020 FXUS64 KFWD 132052 AFDFWD AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 352 PM CDT WED MAY 13 2015 .DISCUSSION... SATELLITE DATA SHOWS A DISTINCT SHORTWAVE TROUGH MOVING NORTHEAST ACROSS WEST TEXAS. A DEEP MOISTURE FETCH EXTENDS FROM NORTHEAST MEXICO NORTHWARD INTO THE SOUTHERN PLAINS. LIFT FROM THE SHORTWAVE COMBINED WITH GOOD MOISTURE HAS LED TO A ROUND OF SHOWERS AND THUNDERSTORMS ACROSS MOST OF THE REGION TODAY. THE MOST INTENSE AREA OF CONVECTION HAS SHIFTED TO THE LEADING EDGE OF THE RAIN SHIELD WHERE INSTABILITY HAS BEEN ON THE INCREASE SINCE LATE MORNING. THESE THUNDERSTORMS WILL HAVE THE BEST POTENTIAL TO PRODUCE HEAVY RAIN...AND THE MOST LIKELY AREA OF FLOODING SHOULD LIKEWISE SHIFT TO THE EASTERN THIRD OF THE REGION DURING THE LATE AFTERNOON-EARLY EVENING HOURS. THERE IS ALSO A LOW-END CHANCE FOR SEVERE THUNDERSTORMS OVER AREAS GENERALLY EAST OF I-35 AND SOUTH OF I-20 WHERE THE BEST INSTABILITY EXISTS...BUT THE MAIN THREAT STILL APPEARS TO BE HEAVY RAIN. DRY SLOTTING IS EVIDENT ON RADAR OVER THE SOUTHWEST COUNTIES WHERE AN ABRUPT BACK EDGE OF THE RAIN SHIELD CAN BE SEEN. THIS WILL CREATE IMPROVING CONDITIONS FROM SOUTHWEST TO NORTHEAST ACROSS A GOOD CHUNK OF NORTH TEXAS LATER THIS AFTERNOON AND EVENING. PRECIPITATION MAY HAVE TROUBLE TAPERING OFF OVER THE FAR SOUTH BASED ON RADAR TRENDS...WHICH INDICATE MORE CONVECTIVE DEVELOPMENT ACROSS THE HILL COUNTRY. THIS ACTIVITY MAY CONTINUE TO AFFECT THE FAR SOUTHERN COUNTIES THROUGH THE EVENING. ALSO...OUR LEADING LINE OF STORMS MAY SLOW DOWN A LITTLE BEFORE IT MOVES EAST OF THE AREA...WHICH COULD ALLOW THE FLOOD POTENTIAL TO PERSIST ACROSS THE EASTERN COUNTIES INTO THE EVENING HOURS. IN THE MEANTIME...MUCH MORE INTENSE CONVECTION HAS DEVELOPED WEST OF THE REGION...IN AN AREA WHERE DESTABILIZATION /ASSOCIATED WITH DRY SLOT CLEARING/ HAS OCCURRED BENEATH THE COOL AIR ALOFT IN THE VICINITY OF THE SHORTWAVE. WE WILL NEED TO KEEP AN EYE ON THESE STORMS AS THEY TRAVEL EAST TOWARDS NORTH TEXAS THIS EVENING. AT THIS TIME...WE FEEL THAT THESE STORMS MAY REACH THE WESTERN COUNTIES LATER IN THE EVENING HOURS...BUT SHOULD BE WEAKENING DURING THAT TIME. FOR THIS REASON...WE HAVE MAINTAINED THE FLASH FLOOD WATCH THROUGH TONIGHT FOR ALL COUNTIES. THE WATCH SHOULD BE ALLOWED TO EXPIRE DURING THE LATE NIGHT HOURS...OR PERHAPS EVEN CANCELLED EARLY IF/WHEN PRECIPITATION COMES TO AN END. THE NEXT WEATHER SYSTEM IS AN UPPER TROUGH CURRENTLY DEVELOPING ALONG THE WEST COAST. WE SHOULD GET A BREAK IN THE ACTIVITY LATE TONIGHT AND DURING THE DAY TOMORROW BETWEEN SYSTEMS. BY TOMORROW EVENING...MODELS ARE INDICATING A SUBTLE SHORTWAVE MOVING QUICKLY NORTHEAST IN THE SOUTHWEST FLOW ALOFT AHEAD OF THE WEST COAST TROUGH. THIS SHOULD BRING AT LEAST A CHANCE OF THUNDERSTORMS TOMORROW EVENING. COVERAGE AND INTENSITY WILL DEPEND ON THE STRENGTH OF THE SYSTEM. AT THIS TIME...THIS FEATURE LOOKS WEAK ENOUGH TO KEEP ANY ACTIVITY THAT DEVELOPS IN THE ISOLATED CATEGORY. SIMILARLY ON FRIDAY...ONLY ISOLATED STORMS ARE ANTICIPATED ASSOCIATED WITH THE DRYLINE. BETTER COVERAGE SHOULD REMAIN TO OUR WEST IN THE VICINITY OF THE BOUNDARY...WITH STORMS WEAKENING AS THEY MOVE INTO OUR WESTERN COUNTIES. THE WEST COAST TROUGH WILL SWING EAST ACROSS THE SOUTHWEST STATES AND INTO THE SOUTHERN PLAINS OVER THE WEEKEND. IT LOOKS LIKE LIFT FROM THE TROUGH WILL ARRIVE DURING PRIME HEATING HOURS SATURDAY AFTERNOON...ALLOWING GOOD COVERAGE OF STORMS ALONG THE DRYLINE OFF TO OUR WEST. THESE STORMS WILL HAVE THE POTENTIAL TO HOLD TOGETHER AS THE PROGRESS EAST ONTO OUR WESTERN COUNTIES SATURDAY EVENING...THEN ACROSS THE REST OF THE REGION SATURDAY NIGHT INTO SUNDAY MORNING. SOME STORMS WILL BE SEVERE WITH LARGE HAIL AND DAMAGING WINDS BEING THE MAIN THREAT...THOUGH A FEW TORNADOES WILL ALSO BE POSSIBLE. THE UPPER LEVEL PATTERN WILL REMAIN FAIRLY PROGRESSIVE NEXT WEEK...WITH CHANCES OF SHOWERS AND STORMS CONTINUING INTO THE EXTENDED PORTION OF THE FORECAST. 30 && .AVIATION... /ISSUED 1243 PM CDT WED MAY 13 2015/ IFR CIGS WITH PREVAILING RAIN WILL CAN BE EXPECTED THIS AFTERNOON AT ALL LOCATIONS AS A LARGE AREA OF PRECIPITATION MOVES EAST ACROSS THE AREA. CONVECTION HAS BEGUN TO INCREASE ALONG THE LEADING EDGE...BUT SO FAR COVERAGE HAS REMAINED FAIRLY LOW. WE WILL INCLUDE A TEMPO GROUP CONTAINING 3 TO 4 HOURS OF LOWER VISIBILITIES WITH THUNDER AND MODERATE RAIN...WITH THE EXPECTATION THAT EMBEDDED CELLS WILL ACCOMPANY THE BROAD SWATH OF STRATIFORM RAIN. ALL ACTIVITY WILL SHIFT EAST OF THE REGION THIS EVENING AS THE SHORTWAVE TROUGH RESPONSIBLE FOR THE ONGOING DEVELOPMENT LIFTS NORTHEAST ACROSS THE SOUTHERN PLAINS. ADDITIONAL ISOLATED CONVECTION IS POSSIBLE LATE AFTERNOON JUST WEST OF THE REGION AS GOOD SURFACE HEATING TAKES PLACE IN THE VICINITY OF THE DRYLINE. THESE STORMS WILL MOVE EAST...BUT SHOULD REMAIN JUST WEST OF TAF LOCATIONS THIS EVENING. OTHERWISE...IFR CIGS SHOULD IMPROVE AS PRECIP ENDS THIS EVENING...BUT WILL REDEVELOP OVERNIGHT AND CONTINUE THURSDAY MORNING. 30 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 66 83 69 83 70 / 50 30 20 40 30 WACO, TX 67 83 69 83 71 / 30 30 20 40 30 PARIS, TX 65 81 67 80 68 / 60 40 20 40 30 DENTON, TX 66 81 68 82 69 / 50 30 20 40 30 MCKINNEY, TX 66 81 68 82 69 / 60 30 20 40 30 DALLAS, TX 66 83 70 83 70 / 50 30 20 40 30 TERRELL, TX 67 82 69 84 69 / 60 30 20 40 30 CORSICANA, TX 68 82 69 83 69 / 60 30 20 40 30 TEMPLE, TX 67 83 69 83 70 / 30 30 20 40 30 MINERAL WELLS, TX 64 82 67 83 68 / 30 20 30 40 30 && .FWD WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL 1 AM CDT THURSDAY FOR TXZ091>095-100>107- 115>123-129>135-141>148-156>162-174-175. && $$ 30