FXUS64 KLUB 241128 AAA
AFDLUB
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LUBBOCK TX
528 AM CST THU DEC 24 2009
.AVIATION...
AVIATION CUSTOMERS...PRESENT WEATHER AND FREEZING PRECIPITATION SENSORS
AT KCDS HAVE GONE OUT AND ARE NOT REPORTING WEATHER TYPE. FOG/MIST
WEATHER TYPE IS DETERMINED FROM VISIBILITY ALONE AND THIS SITE IS
NOT AUGMENTED BY A PERSON SO USE REPORT WITH CAUTION. TECH WILL BE
NOTIFIED BUT HAZARDOUS DRIVING CONDITIONS MAY NOT ALLOW FOR A
QUICK FIX.
TAFS WILL REMAIN LIFR/VLIFR THROUGH THE MORNING BEFORE FINALLY
STARTING TO CLEAR OUT LATE IN THE DAY AS THE STORM SYSTEM
RESPONSIBLE FOR THE SNOW SLIDES EAST. HARD TO TELL HOW LONG LIFR
WILL REMAIN IN PLACE AT KLBB BUT RADAR DATA DOES SHOW THAT THE
HEAVIEST SNOWFALL MAY HAVE FINALLY STARTED TO SHIFT SOUTHEAST OF
THE KLBB TERMINAL. KCDS WILL LIKELY SEE LIFR/VLIFR THROUGH MUCH OF
THE AFTERNOON. LOW CONFIDENCE IN TIMING OF SYSTEM CLEARING OUT IS
REASON FOR THE TWO TEMPO GROUPS IN BOTH TAF SITES AND KLBB MAY BE
ABLE TO CLEAR OUT A BIT EARLIER THAN INDICATED. OTHER MAJOR
PROBLEM WILL BE WIND SPEEDS WHICH CONTINUE TO SLOWLY INCREASE
ACROSS THE REGION. THIS WILL CAUSE AREAS OF BLOWING SNOW THAT WILL
REDUCE VISIBILITIES BACK DOWN INTO IFR AND LIFR THROUGH MUCH OF
THE DAY.
CONDITIONS WILL DRASTICALLY IMPROVE LATE THIS AFTERNOON INTO THIS
EVENING AS WE GO VFR AND WIND SPEEDS START TO DECREASE WITH THE
DEPARTURE OF THE STORM SYSTEM TO THE EAST OF THE REGION.
JORDAN
&&
.PREV DISCUSSION... /ISSUED 347 AM CST THU DEC 24 2009/
SHORT TERM...
LATEST WATER VAPOR SATELLITE IMAGERY SHOWS THAT THE CENTER OF THE
CLOSED LOW CONTINUES TO DRIFT SOUTHWESTWARD OVER THE PERMIAN BASIN
AND CONCHO VALLEY EARLY THIS MORNING. TEMPERATURES HAVE FALLEN TO
BELOW FREEZING ACROSS ALL BUT THE FAR SOUTHEASTERN FORECAST AREA
ACCORDING TO THE WEST TEXAS MESONET OBSERVATIONS. KLBB RADAR ALSO
CONTINUES TO SHOW A PERSISTENT AREA OF MODERATE TO OCCASIONALLY
HEAVY SNOWFALL ACROSS THE CENTRAL SOUTH PLAINS. LOCALIZED BANDING
CONTINUES TO OCCUR IN THIS AREA AS WELL WHICH HAS ALSO RESULTED IN
VISIBILITIES DROPPING TO BELOW ONE HALF OF A MILE AT TIMES. A QUICK
CHECK OF THE SNOW MEASURING BOARDS AT THE FORECAST OFFICE SHOWS
ABOUT 2.5 INCHES AS OF 3 AM THIS MORNING...WITH MORE SNOW TO COME.
LOOKING AT BOTH THE GFS AND NAM...IT APPEARS THAT THE FORECAST AREA
IS SITTING RIGHT UNDERNEATH A WEAK TROWAL THAT IS HELPING TO ENHANCE
SNOWFALL RATES. ALL MODELS ALSO AGREE IN CONTINUING TO SLIDE THE
CORE OF THE LOW AWAY THROUGH THE AREA WHICH SHOULD ALLOW SNOWFALL TO
END FROM WEST TO EAST THROUGH LATE MORNING. MODELS ALSO INDICATE
THAT THE SURFACE LOW WILL CONTINUE TO DEEPEN RESULTING IN A TIGHT
PRESSURE GRADIENT OVER THE REGION. NORTH TO NORTHWESTERLY WINDS
HAVE BEEN INCREASING IN SPEED THROUGH THE EARLY MORNING AND WILL
LIKELY CONTINUE TO DO SO...RESULTING IN AREAS OF BLOWING SNOW
THROUGH THE MORNING COMMUTE. EXPECT SUSTAINED SPEEDS OF 15 TO 25
WITH OCCASIONAL GUSTS UP TO 35 MPH ACROSS THE SOUTH PLAINS...WITH
SUSTAINED 20 TO 30 OVER THE ROLLING PLAINS AND GUSTS TO 40 MPH AS
THE PRESSURE GRADIENT WILL BE TIGHTEST OVER THAT REGION.
TEMPERATURES HAVE CONTINUED TO SLOWLY FALL AS WELL AND WITH
CONTINUED COLD AIR ADVECTION EXPECTED THROUGH THE DAY...HAZARDOUS
DRIVING CONDITIONS CAN BE EXPECTED UNTIL LATE IN THE AFTERNOON.
STILL FEEL TOTAL SNOWFALL AMOUNTS IN THE WINTER STORM WARNING AREA
COULD APPROACH 3-6 INCHES...ESPECIALLY ACROSS THE CENTRAL AND
EASTERN ZONES. BIGGEST ISSUE WITH THIS IS HOW FAST SNOWFALL WILL
TAPER OFF AS THE STORM DEPARTS AND HOW MUCH MOISTURE WILL BE IN THE
SNOW. EARLY ON...FLAKES WERE RATHER LARGE AND WET BUT HAVE
TRANSITIONED OVER TO MUCH SMALLER FLAKES WITH A HIGHER SNOW TO
LIQUID RATIO. THIS WILL COMBINE WITH THE STRONGER WINDS TO MAKE IT
HARDER TO GET RAPID ACCUMULATIONS ESPECIALLY IN OPEN AREAS. WILL GO
AHEAD AND CONTINUE WINTER STORM WARNING AS IS AND LEAVE SNOWFALL
AMOUNTS IN THE GRID UNTOUCHED FOR THE MOST PART. ONLY SIGNIFICANT
CHANGE WAS TO PULL LIGHT SNOWFALL AMOUNTS FURTHER WEST FOR THE 12Z
TO 18Z TIMEFRAME TO ACCOUNT FOR SNOWFALL LINGERING THROUGH THE
MORNING.
ALSO OPTED TO DROP MAX TEMPERATURES FOR TODAY WITH ALL BUT THE
SOUTHERN SOUTH PLAINS AND ROLLING PLAINS BARELY MAKING IT ABOVE
FREEZING. EVEN THOUGH CLOUD COVER WILL START TO DECREASE FROM WEST
TO EAST LATE IN THE DAY...AMPLE COLD AIR...SNOW COVER...AND BREEZY
CONDITIONS WILL HOLD TEMPERATURES IN THE LOW TO MID 30S. ALSO WENT
RATHER CHILLY FOR TONIGHT AS SNOW COVER AND CLEAR SKIES SHOULD MAKE
FOR EXCELLENT RADIATIONAL COOLING CONDITIONS OVERNIGHT.
JORDAN
LONG TERM...
MINIMAL CHANGES MADE TO THE EXTENDED GRIDS. THE WINTER STORM
AFFECTING WEST TEXAS EARLY THIS MORNING WILL BE LONG GONE BY FRIDAY
MORNING...CENTERED NEAR MO/IL. A CLOSED LOW ASSOCIATED WITH A JET
DIVING DOWN THE SPINE OF THE ROCKIES WILL PINWHEEL AROUND THE PARENT
LOW BEFORE BEING ABSORBED WITH IT LATE FRIDAY. AS THE SECONDARY
LOW SLIDES BY TO THE NORTH IT WILL PROVIDE SOME LIFT AND ANOTHER
REINFORCING SHOT OF SFC RIDGING...BUT THE ATMOSPHERE APPEARS TOO
DRY TO SUPPORT ANY PRECIPITATION CHANCES. BELOW NORMAL
TEMPERATURES WILL BE THE RULE THROUGH THE ENTIRE FORECAST AS SFC
RIDGING IS CONTINUOUSLY REINFORCED THROUGH MUCH OF THE PERIOD.
THIS...AS WEST TEXAS REMAINS SITUATED ON THE SW PERIPHERY OF THE
LARGE MIDWESTERN STORM...WITH A SHARP RIDGE ACROSS THE WESTERN
CONUS THROUGH THE WEEKEND. THE NORTHERN PLAINS STORM WILL FINALLY
BE KICKED EASTWARD BY EARLY NEXT WEEK...AND WE WILL SEE BRIEF
SHORTWAVE RIDGING SLIDE OVER. THIS WILL ALLOW FOR A LITTLE
MODERATION ON MONDAY. THEN ATTENTION WILL TURN TO STORM SYSTEM
THAT WILL APPROACH FROM THE WEST NEXT TUESDAY. MEDIUM RANGE
GUIDANCE HAS COME INTO BETTER AGREEMENT ON THE TIMING OF THE
SYSTEM...AND GENERALLY AGREE THE PASSING WAVE WILL HAVE SUFFICIENT
LIFT/MOISTURE TO GENERATE SOME PRECIPITATION TUE/TUE NIGHT. IT
APPEARS THE PRIMARY MODE OF ANY PRECIPITATION WOULD BE SNOW GIVEN
SOME REINFORCED SFC RIDGING DROPPING IN FROM THE THE MIDWEST.
ANOTHER DISTURBANCE MAY APPROACH BY DAY 7 OR 8...BUT THE JURY IS
STILL OUT ON WHETHER IT WILL BRING APPRECIABLE PRECIPITATION
CHANCES.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 31 8 36 13 40 / 20 0 10 0 0
TULIA 30 9 34 14 39 / 20 0 10 0 0
PLAINVIEW 30 10 34 15 40 / 30 0 10 0 0
LEVELLAND 32 11 39 17 43 / 30 0 0 0 0
LUBBOCK 32 12 38 18 42 / 30 0 10 0 0
DENVER CITY 32 18 44 18 44 / 30 0 0 0 0
BROWNFIELD 33 17 41 18 44 / 30 0 0 0 0
CHILDRESS 34 13 36 18 42 / 80 0 10 0 0
SPUR 34 15 38 19 43 / 50 0 10 0 0
ASPERMONT 34 17 39 20 44 / 90 0 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL NOON CST TODAY FOR THE FOLLOWING
ZONES: TXZ022>044.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR THE FOLLOWING
ZONES: TXZ021.
&&
$$
