197
FXUS64 KLUB 041111
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
611 AM CDT Fri Apr 4 2025

...New AVIATION...

.KEY MESSAGES...

 - Scattered to numerous showers and isolated thunderstorms are
   expected this evening.

 - Cold, blustery, wet and snowy weather Saturday with some
   accumulating snowfall expected.

 - Quiet weather begins Sunday with a warming trend next week.

&&

.SHORT TERM...
(Today and tonight)
Issued at 305 AM CDT Fri Apr 4 2025

A broad upper trough centered over the Mountain West will drive a
deep swath of Pacific moisture out ahead of it this morning.
Strongest moisture advection will generally be off the Caprock where
rain and thunderstorms are currently observed on radar. Severe
weather is not expected with the strongly sheared environment,
however an isolated severe storm still cannot be completely ruled
out. The convective activity will turn more stratiform around
sunrise, with drizzle and low cloud cover persisting for the
remainder of the morning. Dry air in the low levels will work its
way in during the afternoon, giving areas generally east of I-27 a
brief lull in the precipitation, with higher chances remaining to
the west. As the aforementioned trough shifts eastward this evening,
another influx of moisture advection will overspread the entire
forecast area. While severe weather again is not expected, a few
stronger cells are possible over the southern Rolling Plains,
although CAPE is essentially non-existent and forecast soundings are
quite saturated. Locally heavy downpours will be the main threat
from any storms. Rainfall totals by early Saturday morning should be
on the order of 0.25-0.5" with localized higher amounts possible.
Temperatures will struggle to get out of the mid 50s with the
anticipated cloud cover and will quickly fall through the evening.

&&

.LONG TERM...
(Saturday through Thursday)
Issued at 305 AM CDT Fri Apr 4 2025

Widespread rainfall is expected across the entire CWA Saturday,
including a transition to snow for portions of the Caprock
Escarpment. Heavy snow will be possible in the far southwestern TX
PH. In the mid/upper-levels, a highly amplified, sharply cyclonic,
longwave trough will continue to dig into northern Mexico, with the
primary shortwave trough rounding its base and ejecting into the
southern Great Plains. Moist, isentropic ascent will be particularly
vigorous surface-to-aloft, as the closed low embedded within the
larger-scale waveguide will remain intact throughout the day
Saturday before finally opening up heading into Sunday morning. At
the surface, a strong cold front is expected to surge through the
region Saturday morning, perhaps before sunrise, and pressure
tendencies of 6-8 mb/3 hr will facilitate northerly winds
approaching advisory-level area-wide Saturday. Frontogenetical
forcing beneath the vigorous ascent, in addition to the position of
the closed low as it rotates over the spine of the southern Rocky
Mountains, will augment the development of well-defined deformation
bands by the late morning to early afternoon hours Saturday.

As the closed low rotates over West Texas, a belt of warm, mid-level
theta-e advection atop the post-anafrontal airmass will allow the
columns to cool below freezing across portions of the Caprock
Escarpment, serving as a focus for a transition from rain to snow,
especially across the far southwestern TX PH. The columns will have
already been saturated with respect to water from the widespread
rainfall that will be ongoing, but the combination of the frontal
passage and the presence of the belt of easterly, mid-level flow,
will cause the columns to become supersaturated with respect to ice,
i.e., saturation below the freezing point. Forecast soundings have
consistently exhibited a classic dendritic growth profile across the
northwestern zones, with mean mixing ratios between 3-4 g/kg within
the cold/polar airmass, which is high for a High Plains snow event.
This leads to the possibility for heavy snow, primarily across the
far southwestern TX PH, where snow accumulations of several inches
will be possible. Snow-to-liquid ratios will be low, potentially as
low as 5:1, with the potential for rapid accumulations from large,
aggregated dendrites generated within the deep DGZ, as the columns
should remain saturated through the mid-levels. A Winter Storm Watch
is in effect from 05/06Z-06/06Z (1 AM CDT Saturday through 1 AM CDT
Sunday) for the far southwestern TX PH and northern South Plains.

Elsewhere across the Caprock Escarpment, snow accumulations from a
coating to around an inch will be possible, while a cold rain
remains the dominant precipitation-type for areas south and east of
the far southwestern TX PH. A wide temperature gradient is forecast
Saturday, with highs struggling to climb above freezing across the
far southwestern TX PH while warming into the middle-upper 40s in
the Rolling Plains. The contribution of CAA from the northerly winds
will also result in wind chills falling into the teens to middle 20s
for the entire CWA. Confidence in widespread QPF of near 1.00" or
greater is high, and is reflected in the official forecast. The
potential for thunderstorms is expected to wane entirely Saturday as
the precipitation transitions into a stratiform state beneath the
deformation bands and the more-vigorous, WAA-induced belt of
convection shifts east of the 100th meridian. Black ice will become
problematic for the Caprock and most of the Rolling Plains heading
into Sunday morning, with low temperatures falling into the upper
teens across the far southwestern TX PH and into lower-middle 20s
across the rest of the CWA.

Precipitation is forecast to wane prior to sunrise Sunday as the
closed low transitions into an open wave and finally ejects east-
northeastward into the Osage Plains. Rapid clearing will follow,
with full sunshine set to return Sunday while temperatures warm into
the 50s area-wide. High temperatures may need additional tweaks for
areas that receive several inches of snow; however, the rapidly
increasing SZA (12.5 hours of daylight), in addition to full
insolation, will enhance the rate of melting and sublimation of the
snowpack, especially in areas that received high amounts. Benign,
dry, and warmer weather is forecast heading into next week as a
shortwave ridge amplifies over the Rocky Mountains.

Sincavage

&&

.AVIATION...
(12Z TAFS)
Issued at 603 AM CDT Fri Apr 4 2025

CIGs will fluctuate at all sites this morning, however MVFR should
be the predominant level. Isolated thunderstorms are possible at
KCDS over the next few hours. They also cannot be ruled out at
KLBB or KCDS however confidence was not high enough to include in
the TAF. Drier air will move in by the afternoon. VFR may briefly
return, although MVFR has been prevailed in the TAFs. Light NE
winds will slightly increase this afternoon/evening.

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from late tonight through late Saturday night
for TXZ021>023-027>029.

&&

$$

SHORT TERM...19
LONG TERM....51
AVIATION...19