000
FXUS64 KFWD 170854
AFDFWD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
354 AM CDT FRI MAY 17 2013

.DISCUSSION...
...A FEW SEVERE STORMS POSSIBLE ACROSS FAR WESTERN NORTH TEXAS BY
EACH EVENING TODAY AND SATURDAY...THEN NORTH OF I-20 LATE SUNDAY...

WEATHER FORECAST REMAINS CHALLENGING TODAY INTO THE WEEKEND. WE
CONTINUED TO SEE A SUBTLE SURFACE BOUNDARY SITUATED ALONG/NORTH OF
HWY 38 THIS MORNING AS EVIDENCED BY THE BACKED/LIGHTER EAST WINDS
AND LOWER SURFACE DEW POINTS THIS MORNING...WHILE STRONGER SSE
WINDS 10 TO 15 MPH WHERE OCCURRING FROM THE I-20 CORRIDOR INTO
CENTRAL TEXAS. SOME PATCHY DENSE FOG WAS OCCURRING ALONG THE RED
RIVER VALLEY...WHILE A SUBTLE DISTURBANCE WAS MOVING ACROSS WITHIN
THE UPPER RIDGE OVER THE TOP OF THE AREA. SOME AC/ACCAS WAS NOTED
ON INFRARED SATELLITE IMAGERY WITH STEEP LAPSE RATES ALOFT ON THE
00Z FWD SOUNDING AND MODELS. ISOLATED...ELEVATED/HIGH-BASED
SHOWERS AND STORMS ARE POSSIBLE THIS MORNING MAINLY ALONG AND
SOUTH OF THE I-20/I-30 CORRIDORS. LIGHTNING WILL BE THE MAIN
THREAT WITH ACTIVITY THIS MORNING WITH VERY LITTLE IN THE WAY OF
MEASURABLE RAINFALL EXPECTED.

THE SURFACE DRYLINE AND ASSOCIATED LOW PRESSURE OVER FAR WEST
TEXAS WILL CONTINUE TO DEEPEN AND SLIDE SLOWLY EAST TOWARD OUR FAR
W/SW COUNTIES LATE THIS AFTERNOON/EVE. STRONG MIXING AND HEATING
ALONG AND JUST AHEAD OF THIS FEATURE WILL HELP HIGHS SOAR WELL
INTO THE 90S WITH A FEW AREAS TOPPING THE CENTURY MARK WEST OF
I-35/I-35W. OUR CAPPING INVERSION WAS ELEVATED AND BASED ABOVE
800MB AND NOT OVERLY STOUT...SO DESPITE THE UPPER RIDGE ARRIVING
OVERHEAD...FEEL THE HOT TEMPS WILL MAKE IT BREAKABLE. HIGH-RES
WRF/ARW/AND HRRR MODELS ALL HINT AT ISOLATED STORM DEVELOPMENT JUST
W/SW OF OUR CWA AT PEAK HEATING AND POTENTIALLY AFFECTING OUR FAR
WSW COUNTIES BETWEEN 4 PM AND SUNSET. INSTABILITY WILL BE VERY HIGH
WITH MODELS SHOWING 3500-5000 J/KG SBCAPE OR POSSIBLY MORE WITH
VERY STEEP MID LEVEL LAPSE RATES OVER 8 DEG C/KM. ANY ISOLATED
STORMS THAT OCCUR WILL LIKELY BE SEVERE WITH VERY LARGE HAIL AND
DAMAGING DOWNBURSTS. DESPITE SURFACE DEW POINTS BEING NEAR 70
DEGREES...THE HOT TEMPERATURES WILL RESULT IN RELATIVELY HIGH
BASES AND A LOWER TORNADO THREAT THAN A FEW DAYS AGO. WITH THE
UPPER RIDGE OVERHEAD...STORMS WILL DIMINISH IN STRENGTH OR
DISSIPATE RAPIDLY AROUND SUNSET WITH LOSS OF HEATING AND THE CAP
INTENSIFYING QUICKLY BY LATE EVENING.

THE UPPER RIDGE SHIFTS EAST OF THE AREA ON SATURDAY WITH LONGWAVE
UPPER TROUGH SNAKING OVER THE ROCKIES INTO THE WESTERN HIGH
PLAINS. THE DRYLINE WILL ACTUALLY MAKE A STRONGER PUSH TOWARD OUR
FAR WESTERN COUNTIES BY EARLY EVENING SATURDAY WITH A LITTLE
BETTER UPPER SUPPORT. INSTABILITY WILL BE VERY STRONG ONCE AGAIN
WITH ISOLATED TO SCATTERED STRONG TO SEVERE STORMS EXPECTED MAINLY
ALONG AND WEST OF HWY 281...THEN DIMINISHING QUICKLY AFTER SUNSET
WITH THE CAP INTENSIFYING ONCE AGAIN. THE UPPER TROUGH DAMPENS
OVER THE CONUS ON SUNDAY WITH STRONG WESTERLY FLOW ALOFT OCCURRING
FROM THE RED RIVER VALLEY NORTH THROUGH THE CENTRAL PLAINS. HAVE
MODIFIED BEST CHANCES TO OCCUR NORTH OF I-20 AND INTO THE RED
RIVER VALLEY...WITH THE CAP BEING MUCH STRONGER OVER THE SOUTH.
DIURNAL SEVERE WEATHER WILL BE POSSIBLE AGAIN...BUT CONFIDENCE IS
LOWER FOR LATE SUNDAY DUE TO UNCERTAINTIES REGARDING CAP STRENGTH
AND SOUTHERN EXTENT OF FORCING. THE BEST SURFACE FOCUS WILL BE
ALONG A COLD FRONT THAT IS EXPECTED TO BE WELL TO THE NORTHWEST OF
THE AREA AS WELL.

OTHERWISE IN THE EXTENDED...STAYED WITH PERSISTENCE WITH THE
PREVIOUS FORECAST WITH LOW POPS RETURNING BY MID WEEK WITH A COLD
FRONT WEAKENING AND STALLING ACROSS THE NORTHWEST COUNTIES. A
SHORTWAVE TROUGH WILL BE MOVING OVER THE CENTRAL AND SOUTHERN
PLAINS AT THIS TIME AS WELL. IT IS TOO EARLY TO ASSESS ANY SEVERE
WEATHER THREAT THIS FAR OUT...BUT WILL CONTINUE TO ASSESS THESE
POSSIBILITIES IN THE COMING DAYS AHEAD.

05/

&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  89  72  93  72  88 /  10  10   5  10  10
WACO, TX              92  71  92  71  90 /  20  10   5  10  10
PARIS, TX             82  68  86  69  86 /  10  10  10  10  10
DENTON, TX            86  70  93  71  89 /  10  10  10  10  20
MCKINNEY, TX          84  69  91  69  88 /  10  10   5  10  10
DALLAS, TX            88  72  93  72  90 /  10  10   5  10  10
TERRELL, TX           89  69  90  70  89 /  10  10   5  10  10
CORSICANA, TX         91  70  91  70  89 /  20  10   5  10  10
TEMPLE, TX            91  70  91  71  89 /  10  10  10  10  10
MINERAL WELLS, TX     94  70  96  70  93 /  10  10  10  10  20

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

05/