Weather Service Report


333 
FXUS65 KREV 020408
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
908 PM PDT TUE SEP 1 2015

.UPDATE...

WITH WIND GUSTS EXPECTED TO INCREASE GREATER THAN 30 KNOTS OVER
THE SMOKE CREEK AND BLACK ROCK DESERTS, HAVE ADDED A BLOWING DUST
ADVISORY FOR THESE AREAS OF NORTHERN WASHOE AND NORTHERN PERSHING
COUNTIES. THIS INCLUDES GERLACH AND BLACK ROCK CITY WHICH
EXPERIENCED QUITE A BIT OF DUST WITH SIMILAR CONDITIONS LAST
SATURDAY. THE WORST CONDITIONS WILL BE FROM 1 PM THROUGH AROUND 9
PM WHICH IS WHEN THE ADVISORY IS VALID. HOWEVER, DUST WILL BEGIN
TO LOFT EARLIER AND LIKELY SETTLE AFTER 9 PM DUE TO LIGHTER GUSTS
AND THE AMOUNT OF ACTIVITY ON THE PLAYA. CONCERNS INCLUDE LIMITED
REACTION TIMES FOR DRIVERS ENCOUNTERING PEDESTRIANS, POTENTIAL
DAMAGE TO POORLY SECURED OUTDOOR EQUIPMENT, AND HEALTH CONCERNS
FOR THOSE WITHOUT EYE PROTECTION OR BREATHING MASKS. BOYD

&&

.PREVIOUS DISCUSSION... /ISSUED 304 PM PDT TUE SEP 1 2015/ 

SYNOPSIS...

A LOW PRESSURE SYSTEM WILL INCREASE WINDS WEDNESDAY AND THURSDAY. 
THIS WILL RESULT IN CRITICAL FIRE WEATHER CONDITIONS AND ALSO 
HAZARDOUS BOATING ON TAHOE AND PYRAMID LAKES WEDNESDAY AFTERNOON.
A FRONT WILL PUSH THROUGH THE REGION AND PROVIDE COOLER
TEMPERATURES WHICH WILL REMAIN BELOW SEASON AVERAGES THROUGH THE
WEEKEND.

SHORT TERM...

AN UPPER LEVEL LOW PRESSURE CENTER OVER THE PACIFIC NORTHWEST WILL 
BEGIN TO INCREASE WINDS ACROSS THE REGION WEDNESDAY AFTERNOON. THE 
GUSTIER WINDS WILL BE LOCATED ROUGHLY NORTH OF HWY 50 THROUGH THE 
TAHOE BASIN AND LASSEN COUNTY AND EXTENDING INTO WESTERN NEVADA. THE 
COMBINATION OF GUSTY WINDS AND DRY CONDITIONS WILL CREATE AREAS OF 
CRITICAL FIRE WEATHER CONDITIONS AND A RED FLAG WARNING IS IN PLACE 
FOR TOMORROW AFTERNOON AS A RESULT. SEE THE FIRE WEATHER DISCUSSION 
BELOW FOR ADDITIONAL DETAILS ON THE EXPECTED CONDITIONS. HAZARDOUS 
BOATING IS LIKELY ACROSS LAKE TAHOE AND PYRAMID LAKE WITH GUSTS
IN THE 30-35 MPH RANGE EXPECTED. LAKE WIND ADVISORIES HAVE ALSO
BEEN ISSUED WEDNESDAY AFTERNOON. ADDITIONALLY, AREAS OF BLOWING
DUST ARE POSSIBLE MAINLY FOR AREAS DOWNWIND OF DESERT SINKS AND
DRY LAKE BEDS. THIS ALSO INCLUDES BLACK ROCK DESERT AND THE
BURNING MAN FESTIVAL.

BREEZY AND COOLER CONDITIONS WILL PREVAIL ON THURSDAY AS A SURFACE 
FRONT PUSHES ACROSS THE REGION. HUMIDITY VALUES WILL INCREASE SOME 
AND SHOULD PREVENT WIDESPREAD CRITICAL FIRE WEATHER CONDITIONS. 
HOWEVER, HAZARDOUS BOATING CONDITIONS AND AREAS OF BLOWING DUST ARE 
STILL POSSIBLE FOR THURSDAY AFTERNOON. HIGHS ON THURSDAY WILL DIP A 
FEW DEGREES BELOW SEASONAL AVERAGES WITH GENERALLY UPPER 70S 
EXPECTED ACROSS WESTERN NEVADA AND UPPER 60S TO NEAR 70 FOR SIERRA 
VALLEYS. FREEZING TEMPERATURES WILL BECOME MORE WIDESPREAD OVERNIGHT 
THURSDAY ACROSS THE SIERRA VALLEYS WITH 20S POSSIBLE IN THE COLDEST 
SIERRA LOCATIONS SUCH AS BOCA AND BODIE. FUENTES

LONG TERM...FRIDAY THROUGH MONDAY...
NO MAJOR ADJUSTMENTS MADE TO THE LONG TERM FORECAST TODAY. MODELS 
CONTINUE TO SHOW A PROGRESSION TOWARDS COOLER TEMPERATURES WITH 
SMALL CHANCES FOR PRECIPITATION LATE THIS WEEK GOING INTO THE 
HOLIDAY WEEKEND. 

OPERATIONAL MODELS IN GOOD AGREEMENT THROUGH SATURDAY WITH TRACKING 
AN AREA OF LOW PRESSURE ACROSS THE NORTHERN PORTIONS OF NEVADA AND 
CALIFORNIA FRIDAY AND SATURDAY. MAIN IMPACTS WILL BE COOLER 
TEMPERATURES WITH SOME BREEZY CONDITIONS ON FRIDAY 
AFTERNOON/EVENING. HIGH TEMPERATURES ACROSS THE REGION WILL DROP 
INTO THE 70S ACROSS WESTERN NEVADA AND THE 60S FOR THE SIERRA. 
OVERNIGHT TEMPERATURES MAY DROP INTO THE 30S AND 40S ALONG WITH THE 
POTENTIAL FOR FREEZE OR FROST FOR MANY SIERRA VALLEYS AND FOR SOME 
OF THE USUALLY COLDER VALLEYS IN WESTERN NEVADA. PRECIPITATION-WISE 
THIS SYSTEM WILL NOT BE IMPRESSIVE, WITH ONLY CHANCES FOR RAIN 
SHOWERS RIGHT ALONG THE NEVADA-OREGON BORDER FOR NOW. 

FOR THE REMAINDER OF THE LABOR DAY WEEKEND, NORTHEAST-EAST WINDS ARE 
LIKELY ACROSS THE SIERRA AND WESTERN NEVADA. TEMPERATURES WILL BEGIN 
TO WARM TO NEAR SEASONAL NORMALS BY EARLY NEXT WEEK. WEISHAHN 

AVIATION... 

MOST LOCATIONS WILL REMAIN VFR THROUGH MIDWEEK, ALTHOUGH SOME LOCAL 
IMPACTS WILL OCCUR DUE TO INCREASED WINDS ON WEDNESDAY.  WINDS 
INCREASE THIS AFTERNOON WITH GUSTS MAINLY 20-25 KT, BUT WILL THEN 
STRENGTHEN ON WEDNESDAY WITH GUSTS 30-35 KT MAINLY NORTH OF HIGHWAY 
50 AND WEST OF HIGHWAY 95. TYPICAL SOUTHWEST WINDS THIS AFTERNOON 
SHOULD HELP TO IMPROVE SLANTWISE VISIBILITY LIMITATIONS FROM THE 
SMOKE LATE THIS AFTERNOON AND EVENING. 

AVIATION IMPACTS WILL BE MORE SIGNIFICANT IN THE VICINITY OF THE 
BLACK ROCK DESERT. BLOWING DUST WILL LEAD TO REDUCED VISIBILITIES, 
AROUND 1 MILE OR LESS AT TIMES, ESPECIALLY ON WEDNESDAY. WEISHAHN

FIRE WEATHER...

NO BIG CHANGE IN THINKING FOR WINDS AND HUMIDITIES WEDNESDAY AFTERNOON 
AND EVENING IN THE RED FLAG AREA (278/SOUTHERN 458/450/453). FOR THE 
SURPRISE VALLEY/ZONE 270 AND ZONE 271 (WESTERN LASSEN, EASTERN 
PLUMAS/SIERRA/NEVADA COUNTIES), GUSTS TO 35 MPH WILL BE POSSIBLE. 
HOWEVER, IN THOSE AREAS HUMIDITY IS EXPECTED TO REMAIN TOO MARGINAL 
AND MOSTLY ABOVE 15% SO I JUST HIGHLIGHTED THOSE AREAS FOR BREEZY 
CONDITIONS.

IF THERE IS ONE AREA THAT I HAVE SLIGHT CONCERN FOR ON WEDNESDAY IT 
IS THE TAHOE BASIN. THE 18Z NAM HAS COME IN WITH STRONGER FLOW ALOFT 
WHICH COULD PUSH SOME WIND GUSTS TOWARDS 35 MPH VERSUS 25-30 MPH. 
ALSO, THE NAM IS SHOWING DRIER AIR ALOFT WHICH COULD PARTIALLY MIX 
DOWN INTO THE BASIN FOR SLIGHTLY LOWER HUMIDITIES THAN CURRENTLY 
ADVERTISED. FOR NOW, THE HUMIDITY FORECAST REMAINS MARGINAL SO I 
HAVE HEADLINED BREEZY CONDITIONS IN THE TAHOE BASIN ZONE.

WEDNESDAY NIGHT, WINDS MAY LINGER UNTIL AFTER MIDNIGHT ON SLOPES AND 
IN THE HIGHER TERRAIN AS THE GFS/NAM SHOW 25-35 KTS AT 700 MB 
PERSISTING OVERNIGHT NEAR/NORTH OF HIGHWAY 50 AS THE PAC NW TROUGH 
CONTINUED TO SAG SOUTHWARD. 

THURSDAY, WINDS WILL BECOME GUSTY AGAIN (25-35 MPH) 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. THEREFORE, I HAVE JUST 
HIGHLIGHTED THE BREEZY WINDS FOR NOW. SNYDER

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...RED FLAG WARNING FROM 1 PM TO 9 PM PDT WEDNESDAY NVZ450-453-458.

     BLOWING DUST ADVISORY FROM 1 PM TO 9 PM PDT WEDNESDAY NVZ004-005.

     LAKE WIND ADVISORY FROM 1 PM TO 9 PM PDT WEDNESDAY FOR LAKE 
     TAHOE IN NVZ002.

     LAKE WIND ADVISORY FROM 1 PM TO 9 PM PDT WEDNESDAY FOR PYRAMID 
     LAKE IN NVZ004.

CA...RED FLAG WARNING FROM 1 PM TO 9 PM PDT WEDNESDAY CAZ278.

     LAKE WIND ADVISORY FROM 1 PM TO 9 PM PDT WEDNESDAY FOR LAKE 
     TAHOE IN CAZ072.

&&

$$

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

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