Area Forecast Discussion
Issued by NWS Reno, NV

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000
FXUS65 KREV 292154
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
254 PM PDT SAT AUG 29 2015

.SYNOPSIS...

WINDS WILL DECREASE THIS EVENING AS LOW PRESSURE EXITS THE PACIFIC
NORTHWEST. A FEW LIGHT SHOWERS ARE POSSIBLE EAST OF HIGHWAY 95
THIS EVENING, OTHERWISE DRY WEATHER WILL PREVAIL FOR THE UPCOMING
WEEK. TYPICAL LATE DAY BREEZES WITH SLIGHTLY BELOW NORMAL
TEMPERATURES ARE EXPECTED SUNDAY AND MONDAY. ANOTHER AREA OF LOW
PRESSURE MAY BRING INCREASED WINDS AND FURTHER COOLING BY MIDWEEK.

&&

.SHORT TERM...

WE WILL KEEP THE WIND HEADLINES IN PLACE FOR THIS AFTERNOON. MOST
ADVISORIES ARE SCHEDULED TO EXPIRE AT 6 PM, WHEN WIND SPEEDS ARE
LIKELY TO START DECREASING. WIND GUSTS HAVE GENERALLY REMAINED IN
THE 35-40 MPH RANGE SO FAR THIS AFTERNOON, EXCEPT FOR SOME LOCAL
GUSTS AROUND 45 MPH. RIDGE TOP GUSTS HAVE GENERALLY RANGED FROM
50-60 MPH FOR MUCH OF THE DAY.

SMOKE AND HAZE FROM THE ROUGH FIRE CLEARED UP FROM THE MAMMOTH
LAKES AREA DURING THE EARLY AFTERNOON, AND WIND TRAJECTORIES
SHOULD LIMIT HAZE TO FAR SOUTHEAST MONO COUNTY TONIGHT AND SUNDAY.

FOR THIS EVENING, THE GFS HAS MAINTAINED AN AREA OF SLIGHT
INSTABILITY AND UPPER LEVEL JET DYNAMICS IN WEST CENTRAL NV, AS A
WEAK UPPER WAVE IN THE POST FRONTAL AIR MASS MOVES OVER THIS AREA.
ISOLATED BANDS OF LIGHT RAIN SHOWERS COULD STILL DEVELOP NEAR AND
EAST OF HIGHWAY 95, BUT THUNDERSTORMS AND WETTING RAINS ARE
UNLIKELY.

FOR SUNDAY AND MONDAY, LIGHTER SOUTHWEST-WEST FLOW ALOFT WILL LEAD
TO LATE DAY ZEPHYR-TYPE BREEZES, WITH GUSTS GENERALLY 20-25 MPH
EACH DAY. MAX TEMPS ON SUNDAY WILL REMAIN A FEW DEGREES BELOW
NORMAL, MAINLY IN THE 80S FOR WESTERN NV AND 70-75 FOR SIERRA
VALLEYS, THEN EDGE UPWARD ABOUT 3-6 DEGREES FOR MONDAY. DRY AIR
MASS AND SPARSE CLOUD COVER SUNDAY NIGHT WILL PRODUCE RATHER
CHILLY CONDITIONS, WITH LOWS DROPPING INTO THE 40S FOR MOST OF
WESTERN NV, AND UPPER 30S POSSIBLE IN TYPICALLY COOLER LOWER
ELEVATION SITES. THE COLDER VALLEYS NEAR THE SIERRA AND IN
NORTHEAST CA COULD EVEN DROP TO NEAR FREEZING. MJD

.LONG TERM...TUESDAY THROUGH SATURDAY...

LIMITED CHANGES WERE MADE TO THE CURRENT EXTENDED FORECAST TODAY AS
THE MEDIUM RANGE OPERATIONAL MODELS ARE NOT IN VERY GOOD AGREEMENT
BEYOND WEDNESDAY.

INCOMING TROUGH FOR TUESDAY SHOULD PUSH HIGH TEMPS ABOVE AVERAGE...
THEN THE CORE OF THE UPPER LOW MOVES INTO THE PAC NW FOR WEDNESDAY
AND THURSDAY. EARLIER MODEL RUNS SHOWED COLDER AIR DIPPING FARTHER
SOUTH AS THE TROUGH AMPLIFIED...BUT NOW THE OPERATIONAL GFS HAS
BACKED OFF THIS COLDER SOLUTION A LITTLE. THE ECMWF REMAINS DEEPER
WITH THE TROUGH AND IS ALSO LESS PROGRESSIVE WITH LIFTING IT OUT.
THE GFS SWINGS THE MOST VIGOROUS PART OF THE TROUGH THROUGH THE
REGION LATE THURSDAY AND EARLY FRIDAY MORNING, WHILE THE ECMWF
HOLDS ON TO THE AMPLIFIED TROUGH LATE FRIDAY NIGHT.

THE GEFS ENSEMBLE MEMBERS ARE SPLIT WITH SOME SUPPORTING THE
OPERATIONAL GFS AND OTHERS MORE CLOSELY RESEMBLING THE ECMWF. GIVEN
THE INCONSISTENCIES BETWEEN THE MODELS...WILL OPT TO LIMIT THE
CHANGES TO THE FORECAST. WILL KEEP TEMPS AT A MIDDLE GROUND...
SOMEWHERE BETWEEN THE WARMER GFS AND THE COLDER ECMWF. THIS ALSO
AFFECTS THE WIND FORECAST. GUSTY WINDS ARE POSSIBLE BOTH WEDNESDAY
AND THURSDAY...BUT THE STRONGEST APPEARS TO BE WEDNESDAY. WILL ADD
A SLIGHT CHANCE OF POPS NEAR THE OREGON BORDER FOR THURSDAY AS THE
CORE OF THE TROUGH MOVES OVERHEAD. 20

&&

.AVIATION...

SURFACE COLD FRONT ASSOCIATED WITH THE UPPER LOW IN THE PAC NW WILL
CONTINUE TO PUSH EAST TONIGHT. AS THIS FRONT MOVES AWAY THE WINDS
SHOULD BEGIN TO DECREASE THROUGH THE EVENING. TERMINALS EARLY THIS
EVENING COULD STILL SEE GUSTS IN THE 30-35 KT RANGE...ESPECIALLY
EAST OF THE SIERRA...ALONG WITH TURBULENCE INDUCED BY FLOW OVER THE
MOUNTAINS. AS THE WIND DIRECTION AT THE SURFACE SHIFTS TO THE WEST
THEN WEST-NORTHWEST...LOW LEVEL WIND SHEAR SHOULD BE LESS OF A
POSSIBILITY.

WINDS AT ALL LEVELS DECREASE FOR SUNDAY WITH TYPICAL AFTERNOON GUSTS
IN THE 20-25 KT RANGE.

SMOKE AND HAZE NEAR KMMH SHOULD REMAIN SOUTH OF THE TERMINAL
THROUGH TONIGHT AND SUNDAY AS WINDS SHIFT TO MORE OF A WESTERLY
TO NORTHWEST DIRECTION. THE FLOW BECOMES MORE SOUTHWEST AGAIN ON
MONDAY AND THIS COULD DRAW SMOKE AND HAZE BACK INTO THE AREA OF
KMMH. 20

&&

.FIRE WEATHER...

WINDS DID NOT MATERIALIZE AS STRONG AS ANTICIPATED TODAY, BUT MANY
VALLEYS ACROSS THE SIERRA AND WESTERN NEVADA HAVE SEEN GUSTS IN THE
35 TO 45 MPH RANGE, WITH GUSTS PEAKING AROUND 65 MPH IN THE SIERRA.
WILL KEEP CURRENT RED FLAG WARNINGS IN PLACE FOR THE EASTERN SIERRA
SOUTH OF HIGHWAY 50 AND MUCH OF WESTERN NEVADA THROUGH 6 PM THIS
EVENING. WHILE RELATIVE HUMIDITY VALUES ARE HIGHER THAN WHAT IS
TYPICAL OF LATE AUGUST, THEY WILL STILL BE IN THE 15-25 PERCENT
RANGE AND WIND SPEEDS ALONG WITH DRY FUELS ARE CREATING CRITICAL
CONDITIONS. WINDS ARE EXPECTED TO DECREASE OVERNIGHT WITH MORE
TYPICAL SPEEDS ON SUNDAY AND MONDAY.

HUMIDITY RECOVERIES WILL BE GOOD TONIGHT, BUT WITH DRIER AIR
RETURNING SUNDAY, TYPICAL LOW AFTERNOON HUMIDITIES WILL RETURN
SUNDAY. DJ

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...BLOWING DUST ADVISORY UNTIL 6 PM PDT THIS EVENING NVZ004.

     RED FLAG WARNING UNTIL 6 PM PDT THIS EVENING NVZ450-453-459.

     LAKE WIND ADVISORY UNTIL 3 AM PDT SUNDAY NVZ002.

     WIND ADVISORY UNTIL 6 PM PDT THIS EVENING NVZ003.

CA...RED FLAG WARNING UNTIL 6 PM PDT THIS EVENING CAZ273.

     WIND ADVISORY UNTIL 6 PM PDT THIS EVENING CAZ073.

     LAKE WIND ADVISORY UNTIL 3 AM PDT SUNDAY CAZ072.

&&

$$

FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)


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