Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 240301 AAA
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
800 PM PDT SAT AUG 23 2014

.UPDATE...
NO UPDATES REQUIRED THIS EVENING TO THE SHORT TERM FORECAST. SKIES
ARE EXPECTED TO CLEAR OVERNIGHT WITH LIGHT E/NE WINDS. PROBABLY THE
ITEM OF MOST INTEREST IS SHORTWAVE DIVING INTO THE REGION MONDAY.
LATEST GUIDANCE STILL DEPICTS A SHARP WAVE WITH PLENTIFUL ASCENT
COUPLED WITH INSTABILITY - PRODUCING ISOLATED SHOWERS AND TSTMS
MONDAY AFTERNOON. CS


&&


.SYNOPSIS...
COOLER TEMPERATURES WITH LIGHT WINDS WILL CONTINUE INTO EARLY
NEXT WEEK. ON MONDAY THERE IS A SLIGHT CHANCE FOR THUNDERSTORMS
ACROSS NORTHEAST CALIFORNIA AND NORTHERN NEVADA. A WARMING TREND
IS EXPECTED BEGINNING TUESDAY WITH HIGH PRESSURE BUILDING OVER THE
WEST.

&&

.SHORT TERM...
SIERRA VALLEYS WERE COLD LAST NIGHT WITH MOST COMMUNITIES COOLING
INTO THE 30S AND SOME TO THE UPPER 20S. CLEAR SKIES, LIGHT WIND
AND SIMILAR COOL TEMPERATURES ARE FORECAST AGAIN TONIGHT FOR
SIERRA VALLEY LOCATIONS. SUNDAY THE FLOW ALOFT WILL TRANSITION
FROM NORTHWESTERLY TO WESTERLY AS A TROUGH BEGINS TO MOVE SOUTH
OUT OF THE PACIFIC NORTHWEST. SURFACE WINDS, WHICH ARE GENERALLY
NORTHERLY-TO-EASTERLY TODAY, WILL ALSO SHIFT BACK TO WESTERLY
SUNDAY AFTERNOON BUT WILL BE RELATIVELY LIGHT WITH GUSTS MOSTLY
BELOW 20 MPH.

FOR SUN NIGHT-MONDAY, COMPUTER GUIDANCE HAS TRENDED FARTHER WEST
WITH THE TROUGH DIGGING SOUTH OUT OF THE PACIFIC NORTHWEST. THE
NEW CONSENSUS IS FOR A SHORTWAVE TO MOVE SOUTH INTO THE NORTHWEST
CORNER OF CALIFORNIA AND NORTHERN NV LATE SUNDAY NIGHT. THE
MORNING RUNS OF THE GFS AND ECMWF MODELS SHOW LIGHT PRECIPITATION
AND WEAK INSTABILITY WITH THIS FEATURE, MAINLY ACROSS NEVADA NORTH OF
I-80. CONFIDENCE IS LOW IN THE TRACK OF THIS FEATURE, BUT FOR NOW
A SLIGHT CHANCE FOR THUNDERSTORMS WAS INTRODUCED FOR NORTHERN
WASHOE VALLEY SUNDAY NIGHT, SPREADING TO THE SURPRISE VALLEY AND
NORTHERN LASSEN AND PERSHING COUNTIES ON MONDAY.

MONDAY NIGHT THE TROUGH IS EXPECTED TO SHIFT EASTWARD BRINGING A
DRY NORTHWEST FLOW ACROSS THE EASTERN SIERRA AND WESTERN NV. JCM

.LONG TERM...TUESDAY THROUGH SATURDAY...
OPERATIONAL MODELS LOOK SIMILAR TO PREVIOUS RUNS FOR NOW, SO
SMALL CHANGES WERE MADE TO THE ONGOING LONG TERM FORECAST. MAIN
GAME CHANGER IN THE LONG TERM CONTINUES TO ENTAIL A COUPLE OF
FEATURES. FIRST, HOW STRONGLY THE RIDGE ANCHORS ITSELF ACROSS THE
WEST AND SECOND, HOW REMNANTS OF HURRICANE MARIE MAY TRACK
NORTHWARD THROUGH THE NEXT FEW DAYS.

HIGH CONFIDENCE FOR A WARMING TREND TO OCCUR AS THE RIDGE
STRENGTHENS ACROSS THE REGION STARTING ON TUESDAY. ABOVE NORMAL
HIGHS AND LOWS ARE EXPECTED EACH DAY ALONG WITH LIGHT WINDS AND
RELATIVELY LIGHT WINDS. BY LATE THURSDAY, MODEL SOLUTIONS DIVERGE
AS THE GFS FLATTENS THE RIDGE IN RESPONSE TO A LARGE TROUGH DROPPING
OUT OF THE GULF OF ALASKA, WHILE THE ECMWF RIDGE ONLY FLATTENS
SLIGHTLY AND MAINTAINS A FAR LESS AMPLIFIED ALASKAN TROUGH FOR LATE
NEXT WEEK.

WITH RESPECT TO THE REMNANTS OF HURRICANE MARIA, THE GFS CONTINUES
TO SHOW THE POTENTIAL FOR THE TROPICAL MOISTURE TO GET WRAPPED UP
INTO THE ALASKAN TROUGH DROPPING INTO THE WEST COAST FOR FRIDAY AND
SATURDAY. THE ECMWF KEEPS THE REMNANTS WELL WEST OFF OF THE
CALIFORNIA COAST, AND WITH A LACK OF THE STRONG TROUGH THAT THE GFS
SHOWS, THERE WOULD BE LITTLE TO NO CHANCE FOR THAT MOISTURE TO
ADVECT EASTWARD. ALL THINGS CONSIDERED, THERE CONTINUES TO BE LOW
CONFIDENCE BEYOND FRIDAY FOR THE LONG TERM FORECAST WITH ONLY
INCREASING CLOUDINESS FOR THE NORTHERN PORTIONS OF THE SIERRA AND
WESTERN NEVADA EXPECTED FOR NOW. ELW

&&

.AVIATION...
LIGHT NORTHEAST LOW LVL WINDS TODAY FOR ALL TERMINALS. NEAR THE
SIERRA CREST...WINDS ARE LIKELY TO BE VARIABLE TODAY BUT STRENGTHEN
OVERNIGHT FROM THE EAST.

VFR CONDITIONS THROUGH THE NEXT FEW DAYS WITH CONTINUED LIGHT WINDS.
THE WINDS SHIFT AROUND TO THE WEST LATE SUNDAY...BUT REMAIN LESS
THAN 15 KTS MOST AREAS. 20/ELW

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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






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