Area Forecast Discussion
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FXUS64 KLUB 170954
AFDLUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
354 AM CST WED DEC 17 2014

.SHORT TERM...
WEAK SOUTHEASTERLY SURFACE FLOW WAS IN PLACE THIS MORNING ACROSS THE
REGION WITH AMPLE LOW...MID...AND HIGH CLOUD COVER COMING IN FROM
DIFFERENT DIRECTIONS.  LOW LEVEL CLOUDS WERE DEVELOPING AS A FAIRLY
STRONG LOW LEVEL JET HAS DEVELOPED AND IS HELPING TO TRANSPORT
MOISTURE IN FROM THE SOUTH TO SOUTHWEST AROUND 3KFT.  MID AND HIGH
CLOUDS WERE STREAMING IN FROM THE SOUTHWEST ON THE SUBTROPICAL JET
THAT WAS MOVING ACROSS TEXAS AHEAD OF A SHORTWAVE LOCATED OVER THE
GULF OF BAJA.  THIS SHORTWAVE WAS MOVING EAST AND WILL CONTINUE TO
MOVE ACROSS THE AREA THROUGH THE DAY.  WEAK AND BROAD LIFT UNDER THE
SUBTROPICAL JET HAS RESULTED IN THE DEVELOPMENT OF VERY LIGHT
PRECIPITATION ABOVE A DEEP DRY LAYER CENTERED AROUND 700HPA.  THIS
PRECIPITATION WILL MOISTEN THE COLUMN FROM THE TOP DOWN THROUGH THE
DAY WHICH WILL EVENTUALLY ALLOW SOME OF THE PRECIPITATION TO REACH
THE GROUND.

UNFORTUNATELY THE TIMING OF THE SYSTEM MEANS THAT THE BEST CHANCES
FOR PRECIPITATION REACHING THE GROUND WILL BE ACROSS THE ROLLING
PLAINS THROUGH THE MORNING AND AFTERNOON.  COLUMN ACROSS THE SOUTH
PLAINS WILL NOT HAVE ENOUGH TIME TO FULLY MOISTEN TO ALLOW LIGHT
PRECIPITATION TO REACH THE GROUND BEFORE THE SHORTWAVE IS EAST OF
THIS PART OF THE FORECAST AREA.  ROLLING PLAINS WILL SEE A LONGER
PERIOD OF TIME TO MOISTEN THE COLUMN AHEAD OF THE SHORTWAVE AND HAVE
KEPT SLIGHT CHANCE POPS IN PLACE FOR THIS MORNING AND THEN TAPER IT
DOWN THROUGH THE AFTERNOON.  CANNOT RULE OUT AN ISOLATED CLAP OF
THUNDER BUT MOST PRECIPITATION WILL BE RAIN SHOWERS AS MEAGER
INSTABILITY ALOFT WILL BE IN PLACE AS INDICATED BY ELEVATED CAPE
VALUES AT OR UNDER 500 J/KG AND NEARLY MOIST ADIABATIC MODEL
SOUNDING PROFILES. CLOUDY SKIES WILL REMAIN IN PLACE ACROSS THE
ROLLING PLAINS THROUGH MUCH OF THE DAY WHICH IS PART OF THE REASON
FOR THE LIMITED AMOUNTS OF INSTABILITY...AND THIS WILL ALSO HELP
TO KEEP HIGH TEMPERATURES IN THE UPPER 40S TO LOWER 50S. CLOUDS
MAY BREAK ENOUGH ACROSS THE SOUTH PLAINS TO HELP BOOST TEMPS
GENERALLY IN TO THE MID 50S WITH SOME NEAR 60 READINGS ACROSS THE
FAR SOUTHWESTERN SOUTH PLAINS.

SLOWLY CLEARING SKIES THROUGH TONIGHT AND DRIER AIR AT THE SURFACE
BEHIND A WEAK PACIFIC FRONT THAT WILL PUSH THROUGH THIS EVENING WILL
HELP TO DROP MIN TEMPERATURES THURSDAY TO NEAR OR JUST UNDER
FREEZING ACROSS THE WESTERN SOUTH PLAINS.  CLOUDS WILL HANG ON LONG
ENOUGH ACROSS THE ROLLING PLAINS TO KEEP MIN TEMPS IN THE UPPER 30S
TO LOWER 40S BY THURSDAY MORNING.

JORDAN

&&

.LONG TERM...
THE LATEST ITERATION OF SHORT AND MEDIUM RANGE GUIDANCE CONTINUE TO
ADVERTISE A PROGRESSIVE WEATHER PATTERN WITH THE PASSAGE OF SOME
FORM OF AN UPPER LEVEL TROUGH EVERY COUPLE OF DAYS OR SO.
UNFORTUNATELY...WITH THIS QUICK WAVE TRAIN...IT WILL BE DIFFICULT
FOR ANY GIVEN DISTURBANCE TO PULL SUFFICIENT MOISTURE INTO NORTHWEST
TEXAS TO BRING MORE THAN BRIEF AND RELATIVELY MEAGER PRECIPITATION
CHANCES TO WEST TEXAS.

THE MOST NOTABLE UPPER LEVEL DISTURBANCES CURRENTLY FORECAST IN THE
EXTENDED IS CURRENTLY OFF THE COAST OF THE PACIFIC NORTHWEST AND
BRITISH COLUMBIA. A PORTION OF THIS ELONGATED VORTICITY MAXIMUM IS
PROGGED TO DIVE SOUTHEASTWARD ACROSS CALIFORNIA TONIGHT AND EARLY
THURSDAY BEFORE SWINGING MORE EASTWARD THURSDAY NIGHT INTO FRIDAY.
UNFORTUNATELY FOR THOSE WANTING PRECIPITATION...THE MOST RECENT
TRENDS TAKE THE BULK OF THE ENERGY/LIFT WITH THIS SYSTEM TO OUR
SOUTH...FROM THE BIG BEND THROUGH CENTRAL TEXAS THURSDAY NIGHT INTO
FRIDAY. THE SOUTH PLAINS WILL STILL RECEIVE A GLANCING SHOT OF LARGE
SCALE LIFT...BUT IT APPEARS MUCH OF THIS WILL BE WASTED AS IT WILL
BE SATURATING THE TROPOSPHERE FROM THE TOP DOWN. BY THE TIME THE
LOWER ATMOSPHERE BECOMES CONDUCIVE FOR PRECIPITATION THE LIFT WILL
LIKELY BE SUBSIDING. NOT SURPRISINGLY...THE NWP HAS REALLY BACKED
OFF ON QPF LOCALLY...WITH THE BULK OF THE PRECIPITATION NOW
EXPECTED TO ELUDE US TO THE SOUTH AND SOUTHEAST. STILL...WE COULD
SEE A FEW SHOWERS IN THE AREA LATE THURSDAY NIGHT INTO
FRIDAY...BUT GIVEN THE TRENDS WE HAVE REDUCED POPS DOWN INTO THE
SLIGHT CHANCE CATEGORY FOR ALL BUT THE FAR SOUTHEAST ZONES...WHERE
CHANCE POPS WERE MAINTAINED. JUST ENOUGH COLD AIR COULD WORK INTO
THE NORTHWEST ZONES EARLY FRIDAY TO BRING A RISK OF A LITTLE
WINTRY PRECIP...THOUGH THE ODDS OF ANY PRECIP AT ALL NOW APPEAR TO
BE QUITE LOW. ANY PRECIP CHANCES SHOULD QUICKLY SHIFT EAST OF THE
AREA DURING FRIDAY AFTERNOON BEHIND THE DEPARTING SHORTWAVE
TROUGH.

THE NEXT DISTURBANCE IS NOW PROJECTED TO PASS AS AN OPEN TROUGH LATE
THIS WEEKEND /SO MUCH FOR A SLOW MOVING CLOSED LOW ADVERTISED IN THE
GUIDANCE A FEW DAYS AGO/...THOUGH LIFT AND MOISTURE APPEAR
UNIMPRESSIVE WITH IT AND THE LATEST BLENDED GUIDANCE HAS DROPPED
POPS BELOW 15 PERCENT...WHICH APPEARS TO BE A VALID TREND. ANOTHER
UPPER LEVEL TROUGH IS THEN EXPECTED TO DIVE THROUGH THE CENTRAL OR
SOUTHERN HIGH PLAINS MONDAY NIGHT AND TUESDAY. THIS SYSTEM WILL ALSO
BE SHORT ON MOISTURE...THOUGH THE DEEPER ECMWF DOES GENERATE A
LITTLE LIGHT QPF AS IT PASSES. THIS APPEARS A BIT OPTIMISTIC /THOUGH
NOT OUT OF THE QUESTION/...AND AT THIS POINT WE HAVE MAINTAINED
SUB-MENTIONABLE POPS FOR THE DAY 7 FORECAST.

TEMPERATURES SHOULD BE NEAR AVERAGE ON THURSDAY...PERHAPS SEVERAL
DEGREES ABOVE AVERAGE ACROSS THE CENTRAL/SOUTHERN ZONES AHEAD OF A
BACKDOOR COLD FRONT. THIS FRONT WILL MOVE THROUGH LATE THURSDAY INTO
THURSDAY NIGHT DROPPING READINGS SLIGHTLY BELOW AVERAGE TO CLOSE OUT
THE WEEK. CLEARING SKIES AND A RETURN TO SOUTHERLY TO WESTERLY
SURFACE WINDS WILL PROVIDE A PLEASANTLY MILD WEEKEND AND WE HAVE
TRENDED FORECAST HIGHS A COUPLE DEGREES HIGHER THAN THE SUPERBLEND
OUTPUT. IT APPEAR MONDAY WILL THEN BE THE WARMEST OF THE DAYS AS
DOWNSLOPE FLOW STRENGTHENS IN ADVANCE OF THE NEXT UPPER TROUGH. WE
HAVE EDGE FORECAST HIGHS INTO THE LOWER AND MIDDLE 60S...THOUGH
DEPENDING HOW THINGS PLAY OUT SOME SPOTS COULD PUSH TOWARD THE 70
DEGREE MARK. A COLD FRONT OF PACIFIC ORIGIN WILL FOLLOW MONDAY
NIGHT...KNOCKING TEMPERATURES BACK TO AROUND AVERAGE. BEYOND
THAT...THE 00Z GFS AND ECMWF CURRENTLY SUGGEST A BUILDING RIDGE
ALONG THE WEST COAST BY THE SECOND HALF OF NEXT WEEK. IF THIS WERE
TO COME TO FRUITION WEST TEXAS COULD RECEIVE THE GIFT OF MUCH
COLDER AIR WITH SOURCES NORTH OF THE ARCTIC CIRCLE /NEAR THE NORTH
POLE?/ SOMETIME AROUND CHRISTMAS.

&&

.PRELIMINARY POINT TEMPS/POPS...
FRIONA        52  30  51  29  48 /  10   0  10  20  10
TULIA         49  33  49  30  47 /  10   0  10  20  20
PLAINVIEW     51  33  52  31  48 /  10   0  10  20  20
LEVELLAND     57  33  57  31  51 /  10   0  10  20  20
LUBBOCK       54  35  57  32  51 /  10   0  10  20  20
DENVER CITY   59  35  59  34  53 /  10   0  10  20  20
BROWNFIELD    58  35  58  33  51 /  10   0  10  20  20
CHILDRESS     47  36  53  35  49 /  20  10  10  20  20
SPUR          52  37  59  34  50 /  20  10  10  30  20
ASPERMONT     52  40  62  39  50 /  20  10  10  30  30

&&

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

$$

14/23





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