Mesoscale Discussion 0696
NWS Storm Prediction Center Norman OK
1156 PM CDT Sun May 19 2019
Areas affected...eastern NM and portions of the OK/TX Panhandles
into western TX
Concerning...Severe potential...Watch likely
Valid 200456Z - 200700Z
Probability of Watch Issuance...80 percent
SUMMARY...Thunderstorms are expected to develop by 1-3 am CDT. Large
hail will be the main concern with activity through early morning. A
watch will likely be needed in the next couple of hours.
DISCUSSION...Strong southeasterly flow through around 1 km continues
to bring rich Gulf moisture northwest across TX into eastern NM late
this evening. Dewpoints have increased 8 to 16 degrees in the last 3
hours from the Davis Mountain region in western TX into southeastern
NM as evidence of this strong moisture surge. Regional 00z RAOBs
from CRP and DRT showed surface dewpoints of 80 and 69 F
respectively. As such, deeper boundary layer moisture is expected to
overspread much of western TX and into far eastern NM overnight. A
resulting surge in instability will accompany the moisture return
and MLCAPE values around 500 J/kg were already shifting northwest
into southeast NM. As this trend continues the next few hours,
modest forcing along a surface dryline and subtle impulses ejecting
from eastward progressing upper trough over the western Great Basin
should trigger convective initiation in the 06-08z time frame. Water
vapor and IR satellite imagery indicate a subtle wave is spreading
northeast across southern AZ and northern Mexico as of 0430z with
increasing cloud cover and cooling cloud temps noted in addition to
more agitated cloud features over southeast NM into far west TX.
This initial activity will likely be elevated given the cool
boundary layer. However, impressive effective shear of 60+ kt with
large, curved hodographs will support rotating/supercell structures.
Hail will be the main concern with this activity overnight, though a
40-50 kt south/southwesterly low level jet could result in upscale
growth into a squall line or bowing segments. Given surface
inhibition, the wind and tornado threat should remain limited until
after sunrise. A watch will likely be needed for portions of the MCD
area by around 06-07z.
..Leitman/Guyer.. 05/20/2019
...Please see
www.spc.noaa.gov for graphic product...
ATTN...WFO...LUB...AMA...MAF...ABQ...
LAT...LON 33080403 34960410 35710420 36220395 36580355 36870265
36880202 36740147 36220095 35420082 34240128 33110180
32310249 32150294 32080338 32480392 33080403