649  
FXUS64 KLUB 290449  
AFDLUB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LUBBOCK TX  
1149 PM CDT FRI APR 28 2017  
   
AVIATION
 
 
FRONT HAS NOW MOVED THROUGH ALL OF THE TAF SITES WITH BREEZY  
NORTHERLY WINDS IN ITS WAKE. LOW CLOUDS (MVFR TO IFR) WILL FILL  
IN BEHIND THE FRONT OVER THE NEXT FEW HOURS AND THEN PERSIST  
THROUGH THE REST OF THE TAF WINDOW. IN ADDITION, SHOWERS AND  
THUNDERSTORMS HAVE INCREASED IN COVERAGE IN THE LAST HOUR AND  
WILL LIKELY PASS NEAR OR AFFECT ALL THREE OF THE TAF SITES OVER  
THE NEXT FEW HOURS. IMPACTS SHOULD BE FAIRLY MINIMAL AT KLBB AND  
KCDS, BUT COULD BE MORE SIGNIFICANT AT KCDS WHERE MORE ROBUST  
MOISTURE IS IN PLACE A COULD FUEL A FEW STRONG TO SEVERE STORMS.  
THE BETTER STORM CHANCES WILL SHIFT EAST OF THE TERMINALS BY  
09-12Z, THOUGH ADDITIONAL SHOWERS (PERHAPS A LITTLE THUNDER) WILL  
BE POSSIBLE BEYOND THAT, PARTICULARLY LATE SATURDAY AFTERNOON INTO  
THE EVENING HOURS. GUSTY NORTHERLY WINDS WILL PERSIST THROUGH THE  
ENTIRE PERIOD.  
 

 
   
PREV DISCUSSION
 
/ISSUED 1044 PM CDT FRI APR 28 2017/  
 
UPDATE...  
PRODUCTS HAVE BEEN UPDATED TO REFLECT THE SEVERE THUNDERSTORM  
WATCH NOW IN EFFECT FOR CHILDRESS AND COTTLE COUNTIES UNTIL 6 AM.  
IT MAY TAKE ANOTHER HOUR OR TWO UNTIL STORMS REALLY GET GOING IN  
THE WATCH BUT THE THREAT FOR ELEVATED HAILERS WILL QUICKLY  
INCREASE AROUND OR AFTER MIDNIGHT. THE FORECAST HAS THIS WELL IN  
HAND AND NO ADDITIONAL UPDATES HAVE BEEN MADE AT THIS TIME.  
 
PREV DISCUSSION... /ISSUED 922 PM CDT FRI APR 28 2017/  
 
UPDATE...  
OUTFLOW AIDED FRONT CONTINUES TO MARCH SOUTHWARD...STRETCHING  
ROUGHLY FROM MEMPHIS TO ABERNATHY TO TOKIO AT 02Z. NORTHERLY WINDS  
GUSTING TO 40 TO 45 MPH ARE ADVECTING IN MUCH COLDER AIR BEHIND  
THE FRONT WITH TEMPERATURES RAPIDLY DROPPING FROM THE 70S INTO THE  
40S AND 50S. THIS FRONT WAS A LITTLE AHEAD OF SCHEDULE AND  
ADJUSTED THE GRIDS TO ACCOUNT FOR THIS. STEADY MOISTENING AND LIFT  
SPREADING IN FROM THE WEST HAS SUPPLIED PLENTY OF CLOUD COVER AND  
EVEN A FEW SPRINKLES AND LIGHT SHOWERS LOCALLY, THOUGH THE BULK  
OF THE ACTIVITY TO THIS POINT HAS REMAINED TO OUR NORTH AND  
WEST...FROM CENTRAL NM INTO THE PANHANDLES AND SOUTHWEST KS.  
SHORT-RANGE HIGH-RESOLUTION NWP DOES SUGGEST AN UPTICK IN SHOWER  
AND THUNDERSTORM ACTIVITY LOCALLY BY LATE EVENING AFTER 04-05Z. AS  
THE LIFT SPREADS OFF THE CAPROCK IT WILL ENCOUNTER IMPROVING  
MOISTURE/INSTABILITY LEVELS AND THIS SHOULD LEAD TO MORE ROBUST  
CONVECTION LATE TONIGHT (AFTER MIDNIGHT). A FEW OF THESE ELEVATED  
STORM COULD BECOME STRONG TO SEVERE WITH THE POTENTIAL OF LARGE  
HAIL. IT APPEARS THE SOUTHEAST TEXAS PANHANDLE INTO THE NORTHERN  
ROLLING PLAINS WILL HAVE THE BEST SHOT OF SEEING AN OVERNIGHT  
SEVERE STORM, AND WE HAVE MAINTAINED THE SEVERE MENTION IN THE  
GRIDS FOR THIS AREA FROM 06-12Z. A FEW STRONGER STORMS MAY EVEN  
TRY TO DEVELOP FURTHER SOUTHWARD OVER THE ROLLING PLAINS BEFORE  
THE BETTER MOISTURE, INSTABILITY AND LIFT QUICKLY SHIFT EAST OF  
THE AREA AROUND OR SHORTLY AFTER DAYBREAK SATURDAY. SATURDAY WILL  
BE COOL/RAW AND BREEZY/WINDY THOUGH THE CHANCES FOR MEASURABLE  
PRECIPITATION WILL LIKELY BE FAIRLY LOW THROUGH MUCH OF THE DAY  
AS DRIER AIR ALOFT SPREADS OVER THE COOL AND MOIST LOW-LEVEL AIR  
IN PLACE. THIS COULD CHANGE BY LATER HALF OF THE AFTERNOON INTO  
SATURDAY EVENING WHEN THE APPROACH OF THE COLD CORE LOW MAY RENEW  
PRECIPITATION CHANCES, PARTICULARLY ACROSS THE NORTHWEST ZONES  
WHERE THE RAIN COULD MIX WITH AND/OR CHANGE OVER TO SNOW FOR A  
PERIOD.  
 
PREV DISCUSSION... /ISSUED 654 PM CDT FRI APR 28 2017/  
 
AVIATION...  
AN OUTFLOW AIDED/ENHANCED FRONT WAS SEEN ON THE AMARILLO WSR-88D  
ADVANCING SOUTHWARD THROUGH THE SOUTHERN TEXAS PANHANDLE. GIVEN  
ITS CURRENT SPEED IT SHOULD MOVE THROUGH KPVW AROUND 0130Z, THEN  
THROUGH KLBB AND KCDS FROM 03-05Z. GUSTY NORTHERLY WINDS AND  
COOLER AIR WILL QUICKLY MOVE IN BEHIND THE FRONT, WITH LOW CLOUDS  
(MVFR TO IFR CIGS) LIKELY DEVELOPING A FEW HOURS (GIVE OR TAKE AN  
HOUR OR TWO) AFTER THE FROPA. THE LOW CLOUDS AND GUSTY NORTHERLY  
WINDS WILL PERSIST THROUGH THE DAY SATURDAY. IN ADDITION TO THE  
CLOUDS AND WINDS, AREAS OF SHOWERS WERE ALREADY AFFECTING MUCH OF  
THE PANHANDLES WHILE TRYING TO DEVELOP INTO THE NORTHERN SOUTH  
PLAINS. ANY OF THE TERMINALS COULD SEE A HIGH-BASED SHOWER  
THROUGH THE EVENING HOURS WITH EVEN SOME THUNDER NOT OUT OF THE  
QUESTION. THE BEST SHOT FOR MORE ROBUST ELEVATED THUNDERSTORMS  
WILL BE AROUND KCDS AROUND/AFTER MIDNIGHT AND A TEMPO GROUP WAS  
INCLUDED TO REFLECT THIS THREAT. SHOWER/STORM CHANCES WILL THEN  
LIKELY BE ON THE LOW SIDE THROUGH MUCH OF SATURDAY MORNING BEFORE  
RENEWING SATURDAY AFTERNOON OR EVENING.  
 
PREV DISCUSSION... /ISSUED 342 PM CDT FRI APR 28 2017/  
 
SHORT TERM...  
COOL NORTHERLY SURFACE FLOW FROM EARLIER TODAY HAS SINCE VEERED S-SE  
IN RESPONSE TO PRESSURE FALLS/THERMAL TROUGHING FOCUSING ACROSS  
EASTERN NM. THIS PROCESS IS SERVING TO DRAW THE BACK EDGE OF GULF  
MOISTURE WESTWARD ACROSS NW TEXAS, AND AFTER SUNSET DEWPOINTS NEAR  
60F SHOULD OCCUPY OUR EASTERN COLUMN OF COUNTIES FROM CONTINUED  
EASTERLY WINDS. FARTHER WEST, AFOREMENTIONED SURFACE TROUGHING WILL  
EDGE EAST AHEAD OF WEAK HEIGHT FALLS PRECEDING A CLOSED UPPER LOW  
NOW NEARING THE FOUR CORNERS. WITH STEADY TOP-DOWN MOISTENING  
ALREADY UNDERWAY FROM CENTRAL NM INTO THE WESTERN TX PANHANDLE, THIS  
PRECIPITATION SHOULD IMPROVE MARKEDLY TONIGHT MAINLY TO OUR NORTH  
WHERE ISENTROPIC ASCENT IS MAXIMIZED BEHIND A COLD FRONT. AS THIS  
FRONT SPILLS SOUTH AFTER SUNSET, A WINDOW FOR SEVERE STORMS SHOULD  
OPEN PRIMARILY NEAR THE HIGHWAY 83 CORRIDOR NEAR THE DEEPER  
MOISTURE. AMPLE ELEVATED CAPE OF 2000-3500 J/KG LOOKS QUITE  
FAVORABLE FOR SEVERE HAIL FROM ANY STORMS THAT REALIZE THIS  
INSTABILITY. GIVEN THIS ENVIRONMENT AND FAIR AGREEMENT AMONG HIGH  
RESOLUTION MODELS, HAVE INSERTED LARGE HAIL IN THE FORECAST FOR  
THESE AREAS AFTER MIDNIGHT. PRECIP CHANCES ELSEWHERE ARE MUCH MORE  
CONDITIONAL AS VAST MOISTURE DEFICITS RULE THE LOWEST 6-10K FEET,  
AND SHALLOW FRONTAL FORCING WILL NOT IMPROVE THIS SITUATION ANY.  
 
BY THE TIME POST-FRONTAL LOW CLOUDS ARRIVE AFTER MIDNIGHT, MID-LEVEL  
SATURATION ALOFT WILL BE DRYING OUT AS DRY SLOTTING EXPANDS OUT OF  
NORTHERN CHIHUAHUA. THIS ILL-TIMED LOW LEVEL MOISTENING LOOKS TO  
KEEP MUCH OF THE REGION DRY SATURDAY MORNING, WITH THE MAIN  
EXCEPTION BEING IN OUR FAR NW ZONES CLOSER TO A WARM CONVEYOR BELT  
OF PRECIP IMMEDIATELY EAST OF THE UPPER LOW. DRY SLOT VIGOR MAY BE  
TOO RESILIENT FOR ADDITIONAL POPS ELSEWHERE ON SATURDAY AFTERNOON  
EVEN AS A STOUT COLD POCKET (-25C AT 500MB) ROTATES EAST WITH THE  
UPPER LOW. OPTED TO SHAVE AFTERNOON POPS BACK TO SLIGHT CHANCE OVER  
ALL BUT OUR NW ZONES AS MODELS ARE SIMPLY TRENDING DRIER. STILL,  
SOME SHALLOW CONVECTIVE RAIN SHOWERS COULD MATERIALIZE ALONG THE  
LEADING EDGE OF THE COLD POCKET, BUT DIURNAL HEATING AND SUBSEQUENT  
DESTABILIZATION WILL BE MINIMAL UNDER WHAT LOOKS TO BE PERSISTENT  
STRATUS AND COLD ADVECTION. GFS SEEMS OVERLY BULLISH IN RETREATING  
THE FRONT ACROSS OUR SW ZONES BY MIDDAY AHEAD OF WARM, GUSTY SW  
WINDS, SO WE CONTINUE TO FAVOR THE COLDER NAM AND SHORT BLENDED  
GUIDANCE. HIGH TEMPS ON SATURDAY WILL LIKELY OCCUR OVERNIGHT AS COLD  
AIR ONLY GAINS MORE GROUND AND DEPTH REGION WIDE THROUGHOUT THE  
DAYTIME ON BRISK NORTHERLY WINDS.  
 
LAST BUT NOT LEAST, PROSPECTS FOR RAIN CHANGING TO SNOW REMAIN IN  
THE OFFING FOR PARMER AND SURROUNDING COUNTIES, ESPECIALLY LATE IN  
THE AFTERNOON. PRESENCE OF THE STOUT COLD POCKET DOES GARNER SOME  
WEAK INSTABILITY PER FORECAST SOUNDINGS AT CLOVIS, BUT MARGINAL  
TEMPS NEAR THE SURFACE SHOULD KEEP ACCUMULATIONS SLIM TO NONE UNTIL  
THE EVENING AS DISCUSSED IN THE LONG TERM SECTION BELOW.  
 
LONG TERM...  
GUIDANCE IS IN RELATIVELY GOOD AGREEMENT WITH REGARD TO THE  
POSITIONING OF THE UPPER LEVEL STORM SYSTEM THAT WILL BRING THIS  
WEEKEND'S COOL SNAP--THAT IS TO SAY, THE LOW SHOULD BE CENTERED  
AROUND KTCC. AS SUNDAY PROGRESSES, THE LOW SHOULD SWING EASTWARD  
INTO WESTERN OKLAHOMA BEFORE LIFTING NORTHWARD INTO KS. THE GFS  
EXHIBITS MORE NORTHWARD MOVEMENT THAN THE SLOWER ECM. NORTHWESTERLY  
FLOW ALOFT WILL PERSIST ON MONDAY BEHIND THE EXITING SYSTEM WITH AN  
EMBEDDED DISTURBANCE (OF A SERIES) DURING THE DAY ON TUESDAY. A  
SHARPER TROUGH COMES WEDNESDAY BEFORE RIDGING SETS UP FOR THE END OF  
THE WORK WEEK.  
 
BREEZY AND CHILLY NORTHERLY WINDS ARE EXPECTED SATURDAY EVENING  
ALONG WITH POST-FRONTAL SHOWER ACTIVITY PARTICULARLY IN THE  
NORTHWEST. THE CORE OF THE LOW LOOKS TO REMAIN JUST NORTH OF THE  
AREA. HOWEVER, THE CORE SHOULD BE JUST CLOSE ENOUGH TO KEEP A RISK  
OF PRECIP MUCH OF THE NIGHT IN OUR TOP ROW THOUGH SOME RISK  
REMAINS FURTHER SOUTH. PRECIP PHASE LOOKS TO BE MAINLY SNOW  
SATURDAY EVENING/OVERNIGHT IN THE NW SOUTH PLAINS AND SE PANHANDLE  
WHERE LIGHT ACCUMULATIONS STILL LOOK FEASIBLE. THE SURFACE FLOW  
REMAINS NORTHWESTERLY UNTIL EARLY MONDAY MORNING BECOMING  
SOUTHWESTERLY FOR A BRIEF SPELL THEN BACK TO WESTERLY. ANOTHER  
MODEST FRONT EEKS IN TUESDAY MORNING FOLLOWED BY A SOMEWHAT  
STRONGER FRONT ON WEDNESDAY WITH A SECONDARY SURGE ON WEDNESDAY  
NIGHT WHICH KEEPS US IN NORTHERLY FLOW TIL FRIDAY.  
 

 
   
LUB WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
23/33/23  
 
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