Hail and Damaging Wind in Texas, May 9, 2008

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE FORT WORTH TX
738 PM CDT FRI MAY 9 2008

.UPDATE...
738 PM CDT

BRIEF UPDATE TO ACCOUNT FOR LEFT-MOVING SUPERCELL APPROACHING
LAMPASAS COUNTY. ADJUSTMENTS TO POPS/WX IN SOUTH...BUT STORM
MAINTENANCE IS LARGELY DIURNALLY DRIVEN...AND EXPECT ACTIVITY TO
WIND DOWN BY 03Z. OTHER EDITS TO SHORT-TERM GRIDS TO ACCOUNT FOR
CURRENT TRENDS. UPDATE OUT NOW...WEB IMAGES AND OTHER PRODUCTS
BEING SENT NOW. 25

&&

.AVIATION...
605 PM CDT

AVIATION WEATHER CONCERNS ACROSS THE METROPLEX TAF SITES WILL BE
MINIMAL TONIGHT WITH VFR CONDITIONS AND A NORTH TO NORTHEAST WIND
BETWEEN 6 AN 10 KNOTS. WACO WILL REMAIN VERY NEAR A STALLED
FRONTAL BOUNDARY THIS EVENING AND WILL HAVE A SMALL POTENTIAL FOR
THUNDERSTORMS...BUT FEEL THE CHANCE IS TOO SMALL TO INCLUDE IN THE
TAF. THE FRONT WILL LIFT NORTHWARD OVERNIGHT AND LOW LEVEL
MOISTURE WILL QUICKLY RETURN TO THE REGION. WACO SHOULD SEE MVFR
CEILINGS/ VISIBILITY RETURN NEAR OR JUST AFTER DAYBREAK. THE
METROPLEX TAF SITES MAY SEE A FEW LOW CLOUDS SHORTLY AFTER SUNRISE
BUT MOST OF THE LOW CLOUDS SHOULD REMAIN SOUTH OF THE REGION. A
DRY LINE WILL PUSH INTO NORTH TEXAS DURING THE DAY SATURDAY WITH
SOUTHERLY WINDS BECOMING MORE SOUTHWESTERLY AND INCREASING.

SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG AND AHEAD OF
THE DRY LINE  DURING THE AFTERNOON.  IT APPEARS THE BEST INSTABILITY
WILL BE JUST EAST OF THE METROPLEX TAF SITES SO WILL NOT INCLUDED IN
THIS TAF PACKAGE...BUT WILL INCLUDE A PROB GROUP FOR THUNDER IN WACO
BETWEEN 19 AND 23Z WHEN LIFT SHOULD BE MAXIMIZED.

&&

.PREV DISCUSSION...
351 PM CDT

A WEAK FRONT HAS STALLED ACROSS THE SOUTHERN CWA WITH A VERY
UNSTABLE AIRMASS DEVELOPING ALONG AND SOUTH OF THE BOUNDARY.
OBJECTIVE ANALYSIS INDICATES THAT CIN IS WEAKENING AND WE DO
EXPECT THE CAP TO BREAK BEFORE 6 PM ACROSS CENTRAL TEXAS. ISOLATED
SEVERE STORMS WILL BE THE RESULT...WITH LONG/STRAIGHT HODOGRAPHS
SUGGESTIVE OF SPLITTING SUPERCELLS. AM WORRIED ABOUT LEFT MOVING
SUPERCELLS WANDERING NORTH INTO THE POST FRONTAL AIRMASS AND WILL
CARRY 20 POPS AS FAR NORTH AS A TEMPLE TO ATHENS LINE. STORMS
SHOULD DIMINISH WITH LOSS OF HEATING THIS EVENING.

SHORTWAVE ACROSS THE INTERMOUNTAIN WEST WILL EJECT OUT INTO THE
PLAINS SATURDAY WITH SOUTHERLY WINDS RETURNING TO THE REGION. THIS
WILL TRANSPORT GULF MOISTURE WITH DEWPOINTS NEAR 70 DEGREES
NORTHWARD OVERNIGHT AND INTO TOMORROW MORNING. A DRY LINE WILL MIX
EASTWARD AND REACH THE I-35 CORRIDOR AS LOW PRESSURE ACROSS
OKLAHOMA CAUSES LOW LEVEL WINDS TO VEER TO THE SW AND AID IN
DOWNSLOPE SUBSIDENCE. TEMPERATURES WILL WARM INTO THE MID TO UPPER
90S ACROSS THE W AND SW CWA AS LOW LEVEL THERMAL PROFILES SOAR.
THIS WILL CREATE AN EXTREMELY UNSTABLE ENVIRONMENT OVER THE
EASTERN HALF OF THE CWA WHERE CAPES OVER 3000 J/KG WILL BE COMMON.
THE STRONG HEATING AND WEAK FORCING ALONG THE SOUTHERN FRINGE OF
THE SHORTWAVE TROUGH SHOULD BE SUFFICIENT TO BREAK THE CAP. STORMS
ARE EXPECTED TO DEVELOP ALONG THE DRY LINE AROUND MID AFTERNOON
AND MOVE E/NE. MODELS OFTEN HAVE A BIAS OF BEING TOO FAST WITH THE
EASTWARD PROGRESSION OF DRY LINES...AND THIS MAY ESPECIALLY BE
TRUE ACROSS THE SOUTHERN CWA TOMORROW. FOR THIS REASON...EXPECT
CONVECTIVE INITIATION TO OCCUR ALONG A LINE FROM SHERMAN TO
ARLINGTON TO WACO TO KILLEEN. ANYWHERE ALONG AND EAST OF THIS
LINE...LARGE HAIL...DAMAGING WINDS AND ISOLATED TORNADOES WILL BE
POSSIBLE. POPS WILL GENERALLY RANGE FROM SLIGHT CHANCE ALONG THE
I-35 CORRIDOR AND INCREASE TO 40 PERCENT OVER THE EASTERN ZONES.

A COLD FRONT WILL MOVE THROUGH SATURDAY NIGHT AND BRING MUCH
COOLER CONDITIONS WITH BREEZY NORTH WINDS FOR SUNDAY. SUNDAY NIGHT
WILL BE ESPECIALLY COOL WITH IDEAL RADIATIONAL COOLING PARAMETERS
IN PLACE...AND ISOLATED POCKETS OF 40S POSSIBLE IN OUTLYING
AREAS. A MODERATION WILL OCCUR MONDAY AND INTO TUESDAY AS ANOTHER
MUCH STRONGER SYSTEM DROPS INTO THE SOUTHERN ROCKIES. 12Z
GFS/ECMWF/MREF ARE IN MUCH BETTER AGREEMENT WITH THE TRACK OF THIS
SYSTEM EVEN THOUGH THEY HAVE SLOWED THE TIMING DOWN SLIGHTLY.
THERE WILL BE A DRY LINE FLIRTING WITH THE WESTERN CWA TUESDAY
AFTERNOON...BUT THE BETTER CHANCES OF RAIN LOOK LIKE TUESDAY NIGHT
AND WEDNESDAY. SEVERE WEATHER WILL BE POSSIBLE...BUT THE SPECIFICS
ARE STILL DEBATABLE. WILL CLEAR THE POPS OUT WEDNESDAY NIGHT AS
ANOTHER STRONG FRONT MOVES ACROSS.

LATE NEXT WEEK...GFS/ECMWF SHOWING A HIGHLY AMPLIFIED PATTERN
WHICH WILL TRANSPORT COOL AIR INTO THE REGION. GFS WANTS TO BRING
ANOTHER SHORTWAVE DOWN IN NW FLOW FRIDAY...BUT ECMWF DOES NOT AND
WILL KEEP POPS AT 10 PERCENT FOR NOW.

TR.92

&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  69  92  57  77  52 /  10  20  10   0   0
WACO, TX              69  95  61  80  50 /  20  20  10   0   0
PARIS, TX             63  87  56  74  48 /  10  20  40   0   0
DENTON, TX            66  92  55  78  47 /  10  20  10   0   0
MCKINNEY, TX          63  89  56  78  45 /  10  30  20   0   0
DALLAS, TX            70  91  58  78  53 /  10  20  20   0   0
TERRELL, TX           66  89  60  77  50 /  10  30  30   0   0
CORSICANA, TX         69  91  63  78  52 /  10  30  30   0   0
TEMPLE, TX            69  94  62  81  53 /  20  30  10   0   0

&&

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

79/25/06/20

HAZARDOUS WEATHER OUTLOOK FOR NORTH TEXAS
NATIONAL WEATHER SERVICE FORT WORTH TX
249 PM CDT FRI MAY 9 2008

TXZ091>095-100>107-115>123-129>135-141>148-156>162-174-175-101100-
ANDERSON-BELL-BOSQUE-COLLIN-COMANCHE-COOKE-CORYELL-DALLAS-DELTA-
DENTON-EASTLAND-ELLIS-ERATH-FALLS-FANNIN-FREESTONE-GRAYSON-HAMILTON-
HENDERSON-HILL-HOOD-HOPKINS-HUNT-JACK-JOHNSON-KAUFMAN-LAMAR-LAMPASAS-
LEON-LIMESTONE-MCLENNAN-MILAM-MILLS-MONTAGUE-NAVARRO-PALO PINTO-
PARKER-RAINS-ROBERTSON-ROCKWALL-SOMERVELL-STEPHENS-TARRANT-VAN ZANDT-
WISE-YOUNG-
249 PM CDT FRI MAY 9 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH TEXAS.

.DAY ONE...TODAY AND TONIGHT.
ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE LATE THIS AFTERNOON AND
EARLY THIS EVENING ALONG AND SOUTHEAST OF A LINE FROM TEMPLE TO
ATHENS. DAMAGING WINDS AND LARGE HAIL ARE THE PRIMARY SEVERE WEATHER
THREATS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.
THERE IS A CHANCE OF THUNDERSTORMS SATURDAY AFTERNOON AND EVENING
MAINLY EAST OF INTERSTATE 35. GIVEN THE FORECAST INSTABILITY AND
SHEAR PROFILES...LARGE HAIL...DAMAGING WINDS AND ISOLATED TORNADOES
WILL BE POSSIBLE.

THERE WILL ALSO BE A SLIGHT CHANCE OF THUNDERSTORMS TUESDAY
AFTERNOON THROUGH WEDNESDAY NIGHT. SOME OF THE STORMS MAY BE SEVERE.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE REQUESTED ALONG AND SOUTHEAST OF A TEMPLE
TO ATHENS LINE BETWEEN 4 PM AND 9 PM.