AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
1016 AM PDT FRI JUL 3 2009

.SYNOPSIS...SCATTERED THUNDERSTORMS WILL BE SEEN ONCE AGAIN ACROSS
SOUTHERN NEVADA AND NORTHWEST ARIZONA TODAY BEFORE DRIER CONDITIONS
MOVE INTO THE AREA ON SATURDAY AND SUNDAY. THE DRIER CONDITIONS WILL
THEN CONTINUE INTO THE MIDDLE OF NEXT WEEK. TEMPERATURES WILL BE
NEAR TO SLIGHTLY ABOVE NORMAL THROUGH THE HOLIDAY WEEKEND.
&&

.UPDATE...WATER VAPOR SHOWS DRIER AIR HAS SLID EASTWARD INTO THE
MOJAVE DESERT AND SOUTHERN GREAT BASIN OVERNIGHT. BASED ON SOUNDINGS
AND GOES SENSORS THE 1 INCH PWAT LINE WAS PROBABLY EXTENDING FROM
THE NYE-LINCOLN BORDER SOUTH TO CENTRAL SAN BERNARDINO COUNTY.
UNLIKE YESTERDAY WHEN THERE WERE A FEW DISTURBANCES AROUND TO
TRIGGER ACTIVITY AND A MOISTURE GRADIENT THAT ALSO SERVED AS A FOCUS
IT LOOKS LIKE ACTIVITY TODAY WILL BE LARGELY DRIVEN BY THE HEATING
OF THE DAY AND TERRAIN. THE BEST INSTABILITY AND MOISTURE STILL
LOOKS TO BE OVER MOHAVE COUNTY AND LINCOLN COUNTY AS WELL AS THE FAR
EASTERN PART OF SAN BERNARDINO COUNTY AND MOST OF CLARK COUNTY.
RADAR WAS ALREADY INDICATING A FEW CELLS POPPING UP IN SOUTHEAST
MOHAVE COUNTY AND EXPECT TO SEE THE COVERAGE OF STORMS INCREASE IN
THE EASTERN CWFA AS THE DAY PROGRESSES. THE CURRENT FORECAST LOOKS
GOOD AND DO NOT PLAN ANY CHANGES.
&&

.AVIATION...FOR MCCARRAN...ISOLATED THUNDERSTORMS EXPECTED MAINLY
EAST OF KLAS TODAY BUT ALSO FORMING OVER THE LOCAL MOUNTAINS BY 20Z
AND THEN CONTINUING THROUGH 03Z SATURDAY. CLOUDS TO GENERALLY BE SCT
AOA 8K FT WITH BKN LAYERS AOA 12K FT AS THUNDERSTORMS FORM.
SCATTERED THUNDERSTORMS ALSO EXPECTED ALONG THE PEACH SPRING AND
MORMON MESA CORRIDORS MAINLY BETWEEN 18Z FRIDAY AND 03Z SATURDAY.
LIGHT WINDS AT THE TERMINAL THEN BECOMING EAST AROUND 8-10KTS AFTER
20Z...THEN SOUTHWEST THIS EVENING. GUSTY AND ERRATIC WINDS NEAR ANY
SHOWERS.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...ISOLATED THUNDERSTORMS EXPECTED TODAY MAINLY EAST OF
KLAS...THEN SCATTERED THUNDERSTORMS EXPECTED MAINLY EAST OF A
NORTH/SOUTH LINE FROM RACHEL NEVADA TO ESSEX CALIFORNIA THROUGH 03Z
SATURDAY. CLOUDS TO GENERALLY BE SCT AOA 8K FT WITH BKN CLOUDS AOA
12K FT AFT 20Z AS THUNDERSTORMS FORM. WEST OF THE ABOVE MENTIONED
LINE TO BE FEW-SCT CLOUDS AOA 12K FT. WINDS SHOULD REMAIN BELOW
12KTS AWAY FROM THUNDERSTORMS...BUT GUSTS TO OVER 40KTS POSSIBLE
NEAR STORMS.
&&

.PREVIOUS DISCUSSION.../ISSUED AT 510 AM FRI JUL 3 2009/...
.UPDATE...WITH THE EXCEPTION OF MOHAVE COUNTY ARIZONA WHERE ISOLATED
THUNDERSTORMS ARE CONTINUING THIS MORNING...CLOUDS HAVE DISSIPATED
ELSEWHERE. WILL UPDATE GRIDS/ZONES TO REFLECT LESS CLOUD TO START
THE DAY ACROSS MOST AREAS. REMAINDER OF THE FORECAST REMAINS ON
TRACK.
&&

.PREVIOUS DISCUSSION.../ISSUED AT 320 AM PDT FRI JUL 3 2009/...
.SHORT TERM...ISOLATED THUNDERSTORMS HAVE CONTINUED OVERNIGHT AS
OUTFLOW BOUNDARIES INTERACT WITH EACH OTHER/HIGHER TERRAIN TO
PRODUCE GOOD LIFT. EXPECT ISOLATED ACTIVITY TO CONTINUE INTO THE
DAYLIGHT HOURS AND THEN INCREASE ACROSS THE EASTERN PORTION OF THE
CWA DURING THE DAY AS BEST DYNAMICS CONTINUE MAINLY TO THE EAST OF A
NORTH/SOUTH LINE FROM RACHEL NEVADA TO ESSEX CALIFORNIA. TO THE WEST
OF THIS LINE A SLOW DRYING WILL BE SEEN DURING THE DAY WITH MORE
STABLE CONDITIONS MOVING OVER THE AREA. SIMILAR TO THURSDAY...
TODAYS CONVECTION WILL HAVE THE POTENTIAL FOR LOCALLY HEAVY
RAIN...GUSTY WINDS...AND HAIL. HOWEVER...AREAL EXTEND OF THE
ACTIVITY DOES NOT WARRANT THE ISSUANCE OF A FLASH FLOOD WATCH BUT
WILL NEED TO BE CLOSELY MONITORED. THE SOUTHERLY FLOW BRINGING THE
MOISTURE INTO THE EASTERN PORTIONS WILL BE TURNING MORE SOUTHWEST ON
SATURDAY WITH THE DRIER CONDITIONS EXPERIENCED IN THE WESTERN
SECTIONS BEGINS TO MOVE FURTHER EAST. BY SATURDAY AFTERNOON
THUNDERSTORMS SHOULD BE CONFINED TO THE EASTERN PORTIONS OF LINCOLN
AND MOHAVE COUNTY. FURTHER DRYING ON SUNDAY AS SOUTHWEST FLOW ALOFT
CONTINUES IN RESPONSE TO A SHORT WAVE TROUGH MOVING INTO THE PACNW.
THIS WILL RESULT IN PUSHING THE MOISTURE/THUNDERSTORMS TO THE EAST
OF THE CWA. TEMPERATURES WILL WARM TODAY AND THEN CONTINUE NEAR TO
SLIGHTLY ABOVE NORMAL THROUGH THE REMAINDER OF THE WEEKEND.

.LONG TERM...LITTLE CHANGE TO THE FORECAST FOR THE PERIOD MONDAY
THROUGH THURSDAY AS A BROAD UPPER LOW OFF THE PACNW COAST IS
FORECAST TO DOMINATE THE WEATHER ACROSS THE WESTERN STATES. THIS
TROUGH WILL KEEP GENERALLY DRY WEST TO SOUTHWEST FLOW ACROSS THE
AREA THROUGH THE PERIOD. HOWEVER THE TROUGH IS EXPECTED TO DEEPEN ON
WEDNESDAY RESULTING IN LOWERING HEIGHTS/THICKNESS ACROSS THE CWA.
THIS SCENARIO WILL ALLOW FOR ABOVE NORMAL TEMPERATURES MONDAY AND
TUESDAY...THEN COOLING WEDNESDAY AND THURSDAY. IN ADDITION...LOCAL
GUSTY AFTERNOON WINDS MAY DEVELOP BY THE MIDDLE OF THE WEEK AS THE
TROUGH DEEPENS.
&&

.VEF WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
AZ...NONE.
CA...NONE.
&&