RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Thu May 21 04:00:02 UTC 2026.
No Mesoscale Discussions are in effect as of Thu May 21 04:00:02 UTC 2026.
SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0743 PM CDT Wed May 20 2026
Valid 210100Z - 211200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
WEST AND SOUTHWEST TEXAS INTO SOUTH-CENTRAL TEXAS...
...SUMMARY...
Isolated severe storms with hail and strong wind gusts will be
possible across parts of west and southwest Texas this evening.
Isolated severe gusts may also occur in south-central Texas in the
late evening and early overnight period.
...West, Southwest and South-central Texas...
A mid-level shortwave trough is evident over far west Texas.
Large-scale ascent associated with the trough is providing support
for scattered thunderstorm development early this evening. The
storms are located near a quasi-stationary front extending eastward
from near Fort Stockton into the Texas Hill Country. To the south of
the front, surface dewpoints are mostly in the mid to upper 60s F.
The RAP suggests that MLCAPE ranges from around 1000 J/kg near the
front to about 2500 J/kg in the lower Rio Grande Valley southeast of
Del Rio. As the shortwave trough moves into west-central Texas over
the next few hours, new convection is expected to initiate from the
far western Texas Hill Country into southwest Texas. In addition to
moderate instability, the Del Rio 00Z sounding has 0-6 km shear
around 30 knots with 700-500 mb lapse rates approaching 7.5 C/km.
This environment will support isolated severe storm development.
Rotating cells should be capable of isolated large hail. A few
severe wind gusts could also occur. The potential for isolated
severe gusts may continue after midnight across parts of
south-central Texas, as a convective cluster crosses the Rio Grande
River.
..Broyles.. 05/21/2026
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1058 PM CDT Wed May 20 2026
Valid 211200Z - 221200Z
...NO CRITICAL AREAS...
...Synopsis...
With mid-level troughing dominating the western CONUS, a shortwave
trough and associated jet max within the larger-scale pattern will
briefly amplify winds over portions of the central/southern Rocky
Mountains today. However, this feature appears to round the base of
the larger trough tonight into the early morning of Day 2/Friday.
Additionally, a cold front will move through the southern Great
Basin by late in the Day 1 period on early Friday morning.
...Southwest...
Ahead of the cold front, localized terrain-enhanced southwesterly
winds will increase to 10-20 mph as RH falls to 10-20% at peak
heating. A narrow region of stronger west-southwesterly winds (15-25
mph) will develop across eastern UT and western CO prior to the cold
front arrival, though displaced from the lowest RH. As the front
passes in the evening, brief gusty northerly winds and increased
surface moisture will move over the region. The more localized
nature of elevated fire weather conditions and sparsely continuous
fuels precludes the introduction of highlights.
..Stearns.. 05/21/2026
...Please see www.spc.noaa.gov/fire for graphic product...
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SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1058 PM CDT Wed May 20 2026
Valid 221200Z - 231200Z
...NO CRITICAL AREAS...
...Synopsis...
By Day 2/Friday, the shortwave trough within the larger-scale
mid-level trough over the western CONUS will continue eastward,
advancing over the central Plains and Midwest. This leaves light to
moderate northwest flow aloft over the western 1/4 of the CONUS amid
well above normal surface temperatures. Meanwhile, a transitory
ridge over the eastern 1/3 of the CONUS will exist amid post-frontal
below normal temperatures in most locations with chances for wetting
rainfall. Thus, the only area that stands opportunity of concerning
fire weather would be over far western TX and neighboring areas of
NM. However, with only terrain-driven diurnal wind (near 10-15 mph)
combined with RHs of 12-18% during peak heating over that area,
highlights have been ruled out with this forecast issuance.
..Stearns.. 05/21/2026
...Please see www.spc.noaa.gov/fire for graphic product...
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