033
AWUS01 KWNH 161553
FFGMPD
TXZ000-NMZ000-162130-

Mesoscale Precipitation Discussion 0274
NWS Weather Prediction Center College Park MD
1152 AM EDT Thu May 16 2024

Areas affected...eastern New Mexico

Concerning...Heavy rainfall...Flash flooding possible

Valid 161551Z - 162130Z

Summary...Showers and thunderstorms will expand in coverage in the
vicinity of an upper low through this afternoon. Rainfall rates at
times will likely exceed 1"/hr, which could result in 1-2" of
rainfall. Isolated flash flooding is possible.

Discussion...The regional radar mosaic this morning indicates
rapid expansion of convecton across New Mexico. This convection is
blossoming in two regimes, one across central NM within steepened
lapse rates beneath the upper low, while a second area is forming
to the east in response to PVA ahead of a vort max and within the
LFQ of a subtropical jet streak. Widespread ascent will continue
to allow this convection to expand, with intensification also
likely within favorable thermodynamics characterized by PWs of 0.5
to 1 inch (west to east) and SBCAPE increasing towards 1000 J/kg.

In the vicinity of the upper low, elevated instability is
maximized which is producing pockets of MUCAPE of 500+ J/kg
according to the SPC RAP. Although PWs are modest around 0.5
inches, this is still around the 75th% for the date, and modest
easterly flow out of Texas should allow PWs to continue to climb.
These increasingly favorable thermodynamics should allow for rain
rates to climb towards 1"/hr as progged by HREF neighborhood
probabilities, although minimal bulk shear will keep convection
generally of the pulse variety. However, storms redeveloping
across the terrain, and within an area of very weak mean flow
(850-300mb winds just 5 kts) could result in brief but efficient
rainfall accumulations of 1-2". Should these slow moving storms
move atop any burn scars or across sensitive terrain, isolated
flash flooding could occur.

Farther east into the Piedmont and Pecos River Valley, impressive
synoptic ascent within the LFQ of a subtropical jet streak will
act in tandem with PVA atop the more robust thermodynamics to
produce heavier rain rates within convection. Here, the HREF
neighborhood probabilities reach 50-60% for 1"/hr and 10-20% for
2"/hr later this aftn, which could be additionally enhanced
through storm organization as bulk shear reaches 30-45 kts. Storms
that develop in this area may be faster moving on 20 kts of mean
wind from the SW, but aligned Corfidi vectors suggest potential
training, which is already evident in radar imagery. Additionally,
across this area storms may move off the terrain and merge into
clusters, causing repeated rounds of heavy rain. Despite soils
being relatively dry here from a lack of recent rainfall, training
or multiple rounds of these intense rain rates could still produce
isolated instances of flash flooding.


Weiss

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...ABQ...EPZ...MAF...

ATTN...RFC...ABRFC...WGRFC...NWC...

LAT...LON   36850508 36630474 36060423 35400405 35010378
            34570311 33680308 32560309 32020339 31950399
            32180484 32370534 32830573 33580597 35090638
            35730650 36430605 36760563