Area Forecast Discussion
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FXUS64 KLUB 192334
AFDLUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
634 PM CDT SAT APR 19 2014

.AVIATION...
FIRST SHORT WAVE TROUGH EJECTED FROM A LOW OVER THE DESERT SW LIFT
NEWD ACROSS THE SOUTH PLAINS WITH AREAS OF SHRA/TSRA MOVING OUT OF
THE AREA AS WELL. LIKELY TO STAY JUST WEST OF KCDS THE FIRST TWO
HOURS OF THE TAF PERIOD. FOCUS THEN SHIFTS TOWARD LATE EVENING AS
THE NEXT WAVE IS SPARKING THUNDERSTORMS FROM THE GUADALUPE MTS OF
SRN NM TO THE BIG BEND. MODELS INCONSISTENT ON HOW FAR TO THE NE
THIS CONVECTION WILL GO. SOME THREAT TO MAKE IT TO THE FCST AREA
BUT CONFIDENCE TOO LOW ATTM TO INSERT MENTION IN EITHER TAF. NEXT
BEST CHANCE FOR PRECIP COMES SUNDAY AFTN FAVORING KCDS OVER KLBB
AND WILL RUN WITH A PROB30 THERE FOR NOW. FINALLY...POSSIBILITY OF
MVFR CIGS TOWARD 12Z FAVORING KLBB OVER KCDS.

&&

.PREV DISCUSSION... /ISSUED 341 PM CDT SAT APR 19 2014/

SHORT TERM...
WV IMAGERY SHOWS OUR UPPER LOW OF INTEREST CONTINUING TO SLOWLY MOVE
EASTWARD WHILE CONTINUING TO DRAW IN TROPICAL MOISTURE FROM THE
PACIFIC. A SHORTWAVE PUSHING NORTH AND EASTWARD IS ALSO VISIBLE ON
WV AND HAS BECOME MORE PRONOUNCED OVER THE PAST SEVERAL HOURS. THE
SHORTWAVE STRETCHES FROM SOUTHERN NM THROUGH THE PERMIAN BASIN TO
THE EDWARDS PLATEAU AND IS AIDING IN THE NUMEROUS SHOWER ACTIVITY IN
SOUTHEAST NM AND ALONG THE TX/NM STATE LINE. SHOWERS HAVE BEEN SLOW
TO MOVE EASTWARD IN PART DUE TO DRY AIR IN THE MID LEVELS. MUCH OF
THE RAIN THAT HAS FALLEN HAS BEEN MOSTLY VIRGA WITH SOME LIGHT RAIN
MAKING ITS WAY TO THE GROUND. LOOKING AT TRENDS FROM RAP ANALYSIS
TOP DOWN MOISTENING IS HAPPENING BUT NOT IN AN EXTREME HURRY. WE
SHOULD BE ABLE TO MOISTEN UP ENOUGH FOR WHEN THE SHORTWAVE MOVES
OVERHEAD LATER THIS AFTERNOON INTO THE EVENING WHICH SHOULD PROVIDE
NUMEROUS SHOWERS. I HAVE INCREASED POPS TO AROUND 60 FOR THE WESTERN
HALF OF THE FA BUT HAVE CHANGED THE WX CATEGORY TO RAIN SHOWERS WITH
A MENTION OF ISO THUNDER AS LAPSE RATES WILL BE SLOW TO STEEPEN AS
THE CENTER OF THE LOW WILL STILL BE WELL TO OUR WEST. THIS ALONG
WITH CLOUDY SKIES FOR A MAJORITY OF THE DAY HAVE LIMITED DAYTIME
HEATING AND HAVE KEPT TEMPS ON THE COOL SIDE.

RAIN SHOWERS AND THUNDERSTORMS WILL PERSIST THROUGH THE LATE EVENING
AND ACTIVITY SHOULD TAPER DOWN AFTER MIDNIGHT WHEN THE SHORTWAVE HAS
PASSED TO THE NORTH. THE NEXT FOCUS WILL BE TOMORROW AFTERNOON AND
EVENING AS THE UPPER LEVEL LOW OPENS AND THE TROF MOVES INTO THE
AREA. MODELS HAVE DIFFERED SLIGHTLY ON HOW TO HANDLE IT BUT AGREE IN
DRYLINE CONVECTION FIRING LATE TOMORROW AFTERNOON. THE MAIN
DIFFERENCE IN MODELS IS HOW FAR WEST WILL THE DRYLINE BEGIN TO
CONVECT. THE NAM/TTU WRF SHOW THE DRYLINE CONVECTING IN THE
SOUTHWESTERN TX PANHANDLE AND PUSHES SOUTHEASTWARD WHILE THE GFS
FIRES CONVECTION NEAR THE EDGE OF THE CAPROCK AND PUSHES EASTWARD.
FOR NOW I HAVE CONTINUED TO OPT FOR A BIT FARTHER WEST AS LOW LEVEL
MOISTURE WILL STILL BE AVAILABLE AND THIS SCENARIO HAS BEEN MORE
CONSISTENT WITH THE NAM/TTU WRF. CONCERNING SEVERE POTENTIAL...MID
LEVEL LAPS RATES WILL STEEPEN AS THE TROF AXIS MOVES OVERHEAD WHICH
WILL INCREASE OVERALL CAPE...BUT THE AMOUNT OF SBCAPE IS IN QUESTION
AS THE SUN WILL STRUGGLE TO PEAK THROUGH THE CLOUDS TOMORROW. THERE
MAY BE A WINDOW OF OPPORTUNITY TOMORROW FOR THE SUN TO SHINE THROUGH
HELPING TO WARM SURFACE TEMPS. MUCAPE AROUND 1000 J/KG WILL BE
ENOUGH TO TRIGGER STRONG CONVECTION ALONG THE DRYLINE. 0-6KM SHEAR
AROUND 35 TO 45 KTS WITH MARGINAL DRY AIR ALOFT WILL HELP AID IN
HAIL GROWTH PRODUCING LOW END SEVERE HAIL. SOME STRONG WINDS
REACHING SEVERE CRITERIA WILL BE POSSIBLE AS WELL...HOWEVER
WIDESPREAD SEVERE THUNDERSTORMS ARE NOT ANTICIPATED ATM AND WILL BE
ISOLATED IN NATURE. ALDRICH

LONG TERM...
THE SLOW-MOVING UPPER TROUGH WILL BE SLOWLY EXITING THE AREA
SUNDAY EVENING. INDICATIONS ARE THAT THE ATMOSPHERE WILL BE FAIRLY
WORKED OVER BY EVENING AND WITH DECREASING SFC-BASED
INSTABILITY...ANY SEVERE THREAT SHOULD DIMINISH AFTER 8 PM OR SO.
SHOWERS MAY CONTINUE ACROSS THE EASTERN AREAS INTO THE NIGHT
THOUGH...GRADUALLY DECREASING IN COVERAGE AND STRENGTH FROM WEST
TO EAST. NW FLOW IN THE WAKE OF THE TROUGH WILL OPEN THE DOOR FOR
A WEAK FRONT TO MOVE SOUTH ACROSS THE AREA MONDAY. THERE IS SOME
SUGGESTION OF SOME LIGHT SHOWERS ACROSS OUR ERN ZONES AND ALSO
PERHAPS IN THE NW...BUT WE/VE KEPT POPS BELOW MENTION FOR NOW. NOT
MUCH CHANGE IN THE FORECAST BEYOND MONDAY. SHORTWAVE RIDGING ON
TUESDAY SHOULD BRING WARMER TEMPS WHILE WINDS WILL RETURN TO A SERLY
FETCH. FAIRLY DEEP TROUGH MOVING INTO THE ROCKIES SHOULD INDUCE A
NICE LLJ TUESDAY NIGHT...AND BEGIN TO ADVECT GULF MOISTURE BACK
INTO WTX. THE GFS STILL IS PRETTY BULLISH WITH THE MOISTURE RETURN
ALL THE WAY TO THE STATE LINE OVERNIGHT AND COULD LIKELY RESULT IN
SOME MORNING LOW STRATUS ACROSS THE CWA WEDNESDAY. THE LATEST GFS
AND ECMWF REMAIN IN PRETTY GOOD AGREEMENT THAT A DRYLINE WILL FORM
SOMEWHERE ACROSS THE EASTERN HALF OF THE CWA AND BOTH CONTINUE TO
SHOW A GOOD QPF SIGNAL TO THE EAST OF THE DRYLINE WED AFTERNOON
AND EVENING. THERE IS A BIT OF A CONCERN WITH THE STRENGTH OF THE
CAP OVER THE DRYLINE...GUIDANCE IS CURRENTLY PROGGING TEMPS ONLY
IN THE LOWER/MIDDLE 80S WHICH MAY NOT BE SUFFICIENT TO BREAK THIS
CAP. WE ARE FORECASTING SOMEWHAT WARMER TEMPS BASED ON THE
PATTERN...AND WE HAVE KEPT A SLIGHT CHANCE OF TSTMS EAST OF THE
DRYLINE. DRIER AIR SHOULD SPREAD ACROSS THE AREA ON THURSDAY WITH
ANOTHER WEAK FROPA LIKELY LATE THURSDAY OR FRIDAY. QUITE A BIT OF
UNCERTAINTY IN THE FORECAST HEADING INTO NEXT WEEKEND. ANOTHER
FAIRLY DEEP TROUGH WILL FORM UP ACROSS THE WEST...BUT MODELS
DIVERGE WITH THE ECMWF SHOWING VEERED BROAD CYCLONIC FLOW OVER WTX
SHUNTING DEEP MOISTURE TO THE EAST...WHILE THE GFS SHOWS LESS OF A
WESTERLY COMPONENT AND A BETTER CHANCE OF MOISTURE HOLDING IN AND
POSSIBLY LEADING TO SOME PRECIP POTENTIAL. WE/LL KEEP THE DRY FCST
RUNNING WHILE FOLLOWING THE TRENDS.

&&

.PRELIMINARY POINT TEMPS/POPS...
FRIONA        50  74  49  77  49 /  60  20  10  10   0
TULIA         54  75  52  78  51 /  30  30  20  10   0
PLAINVIEW     54  75  54  80  52 /  40  30  20  10   0
LEVELLAND     54  76  54  80  52 /  60  20  10  10   0
LUBBOCK       56  77  55  81  53 /  60  30  20  10   0
DENVER CITY   55  78  55  79  53 /  60  20  10  10   0
BROWNFIELD    56  78  54  80  53 /  60  20  10  10   0
CHILDRESS     58  80  58  82  55 /  30  40  30  10  10
SPUR          57  79  59  84  55 /  30  40  20  10   0
ASPERMONT     58  79  60  85  56 /  30  40  30  10   0

&&

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

$$

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