Area Forecast Discussion
Issued by NWS Reno, NV

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000
FXUS65 KREV 232102
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
202 PM PDT WED JUL 23 2014

.SYNOPSIS...
BREEZY WINDS AND CRITICAL FIRE WEATHER CONDITIONS WILL DIMINISH
THIS EVENING AS LOW PRESSURE MOVES INTO THE NORTHERN ROCKIES. HIGH
PRESSURE BUILDING OVER THE SOUTHWEST WILL BRING LIGHT WINDS, DRY
CONDITIONS AND A WARMING TREND INTO THE WEEKEND. THUNDERSTORMS ARE
POSSIBLE EARLY NEXT WEEK AS MOISTURE AND INSTABILITY START TO
INCREASE ON SUNDAY.

&&

.SHORT TERM...

BREEZY WINDS TO 35 MPH WILL CONTINUE THROUGH 9 PM THIS EVENING AS
THE LOW OVER THE PACIFIC NORTHWEST LIFTS INTO THE CANADIAN
ROCKIES. THE RIDGE OVER THE HIGH PLAINS WILL THEN RETROGRADE TO
THE DESERT SOUTHWEST AND AMPLIFY OVER NEVADA ON SATURDAY.

AS THE RIDGE BUILDS OVER NEVADA AFTERNOON HIGHS WILL WARM INTO THE
MID AND UPPER 90S FOR THE LOWER ELEVATIONS WITH 80S FOR THE
SIERRA. A FEW LOCATIONS IN PERSHING AND CHURCHILL COUNTIES MAY
REACH 100 DEGREES BY SATURDAY.

OVERNIGHT LOWS SHOULD COOL QUITE A BIT OVER THE NEXT COUPLE NIGHTS
DUE TO DRIER AIR MOVING INTO THE REGION. THE SIERRA VALLEYS WILL
DROP TO MID 30S TO LOW 40S, WHILE MOST NEVADA VALLEYS COOL INTO
50S. AT THE RENO AIRPORT, THE 24 CONSECUTIVE DAYS OF OVERNIGHT
LOWS GREATER THAN OR EQUAL TO 60 SHOULD END TONIGHT. BRONG

.LONG TERM...SATURDAY THROUGH WEDNESDAY...
ADDED A SLIGHT CHANCE OF THUNDERSTORMS TO AREAS NORTH OF SUSANVILLE
AND GERLACH SUNDAY, OTHERWISE LITTLE CHANGE TO THE LONG TERM
FORECAST.

EASTERN CALIFORNIA AND WESTERN NEVADA WILL REMAIN ON THE WESTERN
PERIPHERY OF AN UPPER RIDGE SATURDAY THROUGH MONDAY. THIS IS
EXPECTED TO ALLOW INSTABILITY AND MOISTURE TO BEGIN BUILDING DUE TO
STRONG HEATING AND EVENTUAL MOISTURE ADVECTION AROUND THE PERIPHERY
OF THE RIDGE EARLY NEXT WEEK. I EXTENDED THE SLIGHT CHANCE OF
THUNDERSTORMS SUNDAY INTO NORTHERN LASSEN AND WASHOE COUNTIES, AS
WELL AS FOR THE SURPRISE VALLEY, AS BOTH THE GFS AND ECMWF SHOW AN
UPPER DISTURBANCE APPROACHING NORTHERN CALIFORNIA WHICH WOULD
INCREASE MOISTURE AND AFTERNOON LOW LEVEL WIND CONVERGENCE THERE.

SOME MODEL DISCREPANCIES START TO POP UP NEXT WEEK WHICH WOULD
AFFECT CONVECTIVE DEVELOPMENT. THE GFS QUICKLY REBUILDS THE UPPER
RIDGE BEHIND SUNDAY`S UPPER DISTURBANCE FOR A CONTINUED THREAT FOR
THUNDERSTORMS EACH AFTERNOON AND EVENING. HOWEVER, THE ECMWF BRINGS
MORE WESTERLY FLOW ALOFT INTO THE SIERRA AND WESTERN NEVADA WHICH
COULD REDUCE INSTABILITY AND FLUSH OUT MOISTURE ENOUGH TO GREATLY
REDUCE OR EVEN ELIMINATE THUNDERSTORMS. AS THE GFS IS CERTAINLY
POSSIBLE AND ENSEMBLES CANNOT RESOLVE THE MODEL DIFFERENCES I HAVE
OPTED TO KEEP THE SLIGHT CHANCE OF THUNDERSTORMS THROUGH THE MIDDLE
OF NEXT WEEK.

TEMPERATURE-WISE, HIGHS ARE EXPECTED TO REMAIN NEAR OR SLIGHTLY
ABOVE AVERAGE THROUGH THE LONG TERM. ONE CAVEAT WILL BE CLOUDS AND
THUNDERSTORM LOCATION WHICH WOULD LIMIT THE POTENTIAL MAXIMUM
TEMPERATURES. AS THIS IS HARD TO PINPOINT THIS FAR OUT, THE CURRENT
FORECAST HIGHS REFLECT THE HIGHER END OF THE SPECTRUM (ASSUMING NO
CONTAMINATION FROM THUNDERSTORMS OR THICK CLOUD COVER). SNYDER

&&

.AVIATION...
DRY AND STABLE WEST-SOUTHWEST FLOW ALOFT WILL PREVAIL THROUGH
THURSDAY FOR NORTHEAST CALIFORNIA AND WESTERN NEVADA AS LOW PRESSURE
MOVES INTO WASHINGTON AND OREGON. AT THE SURFACE, A COLD FRONT
MOVING INTO OREGON AND EXTREME NORTHERN CALIFORNIA IS HELPING TO
BRING ENHANCED WINDS FOR THIS AFTERNOON AND EVENING. WEST-SOUTHWEST
WIND GUSTS TO 25-30 KTS ARE EXPECTED INTO THIS EVENING, ESPECIALLY
NORTH OF INTERSTATE 80. WINDS WILL BE MUCH LIGHTER THURSDAY. SNYDER

&&

.FIRE WEATHER...

...RED FLAG WARNING FOR GUSTY WINDS AND LOW HUMIDITIES IMPACTING
LIGHTNING HOLDOVERS FOR WESTERN NEVADA UNTIL 9 PM THIS EVENING...

RED FLAG WARNING WAS ISSUED EARLIER FOR THIS AFTERNOON/EVENING FOR
WESTERN NEVADA ZONES 450/453/458 FOR WIND GUSTS 30-35 MPH AND LOW
HUMIDITIES IN THE TEENS. TIPPING POINT IN DECIDING TO ISSUE RED FLAG
WAS THE COPIOUS AMOUNT OF LIGHTNING WE`VE HAD THE PAST FEW DAYS WHICH
MAY CONTRIBUTE TO HOLDOVER FIRES DEVELOPING IN THE GUSTY WINDS. BASED
ON RECENT OBSERVATIONS WE WILL CONTINUE THE RED FLAG WARNING AS IS
UNTIL 9 PM EXPIRATION. WINDS MAY REMAIN GUSTY ON THE RIDGES AND MID
SLOPES OVERNIGHT INTO THURS MORNING WITH JET OVERHEAD AND COLD FRONT IN
THE THE VICINITY.

WINDS LIGHTEN UP A BIT FRIDAY/SATURDAY WITH ONLY A WEAK ZEPHYR WIND
EXPECTED IN TAHOE/TRUCKEE AND THE SIERRA FRONT. APPRECIABLE DRYING IS
EXPECTED. HUMIDITY RECOVERIES OVERALL WOULD BE CLASSIFIED AS POOR
FRI/SAT/SUN MORNINGS. A FEW BUILDUPS OVER THE HIGH TERRAIN ARE POSSIBLE
SATURDAY, AND THEN ISOLATED THUNDERSTORMS ARE BACK IN THE FORECAST
SUN/MON/TUES AFTERNOONS AS MOISTURE ALOFT WORKS BACK INTO THE REGION.
UNCERTAINTY REMAINS HIGH REGARDING HOW WIDESPREAD STORMS MAY GET, BUT
IT APPEARS STORM MOTIONS WOULD BE FAST ENOUGH TO POTENTIALLY PRODUCE
DRY LIGHTNING STRIKES. CS

&&

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

     LAKE WIND ADVISORY UNTIL 8 PM PDT THIS EVENING NVZ004.

CA...NONE.
&&

$$

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



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