FXUS64 KLUB 052340
AFDLUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
540 PM CST SAT DEC 5 2009

.AVIATION...
VFR WITH SURFACE TROUGH AND HIGH CLOUDS PRESENT ONLY MINOR CONCERNS
THIS FORECAST. OTHERWISE WE CONTINUE TO MONITOR SHALLOW LOW LEVEL
MOISTURE THAT MAY ADVECT OFF REMAINING SNOW COVER IN EASTERN NEW
MEXICO OVERNIGHT. APPEARS STILL THAT OUR WRF/NAM MODEL WAS BADLY
OVERLY COOL AND HUMID FOR THE TIME PERIOD VALID 21Z-00Z AND THUS
IS MOSTLY DISCARDED...WITH LEAN INSTEAD TOWARD THE LATEST RUC RUN.
FOR THIS TAF PACKAGE THEREFORE WE WILL RETAIN THE PREVIOUS FORECAST
INDICATING ONLY PATCHY FOG/STRATUS LATER TONIGHT. RMCQUEEN

&&

.PREV DISCUSSION... /ISSUED 319 PM CST SAT DEC 5 2009/ 

SHORT TERM...
CHALLENGES THIS DAY REVOLVE AROUND LOW CLOUD/FOG POTENTIAL OVERNIGHT 
FROM SHALLOW MOISTURE OFF THE MELTING SNOW IN SE NM AND THE NEXT 
ITERATION OF COOLER AIR THAT WILL ATTEMPT TO SLIP IN FROM THE NORTH 
SUNDAY. 

A SFC COLD FRONT WAS JUST MOVING INTO NE CO AS OF 20Z...BUT IT IS 
PROGGED TO CONTINUE STEADILY SOUTHWARD THROUGH THE NIGHT...LIKELY 
ENDING UP NEAR OR INTO THE NORTHERN ZONES BEFORE LOOSING MOMENTUM 
SUNDAY MORNING. THE FRONT WILL HOLD FAIRLY STEADY THROUGH EARLY 
AFTERNOON UNDER DECENT WSW FLOW ALOFT /IN ADVANCE OF AN APPROACHING 
S/W TROUGH/...BEFORE REGAINING A SOUTHWARD PUSH LATE IN THE DAY /AS 
THE S/W PASSES TO THE NORTH/. IN ADVANCE OF THE S/W AND COLD 
FRONT...SW SFC WINDS WILL LIGHTEN WITH TIME TONIGHT...THOUGH HIGH 
CLOUDS WILL REMAIN ABUNDANT. ALTHOUGH NORMALLY A DRYING FLOW...THE 
DOWNSLOPE SW WINDS TONIGHT WILL TEND TO PULL IN COOLER AND MOISTER 
AIR OUT OF SE NM...WHERE SOME RESIDUAL SNOW MELT HAS BEEN HOLDING 
TEMPERATURES IN THE 20S AND 30S AND BOOSTING DEWPOINTS WELL INTO THE 
20S. THE WRF-NAM SEEMS TO OVERDUE THE CURRENT AND PROJECTED 
LOW-LEVEL MOISTURE...INDICATING WIDESPREAD LOW CLOUDS AND FOG COULD 
DEVELOP ACROSS THE CAPROCK BY DAWN AS WINDS LIGHTEN. STILL...WOULD 
NOT BE SURPRISED TO SEE SOME LOW CLOUDS OR PATCHY FOG /FAVORING THE 
WESTERN ZONES/ SUNDAY MORNING...THOUGH FEEL WRF-NAM PROJECTIONS ARE 
OVERDONE. 

EXPECT A SEASONABLY COOL NIGHT TONIGHT. HIGHS ON SUNDAY WILL BE 
INFLUENCED ON THE EXACT PROGRESS OF THE FRONT AND ANY MORNING LOW 
CLOUDS. REGARDLESS...SE ZONES SHOULD SEE THE WARMEST READINGS...INTO 
THE 50S...WITH NORTHERN AND WESTERN ZONES LIKELY ONLY MAKING THE 40S 
WHERE DISCUSSED FACTORS WILL LIKELY HAVE A GREATER INFLUENCE.

LONG TERM...
FCST CONTINUES TO BE FOCUSED ON WIND POTENTIAL TUESDAY AS AN UPPER
LEVEL TROUGH MOVES ONTO THE CNTL HIGH PLAINS AND LOW/MID LEVEL
GRADIENT TIGHTENS CONSIDERABLY. STILL SOME CONCERN ABOUT HOW FAR
TO THE NORTHEAST COLD AIR WILL RETREAT...BUT IT LOOKS LIKE AT
LEAST WIND ADVISORY SPEEDS ARE A GOOD BET ON THE CAPROCK IN THE
AFTN HOURS. SOME DIFFERENCES IN TIMING OF THE UPPER TROUGH WITH A
FASTER MOVEMENT THAN CURRENTLY EXPECTED RESULING IN WINDS RAMPING
UP BEFORE NOON AND POSSIBLY SPREADING OFF THE CAPROCK. FOR NOW
WILL CONTINUE TO PLAY THINGS A BIT CONSERVATIVELY. WARM AIR TO
SPREAD NWD AHEAD OF THE SYSTEM WITH AN ADDED DOWNSLOPE COMPONENT
LIKELY TO PUSH TEMPS INTO THE 55-65F RANGE. PRECIP CHANCES STILL
LOOK VERY SMALL. THINK THAT DYNAMICS WILL BE TOO FAR NORTH AND AIR
MASS OVER THE FCST AREA TOO DRY FOR ANYTHING BEYOND A TRACE EVENT
/IF ANYTHING AT ALL/...BUT WILL ERR ON THE SIDE OF CAUTION ONE
MORE TIME AND KEEP THOSE 20 PCT POPS IN AS INHERITED FROM PREVIOUS
SHIFT. 

REMAINDER OF THE FCST LOOKS FAIRLY BENIGN. COLD AIR GETS ANOTHER
PUSH THROUGH THE FCST AREA SUNDAY NIGHT BEHIND A LOW AMPLITUDE
SHORT WAVE TROUGH MOVING ACROSS THE CENTRAL PLAINS. WILL LOOK FOR
ANOTHER PUSH BEHIND THE STRONGER TROUGH TUESDAY NIGHT DROPPING
HIGHS ABOUT 20 DEGREES FOR WEDNESDAY. END OF THE WEEK LOOKING MILD
AND POSSIBLY A BIT BREEZY AS FAST ZONAL FLOW PERSISTS ALOFT. MAY
GET A QUICK SHOT AT SOME LIGHT PRECIP TOWARD SATURDAY WITH A FAST
MOVING TROUGH IN THE ZONAL FLOW...BUT WILL KEEP POPS BELOW
MENTIONABLE LEVELS GIVEN UNCERTAINTIES WITH TROUGHS IN THE ZONAL
FLOW.

&&

.PRELIMINARY POINT TEMPS/POPS...
FRIONA        23  43  21  37  28 /   0   0   0   0  20 
TULIA         26  45  20  35  27 /   0   0   0   0  20 
PLAINVIEW     26  48  22  37  30 /   0   0   0   0  20 
LEVELLAND     24  51  24  42  32 /   0   0   0   0  10 
LUBBOCK       27  52  24  41  32 /   0   0   0   0  10 
DENVER CITY   26  49  26  47  34 /   0   0   0   0  10 
BROWNFIELD    26  52  26  44  32 /   0   0   0   0  10 
CHILDRESS     31  53  23  41  29 /   0   0   0   0  20 
SPUR          29  54  26  43  32 /   0   0   0   0  20 
ASPERMONT     30  58  28  47  33 /   0   0   0   0  20 

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

99/99/05