095
FXUS64 KMAF 281140
AFDMAF

Area Forecast Discussion
National Weather Service Midland/Odessa TX
640 AM CDT Tue May 28 2024

...New AVIATION...

.SHORT TERM...
(Today through Wednesday afternoon)
Issued at 340 AM CDT Tue May 28 2024

For those that have been keeping an eye on the thunderstorm
potential this afternoon, to summarize the thinking here is that it
is surely going to be conditional at best. There`s a lot of moving
parts going into this forecast, so we`re going to break it down by
ingredient: low-level moisture (and thus instability), storm
forcing, and shear.

1) Moisture/instability: Current surface observations show that the
dryline has retreated back into New Mexico and up against our
western high terrain. Dewpoints for those now east of the dryline
are largely in the upper 50s/low 60s. While still worth-while, this
isn`t as high it otherwise could be, due in part to convection
across south-central Texas last evening that has prevented truly
rich Gulf moisture to advect into the area with 65-70+ dewpoints
still hung up east of our area. This issue is exaggerated by the
modest westerlies aloft that will likely mix the dryline to the
central Permian Basin by the early afternoon. All of this to say
that the picture we`re looking at now is quite different than it did
24 or even 12 hours ago and storms appear to be focused further east
than previously thought. Still, steep mid-level lapse rates make up
for the somewhat less rich low level moisture and around 3000 J/kg
is still anticipated along/east of the dryline. This is still plenty
to get intense storms should they form...

2) Forcing: We already talked about the positioning of the dryline
and how storm activity will be largely nudged eastward than previous
thinking. Another potential factor at play will be morning
convection in the vicinity of the Red River/north Texas which is
primed to shoot outflow across Texas. The impact of this boundary
varies greatly from CAM to CAM with the NAM nest being most
aggressive, bringing the outflow through a bulk of the Permian Basin
during the early afternoon. While this outflow will largely serve to
temporarily serve to wash out instability as it moves through, it
could also serve as a forcing mechanism to get storms going in the
CAPE-rich environment south of it, especially if/when it interacts
with the dryline. The most interesting scenario here is from the NAM
nest which brings such a strong outflow in early enough that enough
destabilization occurs behind it though some capping is introduced.
While this is a more extreme scenario, there is still consensus
across the HREF that some outflow could nose into our northeastern
counties in the mid-late afternoon. The dryline itself could also be
a focal point for storms, primarily where local convergence is
highest. Storm forcing and achieving convective initiation remains
the greatest point of uncertainty for this forecast.

3) Wind shear (and ultimately storm-mode): With south-southeasterly
flow ahead of the dryline beneath modest westerlies aloft, bulk
environmental shear is generally 30-40kts, enough to get a splitting
supercell or two (especially across the classic region of Pecos
County where a local maxima in low-level shear is present). The
previously discussed outflow set to move into the Basin at some
point this afternoon will also enhance low level directional shear
with easterly surface winds and with an early outflow arrival
depicted by the NAM and enough destabilization occurs to break the
cap behind this boundary, things could get interesting. Still, the
general idea will be perhaps a few discrete storms to fire off the
boundary (especially across Pecos County or the southeastern Permian
Basin), likely growing upscale and departing east of our area by 03z
this evening.

Needles to say, the forecast remains quite volatile and somewhat
uncertain but it is best to be prepared for storms should they
occur. Generally large hail and damaging winds are the main threats
but an isolated tornado cannot be ruled out. Another sneaky hazard
today will be the heat, especially for the Davis Mountains into the
Big Bend where it`ll be quite hot with Heat Advisories in effect for
this afternoon.

If you have made it this far, congratulations...now we can talk a
little bit about Wednesday. The large outflow boundary serving to
stifle much confidence in this afternoon`s setup (plus the outflow
from any storms that form in our area today) will likely pull good
moisture well into our western zones by Wednesday morning. Between
stratus fills in and likely sticking around for the Permian Basin
and some subsidence from a weak ridge moving overhead should create
stable enough conditions to limit a bulk of the shower/storm
activity. A few storms off the elevated heat sources in the Davis
Mountains and Pecos County are still quite possible. Overall, NBM
seems way too overzealous with PoPs for this period, so have
undercut them by blending in the HREF. Temperatures on Wednesday
will be appreciably cooler in the Permian Basin due to the cloud
cover (with highs only in 80s!) while it remains hot along/south of
the Pecos, especially south of Hwy 90.

-Munyan

&&

.LONG TERM...
(Wednesday night through Monday)
Issued at 340 AM CDT Tue May 28 2024

Wednesday night, convection will be tapering off to the east under
messy zonal flow aloft.  A 35+kt LLJ will provide 35-45kts of deep
layer shear to keep convection ongoing for a few hours during the
evening before things stabilize w/loss of daytime heating.  The
dryline will bank up against the higher terrain, and rich Gulf
moisture will keep overnight minimums well above normal.

Thursday, temperatures rebound to 6-8F above normal, with a slight
chance of convection along/east of the dryline as it mixes east
during the afternoon, and into the evening hours.  Forecast
soundings depict dry subcloud layers and mid-level laps rates 7-8
C/km or better, all w/30-40 kts of deep-layer shear, so the severe
threat continues.  Friday, models bring a boundary in from the
northeast, backing surface flow to the east Friday and Saturday.
This will yield the coolest couple of days in the extended, w/highs
only 3-5F above normal.  Upslope flow will aid in afternoon/evening
convection along/east of the dryline, especially Saturday as long-
range models bring a modest shortwave through the region.

Sunday and Monday, models begin developing an upper ridge south of
the border, resulting in drier conditions and the return of
widespread triple digits to West Texas and Southeast New Mexico.
This looks suspiciously like the summertime ridge, and given that
it`ll be the beginning of June, the timing is about right. Latest
cluster analysis points in the same direction.  Unfortunately, this
will bring an end to any appreciable chances of rain outside
orographic diurnal development in the Davis Mountains each day, and
the long hot summer begins. Stay tuned...

&&

.AVIATION...
(12Z TAFS)
Issued at 634 AM CDT Tue May 28 2024

Relatively light winds out of the south this morning veer to the
southwest at most sites except MAF and FST who stay south-
southeasterly through the mid afternoon. Showers and thunderstorms
will likely fire off the dryline at some point this afternoon and
may impact MAF/FST but too much lingering uncertainty in timing
and location precludes mention in the TAF but will amend as
necessary. Large scale outflow will likely overtake MAF and
possibly other terminals with easterly winds late this afternoon
but gusty/erratic winds from storms may complicate the afternoon
wind field. VFR conditions prevail most of the day until MVFR
CIGs may move in late in the period for MAF/HOB/CNM and possibly
INK.

&&

.FIRE WEATHER...
Issued at 340 AM CDT Tue May 28 2024

Elevated fire weather conditions are expected through next week,
mainly over the higher terrain west of the Pecos on the west side of
a developing dryline each day.  Critical minimum relative humidities
will coincide with increased 20-ft winds each afternoon.  ERCs
remain above the 95th percentile in these areas.  However, fuel
density and limited opportunities for fire starts remain low.  The
one exception will be Saturday afternoon, when the dryline will be
far enough west that lightning starts will be possible in the
Sacramento Foothills, Guadalupes, and areas directly south to the
Presidio Valley.

&&

.PRELIMINARY POINT TEMPS/POPS...
Big Spring               97  65  84  68 /  40  30  20  20
Carlsbad                102  65  93  65 /   0  10  10  10
Dryden                   99  71  94  72 /  50  30  20  10
Fort Stockton           103  69  96  70 /  40  20  20  10
Guadalupe Pass           92  63  88  64 /   0   0  10   0
Hobbs                    99  62  86  65 /  10  20  10  10
Marfa                    97  57  94  56 /  30  20  10  10
Midland Intl Airport     99  65  87  68 /  30  30  20  10
Odessa                   99  67  88  70 /  30  20  20  10
Wink                    104  68  94  70 /  20  20  10  10

&&

.MAF WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory from 1 PM this afternoon to 8 PM CDT this evening
     for Central Brewster County-Chisos Basin-Davis Mountains-
     Davis Mountains Foothills-Lower Brewster County.

NM...None.
&&

$$

SHORT TERM...16
LONG TERM....44
AVIATION...16