175
FXUS64 KSJT 220450
AFDSJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
1150 PM CDT TUE MAY 21 2013
DISCUSSION
/SEE BELOW FOR AVIATION DISCUSSION/
AVIATION
LOW/MID LEVEL MOISTURE RETURN INDICATED BY THE NAM MODEL MID
MORNING ALONG I-10 AS A WARM FRONT MOVES BACK NORTH. THE GFS
MODEL HOWEVER IS MUCH DRIER WITH 850 MB MOISTURE JUST BEGINNING
AROUND 18Z. THE GFS HAS BEEN BETTER AT HANDLING LIMITED LOW CLOUD
RETURN THIS YEAR... PERHAPS DUE TO DROUGHT CONDITIONS OVER THE
REGION...SO WILL ONLY BRING IN A SCATTERED 5000 FT LAYER AROUND
NOON.
04
PREV DISCUSSION
/ISSUED 951 PM CDT TUE MAY 21 2013/
UPDATE...
QUICK UPDATE TO DECREASE CLOUD COVER OVERNIGHT.
DISCUSSION...
THE COLD FRONT IS NOW WELL SOUTH OF THE AREA WITH A DRIER
AND MORE STABLE AIRMASS FILTERING INTO THE AREA FROM THE NORTH.
SURFACE HIGH PRESSURE WILL BUILD INTO THE AREA OVERNIGHT WITH
LIGHT WINDS AND MOSTLY CLEAR SKIES EXPECTED. DECREASED SKY COVER
THIS UPDATE AND MADE MINOR TWEAKS TO WINDS...TEMPERATURES AND
DEWPOINTS TO REFLECT CURRENT TRENDS. TEMPERATURES WILL BE VERY
PLEASANT OVERNIGHT WITH LOWS BY DAYBREAK AROUND 60 DEGREES
AREAWIDE.
PREV DISCUSSION... /ISSUED 615 PM CDT TUE MAY 21 2013/
DISCUSSION...
/SEE BELOW FOR AVIATION DISCUSSION/
AVIATION...
VFR NEXT 24 HOURS. A FEW GUSTS TO 18 KTS UNTIL 1Z...WITH NORTH
WINDS DECOUPLING THIS EVENING. SOUTHEAST WINDS RETURN TUESDAY
MORNING AS SURFACE HIGH PRESSURE MOVES EAST.
PREV DISCUSSION... /ISSUED 545 PM CDT TUE MAY 21 2013/
UPDATE...
THE THREAT FOR SEVERE WEATHER HAS ENDED ACROSS SOUTHEAST COUNTIES
AS THE COLD FRONT HAS EXITED THE AREA. THEREFORE...THE TORNADO
WATCH THAT WAS IN EFFECT FOR SAN SABA...MASON AND KIMBLE COUNTIES
HAS BEEN CANCELED. UPDATED ZONES HAVE BEEN SENT.
PREV DISCUSSION... /ISSUED 259 PM CDT TUE MAY 21 2013/
SHORT TERM...
THE MAIN CONCERN IN THE SHORT TERM IS THE ONGOING CONVECTION
ACROSS THE EASTERN HALF OF WEST CENTRAL TEXAS. A COLD FRONT WAS
LOCATED FROM SOUTH OF SAN ANGELO...TO NEAR BROWNWOOD AND STEADILY
MOVING SOUTH. SCATTERED SHOWERS AND THUNDERSTORMS ARE DEVELOPING
ALONG AND AHEAD OF THE FRONT...GENERALLY EAST OF BALLINGER...TO
BROWNWOOD LINE. SHOWERS AND THUNDERSTORMS MAY CONTINUE TO DEVELOP
ALONG THE BOUNDARY THIS AFTERNOON...AS THE FRONT ENTERS AN
INCREASINGLY UNSTABLE ENVIRONMENT. ANY STORMS...MAINLY SOUTH OF
THE FRONT...THAT DEVELOP WILL HAVE THE POTENTIAL TO BECOME
SEVERE...WITH THE MAIN HAZARDS BEING LARGE HAIL AND DAMAGING
WINDS. WE WILL CANCEL THE TORNADO WATCH FOR AREAS NORTH OF THE
COLD FRONT...LEAVING ONLY KIMBLE...MASON...AND SAN SABA COUNTIES
IN THE WATCH AFTER 3 PM. THE TORNADO WATCH REMAINS IN EFFECT FOR
THOSE LAST THREE COUNTIES UNTIL 7 PM CDT. MOST OF THE CONVECTION
SHOULD BE SOUTH AND EAST OF OUR AREA BY EARLY EVENING...ALTHOUGH A
FEW LINGERING STORMS ARE POSSIBLE...MAINLY ACROSS THE NORTHWEST
HILL COUNTRY. MOST OF THE CONVECTION SHOULD BE WELL SOUTH OF THE
AREA BY MIDNIGHT. AS SKIES CLEAR AND DEWPOINT TEMPERATURES DROP
INTO THE 50S...TEMPERATURES SHOULD FALL INTO THE LOWER 60S TO
UPPER 50S ACROSS MOST OF THE REGION BY DAYBREAK. HIGH TEMPERATURES
ON WEDNESDAY WILL BE A FEW DEGREES ABOVE NORMAL...GENERALLY IN THE
UPPER 80S TO MID 90S. NO RAIN IS IN THE FORECAST FOR WEDNESDAY.
LONG TERM...
THE MAIN ISSUES IN THE LONG TERM FORECAST WILL BE RAIN CHANCES
LATER IN THE WEEK.
BY TUESDAY NIGHT...LOW LEVEL FLOW WILL TURN BACK AROUND TO THE
SOUTHEAST. THIS WILL BRING RICH GULF MOISTURE BACK INTO THE AREA
BY MIDWEEK...ALONG WITH WARMER THAN NORMAL TEMPERATURES. IN
RIDGING WILL DEVELOP ACROSS THE AREA ALOFT WHICH WILL SERVE TO
LIMIT PRECIPITATION CHANCES THROUGH WEDNESDAY IN ADDITION TO
SPEEDING UP THE WARMING TREND. BY THURSDAY INTO FRIDAY...SOUTHWEST
FLOW ALOFT WILL DEVELOP ALONG OUR WESTERN BORDER AND FARTHER WEST.
MEDIUM RANGE MODELS CONTINUE TO DIFFER IN THEIR SOLUTIONS WITH
RESPECT TO THIS PATTERN. THE ECMWF IS MUCH MORE OPTIMISTIC WITH
PRECIPITATION FOR OUR AREA WHEREAS THE GFS KEEPS RAIN CHANCES
ALONG OUR WESTERN BORDER AND WESTWARD. WITHOUT CONFIDENCE IN
THE MODELS ABILITY TO RESOLVE MESOSCALE FEATURES...WILL CONTINUE
TO GO WITH SLIGHT CHANCE POPS MAINLY ALONG OUR WESTERN BORDER FOR
THURSDAY INTO FRIDAY NIGHT. WILL ALSO CONTINUE TO GO WITH
TEMPERATURES SLIGHTLY WARMER THAN THE EXTENDED RANGE MOS GUIDANCE
FROM THE GFS.
PRELIMINARY POINT TEMPS/POPS
ABILENE 59 91 69 94 70 / 5 10 10 10 20
SAN ANGELO 60 94 70 95 70 / 5 5 10 10 20
JUNCTION 62 93 70 93 70 / 10 5 5 0 10
SJT WATCHES/WARNINGS/ADVISORIES
NONE.
99/99/04
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