463
FXUS64 KLUB 011115
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
615 AM CDT Wed May 1 2024

...New AVIATION...

.SHORT TERM...
(Today and tonight)
Issued at 311 AM CDT Wed May 1 2024

In classic West Texas fashion, the first day of May should hit the
ground running with dryline storms later today and especially by
this evening. Early morning water vapor imagery showed gravity waves
rolling west over the region courtesy of two MCSs in OK, but
otherwise our W-SW flow aloft was devoid of any meaningful features.
This will change later this morning as SW winds aloft pick up some
steam ahead of an elongated trough overspreading the Intermountain
West. At the surface meanwhile, a dryline roughly from Dora-Dimmitt-
Amarillo at 2 AM is expected to retreat another 60 miles or so ahead
of increasingly moist southerlies and eventually some low clouds by
daybreak. Eastward mixing of the dryline this afternoon doesn`t
appear particularly aggressive thanks to the deepening moisture and
more importantly a diffuse surface low drifting from eastern NM into
southeast CO by this evening. By peak heating, most high res
guidance paints the dryline along a line from Silverton southwest to
Lubbock and Brownfield which seems reasonable.

East of the dryline, MLCAPEs should soar to 2500-3500 J/kg with
modest CIN overall and 30-35 knots of deep layer shear. Marginal CIN
and poor anvil-level SR flow would tend to favor a shorter window
for supercells early on, before ample DCAPE near the dryline raises
the chances of storm modes becoming increasingly messy and linear.
On that note, several models (CAMs and globals) depict a H7 trough
currently along the Sierra Madres that lifts northeast through the
day before triggering dryline storms over the western Permian Basin
around 21Z and growing quickly upscale thereafter. Given large DCAPE
along the dryline and straight hodographs, there is a growing signal
from CAMs that this initially supercellular convection could be
quite efficient with downbursts and more importantly left movers
that race north and into our southern South Plains this evening
complete with damaging winds and blowing dust. Past events such as
this often accelerate the dryline`s evening retreat and expand
chances for additional storms. NBM`s westward extent of PoPs on the
Caprock look good for this setup, but its values were raised
considerably off the Caprock by this evening as a linear MCS is
likely to evolve with wind and heavy rain the greatest threats.

A second and more conditional area for storm initiation later today
could involve an outflow boundary currently loitering over our
northeastern counties from nocturnal storms in southwest OK. This
boundary appears rather diffuse overall and will more than likely
wash out through the day given how much modification will ensue in
the next 12+ hours. Convection should depart our eastern zones
toward midnight all the while the dryline returns to NM and a cold
front works its way south across the western TX Panhandle. NBM temps
today and tonight needed no change.

&&

.LONG TERM...
(Thursday through Tuesday)
Issued at 311 AM CDT Wed May 1 2024

A generally quieter weather day is expected on Thursday as an early-
day cold front passes southward through the region. The front itself
will not be particularly strong or quick-moving as upstream pressure
rises remain modest and deepening surface troughing over eastern NM
and the Permian Basin slow its southward progression. Even behind
the front temperatures will still warm well into the 80s with the
more notable post-frontal change being a reduction in near-surface
moisture and relative lack of cloud cover given the drier upstream
airmass. Some models still depict isolated convection on Thursday in
the vicinity of a remnant dryline, but this should be well to our
east and will therefore carry a dry forecast over the entire
forecast area Thursday through early Friday. Guidance is in good
agreement that low level moisture will increase once again
beginning on Friday as surface flow obtains a stronger easterly
component, which will also result in high temperatures falling
back near seasonal averages. Thunderstorm potential on Friday is a
bit more unclear as some models hint at scattered storms firing
within the moist upslope regime, but large-scale forcing will
still be quite weak with only a very modest midlevel wave progged
to approach the region during the evening with inhibition also
appearing fairly significant due to a strong capping inversion.
Still, the uncertainty and increased moisture does support
maintaining low PoPs off the Caprock Friday afternoon and evening.

An additional cold front will pass through the region on Saturday,
with flow aloft also progged to strengthen through the day as well.
A majority of model guidance still points to the late Saturday
through early Sunday period as most favorable for potential
widespread rainfall as a more significant upper level disturbance
transits overhead within the stronger southwest flow aloft.
Specifics are uncertain at this range, but ensemble consensus
suggests that most of the region has a good chance (50-80%) of
receiving one tenth of an inch of rain or more over the weekend.
Early next week, a much deeper upper trough is progged to develop
over the western CONUS, but at this point its projected evolution
would bring a return of dry and breezy conditions to our area Monday
through Tuesday.

&&

.AVIATION...
(12Z TAFS)
Issued at 615 AM CDT Wed May 1 2024

Beginning to see MVFR visbys and lower CIGs develop from CDS on
north behind an outflow boundary, although it`s unclear if these
conditions will become prevailing or not. Satellite and models
suggest VFR is more likely to win out overall at CDS and also at
LBB where a second layer of stratus could threaten around sunrise.
Toward this evening, ISO TS should develop near LBB and grow in
coverage as they shift E-NE toward CDS. However, this threat is
still 12+ hours out and not worthy of a TS mention at the moment.

&&

.FIRE WEATHER...
Issued at 311 AM CDT Wed May 1 2024

Dry and breezy conditions are likely this afternoon across the far
southwest Texas Panhandle and northwest South Plains behind a
dryline. Fuels in these areas are more receptive to fire spread and
when combined with southwest winds of 15 to 20 mph and RHs falling
to around 10 percent, a Rangeland Fire Danger statement is justified
for Parmer and Bailey Counties from 1 PM until 8 PM. Farther east,
thunderstorms (some severe) will increase in coverage by this
evening with heavy rainfall possible off the Caprock.

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SHORT TERM...93
LONG TERM....30
AVIATION...93