RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Mon Apr 22 09:52:02 UTC 2019.
No Mesoscale Discussions are in effect as of Mon Apr 22 09:52:02 UTC 2019.
SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1240 AM CDT Mon Apr 22 2019
Valid 231200Z - 241200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTHWEST AND CENTRAL TEXAS...
...SUMMARY...
Thunderstorms associated with an isolated large hail and wind damage
threat are expected to develop across parts of Texas on Tuesday
afternoon and evening.
...Southern Plains...
An upper-level low will move slowly southeastward across northern
Mexico on Tuesday as west to southwest mid-level flow remains over
the southern Plains. At the surface, a cold front will move
southeastward across west-central and north-central Texas. The
airmass will moisten south of the front with surface dewpoints
reaching the mid to upper 60s F. In response, a pocket of moderate
instability is forecast to develop along and just south of the front
from Del Rio extending east-northeastward into the Texas Hill
Country. Thunderstorms are forecast to initiate and organize along
the front during the late afternoon where the models are showing
steep low to mid-level lapse rates and moderate deep-layer shear.
For this reason, a severe threat is expected to develop across
southwest and central Texas from the late afternoon into the
evening. Supercells with large hail and wind damage will be
possible. Organized multicells with damaging wind gusts and hail
appear likely in areas where mesoscale conditions become most
favorable.
...MAXIMUM RISK BY HAZARD...
Tornado: 2% - Marginal
Wind: 15% - Slight
Hail: 15% - Slight
..Broyles.. 04/22/2019
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SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0212 AM CDT Mon Apr 22 2019
Valid 241200Z - 251200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTH-CENTRAL AND SOUTHEAST TEXAS...
...SUMMARY...
Thunderstorms associated with a wind damage and large hail threat
are expected to develop across parts of south-central and southeast
Texas on Wednesday.
...Southern Plains...
An upper-level low is forecast to move from northern Mexico into
west Texas on Wednesday. West-southwesterly mid-level flow will
remain across much of the eastern half of Texas. At the surface, a
cold front is forecast to advance southeastward across central and
southwest Texas. Ahead of the front, a moist airmass should be in
place with surface dewpoints in the mid to upper 60s F. In response,
moderate instability appears likely to develop by Wednesday
afternoon from the lower Rio Grande River east-northeastward across
south-central Texas. The NAM and ECMWF are somewhat in agreement,
showing convective potential along this corridor along and just
ahead of the front. In addition to moderate instability, NAM
forecast soundings at 21Z Wednesday for San Antonio show 0-6 km
shear in the 50-60 kt range. This combined with steep low to
mid-level lapse rates will be favorable for large hail and isolated
damaging wind gusts. The severe threat is expected to develop in the
early afternoon and persist into early evening.
..Broyles.. 04/22/2019
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0348 AM CDT Mon Apr 22 2019
Valid 251200Z - 301200Z
...DISCUSSION...
...Thursday/Day 4 to Friday/Day 5...
On Thursday, an upper-level trough is forecast to move from the
southern Plains into the Arklatex with a cold front moving eastward
across the western Gulf Coast States. Thunderstorms are forecast
ahead of the front in the lower Mississippi Valley. Moderate
instability and deep-layer shear should be sufficient for a severe
threat. The timing of the upper-level trough and magnitude of
instability suggest that there is some uncertainty for Thursday.
On Friday, the upper-level trough is forecast to move eastward to
the eastern Seaboard with the cold front advancing to the eastern
Gulf Coast States. Moderate instability and deep-layer shear are
forecast across the southern half of the Florida Peninsula where an
isolated severe threat will be possible. Timing issues with the
upper-level trough make uncertainty too great to add a severe threat
area at this time.
...Saturday/Day 6 to Monday/Day 8...
From Saturday into Sunday, the medium-range models move a shortwave
trough eastward into the Mississippi Valley and develop an
upper-level ridge across the southern and central Plains. Moisture
return is forecast to take place across the Great Plains where
thunderstorm development will be possible each day. The greatest
chance for a severe threat appears to be on Monday across Kansas and
southern Nebraska. Even so, model differences introduce a lot of
uncertainty so will maintain predictability too low.
On Monday, large model spreads suggest that predictability will be
very low late in the day 4 to 8 period.
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1245 AM CDT Mon Apr 22 2019
Valid 221200Z - 231200Z
...Synopsis...
An upper-level low located over the Desert Southwest will shift
southeastward slowly, reaching portions of southern Arizona/northern
Mexico by the end of the forecast period. Consequently, most of the
modestly enhanced flow along the base of the trough/low will reside
outside of the CONUS, except for portions of the southern High
Plains where mid-level flow of 30-35 kt will enter by mid-afternoon.
At the surface, a cold front will sag south through the central High
Plains and stall across portions of the OK/TX Panhandles and
northeastern New Mexico. Meanwhile, a remnant dryline will extend
south into portions of south-central New Mexico.
...Southern New Mexico...
West of the dryline, afternoon temperatures will approach the upper
70s to lower 80s F with resulting RH values falling into the lower
teens. Vertical mixing will allow winds near to the surface to be
sustained near 10-15 mph, gusting to 20 mph, during the afternoon.
Thus, elevated fire-weather conditions are expected where fuels
remain marginally receptive. The previous forecast has been refined
slightly to account for higher RH values that are now forecast into
portions of far southwestern New Mexico, and slight adjustments were
made elsewhere based on the last high-resolution HRRR/RAP model
guidance.
..Karstens.. 04/22/2019
...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
1246 AM CDT Mon Apr 22 2019
Valid 231200Z - 241200Z
...NO CRITICAL AREAS...
...Synopsis...
The upper-level low located over the Desert Southwest/northern
Mexico will shift eastward, entering portions of the Big Bend and
West Texas by the end of the forecast period. Farther north, a
predominantly zonal flow pattern will exist across the northern tier
of the CONUS. At the surface, high pressure will settle into the
Great Basin and much of the central U.S., with a stationary front
lining up from the Southern Plains into the Ohio Valley. Light
offshore flow can be expected Tuesday morning across portions of
southern California. In general though, fire-weather concerns remain
low, precluding the introduction of any highlights at this time.
..Karstens.. 04/22/2019
...Please see www.spc.noaa.gov/fire for graphic product...
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