665
FXUS64 KMAF 212329
AFDMAF

Area Forecast Discussion
National Weather Service Midland/Odessa TX
629 PM CDT Sat Sep 21 2024

...New AVIATION...

.SHORT TERM...
(This afternoon through Sunday night)
Issued at 143 PM CDT Sat Sep 21 2024

An active afternoon and early evening is ahead for Southeast New
Mexico and West Texas as a potent trough translates eastward from
the Four Corners Region, developing an increasingly positive tilt
through tonight. Ahead of this feature, ascent has started
overspreading western areas, evidenced by scattered showers and
isolated thunderstorms across Southeast New Mexico and the Upper
Trans Pecos, which have been percolating since this morning. This
activity is just a precursor to a round of strong to severe
thunderstorms forecast this afternoon and evening as
destabilization occurs and ascent continues increasing over the
region. CAMs are in good agreement that storms will first initiate
along a corridor from eastern New Mexico southward across Eddy
and Lea Counties to the vicinity of the I-10/I-20 Split. Coverage
will be isolated to scattered, with a 20-50% potential that
locations see storms this afternoon and evening across much of the
area, with the highest potential from Southeast New Mexico and
the western Permian Basin south to the Davis Mountains. While not
every storm will become severe, the most likely area for severe
will be Southeast New Mexico, the northwestern Permian Basin, and
Upper Trans Pecos where midlevel lapse rates of 7-8C/km and MLCAPE
on the order of 1500-2000 g/kg will be realized during peak
heating in an environment characterized by dewpoints in the 60s.
Initiation may be delayed an hour or two given a weak cap over the
area in the wake of the departing ridge, but it will be overcome
by increased ascent and strengthening midlevel flow associated
with the aforementioned trough. Severe hazards include large hail
and damaging winds, though given veering hodographs and ample
shear, a tornado cannot be ruled out. Storms that develop will
move eastward through this evening, though will battle against a
decrease in instability as well as a loss of insolation after
sunset, thus are expected to weaken with a lingering wind threat
possible through the evening.

Storms will largely diminish after midnight, though lingering
showers are possible over the northern Permian Basin ahead of an
approaching cold front that will move into the region late tonight
through Sunday morning. Lows tonight will trend cooler, with 60s
to the west and 70s to the east, with a much cooler day on tap
areawide on Sunday. The timing and location of the front will
dictate temperatures, as well as potential cloud cover and
precipitation, with another round of showers and thunderstorms
expected Sunday associated with the front, mainly across the
Permian Basin, Lower Trans Pecos, Stockton Plateau, and Big Bend.
Have trended temperatures lower than the NBM solution given its
propensity to mishandle fronts, especially as we get into the
transitional fall season, with highs Sunday in the 70s and 80s for
most, with 90s focused along portions of the river valleys, and
upper 60s possible in northern Lea county. While the severe
potential Sunday is substantially lower than today, a few storms
may still become strong in the vicinity of the front, capable of
mainly a damaging wind threat Sunday afternoon. Heading into
Sunday night, rain chances gradually shift southward with the
front, with lows ranging from the upper 40s across northern Lea
county to the upper 60s and lower 70s along the Rio Grande.

JP

&&

.LONG TERM...
(Monday through Friday)
Issued at 143 PM CDT Sat Sep 21 2024

Upper air pattern evolution has come into better agreement with
what the deterministic GFS and ICON models were showing yesterday,
with a short wave trough embedded in larger scale troughing over
the central CONUS, developing down from the Colorado Front Range
into the Southern Great Plains. However, there is uncertainty
regarding how this short wave will develop, with ECMWF, CMC, and
ICON showing the short wave closing off into an upper low east of
the Four Corners and meandering into Thursday and Friday, whereas
the GFS shows the short wave remaining open, with a separate area
of upper level spin over SW TX. LREF TLE-NH ensemble clusters
depict an open short wave similar to the GFS.

If the short wave closes off into an upper low that meanders over
the area, we could see higher rain amounts, but if the short wave
remains open and is east of the area by Wednesday, rain amounts
shown in NBM might be too high. For now, this is looking more like
a high PoP, low rain event, even for this time of year when rain
chances are usually higher. NBM still depicts highest rainfall
amounts by next Saturday near 1 inch over the eastern Permian
Basin, with amounts close to 2 inches over the Western Low Rolling
Plains. Grand Ensemble and ENS, GEFS, and GEPS ensembles are all
in agreement that by next Saturday, highest rain totals will be
farther north of the CWA. We will see whether this changes as this
rainy pattern draws closer.

Widespread severe weather is not anticipated with showers and
storms this week as most instability and shear is forecast to be
north and east of the area. However, proximity of the short wave
and higher speed flow aloft will provide adequate CAPE and shear
for afternoon and evening storms each day, with some of the
stronger storms capable of producing heavy rain, gusty winds, and
some hail.

High temperatures Monday have trended down in the NBM compared to
previous runs, below average with mostly 70s, 60s in higher
elevations, and 80s and 90s limited to the Rio Grande basins. What
the NBM is showing for highs over the Permian Basin may even end
up being on the upper range of what actually occurs if conditions
are mostly overcast and daytime heating is limited, while cold air
advection and high pressure builds in behind Sunday`s cold front.
Another cold front is forecast to drop down into the area Tuesday
into Wednesday. Lift provided by the cold front and mid-level
moisture and instability from the nearby upper disturbance over
the Southern Great Plains again results in a chance of showers and
storms, especially late Tuesday into Wednesday. High temperatures
Tuesday will be warmer than Monday in advance of the next cold
front, but highs will once again decrease Wednesday in cold air
advection behind the second front. After this reinforcing shot of
cooler temperatures, heights and thicknesses increase as ridging
from the western CONUS builds east and allows temperatures to rise
back to near normal by next Saturday and mostly in the 80s, with
associated large scale subsidence reducing rain chances. With
cooler temperatures and absence of 90s and above aside from near
the Rio Grande, and 70s and 80s elsewhere, lows for most of the
area fall into 50s and 60s each night.

&&

.AVIATION...
(00Z TAFS)
Issued at 619 PM CDT Sat Sep 21 2024

Scattered thunderstorms are ongoing at issuance from just west of
HOB south to PEQ, moving northeast. Have included TS mention at
HOB, PEQ, and INK through 02Z, and will continue monitoring and
amend as needed this evening given significant uncertainty in
eastward progression and potential impacts at MAF. Frequent
lightning, erratic gusty winds, and MVFR conditions in heavy rain
and/or blowing dust can be expected in the vicinity of storms.
Winds will be variable and gusty this evening due to convection
and associated outflow boundaries, though away from storms, gusty
southerly to southeasterly winds will continue this evening. A
cold front moving into the area will veer winds to the northwest
and north at all terminals through 16Z Sunday, with increasing
clouds areawide and MVFR ceilings around 1.5kft at HOB and MAF by
daybreak improving slowly toward 18Z. Elsewhere, VFR conditions
will prevail.

&&

.PRELIMINARY POINT TEMPS/POPS...
Big Spring               73  84  58  75 /  10  60  70  20
Carlsbad                 63  79  57  78 /  20   0  20  20
Dryden                   73  91  66  80 /   0  20  70  30
Fort Stockton            71  89  60  75 /  20  30  60  40
Guadalupe Pass           61  77  53  72 /  10   0  10  30
Hobbs                    66  73  52  77 /  40  20  20  20
Marfa                    62  86  54  76 /  20  20  40  50
Midland Intl Airport     72  84  58  74 /  20  40  60  30
Odessa                   72  85  58  75 /  30  40  60  30
Wink                     71  86  60  78 /  30  20  40  40

&&

.MAF WATCHES/WARNINGS/ADVISORIES...
TX...None.
NM...None.
&&

$$

SHORT TERM...84
LONG TERM....94
AVIATION...84