Area Forecast Discussion
Issued by NWS San Angelo, TX
FXUS64 KSJT 110412
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
1112 PM CDT MON MAR 10 2014
Areas of stratus are beginning to move into parts of the Interstate
10 corridor and should reach both KJCT and KSOA by 06z. The stratus
is forecast to reach the rest of the sites by 10z, although I have
kept it out of KABI, as they should be on the edge of the cloud
cover. The stratus will result in MVFR to possibly IFR ceilings,
which should become VFR by 14z. South winds of 6 to 12 knots
overnight, will become southwest by mid morning, then west during
the afternoon, at 12 to 18 knots, with higher gusts.
.PREV DISCUSSION... /ISSUED 916 PM CDT MON MAR 10 2014/
The impressive upper-level cyclone over south TX continues to move
to the east this evening and will bring any lingering
precipitation chances to an end as a dry, subsident regime settles
over the region. Skies will be mostly clear this evening, but we
should see low clouds develop after midnight, spreading north
overnight, potentially as far north as I-20. This episode of cloud
cover should be short-lived as westerly winds will advect much
drier/warmer air into West Central TX tomorrow.
Skies will clear by mid-morning with west winds increasing to
15-20 mph (sustained) across the Big Country and Concho Valley
(slightly lower farther southeast). With temperatures warming into
the mid 80s, relative humidities will tumble, falling to near 10
percent during the afternoon hours. While sustained wind speeds
may not quite warrant a Red Flag Warning, we will still see a few
hours of near critical fire weather conditions.
The inherited forecast looks pretty good. I made a few adjustments
to overnight sky conditions but the forecast is generally
unchanged. A new package will be issued in the next hour or so
once precip chances wane.
PREV DISCUSSION... /ISSUED 605 PM CDT MON MAR 10 2014/
The main aviation concern overnight is stratus that is expected to
overspread the area from south to north, after 06z. I expect the
stratus to result in MVFR ceilings at all TAF sites, with brief IFR
conditions possible at mainly KSOA, KJCT, and KBBD. Ceilings will
quickly become VFR between 13z and 15z, with VFR conditions
returning to all sites. South winds overnight of 6 to 12 knots, will
increase to 12 to 18 knots, with higher gusts, by mid to late
PREV DISCUSSION... /ISSUED 350 PM CDT MON MAR 10 2014/
(Tonight and Tuesday)
Widely scattered showers have occurred into this afternoon across
the southern half of our area, in association with an upper low over
northeastern Mexico, beginning to lift into a trough over Texas.
Carrying low POPs this evening and early tonight (before 10 PM)
across the southeastern part of our area, to account for lingering
showers across that area. The upper low will move east into South
Texas tonight, with the upper trough axis also shifting east. Cloud
cover will gradually decrease tonight across central and
southwestern sections of West Central Texas, while cloudiness
lingers across our southeastern counties. With veering low-level
flow and the advection of much drier air into West Central Texas,
expect a rapid breakup of low cloud cover by mid-morning Tuesday.
Much warmer and drier conditions are expected on Tuesday with
increased southwest to west winds, as a surface trough moves east
across West Central Texas. The attendant fire weather threat is
discussed in the Fire Weather Section below. Afternoon highs will be
in the lower to mid 80s.
(Tuesday night through next Monday)
Windy conditions expected Tuesday night, turning much cooler on
Wednesday. Dry conditions will continue through next weekend.
The main concern will be a strong cold front that will plow
through the area Tuesday evening. Models agree that this front
will enter the Big Country around sunset Tuesday, then race south
across the area through the evening hours. Strong pressure rises
behind the front will contribute to very windy conditions areawide
Tuesday night, with sustained winds 25 to 35 mph with gusts 45 to
50 mph likely. At this time, a wind advisory looks like a slam
dunk for the entire area Tuesday night but will hold off on
issuance at this time since the event is more than 24 hours
Breezy and cooler conditions will occur on Wednesday with
temperatures only reaching the upper 50s for afternoon highs.
Winds will be strongest in the morning hours but will begin to
subside by afternoon with the gradient relaxing as surface high
pressure moves into the area. Light winds and cold temperatures
will occur Wednesday night with overnight mainly in the lower
The rest of the extended period will continue dry with moderating
temperatures through Saturday. A weak cold front is expected to move
across the area next Sunday. We`ll see near normal temperatures on
Thursday, above normal temperatures Friday and Saturday and near
normal temperatures behind the front on Sunday.
Elevated fire weather conditions are expected Tuesday afternoon
across all of West Central Texas, with near critical conditions
across the area roughly north of a line from Mertzon to Eden to
Brownwood. Across this area, afternoon relative humidity values will
drop into the range of 8-15 percent, as temperatures climb into the
lower to mid 80s. In addition, west winds will be 15-20 mph with
possible gusts of 25-30 mph. At this time, think that wind speeds
will not be sustained at critical thresholds for more than brief
intervals, so holding off with a Fire Weather Watch or Red Flag
Warning. This bears close monitoring, however.
Strong, gusty north winds are expected to follow a cold frontal
passage Tuesday night. Wind gusts over 45 mph could occur.
Anticipate elevated fire weather conditions on Wednesday, due to
gusty north winds continuing through the morning and into early
afternoon, and relative humidity values dropping to between 20 and
30 percent later in the afternoon.
.PRELIMINARY POINT TEMPS/POPS...
Abilene 50 85 42 58 32 / 5 0 0 0 0
San Angelo 49 86 43 59 31 / 10 0 0 0 0
Junction 48 84 46 59 31 / 20 0 0 0 0