Area Forecast Discussion
Issued by NWS San Angelo, TX

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747
FXUS64 KSJT 141700
AFDSJT

Area Forecast Discussion
National Weather Service SAN ANGELO TX
1100 AM CST SUN FEB 14 2016

.AVIATION...
/18Z TAFS/

VFR ceilings have returned to all sites late this morning and are
expected to continue through the next 24 hours. Patchy stratus
will be possible after midnight Monday, but confidence remains low
that it will affect any of the TAF sites. A weak cold front will
move through West Central Texas this afternoon/early evening.
Ahead of the front expect southwest winds of 6 to 12 knots, with
north winds of 5 to 10 knots behind the front.

&&

.PREV DISCUSSION... /issued 511 AM CST SUN FEB 14 2016/

AVIATION...
/12Z TAFS/

Low cloud development will continue early this morning across
some of our southern and southeastern counties, affecting KJCT
and KSOA with MVFR ceilings. Low clouds may develop as far
northwest as San Angelo. A breakup of low clouds is expected
between 15Z and 17Z, with VFR conditions expected for the rest of
the TAF period. Low-level wind shear is possible early this
morning at our southern terminals, due to a south-southwesterly
45-55 KT low- level jet. Gusty south winds early this morning will
decrease and veer to the southwest by early this afternoon. A weak
cold front will move south into the Big Country late this morning,
reaching KABI by 20Z. The front will make slower progress this
afternoon but should reach a Brownwood to Ozona line by 23Z. North
or north-northeast 8-11 knots winds will follow passage of this
weak front. Mainly light north winds expected tonight across most
of our area.

PREV DISCUSSION... /issued 340 AM CST SUN FEB 14 2016/

SHORT TERM...
(Today and tonight)

A weak cold front will move southeast into the northern and
western Big Country late this morning, and is expected to be just
south of a Brownwood-San Angelo-Ozona line by 6 PM. Temperatures
will be several degrees cooler than yesterday across the Big
Country, where highs will be in the upper 60s to near 70. Farther
south across our central and southern counties, with arrival of
the front just after peak heating and low-level thermal ridging
pattern just ahead of the front, highs are expected to be in the
mid to upper 70s. Low cloud development will continue early this
morning across some of our southern and southeastern counties, and
possibly as far northwest as San Angelo. Gusty south winds early
this morning will decrease and veer to the southwest by early this
afternoon. North-northeast winds will follow the the frontal
passage.

The weak front will sag into our southeastern counties early
tonight before washing out. With light winds, mostly clear skies
and good radiational cooling, overnight lows are expected to be
mostly in the upper 30s to lower 40s. These lows may need to be
tweaked down a few degrees, especially if the post-frontal airmass
is a little drier than currently anticipated.

19

LONG TERM...
(Monday through Saturday)

The progressive synoptic pattern we`ve seen much of the past month
will continue through the next 7 days. Dry, northwesterly flow
aloft will continue through Wednesday, providing mostly sunny
skies and mild temperatures. Temperatures are forecast to remain
above normal each day this week, with rain chances remaining low
through Saturday.

The aforementioned cold front for tonight will result in
northerly winds across the CWA on Monday. The surface pressure
gradient looks relatively weak, but 850mb winds are progged to
increase to near 20 kts around midday. With sufficient vertical
mixing, surface winds are expected to be slightly higher than
suggested by MOS, generally in the 10-15 mph range. However, cold
advection will be minimal. Thus, forecast highs range from the
upper 60s across the Big Country to the low/mid 70s throughout the
Concho Valley and I-10 corridor. Winds will become light after
sunset, with southerly flow resuming after midnight. Increasing
southerly winds late in the overnight period will help maintain
low temperatures in the lower 40s across much of the area, but
sheltered, low-lying areas, especially over the northwest Hill
Country, are likely to drop into mid 30s.

Another shortwave trough will dive southeast across the central
Plains on Tuesday. The attendant surface trough is progged to move
south into West Central TX on Tuesday, but is not expected to
affect temperatures. In fact, afternoon highs on Tuesday are
forecast to be in the mid 70s to near 80 degrees. Again, southerly
flow will quickly resume Tuesday night, keeping minimum
temperatures above normal across the CWA.

The ridge axis will approach from the west on Wednesday,
continuing mostly sunny skies and warm temperatures. Southerly
winds will increase to 10-15 mph on Wednesday and shortwave with
850 mb temperatures progged to warm to near 15C. This should
support max temps near 80F across much of the forecast area. As
the low-level jet intensifies Wednesday night, we should see
stratus return to the Hill Country. The GFS is developing light
QPF, but this looks rather optimistic as the models are usually a
bit too fast with the moisture return. Nonetheless, overnight low
temperatures are forecast to be mainly in the lower 50s with
southerly winds of 10-20 mph.

The flow aloft becomes southwesterly on Thursday, with a fast-
moving shortwave trough zipping east across the Plains late in
the day. Gusty south winds are anticipated across the Lone Star
State Thursday afternoon, with gusts to 30 mph possible across
much of West TX. Temperatures at 850mb are progged to warm
further, suggesting max temperatures once again in the 80s.
Fortunately, low-level moisture return should keep relative
humidities above 30%, limiting the fire weather concerns.

The next front (rather surface trough) is forecast to move into
West Central TX on Friday. Once again, we don`t expect much of a
temperature change behind the wind shift, with afternoon highs in
the vicinity of 80 degrees. Strong quasi-zonal flow aloft is
anticipated as we head into the weekend, with the next trough
taking shape over the western CONUS. There remain some differences
between the GFS and ECMWF, with the former suggesting increasing
rain chances as we move into Sunday. However, the 00z ECMWF is
much drier for our neck of the woods, depicting a much weaker
upper-level trough. We`ll continue to watch this system, as it
looks to be the only legitimate opportunity for precipitation in
the next 7-10 days.

Johnson

&&

.PRELIMINARY POINT TEMPS/POPS...
Abilene  70  39  68  43 /   5   5   0   0
San Angelo  78  39  73  39 /   5   0   0   0
Junction  76  39  75  35 /   5   0   0   0

&&

.SJT Watches/Warnings/Advisories...
None.
&&

$$

Daniels



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