AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE FORT WORTH TX
1132 PM CDT FRI MAY 24 2013
.AVIATION...
SHOWERS AND MAYBE A FEW THUNDERSTORMS WILL AFFECT THE METROPLEX
AIRPORTS THROUGH 08-09Z. AFTER THE SHOWERS/THUNDERSTORMS
END...SOME MVFR CEILINGS MAY TRY TO WORK THEIR WAY INTO THE
REGION. THUS HAVE PLACED A BKN020 IN THE METROPLEX TAFS FROM
11-16Z. LIGHT RAIN AT KACT SHOULD END AROUND/SHORTLY AFTER 06Z
AND SOME LOW END END MVFR /BKN010/ MAY DEVELOP 10-16Z. THESE
CEILINGS SHOULD LIFT TO VFR AFTER 16Z. ISOLATED SHOWERS AND
THUNDERSTORMS ARE POSSIBLE SATURDAY AFTERNOON NEAR ANY OF THE TAF
SITES SO HAVE KEPT VCTS BETWEEN 19Z AND 00Z IN ALL OF THE TAF
SITES.
58
&&
.UPDATE...
UPDATED THE POPS FOR 00-06Z TIME FRAME TO ACCOUNT FOR CURRENT
RADAR TRENDS. OUTFLOW BOUNDARY FROM THE LARGE COMPLEX OF STORMS
CONTINUES TO PUSH EAST...ALLOWING NEW DEVELOPMENT OF STORMS ALONG
THE BOUNDARY. A COUPLE OF SEVERE STORMS DEVELOPED IN HILL AND
JOHNSON COUNTIES...WHERE WINDS IN EXCESS OF 60 MPH WERE LIKELY. THIS
NEW DEVELOPMENT TO THE EAST SHOULD BECOME LESS LIKELY AFTER
SUNSET...WHEN ACTIVITY SHOULD START TO WANE. WILL CARRY LIKELY POPS
FOR MUCH OF THE WESTERN AREA...WITH CHANCE POPS FARTHER EAST.
HAMPSHIRE
&&
.PREV DISCUSSION... /ISSUED 348 PM CDT FRI MAY 24 2013/
12Z UPPER AIR ANALYSIS SHOWED A WELL-DEFINED MID-LEVEL LOW
PRESSURE SYSTEM NEAR SAN ANGELO THIS MORNING. VISIBLE SATELLITE
IMAGERY AND REGIONAL RADARS INDICATE THAT THIS LOW WAS MOVING
SLOWLY TO THE NORTHEAST THIS AFTERNOON WITH A NEARLY SOLID BAND OF
SHOWERS AND THUNDERSTORMS EXTENDING FROM BRECKENRIDGE SOUTH
THROUGH AUSTIN ON ITS EASTERN EDGE. ACCORDING TO A 19Z AIRCRAFT
SOUNDING AROUND THE DFW AREA THE ATMOSPHERE REMAINS LARGELY
UNCAPPED THIS AFTERNOON WITH 1500 TO 2500 J/KG OF CAPE AVAILABLE
FOR STORM GROWTH.
THROUGH TONIGHT....ASIDE FROM THE MID-LEVEL LOW MOVING TOWARDS
THE CWA...THE LARGER SCALE FLOW REGIME ALOFT OVER NORTH TX IS
ANTICYCLONIC FLOW IN WEAK RIDGING IN PLACE OVER THE REGION. THIS
HAS LEFT A MODERATE CAPE/VERY LOW SHEAR ENVIRONMENT IN PLACE OVER
NORTH TX WHICH IS MORE OF A RAIN PATTERN WE SEE IN THE SUMMER
MONTHS. DUE TO THE VERY WEAK SHEAR IN PLACE AND LITTLE CAP...THINK
A SINGLE CELL TO MULTICELL STORM MODE WILL CONTINUE THROUGH THE
EVENING HOURS WITH A MARGINAL SEVERE WEATHER THREAT IN THE FORM OF
HAIL UP TO QUARTER SIZE AND DOWNBURST WINDS OF 60 MPH. LOCALLY
HEAVY RAINFALL MAY END UP BEING THE BIGGEST HAZARD WHEREVER STORMS
TRAIN OVER ANY ONE LOCATION FOR A COUPLE OF HOURS. THE THREAT FOR
HEAVY RAIN AND FLOODING IS EXPECTED TO REMAIN LOCALIZED THROUGH
THIS EVENING AND WILL NOT BE ISSUING ANY FLOOD OR FLASH FLOOD
WATCH WITH THIS FORECAST PACKAGE. WITH THE LOSS OF DAYTIME
HEATING...MOST HIGH RESOLUTION GUIDANCE AGREES IN A SHARP DOWNWARD
TREND TO THE COVERAGE AND INTENSITY OF STORMS ASSOCIATED WITH THE
MID-LEVEL LOW.
SATURDAY...THE MID-LEVEL LOW PRESSURE SYSTEM MAY BE ENHANCED BY
THIS AFTERNOON AND THIS EVENINGS THUNDERSTORM ACTIVITY ONGOING
ACROSS WESTERN COUNTIES OF NORTH AND CENTRAL TX. BECAUSE THE MID-
LEVEL LOW WAS CREATED BY THUNDERSTORM ACTIVITY YESTERDAY...IT
SEEMS REASONABLE TO ASSUME THAT THIS FEATURE WILL REMAIN AT LEAST
AS STRONG AS IT WAS TODAY AND SHOULD SUPPORT SOME THUNDERSTORM
CHANCES ACROSS NORTH TX TOMORROW. AS A RESULT LEFT IN A MENTION OF
THUNDERSTORMS ACROSS ALL OF NORTH TX THROUGH TOMORROW EVENING. AT
THIS TIME LEFT PRECIPITATION CHANCES AT 20 PERCENT BECAUSE THE
MID-LEVEL LOW MAY BE RIGHT ON TOP OF THE CWA...WHERE SUBSIDENCE
AND POOR MID-LEVEL LAPSE RATES ARE LIKELY TO RESIDE. THE MID-LEVEL
LOW IS WARM CORE...AND DOES NOT CONTRIBUTE TO DESTABILIZING THE
ATMOSPHERE AS A RESULT. WITH GENERALLY CLOUDY SKIES ASSOCIATED
WITH THE LOW AND WEAKER MID-LEVEL LAPSE RATES...INSTABILITY IS
EXPECTED TO BE MUCH WEAKER THAN IT WAS TODAY ACROSS NORTH TX WHICH
WILL LIKELY LIMIT THE AMOUNT OF THUNDERSTORM ACTIVITY THAT WE SEE.
STILL CANNOT RULE OUT ISOLATED STORMS ACROSS THE CWA...ESPECIALLY
DURING THE PEAK HEATING HRS OF THE DAY. WITH MANY OUTDOOR
ACTIVITIES LIKELY TO BE ONGOING DURING THE START OF MEMORIAL DAY
WEEKEND...ISOLATED STORMS PRODUCING LIGHTNING AND LOCALLY GUSTY
WINDS CAN STILL BE HAZARDOUS AND SHOULD BE TAKEN SERIOUSLY. THIS
IS ESPECIALLY TRUE IF YOU HAPPEN TO HAVE PLANS OUT ON AREA LAKES
AND RESERVOIRS THIS WEEKEND.
SUNDAY AND MONDAY...THE MID-LEVEL LOW IS EXPECTED TO MEANDER EAST
IN WEAK RIDGING ALOFT LEAVING SUBSIDENCE IN PLACE OVER NORTH TX.
SUBSIDENCE SHOULD HELP GET RID OF THE 70S DEW POINTS WE HAVE HAD
IN PLACE THE PAST SEVERAL DAYS...ALTHOUGH WE WILL REMAIN WARM
UNDER MOSTLY SUNNY SKIES. WITH SLIGHTLY DRIER AIR IN
PLACE...EXPECT MONDAY TO BE A FEW DEGREES WARMER THAN SUNDAY TO
FINISH OFF MEMORIAL DAY WEEKEND. CHANCES FOR THUNDERSTORMS LOOK
LOW FOR NOW ASSUMING SUBSIDENCE DOES ITS JOB IN DRYING OUT THE
LOWER TROPOSPHERE AND PLACING A CAPPING INVERSION OVER THE REGION.
MID-WEEK...FOR TUESDAY AND WEDNESDAY...THE GFS AND ECMWF AGREE
THAT WE TRANSITION TO SOUTHWEST FLOW ALOFT AS A LARGE UPPER TROUGH
BUILDS OVER THE WESTERN CONUS. THE LARGE TROUGH OUT WEST IS
SOMEWHAT COMPLEX AND COMPOSED OF SEVERAL LARGE SHORTWAVES...BUT AT
LEAST THROUGH WEDNESDAY IT SEEMS THAT MODEL CONSENSUS KEEP THE
BULK OF THIS STRONG ENERGY NORTH OF THE REGION. SOUTHWEST FLOW
ALOFT USUALLY ADVECTS A STOUT ELEVATED MIXED LAYER OVER THE
REGION...AND THIS IS EXPECTED TO HELP KEEP US DRY THROUGH
WEDNESDAY DESPITE THE RESURGENCE OF STRONG SOUTHERLY LOW-LEVEL
FLOW AND GOOD GULF MOISTURE RETURN.
ON THURSDAY...WENT AHEAD AND REINTRODUCED 20 POPS INTO THE
FORECAST BECAUSE THE ECMWF HAS BEEN CONSISTENT IN BRINGING A
STRONG SHORTWAVE TROUGH OVER THE SOUTH PLAINS. THE GFS DOES NOT
SUPPORT THIS...BUT IN GENERAL HAS OFFERED A WIDER SPREAD OF
SOLUTIONS REGARDING THIS UPPER TROUGH WHEN COMPARED TO THE ECMWF.
WHILE THAT DOES NOT GUARANTEE THE ECMWF WILL VERIFY...AT THIS
POINT WANTED TO SIDE WITH THE MORE CONSISTENT SOLUTION WHICH WOULD
BRING A GOOD CHANCE OF STORMS BACK INTO NORTH TX LATE NEXT WEEK.
SHOULD THIS VERIFY...SOME SEVERE STORMS WOULD BE POSSIBLE BUT IT
IS MUCH TOO FAR OUT TO WORRY ABOUT THAT RIGHT NOW. WHEN CONFIDENCE
IN THE LARGE SCALE FLOW IS LOW...CONFIDENCE IN SMALLER SCALE
DETAILS LIKE SEVERE STORM HAZARDS IS EXTREMELY LOW. WILL CONTINUE
TO WATCH LATE NEXT WEEK IN FUTURE FORECASTS.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 67 84 69 86 70 / 60 20 20 5 5
WACO, TX 65 84 68 88 70 / 60 20 20 5 0
PARIS, TX 65 84 67 84 67 / 30 20 20 10 5
DENTON, TX 64 83 67 86 70 / 60 20 10 5 5
MCKINNEY, TX 65 85 68 86 68 / 60 20 20 5 5
DALLAS, TX 68 87 72 88 70 / 60 20 20 5 0
TERRELL, TX 66 87 69 88 68 / 60 20 20 5 0
CORSICANA, TX 66 85 69 88 69 / 60 20 20 5 0
TEMPLE, TX 65 83 68 86 70 / 60 20 20 5 0
MINERAL WELLS, TX 63 82 67 87 69 / 60 20 10 5 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
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