Area Forecast Discussion
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FXUS64 KLUB 231713
AFDLUB
AFDLUB

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LUBBOCK TX
1213 PM CDT SAT MAY 23 2015

.UPDATE...
AS DISCUSSED IN THE PREVIOUS UPDATE...WE HAVE GONE AHEAD AND
TRIMMED OUR FLASH FLOOD WATCH TO POINTS ALONG AND EAST OF A
SILVERTON TO RALLS TO TAHOKA LINE. WHERE THE FLOOD WATCH IS STILL
IN EFFECT IT WAS EXTENDED IN TIME TO 9 PM THIS EVENING. FURTHER
WEST...ON THE CAPROCK...LOCALIZED HEAVY RAIN COULD STILL
OCCUR...BUT A WIDESPREAD FLOODING THREAT IS NOT ANTICIPATED. IN
ADDITION TO ADJUSTING THE FLOOD WATCH...WE DID ALSO ADD A SEVERE
MENTION TO THE GRIDS AREA-WIDE FOR THIS AFTERNOON AND EVENING. NO
OTHER ADJUSTMENTS WERE MADE ATTM.

&&

.PREV DISCUSSION... /ISSUED 1143 AM CDT SAT MAY 23 2015/

UPDATE...
PRIMARY FOCUS FOR WIDESPREAD MODERATE/HEAVY RAIN THIS MORNING HAS
BEEN NORTH OF A CONVECTIVELY REINFORCED BOUNDARY THE LIES IN OUR
FAR NORTHERN ZONES...WITH THE HEAVIEST RAIN FALLING JUST NORTH OF
THE CWA. ELSEWHERE ACTIVITY HAS BEEN ISOLATED TO WIDELY SCATTERED
AT BEST. WE HAVE TRIMMED POPS FOR ALL BUT THE NORTHERN ZONES
THROUGH 18Z. AFTER 18Z...IT STILL APPEARS CONVECTION MAY INCREASE
IN COVERAGE AND INTENSITY LOCALLY...FAVORING THE EASTERN HALF OR
SO OF THE CWA AS MOISTURE TRANSPORT AND CONVERGENCE ALONG WITH
UPPER SUPPORT BECOME MORE FOCUSED THERE. THESE FACTORS MAY KEEP
THE RISK OF HEAVY RAIN ACROSS AT LEAST THE EASTERN ZONES THROUGH
THIS AFTERNOON AND PERHAPS INTO TONIGHT. FURTHER WEST ON THE
CAPROCK...SOME SEMBLANCE OF A DRYLINE IS EXPECTED TO SHARPEN NEAR
THE TX/NM LINE. THE DRYLINE COULD BE A FOCUS FOR ISOLATED TO
WIDELY SCATTERED STORM DEVELOPMENT THIS AFTERNOON/EVENING...THOUGH
NWP IS MIXED ON IF AND HOW MUCH ACTIVITY WILL DEVELOP. WHATEVER
DOES DEVELOP TOO COULD PRODUCE HEAVY RAINFALL...BUT THE THREAT
SHOULD BE MORE LOCALIZED AND GIVEN THIS WE WILL LIKELY ALLOW THE
FLASH FLOOD WATCH TO EXPIRE AT 18Z FOR MOST SPOTS ON THE CAPROCK.
IN ADDITION...STRONG INSTABILITY AND SUFFICIENT SHEAR COULD
SUPPORT A FEW SEVERE STORMS THIS AFTERNOON AND EVENING. THE
GREATEST THREAT FOR MORE ISOLATED CONVECTION WILL LIKELY BE NEAR
THE SURFACE TROUGH/DRYLINE WHERE SOME HEATING IS OCCURRING
ALREADY...THOUGH SEVERE STORMS COULD OCCUR JUST ABOUT ANYWHERE IN
THE FA. THE ENVIRONMENT COULD SUPPORT ALL MODES OF SEVERE WEATHER
INCLUDING LARGE HAIL...DAMAGING WINDS AND ISOLATED TORNADOES.

PREV DISCUSSION... /ISSUED 659 AM CDT SAT MAY 23 2015/

AVIATION...
IFR CEILINGS CONTINUE TO PLAGUE KLBB/KPVW THIS MORNING WHILE KCDS
CONTINUES TO SEE PERIODS OF FOG AND LIFR CEILINGS. EXPECTING TO
SEE CONDITIONS GRADUALLY IMPROVE THIS MORNING WITH VFR CONDITIONS
ATTEMPTING TO MAKE A RETURN BY LATE THIS MORNING. OTHER ISSUE OF
CONCERN IS PROSPECTS FOR TSRA THROUGH THE PERIOD. AREA OF
THUNDERSTORMS NORTH OF ALL TERMINALS DOES NOT SHOW MUCH PROMISE
IN TERMS OF ADDITIONAL DEVELOPMENT SOUTH AT THIS TIME.
HOWEVER...HEATING LATE THIS MORNING INTO THIS AFTERNOON SHOULD
ALLOW FOR RENEWED THUNDERSTORM DEVELOPMENT LOCALLY...WITH BETTER
CHANCES FOR KCDS. HAVE THEREFORE INSERTED MENTION FROM 17-23Z AS A
SERIES OF UPPER DISTURBANCES MOVES THROUGH IN CONJUNCTION WITH
PLENTY OF DEEP LAYER MOISTURE. NOT AS CONFIDENT IN SEEING
CONVECTION AT KLBB OR KPVW...SO HAVE LEFT MENTION OUT FOR NOW.
WILL SEE WINDS BECOME BREEZY AT THESE TWO SITES...INCREASING TO
15-20 KNOTS WITH GUSTS APPROACHING 25-30 KNOTS. LOW CEILINGS MAY
RETURN LATER THIS EVENING INTO TONIGHT...WITH HIGHEST
PROBABILITIES AT KCDS.

PREV DISCUSSION... /ISSUED 417 AM CDT SAT MAY 23 2015/

SHORT TERM...
SHOWERS AND THUNDERSTORMS WILL CONTINUE FILLING IN ACROSS THE FAR
SOUTHWEST PANHANDLE AND SOUTH PLAINS EARLY THIS MORNING...BEFORE
SPREADING EAST OF THE CAPROCK ESCARPMENT AFTER DAYBREAK. THE MAIN
DRIVER OF THIS ACTIVITY REMAINS OVER FAR EASTERN ARIZONA INTO
WESTERN NEW MEXICO IN THE FORM OF AN UPPER VORTICITY MAXIMUM
DOWNSTREAM OF ITS PARENT UPPER LOW MOVING INTO NORTH-CENTRAL
ARIZONA. A WARM FRONTAL BOUNDARY WILL CONTINUE TO LIFT NORTH FROM
THE SOUTHERN SOUTH PLAINS AND ROLLING PLAINS INTO THE TEXAS
PANHANDLE THIS MORNING STREAMING IN 60 DEGREE DEWPOINTS ON MOIST
SOUTHEAST LOW LEVEL FLOW COURTESY OF A 30-40 KNOT LOW LEVEL JET. NOT
EXPECTING MUCH IF ANY SEVERE CONVECTION THIS MORNING GIVEN
WIDESPREAD DENSE FOG SUGGESTING A STOUT SURFACE-BASED INVERSION IN
PLACE.

COULD SEE A FEW STRONG ELEVATED CORES GIVEN DEEP LAYER SHEAR OF 40-
50 KNOTS...BUT THE BRUNT OF ANY SEVERE THREAT WILL BE FOCUSED ON
THIS AFTERNOON/EVENING AS INSTABILITY INCREASES WITH DIURNAL HEATING
AND COOLING MID-LEVEL TEMPERATURES ALOFT. LARGE HAIL WILL BE THE
PRIMARY THREAT...ALTHOUGH COULD SEE ENOUGH DRY AIR PUNCH IN FROM THE
WEST TO ALLOW FOR A FEW DOWNBURST WIND GUSTS AS A SURFACE LOW IN THE
FRONT RANGE NUDGES EASTWARD TOWARD THE HIGH PLAINS.

WHILE LOCALLY HEAVY RAINFALL MAY OCCUR IN ANY PARTICULAR LOCATION
THIS MORNING AND AFTERNOON...THE PRIMARY AREA OF CONCERN IN REGARD
TO WIDESPREAD FLOODING WILL BE ACROSS THE ROLLING PLAINS AND FAR
SOUTHEASTERN TEXAS PANHANDLE LATER THIS MORNING INTO THIS AFTERNOON.
FOLLOWING THIS MORNING/S SWATH OF STORMS...ANOTHER DISTURBANCE OR
TWO LOOK PRIMED TO MOVE THROUGH THE ROLLING PLAINS LATER ON TODAY AS
DEEP LAYER MOISTURE REMAINS LOCKED IN PLACE. WHILE TRAINING CELLS
THIS MORNING ARE NOT A HUGE CONCERN GIVEN STEADY EASTWARD PROGRESS
OF THE LEAD UPPER VORTICITY MAXIMUM...MAY SEE THIS THREAT INCREASE
AS MULTIPLE ROUNDS OF LIFT SPARK SOUTHWEST TO NORTHEAST PROPAGATING
STORMS. IF THIS MORNING/S ROUND OF STORMS PLAYS OUT AS
EXPECTED...WILL LIKELY BE ABLE TO TRIM THE FLASH FLOOD WATCH FOR
MUCH OF THE SOUTH PLAINS AND FAR SOUTHWEST PANHANDLE SHORTLY AFTER
DAYBREAK.

WHILE ACTIVITY SHOULD SLOWLY TRAVERSE EAST BY THIS EVENING AND
TONIGHT...ANOTHER UPPER IMPULSE MOVING OUT OF CHIHUAHUA WILL
ENCROACH UPON WEST TEXAS IN COMBINATION WITH THE RIGHT ENTRANCE
REGION OF A 100+ KNOT UPPER JET MAX. MID LEVEL WIND FIELDS DO SHOW A
WEAKNESS NEAR H70-50...SO WILL HAVE TO SEE HOW THIS AFFECTS CELL
ORGANIZATION. MUCH OF THE REGION WEST OF THE CAPROCK ESCARPMENT
SHOULD SEE ENOUGH OF A RECOVERY PERIOD...AFTER HIGH TEMPERATURES IN
THE MID 70S...TO PROVIDE ENOUGH INSTABILITY FOR AT LEAST SCATTERED
DEVELOPMENT LATER THIS EVENING INTO THE OVERNIGHT HOURS.


LONG TERM...
BASIC PREMISE OF FORECAST THINKING IN THE EXTENDED REMAINS QUITE
SIMILAR TO LAST NIGHT/S EXPECTATIONS. THE UPPER LOW TO OUR WEST
SHOULD WORK ITS WAY INTO SRN WY/NRN CO BY SUNDAY MORNING. A COUPLE
OF LOBES OF ENERGY WILL ROTATE ABOUT THIS LOW THE FIRST OF WHICH
WILL BE ORIENTED ALONG THE FRONT RANGE OF THE ROCKIES TO NEAR THE
SACRAMENTOS. THE SECOND AND MORE SIGNIFICANT TROUGH WILL EXIST
FROM THE PARENT LOW TO SRN CALIFORNIA. AS SUCH...WE WILL SEE
SYNOPTIC SCALE LIFT SUNDAY MORNING FOLLOWED BY ANOTHER ROUND ON
MONDAY MORNING AFTER WHICH FLOW ALOFT WILL BRIEFLY BECOME ZONAL.
EMBEDDED DISTURBANCES IN THE MEAN FLOW WILL PERSIST ON TUESDAY
BEFORE SOUTHWESTERLY FLOW ALOFT SETS IN FOR WEDNESDAY/THURSDAY AS
CORE OF NEXT DISTURBANCE TAKES AIM ON WRN KS.

RAIN SHOWERS AND PERHAPS SOME THUNDERSTORM ACTIVITY WILL BE ONGOING
BY SUNDAY MORNING ACROSS THE AREA THOUGH THE ECM/NAM SUGGEST THAT
IT WILL BE FURTHER EAST THAN DOES THE GFS. THIS IS QUITE LIKELY
DUE TO THE GFS KNOWN BIAS TOWARD OVER-ZEALOUS MOIST ADVECTION WITH
AN APPROACHING TROUGH. GUIDANCE DEPICTS THE DRYLINE MAKING AN
EASTWARD PUSH ON SUNDAY WITH VARYING DEGREES RANGING FROM THE
CENTRAL ZONES TO EAST OF OUR CWFA. GIVEN THE MOIST SOILS AM MUCH
MORE INCLINED TO BELIEVE THAT THE DRYLINE WILL REMAIN WELL WEST OF
OUR EASTERN BORDER. DEPENDING ON HOW WASHED-OUT THE ATMOSPHERE IS
FROM SUNDAY MORNING/S CONVECTION WE COULD SEE SOME STRONG ACTIVITY
ASSOCIATED WITH THE DRYLINE. THERE ARE SOME INCONSISTENCIES
EVIDENT IN NWP PRECIPITATION FIELDS INTO MONDAY WITH CONVECTION
OCCURRING IN THE SUBSIDENT PORTION OF THE TROUGH. HOWEVER...SOME
TSTM ACTIVITY DURING THE AFTERNOON IS CERTAINLY POSSIBLE IN OUR
EASTERN ZONES. RAIN CHANCES DIMINISH TUESDAY AND WEDNESDAY BEFORE
THE NEXT STORM SYSTEM ARRIVES THURSDAY AND FRIDAY. ALL IN ALL A
CHANGABLE/WET FORECAST WITH AT LEAST SOME POTENTIAL FOR RAINFALL
SOMEWHERE IN OUR CWFA EACH DAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
FRIONA        50  76  48  76 /  20  10  10  10
TULIA         54  76  50  74 /  30  20  10  20
PLAINVIEW     56  77  51  76 /  40  20  10  20
LEVELLAND     56  79  52  79 /  40  20  10  10
LUBBOCK       58  80  54  80 /  40  20  10  20
DENVER CITY   56  79  53  80 /  40  10  10  10
BROWNFIELD    57  79  53  81 /  40  10  10  20
CHILDRESS     60  79  57  80 /  50  40  10  20
SPUR          58  80  55  79 /  50  30  10  30
ASPERMONT     62  83  59  83 /  60  40  10  30

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 9 PM CDT THIS EVENING FOR TXZ024>026-
030>032-036>038-041>044.

&&

$$

23/33




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