094 
FXUS64 KFWD 011201
AFDFWD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
601 AM CST WED FEB 1 2012

.AVIATION...

FOR THE 12Z TAFS...FOG AND LOW STRATUS IN THE FIRST FEW HOURS OF
THE VALID FORECAST PERIOD ARE THE PRIMARY CONCERNS. VFR CONDITIONS
ARE EXPECTED FROM LATE THIS MORNING THRU THE END OF THE FORECAST
PERIOD.

AREAS OF DENSE FOG HAD DEVELOPED ACROSS THE EASTERN HALF OF NORTH
TEXAS EARLY THIS MORNING. THE WORST OF THE FOG WAS RELEGATED TO
KGKY FOR METROPLEX TAF SITES AND KACT REMAINS SOCKED IN WITH 1/4
MILE FOG AT THE TIME OF THIS DISCUSSION. EXPECT IFR CONDITIONS TO
PERSIST AT KGKY THRU 14Z WHEN VEERING WINDS AND THE APPROACH OF A
WEAK COLD FRONT SHOULD BE SUFFICIENT TO DISSIPATE LOWER VSBYS IN
SOUTHERN TARRANT COUNTY. IFR CONDITIONS ARE LIKELY TO PERSIST AT
KACT THRU AT LEAST 15Z. DID NOT EXTEND FLIGHT RESTRICTIONS BEYOND
15Z AT THIS TIME AS KACT REMAINS ON THE WESTERN PERIPHERY OF THE
BANK OF DENSE FOG AND THEREFORE CAN BE EXPECTED TO RESPOND QUICKLY
TO HEATING AFTER SUNRISE. A WEAK FRONTAL BOUNDARY IS EXPECTED TO
PUSH THROUGH NORTH TX A BIT FASTER THAN PREVIOUS FORECAST
INDICATED. LATEST RUC GUIDANCE BRINGS THE FRONT THRU THE METROPLEX
DURING THE EARLY AFTERNOON HRS AND THEN THRU WACO AROUND 21Z.
DRIER AIR BEHIND THE FRONT SHOULD ENSURE VFR CONDITIONS FOR THE
NEXT 24 HRS AT AREA TAF SITES.

CANNOT RULE OUT SOME RAIN SHOWER OR ISOLATED TSTM ACTIVITY ALONG
THE COLD FRONT THIS AFTERNOON. DO NOT HAVE ANY MENTION OF
PRECIPITATION IN THE TAFS AT THIS TIME AS COVERAGE IS EXPECTED TO
BE LIMITED DUE TO MEAGER FORCING FOR ASCENT ALONG THE COLD FRONT.
WILL MONITOR FOR SIGNS OF DEVELOPMENT AND AMEND TAFS IF NECESSARY
THIS MORNING.

CAVANAUGH 

&&


.PREV DISCUSSION... /ISSUED 514 AM CST WED FEB 1 2012/
SHALLOW DENSE FOG DEVELOPED IN THE NEAR-CALM SURFACE LAYER.
ADVISORY COVERS MUCH OF THE AREA WHERE PATCHY DENSE FOG
PERSISTS...BUT SOME SHALLOW FOG WILL CONTINUE ELSEWHERE.

TODAY...
DIFFUSE FRONTAL BOUNDARY REMAINS NEAR NORTHWESTERN EDGE OF CWA.
DESPITE ORIENTATION OF EARLY MORNING CONVECTION...FLOW WITHIN THE
LAYER OF LIFT IS PARALLEL TO THE BOUNDARY. THIS AREA OF RATHER
BENIGN CONVECTION WILL SLOWLY TRANSLATE NORTHEAST INTO NE ZONES
OVER THE COURSE OF THE DAY. FRONT WILL PENETRATE CWA TODAY...AND
THE BOUNDARY WILL INTERACT WITH UNSEASONABLY WARM BOUNDARY LAYER.
AS WINDS PICK UP...THE 60F ISODROSOTHERM WILL MOVE FARTHER
INLAND...RESULTING IN MUCAPE VALUES IN EXCESS OF 1000 J/KG. BUT
WITH MINIMAL LOW-LEVEL CONVERGENCE AND RATHER SHALLOW MOISTURE...
HAVE LOW CONFIDENCE IN WIDESPREAD CONVECTION THIS AFTERNOON. WITH
MESOSCALE MODELS RATHER GUN-SHY...WILL MAINTAIN 20 POPS IN
EAST/SOUTHEAST ZONES.

FRIDAY EVENT...
TROUGH CURRENTLY OVER THE ALEUTIANS WILL QUICKLY DEEPEN AS IT 
ENTRAINS BITTER COLD FROM THE POLAR VORTEX NEAR THE ARCTIC COAST
OF ALASKA. THE RESULTING DOWNSTREAM RIDGE WILL PUSH THE TROUGH
CURRENTLY NEAR THE WEST COAST OF THE CONUS EASTWARD. THE
AMPLIFICATION OF THE RIDGE AS IT REACHES THE WEST COAST WILL ALLOW
THIS TROUGH TO PULL POLAR AIR INTO THE INTERMOUNTAIN WEST...
DEEPENING THE FEATURE INTO A CLOSED LOW AS EARLY AS THURSDAY.

WARM ADVECTION AHEAD OF THE SYSTEM MAY ALLOW SOME SHOWERS
(ISOLATED THUNDER) TO DEVELOP LATE THURSDAY. THE UPGLIDE WILL
INCREASE DRAMATICALLY THURSDAY NIGHT...WITH WIDESPREAD SHOWERS AND
THUNDERSTORMS LIKELY BY DAYBREAK FRIDAY. SIGNIFICANT FORCING WILL
MEAN STRONG CONVECTION COULD ACCOMPANY FROPA LATE FRIDAY...BUT
STILL HAVE CONCERNS THAT PRECIP EARLY IN THE DAY WILL LIMIT
INSTABILITY FOR THE MAIN EVENT. WHILE THERE IS GOOD INTER-MODEL
AGREEMENT INTO FRIDAY ON THE SYNOPTIC SCALE AS GUIDANCE IS ABLE TO
RESOLVE A WELL BEHAVED SYSTEM WITHIN THE POLAR STREAM...IT IS TOO
EARLY TO PERFECT PROG THE MESOSCALE EVOLUTION OF THE EVENT.

WEEKEND...
BY FRIDAY NIGHT...THE POLAR JET CUTS THE LOW OFF...AND SOLUTIONS
DIVERGE AS A RESULT. DESPITE SOME UNCERTAINTY IN FRONTAL TIMING...
WILL CONTINUE TO TAPER OFF POPS FRIDAY NIGHT. TEMPS CLOSER TO
NORMAL WILL PREVAIL THIS WEEKEND. ONCE LOW FINALLY EJECTS...A
REINFORCING SHOT OF COLD AIR WILL INVADE SATURDAY NIGHT AND
SUNDAY. SOME MOIST UPGLIDE WILL BY POSSIBLE EARLY SUNDAY IN
SOUTHERN ZONES...BUT EXPECT THE THIN MOISTURE TO ONLY YIELD A
CLOUD LAYER. MEX GUIDANCE APPEARS TOO BULLISH...WILL MAINTAIN POP-
FREE FORECAST BEYOND FRIDAY NIGHT.

25

&&



.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  75  52  72  61  74 /  10  10  10  50  80 
WACO, TX              74  50  72  59  75 /  10  10  10  50  80 
PARIS, TX             70  52  68  58  72 /  20  10  10  50  80 
DENTON, TX            72  45  70  58  73 /  20  10  10  50  80 
MCKINNEY, TX          72  45  69  56  74 /  20  10  10  50  80 
DALLAS, TX            73  53  72  61  75 /  10  10  10  50  80 
TERRELL, TX           73  52  72  60  73 /  20  10  10  50  80 
CORSICANA, TX         75  55  76  61  74 /  20  10  20  50  80 
TEMPLE, TX            77  52  75  59  73 /  10  10  10  50  70 
MINERAL WELLS, TX     72  44  69  56  71 /  20  10  10  50  80 

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR TXZ094-095-
104>107-120>123-133>135-145>148-158>162-174-175.


&&

$$