SPC Mesoscale Discussion

SPC MD 385

MD 0385 CONCERNING SEVERE THUNDERSTORM WATCH 95... FOR PORTIONS OF THE LOUISIANA AND TEXAS COASTLINE
MD 0385 Image


Mesoscale Discussion 0385
NWS Storm Prediction Center Norman OK
0527 PM CDT Wed Apr 14 2021

Areas affected...Portions of the Louisiana and Texas Coastline

Concerning...Severe Thunderstorm Watch 95...

Valid 142227Z - 150030Z

The severe weather threat for Severe Thunderstorm Watch 95
continues.

SUMMARY...A limited threat for severe storms will remain in place
for a couple more hours. Large hail would be the primary threat for
any storms that manage to develop.

DISCUSSION...A surface cold front is currently meandering along the
east-TX coastline, with temperatures in the 80s F and dewpoints
exceeding 70 F ahead of the front. Steep (8+ C/km) mid-level lapse
rates overspreading the warm, moist low-level airmass have promoted
3000-4000 J/kg MLCAPE (per latest Mesoanalysis and RAP forecast
soundings). Despite the favorable thermodynamic environment in
place, along with 35+ kts of effective bulk shear, very limited
deep-layer ascent has precluded a more robust severe threat thus
far. Given that afternoon peak heating is underway, it appears that
low-level lift due to diurnal mixing is insufficient for promoting
organized storms/a severe threat. Some upper support is evident via
the eastward propagation of a small mid-level impulse across
northwest TX, however, it is unclear if the upper support will
influence an uptick in convective development across southeast
Texas.

Should storms manage to develop and mature in close proximity to the
front, especially towards the BEA/VCT vicinity, large hail would
become a concern given the steep lapse rates in place. Conditions
will continue to be monitored for more rigorous convective
development.

..Squitieri.. 04/14/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...LCH...HGX...CRP...EWX...

LAT...LON   27839716 28249789 28669810 29029778 29489684 30029529
            30209403 30029377 29579389 28989501 28549588 27839716 

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SPC MD 384

MD 0384 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR NORTHWEST TEXAS
        
MD 0384 Image

Mesoscale Discussion 0384
NWS Storm Prediction Center Norman OK
0449 PM CDT Wed Apr 14 2021

Areas affected...northwest Texas

Concerning...Severe potential...Watch unlikely 

Valid 142149Z - 142345Z

Probability of Watch Issuance...5 percent

SUMMARY...A set of splitting cells may continue to pose a damaging
hail risk over the next 1-2 hours, with a general weakening trend
expected as they move northeastward this evening. A watch is not
expected due to limited coverage.

DISCUSSION...Splitting cells exist over Taylor and Jones counties as
of 21:45Z, with a very large hail core noted earlier on the
southern/right-moving cell. These cells are located within the
elevated MUCAPE plume, with weak warm advection occurring around 850
mb aiding lift.

The theta-e gradient at 850 mb is forecast to remain
quasistationary, with little increase in advection through evening.
The strong deep-layer effective shear may allow these cells to
persist in severe fashion for a row or two of counties east of their
current location. However, a weakening trend is anticipated after
00Z as they move farther away from the instability axis.

..Jewell/Hart.. 04/14/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...FWD...OUN...SJT...

LAT...LON   32299848 32139938 32249979 32539994 32869996 33639924
            33899823 33669774 33249755 32929758 32559766 32299848 

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