FXUS64 KLUB 081403
AFDLUB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
803 AM CST TUE DEC 8 2009
.UPDATE...
THE LATEST SATELLITE/RADAR TRENDS SHOW AN EXPANDING PRECIP SHEILD
OVER NORTHEASTERN NEW MEXICO ASSOCIATED WITH ENHANCED FORCING/
ASCENT IMMEDIATELY IN ADVANCE OF THE EJECTING SHORTWAVE TROUGH.
FORECAST MODELS INDICATED SOME MID LEVEL MOISTURE TRANSITING THE
NORTHERN FA...WITH VERY LIGHT QPF BEING GENERATED BY THE NAM AS
THE FAR SOUTHERN END OF THIS ENHANCEMENT TRANSLATES OVER THE PANHANDLES/
NORTHERN SOUTH PLAINS. WE HAVE UPDATED THE FORECAST PRODUCTS TO INDICATE
LIGHT FREEZING RAIN/SNOW DURING THE 15-18Z TIMEFRAME.
OTHERWISE...EXPECTATIONS FOR A HIGH-END WIND EVENT REMAIN VALID.
OBS SHOW SEVERE WINDS BEGINNING OVER THE MOUNTAINS /83 MPH IN THE
GUADALUPE MOUNTAINS/...AND REGIONAL PROFILERS SHOW VEERING/INCREASING
WINDS. THE ONSET OF HIGH WINDS SHOULD OCCUR DURING THE 17-19Z TIMEFRAME.
&&
.PREV DISCUSSION... /ISSUED 554 AM CST TUE DEC 8 2009/
AVIATION...
COMPLEX SET OF ISSUES TODAY. SUB FREEZING TEMPERATURES WITH
FREEZING DRIZZLE/FREEZING FOG SHOULD CONTINUE UNTIL THE 16Z-17Z
TIMEFRAME. IN ADDITION TO LOW CIGS/VSBY...A THIN LAYER OF ICE HAS
ACCUMULATED ON ROADWAYS ACROSS THE REGION AND THIS HAZARD WILL LIKELY
PRESENT AN AVIATION HAZARD THROUGH LATE MORNING. AROUND THE TIME
THAT FREEZING TEMPERATURES BREAK...WINDS WILL BEGIN TO PICK UP AS
115KT 500MB AND 70KT 700MB WINDS MIX TO THE SURFACE...PARTICULARLY
AT KLBB WITH VERY STRONG WESTERLY FLOW. ALTHOUGH SFC CONDITIONS
ARE VERY MOIST EARLY THIS MORNING...BLOWING DUST WILL LIKELY
REDUCE VISIBILITIES DURING THE PEAK WIND PERIOD THIS AFTERNOON
BEFORE A COLD FRONT PUSHES INTO THE AREA TONIGHT. 26
SHORT TERM...
SIGNIFICANT WEATHER IMPACTS ARE POSSIBLE ON THE SOUTH PLAINS TODAY.
VAPOR IMAGERY SHOWS A POTENT UA SHORTWAVE TROUGH NOW EJECTING OVER
THE FOUR CORNERS REGION ACCOMPANIED BY A BROAD AREA OF SUBSIDENT
DRYING. AREA OBS/PROFILERS ARE HINTING AT THE INITIAL RESPONSE TO
HEIGHT/PRESSURE FALLS...EVIDENT BY A GRADUAL VEERING OF CURRENT
UPSLOPE WINDS AND THE NORTHWARD ADVECTION OF NON-FREEZING TEMP...
NOW SOUTH OF A PECOS-SAN ANGELO LINE. IT IS NOTABLE THAT TEMPS
INCREASED FROM 30 TO 58 DEGREES BETWEEN 06-08Z AT ALPINE. THESE
TRENDS WILL PERSIST/INTENSIFY THROUGH MID MORNING AS WARM/MOIST
ADVECTION INCREASES IN ADVANCE OF THE APPROACHING UA SYSTEM. THE
CURRENT UPGLIDE IS BEST ANALYZED IN THE 285-295K ISENTROPIC LAYER...
WHICH SHOWS A RAPID TRANSITION TOWARD NEUTRAL...THEN AN ONSET OF
INTENSE DOWNGLIDE DURING THE 15-18Z TIMEFRAME. THIS IS WELL
CORRELATED TO NAM/RUC SOUNDINGS WHICH DEPICT BREAKING STRATUS/
WARMING SURFACE TEMPS BETWEEN 15-17Z. THUS...EXPECT A CONTINUATION
OF THE ONGOING LIGHT...BUT DANGEROUS...FREEZING DRIZZLE AND ICE
ACCUMULATIONS WHICH HAVE REPORTEDLY RESULTED IN NUMEROUS AUTO
ACCIDENTS AND FALL INJURIES ACROSS THE CITY ALREADY. THIS WARRANTS
AN EXTENSION OF THE WINTER WEATHER ADVISORY UNTIL 10 AM.
THE COMPLEXITIES OF TODAY/S WEATHER SITUATION WILL NOT END WITH THE
EXPIRATION OF THE WINTER WEATHER ADVISORY. INSTEAD...THE ONSET OF
CLEARING/WARMING WILL PROMOTE A DRAMATIC INCREASE IN WINDS BY
MIDDAY/EARLY AFTERNOON. THIS AS THE AFOREMENTIONED SHORTWAVE TROUGH
EJECTS OVER THE SOUTHERN ROCKIES/PLAINS AND RESULTS IN STRONG
CYCLOGENESIS OVER THE PANHANDLES. AREA PROFILERS SUGGEST THE WELL
ANTICIPATED AND INTENSE MID-UA WIND MAXIMA ARE INCOMING ATTM...AND
WILL OVERSPREAD THE SOUTH PLAINS WITH THE ONSET OF DRY SLOT
DOWNGLIDE BETWEEN 16-19Z. A 76 MPH GUST WAS OBSERVED JUST BEFORE 11Z
IN THE GUADALUPE MOUNTAINS...AND THIS MAY PROVIDE AN INDICATION OF
WHAT/S IN STORE FOR THE SOUTH PLAINS LATER TODAY. CURRENT PROGS
DEPICT A 115KT 500MB JET TRANSLATING OVER THE CENTRAL/SOUTHERN SOUTH
PLAINS THIS AFTERNOON...AND HEIGHT/MSLP GRADIENTS SUPPORT 35-45MPH
WINDS WITH 65+MPH GUSTS PER LOCAL GUIDANCE. THE HIGHEST WINDS SHOULD
FAVOR THE SOUTHERN FA GIVEN THE PROGGED TRAJECTORY OF WIND MAXIMA
ALOFT. SIMILAR JET STRUCTURES IN THE PAST HAVE RESULTED IN
SIGNIFICANT DUST PLUMES...BUT THIS SEEMS SOMEWHAT UNCERTAIN GIVEN
MOIST TOP SOILS. TRENDS SHOULD BE MONITORED FOR POTENTIAL DUST STORM
HEADLINES. IT CURRENTLY APPEARS THAT THE WIND THREAT IS SLIGHTLY
LESS OVER THE NORTHEASTERN ZONES...THUS WIND ADVISORIES SEEM
APPROPRIATE THERE. HOWEVER A RESURGENCE OF THE MODIFIED ARCTIC AIR
IS EXPECTED TONIGHT IN THE WAKE OF THE PASSING TROUGH AXIS...AND
POST FRONTAL MSLP GRADIENTS/WINDS MAY SUPPORT A SECONDARY PERIOD OF
ADVISORY LEVEL WIND SPEEDS THERE DURING THE 00-06Z TIMEFRAME.
LONG TERM...
POTENT UPPER LEVEL WILL PASS JUST NORTH OF THE AREA TUESDAY BEFORE
ANOTHER BATCH OF ENERGY WILL ROUND THE UPPER TROUGH ON WEDNESDAY.
BY LATE THURSDAY...FLOW WILL TRANSITION TO ZONAL BEFORE SUBTLE
TROUGHINESS SETS IN FOR THE WEEKEND EMBEDDED IMPULSES APPROACHING
SATURDAY AND SUNDAY THROUGH THE END OF THE FCST PERIOD.
WESTERN PERIPHERY OF COLD FRONT WILL USHER COOLER AIR BACK INTO THE
AREA ON WEDNESDAY. AS THIS THE AIRMASS IN PLACE EARLY TUESDAY
MORNING...AFTER SOME MODIFICATION...WILL BE RETURNING...HAVE
UNDERCUT GUIDANCE FOR HIGH TEMPS. FCST SOUNDINGS DO NOT APPEAR TO
SUPPORT DRIZZLE AT THIS TIME...BUT...THIS AIRMASS HAS NOT BEEN
HANDLED WELL BY GUIDANCE AND WE WILL KEEP AN EYE ON POTENTIAL FOR
APPROACHING SATURATION IN THE BOUNDARY LAYER.
SATURDAY AND EVEN MORE SO ON SUNDAY GUSTY WESTERLY WINDS ARE
EXPECTED PARTICULARLY ACROSS THE NORTHWESTERN ZONES. OTHERWISE
SEASONABLE AND DRY CONDITIONS WILL PREVAIL WITH INTERMITTENT
CLOUDINESS AS DISTURBANCES PASS NEARBY.
FIRE WEATHER...
A FIRE WEATHER THREAT WAS NOT MENTIONED IN TODAY/S HAZARD PRODUCTS.
THIS IN SPITE OF A FAVORABLE SYNOPTIC PATTERN KNOWN TO SUPPORT
EXTREMELY CRITICAL FIRE WEATHER CONDITIONS AND ANTICIPATIONS OF VERY
STRONG WINDS LATER TODAY. HOWEVER...WIDESPREAD FREEZING DRIZZLE AND
FOG HAVE RESULTED IN EXCELLENT OVERNIGHT RELATIVE HUMIDITY
RECOVERIES AND A DAMPENING OF AREA VEGETATIVE FUELS. SUBSEQUENTLY...
AFTERNOON RELATIVE HUMIDITY MINIMA ARE EXPECTED TO BOTTOM OUT
BETWEEN 25 AND 35 PERCENT...WELL SHY OF CRITICAL VALUES. ALTHOUGH
THESE COMBINATIONS OF WIND AND HUMIDITY HAVE BEEN CORRELATED TO A
LOW PROBABILITY OF SIGNIFICANT WILDFIRE ACTIVITY PER LOCAL STUDIES...
THE EXTENT OF OVERNIGHT RECOVERY AND RESULTANT MODERATE AMBIENT FIRE
DANGER SHOULD LIMIT THE OVERALL FIRE WEATHER THREAT.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 51 13 41 14 43 / 20 10 0 0 0
TULIA 52 14 35 17 39 / 20 10 0 0 0
PLAINVIEW 51 16 36 20 44 / 20 10 0 0 0
LEVELLAND 59 20 41 21 51 / 10 10 0 0 0
LUBBOCK 57 19 38 22 49 / 10 10 0 0 0
DENVER CITY 62 22 45 26 51 / 10 10 0 0 0
BROWNFIELD 60 23 42 22 52 / 10 10 0 0 0
CHILDRESS 54 16 32 18 38 / 20 10 0 10 0
SPUR 59 24 37 22 45 / 10 10 0 0 0
ASPERMONT 63 28 37 21 46 / 10 10 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: TXZ021>024-027>030-033>037-039>043.
WINTER WEATHER ADVISORY UNTIL 10 AM CST THIS MORNING FOR THE
FOLLOWING ZONES: TXZ021>044.
WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: TXZ025-026-031-032-038-044.
&&
$$
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