Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 201503 AAA
AFDREV

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RENO NV
803 AM PDT SAT SEP 20 2014

.UPDATE...
MADE A QUICK UPDATE TO THE FORECAST FOR THIS AFTERNOON. WE PULLED
IN SOME ISOLATED SHOWERS AND THUNDERSTORMS A BIT FURTHER NORTH
INTO RENO AND UP TO PYRAMID LAKE, AS WELL AS INCREASING COVERAGE
TO SCATTERED SHOWERS AND THUNDERSTORMS FOR AREAS EAST OF HIGHWAY
95 IN PERSHING AND CHURCHILL COUNTIES. OTHERWISE, SOLID RAIN
AMOUNTS LOOKING GOOD FOR TONIGHT THROUGH SUNDAY FOR MUCH OF THE
EASTERN SIERRA AND WESTERN NEVADA AS THE DEFORMATION ZONE FROM THE
LOW MOVING THROUGH GREAT BASIN. HOON

&&

.PREVIOUS DISCUSSION... /ISSUED 253 AM PDT SAT SEP 20 2014/

SYNOPSIS...

LOW PRESSURE MOVING NORTHEAST ACROSS CALIFORNIA AND NEVADA THIS
WEEKEND WILL PRODUCE SHOWERS AND THUNDERSTORMS LATER TODAY, WITH
THE BEST CHANCES FOR RAIN TONIGHT THROUGH SUNDAY AFTERNOON. WARMER
AND DRIER CONDITIONS ARE EXPECTED MONDAY AND TUESDAY, THEN A
STRONGER LOW PRESSURE WILL BRING INCREASING WINDS, FOLLOWED BY A
COOLING TREND WITH POSSIBLE RAIN LATER IN THE WEEK.

SHORT TERM...

UPPER LOW OFF THE SOUTHERN CA COAST WILL EJECT INLAND ACROSS THE
SAN JOAQUIN VALLEY LATER TODAY, THEN CONTINUE TRACKING NORTHEAST
ACROSS CENTRAL NV ON SUNDAY. SHORT TERM GUIDANCE IS IN REASONABLY
GOOD AGREEMENT FOR THIS SCENARIO, WHICH WOULD LEAD TO DEVELOPMENT
OF ISOLATED TO SCATTERED CONVECTION MAINLY NEAR THE SIERRA AND IN
WEST CENTRAL NV FROM HIGHWAY 95 EASTWARD THIS AFTERNOON.

THE MAIN IMPACT OF THIS LOW WILL BE NOTICED TONIGHT AND SUNDAY AS
VERY MOIST AIR MASS IS PULLED IN FROM THE SOUTHWEST US. PRECIPITABLE
WATER VALUES INCREASE TO NEAR 1 INCH ACROSS MUCH OF WESTERN NV THIS
EVENING AND CONTINUE NEAR THOSE VALUES THRU MOST OF SUNDAY. FORCING
WILL ALSO BECOME STRONGER WITH DEFORMATION ZONE AHEAD OF THE UPPER
LOW TRACK, WHILE COLD POOL ALOFT WILL PROVIDE INSTABILITY FOR
GENERATING AND SUSTAINING SOME CONVECTION EVEN DURING THE
OVERNIGHT AND MORNING HOURS. THE GENERAL CONSENSUS FOR BEST RAIN
CHANCE IS FOR PERSHING AND CHURCHILL COUNTIES WITH POSSIBLE
RAINFALL TOTALS BETWEEN 0.50 AND 1 INCH, SO WE HAVE INCREASED
POPS THE MOST IN THOSE AREAS.

OTHER PARTS OF WESTERN NV AND EASTERN CA, ESPECIALLY SOUTH OF
SUSANVILLE AND INTO THE RENO-TAHOE VICINITY COULD RECEIVE SOME
DECENT RAINFALL IN THE 0.10 TO 0.25 INCH RANGE WITH LOCALLY HIGHER
AMOUNTS LATER TONIGHT THROUGH SUNDAY. THIS WILL BE HIGHLY
DEPENDENT ON LOCATION AND DURATION OF THE MOISTURE BAND AS IT
WRAPS AROUND THE UPPER LOW MOVING ACROSS NEVADA.

WIDESPREAD CLOUD COVER AND ONGOING AREAS OF RAIN IN THE MORNING,
FOLLOWED BY ADDITIONAL CONVECTION IN THE AFTERNOON WILL LIMIT
TEMPERATURE RISES ON SUNDAY. HIGHS HAVE BEEN LOWERED TO THE MID TO
UPPER 70S FOR MOST OF WESTERN NV, ALTHOUGH SOME LOCATIONS COULD
END UP WITH A PERSISTENT BAND OF RAIN AND END UP 5-10 DEGREES
COOLER.

FOR SUNDAY NIGHT, PRECIP WILL DECREASE QUICKLY DURING THE EVENING
AS THE LOW ACCELERATES TO THE NORTHEAST AND EXITS NORTHEAST NV BY
MIDNIGHT. FOR MONDAY, SHORTWAVE RIDGE MOVES ACROSS THE REGION,
BRINGING DRY CONDITIONS AND WARMER TEMPS WITH HIGHS WELL INTO THE
80S FOR MOST WESTERN NV VALLEYS.

WHILE THE KING FIRE WILL CONTINUE TO BURN THRU THIS WEEKEND, THE
PRIMARILY EAST LOW-MID LEVEL FLOW SHOULD KEEP SMOKE WEST OF THE
SIERRA TODAY AND SUNDAY. SOUTHWEST FLOW ALOFT RETURNS MONDAY AND
DEPENDING ON HOW ACTIVE THE FIRE IS BURNING, SMOKE AND HAZE MAY
RETURN TO AREAS AFFECTED EARLIER IN THE WEEK, INCLUDING THE RENO
AND TRUCKEE VICINITY. MJD

LONG TERM...TUESDAY THROUGH FRIDAY...

THE MODELS ARE IN DECENT AGREEMENT THIS MORNING WITH THE SLOW
MOVEMENT OF THE TROUGH ONSHORE NEXT WEEK. THERE IS STILL A GREAT
DEAL OF UNCERTAINTY IN THE DETAILS, ESPECIALLY WHEN LOOKING AT THE
EC ENSEMBLE SPREAD AND STANDARD DEVIATION. HOWEVER, THE MEANS FROM
BOTH THE GFS/EC SUPPORT THE GENERAL IDEA OF THE TROUGH SPLITTING AS
IT MOVES ONSHORE WITH A POTENTIAL CLOSED LOW MOVING THROUGH AS THE
GFS/EC DETERMINISTIC RUNS SHOW. SINCE THE FORECAST IN GENERAL
CONVEYS THIS IDEA, ONLY MADE A FEW MINOR CHANGES.

TUESDAY LOOKS TO BE THE WARMEST DAY OF THE WEEK AS THE SHORT WAVE
RIDGE MOVES TO THE EAST AND A MILD SOUTHWEST FLOW IS EXPECTED
AHEAD OF THE TROUGH. WINDS WILL INCREASE FURTHER WEDNESDAY WITH
POSSIBLE GUSTS TO 45 MPH AS 700 MB WINDS INCREASE TO 30-40 KTS.
ONE CHANGE WAS TO REMOVE ANY SHOWERS FROM WEDNESDAY AS THE LEADING
EDGE OF THE PRECIP WILL JUST BE MOVING ONSHORE AT THIS TIME PER
ENSEMBLE IDEAS.

WINDS WILL STAY UP WEDNESDAY NIGHT AS THE COLD FRONT APPROACHES WITH
THE MAIN COLD FRONT MOVING THROUGH ANY TIME FROM THURSDAY AFTERNOON
THROUGH FRIDAY MORNING. WINDS WILL REMAIN STRONG AND GUSTY AHEAD OF
THE FRONT AND BECOME MORE WEST AND SLACKEN BEHIND IT. AS FAR AS
PRECIP, THE FRONT WILL BE SHEARING AS IT MOVES THROUGH SO ONLY
EXPECT A FEW SHOWERS. THE UPPER LOW MAY MOVE THROUGH FRIDAY OR
SATURDAY, BUT THE COLD AIR LOOKS TO BE IN PLACE. SHOWERS WILL
CONTINUE WITH THE BEST CHANCE NORTH OF I-80. TEMPERATURES SHOULD BE
MUCH COOLER, DROPPING AS MUCH AS 10 DEGREES BELOW AVERAGE FOR
FRIDAY. WALLMANN

AVIATION...

EXPECT HAZE TO CONTINUE DIMINISHING TODAY WITH SHOWERS AND
THUNDERSTORMS THE MAIN THREAT THIS WEEKEND AS UPPER LOW MOVES
ACROSS CA-NV. EXPECT AREAS OF MVFR CIGS/VIS AND ISOLATED
THUNDERSTORMS BEGINNING AFTER 22Z TODAY. THE HIGHEST THREAT WILL
BE EAST OF 395 AND SOUTH OF I-80 TONIGHT. THIS WILL SHIFT NORTH
DURING THE DAY SUNDAY. PROBABILITY OF MVFR CIGS/VIS AT MAIN
TERMINALS ABOUT 20 PCT FOR KRNO/KCXP AND 10-15 PCT AT
KMMH/KTVL/KTRK WITH THE EAST FLOW. SOME MTN OBSCN LIKELY 00-18Z
SUNDAY IN THE BANDS OF SHOWERS. WALLMANN

&&

.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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