Area Forecast Discussion
Issued by NWS San Angelo, TX
FXUS64 KSJT 090448
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
1148 PM CDT THU OCT 8 2015
Expect challenging flight weather conditions to continue across
MUCH OF West Central Texas for at least the remainder of tonight.
Rain showers and a few thunderstorms will continue, mainly south
of a line from Sweetwater to Mason. Rain, heavy at times, may
temporarily reduce the visibility to somewhere between 1 and 2
statute miles tonight. For tomorrow, showers and thunderstorms
are possible; however, look for VFR conditions.
.PREV DISCUSSION... /ISSUED 624 PM CDT THU OCT 8 2015/
Look for challenging flight weather across most of West Central
Texas for at least the next 12 hours. An upper-level storm system
is producing showers and thunderstorms across much of West Texas
this evening. Models indicate this activity will continue through
at least tonight. Although ceilings at most terminals will remain
well above the MVFR threshold, the Sonora terminal will likely
have MVFR ceilings for at least several more hours.
PREV DISCUSSION... /ISSUED 348 PM CDT THU OCT 8 2015/
(Tonight and Friday)
The strong upper-low to our west is now beginning to move to the
southwest toward the Baja Peninsula. Several impulses are noted on
water vapor; one is moving across the region this afternoon with
another expected to lift northeast across the Big Bend tonight. A
broad, diffluent upper-level pattern exists downstream of this low,
with a 250mb speed max approaching the Big Bend at this time. The
ingredients are in place for heavy rainfall across southwest TX.
However, it looks like the bulk of this heavy rain will remain to
the south and west of San Angelo. The heaviest rainfall has been
over Reagan County, where MRMS data indicate 4-6 inches of rain so
far today. Other locally heavy amounts have been noted in Crockett
and Sterling Counties. MLCAPE values across the western portion of
the CWA are generally around 1000 J/kg with effective shear
approaching 30 kts. This could result in marginally organized storms
moving out of the Trans-Pecos region.
Additional isolated convection is developing farther east from near
San Angelo to Junction. This activity should become a bit more
widespread this evening and tonight as the aforementioned jet streak
and shortwave approach. That said, we should have a fairly tight
gradient in rainfall amounts across the area with much of the CWA
remaining well under 1/4 inch. Additional amounts over the southwest
zones may exceed 1-2 inches. Expect convection to persist through
Friday morning, favoring the I-10 corridor, before becoming more
scattered during the afternoon hours. Rainfall amounts on Friday are
expected to remain much lower.
Low temperatures tonight are forecast to be in the low to mid 60s
with highs on Friday generally in the low to mid 80s.
(Friday night through next Thursday)
As the upper low retrogrades further into the eastern Pacific, a
mid/upper level ridge will build over Texas and into the
southwestern states this weekend. This will result in dry
conditions with a warming trend for our area. Highs will be in the
mid to upper 80s on Saturday, with partly cloudy skies. Looks very
warm on Sunday with south to southwest low-level flow, mostly
clear skies and 850mb thermal ridge building into our area.
Leaning toward the warmer GFS MOS guidance with highs in the lower
to mid 90s expected Sunday.
An upper trough will traverse the Midwest and Great Lakes on Monday,
with trailing portion of associated cold front moving south across
West Central Texas. This front should arrive soon enough to limit
high temperatures to the mid to upper 80s across our northern
counties, with lower 90s for the southern part of our area. Surface
pressure rise field behind this front suggests several hours of
gusty north-northeast winds following the frontal passage Monday
afternoon and evening.
Cooler air will follow passage of this front, but will be short-
lived. An upper ridge will be over the southwestern states into
Texas Wednesday and Thursday. This will maintain a dry forecast
scenario with high temperatures expected to be around 10 degrees
above normal for that time period.
.PRELIMINARY POINT TEMPS/POPS...
Abilene 63 85 60 87 / 30 30 10 5
San Angelo 64 84 61 88 / 60 40 10 10
Junction 66 86 62 88 / 50 40 10 5