295 36839265
34719498 33599729 32759933 34709987
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN
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SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1153 PM CDT Fri Apr 17 2026
Valid 181200Z - 191200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
UPPER OHIO VALLEY TO THE APPALACHIANS...
...SUMMARY...
Scattered strong to severe thunderstorms capable of damaging winds
and hail will be possible on Saturday across the upper Ohio Valley
and central Appalachians. Isolated severe hail is also possible
across parts of central Texas.
...Synopsis...
A large upper trough with elongated leading speed max will sweep
across the Great Lakes and OH Valley during the day and into the
Appalachians by Sunday morning. Meanwhile, moderate westerlies aloft
will persist across TX with the aid of a subtropical jet.
At the surface, a cold front will move across OH and KY through
early afternoon, and into western NY, PA, and WV late in the day.
This front will also extend far southwestward toward the
northwestern Gulf Coast and into far southern TX. Ahead of the
front, a narrow plume of 50s to lower 60s F dewpoints will exist as
far north as OH and PA, with more robust moisture into TX with upper
60s F dewpoints.
...Upper Ohio Valley/Appalachians...
A remnant line of showers and thunderstorms is expected to persist
near the cold front this morning as it moves across the OH Valley
and toward the lower Great Lakes. Daytime heating will help
destabilize the air mass ahead of this activity, and storm
rejuvenation is expected after 18Z from near Lake Erie into eastern
KY. These storms will mature in the 21-00Z timeframe, affecting
eastern OH, WV, and into PA and possibly southwest NY.
Substantial southwest flow aloft will help to push these storms
quickly east/northeast across the region, and deep-layer shear may
favor scattered cells initially. Marginal hail will be possible,
along with locally strong gusts, especially as storm mode becomes
linear and peak heating has been achieved. Given the narrow
instability axis, storms should wane after sunset.
...South-Central Texas...
Scattered showers and elevated thunderstorms are expected throughout
much of the day as the cold front rapidly undercuts a moist and
unstable air mass. Forecast soundings show MUCAPE parcels rooted in
the 850-700 mb layer, with effective deep-layer shear of 50-60 kt.
Initial activity may develop over central TX during the morning and
through midday, with additional new elevated development translating
southward as the front continually lifts the moist air mass. A few
hail reports at or above 1.00" will be possible.
..Jewell/Moore.. 04/18/2026
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SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1239 AM CDT Sat Apr 18 2026
Valid 191200Z - 201200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not expected on Sunday.
...Synopsis...
A strong mid-level trough will move slowly east from the Great Lakes
to the Northeast on Sunday. At the surface, a large area of high
pressure will extend from the Plains to the Midwest and Southeast.
This will help advance the cold front (and richer moisture) into the
Atlantic and the Gulf.
The prevalence of high pressure and a continental, dry airmass
across most of the country will lead to minimal thunderstorm chances
on Sunday. A few isolated thunderstorms could develop along the
front from eastern Georgia to eastern North Carolina before the
front moves offshore. Scattered thunderstorms are possible along the
eastern shore of the Florida Peninsula, but given the weak
instability, strong to severe concern remains minimal.
Finally, thunderstorms that form over the higher terrain in northern
Mexico on Sunday may move into parts of South Texas and the Edwards
Plateau before weakening in the increasingly hostile post-frontal
environment.
..Bentley.. 04/18/2026
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