528 FXUS64 KLUB 212104 AFDLUB AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LUBBOCK TX 404 PM CDT TUE MAY 21 2013 .SHORT TERM... LARGE-SCALE ASCENT ASSOCIATED WITH A 60-70 KT ULJ ON THE SRN FLANK OF A SHORTWAVE TROUGH MOVING ACROSS THE PANHANDLES IS MAINTAINING SOME MODEST CONVECTION ACROSS THE SRN PANHANDLE AND ROLLING PLAINS THIS MID-AFTERNOON. INSTABILITY IS VERY MEAGER...SBCAPES UNDER 200 J/KG...SO WE BARELY EXPECT THUNDER WITH THIS ACTIVITY. HOWEVER...A MID-LVL COLD POCKET ROTATING SWD AROUND THE WRN FLANK OF THE TROUGH IS INCREASING MID-LVL INSTABILITY ACROSS NE NM AND THE WRN PANHANDLES WITH SBCAPES ANALYZED TO AROUND 500 J/KG. THIS AREA WILL PROGRESS SEWD TOWARD THE FA LATE THIS AFTERNOON AND EVENING AND AS A RESULT WE COULD SEE ANOTHER BATCH OF SHOWERS/TSTMS DEVELOP AND MOVE SEWD TOWARD MAINLY OUR NRN ZONES. LIMITED MOISTURE SHOULD KEEP THE ACTIVITY ISOLATED TO WIDELY SCATTERED. AN ISOLD STRONG STORM WITH SMALL HAIL IS NOT OUT OF THE QUESTION UNTIL THE BOUNDARY LAYER BEGINS TO STABILIZE AROUND SUNSET. SFC RIDGING WILL BRING LIGHT WINDS OVERNIGHT WITH SEASONABLY COOL TEMPS. THEN FOR WEDNESDAY...A RETURN TO SRLY WINDS AND AN UPPER RIDGE APPROACHING FROM THE WEST SHOULD RESULT IN WARMER TEMPS...RIGHT AROUND 90F EXPECTED FOR MANY LOCATIONS. SHALLOW MOISTURE WILL MIX OUT ACROSS THE CAPROCK. MOISTURE WILL LIKELY BE SUFFICIENTLY DEEP TO GENERATE SOME POTENTIAL INSTABILITY IN THE ROLLING PLAINS...BUT THE ATMOSPHERE IS EXPECTED TO REMAIN CAPPED WITH BUILDING HEIGHTS ALOFT. && .LONG TERM... INITIALLY PROGRESSIVE FLOW REGIME WILL TREND MORE BLOCKY LATER THIS WEEK IN RESPONSE TO LONGWAVE RIDGING EMERGING FROM THE CENTRAL GREAT PLAINS ALL THE WAY NORTH TO THE OIL SANDS OF FORT MCMURRAY, ALBERTA. FORTUNATELY...THE SOUTH PLAINS OF TEXAS WILL FALL UNDER THE SUBTROPICAL JET RESIDING SOUTH OF THE REGION OF STRONG HEIGHT RISES. THIS RIDGE WILL EDGE SLOWLY EASTWARD THROUGH THE HOLIDAY WEEKEND SUBJECTING THE CWA TO SOUTHWEST UPPER FLOW DOWNSTREAM OF A SEMI-STATIONARY TROUGH OVER THE WESTERN CONUS. UPSHOT OF THIS IS AN INCREASINGLY ACTIVE PATTERN FOR OUR DOMAIN BEGINNING THURSDAY BEFORE THE MEAN DRYLINE BECOMES SITUATED WEST OF THE 100TH MERIDIAN THEREAFTER...ULTIMATELY GIVING OUR FRIENDS IN OKLAHOMA A MUCH-NEEDED BREAK FROM THEIR RECENT RASH OF SEVERE WEATHER. BIGGEST FORECAST CHALLENGE FOR THE NEXT WEEK IS THIS THURSDAY AND CONCERNS THE THREAT FOR SIGNIFICANT SEVERE CONVECTION. DESPITE THE 500MB RIDGE AXIS DIRECTLY OVER THE SOUTH PLAINS...THIS AREA IS UNDER A RELATIVE WEAKNESS IN THE RIDGE AS THE SUBTROPICAL JET WILL BE OVER THE REGION. AMPLE MOISTURE CURRENTLY IN CENTRAL TX WILL BE CHANNELED WEST-NORTHWEST WED AFTERNOON AND OVERNIGHT LEADING TO RICH PWATS BY THURSDAY AHEAD OF A DRYLINE AND CRUCIAL FRONTAL BOUNDARY PROGGED TO BACKDOOR SLOWLY ACROSS THE TX PANHANDLE. HAVE KEPT TIMING OF THIS FRONT ON TRACK WITH EARLIER FORECASTS FAVORING STRONG LL CONVERGENCE OVER OUR N-NERN COUNTIES BY PEAK HEATING. FORECAST SOUNDINGS ARE NOTHING SHORT OF IMPRESSIVE FOR ORGANIZED SEVERE MODES INCLUDING SUPERCELLS. LOCATION OF THE FRONT WILL PROVE CRITICAL FOR A TORNADIC THREAT AS 0-3KM HELICITIES NEAR THIS BOUNDARY ARE SHOWN TO REACH IN EXCESS OF 300 M2/S2. DID ADD SEVERE MENTION AND LOCALLY HEAVY RAIN LATE THURSDAY FOR THE NERN QUARTER OF OUR CWA NEAR THIS BOUNDARY WHERE STRONG CAPE AND PWATS AOA ONE INCH APPEAR LIKELY. THEREAFTER...GULF MOISTURE WILL REMAIN INTACT OVER MUCH OF THE CWA WITHIN SUSTAINED S-SELY 850MB FLOW. DAILY DRYLINE POSITION THROUGH AT LEAST EARLY NEXT WEEK FAVORS THE NM STATE LINE AREA WITH PERHAPS DAILY CHANCES FOR TSTORMS...BUT FOR NOW HAVE ENDED MENTION AFTER SUNDAY NIGHT GIVEN THIS IS OVER FIVE DAYS OUT. HOWEVER...THE UPPER FLOW DOES MAINTAIN A FAVORABLY UNSETTLED SWLY MID-LEVEL FLOW THAT COULD CERTAINLY WARRANT DAILY DRYLINE STORMS. BARRING CONVECTIVE DEBRIS...TEMPS LOOK TO HOLD WITHIN 5 DEGS OR SO OF SEASONABLE AVERAGES THROUGH THE PERIOD. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 50 87 57 87 58 / 10 0 10 20 30 TULIA 53 88 59 87 61 / 10 0 10 30 30 PLAINVIEW 53 88 61 88 63 / 10 0 10 30 40 LEVELLAND 53 90 63 90 63 / 0 0 10 20 30 LUBBOCK 55 90 64 90 65 / 10 0 10 20 40 DENVER CITY 54 90 64 94 64 / 0 0 10 20 20 BROWNFIELD 54 92 65 91 64 / 0 0 10 20 20 CHILDRESS 55 90 63 89 64 / 10 10 10 50 50 SPUR 55 90 63 91 66 / 0 10 10 20 40 ASPERMONT 58 93 67 93 68 / 10 10 10 20 40 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 33/93