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000
FXUS64 KLUB 031138 AAA
AFDLUB

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LUBBOCK TX
538 AM CST TUE MAR 3 2015

.AVIATION...
LIFR CONDITIONS ARE IN PLACE AT KLBB AND KPVW DUE TO LOW
CEILINGS WHILE VFR CONDITIONS ARE IN PLACE. EXPECT TO SEE
CONDITIONS SLOWLY IMPROVE AT KLBB AND KPVW THROUGH LATE MORNING
BACK INTO VFR BY AFTERNOON. THERE WILL BE SOME SHOWERS AROUND BUT
IT REMAINS TOO EARLY TO NARROW DOWN THE TIMING. AFTER SUNSET...
EXPECT ANOTHER ROUND OF IFR TO LIFR CONDITIONS TO DEVELOP. A COLD
FRONT WILL MOVE THROUGH KCDS WHICH WILL ALSO HELP TO DROP CEILINGS
THERE DOWN INTO IFR RANGE EARLY WEDNESDAY MORNING.

JORDAN

&&

.PREV DISCUSSION... /ISSUED 420 AM CST TUE MAR 3 2015/

SHORT TERM...
A COOL AND MOIST BOUNDARY LAYER IS IN PLACE ACROSS THE REGION BUT
FOR THE FIRST TIME IN SEVERAL DAYS TEMPERATURES ARE ABOVE FREEZING.
AREAS THAT STILL HAVE SOME SNOW ON THE GROUND HAVE HAD BRIEF PERIODS
OF DENSE FOG AS TEMPERATURE AND DEWPOINT SPREAD IS VERY CLOSE OR
ZERO IN SOME CASES.  ALOFT...THE CORE OF THE SUBTROPICAL JET REMAINS
WEST OF THE REGION WITH THE EASTERN EDGE STARTING TO PUSH OVER US.
THIS HAS ALLOWED SUBTROPICAL MOISTURE TO ALSO PUSH OVER THE REGION
AS SHOWN BY WATER VAPOR SATELLITE IMAGERY...AND THE IMAGERY ALSO
SHOWS A CLOSED LOW SPINNING OFF THE SOUTHWESTERN CALIFORNIA COAST.
ALL OF THESE FEATURES COMBINED ARE MAKING FOR A COMPLICATED FORECAST
FOR TODAY INTO TONIGHT.

FIRST ISSUE WILL BE WHEN OR IF WE WILL SEE SKIES CLEAR OUT.
REGIONAL SURFACE HAND ANALYSIS SHOWS NO DRY AIR TO THE SOUTH OR
SOUTHWEST OF THE REGION WITH DEWPOINTS INCREASING INTO THE MID 40S
ACROSS THE CONCHO VALLEY AND RIO GRANDE RIVER VALLEY INTO SOUTHERN
NEW MEXICO.  WITH SURFACE WIND REMAINING OUT OF THE SOUTH TO
SOUTHWEST...A GRADUAL INCREASE IN DEWPOINTS IS EXPECTED AS THIS
AIRMASS IS ADVECTED INTO THE FORECAST AREA. JUST ABOVE THE
SURFACE...A LAYER OF DRY AIR IS IN PLACE AROUND 700 HPA.  AS THE
CLOSED LOW MOVES TOWARDS THE REGION THROUGH THE AFTERNOON AND
WEAKENS INTO AN OPEN WAVE...MID-LEVEL MOISTURE WILL INCREASE WHICH
DOES NOT FAVOR CLOUD COVER GOING AWAY EITHER.  HOWEVER AS THE TROF
APPROACHES...THE JET AXIS WILL SHIFT EAST AND SUBSIDENCE ON THE BACK
SIDE OF THE JET MAY ALLOW SOME CLEARING TO TAKE PLACE LATE IN THE
DAY.  HIGH TEMPERATURE FORECAST WILL BE A CONTEST BETWEEN SKIES
STAYING MOSTLY CLOUDY TO CLOUDY FOR THE COOL SIDE VERSUS WARM
ADVECTION THROUGH THE DAY OFFSETTING THE CLOUD COVER FOR THE WARMER
SIDE.  DID COOL TEMPERATURES ACROSS THE ROLLING PLAINS AS MODELS
WERE GOING NEAR 70 DEGREES BUT KEPT HIGHS ON THE CAPROCK CLOSE TO 60.

NEXT ISSUE THROUGH THE DAY IS PRECIPITATION.  SHORTWAVES EMBEDDED IN
THE SUBTROPICAL FLOW WILL BE MOVING ACROSS THE AREA THROUGH THE DAY
PROVIDING PERIODS OF WEAK TO MODERATE LIFT.  MODELS SHOW SHOWERS
DEVELOPING THROUGH THIS AFTERNOON WITH MORE ROBUST AMOUNTS ACROSS
THE CENTRAL PART OF THE FORECAST AREA.  HARD TO SAY WHETHER THIS
WILL HAPPEN AS LACK OF INSOLATION WILL HAMPER ANY KIND OF SURFACE-
BASED INSTABILITY AND SOUNDING PROFILES SHOW VERY MEAGER TO NON-
EXISTENT AMOUNTS OF INSTABILITY ALOFT.  DID INCREASE POPS SOME FOR
THIS AFTERNOON BUT STILL MAINTAINED ONLY ISOLATED SHOWERS FOR NOW IN
THE WEATHER GRIDS. EXPECT ANY PRECIPITATION TO REMAIN FAIRLY LIGHT
WITH ONLY A FEW HUNDREDTHS OF ACCUMULATION...BUT WILL HAVE TO WATCH
AND SEE HOW THINGS UNFOLD THROUGH THE DAY AS UNCERTAINTY IS HIGH AS
TO HOW POPS WILL DEVELOP.

PRECIPITATION CHANCES WILL CONTINUE TO INCREASE TONIGHT INTO
WEDNESDAY MORNING AS THE MAIN TROUGH MOVES TOWARDS THE REGION AND AS
A STRONG COLD FRONT STARTS TO PUSH INTO THE FORECAST AREA.  MODELS
HAVE SLOWED DOWN THE PROGRESSION OF THE FRONT AND DO NOT HAVE IT
THROUGH THE ENTIRETY OF THE FORECAST AREA UNTIL LATE IN THE DAY
WEDNESDAY. THIS IS SIGNIFICANT BECAUSE LOW TEMPERATURES WERE BROUGHT
UP ABOVE FREEZING FOR ALL BUT THE NORTHERN ROW OF COUNTIES.
PRECIPITATION SHOULD STAY LIQUID SOUTH OF A MULESHOE...TULIA...
FLOYDADA...TO PADUCAH LINE AS TEMPERATURES SOUTH OF THAT LINE WILL
BE IN THE UPPER 30S TO LOW 40S BY SUNRISE WEDNESDAY.  NORTH OF THAT
LINE...WE WILL SEE A TRANSITION FROM RAIN...TO RAIN AND SLEET...THEN
ALL SLEET...THEN FINALLY ALL SNOW BY 6 AM TOMORROW AS A FIRST GUESS.
STILL UNCERTAIN AS TO HOW FAST THE TRANSITION WILL TAKE AS MODELS
ARE STRUGGLING WITH HOW QUICKLY TO COOL THE ATMOSPHERIC COLUMN WITH
THE INITIAL SURGE OF COLD AIR INTO THE AREA.  MODELS HAVE HAD A MUCH
FASTER PROGRESSION AND STRONG COLD AIR ADVECTION THE PAST SEVERAL
RUNS SO AGAIN...THERE IS QUITE A BIT OF UNCERTAINTY ON HOW THINGS
WILL DEVELOP TOMORROW MORNING.

JORDAN

LONG TERM...
THE STORY OF THE NEVER ENDING WINTER CONTINUES AS MORE WINTRY PRECIP
IS EXPECTED WED INTO THURS. A STRONG ARCTIC FRONT WILL BE IN THE
PROCESS OF MOVING THROUGH THE FA BY SUNRISE WED. THAT MEANS BREAK
OUT THE THERMOS OF COFFEE AND HOT COCOA BECAUSE THE TEMPERATURE YOU
FEEL WHEN YOU STEP OUTSIDE THAT MORNING WILL BE THE WARMEST IT WILL
BE ALL DAY. STRONG CAA IN ADDITION TO THICK CLOUD COVER WILL ALLOW
TEMPS TO DROP STEADILY DURING THE DAY. THE WARMEST AREAS WILL BE
JUST AHEAD OF THE FRONT WHERE COMPRESSIONAL HEATING WILL KEEP
MORNING TEMPS IN THE LOW 40S. THOUGH GETTING THE HIGH TEMP IS A BIT
OF A CHALLENGE ITSELF...THE BIGGER CHALLENGE IS FORECASTING THE P-
TYPE THROUGH MID DAY. SOUNDING PROFILES SUPPORT MOSTLY FROZEN
PRECIP...SNOW AND SLEET...FOR THE NORTHERN HALF OF THE FA AFTER 6AM
AS COLD AIR ALOFT WORKS INTO THE AREA. THE SOUTHERN HALF OF THE FA
SHOULD SEE RAIN BEGINNING TO MIX WITH SLEET AND SNOW THROUGH NOON.
AFTER NOON SURFACE TEMPS SHOULD BE BELOW FREEZING ACROSS THE FA
THUS ELIMINATING THE CHANCE FOR RAIN. THE QUESTION THEN REMAINS OF
HOW LONG WILL SLEET MIX IN WITH SNOW BEFORE PRECIP IS ALL SNOW.
ALL SNOW IS EXPECTED ACROSS THE NORTHERN HALF OF THE FA...HOWEVER
MODEL SOUNDINGS DIFFER ON WHEN THE ELEVATED WARM NOSE WILL ERODE
ACROSS THE SOUTHERN HALF OF THE FA WITH THE GFS COOLING FASTER
THAN THE NAM. THE TIMING OF THE TRANSITION TO ALL SNOW WILL EFFECT
THE AMOUNT OF SNOW ACCUMULATION. FOR NOW THE FORECAST WILL REFLECT
A CHANGE TO ALL SNOW BY 3PM. CURRENT THINKING WITH SNOWFALL
AMOUNTS IS 1-2 INCHES SHOULD BE THE AVERAGE ACROSS THE FA. THE
MAIN LIFTING MECHANISM WILL BE FRONTOGENETIC FORCING.
MODELS...HOWEVER...ARE HINTING AT ENERGY FROM A SHORTWAVE MOVING
ACROSS THE REGION WHICH WOULD HELP DEVELOP BANDING LATER WED
EVENING. THIS COULD ALLOW FOR LOCALLY HIGHER SNOWFALL AMOUNTS.
THIS WOULD SUPPORT WPC ACCUMULATION GUIDANCE SHOWING THAT THE
HIGHER SIDE OF POSSIBLE SNOWFALL...THE 90TH PERCENTILE...IS IN THE
4-6 INCH RANGE. FOR NOW FORECAST AMOUNTS WILL STAY 1-2 INCHES BUT
WILL BE ADJUSTED AS NEEDED.

SNOW SHOULD BEGIN TO WIND DOWN OVERNIGHT WED INTO EARLY THURS
MORNING AS DRIER AIR FILTERS IN TO THE REGION FROM THE WEST. SURFACE
FLOW WILL BEGIN TO VEER TO THE SOUTH IN RESPONSE TO A DEVELOPING LEE
TROF WHICH WILL HELP TO WARM TEMPS INTO THE MID30S/LOW 40S THURS.
SOUTHERLY TO SOUTHWESTERLY FLOW WILL PERSIST THROUGH SATURDAY
MORNING WHEN A WEAK AND DRY FRONT IS PROGGED TO PUSH INTO THE
REGION. THIS SHOULD HAVE NO REAL AFFECT ON TEMPS FOR SATURDAY WITH
HIGHS PUSHING CLOSE TO THE 60 DEGREE MARK. A WARMING TREND WILL
CONTINUE INTO NEXT WEEK AS SURFACE FLOW BECOMES SOUTHERLY AGAIN ON
SUNDAY HELPING WARM TEMPS INTO THE 60S. DRY NORTHWESTERLY FLOW ALOFT
WILL ALLOW THE SUN...WHO HAS BEEN IN HIDING FOR SOME TIME...TO COME
OUT.

ALDRICH

&&

.PRELIMINARY POINT TEMPS/POPS...
FRIONA        59  28  28  11 /  20  30  50  20
TULIA         62  27  27  13 /  20  30  70  20
PLAINVIEW     61  32  32  13 /  20  30  70  20
LEVELLAND     62  37  37  15 /  20  30  50  30
LUBBOCK       62  35  35  14 /  20  30  60  30
DENVER CITY   61  42  42  18 /  20  30  50  30
BROWNFIELD    62  41  41  17 /  20  30  60  30
CHILDRESS     62  29  29  15 /  20  40  70  20
SPUR          65  35  35  19 /  10  40  60  30
ASPERMONT     66  40  40  22 /  10  50  60  30

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 8 AM CST THIS MORNING FOR TXZ021>024-
027>030-033>036-039>042.

&&

$$

14/51/14