FXUS64 KLUB 031202
AFDLUB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
602 AM CST THU DEC 3 2009
.AVIATION...
CONCERNS FOR AVIATION WEATHER THIS PERIOD WILL REVOLVE AROUND THE
PROSPECTS FOR DETERIORATING CONDITIONS WITH PERIODS OF SNOW LATER
TODAY. THE ONSET OF PRECIPITATION AND LOWER CIGS/VIS PRESENT A
FORECAST CHALLENGE FOR KLBB...WITH AN AREA OF LIGHT SNOW NOW JUST
70NM NORTHWEST OF THE TERMINAL. THIS ACTIVITY MAY GRADUALLY SHIFT
TOWARD KLBB BY 16-19Z. HOWEVER BETTER PROSPECTS FOR SNOW AND MVFR
CONDITIONS WILL EXIST THIS EVENING AFTER 01Z. THE NEED FOR AN
AVIATION WEATHER WARNING FOR ONSET OF ACCUMULATING SNOW AT KLBB
WILL BE MONITORED LATE TODAY/THIS EVENING. PROSPECTS FOR MVFR/SNOW
AT KCDS ARE LOWER.
&&
.PREV DISCUSSION... /ISSUED 353 AM CST THU DEC 3 2009/
SHORT TERM...
PROSPECTS FOR SNOW AND COLD TEMPERATURES HIGHLIGHT THE SHORT TERM
FORECAST PERIOD THIS ISSUANCE. WILL POST A WINTER WEATHER ADVISORY
FOR THE WESTERN SOUTH PLAINS.
LIGHT SNOW APPEARS TO ALREADY BE BEGINNING OVER THE EXTREME
SOUTHWESTERN PANHANDLE. THIS AS THE ONSET OF LIFT/ASCENT ASSOCIATED
WITH THE ENTRANCE REGION OF A DEVELOPING SOUTHERN PLAINS UA JET
SEEMS TO BE MORE PRONOUNCED AND EARLIER THAN DEPICTED BY ANY OF THE
NWP SOLUTIONS. THE LIKELIHOOD OF 1+ INCH SNOW ACCUMULATIONS SEEMS
HIGH OVER THE NORTHWESTERN ZONES BY 18Z. THE FOCUS FOR ADDITIONAL
LIGHT SNOW ACCUMULATIONS SHOULD SHIFT SOUTHWARD WITH TIME LATE TODAY
AND TONIGHT...AS SAID JET DYNAMICS SHIFT SOUTHWARD AND AS A
SHARPENING SHORTWAVE TROUGH PROPAGATES SOUTHEASTWARD WITHIN THE
AMBIENT NORTHWESTERLY FLOW ALOFT OVER NEW MEXICO. GFS/SREF SOLUTIONS
DEPICT THE ONSET OF LOWER TROPOSPHERIC FRONTOGENETICAL FORCING AND
BANDED INSTABILITY OVER THE SOUTHWESTERN SOUTH PLAINS AND ADJACENT
AREAS OF NEW MEXICO AND THE PERMIAN BASIN AS THIS OCCURS BETWEEN
06-12Z. THIS MAY RESULT IN LOCALLY HIGHER SNOW ACCUMULATIONS THERE
OVERNIGHT THAT COULD APPROACH 3+ INCHES. THIS IS ALSO THE TIMEFRAME
WHEN MORE WIDESPREAD LIGHT ACCUMULATIONS MAY OCCUR ACROSS MOST AREAS
ON THE CAPROCK...SO THE ADVISORY AREA WILL NEED TO MONITORED FOR
POSSIBLE EXPANSION. SNOW SHOULD TAPER OFF DURING THE 12-18Z
TIMEFRAME FRIDAY AS THE UA TROUGH AXIS TRANSLATES EAST.
AWAY FROM SNOW...TODAY/S COLD TEMPERATURES ARE VERY NOTEWORTHY.
DAYTIME HIGH TEMPERATURE FORECASTS WILL BE PROBLEMATIC DUE TO
COMPLEXITIES OF PRECIPITATION AND CLOUD COVER...BUT CONTINUED CAA
PERSISTS AND DAYTIME HIGHS MAY ACTUALLY STRUGGLE TO REACH FREEZING
FOR MOST LOCATIONS ON THE CAPROCK. OVERNIGHT LOWS WILL BE IN THE
TEENS FOR MANY SITES.
LONG TERM...
THE WINTRY WEATHER EVENT WILL BE DRAWING TO AN END BY FRIDAY
AFTERNOON...AS THE ELONGATED TROUGH STRETCHING FROM THE GREAT LAKES
REGION TO FAR WEST TEXAS WILL CONTINUE TO PROPAGATE EAST /ALONG WITH
THE SNOW POTENTIAL/. THUS...MOST OF THE SNOW WILL SHIFT ACROSS THE
FAR SOUTHERN SOUTH PLAINS DURING THE AFOREMENTIONED TIME-FRAME...AND
WELL SOUTH/EAST OF THE AREA BY FRIDAY NIGHT. A CANADIAN AIRMASS WILL
PREVAIL CREATING HIGHS GENERALLY IN THE 30S ON FRIDAY.
UPPER LEVEL RIDGING ACROSS THE WESTERN CONUS WILL MOVE TOWARDS THE
REGION FRIDAY NIGHT/EARLY SATURDAY MORNING...HOWEVER A PACNW
SYSTEM WILL AID IN FLATTENING THE RIDGE INDUCING A MORE ZONAL FLOW
BY SATURDAY AFTERNOON. INCREASING MID TO UPPER LEVEL THICKNESSES
AND SFC LEE TROUGHING NEAR THE PANHANDLES...WILL PROVIDE FOR
SLIGHTLY WARMER TEMPS /ALBEIT STILL BELOW SEASONAL AVG/ AND SLIGHTLY
BREEZY SOUTHERLY SFC WINDS RESPECTIVELY. THEREAFTER...THERE IS A
BIT OF A DISCREPANCY AMONGST THE GFS AND ECMWF SOLUTIONS REGARDING
THE SYNOPTIC PATTERN EVOLUTION THROUGH THE END OF THE EXTENDED
FORECAST PERIOD. THE GFS MODEL DISPLAYED THE AFOREMENTIONED PACNW
SYSTEM MOVING ACROSS THE CENTRAL PLAINS...DIVING A DRY COLD
FRONTAL BOUNDARY ACROSS THE CWA BY SUNDAY AFTERNOON. ANOTHER UA
LOW WILL DIVE SE ACROSS THE DESERT SW...SWEEPING IN A COOLER
CANADIAN AIRMASS TUESDAY/WEDNESDAY. MODEL SOUNDINGS EXHIBITED MOISTENING
PROFILES WITH PWATS NEARING 0.70 INCHES...INCREASING SYNOPTIC LIFT AND
A MIXTURE OF RAIN/SNOW PROFILES /WITH NORTHERN AND HIGHER
ELEVATION AREAS FAVORING THE SNOW PROFILE/. A NORTHERLY COLD FRONT
WILL ACCOMPANY THE UA LOW PRESENTING THE POTENTIAL FOR GUSTY
CONDITIONS. BY THURSDAY...A SLIGHTLY AMPLIFIED ZONAL FLOW ALOFT
WILL MOVE ACROSS THE SOUTH PLAINS. THE ECMWF ON THE HAND DIVES THE
FROPA ACROSS THE CWA MONDAY MORNING /VERSUS SUNDAY/...KEEPING THE
NEXT PACNW SYSTEM ACROSS THE CENTRAL PLAINS. THE ECMWF SOLUTIONS
DOES DISPLAY GUSTY CONDITIONS TUESDAY NIGHT...BUT IN THE FORM OF A
WESTERLY/DOWNSLOPE COMPONENT AS ZONAL FLOW PREVAILS...BEFORE A
GUSTY COLD FRONT MOVES ACROSS THE CWA WEDNESDAY MORNING.
THUS...THE BEST LIFTING MECHANISMS WILL REMAIN NORTH WITH THIS
SOLUTION...KEEPING THE BEST PRECIP ACROSS THE PANHANDLES/CENTRAL
PLAINS. BY THURSDAY...IT LOOKS SIMILAR TO THE GFS MODEL
DISPLAYING A SLIGHTLY AMPLIFIED ZONAL FLOW ACROSS THE REGION...AS
EMBEDDED DISTURBANCES MOVES NEAR/ACROSS THE SOUTH PLAINS. WILL
THEREFORE MAINTAIN A DRY FORECAST BEGINNING FRIDAY NIGHT...DUE TO
MODEL INCONSISTENCY ATTM.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 25 14 30 18 45 / 60 50 10 0 0
TULIA 27 17 34 19 45 / 40 40 10 0 0
PLAINVIEW 30 18 33 21 44 / 40 50 20 0 0
LEVELLAND 30 17 30 18 42 / 30 60 30 0 0
LUBBOCK 33 18 31 20 42 / 30 50 30 0 0
DENVER CITY 32 18 29 18 42 / 30 60 20 0 0
BROWNFIELD 33 18 29 18 42 / 30 60 30 0 0
CHILDRESS 37 21 41 22 47 / 20 20 10 0 0
SPUR 35 20 33 23 45 / 20 40 30 0 0
ASPERMONT 39 23 33 24 47 / 10 40 30 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST FRIDAY FOR
THE FOLLOWING ZONES: TXZ021-022-027-028-033-034-039-040.
&&
$$
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