National Weather Service Raw Text Product

215 
FXUS65 KVEF 170417
AFDLAS

MOJAVE DESERT/SOUTHERN GREAT BASIN AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
915 PM PDT TUE JUL 16 2002

.SYNOPSIS...RELATIVELY MOIST AND UNSTABLE AIR WILL REMAIN OVER THE 
MOJAVE DESERT AND SOUTHERN GREAT BASIN THROUGH WEDNESDAY... 
SUPPORTING THE DEVELOPMENT OF ISOLATED THUNDERSTORMS. A DRY 
SOUTHWEST FLOW ALOFT WILL THEN BEGIN TO DEVELOP THURSDAY AND FRIDAY 
AND WILL ELIMINATE THE CHANCE FOR PRECIPITATION BY THE END OF THE 
WEEK.  

.DISCUSSION...INTERACTIONS FROM OUTFLOW BOUNDARIES CONTINUE TO 
INITIATE THUNDERSTORM DEVELOPMENT THIS EVENING...PRIMARILY OVER 
LINCOLN AND SOUTHEAST SAN BERNARDINO COUNTIES. DESERT ROCK SOUNDING 
SHOWS A DROP IN TOTAL PRECIPITABLE WATER FROM YESTERDAY AND A STABLE 
LAYER AROUND 600 MB. THIS MATCHES WITH SATELLITE WHICH INDICATED 
CONVECTION BEING INHIBITED OVER SOUTHERN NYE AND WESTERN CLARK 
COUNTIES TODAY WITH DRYING NOTED ON WATER VAPOR IMAGES. STORMS TODAY 
WERE PULSE TYPE WITH WEAK SHEAR ENVIRONMENT IN PLACE. CONVECTION 
NOT AS WIDESPREAD AS I WOULD HAVE THOUGHT...PRIMARILY DUE TO THE 
REDUCTION IN OVERALL MOISTURE AND CAPPING INVERSION. WILL UPDATE TO 
ACCOUNT FOR CURRENT THUNDERSTORM TRENDS...WITH THE IDEA THAT 
THUNDERSTORMS WILL BE ENDING SOON ALL AREAS. UPDATES OUT SOON.

ON WEDNESDAY...SHORT WAVE NOW APPROACHING CA COAST STRENGTHENS AND 
SHARPENS AS MODERATE JET ROUNDS BASE OF TROUGH. PREFER SLIGHTLY 
STRONGER LOOKING AVN DEPICTION OF THIS FEATURE WITH 00Z ETA NOW 
BEGINNING TO CATCH UP TO THIS IDEA. BEST FORCING STILL LOOKS TO BE 
ACROSS THE SIERRA INTO SOUTH CENTRAL NEVADA ZONES. IN FACT UPWARD 
FORCING ACTUALLY PEAKS OUT IN THIS AREA BETWEEN 00Z AND 06Z 
THURSDAY...INDICATING THAT THUNDERSTORMS MAY CONTINUE WELL INTO THE 
LATE NIGHT THERE. STILL A LITTLE CONCERNED THAT EXIT REGION OF JET 
WILL PROVIDE SOUTHERN NEVADA WITH UPPER DIVERGENCE AND INCREASED 
SPEED SHEAR WHICH WILL ENHANCE AND SUSTAIN STORM DEVELOPMENT. 
MOISTURE PROFILES DO NOT CHANGE THAT MUCH AND THAT MAY BE THE 
LIMITING FACTOR. AT ANY RATE...WILL NOT MAKE ANY CHANGES SINCE 
EXISTING FORECAST IS ON TRACK WITH THE HIGHER THUNDERSTORM CHANCES 
ACROSS THE NORTH AND HIGHER TERRAIN IN THE SOUTH. GRADUAL DRYING TO 
OCCUR THURSDAY INTO FRIDAY AS SOUTHWEST FLOW ALOFT BEGINS TO PUSH 
DEEPER MOISTURE EAST. ENOUGH MOISTURE REMAINS IN WESTERN AZ TO  
SUPPORT SOME CONVECTION THROUGH THURSDAY WITH GUIDANCE CONSISTENT IN 
DEVELOPING A FEW DRY DAYS AFTER THAT. THIS WILL NOT LAST LONG AS MRF 
SUGGESTING THE SUBTROPICAL RIDGE WILL BECOME RE-ESTABLISHED NEAR THE 
FOUR CORNERS AREA BY SUNDAY OR MONDAY RESULTING IN A RETURN TO FLOW 
OF MOISTURE AND AT LEAST LOW GRADE MONSOON CONDITIONS AT THAT TIME.

NEMETH 

.LAS...NONE.