Damaging Wind in Arizona, June 29, 2015

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
250 PM PDT MON JUN 29 2015

.SYNOPSIS...HIGH PRESSURE WILL CONTINUE TO WOBBLE OVER UTAH AND
NEVADA THROUGH THE WEEK INTO THE WEEKEND KEEPING TEMPERATURES ABOVE
NORMAL. THERE WILL BE ENOUGH MOISTURE AND INSTABILITY IN PLACE FOR A
CHANCE OF THUNDERSTORMS EACH AFTERNOON AND EVENING...MAINLY OVER THE
MOUNTAINS AND MOHAVE COUNTY.
&&

.SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT.

STRONG HIGH PRESSURE WILL REMAIN CENTERED ROUGHLY OVER UTAH AND
NORTHERN NEVADA THROUGH THE SHORT TERM. THIS WILL KEEP TEMPERATURES
SEVERAL DEGREES ABOVE NORMAL. A SOUTHEAST FLOW ACROSS MOST OF OUR
FORECAST AREA HAS RESULTED IN PRECIPITABLE WATER VALUES INCREASING
TO ABOUT AN INCH AND A HALF IN THE FAR SOUTH WITH THE ONE INCH LINE
ACROSS THE FAR NORTHERN PART OF THE FORECAST AREA. THIS MOISTURE
WILL COMBINE WITH WEAK INSTABILITY TO KEEP A CHANCE OF THUNDERSTORMS
EACH AFTERNOON AND EVENING...MAINLY OVER THE MOUNTAINS AND MOHAVE
COUNTY. HOWEVER...WITH A DECENT AMOUNT OF MOISTURE IN
PLACE...OUTFLOW BOUNDARIES COULD GENERATE ISOLATED THUNDERSTORMS
EVEN IN SOME DESERT LOCATIONS. THE GFS IS INDICATING A WEAK WAVE
MOVING NORTHWEST INTO THE AREA THURSDAY WHICH COULD RESULT IN AN
UPTICK IN THUNDERSTORM ACTIVITY...ESPECIALLY OVER THE SIERRA AND
MAYBE OTHER PARTS OF INYO COUNTY. THIS FEATURE IS NOT SO EVIDENT IN
OTHER MODELS BUT IS WORTH WATCHING FOR IN LATER MODEL RUNS.

.LONG TERM...FRIDAY THROUGH MONDAY.

THE MEDIUM RANGE MODELS ARE STILL IN GOOD AGREEMENT AT DEPICTING A
STRONG RIDGE HOLDING THROUGH INDEPENDENCE DAY. THE CENTER OF THE
RIDGE IS FORECAST TO BE OVER NORTHWEST NEVADA THURSDAY THEN IT
SHOULD SLOWLY SLIDE TO THE SOUTHEAST FRIDAY AND SATURDAY WHICH WILL
TAKE IT OVER SOUTH CENTRAL NEVADA AND SOUTHWEST UTAH. THIS PATTERN
WILL STILL ALLOW A MODERATELY MOIST EAST-SOUTHEAST FLOW OVER MUCH OF
THE FORECAST AREA THURSDAY THEN THE MOISTURE WILL BE SHUNTED
SOUTHWARD FRIDAY AND SATURDAY WHILE WARMER AIR ALOFT UNDER THE HIGH
CENTER LIMITS INSTABILITY. ALSO...DRIER AIR COMING DOWN FROM IDAHO
AND UTAH IN THE NORTH-NORTHEAST FLOW WILL REDUCE THE POTENTIAL FOR
CONVECTION. SO...IT IS LOOKING VERY HOT AND MOSTLY DRY FOR THE
FOURTH OF JULY. TEMPERATURES OF 110-113 LOOK LIKELY OVER MUCH OF THE
MOJAVE DESERT REGION.

THE PATTERN WILL BEGIN TO CHANGE SUNDAY AND MONDAY AS MEDIUM RANGE
MODELS INDICATE THE HIGH WILL MIGRATE TOWARD THE FOUR CORNERS REGION
IN RESPONSE TO A BROAD EASTERN PACIFIC TROUGH. A BAND OF MOISTURE
BETWEEN THE RIDGE AND THE TROUGH WILL MOVE OVERHEAD SUNDAY AND
MONDAY LEADING TO A LITTLE MORE CLOUD COVER...SLIGHTLY LOWER
TEMPERATURES AND A SLIGHTLY INCREASED CHANCE OF THUNDERSTORMS OVER
THE HIGHER TERRAIN OF SOUTHERN NEVADA AND NORTHWEST ARIZONA.
&&

.AVIATION...FOR MCCARRAN...EAST TO SOUTHEAST WINDS MAY HANG ON UNTIL
AROUND 00Z THIS EVENING BUT SHOULD BECOME SOUTHERLY NEAR 10 KNOTS BY
THEN...PERSISTING THROUGH MUCH OF TONIGHT. THE CAVEAT IS THAT
OUTFLOW BOUNDARIES FROM STORMS OVER NORTHWEST ARIZONA COULD CAUSE
GUSTY AND ERRATIC WINDS AT TIMES THROUGH THIS EVENING. LIGHT WINDS
FAVORING AN EASTERLY DIRECTION ARE EXPECTED MUCH OF TUESDAY UNTIL
LATE AFTERNOON WHEN SOUTHWEST WINDS SHOULD DEVELOP. THUNDERSTORMS
ARE EXPECTED TO REMAIN CONFINED TO THE MOUNTAINS AND NORTHWEST
ARIZONA THROUGH TUESDAY.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...THROUGH TUESDAY...AWAY FROM SHRA/TSRA WINDS WILL MAINLY
FAVOR TYPICAL DIURNAL DIRECTIONS AT 10 KTS OR LESS EXCEPT IN THE
AFTERNOON AND EARLY EVENING WHEN THEY PICK UP FROM THE SOUTH TO
SOUTHWEST AT 10-15 KTS WITH GUSTS OF 20-25 KTS. SHRA/TSRA ARE
POSSIBLE THROUGH EARLY THIS EVENING AND AGAIN TUESDAY
AFTERNOON/EVENING ACROSS MOHAVE COUNTY AS WELL AS IN THE HIGHER
ELEVATIONS OF CLARK, LINCOLN, INYO AND EASTERN SAN BERNARDINO.
SHRA/TSRA OVER MOHAVE COUNTY MAY SURVIVE FAR ENOUGH TO THE WEST TO
GENERATE SOME STRONGER OUTFLOW WINDS AND PATCHY BLDU TOWARD KIFP,
KEED AND KHII THIS EVENING. MAINLY SCT-BKN CLOUDS AOA 15K FEET WITH
BASES AS LOW AS 6K-10K FEET IN AND NEAR ANY SHRA/TSRA. &&

.FIRE WEATHER...THERE IS SOME THREAT OF ISOLATED DRY LIGHTNING WITH
STORMS. HOWEVER...MOISTURE LEVELS HAVE INCREASED AND THERE IS NOW A
HIGHER PROBABILITY OF STORMS PRODUCING WETTING RAINS...ESPECIALLY
ACROSS MOHAVE...CLARK...INYO AND SAN BERNARDINO COUNTIES.
&&

.CLIMATE...SEE THE GRAPHIC POSTED TO OUR WEBPAGE AND SOCIAL MEDIA
SITES. LAS VEGAS WILL BE AT RISK TO SEE THE WARMEST JUNE ON RECORD.
THE RECORD NUMBER OF DAYS WITH A HIGH OF 105 OR GREATER IN JUNE OF
18 WILL LIKELY BE TIED TOMORROW. WE ALSO WILL KEEP THE CONSECUTIVE
DAYS OF 105 OR GREATER FOR ANY MONTH GOING WHICH MAY BREAK THE ALL-
TIME RECORD STRETCH OF 21 DAYS SET 4 TIMES WITH THE LAST TIME BEING
IN 2000. LASTLY 2 DAYS SO FAR THIS MONTH HAD A LOW OF 90 OR
GREATER WHICH IS A HITHERTO UNKNOWN FOR JUNE.
&&

.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT EXPECTED
AT THIS TIME. HOWEVER...SPOTTERS ARE ENCOURAGED TO REPORT ANY
SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&

SHORT TERM/AVIATION/FIRE WEATHER...HARRISON
CLIMATE...STACHELSKI
LONG TERM...ADAIR

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