Area Forecast Discussion
Issued by NWS San Angelo, TX

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FXUS64 KSJT 282129
AFDSJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
329 PM CST WED JAN 28 2015

.SHORT TERM...
(Tonight and Thursday)

Very warm afternoon across West Central Texas with temperatures
climbing into the upper 70s and lower 80s across the area as of
3 PM. This will be the warmest day of the week, with a cold front
arriving tomorrow. This front is across the Panhandle this
afternoon, having reached Amarillo around noon. Models are pretty
consistent, dropping the front to near the I-20 corridor from
Sweetwater to Abilene by sunrise Thursday morning and quickly
across the rest of the area by midday. Cooler readings behind the
front, with afternoon highs on Thursday ranging from near 60 along
I-20 to near 70 along I-10. A little milder tonight as well, with
just enough wind to keep temperatures from bottoming out. The cold
spots tonight will be the usual cold air drainage locations, the
Llano River Basin near Junction and the valleys around Sonora and
Ozona.

07

.LONG TERM...
(Thursday night through Wednesday)

Shortwave ridging over the region Thursday night will keep the
forecast dry, but the ridge axis slides east of the area on Friday
with southwesterly flow aloft developing across West TX. This
southwesterly flow will persist through Saturday, downstream of a
broad, cut-off cyclone over northern Mexico. Several shortwave
troughs will move across the region, providing increasing rain
chances on Friday, with PoP really ramping up Friday night and
Saturday.

Precipitable water values are progged to increase to near/just
over 1 inch by Saturday morning, which look to be 2 standard
deviations (or more) above climo for late January. The NAEFS
standardized anomalies for 850 mb meridional wind component is
also more than 1 standard deviation above climatology, suggesting
that unseasonably high rainfall amounts are possible across the
region. Forecast rainfall totals for Friday through Sunday are
near 1 inch areawide, with localized higher amounts possible.
Normal rainfall for the month of January is around 1 inch on
average, and we`ve already seen one event with comparable numbers
this month.

A northern stream trough will dive southeast across the central
Plains on Sunday, with the primary cut-off low remaining to our
west. This will drive a mid-level trough axis across the area,
shunting precipitation chances south of the CWA by late afternoon.
This will push a weak cold front into the area, bringing drier air
into the region for Sunday night and Monday. Post-frontal
temperatures look to be in the lower 50s (comparable to Sunday),
owing largely to the increase in insolation and lack of
precipitation.

Temperatures will warm a bit on Tuesday but are forecast to take a
slight step back by midweek as the aforementioned cut-off low
finally catches a ride in the westerlies and moves east of the
area. The GFS does develop QPF across the Hill Country by Tuesday
as this system traverses the area, but the GEM and ECMWF maintain
a more southerly track, keeping it dry across our neck of the
woods. Given the lack of consistency between these models, no PoPs
were added at this time, with dry weather anticipated Sunday night
and beyond. We`ll continue to watch how the models handle this
ejecting upper low, with the possibility of adding rain chances at
a later time.

Johnson

&&

.PRELIMINARY POINT TEMPS/POPS...
Abilene  45  61  36  49  40 /   0   0   5  20  60
San Angelo  44  69  38  52  41 /   0   0   5  20  60
Junction  44  70  42  55  42 /   0   0   5  10  60

&&

.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

07/25



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