Severe Thunderstorm Warning 137, NWS Lubbock, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
646 PM CDT THU JUN 4 2009

.UPDATE...
UPDATED ZONES TO INCLUDE SVR THUNDERSTORM WATCH 331 VALID UNTIL 05Z.
COMPLEX OF STRONG TO SVR TSRA MAKING ITS WAY ACROSS THE SWRN TX
PANHANDLE. THIS ACTIVITY HAS BEEN MOVING IN A SERLY DIRECTION BUT
IS EXPECTED TO PROPAGATE IN A MORE SRLY DIRECTION ALONG AND EAST
OF THETA-E AXIS ALONG TX/NM BORDER. LARGE HAIL AND DAMAGING WINDS
WILL BE THE PRIMARY THREAT. 26

&&

.AVIATION...
PRIMARY CONCERN FOR THIS CYCLE WILL BE CONVECTIVE CHANCES
PARTICULARLY AT KLBB. COMPLEX OF STRONG TO SEVERE THUNDERSTORMS
NOW MAKING ITS WAY ACROSS THE TX PANHANDLE. THESE STORMS COULD
GENERATE GUSTY OUTFLOW BOUNDARIES TEMPORARILY INCREASING LLWS
THREAT.  HAIL WILL BE POSSIBLE WITH THE STRONGER STORMS. 26

&&

.PREV DISCUSSION... /ISSUED 321 PM CDT THU JUN 4 2009/

SHORT TERM...
FEW POP/WX GRID ADJUSTMENTS WERE MADE. ATTENTION REMAINS FOCUSED ON
LATE DAY AND NIGHTTIME RAIN/STORM CHANCES.

CURRENT RADAR/SATELLITE TRENDS SHOW INCREASING CONVECTION OVER THE
HIGHER TERRAIN OF NEW MEXICO...AS WELL AS AN INCREASING CU FIELD
VICINITY A WEAK CONVERGENCE ZONE OVER THE WESTERN PANHANDLE. MODELS
CONTINUE TO SUGGEST THAT CONVECTION WILL ADDITIONALLY INITIATE
WITHIN THE PANHANDLE CONVERGENCE/CU FIELD IN THE NEXT 2-4 HOURS...
AND THUS WILL MAINTAIN THE RECENTLY INTRODUCED SLIGHT CHANCE/CHANCE
20 TO 30 PERCENT POPS OVER THE NORTHWEST/NORTH-CENTRAL ZONES DURING
THE 21-00Z TIMEFRAME. OTHERWISE...AN INSTABILITY AXIS OF AROUND 2000
J/KG EXIST ALONG AND JUST WEST OF THE TEXAS NEW MEXICO BORDER...ON
THE WESTERN PERIPHERY OF THE CURRENT SURFACE RIDGE. LIKEWISE...
RATHER IMPRESSIVE DEEP LAYER SHEAR IS JUXTAPOSED OVER THE SAME
AREA...WITH 0-6KM SHEAR AOA 30-40KT EAST OF THE SHARP ROCKIES UA
RIDGE AXIS. THUS CONVECTION...EITHER INITIATING OVER THE WESTERN
PANHANDLE OR PROPAGATING SOUTHEASTWARD OVER THE NEW MEXICO PLAINS...
WILL HAVE AN OPPORTUNITY TO BECOME ORGANIZED/SEVERE. GIVEN SOME
POTENTIAL FOR HIGH-BASED SUPERCELL STORM STRUCTURES THROUGH EARLY
EVENING...LARGE HAIL AND DAMAGING WINDS APPEAR POSSIBLE AS STORMS
APPROACH THE NORTHWESTERN ZONES LATE THIS AFTERNOON AND INTO THIS
EVENING. GIVEN THE HIGH-BASED NATURE OF THE STORMS...COLD POOLS MAY
EVENTUALLY FAVOR A TRANSITION TOWARD ONE OR MORE CONVECTIVE CLUSTERS
LATER IN THE EVENING. ALSO...A NOTABLE 30+KT LLJ IS PROGGED...AND
WILL LIKELY PROMOTE/SUSTAIN AT LEAST ISOLATED STORMS ROLLING
SOUTHEASTWARD THROUGH MUCH OF THE NIGHT. THUS CONFIDENCE REMAINS
THAT SCATTERED THUNDERSTORMS WILL IMPACT THE NORTHWESTERN HALF OF
THE SOUTH PLAINS...MOST LIKELY BETWEEN 00-06Z.

THE UA RIDGE AXIS IS PROGGED TO TRANSLATE EAST OF WEST TEXAS
FRIDAY...WITH INCREASING SOUTHWESTERLY FLOW ALOFT AND A TIGHTENING
SURFACE TROUGH OVER THE AREA. THIS CONTINUES TO ARGUE FOR STORM
CHANCES OVER THE WESTERN/CENTRAL SOUTH PLAINS AS MODELS PROG
CONVECTIVE QPF ALONG/EAST OF THIS FEATURE. WITH INCREASED SOUTHERLY
FLOW AND LOW LEVEL THERMAL RIDGING...DAYTIME TEMPERATURES WILL ALSO
WARM TO ABOVE SEASONAL AVERAGES.

LONG TERM...
WEAKER CHANCES OF PRECIPITATION ALONG A DRYLINE WILL CAP OFF THE
WEEK THROUGH THE WEEKEND. ON SATURDAY...MID AND UPPER LEVEL FLOW
WILL BECOME VEERED WHICH WILL FORCE THE DRYLINE FURTHER EAST OFF THE
CAPROCK. THE HIGHEST INSTABILITY WILL ALSO BE OFF THE CAPROCK WITH
0-6KM FLOW STILL RELATIVELY WEAK ACROSS THE AREA. A RIDGE OF HIGH
THETA-E AIR WILL ALSO BE EAST OF THE AREA WITH THE ATMOSPHERE WEAKLY
CAPPED OVER WEST TEXAS. THEREFORE HIGH BASED ISOLATED STORMS ARE NOT
OUT OF THE QUESTION FOR SATURDAY AFTERNOON AND EVENING DESPITE A
LACK OF AN UPPER LEVEL DISTURBANCE NEAR THE AREA.

THE CLOSED UPPER LOW OFF THE WESTERN US COAST WILL BEGIN TO MOVE
THROUGH THE FLOW ACROSS THE CENTRAL ROCKIES EARLY THIS WEEKEND. FLOW
WILL BECOME INCREASINGLY VEERED ON SUNDAY WHICH IS EXPECTED TO PUSH
MOISTURE EVEN FURTHER EAST...POSSIBLY HAVING THE DRYLINE COMPLETELY
EAST OF THE FA. HOWEVER...THE NAM AND EURO MODEL RUNS HAVE A PIECE
OF ENERGY MOVING SLOWER AND FURTHER SOUTH THAN INDICATED BY THE
LATEST GFS SOLUTION. THE FORMER MODEL SOLUTIONS WOULD MAKE
PRECIPITATION CHANCES SLIGHTLY MORE LIKELY ON SUNDAY AFTERNOON AND
EVENING BUT HAVE KEPT POPS BELOW MENTION FOR THE MOMENT. BEYOND THE
WEEKEND...HEIGHTS WILL CONTINUE TO BUILD FROM THE SOUTH AS ANOTHER
TROUGH ENTERS THE WESTERN US. A POSSIBLE COLD FRONT EARLY NEXT WEEK
IS CONTINUING TO BE TROUBLESOME FOR THE FORECAST. HAVE CONTINUED TO
SIDE WITH A TUESDAY FRONTAL PASSAGE AS SHOWN IN THE GFS HOWEVER THE
FRONT COULD LINGER AS A STATIONARY FRONT NEAR THE AREA THROUGH MID
WEEK. HAVE ALSO NOT INCLUDED ANY POPS YET WITH THIS FRONTAL PASSAGE
DUE TO THE MODEL INCONSISTENCIES. JDV

&&

.PRELIMINARY POINT TEMPS/POPS...
FRIONA        56  92  60  94  59 /  40  30  10  10  10
TULIA         57  92  65  94  63 /  40  30  20  10  10
PLAINVIEW     58  92  64  94  64 /  30  30  20  10  10
LEVELLAND     59  96  65  97  65 /  30  30  20  10  10
LUBBOCK       61  95  67  97  68 /  30  30  20  10  10
DENVER CITY   59  97  64  97  64 /  20  20  20  10  10
BROWNFIELD    59  97  66  97  66 /  20  30  20  10  10
CHILDRESS     58  93  69  98  72 /  20  10  20  20  20
SPUR          57  93  68  98  70 /  20  20  20  20  20
ASPERMONT     56  96  71 100  72 /  20  10  20  20  20

&&

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

26/33/26

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