505  
FXUS64 KLUB 230900  
AFDLUB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LUBBOCK TX  
400 AM CDT WED APR 23 2014  
   
SHORT TERM
 
 
A SHARPENING DRYLINE LATER TODAY IS EXPECTED TO BECOME THE FOCUS FOR  
SCATTERED THUNDERSTORM DEVELOPMENT. AN UPPER TROUGH FROM IDAHO TO  
ARIZONA TO MOVE EWD TO THE ERN EXTENT OF THE ROCKIES BY THE END OF  
THE DAY. DEEPENING SWLY FLOW BUT ALSO HEIGHT FALLS AHEAD OF THE  
TROUGH TO RESULT IN A DRYLINE THAT WILL BECOME MORE DEFINED THROUGH  
THE DAY THEN MOVE EWD TO AROUND THE CAPROCK ESCARPMENT BY LATE AFTN.  
SELY LOW LEVEL FLOW TO THE EAST OF THE DRYLINE TO BRING SOME  
MOISTURE ADVECTION INTO THE ROLLING PLAINS. 00Z MODEL RUNS CONTINUE  
A CONVECTIVE PRECIP SIGNAL MAINLY ACROSS THE ERN PANHANDLE INTO THE  
NRN ROLLING PLAINS EWD INTO WRN OKLAHOMA AND NW TEXAS...ALTHOUGH  
MAYBE NOT AS ROBUST A SIGNAL AS SEEN PREVIOUSLY. SOME CONCERNS ARE  
QUALITY OF THE LOW LEVEL MOISTURE /MUST GET AS FOR SOUTH AS SAN  
ANTONIO AND COLLEGE STATION BEFORE FINDING A 60F DEW POINT AS OF  
08Z/...POSSIBLE LIMITATIONS DUE TO MID AND HIGH CLOUD COVER ON TEMPS  
AND LAPSE RATES /MARGINAL EFFECT EXPECTED/...AND STRENGTH OF THE  
CAP. AS FOR MOISTURE...SHOULD SEE MID 50S MOVE INTO THE ERN ZONES  
ALTHOUGH REMAINING FAIRLY SHALLOW. STILL THAT TYPE OF MOISTURE IS  
FAR FROM DISCOUNTING PRECIP. BEST PUSH TO THE DRYLINE IS EXPECTED TO  
BE TO THE NORTHEAST TOWARD THE ERN PANHANDLE WITH UPPER SUPPORT ALSO  
FOCUSING ON THAT DIRECTION. THIS AREA MOST LIKELY TO BREAK THE CAP  
WITH AREA FURTHER SOUTH TOWARD THE SRN ROLLING PLAINS POSSIBLY  
STAYING CAPPED UNTIL EARLY EVENING WHEN DEVELOPMENT OF A LOW LEVEL  
JET WOULD INCREASE MOISTURE CONVERGENCE AND ADVECTION POTENTIALLY  
HELPING ERODE THE CAP ENOUGH THERE FOR SOME PRECIP TO BUILD SWD PER  
THE WRF-NAM SOLUTION. ALL THAT TO SAY THAT PREVIOUS POP FCST LOOKS  
PRETTY GOOD. WILL MAKE SOME MINOR ADJUSTMENTS...SHIFTING WRN EDGE OF  
SLIGHT CHANCE TO THE EAST WITH THE DRYLINE AND LOWERING AFTN POPS  
ACROSS THE SRN ROLLING PLAINS WHERE STRONGER CAP EXPECTED.  
 
SEVERE THREAT WILL REMAIN AS MIXED LAYER CAPE OF 1000-2000 J/KG  
EXPECTED WITH BULK SHEAR SUPPORTING SUPERCELLS...PARTICULARLY AS THE  
EVENT GOES ON WITH INCREASING LOW LEVEL JET INCREASING SHEAR. STORMS  
LIKELY TO BE FAIRLY HIGH BASED TO BEGIN WITH WITH LARGE HAIL THE  
MAIN THREAT AND TORNADO POTENTIAL LIMITED BY HIGH LCL AND LOW LEVEL  
WINDS LIKELY BACKED CLOSER TO SOUTH THAN EAST. THE UPPER TROUGH  
MOVING OVER THE PANHANDLE TOWARD 06Z WILL SHIFT CHANCES TO THE EAST  
OF THE FCST AREA.  
 
PREVIOUS TEMP FCST LOOKS FINE WITH MINOR ADJUSTMENT TOWARD 00Z MOS.  
WINDS TO BECOME BREEZY TO WINDY WITH TIGHTENING PRESSURE GRADIENT...  
AGAIN IN LINE WITH PREVIOUS FCST. COLD FRONT LATE TONIGHT BEHIND THE  
TROUGH WILL SEE WINDS COME AROUND FROM THE NORTH.  
 

 
   
LONG TERM
 
 
THE ONLY CHALLENGING WEATHER IN THIS LONG TERM WINDOW FROM THURSDAY  
THRU TUESDAY WILL UNFOLD THE WEEKEND AS A NEGATIVE TILT UPPER  
ENTERS THE PICTURE. BEFORE THEN...SHALLOW RIDGING ALOFT WILL MAKE  
FOR TRANQUIL CONDITIONS WITH A RETURN TO SOME MOIST SOUTHERLY  
WINDS BY FRIDAY BEHIND A SURFACE RIDGE. AS SOON AS FRI NIGHT...A  
DRYLINE COULD ALREADY BE BISECTING THE CWA FROM SW TO NE. GRADUAL  
BACKING OF WINDS ALOFT ON SATURDAY IN ADVANCE OF THE UPPER LOW  
WOULD TEND TO FAVOR THIS DRYLINE NOT MIXING TOO FAR EAST DURING  
THE DAY...SO WE WILL KEEP SLIGHT CHANCE POPS OFF THE CAPROCK  
DURING THE AFTN AND OVERNIGHT.  
 
PRESSURE FALLS STILL TO OUR WEST BY SAT EVNG MAY INDEED PULL THE  
DRYLINE MUCH FARTHER WEST THAN MODELS INDICATE. IT/S NOT UNCOMMON  
TO SEE MODELS SERIOUSLY UNDERESTIMATE THE WWD EXTENT OF  
RETROGRADING DRYLINES IN THESE SETUPS...BUT IT/S STILL TOO SOON TO  
EXPAND PRECIP MENTION ONTO THE CAPROCK FOR THIS POSSIBILITY.  
NONETHELESS...THE STRONGEST HEIGHT FALLS AND A QUICK-MOVING  
PACIFIC FRONT WILL OVERTAKE THE SOUTH PLAINS SAT NIGHT. FOR THOSE  
WHO REMEMBER SATURDAY NIGHT 4/14/2012...SUCH A SCENARIO WAS  
REALIZED MUCH FARTHER WEST THAN MODELS INDICATED WHICH CAUGHT  
MANY FORECASTERS BY SURPRISE. A SIMILAR PATTERN IS IN PLACE THIS  
TIME AROUND...SO WE CAN/T ENTIRELY IGNORE THIS POSSIBILITY.  
 
BY SUNDAY...THE NEGATIVE TILT UPPER LOW IS SHOWN TO DEEPEN WHILE  
HOOKING NEWD ACROSS SERN CO AND SWRN KS. THIS IS UNFORTUNATELY A  
TEXTBOOK PATTERN FOR CLASSIC SOUTH PLAINS DUST EVENTS...SO WESTERLY  
WINDS HAVE BEEN RAMPED UP CONSIDERABLY SUN AFTN ALONG WITH BLOWING  
DUST MENTION. HIGH WINDS MAY SPARE THE REGION AS THE 500MB AND 700MB  
WIND MAXIMA DO NOT APPEAR PARTICULARLY ROBUST ATTM. FIRE WEATHER  
MAY ALSO FAIL TO EMERGE AS MODELS ARE TRENDING MUCH COOLER BEHIND  
THE PACIFIC FRONT...THOUGH WE/VE SEEN THIS BEFORE WHERE DRIER AND  
WARMER WAS THE ACTUAL RESULT. WE DID COOL SUNDAY/S HIGHS A TOUCH...  
BUT ARE STILL RESIDING ABOVE MEX AND ECM MOS. COOL AND DRY NW  
FLOW THEN SETS UP EARLY NEXT WEEK AS THE UPPER LOW SLOWS AND  
FILLS TO OUR NORTHEAST. GULF MOISTURE WILL SADLY BE SWEPT BACK TO  
ITS ORIGIN IN THIS PATTERN...SO MEASURABLE PRECIP WILL ONCE AGAIN  
BECOME A SCARCE COMMODITY.  
 

 
   
FIRE WEATHER
 
 
LOW END RED FLAG WARNING LOOKS REASONABLE WRN TWO COLUMNS OF  
COUNTIES. WINDS WEST OF THE DRYLINE TO INCREASE TOWARD 25 MPH AT THE  
20-FOOT LEVEL WITH RH BOTTOMING OUT AROUND 10 PCT. SOME QUESTION HOW  
LONG THAT COMBINATION WILL LAST ACROSS THIS AREA BUT NEAR 3 HOURS IF  
NOT EXCEEDING THAT DURATION SEEMS REASONABLE. WILL MAINTAIN THE  
INHERITED WARNING AND UPGRADE THE WATCH AREA TO A WARNING.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
FRIONA 85 44 75 44 86 / 10 0 0 0 0  
TULIA 86 46 76 47 87 / 20 10 0 0 0  
PLAINVIEW 87 48 77 49 89 / 20 10 0 0 0  
LEVELLAND 88 47 79 52 90 / 10 0 0 0 0  
LUBBOCK 88 50 79 53 90 / 10 0 0 0 0  
DENVER CITY 88 50 77 53 89 / 10 0 0 0 0  
BROWNFIELD 89 49 79 54 91 / 10 0 0 0 0  
CHILDRESS 89 56 79 49 89 / 50 40 0 0 0  
SPUR 87 53 80 53 92 / 30 20 0 0 0  
ASPERMONT 89 59 80 53 94 / 30 30 0 0 0  
 

 
   
LUB WATCHES/WARNINGS/ADVISORIES
 
 
RED FLAG WARNING FROM 1 PM THIS AFTERNOON TO 9 PM CDT THIS  
EVENING FOR THE FOLLOWING ZONES:  
TXZ021-022-027-028-033-034-039-040.  
 

 
 

 
 
07/93  
 
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