Area Forecast Discussion
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FXUS64 KLUB 030432
AFDLUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
1132 PM CDT TUE SEP 2 2014

.AVIATION...
CONFIDENCE IS A BIT LOWER THAT AN IFR OR MVFR CLOUD DECK WILL
DEVELOP NEAR OR SOUTHWEST OF KLBB EARLY WEDNESDAY...AND ADVECT
OVER THE AIRPORT. LATEST WRF/NAM HAS DRIED THE H850 MB A BIT WHILE
THE RAP H850 MB LAYER IS SLIGHTLY MORE MOIST THAN PREVIOUS RUNS.
ALTHOUGH WE WILL BACK OFF SLIGHTLY ON THE CLOUD LAYER POTENTIAL...
WE WILL RETAIN SOME CHANCE OF A DECK IMPACTING KLBB JUST AFTER
DAYBREAK WEDNESDAY. OTHERWISE...UPPER LEVEL HIGH PRESSURE WILL
DOMINATE THROUGH WEDNESDAY WITH WEAKER FLOW THAN TUESDAY AND
LESSER THUNDER CHANCES. A LOW LEVEL JET TONIGHT SHOULD REMAIN JUST
TO THE NORTH OF THE AREA. RMCQUEEN

&&

.PREV DISCUSSION... /ISSUED 706 PM CDT TUE SEP 2 2014/

AVIATION...
ISOLATED THUNDERSTORMS APPEAR TO HAVE BY-PASSED KLBB WHILE
REMAINING FAR WEST OF KCDS THIS EVENING. VFR EXPECTED TO DOMINATE
OTHER THAN A RISK FOR AN IFR/MVFR CLOUD LAYER TO DEVELOP JUST
AFTER DAYBREAK WEDNESDAY AT KLBB. RMCQUEEN

PREV DISCUSSION... /ISSUED 531 PM CDT TUE SEP 2 2014/

UPDATE...
THUNDERSTORMS HAVE DEVELOPED OVER THE WESTERN AND CENTRAL SOUTH
PLAINS...A BIT SOUTH OF PREVIOUS BEST-GUESS...BUT GIVE SHORT TERM
SOLUTIONS SOME CREDIT. WE HAVE UPDATED FOR LOW COVERAGE THUNDER
THROUGH EARLY THIS EVENING. 1500-2000 JOULES PER KILOGRAM OF
CONVECTIVE ENERGY BUT VERY LITTLE SHEAR CONTRIBUTING TO BRIEF
HEAVY SHOWERS AND BRIEF MOSTLY WEAK HAIL INDICATIONS AT THIS TIME.
ACTIVITY SHOULD TAKE ON BETTER NORTHERLY DRIFT...THOUGH BELIEVE
MOST ACTIVITY WILL RELENT BY DARK. RMCQUEEN

PREV DISCUSSION... /ISSUED 306 PM CDT TUE SEP 2 2014/

SHORT TERM...
FOCUS IN THE SHORT TERM IS ON SMALL CHANCE FOR ISOLATED SHOWERS
AND/OR THUNDERSTORMS LATE THIS AFTN AND THIS EVENING. RADAR IS QUIET
ATTM BUT SATELLITE SHOWING AN AREA OF CUMULUS DEVELOPMENT TO THE
EAST AND SOUTHEAST OF LUBBOCK IN AN AREA WHERE OBJECTIVE ANALYSIS
SHOWS ENHANCED INSTABILITY AND WEAKENING INHIBITION. SOME VERY
MODEST LOW LEVEL SPEED CONVERGENCE AND MOISTURE ADVECTION IN THIS
AREA MAY NOT HELP TOO MUCH BUT CERTAINLY WILL NOT HURT. A WEAK
FRONTAL BOUNDARY PULLED UP STATIONARY NEAR A MORTON TO TULIA LINE
WITH WEAK CONFLUENCE IN ITS VICINITY BUT WITH SFC DEW POINTS ABOUT 5
DEGREES LOWER THAN IN THE FORMER AREA. WOULD EXPECT THESE TWO AREAS
HAVE THE BEST CHANCE OF SEEING CONVECTIVE DEVELOPMENT. 12Z WRF-NAM
HIGHLIGHTS THE LATTER WHILE RECENT RUNS OF THE HRRR FEATURES THE
FORMER. EITHER WAY WILL LIKELY BE DIFFICULT TO GENERATE ANYTHING
OTHER THAN SMALL-SCALE AND ISOLATED SHOWERS WITH AREAL COVERAGE NOT
WARRANTING MENTION IN THE ZONE FCST ATTM.

WEDNESDAY SHOULD BE EVEN MORE DIFFICULT TO PRODUCE PRECIP WITH
STRENGTHENING HIGH PRESSURE OVERHEAD AND LOW LEVEL FLOW BECOMING
MORE UNIFORM FROM THE SOUTH. TEMPS TO REMAIN WARMER THAN NORMAL WITH
BOTH LOWS AND HIGHS NEAR WARMER MAV GUIDANCE LOOKING MORE LIKELY
ATTM.

LONG TERM...
ONLY MINOR CHANGES TO THE LONG TERM FORECAST FOR THIS ITERATION...AS
A MUTED COOLING TREND WILL BE FOLLOWED BY A POTENTIALLY WET WEEKEND
FOR PARTS OF THE REGION.

BY WEDNESDAY EVENING...A MOSTLY ZONAL UPPER FLOW REGIME WILL BE IN
PLACE ACROSS THE CONUS...WITH AN ELONGATED UPPER RIDGE IN PLACE
ACROSS MOST OF THE SOUTH...INCLUDING WEST TEXAS.  WHILE THIS WILL
CONTINUE TO ENSURE MOSTLY DRY CONDITIONS THROUGH THE END OF THE WORK
WEEK...GRADUALLY DROPPING 1000-500 MB THICKNESSES WILL ALLOW
TEMPERATURES TO INCREMENTALLY FALL BACK TO A MORE REASONABLE UPPER
80S ON THE SOUTH PLAINS TO MID 90S ON THE ROLLING PLAINS.

BY LATE IN THE WEEK AND THROUGH THE WEEKEND...A BROAD UPPER TROUGH
WILL PUSH EASTWARD ACROSS THE NORTHERN CONUS...SENDING A
MODEST COLD FRONT SOUTHWARD THROUGH THE CENTRAL PLAINS AND AT LEAST
THE TEXAS PANHANDLE.  MEANWHILE DEEPER MONSOONAL MOISTURE...POSSIBLY
WITH A CONNECTION TO REMNANTS OF TROPICAL STORM DOLLY...WILL BE
DRAWN NORTHWARD INTO THE SOUTHWEST AND EVENTUALLY EASTWARD AS IT
GETS CAUGHT IN THE WESTERLY UPPER FLOW ASSOCIATED WITH THE
PREVIOUSLY MENTIONED TROUGH.  ALL OF THIS IS EXPECTED TO RESULT IN
INCREASING RAIN CHANCES BEGINNING AS EARLY AS LATE FRIDAY...AND
POSSIBLY LASTING THROUGH LATE SUNDAY DEPENDING ON A FEW FACTORS.
THE MOST PROMINENT OF THESE FACTORS SEEMS TO BE THE TIMING AND
STRENGTH OF THE APPROACHING COLD FRONT...AS THE GFS AND ECMWF REMAIN
ABOUT 24 HOURS APART IN THIS REGARD.  THE GFS INDICATES A
SLOWER...WEAKER FRONT REACHING THE NORTHERN BORDER OF THE CWA LATE
SATURDAY AFTERNOON AND WASHING OUT ACROSS THE CWA SUNDAY.
MEANWHILE...THE ECMWF SOLUTION BRINGS THIS FRONT INTO THE AREA AS
EARLY AS LATE FRIDAY...AND PUSHES THE BOUNDARY WELL THROUGH THE CWA
BY LATE SATURDAY.  THE LATTER SOLUTION NOT SURPRISINGLY DEVELOPS THE
HEAVIEST PRECIPITATION DURING THE LATE FRIDAY THROUGH SATURDAY
TIME FRAME...WHILE THE GFS SEEMS TO BE FOCUSING ON THE LATE SATURDAY
THROUGH LATE SUNDAY TIME FRAME.  GIVEN THAT THE BOUNDARY WILL BE WELL
REMOVED FROM ITS PARENT TROUGH BY THE TIME IT REACHES THIS
LATITUDE...WE WILL CONTINUE TO SIDE WITH THE SLOWER GFS SOLUTION AND
HIGHLIGHT LATE SATURDAY WITH THE HIGHEST POPS.  LIKEWISE...LOW END POPS
WERE ALSO EXTENDED THROUGH SUNDAY EVENING GIVEN THAT IN THIS SLOWER
SCENARIO REMNANTS OF THIS BOUNDARY AND AMPLE MOISTURE WOULD LIKELY
LINGER THROUGH THIS PERIOD.  HOWEVER...UNCERTAINTIES REGARDING
FRONTAL TIMING AND STRENGTH ARE COMPOUNDED FURTHER ON SUNDAY WITH
THE POSSIBILITY OF LINGERING NOCTURNAL CONVECTION AND STABILIZING
OUTFLOWS.

BY MONDAY...THE UPPER RIDGE IS EXPECTED TO SLIGHTLY AMPLIFY ACROSS
THE SOUTHERN PLAINS WHILE THE COLUMN DRIES CONSIDERABLY.  THIS
SHOULD TAPER OFF PRECIPITATION CHANCES UNTIL LATER IN THE WEEK WHEN
ANOTHER POSSIBLY STRONGER COLD FRONT MOVES THROUGH THE REGION.

&&

.PRELIMINARY POINT TEMPS/POPS...
FRIONA        61  92  62  90  62 /  10   0  10  10  10
TULIA         68  93  66  91  66 /  20   0  10   0  10
PLAINVIEW     68  93  66  90  66 /  20   0   0   0  10
LEVELLAND     66  92  66  90  67 /  20   0  10  10   0
LUBBOCK       72  93  68  92  67 /  20   0   0  10   0
DENVER CITY   66  91  66  89  66 /  20   0  10  10  10
BROWNFIELD    68  93  67  90  67 /  20   0   0  10   0
CHILDRESS     75  97  75  96  72 /  10   0   0   0   0
SPUR          73  97  72  94  71 /  10   0   0  10  10
ASPERMONT     76  99  74  96  73 /   0   0   0  10  10

&&

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

$$

99/99/05





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