Area Forecast Discussion
Issued by NWS San Angelo, TX

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FXUS64 KSJT 161732
AFDSJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
1232 PM CDT WED APR 16 2014

.AVIATION...
/18Z TAFS/
VFR conditions through this evening with MVFR ceilings expected to
move into the area after midnight. Gusty south winds will continue
through the late afternoon. Winds will diminish, and we will lose
our gusts shortly after 00Z/7PM tonight. Between 09Z and 12Z, MVFR
ceilings near 1500 feet will move into our southern areas,
eventually spreading to KSJT and KABI. These low clouds will
linger well into the mid to late morning hours, especially for
eastern sites. 20

&&

.PREV DISCUSSION... /ISSUED 1034 AM CDT WED APR 16 2014/

DISCUSSION...
Updated the forecast to issue a Red Flag Warning for areas
northwest of a Sweetwater to Throckmorton line. Sweetwater AWOS,
and the Haskell mesonet sites were both with a few percentage
points of reach Red Flag conditions already this morning. While,
moisture is expected to increase across the area this morning,
models are often a bit too aggressive with moisture return. And if
that`s the case again today, relative humidity values should fall
below 20 percent in the next 2-3 hours. With winds already greater
than 20 mph, and gusting to around 40 mph, have gone ahead and
issued the Red Flag Warning for northwestern areas of the Big
Country from late this morning through this evening. 20

PREV DISCUSSION... /ISSUED 619 AM CDT WED APR 16 2014/

AVIATION...
/12Z TAFS/

VFR conditions will prevail across West Central Texas terminals
through this evening, although a veil of high clouds will spread
across the area. The main aviation issue for today will be strong
winds, as southerly winds increase and begin into the 25 to 35 kt
range by late morning. We will likely see MVFR cigs begin to
approach the southern terminals around Junction and Brady by right
around sunrise Thursday morning, but given the timing uncertainty
at the end of the forecast period, left them out for now.

PREV DISCUSSION... /ISSUED 347 AM CDT WED APR 16 2014/

SHORT TERM...
(Today and Tonight)

Much warmer early this morning across West Central Texas, with
readings in the 40s and 50s cross the area. South winds have
stayed up all night so far, and with both the KSJT and KDYX wind
profiles showing a 50 to 60 knot low level jet just above the
surface, winds will stay up for the rest of the night as well.

These winds will quickly mix down this morning, creating breezy
conditions across the area today. Otherwise, with temperatures
already off to a warmer start and with strong warm advection,
model guidance numbers well into the 70s look reasonable. Mild
tonight as the low level jet intensifies and keeps temperatures
well into the 50s.

07

LONG TERM...
(Thursday into Tuesday)

There is a slight chance of showers Thursday across the Big
Country as an upper trough moves across the region. Lift with this
system is mainly to the north and there is fairly strong cap in
place. However, a few showers possible in lower levels beneath the
cap.

Another stronger upper trough will move across the region this
weekend. Atmospheric column saturates Saturday morning with fairly
strong lift indicated into early Saturday evening. GFS SB CAPES
are up to 1000 J/KG Saturday afternoon with 0-6KM bulk shear
around 40 KTS, so there is the potential for a severe storm or
two. Also there is some potential for a few areas of locally heavy
rain, as the GFS indicates a couple rounds of precipitation,
perhaps 1/2 to 1 inches in places. The EC models is more
conservative, with lower rainfall amounts generally 1/4 inch or
less.

While strong lift is not indicated Sunday into Monday with
passage of the upper trough, instability along with low/mid level
moisture up to 800 mb will remain over the region. Put in a slight
chance of showers and thunderstorms Sunday into Monday.

04

FIRE WEATHER...
Elevated fire weather conditions across much of the area today,
as the strong winds persist. Dry air mass in place this morning,
and will remain dry through the day. Low level moisture will
actually increase through the day with the southerly flow, and
this may well keep the dry air mass from being so dry that it hits
red flag criteria. In any case, afternoon humidities in the 20% to
25% range will be common. Strongest wind speeds will be this
morning as the low level jet mixes down, but should be stay fairly
strong into the afternoon as well. With both humidity values and
wind speeds right at critical thresholds, opted to hold off on a
Red Flag Warning for now and monitor. If wind speeds are higher in
the afternoon than expected or low level moisture fails to
increase, a Warning will be necessary.

07

&&

.PRELIMINARY POINT TEMPS/POPS...
Abilene  75  52  66  51  73 /   0   0  20  10  10
San Angelo  74  53  74  54  77 /   0   0  10  10  10
Junction  71  54  72  56  77 /   0   5  10  10  10

&&

.SJT WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING until 7 PM CDT this evening FOR THE FOLLOWING
ZONES: Fisher...Haskell...Jones...Nolan...Throckmorton.

&&

$$




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