Area Forecast Discussion
Issued by NWS Reno, NV

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000
FXUS65 KREV 021005 CCA
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
240 AM PDT WED SEP 2 2015

.SYNOPSIS...

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

&&

.SHORT TERM...

A FEW MODEST CHANGES WERE MADE TO THE EXISTING FORECAST BASED ON
RECENT MODEL TRENDS. INCREASED WINDS THIS AFTERNOON MARGINALLY;
WIND GUSTS ON THE ORDER OF 30-35 MPH AND INTERMITTENTLY UP TO 40
MPH. ALSO, ISSUED A BLOWING DUST ADVISORY FOR THE SMOKE CREEK AND
BLACK ROCK DESERTS INCLUDING ADJACENT AREAS AND THE LOCATIONS OF
GERLACH AND BLACK ROCK CITY. CONDITIONS WILL BE SIMILAR TO LAST
SATURDAY ON THE PLAYA AND WILL HAVE AN IMPACT TO BURNING MAN
FESTIVITIES. DUST WILL BEGIN TO LOFT AFTER 11 IN THE MORNING AND
CONTINUE THROUGH AROUND MIDNIGHT WITH THE WORST CONDITIONS
OCCURRING FROM 1 PM TO 9 PM. DUST WILL BE SLOWER TO SETTLE THAN
USUAL CONSIDERING THE AMOUNT OF ACTIVITY THAT WILL BE OCCURRING ON
THE PLAYA.

EXTRA CARE SHOULD BE EXERCISED BY DRIVERS ON THE PLAYA AS DUST
WILL LIMIT VISIBILITY REDUCING REACTION TIMES AROUND PEDESTRIANS.
ALSO, WITH GUST POTENTIALS UP TO 40 MPH, POORLY SECURED OUTDOOR
GEAR MAY BE DAMAGED OR BECOME A PROJECTILE. FINALLY, HEALTH
CONCERNS WILL BE PRESENT FOR THOSE WITHOUT EYE OR BREATHING
PROTECTION.

ENDED UP ADJUSTING TEMPERATURES A LITTLE WARMER TONIGHT AS WINDS
WILL BE SLOWER TO DECREASE. OTHERWISE, BREEZY AND COOLER
TEMPERATURES ARE EXPECTED THURSDAY AS WELL. SOME DUST WILL BE
LOFTED AGAIN, BUT THE IMPACTS SHOULD BE LOWER THAN TODAY SINCE
WIND SPEEDS WILL BE SLOWER. STILL, GUSTS UP TO 30 MPH COULD
PRODUCE REDUCTION OF VISIBILITY DOWN TO AROUND 1 MILE AT TIMES.

INCREASED PRECIPITATION CHANCES ON FRIDAY AND CHANGED THE
CHARACTER TO SLIGHT CHANCES OF THUNDERSTORMS RATHER THAN SHOWERS
ALONE. THE FRONT THAT IS APPROACHING WILL BE PRODUCING DECENT LIFT
SUGGESTING AT LEAST A SLIGHT CHANCE OF THUNDERSTORMS. IT SHOULD BE
NOTED THAT MODELS HAVE BEEN TRENDING WETTER EACH DAY WITH THIS
SYSTEM, BUT WILL HOLD OFF ON RAMPING CHANCES SINCE THE TRAJECTORY
IS NOT THE VERY FAVORABLE FOR SIGNIFICANTLY HIGHER CHANCES AT THIS
TIME. IF THIS SYSTEM TAKES A SLIGHTLY MORE WESTERLY TRACK AS IT
DROPS OUT OF THE PACIFIC NORTHWEST, IT COULD TAP A LITTLE MORE
PACIFIC MOISTURE.

TO WRAP UP THE SHORT TERM FORECAST, FREEZING TEMPERATURES IN THE
SIERRA NEED TO BE MENTIONED. THE COLDEST NIGHTS WILL BE THURSDAY
INTO THE WEEKEND WITH MID TO UPPER 20S POSSIBLE FOR COLDEST SIERRA
VALLEYS. THIS HAS IMPLICATIONS FOR OUTDOOR PETS AND ANY GARDENS WITH
THERMALLY INTOLERANT PLANTS. WHILE COLDER WESTERN NEVADA VALLEYS
WILL BE MAINLY IN THE MID 30S, FROST WILL BE POSSIBLE. THERE ARE
STILL QUESTIONS OF HOW MUCH CLOUD COVER WILL BE PRESENT, BUT ALONG
THE SIERRA FRONT CLOUDS WILL BE LESS THAN MORE NEVADA INTERIOR
LOCALES. BOYD

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

MODELS CONTINUE TO TREND COLDER AS THEY BRING UPPER LOW FARTHER WEST
AND SOUTH INTO THE NORTHERN SIERRA AND WESTERN NV SATURDAY. THE
ECMWF WAS THE DRIEST MODEL WITH SOME LIGHT QPF CONFINED MAINLY NEAR
THE OREGON BORDER. HOWEVER, GIVEN TRENDS THE PAST FEW NIGHTS, WE
NUDGED TEMPERATURES AND SHOWERS TOWARD THE GFS SATURDAY AS IT HAS
SUPPORT FROM ITS ENSEMBLE SUITE AS WELL AS THE GEM RUN. WE EXTENDED
SHOWERS AS FAR SOUTH AS HIGHWAY 50, ALTHOUGH THE BEST CHANCES WILL
BE NORTH OF I-80. TEMPERATURES WILL BE QUITE COOL SATURDAY WITH A
COLD NIGHT IN STORE SATURDAY NIGHT. A FREEZE AND/OR FROST IS IN
STORE FOR SIERRA VALLEYS AND POSSIBLY SOME OF THE COLDER OUTLYING
VALLEYS IN WESTERN NV. THIS WILL BE A CONCERN FOR HIKERS AS WELL
AS THOSE CAMPING ON THE PLAYA IN BLACK ROCK CITY. WITH COLDER
TEMPERATURES AND THE POTENTIAL FOR SOME RAIN, THERE COULD BE THE
POTENTIAL FOR HYPOTHERMIA AND SEVERELY DEGRADED TRAVEL CONDITIONS
IN THE BLACK ROCK DESERT.

DRY CONDITIONS WILL PREVAIL SUNDAY THROUGH TUESDAY WITH TEMPERATURES
REBOUNDING QUICKLY WITH 70S SIERRA AND 80S WESTERN NV BY LABOR DAY
AND TUESDAY. THERE ARE SOME INDICATIONS OF A WEAK TROUGH DEVELOPING
OFF THE CA COAST WHICH COULD BRING BACK INSTABILITY TO THE SIERRA BY
THE MIDDLE OF NEXT WEEK. HOWEVER, MODEL CONFIDENCE IS LOW. HOHMANN

&&

.AVIATION...

INCREASING WINDS WILL LEAD TO LEE SIDE TURBULENCE AND AREAS OF
BLOWING DUST ACROSS WESTERN NV. 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.

A TROUGH WILL CONTINUE TO BRING GUSTY AFTERNOON WINDS THU-FRI WITH
GUSTS 25-30KT. AS UPPER LOW DROPS FARTHER SOUTHWARD, THERE WILL BE
ENOUGH MOISTURE AND INSTABILITY FOR A SLIGHT CHANCE OF THUNDERSTORMS
ACROSS FAR NORTHEAST CA AND NORTHWEST NV ON FRIDAY (GENERALLY NORTH
OF A SUSANVILLE TO GERLACH LINE). SHOWERS MAY WORK THERE WAY AS FAR
SOUTH AS HIGHWAY 50 SATURDAY AS UPPER TROUGH SWINGS THROUGH THE
NORTHERN GREAT BASIN.

&&

.FIRE WEATHER...

NO BIG CHANGE IN THINKING FOR WINDS AND HUMIDITY THIS 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 PERCENT.

AS MENTIONED TUESDAY AFTERNOON, CONDITIONS FOR THE TAHOE BASIN WOULD
BE CLOSE. AFTER ASSESSING LATEST MODEL DATA AND HUMIDITY TRENDS ON
RIDGES ACROSS THE TAHOE BASIN, THE AIRMASS WILL BE A BIT DRIER AND
PUSH MUCH OF THE TAHOE BASIN INTO CRITICAL THRESHOLDS THIS
AFTERNOON. SO WE ARE EXPANDING THE RED FLAG WARNING TO INCLUDE THE
TAHOE BASIN.

FOR TONIGHT, 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
CONTINUES 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 HUMIDITY IS EXPECTED TO
REMAIN MOSTLY OUTSIDE CRITICAL THRESHOLDS.  SNYDER/HOHMANN

&&


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

     BLOWING DUST ADVISORY FROM 1 PM THIS AFTERNOON TO 9 PM PDT THIS
     EVENING NVZ004-005.

     LAKE WIND ADVISORY FROM 11 AM THIS MORNING TO 9 PM PDT THIS
     EVENING FOR LAKE TAHOE IN NVZ002.

     LAKE WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 9 PM PDT THIS
     EVENING FOR PYRAMID LAKE IN NVZ004.

CA...RED FLAG WARNING FROM 1 PM THIS AFTERNOON TO 9 PM PDT THIS
     EVENING CAZ278.

     LAKE WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 9 PM PDT THIS
     EVENING CAZ071.

     RED FLAG WARNING FROM 11 AM THIS MORNING TO 7 PM PDT THIS
     EVENING CAZ272.

     LAKE WIND ADVISORY FROM 11 AM THIS MORNING TO 9 PM PDT THIS
     EVENING 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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