107 
FXUS64 KLUB 151148
AFDLUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
648 AM CDT SUN SEP 15 2013

.AVIATION...
NO RISK OF FOG OR SUB-VFR CIGS THIS MORNING AS DRIER SOUTHERLY
FLOW PREVAILS. INSTEAD THERE WILL BE PLENTY OF MID AND UPPER LEVEL
CLOUDINESS TODAY INTO TONIGHT. IN ADDITION THERE IS A SLIM CHANCE
OF AN ISOLATED SHOWER OR STORM THIS AFTERNOON...WITH CONVECTIVE
CHANCES INCREASING TONIGHT AS A WEAK FRONT APPROACHES FROM THE
NORTH. EITHER TERMINAL COULD EXPERIENCE A STORM TONIGHT...BUT IT
APPEARS THE BETTER CHANCES WILL BE AT KCDS WHERE A PROB30 GROUP
WAS INCLUDED FOR LATE THIS EVENING INTO EARLY MONDAY MORNING.
OUTSIDE OF ANY THUNDERSTORMS VFR CONDITIONS WILL PREVAIL.

&&

.PREV DISCUSSION... /ISSUED 353 AM CDT SUN SEP 15 2013/ 

SHORT TERM...
THE END OF THE WEEKEND WILL FEATURE ANOTHER WARM MID-SEPTEMBER DAY 
WITH AT LEAST A LOW CHANCE OF SHOWERS/STORMS TODAY INCREASING INTO
TONIGHT. 

THE SOUTH PLAINS WILL REMAIN UNDER SOUTHWESTERLY MID/UPPER FLOW 
TODAY AS THE REGION IS POSITIONED BETWEEN A FLAT RIDGE SPANNING MUCH 
OF TEXAS THROUGH THE DEEP SOUTH AND A SLOWLY EVOLVING COMPLEX 
WESTERN TROUGH. IN ADDITION...A POTENT SHORTWAVE TROUGH WILL DIVE 
THROUGH THE GREAT LAKES TODAY HELPING TO DRIVE A FRONT SOUTHWARD 
THROUGH THE CENTRAL PLAINS. EARLY MORNING WATER VAPOR IMAGERY DOES 
SHOW A POCKET OF DRIER AIR GETTING CAUGHT UP BETWEEN THE SOUTHEAST 
RIDGE AND WESTERN TROUGH...AND THIS MODEST DRYING AND THINNING 
MONSOON PLUME WILL SPREAD OVER NORTHWEST TEXAS TODAY...THOUGH 
SHALLOWER MOISTURE IS ALSO PROGGED TO MOVE AROUND THE SOUTHWEST 
PERIPHERY OF THE RIDGE AND INTO THE FA FROM THE SOUTHEAST THIS 
AFTERNOON. STRONG HEATING AND THE SUBTLE MOISTENING MAY BE ENOUGH 
TO POP AN ISOLATED SHOWER OR STORM...THOUGH COVERAGE AND DURATION OF 
THIS ACTIVITY SHOULD BE MINIMAL. STILL...HAVE DECIDED TO CARRY AN 
ISOLATED THUNDER MENTION WITH 10 PERCENT POPS FOR THIS POSSIBILITY 
ACROSS MUCH OF THE AREA. TURNING TO THE NORTHWEST...A PREFRONTAL 
TROUGH MAY FLIRT WITH THE SOUTHWEST PANHANDLE THIS AFTERNOON WELL IN 
ADVANCE OF THE FRONT /LIKELY IN OR NEAR THE OKLAHOMA PANHANDLE 
AROUND 00Z/ AND THIS TROUGH COULD PROVIDE ENOUGH OF A FOCUS FOR 
ISOLATED HIGH-BASED LATE DAY CONVECTION THERE. REGARDLESS IT WILL BE 
A WARM DAY WITH HIGHS AROUND 5 DEGREES ABOVE AVERAGE.

BETTER STORM CHANCES SHOULD DEVELOP THIS EVENING INTO TONIGHT AS A 
PORTION OF THE WESTERN TROUGH LIFTS OVER THE HIGH PLAINS AND WEAK 
LARGE SCALE ASCENT GRAZES THE REGION. THE STRONGEST FORCING WILL BE 
TO OUR NORTH...BUT MAY BE CLOSE ENOUGH TO INSPIRE EXPANDING 
CONVECTION...LIKELY FAVORING THE NORTHERN AND NORTHWEST ZONES...WITH 
LOWER CHANCES FARTHER TO THE SOUTH AND EAST. A CONVECTIVELY AIDED 
FRONTAL BOUNDARY MAY EVEN MAKE A PUSH TOWARD THE NORTHERN 
ZONES...POTENTIALLY ENHANCING/MAINTAINING STORMS CHANCES THROUGH THE 
NIGHT...THOUGH THE EXACT POSITION OF THE FRONT IS HIGHLY UNCERTAIN. 
HENCE...HAVE 30-40 PERCENT POPS ACROSS THE SOUTHERN TEXAS PANHANDLE 
TAPERING TO AROUND 15 PERCENT ACROSS THE SOUTHERN ZONES TONIGHT. 
RELATIVELY SLOW STORM MOTION...TRAINING CELLS AND ABOVE NORMAL PWATS 
COULD SUPPORT LOCALLY HEAVY RAIN...PARTICULARLY IF A LOW-LEVEL FOCUS 
/BOUNDARY/ CAN MAKE IT INTO THE AREA. LOWS TONIGHT WILL BE ON THE 
WARM SIDE OF AVERAGE FOR MOST SPOTS GIVEN THE RELATIVELY MOIST 
ATMOSPHERE AND CONSIDERABLE CLOUDINESS.

LONG TERM...
WE ARE STILL EXPECTING RAIN CHANCES TO INCREASE ACROSS THE BOARD
MONDAY AS WE SHOULD HAVE A DIFFUSE FRONTAL ZONE IN THE AREA...WEAK
TROUGHING ALOFT...AND AN INCREASE IN DEEP LAYER MOISTURE.
HOWEVER...DYNAMICS OVERALL WILL REMAIN WEAK...AND THERE IS STILL
SOME QUESTION REGARDING HOW MUCH TROPICAL MOISTURE WE CAN TAP INTO
AS PROGS IN GENERAL SHOW A WEAK SRLY COMPONENT TO THE MID-LVL
FLOW...SUGGESTING MUCH OF THE THIS MOISTURE SOURCE MAY REMAIN
WELL TO OUR SOUTH. THE ECMWF CONTINUES TO BE THE MOST AGGRESSIVE
WITH DEVELOPING THE MOISTURE CHANNEL OVER OUR AREA THROUGH
TUESDAY...WITH THE GFS AND NAM DRIER. WITH THIS IN MIND...IT SEEMS
PRUDENT TO KEEP OUR POPS IN THE 30 TO 40 PERCENT RANGE FOR THE
MOST PART...AND DOWNPLAY THE OVERALL HEAVY RAIN THREAT FOR NOW.
FCST PWATS ARE AROUND 1.2 TO 1.4 INCHES AND WILL COMBINE WITH SLOW
STORM MOTION TO GIVE AT LEAST A THREAT OF SOME LOCALLY HEAVY
DOWNPOURS. THE FRONT SHOULD WASH OUT BY TUESDAY BUT WE SHOULD
RETAIN SOME WEAK MID-LVL CYCLONIC CURVATURE AND SUFFICIENT DEEP
MOISTURE TO SUPPORT OUR CHANCE POPS IN PLACE THROUGH THE EVENING.

BY WED...WHATEVER MOISTURE PLUME WE HAD WILL WANE AND SHIFT EAST
AND WE SHOULD DRY OUT TEMPORARILY. BUT ALREADY ON THURSDAY...A
SHARP SHORTWAVE SWINGING THROUGH THE NRN PLAINS WILL DRIVE A COLD
FRONT SOUTHWARD. THIS FRONT COULD ARRIVE IN OUR NRN COUNTIES AS EARLY
AS THURS EVENING. MEANWHILE...THE UPPER RIDGING OVER THE NRN GULF
COAST STATES WILL WEAKEN AND SHIFT SE...ALLOWING HIGHER MOISTURE
LEVELS TO RETURN TO WEST TEXAS. WHILE THE GFS AND ECMWF DIFFER IN
MANY OF THE DETAILS...THEY BOTH SHOW RATHER STRONG QPF SIGNALS
LATE THU INTO FRI. AS SUCH WE/VE CONTINUED THE TREND OF INCREASING
CLOUD COVER AND POPS IN THIS TIME FRAME AS WELL AS LOWERING TEMPS
FOR FRIDAY. SO EVEN IF THE TROPICAL MOISTURE PLUME DOESN/T REALLY PAN
OUT MON-TUE IT LOOKS LIKE WE/LL GET ANOTHER CHANCE LATE IN THE
WEEK. BY NEXT WEEKEND...ANOTHER TROUGH WILL BE MOVING ACROSS THE
WRN STATES AND COULD BRING US ANOTHER CHANCE OF PRECIP SUN INTO
EARLY NEXT WEEK.

MOS TEMPS ARE VERY FLAT ALL NEXT WEEK - WITH HIGHS MAINLY IN THE
80S. IT LOOKS LIKE WED COULD BE THE WARMEST DAY OF THE
PERIOD...AND THEN TEMPS THU INTO FRI WILL DEPEND ON THE TIMING AND
STRENGTH OF THE FRONT AND THE COVERAGE OF TSTM ACTIVITY IN IT/S
WAKE.

&&

.PRELIMINARY POINT TEMPS/POPS...
FRIONA        85  60  80  59  81 /  10  40  40  30  40 
TULIA         86  62  83  63  84 /  10  40  40  30  40 
PLAINVIEW     87  63  84  62  83 /  10  30  40  30  30 
LEVELLAND     88  62  84  61  82 /  10  20  40  20  30 
LUBBOCK       89  66  86  65  84 /  10  20  30  20  30 
DENVER CITY   87  62  84  62  82 /  10  20  30  20  30 
BROWNFIELD    88  64  85  63  83 /  10  20  30  20  30 
CHILDRESS     93  69  89  68  88 /  10  30  30  20  30 
SPUR          91  66  89  65  86 /  10  20  30  20  30 
ASPERMONT     95  68  90  69  89 /  10  10  30  20  30 

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

23/33/23