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FXUS64 KLUB 050909
AFDLUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
409 AM CDT TUE MAY 5 2015

.SHORT TERM...
...POTENTIAL FOR ADDITIONAL HEAVY RAIN THIS MORNING AND SEVERE
WEATHER THIS AFTERNOON AND EVENING HIGHLIGHT THE SHORT TERM
FORECAST...

1. NEAR-TERM PERIOD. AT 3 AM...A LARGE SHIELD OF LIGHT TO MODERATE
RAIN...WITH EMBEDDED THUNDERSTORMS AND HEAVIER RAIN RATES STRETCHES
FROM EASTERN SWISHER TO KENT COUNTY...AND IS MOVING NEWD...ALTHOUGH
ADDITIONAL DEVELOP IS ONGOING ACROSS IT/S SRN FLANK. THIS PRECIP
SHIELD SHOULD MOSTLY EXIT THE AREA BY 5 AM OR SO...AND SHOULD
PRODUCE ADDITIONAL RAINFALL OF ABOUT 0.5 TO 1.5 INCHES ACROSS MUCH
OF THE ROLLING PLAINS...WHICH SHOULD NOT POSE MORE THAN A
LOCALIZED THREAT OF MINOR STREET...DITCH AND GULLY FLOODING.

2. REMAINDER OF THE MORNING...ROUGHLY 4 AM TO 11 AM OR SO. THE NEXT
ROUND OF SHOWERS AND THUNDERSTORM CURRENTLY DEVELOPING IN EASTERN
NEW MEXICO...AND FORCED BY THE NEXT SHORTWAVE/STRONGLY DIFFLUENT
REGION ROUNDING THE UPPER LOW OVER AZ AND NM...IS EXPECTED TO MOVE
NEWD ACROSS MUCH OF THE FORECAST AREA. THE SERLY LLJ WILL CONTINUE
TO PROVIDE A RICH MOISTURE FEED INTO THIS NEXT COMPLEX. THE MAIN
CONCERN WITH THIS ROUND OF STORMS WILL BE THE POTENTIAL FOR
MODERATE TO HEAVY RAIN TO FALL ACROSS AREAS ALREADY INUNDATED BY
HEAVY RAINFALL MONDAY EVENING. OUR CURRENT FLASH FLOOD WATCH GOES
THROUGH 7 AM/12 UTC...AND WE WILL MAINTAIN THE WATCH UNTIL THE
BULK OF THE NEW ACTIVITY MOVES ACROSS THE STATE LINE AND WE CAN
REASSESS THE FLOODING POTENTIAL. THE WATCH MAY NEED TO BE
EXTENDED.

3. THIS AFTERNOON AND EVENING. THIS PORTION OF THE FORECAST WILL BE
HIGHLY DEPENDENT ON WHAT HAPPENS THIS MORNING. THE MAJORITY OF THE
GUIDANCE CLEARS THE SECOND COMPLEX THROUGH MOST OF THE FORECAST AREA
BY MIDDAY...WHICH ALLOWS THE AIRMASS TO RECOVER AND DESTABILIZE
ACROSS MOST OF THE CWA THIS AFTERNOON. SHORT-RANGE GUIDANCE ALSO
SUGGESTS A DRYLINE WILL DEVELOP AND MOVE INTO THE CENTRAL SOUTH
PLAINS BY PEAK HEATING. EVEN THOUGH THE MOISTURE GRADIENT SHOULD NOT
BE VERY STRONG ALONG THE DRYLINE...CONVERGENT FLOW ALONG THE NORTH-
SOUTH AXIS OF INSTABILITY MAY MAKE IT A PREFERENTIAL BOUNDARY FOR
CONVECTIVE DEVELOPMENT. WE WILL ALSO HAVE TO WATCH FOR OTHER OUTFLOW
BOUNDARIES AND POSSIBLY A REMNANT MCV AS ADDITIONAL POTENTIAL CI
FOCI. ANY STORMS THAT DEVELOP WILL BE ABLE TO TAP INTO AN
ENVIRONMENT OF STEEP MID-LEVEL LAPSE RATES RESULTING IN HIGH
CAPE...AND STRONG WIND SHEAR...THAT CAN SUPPORT ROBUST...ROTATING
UPDRAFTS. IN ADDITION...FORECAST 0-1 KM HELICITY AND LOW LCL/S
SUGGEST THE POSSIBILITY FOR A TORNADO THREAT WITH ANY DISCRETE
SUPERCELLS...PARTICULARLY IF THEY INTERACT WITH A BOUNDARY. HEAVY
RAIN WILL CONTINUE TO BE A THREAT...ESPECIALLY IF THE ACTIVITY GROWS
UPSCALE IN THE EVENING HOURS.  QUESTIONS REGARDING SURFACE HEATING
AND POSSIBLE RAIN-COOLED OUTFLOW AND/OR SUBSIDENCE IN THE WAKE OF A
WELL-DEVELOPED MORNING MCS LOWER THE OVERALL CONFIDENCE IN THE
FORECAST AT THIS TIME.

ONGOING T-STORM ACTIVITY SHOULD GENERALLY PROGRESS TO THE E-NE THIS
EVENING AS THE UPPER TROUGH PIVOTS NEWD ACROSS NW TX INTO THE SRN
HIGH PLAINS.

.LONG TERM...
THE ACTIVE WEATHER PATTERN IS GOING TO CONTINUE ON THROUGH THE
REMAINDER OF THE WEEK AND PERHAPS INTO THE WEEKEND.

THE CURRENT WESTERN TROUGH WILL BE LIFTING THROUGH THE CENTRAL
PLAINS ON WEDNESDAY...BUT IT WILL QUICKLY BE REPLACED BY ANOTHER
UPPER LOW DROPPING INTO THE DESERT SOUTHWEST. THIS WILL KEEP
UNSETTLED SOUTHWEST FLOW ALOFT IN PLACE OVER WEST TEXAS. ALTHOUGH
TIMING ANY MINOR DISTURBANCES WITHIN THE FLOW IS DIFFICULT TO
IMPOSSIBLE AS WE GO FURTHER OUT IT TIME...THEY WILL UNDOUBTEDLY
OCCASIONALLY HELP STORM CHANCES AS A DRYLINE ROAMS THE SOUTH PLAINS
REGION.

THERE IS A CHANCE CONVECTIVE ACTIVITY MAY BE SOMEWHAT SUBDUED BEHIND
THE DEPARTING STORM SYSTEM ON WEDNESDAY. HOWEVER...BY PEAK
HEATING...STRONG INSTABILITY AND MINIMAL INHIBITION ARE PROGGED TO
BE IN PLACE EAST OF THE DRYLINE /WHICH WILL LIKELY BE BISECTING THE
CWA FROM NE TO SW/ AND MOST NWP DOES SUPPORT SCATTERED CONVECTION BY
LATE IN THE DAY. ADDITIONAL ROUNDS OF THUNDERSTORMS ARE THEN
SUPPORTED IN THIS PATTERN AS THE DRYLINE RESIDES SOMEWHERE IN THE
AREA AGAIN ON THURSDAY AND FRIDAY. DEPENDING ON THE TIMING OF ANY
UPPER SUPPORT...CONVECTION COULD PERSIST THROUGH THE OVERNIGHT HOURS
AT TIMES. EVENTUALLY...ON SATURDAY...THE SOUTHWESTERN LOW IS
PROGGED TO BEGIN TO LIFT NORTHEAST THROUGH THE INTERMOUNTAIN WEST.
THIS COULD HELP PULL THE DRYLINE EASTWARD...THOUGH IT MAY STILL
HANG UP IN OUR EASTERN ZONES BY LATE AFTERNOON AND PROVIDE A FOCUS
FOR MORE AFTERNOON AND EVENING STORM DEVELOPMENT ON SATURDAY.

THE UPPER LOW IS THEN FORECAST TO MOVE ACROSS THE CENTRAL OR
NORTHERN HIGH PLAINS ON SUNDAY...WITH A TROUGH AXIS HANGING BACK
INTO THE DESERT SOUTHWEST. MUCH OF THE AREA MAY BE IN THE DRY AIR
WEST OF THE DRYLINE...BUT AT LEAST THE SOUTHEAST ZONES COULD SEE
STORM CHANCES CONTINUE AS THE DRYLINE WILL LIKELY RESIDE SOMEWHERE
NEARBY SUNDAY AFTERNOON. A COLD FRONT SHOULD FINALLY MOVE THROUGH
THE FA EARLY MONDAY IN THE WAKE OF THE PASSING UPPER LOW AND THIS
WILL PROVIDE AT LEAST A BRIEF REPRIEVE FROM THE ACTIVE WEATHER
EARLY NEXT WEEK. BEFORE THEN...MODERATE TO STRONG INSTABILITY AND
MODEST DEEP LAYER SHEAR SHOULD BE PRESENT ALONG AND EAST OF THE
DRYLINE JUST ABOUT ANY DAY THROUGH THE REMAINDER OF THE WEEK AND
INTO THIS WEEKEND...SO SEVERAL ROUNDS OF SEVERE WEATHER ARE A
DISTINCT LIKELIHOOD OVER THE COMING DAYS. IT IS DEFINITELY
LOOKING LIKE A CLASSIC /PRE-DROUGHT/ MULTI-DAY STRETCH OF ACTIVE
MAY WEATHER. TEMPERATURES SHOULD BE SEASONABLY WARM THROUGH MUCH
OF THE LONG TERM...WITH A SLIGHT COOL DOWN BEHIND THE COLD FRONT
EARLY NEXT WEEK.

&&

.PRELIMINARY POINT TEMPS/POPS...
FRIONA        70  50  78  51 /  80  30  10  10
TULIA         68  54  79  56 /  90  60  10  20
PLAINVIEW     69  55  80  57 /  80  50  10  20
LEVELLAND     73  56  81  58 /  70  20  10  20
LUBBOCK       72  58  81  60 /  70  30  10  30
DENVER CITY   76  55  81  58 /  50  20  10  30
BROWNFIELD    75  57  81  59 /  60  20  10  30
CHILDRESS     71  61  83  63 /  80  70  30  40
SPUR          70  60  82  60 /  80  60  30  40
ASPERMONT     73  63  83  64 /  70  40  30  40

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 7 AM CDT THIS MORNING FOR TXZ021>024-
027>030-033>036-039>042.

&&

$$

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