Special Weather Statement, NWS Fort Worth, TX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE FORT WORTH TX
1221 PM CDT MON AUG 6 2012

.AVIATION...
CONCERNS THROUGH SUNSET WILL BE ISOLATED STORM DEVELOPMENT AND
BACKING OF WINDS FROM WSW TO SELY BY 00Z TUESDAY.

WEAK SHORTWAVE CONTINUES TO DROP SWD ACROSS E TX WITH A WEAKENING
MORNING STORMS OCCURRING BETWEEN KSLR AND KPSN. ALL TERMINALS ARE
JUST OUTSIDE OF THE HIGH CLOUD CANOPY WILL LIKELY SEE DIFFERENTIAL
HEATING AND AGEOSTROPHIC LIFTING PROCESSES AS THE AFTERNOON
PROGRESSES. THERE ARE INDICATIONS FROM THE RAP AND NORMAN WRF
MODELS THAT ISOLATED STORMS WILL BECOME MORE EVIDENT BY MAX
HEATING OR MID AFTERNOON. WITH A VERY MOIST AND TROPICAL AIRMASS IN
PLACE...PRECIP LOADING COULD RESULT IN GUSTY DOWNBURSTS IN EXCESS
OF 40 KTS POSSIBLE. ONLY DIFFERENCE IS WACO WILL LIKELY SEE THEIR
BEST POTENTIAL LATER IN DAY...BETWEEN 21Z-01Z.

OTHERWISE...VFR FORECAST CONTINUES WITH LIGHT SWLY FLOW BECOMING
SELY BY SUNSET...THEN SWLY BY DAYBREAK TUESDAY.

05/

&&

.UPDATE...
A WEAK BOUNDARY REMAINS ACROSS THE NORTHEASTERN ZONES AT MIDDAY.
THE MAIN CHANGE TO THE FORECAST WAS TO ADD ISOLATED THUNDERSTORMS
TO THE WEST WHERE THE HIGH RESOLUTION RAPID REFRESH IS SHOWING
SOME THUNDERSTORM DEVELOPMENT LATER THIS AFTERNOON. HAVE ALSO
ADJUSTED THE HOURLY TEMPERATURES IN THE NORTHEAST WHERE CLOUD
COVER AND EARLIER PRECIPITATION HAVE SLOWED THE WARM UP.

58

&&

.PREV DISCUSSION... /ISSUED 413 AM CDT MON AUG 6 2012/
NORTH TO NORTHWEST FLOW ALOFT WILL REMAIN OVER NORTH TEXAS THROUGH
THE WEEK AS UPPER LEVEL HIGH PRESSURE REMAINS CENTERED NEAR THE
FOUR CORNERS REGION. THIS PATTERN WILL RESULT IN SEASONALLY HOT
TEMPERATURES AND SOME LOW RAIN/THUNDERSTORM CHANCES THROUGH MUCH
OF THE WEEK.

A WEAK COLD FRONT THAT HAD MOVED INTO NORTH TEXAS ON SUNDAY
WAS LOCATED NEAR A SHERMAN TO SULPHUR SPRINGS LINE EARLY THIS
MORNING. THIS FRONT IS PROGGED TO SLOWLY BACKDOOR THE EASTERN
COUNTIES OF NORTH TEXAS THROUGH TUESDAY. THE FRONT WILL CONTINUE
TO ACT AS A FOCUSING MECHANISM FOR SCATTERED SHOWERS AND
THUNDERSTORMS...ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS.
THERE IS ALSO A SMALL CHANCE THAT SOME SHOWERS AND THUNDERSTORMS
COULD MOVE ACROSS THE WESTERN AND NORTHERN PORTIONS OF NORTH TEXAS
DURING THE OVERNIGHT/MORNING HOURS TONIGHT THROUGH THURSDAY
MORNING...AS AFTERNOON CONVECTION ACROSS THE CENTRAL PLAINS MOVES
SOUTH/SOUTHEAST DURING THE OVERNIGHT HOURS. FOR NOW WE WILL KEEP
ALL POPS LOW WITH ONLY WEAK FORCING EXPECTED AND A VERY DRY
SOLUTION FROM THE ECMWF.

UPPER LEVEL HIGH PRESSURE WILL BUILD BACK TO THE EAST BY THE
WEEKEND WHICH SHOULD DECREASE RAIN CHANCES DUE TO INCREASED LARGE
SCALE SUBSIDENCE.

HIGH TEMPERATURES THROUGH THE WEEK WILL RANGE FROM THE MIDDLE 90S
TO AROUND 101 WITH OVERNIGHT LOWS FROM THE MIDDLE 70S TO NEAR 80.
THE ONLY LOCATIONS THAT WILL SEE AFTERNOON HEAT INDEX VALUES UP TO
106 WILL BE THE EASTERN ZONES DUE TO SLIGHTLY BETTER MOISTURE.
THEREFORE...WILL KEEP THE HEAT ADVISORY THROUGH TUESDAY JUST FOR
THE EXTREME EASTERN COUNTIES OF NORTH TEXAS. HOWEVER...OVERNIGHT
LOWS MAY BE SLIGHTLY SHY OF REACHING CRITERIA IN SOME SPOTS.

79

&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 102  80 101  79 101 /  20  20  10  20  20
WACO, TX             100  77 102  80 100 /  20  20  10  10  20
PARIS, TX             98  76  99  75  98 /  20  20  10  10  20
DENTON, TX           102  77 102  76 101 /  20  10  10  20  20
MCKINNEY, TX          99  76  99  76  99 /  20  20  10  20  20
DALLAS, TX           101  82 101  80 100 /  20  20  10  20  20
TERRELL, TX          100  76 100  76  98 /  20  20  20  20  20
CORSICANA, TX        100  76 100  76  99 /  20  20  20  10  20
TEMPLE, TX           101  76 100  76  99 /  20  10  10  20  20
MINERAL WELLS, TX    101  78 101  78 102 /  10  20  20  20  20

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 8 PM CDT TUESDAY FOR TXZ107-122-123-135-
146>148-160>162-174-175.

&&

05/58

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FORT WORTH TX
317 PM CDT MON AUG 6 2012

TXZ091>095-100>107-115>123-129>135-141>148-156>162-174-175-071200-
MONTAGUE-COOKE-GRAYSON-FANNIN-LAMAR-YOUNG-JACK-WISE-DENTON-COLLIN-
HUNT-DELTA-HOPKINS-STEPHENS-PALO PINTO-PARKER-TARRANT-DALLAS-
ROCKWALL-KAUFMAN-VAN ZANDT-RAINS-EASTLAND-ERATH-HOOD-SOMERVELL-
JOHNSON-ELLIS-HENDERSON-COMANCHE-MILLS-HAMILTON-BOSQUE-HILL-NAVARRO-
FREESTONE-ANDERSON-LAMPASAS-CORYELL-BELL-MCLENNAN-FALLS-LIMESTONE-
LEON-MILAM-ROBERTSON-
317 PM CDT MON AUG 6 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH TEXAS.

.DAY ONE...THROUGH TONIGHT.

THUNDERSTORMS ARE EXPECTED ACROSS ALL OF NORTH TEXAS THROUGH THIS
EVENING...WITH BEST CHANCES NORTH OF A GRAHAM...TO GRANBURY...TO
ATHENS LINE. GUSTY DOWNBURST WINDS TO 50 MPH...FREQUENT LIGHTNING
AND BRIEF HEAVY RAINFALL ARE POSSIBLE WITH STRONGER STORMS. ISOLATED
THUNDERSTORMS REMAIN POSSIBLE ACROSS NORTHWEST TEXAS AFTER MIDNIGHT.

A HEAT ADVISORY REMAINS IN EFFECT ALONG AND EAST OF A SULPHUR
SPRINGS...TO CORSICANA...TO CAMERON LINE.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

A HEAT ADVISORY WILL REMAIN IN EFFECT THROUGH 8 PM TUESDAY EVENING
FOR AREAS SOUTHEAST OF A SULPHUR SPRINGS...TO CORSICANA...TO
CAMERON LINE.

A CHANCE FOR MAINLY AFTERNOON AND EVENING THUNDERSTORMS WILL
CONTINUE ACROSS NORTH TEXAS TUESDAY THROUGH FRIDAY. GUSTY DOWNBURST
WINDS AND LIGHTNING WILL CONTINUE TO BE THE MAIN THREATS EACH DAY.

.SPOTTER INFORMATION STATEMENT...
LIMITED SPOTTER ACTIVATION MAY BE REQUESTED THROUGH SUNSET THIS
EVENING.

05/

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE FORT WORTH TX
319 PM CDT MON AUG 6 2012

TXZ103-062045-
DENTON TX-
319 PM CDT MON AUG 6 2012

...SIGNIFICANT WEATHER ADVISORY FOR...
  NORTHWESTERN DENTON COUNTY

AT 319 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
STRONG THUNDERSTORM 6 MILES NORTHWEST OF DENTON...MOVING SOUTH AT 10
MPH.

CITIES IN THE PATH OF THIS STORM INCLUDE CORINTH...DENTON...KRUM...
SANGER AND SHADY SHORES.

VERY HEAVY RAIN AND WIND GUSTS TO 55 MPH ARE LIKELY WITH THIS STORM.

LAT...LON 3315 9703 3310 9733 3333 9738 3341 9714
TIME...MOT...LOC 2019Z 347DEG 9KT 3326 9722

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE FORT WORTH TX
327 PM CDT MON AUG 6 2012

TXZ093-103-104-062100-
DENTON TX-GRAYSON TX-COLLIN TX-
327 PM CDT MON AUG 6 2012

...SIGNIFICANT WEATHER ADVISORY FOR...
  NORTHWESTERN COLLIN COUNTY
  NORTHEASTERN DENTON COUNTY
  SOUTHWESTERN GRAYSON COUNTY

AT 327 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
STRONG THUNDERSTORM 11 MILES NORTHWEST OF MCKINNEY...MOVING SOUTH AT
15 MPH.

CITIES IN THE PATH OF THIS STORM INCLUDE CELINA...FRISCO...GUNTER...
MCKINNEY AND PROSPER.

VERY HEAVY RAIN AND WIND GUSTS TO 55 MPH ARE LIKELY WITH THIS STORM.

LAT...LON 3348 9666 3324 9654 3313 9684 3325 9697
      3342 9694 3353 9694
TIME...MOT...LOC 2027Z 005DEG 12KT 3332 9678