National Weather Service Raw Text Product

Displaying AFOS PIL: AFDFWD Received: 2012-04-04 09:11 UTC


448 
FXUS64 KFWD 040911
AFDFWD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
411 AM CDT WED APR 4 2012

.DISCUSSION...

SEE BELOW FOR A BRIEF DISCUSSION ABOUT YESTERDAY/S TORNADO
OUTBREAK AND TODAY/S PLANNED STORM SURVEYS.

A LARGE UPPER LOW WAS STILL LOCATED TO OUR NORTHWEST THIS MORNING
AND WILL BE MOVING EAST TODAY. AREAS OF DENSE FOG HAVE DEVELOPED
MAINLY ALONG AND EAST OF THE I-35 CORRIDOR WITH DENSE FOG BEING
REPORTED AT SEVERAL SITES ALONG THE I-35 CORRIDOR. A DENSE FOG
ADVISORY WAS ISSUED EARLIER TONIGHT AND WE ANTICIPATE THAT PARTS
OF THE ADVISORY WILL BE CANCELED THROUGHOUT THE MORNING AS THE
TRUE COLD FRONT MOVES THROUGH. AT 4 AM...THE FRONT WAS MOVING INTO
OUR NORTHWESTERN COUNTIES...BUT A GRAVITY WAVE WAS DETECTED ON
SATELLITE AHEAD OF THE FRONT. VISIBILITIES MAY TEMPORARILY IMPROVE
AS THE GRAVITY WAVE MOVES THROUGH BUT FOG MAY ALSO TEMPORARILY
REDEVELOP BEHIND THE PASSING WAVE.

AS THE UPPER LEVEL LOW MOVES INTO EASTERN OKLAHOMA THIS
EVENING...SOME OF THE ENERGY MOVING AROUND THE LOW WILL GRAZE
ACROSS THE NORTHERN AND NORTHEASTERN COUNTIES OF THE CWA. WE COULD
SEE A FEW SHOWERS AND POSSIBLY ISOLATED THUNDERSTORMS DEVELOP AS
THIS POTENT LOW PASSES TO OUR NORTH. FORECAST SOUNDINGS INDICATE
DRY AIR IN THE LOW AND MID LEVELS MAY ONLY RESULT IN VIRGA...BUT
WILL CARRY LOW POPS MAINLY ALONG AND NORTH OF I-20 TONIGHT. SEVERE
WEATHER IS NOT EXPECTED WITH THIS ACTIVITY...HOWEVER...WILL NOT
COMPLETELY RULE OUT SOME SMALL HAIL POSSIBLE IN TALLER STORMS GIVEN
THE COLD TEMPERATURES ASSOCIATED WITH THE LOW.

UPPER LEVEL RIDGING WILL BUILD IN ACROSS NORTH TEXAS ON THURSDAY
AND PERSIST THROUGH THE END OF THIS FORECAST PERIOD. THE UPPER
LEVEL RIDGE WILL FLATTEN SOME THIS WEEKEND AS A POTENT TROUGH
MOVES THROUGH THE NORTHERN PLAINS. UNDERNEATH THE UPPER LEVEL
RIDGE...SEVERAL FRONTS WILL REACH THE REGION OVER THE NEXT SEVEN
DAYS. THE FIRST FRONT WILL QUIETLY SLIDE INTO NORTH TEXAS LATE ON
THURSDAY...WITH THE NEXT FRONT ARRIVING LATE ON SATURDAY OR
SATURDAY NIGHT...AND THEN ANOTHER FRONT EARLY NEXT WEEK. THERE IS
A SLIGHT CHANCE FOR RAIN WITH THE FRONT THIS WEEKEND AND EARLY
NEXT WEEK...BUT MOST OF THE FORCING WILL COME FROM THE FRONTS
THEMSELVES DUE TO A LACK OF LARGE SCALE FORCING. AT THIS
TIME...SEVERE WEATHER IS NOT ANTICIPATED WITH EITHER OF THESE
FRONTS. THERE ARE SLIGHT MODEL DISCREPANCIES REGARDING THE TIMING
OF THE FRONTS AND THE FORECASTED ARRIVALS AND POPS MAY BE
ADJUSTED.

TEMPERATURES THIS WEEK WILL CONTINUE TO AVERAGE ABOVE NORMAL BUT
WILL BE PLEASANT. DAYTIME HIGHS WILL MOSTLY BE IN THE UPPER 70S TO
LOWER 80S BUT SOME SLIGHTLY COOLER TEMPERATURES ARE POSSIBLE
BEHIND NEXT WEEK/S FRONT. OVERNIGHT LOWS WILL VARY BUT WILL
GENERALLY BE IN THE 50S TO LOWER 60S.

82/JLD

/APRIL 3RD TORNADO OUTBREAK/
SURVEY TEAMS WILL BE HEADING OUT EARLY TO ASSESS THE DAMAGE THAT
OCCURRED ACROSS NORTH TEXAS YESTERDAY FROM THE TORNADIC
SUPERCELLS. APPROXIMATELY 11-13 AREAS OF DAMAGE HAVE BEEN REPORTED
AND WILL BE SURVEYED TODAY AND ON THURSDAY IF NEEDED. IT IS
UNKNOWN AT THIS TIME EXACTLY HOW MANY TORNADOES THERE WERE AND THE
SURVEY TEAMS TODAY WILL BE WORKING TO DETERMINE A MORE CONCRETE
NUMBER. INFORMATION ABOUT THE SURVEYS WILL BE DISSEMINATED
THROUGHOUT THE DAY THROUGH OUR WEBPAGE AND FACEBOOK PAGE AS THE
SURVEY TEAMS INVESTIGATE THE DAMAGE. A MORE COMPLETE WRITE-UP WILL
LIKELY NOT BE ISSUED UNTIL LATE THIS EVENING.

AT THIS TIME YESTERDAY...ALL EVIDENCE WAS SUGGESTING THE EVENT  
WOULD BE A FAIRLY TYPICAL SPRING SEVERE WEATHER DAY ACROSS
NORTH TEXAS. IT WAS ANTICIPATED THAT A LINE OF SEVERE STORMS
WOULD FORM AROUND MIDDAY AND MOVE EAST ACROSS PART OF THE REGION.
THE POTENTIAL FOR TORNADOES WAS DISCUSSED BUT IT WAS THE MESOSCALE
FEATURES THAT PLAYED A SIGNIFICANT ROLE IN WHAT ENDED UP BEING AN
OUTBREAK ACROSS NORTH TEXAS. IT APPEARS AN OUTFLOW BOUNDARY FROM 
STORMS OVER OKLAHOMA EARLY TUESDAY MORNING ENDED UP BEING A KEY 
PLAYER IN ENHANCING THE TORNADO THREAT. THIS OUTFLOW BOUNDARY PUSHED 
SOUTH ACROSS THE RED RIVER YESTERDAY MORNING AND REACHED THE 
INTERSTATE 20 CORRIDOR BEFORE STALLING. DISCRETE SUPERCELLS MANAGED 
TO FORM AHEAD OF THE DEVELOPING LINE OF STORMS. AS THESE SUPERCELLS 
MOVED NORTH AND CROSSED THE OUTFLOW BOUNDARY...THEY ENTERED AN 
ENVIRONMENT WITH INCREASED LOW LEVEL SHEAR DUE TO EASTERLY SURFACE 
WINDS. IT WAS ALSO NOTED BY LOCAL REAL TIME MODELING THAT THE SURFACE 
TO 3KM CAPE WAS VERY HIGH IN THE AREAS WHERE THE TORNADOES OCCURRED. 
A LINK BETWEEN INCREASED LOW LEVEL CAPE AND TORNADOES HAS BEEN FOUND 
IN PREVIOUS RESEARCH. MORE IN DEPTH STUDY AND ANALYSIS WILL LIKELY
BE DONE ON THIS DAY IN THE NEAR FUTURE. THIS WAS A GOOD EXAMPLE
OF HOW SMALL MESOSCALE FEATURES CAN QUICKLY CHANGE THE STORM
ENVIRONMENT ON ANY GIVEN DAY WHEN SEVERE WEATHER IS ANTICIPATED. 
UNFORTUNATELY IT IS STILL VERY DIFFICULT IF NOT IMPOSSIBLE FOR THE 
MODELS TO RESOLVE THESE SMALL MESOSCALE FEATURES...AND IT IS WHY WE 
URGE EVERYONE TO PAY ATTENTION TO THE WEATHER ON DAYS WHEN SEVERE 
WEATHER IS EXPECTED.

82/92

&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  76  56  79  59  82 /  10  20   0   0   0 
WACO, TX              81  56  80  57  82 /  10  10   0   0   0 
PARIS, TX             75  53  75  53  77 /  10  30   5   0   0 
DENTON, TX            75  53  79  55  81 /  10  30   0   0   0 
MCKINNEY, TX          75  53  77  55  80 /  10  30   5   0   0 
DALLAS, TX            76  57  80  60  82 /  10  20   0   0   0 
TERRELL, TX           75  55  78  57  80 /  10  20   5   0   0 
CORSICANA, TX         78  57  79  58  81 /  10  10   5   0   0 
TEMPLE, TX            83  58  81  57  84 /  10  10   0   0   0 
MINERAL WELLS, TX     76  50  80  54  82 /  10  10   0   0   5 

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR TXZ104-
118>121-130>134-143>146-157>161.


&&

$$

92/82