Area Forecast Discussion
Issued by NWS

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FXUS64 KLUB 302302
AFDLUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
602 PM CDT SAT APR 30 2016

.AVIATION...
VFR CONDITIONS ARE EXPECTED TO PREVAIL FOR MOST OF THE TAF CYCLE
AT ALL THREE TERMINALS. CIGS MAY DIP INTO THE MVFR CATEGORY EARLY
TO MID MORNING...HOWEVER CONFIDENCE IS NOT HIGH ENOUGH TO WARRANT
MENTION IN THE TAFS. SCATTERED RAIN SHOWERS WILL ALSO BE POSSIBLE
AT ALL THREE TERMINALS STARTING LATE TONIGHT/EARLY TOMORROW
MORNING WITH PVW AND LBB HAVING THE HIGHEST CHANCES OF SEEING
RAIN. GIVEN THAT RAIN SHOWERS WILL BE SCATTERED IN NATURE AND
TIMING IS UNCERTAIN A PREVAILING -RA CATEGORY IS NOT WARRANTED IN
THE TAFS. THE TAFS WILL BE AMENDED AS NEEDED FOR RAIN.

&&

.PREV DISCUSSION... /ISSUED 330 PM CDT SAT APR 30 2016/

SHORT TERM...
MODEL GUIDANCE IS IN FAIR AGREEMENT REGARDING HOW THE UPPER LOW
CURRENTLY OVER SOUTHERN CALIFORNIA WILL AFFECT OUR PRECIPITATION
CHANCES FOR THE NEXT DAY OR SO. ISOLATED CONVECTION WILL ATTEMPT
TO DEVELOP ACROSS EASTERN NEW MEXICO INTO THE SOUTH PLAINS LATER
THIS AFTERNOON. HOWEVER...STOUT HEIGHT RISES ALOFT GIVING RISE TO
SUBSIDENCE WILL ATTEMPT TO SUPPRESS ANY CONVECTION THAT TRIES TO
DEVELOP. WE WILL THEN TURN TO MORE WIDESPREAD RAIN CHANCES ON
SUNDAY.

STRONG ISENTROPIC UPGLIDE WILL DEVELOP OVER WEST TEXAS TONIGHT AND
CONTINUE THROUGH THE DAY ON SUNDAY AS THE UPPER LEVEL SYSTEM
MIGRATES EASTWARD ACROSS THE SOUTHWESTERN US. THIS WILL ALSO
COINCIDE WITH WEAK Q-VECTOR CONVERGENCE ALOFT. ALTHOUGH THIS
CLOSED UPPER LOW WILL RAPIDLY WEAKEN AND OPEN UP AS IT EJECTS OUT
OF ARIZONA ENOUGH LIFT WILL BE AVAILABLE FOR RAIN SHOWERS AREA
WIDE ON SUNDAY. INSTABILITY WILL BE VERY LIMITED WITH WEAK MID
LEVEL LAPSE RATES OVERHEAD. ALTHOUGH THE PREDOMINANT PRECIPITATION
WILL BE LIGHT RAIN...NON-ZERO CHANCES EXIST OF A RUMBLE OF THUNDER
OR TWO. WE WILL SEE A REINFORCING SHOT OF SURFACE RIDGING TONIGHT
LEADING TO AN EXTENDED PERIOD OF COOL EASTERLY UPSLOPE FLOW.
THESE SURFACE CONDITIONS COMBINED WITH CLOUD COVER ON SUNDAY WILL
LEAD TO A VERY COOL DAY WITH AFTERNOON TEMPERATURES ONLY IN THE
50S AND 60S.

LONG TERM...
BIGGEST QUESTION FOR THE END OF THE WEEKEND IS WHEN PRECIPITATION
WILL START TO TAPER OFF. EASTERLY UPSLOPE FLOW WILL PERSIST INTO
MONDAY MORNING BUT ISENTROPIC LIFT WILL BE ON THE DECREASE AT THE
SAME TIME. UPPER LEVEL JET STREAK WILL BE MOVING EAST AND WE
SHOULD FINALLY BE OUT FROM UNDER THE RIGHT ENTRANCE REGION
SOMETIME IN THE MORNING WHICH WILL REDUCE THE AMOUNT OF SYNOPTIC
LIFT AVAILABLE. DID TAPER POPS BACK FOR MONDAY MORNING AND
COMPLETELY REMOVE BY MONDAY AFTERNOON WHILE ALSO REDUCING THE
AMOUNT OF CLOUD COVER LATER IN THE DAY. TEMPERATURES WILL STILL BE
BELOW NORMAL AS THE SURFACE RIDGE WILL REMAIN OVER THE REGION
THROUGH MONDAY AFTERNOON.

RIDGING WILL START TO INCREASE OVER THE SOUTHERN ROCKIES INTO
NORTHERN MEXICO TUESDAY WHICH WILL PLACE INCREASING NORTHWESTERLY
FLOW OVER THE AREA. THE NAM AND ECMWF ARE STILL PRETTY BULLISH ON
DEVELOPING NORTHWEST FLOW THUNDERSTORMS AND MOVING THE COMPLEX
INTO THE FORECAST AREA AFTER SUNSET BUT THE NAM SOLUTION APPEARS
TO BE DUE TO SOME CONVECTIVE FEEDBACK AND THE ECMWF IS GENERATING
PRECIPITATION ALONG A PRETTY STRONG FRONTAL BOUNDARY THAT THE GFS
AND CANADIAN DOES NOT SHOW. WILL KEEP THE FORECAST DRY FOR NOW AS
THE DIFFERENCES ARE PRETTY SIGNIFICANT AND APPEAR TO BE DUE TO THE
GFS AND NAM DEEPENING/STRENGTHENING THE DEPARTING TROUGH OVER THE
CENTRAL U.S. MODELS DO AGREE THAT THE RIDGE SHOULD BE OVER THE
AREA ON THURSDAY WITH SUBTLE DIFFERENCES ON HOW FAR EAST BEYOND
THAT. TEMPERATURES WILL WARM BACK UP TO NORMAL OR SLIGHTLY ABOVE
NORMAL THROUGH THE END OF NEXT WEEK BEFORE WE SEE A RETURN OF THE
DRYLINE AND POSSIBLY RAIN CHANCES ONCE AGAIN. END OF NEXT WEEK
INTO NEXT WEEKEND MAY BE A BIT MORE ACTIVE AS BOTH THE GFS/ECMWF
SHOW THE DRYLINE SHAPING UP WITH STRONG SOUTHWESTERLY FLOW OVER
THE AREA. DID INTRODUCE POPS FOR FRIDAY NIGHT INTO EARLY SATURDAY
MORNING BUT KEPT POPS BELOW MENTION FOR SATURDAY NIGHT INTO SUNDAY
DUE TO UNCERTAINTIES IN DRYLINE POSITION...CAP STRENGTH...AND
STRENGTH OF A POSSIBLE CLOSED LOW OR TROUGH OVER THE INTERMOUNTAIN
WEST.

JORDAN

&&

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

$$

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