000
FXUS64 KSJT 150051
AFDSJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
751 PM CDT TUE MAY 14 2013

.UPDATE...
A COMPLEX OF PSEUDO ORGANIZED CONVECTION CONTINUES TO MOVE EAST
INTO THE CWA THIS EVENING. THE STRONGEST STORM IN REAGAN COUNTY
LOOKS MARGINALLY SEVERE WITH SUPERCELLULAR CHARACTERISTICS BUT
SHOULD BEGIN A WEAKENING TREND OVER THE NEXT HOUR AS IT BECOMES
OUTFLOW DOMINANT AND SURFACE BASED CINH INCREASES. ADDITIONAL
CONVECTION IS ONGOING ACROSS THE WESTERN BIG COUNTRY NORTH INTO
THE SOUTH PLAINS FROM NEAR LAMESA TO GUTHRIE.

ALL OF THIS ACTIVITY WILL MOVE EAST THIS EVENING AHEAD OF THE
POTENT CLOSED CYCLONE EXITING SONORA /MEXICO/ WITH MESOSCALE
ENHANCEMENT VIA WEAK SURFACE CONVERGENCE AND THE THERMALLY
INDIRECT CIRCULATION OF A 90 KT H25 SPEED MAX. POPS WERE INCREASED
ACROSS THE WESTERN 1/3 OF THE CWA AND WX TYPE WAS CONVERTED TO
AREAL QUALIFIERS.

JOHNSON

&&

.PREV DISCUSSION... /ISSUED 554 PM CDT TUE MAY 14 2013/

DISCUSSION...
SEE AVIATION DISCUSSION BELOW...

AVIATION...
SHOWERS AND THUNDERSTORMS ARE DEVELOPING JUST WEST OF WEST CENTRAL
TEXAS AT THIS TIME...AND SHOULD APPROACH OUR TERMINALS BETWEEN 01Z
AND 04Z THIS EVENING. FOR NOW...I HAVE KEPT A VCTS MENTION...AS THE
EXACT TIMING OF ANY OF THESE THUNDERSTORMS IS HARD TO
PINPOINT...BUT I WILL AMEND AS NEEDED THROUGHOUT THE EVENING. ANY
STORMS THAT DO MOVE OVER THE TERMINALS MAY CAUSE A BRIEF REDUCTION
IN CEILINGS AND VISIBILITIES...AS WELL AS GUSTY WINDS. STRATUS
DEVELOPMENT IS EXPECTED EARLY WEDNESDAY AT ALL TAF SITES...WITH
MVFR CONDITIONS EXPECTED. VFR CONDITIONS SHOULD RETURN TO ALL TAF
SITES BY MID TO LATE MORNING. SOUTH WINDS OF 10 TO 15 KNOTS
OVERNIGHT WILL INCREASE AT ALL TAF SITES AROUND MID MORNING
WEDNESDAY.

PREV DISCUSSION... /ISSUED 349 PM CDT TUE MAY 14 2013/

SHORT TERM...
.THROUGH WEDNESDAY...
MAIN CHALLENGE IN THE SHORT TERM WILL BE RAIN CHANCES THIS EVENING
INTO WEDNESDAY. CONVECTION HAS ALREADY FIRED OVER THE HIGHER TERRAIN
TO OUR SOUTHWEST THIS AFTERNOON. A WEAK UPPER LOW CURRENTLY OVER
WESTERN CHIHUAHUA AND ITS ASSOCIATED TROUGH AXIS EXTENDING NORTH
ACROSS WEST TEXAS WILL AID IN ADDITIONAL SHOWER AND THUNDERSTORM
DEVELOPMENT TO OUR WEST THIS AFTERNOON. HIRES MODELS SHOW THIS
ACTIVITY DEVELOPING INTO A SMALL CONVECTIVE COMPLEX AS IT MOVES
EAST ACROSS MAINLY OUR SOUTHERN COUNTIES DURING THE EVENING HOURS.
INCREASED POPS TO 40 PERCENT ROUGHLY SOUTH OF A SAN ANGELO TO
BROWNWOOD LINE FOR THIS EVENING. A FEW STRONG TO SEVERE STORMS WILL
BE POSSIBLE SOUTH OF THIS LINE WITH LARGE HAIL AND DAMAGING WINDS
THE MAIN THREAT. FARTHER NORTH...CONVECTION SHOULD BE MORE LIMITED
SO KEPT POPS IN THE SLIGHT CHANCE TO LOW END CHANCE RANGE.

CONSIDERABLE LOW CLOUD DEVELOPMENT IS EXPECTED ACROSS MUCH OF
THE AREA LATE TONIGHT INTO WEDNESDAY MORNING BUT WILL SCATTER OUT
BY MID TO LATE MORNING. THE UPPER LOW WILL HAVE MOVED INTO OKLAHOMA
BY WEDNESDAY AFTERNOON AND COULD RESULT IN ADDITIONAL SHOWER AND
THUNDERSTORM DEVELOPMENT ACROSS MAINLY NORTHERN AND EASTERN SECTIONS.
A MORE CONDITIONAL THREAT FOR THUNDERSTORM DEVELOPMENT WILL EXIST
ACROSS WESTERN SECTIONS DURING PEAK HEATING AS A DRYLINE MIXES EAST
TO OUR WESTERN BORDER. IF STORM DEVELOP...A FEW COULD BE SEVERE
AND POSE A LARGE HAIL AND DAMAGING WIND THREAT INTO THE EVENING
HOURS. OVERNIGHT LOWS TONIGHT WILL BE IN THE 60S WITH HIGHS ON
WEDNESDAY RANGING FROM THE MID AND UPPER 80S EAST TO THE LOWER 90S
WEST.

LONG TERM...
KEEPING A SLIGHT CHANCE OF THUNDERSTORMS WEDNESDAY EVENING...IN
NORTHWEST FLOW ALOFT...AS UPPER TROUGH EXITS EAST. BEST CHANCES
OF RAIN WILL BE OVER THE EASTERN BIG COUNTRY AND HEARTLAND. WITH
GFS SB CAPES OF 2500 J/KG AND 30 TO 40 KTS 0-6 KM SHEAR...COULD
SEE A FEW SEVERE THUNDERSTORMS.

HEAT WILL BE THE MAJOR ISSUES THURSDAY AND FRIDAY...THE AS UPPER
TROUGH MOVES EAST AND AN 850 MB THERMAL RIDGE BUILDS IN FROM THE
WEST. HOTTEST TEMPERATURES WILL BE ALONG AND WEST OF A DRYLINE
FROM HASKELL TO ABILENE TO SAN ANGELO TO SONORA...WHERE HIGHS MAY
APPROACH 100 DEGREES. FIRE WEATHER WILL BE ELEVATED THURSDAY
AFTERNOON... WEST OF THE DRY LINE...AS GUSTY SOUTH SOUTH WINDS
COMBINE WITH RH VALUES BELOW 20 PERCENT.

HAVE SLIGHT CHANCE OF THUNDERSTORMS SATURDAY EVENING...AS AN
UPPER TROUGH MOVES OVER. OTHERWISE IT APPEARS CAPS SHOULD HOLD
OVER THE REGION THIS WEEKEND...WITH 700 MB TEMPERATURES AT OR
ABOVE 12C. WEAK COLD FRONT TRIES TO MOVE INTO THE NORTHERN BIG
COUNTRY TUESDAY...BUT RAIN CHANCES LOOK BLEAK NEXT WEEK AS THE
UPPER RIDGE INTENSIFIES.

04

&&

.PRELIMINARY POINT TEMPS/POPS...
ABILENE  67  88  69  97  69 /  40  20  20  10   5
SAN ANGELO  67  91  69  99  68 /  60  20  20   5   5
JUNCTION  68  86  71  93  69 /  40  20  20   5   5

&&

.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

25/99