Silverton, Texas Weather Forecast Discussion

742
FXUS64 KLUB 090532
AFDLUB
Area Forecast Discussion
National Weather Service Lubbock TX
1232 AM CDT Tue Sep 9 2025
...New SHORT TERM, LONG TERM, AVIATION...
.KEY MESSAGES...
Updated at 1223 AM CDT Tue Sep 9 2025
- Isolated thunderstorms, some severe, will be possible across
   portions of the Caprock this afternoon and evening.
- Dry and hot weather is expected Wednesday through Friday.
- Low storm chances remain forecast this weekend.
&&
.SHORT TERM...
(Today and tonight)
Issued at 1223 AM CDT Tue Sep 9 2025
In the mid/upper-levels, a closed low embedded within an amplifying,
neutrally-tilted trough was rotating over Cape Mendocino and into
the Klamath Mountains. Farther east, the subtropical ridge continues
to steadily amplify over the Intermountain West and is beginning to
emerge into the High Plains, with predominately northwest flow
advecting over the CWA. The 09/00Z objectively analyzed UA charts
observed a negligible change to the geopotential heights despite the
deep-layer flow veering northwestward, as the apex of the ridge is
located over the central Rocky Mountains. The subtropical ridge will
continue to shift eastward over the next 24 hours, as the shortwave
troughing to the west begins to pivot into the Great Basin while
becoming more sharply cyclonic. This will maintain the position of
the leading edge of the southern-stream 250 mb jet streak over the
CWA, resulting in a corridor of strong divergence beneath what will
be an uncapped airmass by peak heating Tuesday afternoon.
At the surface, the CWA remains within a broad fetch of moist,
southerly-to-southeasterly flow, with a diffuse trough located along
the edge of the Mescalero Escarpment that connects to a lee cyclone
near TCC. Little change to the state of the airmass is expected
throughout the short-term period, as surface troughing will remain
parked to the west of the NM state line due to the subtropical ridge
shifting over W TX. The combination of increasing geopotential
heights and full insolation will allow temperatures to breach 90
degrees area-wide Tuesday afternoon, with winds remaining backed to
the south-to-south-southeast in response to cyclogenesis near the
Raton Mesa. Deep mixing of the boundary-layer will occur, with
mixing heights soaring into the mid-levels and LCL/LFCs rooted near
700 mb. (An inspection of the 09/00Z RAOB from WFO ABQ sampled the
PBL top near 600 mb amidst west-northwesterly flow.)
Isolated-to-widely-scattered, high-based thunderstorms are forecast
to form along the aforementioned surface trough, with storms
crossing the NM state line after 21Z. The weak steering flow will
govern propagation versus advection, with storms propagating along
outflow(s), which may result in constructive interference during the
late afternoon hours such that a loosely-organized cluster or two
may develop. Inverted-V boundary-layer profiles beneath sufficient
hydrometeor-loading of updrafts will maximize outflow-related theta
deficits beneath cloud base, with the potential for a few storms to
generate severe-caliber wind gusts up to 70 mph. Hail up to the size
of quarters may accompany the best-organized cores, especially if a
cell can develop a mid-level mesocyclone and attain a rightward
propagation component to its movement. Heavy rainfall will remain
localized, with a limited potential for flash flooding.
The orientation of the storm-relative winds at anvil-level will also
cause anvils to advect southeastward in the path that cells will be
propagating, which may result in some pre-stabilization of the
airmass before nocturnal decoupling of the boundary-layer occurs
after dark. This should keep storm chances confined solely to the
Caprock through Tuesday evening, with storms diminishing entirely
after dark due to the effects of diabatic stabilization and the
subsidence aloft. Low PoPs (i.e., 20-percent/slight chance)
introduced by the previous shift have been redrawn across most of
the Caprock between 21Z-10/03Z. Fair weather will follow heading
into Wednesday morning, with mild temperatures and light winds.
Sincavage
&&
.LONG TERM...
(Wednesday through Monday)
Issued at 1223 AM CDT Tue Sep 9 2025
The previous forecast assessments remain on track, with little
change necessitated for this package. At the beginning of the
period, the subtropical ridge will be centered over the Great Plains
ahead of a sharply cyclonic, neutrally-tilted trough wobbling over
the Sierra Nevada Mountains. Large-scale subsidence will preclude
any potential for storms Wednesday through Friday, and a persistence
forecasting technique has once again been applied for each of those
days due to the slow, eastward progression of the subtropical ridge
and near-neutral geopotential height tendencies. Above-normal high
temperatures continue to be forecast Wednesday through Friday, with
highs peaking in the lower-middle 90s area-wide, which is about 5-7
degrees above seasonal norms.
Global NWP guidance continues to converge on the timing of an
anticyclonic wave break over the polar latitudes by the end of the
week and into this weekend, with a well-defined PV anomaly
propagating towards the Pacific coast. The sharply cyclonic trough
previously meandering over the Great Basin should become open by the
weekend and eject into the central Great Plains, and there appears
to be an indication of a gyre-like behavior to the cyclonic flow to
evolve over the Intermountain West as the aforementioned PV anomaly
moves onshore. Ultimately, should a cyclonic gyre attempt to evolve
or become established, its position will dictate PoPs for the
weekend and into early next week. Therefore, low storm chances
continue to be reflected for the tail-end of the forecast period,
but adjustments will be made as the week progresses and global NWP
guidance converges on the state of the upper air pattern.
Sincavage
&&
.AVIATION...
(06Z TAFS)
Issued at 1223 AM CDT Tue Sep 9 2025
In the immediate term, a cluster of decaying TSRA north of CDS
will continue to shift southward with a brief period of thunder
possible at CDS overnight, but convective impacts at CDS (or any
other site) look unlikely through the rest of tonight. Otherwise,
there is a slim chance of a brief period of MVFR CIGs after
sunrise at LBB and PVW, but confidence in this occurring is too
low for TAF mention at this time. Later this afternoon, iso-sct
TSRA are expected to develop to the west of LBB and PVW and may
impact those sites during the 21z-03z timeframe. Strong and
erratic gusts will be possible, but will address convective
potential this afternoon/evening in later issuances once
confidence improves. Expect VFR to prevail area-wide otherwise.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...09
LONG TERM....09
AVIATION...30

NWS LUB Office Area Forecast Discussion