Severe Thunderstorm Warning 129, NWS Lubbock, TX

SOUTH PLAINS AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
330 PM CDT SUN JUN 9 2002

...UPDATED...

THE LATEST RUN OF THE MESO ETA MODEL SHOWS THAT THE HIGH BASED
CONVECTION DEVELOPING IN EASTERN NM WILL MOVE EAST INTO DEEPER
MOISTURE AND EXPAND IN AREAL COVERAGE AND INTENSITY. CAPES OVER THE
CENTRAL COUNTIES ARE BETWEEN 3000 AND 4000 J/KG AND THE
STRENGTHENING LLJ WILL AID IN THE DEVELOPMENT OF A CONVECTIVE
COMPLEX OF STORMS...MAY BE SIMILAR TO THE EVENT OF LAST EVENING.
THOUGH MID-LEVEL WINDS LOOK WEAKER. HEAVIEST RAINS WILL PROBABLY
OCCUR OVER THE NORTHWEST AND NORTH CENTRAL COUNTIES DURING THE
EVENING HOURS. I WILL PLACE 50 POPS IN THE NORTHWEST ZONES...30 POPS
CENTRAL AND 20 POPS EAST ZONES DURING THE FIRST PERIOD.

...........PREVIOUS DISCUSSION....................

THE 12Z UPPER AIR ANALYSIS SHOWED AN INTENSE UPPER LEVEL LOW OVER
THE NORTHERN GREAT BASIN WITH A DOWN STREAM UPPER LEVEL RIDGE OVER
THE EASTERN 2/3 OF THE CONUS. THE 17Z SFC MAP SHOWED A LEE SFC
TROUGH AXIS/SFC DRYLINE EXTENDING FROM EASTERN CO SOUTH-SOUTHWEST
INTO EASTERN NM. DEEP GULF MOISTURE WAS LOCATED EAST OF THE TROUGH
AXIS...WITH 70 DEGREE DEW POINT AT LBB.

DURING THE AFTERNOON HOURS THE SFC DRYLINE SHOULD MIX EAST TO THE NM
AND TX STATE BORDER...POSSIBLY INTO THE WESTERN COUNTIES OF THE
CWFA. AT 17Z SURFACE TEMPERATURES OVER SOUTHEAST NM WERE ALREADY IN
THE LOWER 90S WITH VERY LITTLE CU DEVELOPING AHEAD OF SFC DRYLINE.
THE CAP MAY BE A BIT STRONGER THAN WHAT THE 12 HOUR MESO ETA FCST
SND SHOWED. ISOLATED THUNDERSTORM MAY DEVELOP AHEAD OF THE DRYLINE
OVER THE WESTERN COUNTIES OF THE CWFA...AS MAX TEMPS APPROACH
CONVECTIVE TEMPS...AND WEAK SFC CONVERGENCE LIFTS BOUNDARY LAYER
PARCELS TO THEIR LFCS. ALONG THE DRYLINE DEWPOINTS WILL PROBABLY
MIX OUT A BIT INTO THE UPPER 50S...THUS STORMS SHOULD BE HIGH BASED
GIVEN 40 DEG DEW POINT DEPRESSIONS. THE ISOLATED STORMS MAY MOVE
EAST INTO THE CENTRAL COUNTIES OF THE CWFA THIS EVENING...THAT IS IF
THEY DO FORM. THE CAP SHOULD INHIBIT STORMS FROM DEVELOPING OVER THE
EASTERN COUNTIES OF THE CWFA. ANY ISOLATED STORMS SHOULD DISSIPATE
AFTER SUNSET.

THE H5 UPPER LOW OVER THE NORTHERN GREAT BASIN WILL LIFT NORTHEAST
INTO SOUTHERN CANADA DURING THE NEXT 60 HOURS. AN H5 RIDGE AXIS WILL
HOLD OVER TX AND EXTEND NORTHEAST INTO THE GREAT LAKE STATES. THE
850MB FLOW WILL VEER TOMORROW ACROSS CWFA WHICH WILL CAUSE THE
DEEPEST GULF MOISTURE TO BE ADVECTED EAST OF THE CWFA. A DIFFUSE SFC
DRYLINE MAY BE LOCATED OVER THE EASTERN COUNTIES THE NEXT TWO
DAYS...BUT THE CAP LOOKS TOO STRONG FOR ANY STORMS TO FORM.
AFTERNOON HIGH TEMPERATURES WILL WARM INTO THE MID 90S TO AROUND 100
DEGREES ACROSS THE CWFA THROUGH WEDNESDAY.

THE LONGER RANGE MODELS ALL SHOW AN H5 LONG WAVE TROUGH DEVELOPING
OVER THE THE EASTERN CONUS WITH AN H5 RIDGE OVER THE WESTERN CONUS.
THIS WILL CAUSE A COLD FRONT TO MOVE SOUTH ACROSS THE CENTRAL PLAINS
ON THURSDAY.  IM NOT REALLY SURE ON THE EXACT TIMING OF THE NEXT
FROPA OR HOW MUCH COOLER THE AIR MASS WILL BE BEHIND THE FRONT...BUT
THE AVN SHOWS THE FRONT MOVING SOUTH ACROSS WEST TX ON THU AND
BECOMING STATIONARY JUST SOUTH OF THE AREA ON FRIDAY. UPSLOPE FLOW
MAY DEVELOP NORTH OF THE FRONT WHICH WILL ADVECT DEEPER MOISTURE
NORTHWEST ONTO THE HIGHER TERRAIN OF NM. WITH NORTHWEST FLOW ALOFT
DEVELOPING OVER WEST TEXAS...ANY CONVECTION THAT DOES DEVELOP ON THE
HIGHER TERRAIN OF NM ON THU AND FRI MAY MOVE SOUTHEAST ACROSS THE
CWFA DURING THE EVENING AND NIGHTIME HOURS. THE AVN PATTERN LOOKS
CONDUCIVE FOR LATE EVENING MCSS MOVING ACROSS THE AREA ON THURSDAY
AND FRIDAY NIGHT.  ATTM I WILL LEAVE THE SLIGHT CHANCE OF RAIN IN
FOR THURSDAY AND FRIDAY DUE TO THE UNCERTAINTY IN TO THE DEGREE OF
UPSLOPE FLOW NORTH OF THE FRONT. BY EARLY NEXT WEEK THE WESTERN H5
RIDGE AXIS WILL MOVE EAST TOWARDS WEST TEXAS CAUSING DRY CONDITIONS
AND AFTERNOON HIGHS TO WARM BACK INTO THE 90S MAY BE NEAR 100
DEGREES BY EARLY NEXT WEEK.

FRIONA      64/ 96/ 65/ 97/ 63 2000
TULIA       65/ 97/ 66/ 98/ 64 1000
LUBBOCK     68/ 97/ 68/ 99/ 66 1000
BROWNFIELD  68/ 97/ 68/ 98/ 67 1000
CHILDRESS   70/ 99/ 71/101/ 72 -0-0
ASPERMONT   72/ 98/ 73/100/ 73 -0-0

.LUB...NONE

20

TXZ021>024-027>030-033>035-039>041-100300-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE LUBBOCK TX
629 PM CDT SUN JUN 9 2002

A SEVERE THUNDERSTORM WATCH IS IN EFFECT UNTIL 10 PM FOR THE
FOLLOWING COUNTIES...

BAILEY...BRISCOE...CASTRO...COCHRAN...FLOYD...HALE...HOCKLEY...
LAMB...LUBBOCK...LYNN...PARMER...SWISHER...TERRY...AND YOAKUM.

A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE FAVORABLE FOR SEVERE
THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. PERSONS IN THESE AREAS
SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER CONDITIONS AND
LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS.  SEVERE
THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES.