620  
FXUS64 KLUB 182336  
AFDLUB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LUBBOCK TX  
636 PM CDT MON MAR 18 2019  
   
AVIATION
 
 
VFR WILL PREVAIL THE NEXT 24 HOURS, THOUGH CLOUDS WILL BEGIN TO  
THICKEN TUESDAY AFTERNOON AHEAD OF A WEAK COLD FRONT. THE FROPA  
WILL LIKELY OCCUR AROUND OR JUST AFTER THE END OF THE FORECAST  
WINDOW AT THE NORTHERN TERMINALS. BEFORE THEN, SOUTHERLY TO  
SOUTHWESTERLY WINDS WILL BECOME A LITTLE BREEZY ON TUESDAY.  
 

 
   
PREV DISCUSSION
 
/ISSUED 216 PM CDT MON MAR 18 2019/  
 
DISCUSSION...  
UNUSUAL FOR EARLY SPRING IN WEST TEXAS, ANEMIC WINDS WERE THE  
STORY NOT JUST AT THE SURFACE BUT ALL THROUGHOUT THE TROPOSPHERE.  
THIS WAS DUE TO A WEAK UPPER LOW CRAWLING EAST ACROSS FAR WEST  
TEXAS THIS AFTERNOON IN BETWEEN TWO BRANCHES OF THE POLAR JET TO  
ITS NORTH AND SOUTH. BESIDES A SMATTERING OF HIGH CLOUDS AND SOME  
BOUNDARY LAYER CUMULUS PRECEDING THIS DECAYING LOW, NO IMPACTS ARE  
EXPECTED THROUGH TONIGHT AS THIS LOW CONTINUES TO WEAKEN BEFORE  
EVENTUALLY SHEARING APART TOMORROW MORNING OVER THE HILL COUNTRY.  
SOME OF THIS SHEARING WILL BE AIDED BY A TROUGH CARVING SOUTHWARD  
WITHIN THE STRONGER BRANCH OF THE POLAR JET. THIS DEEPER TROUGH  
STILL APPEARS CAPABLE OF SUPPORTING A FEW VERY LIGHT RAIN SHOWERS  
TOMORROW AFTERNOON, GENERALLY IN OUR SOUTHWEST PANHANDLE COUNTIES  
NEAR A COLD FRONT. RAIN CHANCES BY TUE NIGHT LOOK TO FOCUS MORE  
ALONG THE TRAILING FN LAYER ALOFT WHICH IS PROGGED TO TRANSLATE  
VERY LITTLE NORTH OR SOUTH FROM OUR PANHANDLE COUNTIES ALL NIGHT  
LONG. BACKGROUND ASCENT TOMORROW NIGHT CERTAINLY LOOKS MORE  
FAVORABLE COMPARED TO THE AFTERNOON GIVEN IMPROVING PVA AHEAD OF  
THE UPPER TROUGH AXIS AND DECENT UPPER DIVERGENCE AT TIMES.  
 
FOLLOWING TUESDAY NIGHT'S TROUGH AND COLD FRONT, COOL SURFACE  
RIDGING ENSUES ON WEDNESDAY UNDERNEATH A PROGRESSIVE LONGWAVE  
RIDGE. MODELS ARE IN GOOD AGREEMENT THAT THIS RIDGE WILL LOITER A  
BIT LONGER THROUGH THURSDAY AND SERVE TO KEEP MOST/ALL OF THE  
REGION DRY BEFORE AN INFLUX OF SUBTROPICAL MOISTURE ARRIVES THU  
NIGHT AND ESPECIALLY FRI AHEAD OF A SLOW MOVING CLOSED LOW THROUGH  
THE FOUR CORNERS. MEANWHILE, LOW LEVEL MOISTURE RECOVERY LOOKS TO  
MAKE GREAT STRIDES THANKS TO DEEP MERIDIONAL FLOW ADVECTING GULF  
MOISTURE NORTHWARD. THIS PROCESS SHOULD ESTABLISH AN AXIS OF PWATS  
0.75" OR GREATER BY FRIDAY OVER MOST OF THE REGION COLLOCATED  
WITH DECENT MID-LEVEL LAPSE RATES AROUND 8*C/KM WHICH WOULD EASILY  
BE SUPPORTIVE OF THUNDER. HOWEVER, MLCAPE AS A WHOLE APPEARS  
SUBDUED FOR MOST OF THE DAY ON FRIDAY UNDERNEATH THICK CLOUDS AND  
MARGINAL INSOLATION, SO THE SEVERE THREAT COULD BE TEMPERED IN  
FAVOR OF OCCASIONAL HEAVY RAIN GIVEN SUCH DEEP SOUTHERLY FLOW FROM  
THE SURFACE TO 300 MB AND POTENTIAL FOR TRAINING CELLS. SUPERBLEND'S  
BULLISH POPS WERE KEPT LARGELY ON TRACK GIVEN THE FAVORABLE PATTERN  
AND LONG RESIDENCE TIME OF MOISTURE AND ASCENT, BUT THE GREATEST  
WINDOW FOR PRECIP APPEARS TO OPEN FRIDAY NIGHT AS THE UPPER  
CYCLONE ATTAINS A NEGATIVE TILT AND SPREADS THE RRQ OF AN UPPER  
JET ACROSS THE REGION IN CONCERT WITH AMPLE HEIGHT FALLS AND A  
PACIFIC FRONT. WHILE THE DETAILS CONCERNING THE EVOLUTION OF THIS  
STORM SYSTEM ARE SIMILAR BETWEEN THE MODELS, THE ECMWF AND TO A  
LESSER EXTENT THE CMC HAVE TRENDED MUCH FASTER AND DEEPER WITH THE  
LOW THAN THE GFS BY EARLY SATURDAY. WE DID MODIFY RAIN CHANCES ON  
SATURDAY TOWARD THIS FASTER THEME AS MORE OF THE GEFS MEMBERS  
ALSO SUPPORT THIS THINKING OF PRECIP SHIFTING OFF THE CAPROCK BY  
DAYBREAK.  
 
A LIGHTLY UNSETTLED NORTHWEST FLOW REGIME LOOKS TO ENSUE BY THE  
END OF THE WEEKEND INTO EARLY NEXT WEEK AS A SERIES MINOR TROUGHS  
CREST A DEVELOPING RIDGE ACROSS THE INTERMOUNTAIN WEST, BUT THE  
TIMING OF THESE WAVES IS TOO MUCH OF AN UNKNOWN THAT WE'LL REFRAIN  
FROM ENTERTAINING ANY ADDITIONAL POPS PARTICULARLY SINCE PWATS  
WILL BE DEPLETED TO 1/4" OR LOWER FOLLOWING FRIDAY NIGHT'S TROUGH.  
TEMPS IN GENERAL LOOK TO REMAIN NEAR OR A BIT BELOW SEASONAL  
NORMS WITH FORTUNATELY NO THREAT OF STRONG WINDS ANYTIME SOON.  
 

 
   
LUB WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
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