Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 07/30/20

Area Forecast Discussion

National Weather Service Lubbock TX

 620 PM CDT Wed Jul 29 2020

.AVIATION...
TS have moved south of KLBB with redevelopment not expected this
evening. VFR tonight and Thursday. A cold front will move past the
terminals Thursday afternoon. TS may develop along/vicinity of the
front late in the day. Will hold off mention in the TAFs until
better idea of frontal positioning, TS areal extent, and TS
timing.

&&

.PREV DISCUSSION... /issued 230 PM CDT Wed Jul 29 2020/

SHORT TERM...
A surface trough was draped across the CWA this afternoon, with a
weak surface low located in the southern South Plains--likely
spawned from the convection late last night into this morning. An
ACARS sounding from Lubbock at 1524 UTC this morning also observed a
fairly large depth of dry air in the mid-levels, owing to a surge of
low- to mid-level westerly flow infiltrating its way onto the
Caprock. Intense heating is expected by this afternoon, which will
mix out the thermal inversion across the forecast area as
temperatures soar into the upper 90s by mid-afternoon.

Lower 100 mb mean mixing ratios are holding steady at ~13-14 g/kg,
but deep, vertical mixing should cause dew points to fall into the
upper 50s area-wide this afternoon. As the boundary-layer mixes out
entirely, surface temperatures should reach their convective
thresholds and a few isolated, weak multi-cells will be possible
this afternoon across the CWA. The overall coverage of storms will
be limited in both space and time, due to the lack of forcing
mechanism (i.e. no shortwave rotating through the area) and dry air
entraining into what is expected to be narrow updrafts. The best
potential for convective initiation will be in vicinity of the
surface trough where surface convergence is maximized. Convection
that does manage to form should wane quickly after dark.

An upper-level anticyclone located over the Desert Southwest
continues to strengthen, with a subtle mid-level shortwave currently
rotating across the Intermountain West. This shortwave is forecast
to surge southeastward overnight and arrive by the early
afternoon hours on Thursday. Meanwhile, a cold front associated
with a low in the east-central Great Plains will move equatorward
across West Texas during this time. Increasing frontal confluence
and mid-level forcing, in conjunction with strong surface
heating, will enhance the potential for thunderstorm development
along the cold front during the afternoon and early evening hours.
With a linear convective mode expected and deeply mixed sub-cloud
layers, an isolated to potentially scattered damaging wind threat
will be possible in the strongest storms. Timing of convective
initiation is a bit uncertain, and will depend on where the front
is located and the arrival of the associated mid-level shortwave
perturbation.

Sincavage

LONG TERM...
The extended forecast remains somewhat unsettled, at least through
early next week, as West Texas resides on the downstream side of a
western upper trough. This will keep the South Plains region beneath
northerly to northwesterly flow aloft.

Following tomorrow`s round of afternoon/evening convection, some
which could breach severe levels, the stalling cold front will
received a secondary push as a surface ridge sinks southward out of
the Midwest. In addition to renewing the southern push to the front,
and combined with a glancing shot of lift from a shortwave trough
traversing the Great Plains, this will help to renew/maintain rain
chances late Thursday night into Friday morning. We could see low
storm chances linger into the afternoon, though the best focus may
shift south and west of the area, with the frontal zone, by peak
heating. Regardless, convection will develop across the higher
terrain of New Mexico Friday afternoon and there is a good
probability that it will grow upscale into a south-southeastward
propagating MCS through the evening hours. The main question is how
far eastward this MCS can move, which will largely be dictated by
the amount of westerly mid-level flow that will exist. At this point
it looks like locations near the TX/NM line have a decent shot of
getting some rain/wind from this late evening/night activity, though
chances quickly drop off east from there.

Rain chances will be lower, but not zero, for the entire CWA on
Saturday as modest amounts of moisture and instability are present
in the afternoon, though no clear support aside from daytime heating
(and perhaps a lingering boundary somewhere in/near the area?).

This will likely change late Sunday into early Monday as the upper
flow is progged to become more northwesterly (as opposed to
northerly), complete with increased mid-level moisture, a possible
embedded shortwave, and a front backdooring toward or into the
FA. All together, it looks like much of the region will have a
decent shot of convection Sunday night into early Monday, though
the details regarding the forcing features this far out make it
somewhat unclear where the best rain chances will reside. Hence,
we have boosted PoPs over the subdued blended guidance, but have
only ventured into the slight chance to low chance category for
now. We could squeeze out one, or maybe two more days of
northwesterly (to NNW) flow into early next week, which would tend
to favor late evening/night storm chances across our northwestern
zones.

Thereafter, the upper ridge is progged to flatten through the middle
of next week, though shifting more squarely overhead at the same
time. This would tend to heat us up and dry us out. Before then,
temperatures will drop several degrees below average behind the
FROPA late week, with highs on Friday only expected to range from
the middle 80s to lower 90s. After recovering to near average by
Sunday, temperatures will temporarily trend downward thanks to
increased cloud cover, hopefully some rainfall and another FROPA to
kick off the beginning of next week.

&&

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

$$

07