Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 022226
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
326 PM PDT WED SEP 2 2015

.SYNOPSIS...

A LOW PRESSURE SYSTEM WILL PROVIDE WINDY CONDITIONS THROUGH FRIDAY.
THIS WILL RESULT IN HAZARDOUS BOATING ON AREA LAKES, BLOWING
DUST, AND AREAS OF CRITICAL FIRE WEATHER CONDITIONS. A FRONT WILL
PUSH THROUGH THE REGION AND PROVIDE COOLER TEMPERATURES WHICH WILL
REMAIN BELOW SEASON AVERAGES THROUGH THE WEEKEND.

&&

.SHORT TERM...

GUSTY WINDS AND COOLING TEMPERATURES WILL BE THE MAIN STORY FOR THE
NEXT FEW DAYS AS A LOW PRESSURE SYSTEM APPROACHES THE REGION. DRY
AND GUSTY CONDITIONS HAVE DEVELOPED THIS AFTERNOON AND EXPECT 30-35
MPH GUSTS TO LAST THROUGH THE EVENING. ON THURSDAY, WINDS WILL
REMAIN GUSTY WITH SLIGHTLY WEAKER SPEEDS AS COMPARED TO TODAY BUT
WILL STILL PRODUCE ALL ASSOCIATED HAZARDS INCLUDING CHOPPY AREA
LAKES AND CONTINUED AREAS OF BLOWING DUST. A FEW LIGHT SHOWERS
WILL BE POSSIBLE ACROSS FAR NORTHERN WASHOE COUNTY BUT LITTLE IN
THE WAY OF MEANINGFUL PRECIPITATION ACCUMULATION.

THE MAIN CONCERN WILL BE ON FRIDAY WHEN WE EXPECT THE STRONGEST
WINDS OF THE WEEK TO OCCUR. THE LOW PRESSURE CENTER WILL BE
CENTERED ACROSS NORTHERN CALIFORNIA AND WILL PLACE AN UPPER LEVEL
JET SEGMENT ACROSS THE SIERRA. GUSTS IN THE 40-45 MPH RANGE FRIDAY
AFTERNOON WILL MAKE FOR VERY HAZARDOUS CONDITIONS ON AREA LAKES
AND WILL LIKELY RESULT IN WIDESPREAD AREAS OF BLOWING DUST NEAR
AND DOWNSTREAM OF DESERT REGIONS AND DRY LAKE BEDS. THIS WILL
IMPACT THE BURNING MAN FESTIVAL IN BLACK ROCK CITY WHERE GREATLY
REDUCED VISIBILITY IS POSSIBLE. LOOSE OBJECTS MAY BECOME AIRBORNE
HAZARDS AND DRIVING MAY BE HAZARDOUS TO PEDESTRIAN TRAFFIC ON THE
PLAYA.

PRECIPITATION IS POSSIBLE ACROSS NORTHERN LASSEN COUNTY AND FAR
NORTHERN WASHOE COUNTY FRIDAY AFTERNOON AS THE LOW NEARS
NORTHWESTERN NEVADA. MOISTURE AND INSTABILITY IS MODEST BUT DYNAMIC
FORCING MAY PROVIDE A SLIGHT CHANCE FOR THUNDERSTORM FORMATION.
OVERALL, TEMPERATURES WILL COOL THROUGH THE WEEK WITH HIGHS ONLY
REACHING INTO THE MID AND UPPER 70S BY FRIDAY AND MID 60S ACROSS THE
SIERRA. COLD NIGHTS ARE EXPECTED WITH SIERRA VALLEYS DIPPING INTO
THE 20S AND 30S WHILE A FEW COLDER NEVADA VALLEYS COULD SEE
OVERNIGHT LOWS IN THE 30S. FUENTES


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

NO MAJOR CHANGES MADE FOR THE LONG TERM FORECAST. UPPER LEVEL TROUGH
WILL BE SLOWLY MAKING ITS EXIT LATE SATURDAY LEAVING BEHIND COOLER
TEMPERATURES AND SOME SMALL CHANCES FOR PRECIPITATION. THE ECMWF
REMAINS DRIER THAN THE GFS WITH CURRENT MODELS RUNS, BUT STILL SEEMS
LIKE SHOWERS COULD REACH AS FAR SOUTH AS HIGHWAY 50 FOR THE WEEKEND.
THE BEST CHANCES FOR PRECIPITATION STILL APPEAR TO BE NORTH OF
INTERSTATE 80 UP TO THE NEVADA/OREGON BORDER.

TEMPERATURES WILL BE MUCH COOLER ON SATURDAY WITH EVEN COLDER
TEMPERATURES EXPECTED FOR EARLY SUNDAY MORNING. A FREEZE AND/OR
FROST WILL BE POSSIBLE FOR SIERRA VALLEYS AND ALSO FOR SOME OF THE
COLDER VALLEYS IN WESTERN NEVADA.

TEMPERATURES WILL BEGIN TO WARM BACK INTO THE 70S FOR THE SIERRA AND
80S FOR WESTERN NEVADA BY LABOR DAY AND TUESDAY ALONG WITH DRY
CONDITIONS. MODEL SOLUTIONS BEGIN TO DIVERGE BY WEDNESDAY/THURSDAY
WITH THE ECMWF SHOWING A RIDGE DEVELOPING AND THE GFS HOLDING A WEAK
TROUGH ALONG THE COAST. IF THE WEAK TROUGH DEVELOPS THERE COULD BE
SOME LOW CHANCES FOR SHOWERS/THUNDERSTORMS ALONG THE SOUTHERN SIERRA
BY MIDWEEK. WEISHAHN

&&

.AVIATION...

INCREASING WINDS WILL LEAD TO LEE SIDE TURBULENCE AND AREAS OF
BLOWING DUST ACROSS WESTERN NV THIS AFTERNOON AND EVENING. THE
STRONGEST WINDS WILL BE ALONG THE SIERRA FRONT AND NORTH OF HIGHWAY
50 WHERE GUSTS WILL APPROACH 35KT (RIDGE GUSTS WILL REACH AROUND
50KT). VISIBILITY WILL DROP TO ONE MILE AT TIMES IN BLOWING DUST
DOWNWIND OF DRY SINKS AND LAKE BEDS.

LOW PRESSURE SYSTEM WILL CONTINUE TO BRING GUSTY AFTERNOON WINDS THU-
FRI WITH GUSTS 25-30KT. THE LOW DROPS SOUTHWARD ON FRIDAY ALLOWING
FOR ENOUGH MOISTURE AND INSTABILITY TO WARRANT A SLIGHT CHANCE OF
THUNDERSTORMS ACROSS FAR NORTHEAST CA AND NORTHWEST NV GENERALLY
NORTH OF A SUSANVILLE TO GERLACH LINE). AS THE LOW MOVES SOUTHEAST
SATURDAY SHOWERS MAY DEVELOP AS FAR SOUTH AS HIGHWAY 50. WEISHAHN

&&


.FIRE WEATHER...

LOOKING AT CURRENT CONDITIONS IN RELATION TO THE RED FLAG
WARNINGS, MANY SITES ARE GUSTING BETWEEN 25-30 MPH IN THE TAHOE
BASIN, SIERRA FRONT AND UP INTO EASTERN LASSEN AND NORTHERN WASHOE
COUNTIES, WITH HUMIDITIES RUNNING IN THE 10-18% RANGE IN THE BASIN
AND 20-25% FOR THE TAHOE BASIN. THIS PUTS THE RED FLAG AREAS IN
DECENT POSITION TO HIT THE "LOW-END" CRITERIA EXPECTED WITH THE
EVENT IN THE NEXT FEW HOURS.

TONIGHT, WINDS MAY LINGER UNTIL AFTER MIDNIGHT ON SLOPES AND IN THE
HIGHER TERRAIN (ESPECIALLY NORTH OF HIGHWAY 50) AS THE GFS/NAM SHOW
20-35 KTS AT 700 MB PERSISTING OVERNIGHT AS THE PAC NW TROUGH
CONTINUES TO SAG SOUTHWARD.

THURSDAY, IT WILL BE BREEZY AGAIN (25-30 MPH, LOCALLY 35) IN THE
AFTERNOON AS A COLD FRONT HANGS UP OVER NORTHERN CALIFORNIA AND
NORTHWEST NEVADA. HOWEVER, TEMPERATURES WILL COOL SO HUMIDITIES ARE
EXPECTED TO REMAIN MOSTLY ABOVE CRITICAL THRESHOLDS. WITH THE GUSTS
OVER 30 MPH BEING MORE LOCALIZED AND HUMIDITIES MOSTLY AT OR ABOVE
15%, WE CONTINUE TO JUST HIGHLIGHT THE BREEZY WINDS FOR THURSDAY.

FRIDAY, THE FORECAST HAS BECOME A BIT MORE UNCERTAIN REGARDING WINDS
AND HUMIDITIES. THE GFS/NAM MODEL SOUNDINGS OVER THE NORTHERN SIERRA
AND ALONG THE SIERRA FRONT ARE SHOWING A DRY SLOT DEVELOPING NEAR
AND ABOVE 600 MB LATE IN THE DAY AS A 70-80 KT JET STREAK MOVES
OVERHEAD. MODELS DO NOT MIX UP TO THIS LEVEL, SO THEY ARE NOT MIXING
DOWN THE DRY AIR OR THE 35-50 KT FLOW ABOVE THE MIXED LAYER ON
FRIDAY. HOWEVER, IT IS POSSIBLE THAT MODELS ARE UNDER-MIXING BASED
ON EXPECTED HIGH TEMPERATURES FRIDAY SO THERE IS CONCERN FOR MORE
WIND AND LOWER HUMIDITIES THAN ARE CURRENTLY ADVERTISED IN THE
FORECAST. FOR NOW, HUMIDITIES ARE NOT IN THE CRITICAL RANGE FOR MOST
SPOTS. HOWEVER, WINDS WILL BE GUSTING 35-40 MPH (UP TO 45 MPH ON
SLOPES, WIND PRONE AREAS) IN THE SIERRA, OUT INTO THE SIERRA FRONT
AND POSSIBLY OUT INTO PORTIONS OF THE WEST-CENTRAL BASIN AND RANGE
SO ANY MIXING DOWN OF DRIER AIR MAY PUSH THE AREA TO CRITICAL
THRESHOLDS. SNYDER

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...RED FLAG WARNING UNTIL 9 PM PDT THIS EVENING NVZ450-453-458.

     BLOWING DUST ADVISORY UNTIL 9 PM PDT THIS EVENING NVZ004-005.

     LAKE WIND ADVISORY UNTIL 9 PM PDT THIS EVENING NVZ002.

     LAKE WIND ADVISORY UNTIL 9 PM PDT THIS EVENING FOR PYRAMID LAKE
     IN NVZ004.

CA...RED FLAG WARNING UNTIL 9 PM PDT THIS EVENING CAZ278.

     LAKE WIND ADVISORY UNTIL 9 PM PDT THIS EVENING CAZ071.

     RED FLAG WARNING UNTIL 7 PM PDT THIS EVENING CAZ272.

     LAKE WIND ADVISORY UNTIL 9 PM PDT THIS EVENING CAZ072.

&&

$$

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



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