Mesoscale Discussion 0177
NWS Storm Prediction Center Norman OK
0149 PM CDT Fri Mar 13 2020
Areas affected...Portions of southwest Texas and southeast New
Mexico
Concerning...Severe potential...Tornado Watch likely
Valid 131849Z - 132045Z
Probability of Watch Issuance...80 percent
SUMMARY...Thunderstorms will increase in coverage and intensity in
the next 1-2 hours and will pose a threat for severe hail, damaging
winds, and a few tornadoes. A Tornado Watch is likely.
DISCUSSION...Low-level upslope flow and heating over much of the
high terrain of northern Mexico, far west Texas, and southern New
Mexico is contributing to widely-scattered thunderstorm development
over the western portion of the MCD area. The coverage and intensity
of these thunderstorms is expected to gradually increase over the
next 1-2 hours. Maintenance of these storms will be supported by an
area of upper 50s surface dewpoints along/southwest of a
quasi-stationary/warm front that is draped from near San Angelo, TX,
west then northwestward to near Fort Sumner, NM. The front is not
expected to move northward much throughout the afternoon.
Although mid-level lapse rates will remain modest, heating of the
relatively moist boundary layer is expected to continue throughout
the afternoon and will result in large enough low-level lapse rates
to support MLCAPE of 750-1500 J/kg along and south/southwest of the
front. MLCIN will range from near zero over the western portion of
the MCD area to -150 J/kg initially over the eastern portion of the
MCD area, but most of the MLCIN south/southwest of the front is
expected to erode by mid afternoon. Furthermore, sufficient MUCAPE
will be present north of the front to maintain storms that develop
along (or cross over) the front throughout the afternoon. Very long,
nearly-straight-line hodographs will support splitting supercells
with a severe hail threat on both sides of the front. Given the
expected maintenance of the stable layer north of the front, the
severe wind threat should be limited to areas of steep low-level
lapse rates along and south/southwest of the front, with the tornado
threat initially limited to storms that can tap the higher SRH
within easterly surface winds along/south of the front.
Given the expected evolution of severe thunderstorms this afternoon,
a Tornado Watch is likely in the next 1-2 hours.
..Coniglio/Grams.. 03/13/2020
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...SJT...LUB...MAF...ABQ...EPZ...
LAT...LON 31560527 32110562 32850567 33410557 33750525 34120475
34080418 33910379 33440323 32640263 32110210 31930202
31570178 31080172 30580178 30370196 29980261 29920343
30360441 30890487 31240508 31560527
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