Area Forecast Discussion
Issued by NWS San Angelo, TX

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FXUS64 KSJT 221159

659 AM CDT Fri May 22 2015

/12Z TAFS/

Widespread stratus and reduced visibilities will continue across
the terminals through the forecast period. IFR/LIFR conditions
this morning should lift to MVFR briefly this afternoon but will
deteriorate again this evening. The best chance for showers will
be across the KABI terminal this morning. While showers and a few
thunderstorms will be possible tonight, confidence concerning
timing and coverage remain too uncertain to mention at this time.


.PREV DISCUSSION... /ISSUED 445 AM CDT Fri May 22 2015/

(Today and Tonight)

Another cloudy and cool day is on tap for the area today as the
shallow cold dome remains in place. Temperatures, however, will be
a little warmer today, with highs mainly in the lower and middle
70s. A shortwave trough is currently lifting northeast across New
Mexico and will track across northwest Texas this morning. The best
chance for rainfall will be across the northern counties today, in
association with best lift from the associated shortwave. Carrying
likely POPs north of Interstate 20, with chance POPs elsewhere.

The upper trough will be over the Four Corners region tonight and
will begin moving slowly east towards the area into Saturday. A
warm front will lift north across the area later this evening, with
earnest moisture return expected across the area overnight as a
strong low level jet develops. Height falls overspreading West
Texas will result in steepening mid level lapse rates across west
and northwest portions of the area overnight, with a corresponding
increase in instability. Convection is expected to increase to our
west this evening in response to another weak impulse lifting
northeast across the area. The best chance for storms will be across
northwest sections overnight, with a few strong to severe storms
possible. The mains severe threat overnight will be large hail and
damaging winds, along with the potential for locally heavy rainfall.
The greatest risk for severe storms will be generally be north and
west of a Sterling City to Haskell line.

(Saturday through Friday)

An upper trough over the Southwest U.S. will bring in strong mid
level lift beginning early Saturday morning. With GFS SB CAPES of
1500 to 2000 J/KG in the afternoon and 40 to 50 KT 0-6 KM shear.
Some severe storms possible with large hail, damaging winds, and
isolated tornadoes. Widespread convection and cloud cover, however,
may also act to limit instability and severe potential. The main
threat Saturday may be flooding due to locally heavy rainfall, as
precipitable water increases to 1.5 to 1.8 inches. A flash flood
may be needed Saturday as soils are saturated by recent heavy

A similar setup is in store for Sunday, with stronger heating
potentially bringing enhanced severe potential. 500-700 Lapse
rates increase to 8.0 C/KM in western sections of the Big Country
and Concho Valley by 18Z Sunday, along with CAPES of 2000-2500

Showers and thunderstorms should become more isolated Sunday
night and Monday, as the upper trough moves northeast and drier air
moves into the mid levels. Additional upper troughs, however, will
approach from the West, Monday night into Tuesday, and Wednesday
night into Thursday. These will keep storm chances going into the
end of the week.


Abilene  74  67  78  65  82 /  50  30  70  70  50
San Angelo  76  68  80  66  84 /  40  30  70  70  30
Junction  76  69  80  67  82 /  30  30  60  70  50




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