Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX

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FXUS64 KEWX 262337
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
637 PM CDT Mon Oct 26 2020

.AVIATION (00Z TAFs)...
The leading edge of the cold front has cleared south of the area. The
cold, dense airmass is shallow and OVC MVFR to IFR ceilings currently
prevail behind it. Lowering of ceilings into IFR to LIFR are forecast
tonight along with areas of -RA/DZ and isolated SHRAs possible. The
ceilings may rise back into the MVFR category for southern areas
Tuesday afternoon. Gusty NW to NE winds will prevail tonight, with
some gusts between 20-30KT.

&&

.PREV DISCUSSION... /ISSUED 308 PM CDT Mon Oct 26 2020/

SHORT TERM (Tonight through Tuesday Night)...
A broad upper level trough is currently draped across the Northern
Plains and extends into the Desert Southwest with a cut off low
setting up over the four corners region. Throughout the short term
period this cut off low will meander southeastward towards Texas,
keeping below normal temperatures in place as well as upper level
support for continuing cloudiness and showers.

There has been some difficulties with forecasting this front, but
the NAM has performed well with the overall timing and cold
temperatures behind the front. Given that this front is shallow but
strong, it is not surprising that the NAM handled it well. Currently,
the front is working it`s way through South-Central Texas and as of
this writing, extends from Carrizo Springs to San Antonio to Luling.
This boundary will continue to work it`s way southward and clear the
region by this evening. Seeing some isolated heavier showers being
forced up along the boundary itself but should see continued
isolated to scattered activity to continue behind the front.

The temperature forecast for the next 24 hours has been tricky with
a large spread of solutions on how the front is handled. Given how
the NAM has performed in the past with shallow cold fronts and how
it has trended so far, went with a temperature forecast that is
heavily influenced by the NAM. This results in much cooler
temperatures than what the NBM is indicating with lows tonight in
the mid 30s in the Hill Country and low 50s in the Coastal Plains
with a gradient in between. Large scale ascent from the upper level
low to our west should lead to decent coverage of showers on Tuesday
with CAMs indicating better coverage for western areas and along the
Rio Grande. Temperature forecast tomorrow has a high bust potential
but going with the colder solution given the expected cloud cover
and rain chances. Forecast highs for Tuesday are in the mid 40s for
interior parts of the Hill Country, mid to upper 50s along the I-35
corridor and climbing into the 60s for parts of the Coastal Plains.

Cooler than normal temperatures and chances for precip continues
into Tuesday night. Accumulations through Tuesday will be nothing to
write home about given the light to drizzly nature, some isolated
locations may pick up 0.50-1.00 inches, especially over the western
Hill Country and along the Edwards Plateau. Areas elsewhere can
expect 0.10-0.25 inches.

LONG TERM (Wednesday through Monday)...
An upper level low initially located over far southern New Mexico
and far west Texas will slowly lift northeast into the Texas
Panhandle and western Oklahoma on Wednesday. Another cold front will
accompany this system and this front will move across south central
Texas on Wednesday. Gusty northwest winds likely accompany this
front, especially across the Rio Grande plains where a tight surface
pressure gradient will reside. Rain chances will continue for a good
portion of the area on Wednesday, with locations along and north of
Highway 71 being favored for the better rain chances during the
morning hours. As the system continues to move away from the region,
we will see a decrease in rain chances from west to east for the
afternoon hours. Temperatures on Wednesday will still remain below
normal, but will warm compared to Tuesday as we expect a gradual
decrease in cloud cover during the afternoon hours.

The weather pattern for the mid to late week period will be fairly
quiet as mid-level ridging builds in behind the departing upper
system. Gusty northwest winds remain in place on Thursday with winds
decreasing and becoming north-northeast on Friday. This pattern will
yield dry weather along with daytime highs in the mid 60s to lower
70s and overnight lows in the lower 40s to lower 50s.

As we head into the upcoming weekend, temperatures will continue to
warm, with highs generally in the 70s along with overnight lows in
the mid 40s to mid 50s. Another cold front is set to move into the
region either late Sunday or early Monday. As of now, it does not
appear this front will have a big impact on our temperatures, but it
should we should see enough cool air to help keep temperatures
slightly below normal as we head into early next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              42  52  50  60  46 /  50  30  60  50  -
Austin Bergstrom Intl Airport  43  53  51  61  44 /  50  30  60  40  -
New Braunfels Muni Airport     44  53  52  65  46 /  40  30  60  30  -
Burnet Muni Airport            39  47  46  57  43 /  60  40  70  50  -
Del Rio Intl Airport           41  49  45  65  44 /  70  60  70  -    0
Georgetown Muni Airport        41  49  49  59  43 /  50  40  60  60  -
Hondo Muni Airport             44  53  49  68  44 /  60  40  60  20   0
San Marcos Muni Airport        44  53  51  62  44 /  40  30  60  40  -
La Grange - Fayette Regional   48  57  56  65  47 /  40  30  50  40  -
San Antonio Intl Airport       44  53  52  66  48 /  50  30  60  30  -
Stinson Muni Airport           46  55  53  67  46 /  40  30  60  30  -

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

Short-Term/Aviation...Runyen
Long-Term...17


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