674 FXUS64 KLUB 181744 AFDLUB AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LUBBOCK TX 1244 PM CDT SAT MAY 18 2013 .AVIATION... EXPECT VFR CONDITIONS TO REMAIN AT THE TERMINALS THIS TAF CYCLE...WITH BREEZY SOUTH TO SOUTHWESTERLY WINDS THIS AFTERNOON AND BREEZY WESTERLY WINDS TOMORROW AFTERNOON. KCDS WILL HAVE AN OUTSIDE CHANCE OF A STORM LATE THIS AFTERNOON INTO EARLY THIS EVENING...BUT PROSPECTS OF A DIRECT IMPACT ARE TOO LOW TO INCLUDE IN THE TAF ATTM. && .PREV DISCUSSION... /ISSUED 1131 AM CDT SAT MAY 18 2013/ UPDATE... SHORTWAVE TROUGH THAT BROUGHT THE EXCITEMENT IN TERMS OF HEAT BURSTS...SPOTTY LIGHT RAIN AND A FEW ELEVATED STORMS WAS NOW EXITING TO OUR NORTHEAST...WITH THE NEXT UA TROUGH OF CONSEQUENCE APPROACHING THROUGH THE DESERT SOUTHWEST. LIFT WITH THE WESTERN NEGATIVELY TILTED TROUGH WAS INCREASING ACROSS MUCH OF NM AND WILL CONTINUE TO SPREAD EASTWARD THIS AFTERNOON AND TONIGHT. THIS WILL PROVIDE AT LEAST SOME UPPER LEVEL SUPPORT BY PEAK HEATING WITH THE GREATEST UPPER FORCING PROGGED TO MOVE ACROSS LATE TONIGHT. AT THE SFC...SOUTHERLY FLOW HAS DRAWN DEWPOINTS INTO THE LOWER AND MIDDLE 60S ACROSS THE EASTERN ZONES...THOUGH VEERING FLOW WAS ALSO BRINGING IN MUCH DRIER AIR ACROSS THE WESTERN ZONES. IN FACT...HUMIDITIES WERE ALREADY BELOW 10 PERCENT ACROSS THE FAR NORTHWEST ZONES...WHERE COUPLED WITH INCREASING WINDS...THE FIRE DANGER WILL BE HIGH. IT STILL APPEARS THE DRYLINE WILL SHARPEN SOMEWHERE IN CLOSE PROXIMITY TO OUR EASTERN MOST ZONES BY MID TO LATE AFTERNOON. STRONG HEATING/MIXING...WITH HIGHS CLIMBING UP INTO THE TRIPLE DIGITS...COUPLED WITH CONVERGENCE ALONG THE DRYLINE AND WEAK UPPER SUPPORT SHOULD BE ENOUGH TO BREAK THE CAP...WITH ISOLATED TO WIDELY SCATTERED MOIST CONVECTION EXPECTED TO DEVELOP AFTER 20Z. STRONG INSTABILITY EAST OF THE DRYLINE COUPLED WITH SUFFICIENT DEEP LAYER SHEAR WILL ALLOW STORMS TO RAPIDLY BECOME SEVERE...WITH SUPERCELLULAR MODES LIKELY. RELATIVELY HIGH LCLS AND RATHER WEAK 0-1 KM SHEAR WOULD SUGGEST LARGE HAIL AND DAMAGING WIND GUSTS WILL BE THE PRIMARY MODE WITH THE INITIAL DEVELOPMENT...THOUGH STRONG INSTABILITY COULD COMPENSATE SOMEWHAT AND PROVIDE A LOW TORNADO CHANCE. LOW-LEVEL WIND SHEAR WILL INCREASE THIS EVENING AS THE LOWER WIND FIELDS STRENGTHEN AND BACK AND LCLS GRADUALLY LOWER. BIGGEST QUESTION FOR OUR CWA IS IF AND FOR HOW LONG CONVECTION CAN STAY IN OUR AREA. OF THE GUIDANCE THAT DEVELOPS STORMS IN OUR EASTERN ZONES LATE THIS AFTERNOON...MOST SHOW THE ACTIVITY QUICKLY SHIFTING EAST OF THE FA...WHICH WOULD KEEP OUR WINDOW FOR SEVERE WEATHER QUITE NARROW. THERE MAY BE A RISK FOR REDEVELOPMENT ALONG THE DRYLINE IN OUR FAR EASTERN ZONES LATE TONIGHT AS THE LARGE SCALE SUPPORT PEAKS...THOUGH MOST GUIDANCE DOES NOT SHOW THIS SCENARIO...WITH THE COOLING LOWER ATMOSPHERE REMAINING CAPPED. WEST OF THE DRYLINE...ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS WILL EXIST AND THE RED FLAG WARNING AND FIRE DANGER STATEMENT REMAIN VALID FOR THIS AFTERNOON AND EVENING. THE ONGOING FORECAST HAD A GOOD HANDLE ON ALL OF THIS AND ONLY MINOR TWEAKS WERE MADE THIS MORNING. PREV DISCUSSION... /ISSUED 517 AM CDT SAT MAY 18 2013/ SHORT TERM... TWO BANDS OF VERY LIGHT VIRGA SHOWERS CONTINUE MOVING NORTHEAST ACROSS THE FAR SOUTHEASTERN TEXAS PANHANDLE AND ROLLING PLAINS THIS MORNING. THIS IS DUE TO A WEAK UPPER LEVEL DISTURBANCE MOVING THROUGH ALONG WITH A LOW LEVEL JET INTERACTING WITH THE DRYLINE. THIS SHOULD WRAP UP BY SUNRISE BEFORE THE MERCURY STARTS TO CLIMB AGAIN. DEEP MIXING WILL OCCUR AS SKIES CLEAR FROM WEST TO EAST THIS MORNING AND LEAD TO HIGHS IN THE MID 90S ACROSS THE NORTHWEST TO THE LOW 100S INTO THE ROLLING PLAINS. CHILDRESS IS FORECAST TO HIT 101 DEGREES TODAY WHICH WOULD BREAK THE PREVIOUS RECORD OF 99 FOR THE DATE. AN UPPER TROUGH CURRENTLY ENTERING THE GULF OF CALIFORNIA WILL CONTINUE TO SLIDE EAST TODAY AND INCREASE FORCING FOR ASCENT ACROSS THE REGION AS HEIGHTS FALL. THE DRYLINE WILL MIX QUICKLY EAST AHEAD OF THIS FEATURE...POSSIBLY MIXING EAST OF THE ROLLING PLAINS THIS AFTERNOON. HOWEVER...A DEEPENING SURFACE LOW ACROSS THE TEXAS/OKLAHOMA PANHANDLES SHOULD KEEP THE DRYLINE WITHIN REACH SO THAT IT RETREATS BACK ACROSS THE ROLLING PLAINS AND EXTREME SOUTHEAST PANHANDLE THIS EVENING. DEEP LAYER SUPPORT WILL BE MAXIMIZED THIS EVENING AND EARLY TONIGHT AS THE PREVIOUSLY MENTIONED NEGATIVELY TILTED TROUGH SWINGS INTO SOUTH CENTRAL NEW MEXICO. AN INTENSIFYING LOW LEVEL JET WILL ALSO DEVELOP AND USHER IN RICHER MOISTURE AHEAD OF THE DRYLINE...LENGTHENING HODOGRAPHS AND STRENGTHENING SHEAR PROFILES TO SUPPORT ORGANIZED UPDRAFTS. EVEN THOUGH COVERAGE MAY BE LIMITED...BELIEVE WHAT DOES DEVELOP WILL BE STRONG TO SEVERE...CAPABLE OF PRODUCING LARGE HAIL...GUSTY WINDS TO 60 MPH...AND AN ISOLATED TORNADO. STORM ROOTS WILL BECOME INCREASINGLY ELEVATED AS SURFACE COOLING COMMENCES POST-SUNSET...LEADING TO MORE OF A HAIL THREAT AS THE EVENING WEARS ON. CONDITIONS WILL DRY OUT AFTER MIDNIGHT AS THE TROUGH AND SURFACE LOW PUSH EAST AND PULL DRIER AIR ACROSS THE AREA. LONG TERM... AN ACTIVE WEATHER PATTERN IN STORE DURING THE NEXT WEEK WHICH SOME EXCITEMENT INTO NEXT WEEKEND...MORE ON THAT LATER. UPPER LEVEL LOW WILL BECOME ESTABLISHED FROM THE NEG TILTED TROUGH ACROSS THE WESTERN USA. THIS LOW WILL UNDERGO MATURATION LATE THIS WEEKEND INTO EARLY NEXT WEEK ACROSS THE NORTH CENTRAL PLAINS WHILE A LOBE OF ENERGY ROTATES AROUND THIS PARENT LOW REACHING THE FOUR CORNERS BY MONDAY AFTERNOON. BY LATE TUESDAY AFTERNOON... NORTHWESTERLY FLOW RETURNS TO THE AREA AS ANOTHER DEEP LOW COMES ASHORE THE PACIFIC NORTHWEST COAST. RIDGING WILL BUILD INTO THE CENTRAL CONUS SERVING TO BLOCK EWRD PROGRESSION OF NORTHWESTERN LOW. ON SUNDAY MORNING...DRYLINE SHOULD START OFF ACROSS OUR EASTERN ZONES THUS LEAVING THE AREA HOT AND DRY. IT WOULD APPEAR THAT ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS WILL OCCUR ONCE AGAIN ON SUNDAY AFTERNOON AS WIND SPEEDS RAMP UP TO THE 20 TO 25 MPH RANGE. NWP IS STRONGER WITH THE LATE SUNDAY COLD FRONT THIS MORNING AND GIVEN THE STRENGTH AND RESULTS OF THIS MORNINGS TROUGH WHICH GENERATED SOME HIGH BASED SHOWER ACTIVITY...THIS NEW FOUND STRENGTH APPEARS PLAUSIBLE. THE NAM IS MOST ASSERTIVE WITH THE PROGRESSION OF THE FEATURE. WHICH BY IN LARGE MAY MAKE IT MOST...BUT PERHAPS NOT ALL THE WAY ACROSS THE CWFA. SURFACE LOW LOOKS TO REMAIN OVER THE EASTERN HALF OF THE AREA ON MONDAY KEEPING THINGS QUITE WARM AND DRY. INTO THE EVENING HOURS...A MUCH MORE PRONOUNCED COLD FRONT MAKES THROUGH WITH THE GFS DEPICTING POST-FRONTAL PRECIPITATION. HOWEVER...THE MODEL APPEARS TOO MOIST AND WILL CONTINUE THE FCST THINKING THAT THIS WILL YIELD YET ANOTHER DRY FRONTAL PASSAGE THOUGH AREAS TO OUR NORTH AND EAST WILL HAVE A BETTER CHANCE OF STORMS. FCST GUIDANCE HAS TRENDED LOWER ON TUESDAY/S HIGH AND GIVEN THE EVOLUTION OF THE SYSTEM...THIS TOO SEEMS REASONABLE AND ADJUST TEMPS COOLER TUE/WED AS A RESULT. INTO LATE WEEK...MORE EXCITING PROSPECTS FOR PRECIPITATION ARE LOOKING TO COME TOGETHER AS PERSISTENT SWRLY FLOW ALOFT ALLOWS INCREASING MOISTURE INTO THE REGION THEN ASSISTED BY A SLUG OF PACIFIC MOISTURE LATE THURSDAY. WITH PWAT VALUES INCREASING UP TO WELL OVER AN INCH THIS LOOKS LIKE IT COULD YIELD THE BEST PROMISE OF MEANINGFUL RAINFALL IN SOME TIME...AND WE`LL TAKE WHAT WE CAN GET! FIRE WEATHER... DAY 1 CRITICAL FIRE WEATHER CONDITIONS WILL DEVELOP WEST OF AN EASTWARD MIXING DRYLINE THIS AFTERNOON. THE PREVIOUSLY ADVERTISED FIRE WEATHER WATCH HAS BEEN UPGRADED TO A RED FLAG WARNING ACROSS WESTERN AND CENTRAL PORTIONS OF THE EXTREME SOUTHERN TEXAS PANHANDLE...SOUTH PLAINS...AND FAR WESTERN ROLLING PLAINS. TEMPERATURES WILL CLIMB INTO THE MID 90S TO NEAR 100 DEGREES WITH MINIMUM RELATIVE HUMIDITIES IN THE SINGLE DIGITS. 20 FOOT WINDS WILL INCREASE TO 20 MPH OR SLIGHTLY ABOVE THUS WARRANTING THE UPGRADE TO A WARNING. WILL ISSUE A RANGELAND FIRE DANGER STATEMENT FOR AREAS JUST EAST OF THOSE IN THE WARNING. DAY 2-3 CRITICAL FIRE WEATHER CONDITIONS WILL BE POSSIBLE ONCE AGAIN SUNDAY AFTERNOON OVER MUCH OF THE SAME AREA COVERED BY THE WARNING THIS MORNING AS DRY CONDITIONS COMBINE WITH BREEZY AFTERNOON WINDS. TO AVOID PRODUCT CONFUSION...WILL HOLD OFF ON SECOND RED FLAG PRODUCT FOR SUNDAY AT THIS TIME. WHILE FIRE WEATHER CONDITIONS MAY EASE ON MONDAY TO SOME EXTENT...ELEVATED TO NEAR CRITICAL CONDITIONS MAY OCCUR DURING THE AFTERNOON AS WELL. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 56 87 54 83 49 / 0 0 0 0 0 TULIA 57 92 56 88 52 / 0 0 0 0 0 PLAINVIEW 57 94 58 89 53 / 0 0 0 0 0 LEVELLAND 59 94 57 90 54 / 0 0 0 0 0 LUBBOCK 59 96 60 91 55 / 0 0 0 0 0 DENVER CITY 60 92 59 90 55 / 0 0 0 0 0 BROWNFIELD 60 95 60 92 55 / 0 0 0 0 0 CHILDRESS 63 95 62 92 58 / 20 0 0 0 0 SPUR 59 98 64 94 60 / 10 0 0 0 0 ASPERMONT 69 99 65 97 62 / 20 0 0 0 0 && .LUB WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING UNTIL 9 PM CDT THIS EVENING FOR THE FOLLOWING ZONES: TXZ021>024-027>030-033>036-039>042. && $$ 23/99/99