625
FXUS64 KMAF 210532
AFDMAF

Area Forecast Discussion
National Weather Service Midland/Odessa TX
1232 AM CDT Sat Sep 21 2024

...New AVIATION...

.SHORT TERM...
(This afternoon through Saturday night)
Issued at 139 PM CDT Fri Sep 20 2024

WV imagery shows the west coast trough inching down the SoCal
coastline this afternoon, resulting in progressive southwest flow
aloft over West Texas and Southeast New Mexico. The ESE
progression of this feature is whittling down thicknesses, and
highs this afternoon should be 2-3 F cooler than yesterday as a
result. A weak dryline is already shaping up west of the
Guadalupes, and upslope flow will kick off some isolated to
scattered convection over the higher terrain this afternoon.

This activity will diminish somewhat w/loss of daytime heating,
but models develop a 40+kt LLJ overnight, which could keep it
going into the overnight hours. This will also, along w/mid/high
cloud, retard radiational cooling, keeping overnight minimums
~13-15F above normal.

Saturday, the upper trough is forecast to eject to the Four
Corners by 00Z Sunday. This will push a Pac front into the CWA,
but models have been consistent in stalling it over the
northwestern zones. This will serve as a focus for increased
chances of convection, mainly during the afternoon and evening.
CAMs continue to develop 35-45 kts of deep layer shear over the
northwest half of the CWA at the trough approaches. Forecast
soundings depict dcape in excess of 1000 J/kg, and dry subcloud
layers/inverted-V signatures. Mid-level lapse rates continue to be
tepid, and steeper rates favorable to severe hail continue to
remain north and west of the CWA. Thus, damaging winds appear to
be the main threat. If sever hail transpires, northwest Eddy
County looks most favorable. Thicknesses continue to diminish,
especially northwest, highs should drop another 5 F on average.

Saturday night, a cold front approaches from the north,
w/convective chances spreading northeast as the trough ejects
further up into Colorado. The NAM12 still has the front north of
the area at 12Z, but cooler air from the Pac front looks to filter
into Southeast New Mexico, cooler overnight lows there.

&&

.LONG TERM...
(Sunday through Thursday)
Issued at 139 PM CDT Fri Sep 20 2024

Ridging will continue to weaken as troughing develops over the
central CONUS by this weekend and a series of embedded short waves
move near the area. The first short wave is depicted in all
deterministic models to develop from the Four Corners into the
Midwest and Great Plains late Sunday into Monday. A second short
wave is depicted in the GFS and ICON models to develop and amplify
from the Front Range of the Colorado Rockies into the Southern
Great Plains. Afterward, models and forecast grids indicate lower
rain chances as thicknesses and heights rise with ridging building
in again across the southern CONUS. Frequent rain chances late
this weekend into the end of next week are indicated in
deterministic and ensemble models courtesy of this active weather
pattern aloft as well as lift provided by surface cold fronts. The
first cold front/dryline oriented SW to NE associated with the
short wave late Sunday into Monday is expected to bring isolated
to scattered shower and storm chances to the area. The second cold
front oriented more east to west and moving south late Tuesday
into Wednesday is expected to bring widespread shower and storm
chances late Tuesday into Wednesday before rain chances begin to
taper off Thursday into Friday.

By next Saturday, the Grand Ensemble, European ENS ensemble, NCEP
GEFS ensemble, and Canadian GEPS ensemble all depict at least
half an inch of rain north of I-10 by next Saturday. NBM rain
totals for next Saturday depicts an inch or more of rain only over
the northern Permian Basin, particularly the Western Low Rolling
Plains where amounts approach 1.50 inches and expected totals have
increased in most recent runs to near 2 inches in the
northeasternmost parts of the CWA. Higher amounts closer to 1 inch
were over Lea County, but have come down below 0.50 inch in most
recent runs. GEPS is an outlier, showing amounts over 1 inch north
of 1-10 and above half an inch south of I-10 by next Saturday,
whereas ENS shows lowest amounts south of I-10, with Grand
Ensemble and GEFS most similar and in between the higher rain
total forecast in the GEPS and lower rain total forecast in the
ENS. Spread in GEPS shows possibility of at least 1.50 inches for
most of the Permian Basin in the mean and 75th percentiles. We
will continue to monitor the forecast for rain totals for this
week to see how this changes. While the forecast shows wetting
rains expected, this is expected to be in the form of daily shower
and storm chances during the afternoon, and it is possible that
if the upper air pattern features troughs with associated mid-
level moisture and instability located farther north over the
central CONUS, widespread rain will be less likely. Additionally,
there has been a trend for models to overpredict rain totals and
then lower totals as an extended rainier weather pattern draws
near.

Widespread severe weather after this Saturday is not currently
indicated in SPC forecasts, but model soundings depict sufficient
shear and CAPE for the possibility of strong storms. As is common
during active weather, there is uncertainty regarding timing and
placement of forcing mechanisms. We will see how the smaller scale
mesoscale details shape up as next week draws closer.

With increased cloud and rain chances limiting daytime heating,
highs near to below average Sunday in the 80s, 90s Upper Trans
Pecos and near the Rio Grande, triple digit heat along the Rio
Grande, will give way to highs around 5 degrees below average in
the 70s north of the Rio Grande basins and 80s within and south of
the basins Monday, with 90s limited to along the Rio Grande.
Temperatures warm up to near average Tuesday but again cool down
similar to a few degrees below average Wednesday with the second
cold front passage. Highs Monday and Tuesday as well as lows
Monday night and Tuesday night have trended lower in most recent
NBM runs. Highs remain in the 80s, 70s in higher elevations, and
90s limited to near the Rio Grande and along the Pecos River in
the southern Permian Basin Thursday into Friday, as cloud cover
and rain chances decrease. Lows slightly above average in the 50s
and 60s, 70s near the Rio Grande are expected each night Sunday
night through Friday night, with lows below average only expected
for northernmost parts of the CWA Sunday night. Monday is
currently expected to have the lowest high temperatures in the
long term.

&&

.AVIATION...
(06Z TAFS)
Issued at 1217 AM CDT Sat Sep 21 2024

VFR conditions are expected the next 6 hours. MVFR CIGs may arrive
at MAF/HOB for a few hours between 12-18Z before conditions go
back to VFR. TS will develop after 18Z, lasting until almost 06Z
possibly affecting any of the terminals. Have left out of TAFs due
to uncertainty in timing but aircraft ops will be affected to some
extent.

Hennig

&&

.PRELIMINARY POINT TEMPS/POPS...
Big Spring               74  87  58  78 /  10  60  60  30
Carlsbad                 65  86  58  78 /  20  10  20  20
Dryden                   74  92  69  84 /  10  20  40  20
Fort Stockton            71  91  63  79 /  20  40  40  30
Guadalupe Pass           61  81  56  72 /  10   0  10  20
Hobbs                    67  84  55  77 /  40  30  30  20
Marfa                    64  87  59  78 /  20  30  30  50
Midland Intl Airport     73  87  59  75 /  20  40  60  30
Odessa                   73  88  61  75 /  30  40  50  30
Wink                     72  91  63  79 /  30  30  40  30

&&

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

$$

SHORT TERM...44
LONG TERM....94
AVIATION...10