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000
FXUS64 KLUB 040552
AFDLUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
1152 PM CST TUE DEC 3 2013

.AVIATION...
VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD. A COLD
FRONT MOVING SOUTH OUT OF THE PANHANDLES WILL BRING A NORTHERLY
WIND SHIFT TO KCDS THIS MORNING...WHILE SW WINDS WILL BECOME
BREEZY AT KLBB..SUSTAINED AROUND 15 TO 20 KTS. WINDS WILL DIMINISH
THIS EVENING WHILE A STRONGER FROPA APPROACHES TOWARD THE END OF
THE FORECAST. CLOUD COVER SHOULD BE CONFINED TO HEIGHTS AOA 20K FT
THROUGH 06 UTC...ALTHOUGH LOW STRATUS MAY BE APPROACHING KCDS BY
THAT TIME.

&&

.PREV DISCUSSION... /ISSUED 955 PM CST TUE DEC 3 2013/

UPDATE...
THE COLD FRONT AT 930 PM HAD ALMOST CLEARED SE COLORADO AND WRN
KANSAS AS IT RACES TOWARD THE PANHANDLES. THIS APPEARS TO BE
A FEW HOURS FASTER THAN MODEL PROJECTIONS. THE RAP NOW HAS THE
LEADING EDGE OF THE FRONT INTO THE CHILDRESS AREA BY 11 UTC/5
AM...ABOUT 3 HOURS EARLIER THAN PREVIOUS INDICATIONS. WITH THIS IN
MIND...THE FRONT MAY MAKE BETTER PROGRESS THROUGH THE CWFA BEFORE
STALLING OUT LATE MORNING OR MIDDAY WED. IN FACT...IT IS NOT OUT OF
THE QUESTION THE WIND SHIFT COULD MAKE IT INTO THE CENTRAL SOUTH
PLAINS...ALTHOUGH ALL AVAILABLE GUIDANCE STILL SHOWS SW BREEZES
OUT-DUELING THE FRONT AND LEADING TO A WARM AFTERNOON FOR MOST OF
THE CAPROCK. THEN THE FRONT WILL BLAST THROUGH THE ENTIRE CFWA
WEDNESDAY NIGHT.

THE 00 UTC NAM AND LATEST TTU-WRF AND SREF ALL SUGGEST THAT A
SHORTWAVE APPROACHING FROM THE SW WILL ENHANCE LIFT OVER THE COLD
AIR EARLY THURS MORNING. HOWEVER...AS PREVIOUS DISCUSSION
MENTIONED...MUCH OF THE INITIAL LIFT WILL GO TO SATURATING THE
INITIALLY DRY LOWER-LEVELS AND IT IS UNCERTAIN HOW MUCH PRECIP CAN
ACTUALLY GET WRUNG OUT BEFORE THE FIRST WAVE EXITS MIDDAY. MOST MODEL
PROGS SUGGEST THE BEST PRECIP POTENTIAL WILL BE ACROSS SRN AREAS
WITH THIS FIRST BATCH OF LIFT...WITH SOUNDINGS SHOWING A WINTRY MIX
OF SLEET AND SNOW FOR THE HIGHER ELEVATIONS AND SOME FREEZING RAIN
POTENTIAL OFF THE CAPROCK. THE BETTER CHANCES OF MORE SIGNIFICANT
FROZEN ACCUMULATIONS ARE STILL EXPECTED TO DEVELOP WITH THE
ARRIVAL OF THE MAIN UPPER WAVE THURS EVENING.

A WINTER STORM WATCH CONTINUES FOR THE ENTIRE CFWA BEGINNING 6 AM THURSDAY.

PREV DISCUSSION... /ISSUED 540 PM CST TUE DEC 3 2013/

AVIATION...
VFR CONDITIONS WILL CONTINUE FOR THE NEXT 24 HOURS. A COLD FRONT
WITH A NORTHERLY WIND SHIFT IS EXPECTED TO ARRIVE AT KCDS AROUND
14 UTC. GUSTY WEST WINDS ARE EXPECTED AT KLBB DURING THE DAY...SUSTAINED
AT NEARLY 20 KTS....BEFORE SUBSIDING IN THE EVENING. CONSIDERABLE
UPPER-LEVEL CLOUDINESS WILL ALSO CONTINUE TO STREAM OVER THE AREA.

PREV DISCUSSION... /ISSUED 303 PM CST TUE DEC 3 2013/

SHORT TERM...
WEATHER PATTERN IS DOMINATED BY A HIGH AMPLITUDE RIDGE OFF THE WEST
COAST AND A STRONG LOW OVER MANITOBA...A SET-UP CONDUCIVE FOR
SHARPLY COLDER WEATHER...BUT MORE ON THAT IN THE LONG TERM.  LEAD
WAVE IN A SERIES OF EMBEDDED DISTURBANCES ROTATING ABOUT
AFOREMENTIONED LOW WILL APPROACH WEDNESDAY EVENING AND WILL HELP
DRIVE INITIAL WIND SHIFT OF THE COLD-SPELL-TO-BE INTO OUR
NORTHEASTERN ZONES.

BREEZY CONDITIONS HAVE PERSISTED TODAY...PARTICULARLY ACROSS THE
NORTHERN ZONES ALONE WITH QUITE DRY LOW LEVELS LEADING TO ELEVATED
FIRE WEATHER CONDITIONS.  ERC VALUES REMAIN ANEMIC ESPECIALLY WITH
THE EXTRA GROUND MOISTURE FROM THE LAST SNOW/ICE EVENT.  INTO
WEDNESDAY...RH VALUES WILL BE ON THE RISE.  FROM A SENSIBLE WEATHER
PERSPECTIVE...PLEASANTLY WARM CONDITIONS WILL PERSIST INTO WEDNESDAY
ALONG WITH INCREASING HIGH CLOUDINESS. THE WINDIEST
CONDITIONS...APPROACHING 20 KTS...SHOULD BE ACROSS THE SOUTHWESTERN
ZONES WELL DISPLACED FROM THE FRONTAL CONVERGENCE ZONE.

LONG TERM...
CERTAINTY IN THE FORECAST HAS INCREASED A BIT FROM THE PREVIOUS
SHIFT ALTHOUGH SOME SIGNIFICANT DIFFERENCES STILL REMAIN TO BE
NEGOTIATED AS THE EVENT DRAWS NEARER. MOIST ISENTROPIC LIFT WILL
BEGIN THURSDAY MORNING AND INCREASE THROUGH THE DAYTIME. GREATEST
LIFT WILL BE ACROSS NEW MEXICO INTO THE WESTERN PANHANDLE WHERE
THERE WILL BE AROUND 30KT OF FLOW ON THE ISENTROPIC SURFACES.
EARLY ON THURSDAY...MID AND UPPER LEVELS WILL BE MOIST AS A WEAK
SHORT WAVE MOVES OVER THE AREA OUT AHEAD OF THE MAIN TROUGH. DRY
AIR IN THE LOWER LEVELS OF THE ATMOSPHERE WILL HAVE TO BE OVERCOME
FOR SIGNIFICANT ACCUMULATIONS TO OCCUR. HOWEVER...BY THE TIME THE
ATMOSPHERE COMPLETELY SATURATES...DEEP LIFT WILL HAVE BEEN ERODED
WITH ONLY ISENTROPIC LIFT REMAINING. BY THE EVENING AS THE MAIN
TROUGH MOVES OUT OVER THE AREA...Q-VECTOR CONVERGENCE WILL BE
MAXIMIZED WITH A STRONG UPPER LEVEL JET. BY DAYBREAK ON
FRIDAY...ISENTROPIC DOWNGLIDE WILL BE RAPIDLY SWEEPING INTO THE
AREA BEHIND THE TROUGH SHUTTING DOWN PRECIPITATION.
ALTHOUGH...FRIDAY WILL LIKELY REMAIN CLOUDY WITH LOW LEVEL
MOISTURE GOING NO WHERE.

A WARM LAYER ALOFT WILL BE MOST PREVALENT NEAR THE SOUTHERN HALF
OF THE FA ADDING ANOTHER LAYER OF DIFFICULTY TO THE FORECAST. VERY
DRY SURFACE AIR MAY PREVENT MUCH PRECIPITATION OVER THE
SOUTHEASTERN TEXAS PANHANDLE EARLY IN THE EVENT ON THURSDAY. ON
THURSDAY...GENERALLY SNOW WILL BE THE PREFERRED PRECIPITATION TYPE
OVER THE SOUTHERN TEXAS PANHANDLE WITH LIGHT FREEZING PRECIPITATION
AND SLEET OVER THE SOUTH PLAINS AND ROLLING PLAINS. GIVEN THE FACT
THAT LIFT WILL ONLY BE COMING FROM ISENTROPIC LIFT...FREEZING
PRECIPITATION ACCUMULATIONS WILL LIKELY BE LIGHT. AS DEEPER LIFT
INCREASES ON THURSDAY NIGHT...THE COLUMN WILL COOL BELOW 0C FOR
MUCH OF THE AREA WITH THE EXCEPTION OF THE SOUTHERN ROLLING
PLAINS. HOWEVER...MID AND UPPER LEVEL DRY AIR WILL BE QUICKLY
WORKING INTO THE REGION FROM THE NORTHWEST ON THURSDAY EVENING. A
MOSTLY SNOW EVENT FOR THE NORTHERN AREAS DURING THURSDAY EVENING
THROUGH FRIDAY MORNING MAY TURN MORE INTO A WINTRY MIX. FREEZING
PRECIPITATION IS STILL THE LIKELY PRECIPITATION TYPE OVER THE
SOUTHERN ROLLING PLAINS. IN ADDITION TO THE WINTRY
PRECIPITATION...TEMPERATURES WILL BE VERY COLD WITH A STRONG
SURFACE RIDGE MOVING INTO THE CENTRAL US ALONG WITH STRONG
MERIDIONAL FLOW TAPING INTO ARCTIC AIR.

THE NEXT TROUGH WILL BE DIGGING INTO THE SOUTHWEST US ON SATURDAY
AND WILL GENERATE ADDITIONAL ISENTROPIC UPGLIDE ON SATURDAY. GIVEN
THE SHALLOW NATURE OF THE MOISTURE AND COLD
TEMPERATURES...FREEZING DRIZZLE APPEARS LIKELY ALTHOUGH
ACCUMULATIONS WILL BE EXTREMELY LIGHT. ANOTHER COLD BLAST MAY MAKE
ITS WAY DOWN INTO THE US AGAIN WITH THE POLAR VORTEX STILL
SPINNING OVER SOUTHERN CANADA AND NO LETTING UP ON THE STRONG
MERIDIONAL FLOW.

&&

.PRELIMINARY POINT TEMPS/POPS...
FRIONA        38  62  20  25  10 /   0   0  10  50  60
TULIA         37  63  21  25  11 /   0   0  20  30  60
PLAINVIEW     38  66  22  26  13 /   0   0  30  30  60
LEVELLAND     42  67  28  30  16 /   0   0  30  40  60
LUBBOCK       40  69  27  29  16 /   0   0  30  50  60
DENVER CITY   43  65  34  37  17 /   0   0  20  50  60
BROWNFIELD    43  67  29  32  17 /   0   0  30  50  60
CHILDRESS     35  61  25  28  13 /   0   0  20  30  60
SPUR          41  73  26  29  14 /   0   0  30  50  60
ASPERMONT     43  76  27  30  16 /   0   0  40  50  60

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM THURSDAY MORNING THROUGH FRIDAY MORNING
FOR THE FOLLOWING ZONES: TXZ021>044.

&&

$$

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