AWUS01 KWNH 192329
FFGMPD
NMZ000-200515-

Mesoscale Precipitation Discussion 1106
NWS Weather Prediction Center College Park MD
728 PM EDT Sat Oct 19 2024

Areas affected...eastern NM

Concerning...Heavy rainfall...Flash flooding likely

Valid 192327Z - 200515Z

SUMMARY...A south to north axis of heavy rain is likely to
generate widely scattered to scattered flash flooding across
eastern NM into the early overnight hours. Training/repeating
cells are expected to produce 1 to 1.5+ in/hr rainfall rates
leading to additional 2-4 inch totals through 05Z.

DISCUSSION...Regional radar and GOES East visible imagery at 23Z
showed a broken axis of thunderstorms extending from southwestern
Chaves County, north-northeastward into southeastern Colfax
County, containing several areas of overshooting tops. These
storms were located within an instability axis containing 500 to
1500+ J/kg MLCAPE and anomalous precipitable water values of 0.7
to 1.1 inches via 23Z SPC mesoanalysis data. Accounting for
sufficient wind shear aloft, some cells were organized containing
mesocyclones and large hail, with trends in MRMS-derived rainfall
increasing over the past 1-2 hours, currently showing a few areas
with hourly rainfall in excess of 1 inch. Water vapor imagery
showed a potent closed upper level low over AZ which has begun to
slowly fill and was slowly retrograding toward the west, but
individual vorticity maxima have been revolving about the low
center with areas of upper level divergence and diffluence east of
the low center over much of NM. VAD wind data at KFDX and KMAF
showed 850 mb winds have been increasing as well over the past
couple of hours, currently near 30 kt from the southeast.

An axis of low level convergence near a quasi-stationary front
located at the leading edge of an increasing low level jet is
expected to maintain a roughly south to north axis of
thunderstorms across eastern NM through at least 05Z. RAP
forecasts indicate the magnitude of the 850 mb winds increasing
over southeastern NM into the 40-50 kt range, with the leading
edge possibly serving as a focal point for the highest rainfall
rates. While instability is forecast to wane into the overnight
with the loss of surface heating, likely contributing to lowering
rainfall rates later in the night, RAP forecasts indicate at least
500-1000 J/kg MLCAPE will remain over the east-central to
southeastern portion of the state through 06Z. Mean steering flow,
roughly parallel to the axis of low level convergence is expected
to support repeating rounds and short term training of
thunderstorms, allowing for 1 to 1.5+ in/hr rainfall rates in
addition to 2-4 inches of rain along a south to north axis over
eastern NM.

It is thought that the heaviest rain will remain east of the
sensitive burn scars located over the southern Sangre de Cristo
and Sacramento Mountains through 05Z, however, additional, more
isolated cells to the west of the main axis of thunderstorms may
support an isolated flash flood threat within weaker pockets of
instability, forced by strong dynamic lift east of the AZ closed
low.

Areas of flash flooding are considered likely over eastern NM,
though may remain widely scattered in nature. Storms may propagate
more to the east of current HRRR guidance but the flash flood
threat will decrease with eastern extent due to higher FFG values
toward the TX border.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!9qvvrTzyEGHdVp6hoAIxULY2qbMqxx00Djeh1r7RZ3DBWHKMFBy495k6-sQGTkvpkUjc=
56O9wrhA-QGVwRBVO-QlXhI$  for graphic product...

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

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

LAT...LON   36720430 36450338 35750305 33090349 32160431=20
            32120546 32470583 33510612 34530606 35660576=20
            36440507=20

=3D =3D =3D
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