Area Forecast Discussion
Issued by NWS Reno, NV

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000
FXUS65 KREV 030828
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
128 AM PDT SUN MAY 3 2015

.SYNOPSIS...

WARM TEMPERATURES WITH CHANCES FOR ISOLATED SHOWERS AND STORMS WILL
CONTINUE TODAY AND INTO EARLY NEXT WEEK. A LOW PRESSURE SYSTEM
DROPPING OUT OF THE GULF OF ALASKA WILL PROVIDE THE POTENTIAL FOR AN
UNSETTLED AND COOLER WEATHER PATTERN BY MIDWEEK.

&&

.SHORT TERM...

WEAK TROUGHING ACROSS THE EASTERN PACIFIC PERSISTS TODAY AND WILL
PROVIDE WARM CONDITIONS WITH A CHANCE FOR SHOWERS AND THUNDERSTORMS
MAINLY ACROSS SOUTHERN LYON COUNTY INTO MONO AND MINERAL COUNTIES.
CHANCES ARE LESS EXTENDING NORTHWARD WHERE INSTABILITY IS WEAKER AND
SOUTHWESTERLY FLOW HAS BEEN STRONG ENOUGH TO TRANSPORT CUMULUS
DEVELOPMENT OFF THE SIERRA BEFORE SHOWERS AND STORMS HAVE BEEN ABLE
TO MATERIALIZE. THE EXCEPTION MAY BE ACROSS NORTHERN LASSEN COUNTY
WHERE CONVERGENCE MAY POP AN ISOLATED SHOWER OR STORM BY LATE
AFTERNOON. THIS AREA STRUGGLED TO PRODUCE ONLY A FEW WEAK RADAR
RETURNS SO INTRODUCED CHANCES FOR ISOLATED THUNDER LATER IN THE
AFTERNOON.

BY MONDAY THE UPPER LEVEL PATTERN BEGINS TO BECOME MORE PROGRESSIVE
AS A CLOSED LOW OVER THE GULF OF ALASKA HELPS PUSH THE STALLED TROUGH
ACROSS THE WEST COAST. THIS SHOULD ADD SOME INSTABILITY AND
DEFORMATION FORCING WHICH WILL INCREASE CHANCES AND COVERAGE FOR
SHOWERS AND STORMS. BEST CHANCES TO SEE THUNDERSTORMS WILL AGAIN
REMAIN SOUTH OF HWY 50 THROUGH ALPINE AND MONO COUNTIES. THIS
ACTIVITY WILL THEN SPREAD EASTWARD ACROSS SOUTHERN LYON AND
MINERAL COUNTIES BY THE AFTERNOON. ANY CELLS THAT DO FORM WILL BE
CAPABLE OF PRODUCING ABUNDANT SMALL HAIL, LIGHTNING, AND GUSTY
OUTFLOW WINDS.

THE MAIN CLOSED LOW DROPPING FROM THE GULF OF ALASKA WILL THEN NEAR
THE PACIFIC NORTHWEST BY TUESDAY WHICH WILL KICK THE WEAK TROUGH OUT
OF THE REGION BUT WILL MAINTAIN ENOUGH RESIDUAL MOISTURE AND
INSTABILITY TO CONTINUE ISOLATED SHOWERS AND STORMS MAINLY ACROSS
MONO AND MINERAL COUNTIES. MORE NOTABLE REGION WIDE WILL BE AN
INCREASE IN WEST TO NORTHWEST WINDS WITH GUSTS REACHING AROUND 30-35
MPH. OTHERWISE, TEMPERATURES WILL REMAIN ABOVE AVERAGE THROUGH
TUESDAY WITH UPPER 70S TO NEAR 80 ACROSS WESTERN NEVADA AND MID 60S
TO NEAR 70 ACROSS SIERRA VALLEYS. FUENTES


.LONG TERM...WEDNESDAY THROUGH SUNDAY...

MODELS REMAIN IN GOOD AGREEMENT FOR MUCH COOLER AND WETTER
CONDITIONS FOR THE LATTER PART OF NEXT WEEK. NO BIG CHANGES WERE
MADE TO THE OVERALL FORECAST AS THE COOLER/WETTER TRENDS WERE WELL
REPRESENTED.

MAIN CONTRIBUTOR TO THE CHANGES IN THE PATTERN WILL BE A TROUGH
DROPPING OUT OF THE PACIFIC NORTHWEST ACROSS CALIFORNIA AND NEVADA
WEDNESDAY THROUGH FRIDAY. THIS TROUGH WILL REMAIN ACROSS THE REGION
THROUGH FRIDAY BEFORE IT EXITS ACROSS UTAH ON SATURDAY. COOLER AIR
ALOFT WITH THIS TROUGH ALONG WITH SUFFICIENT MOISTURE WILL BE ENOUGH
TO PRODUCE SHOWERS/THUNDERSTORMS EACH DAY ACROSS THE SIERRA AND
WESTERN NEVADA. A COUPLE OF FORECAST MODEL SOLUTIONS ARE SHOWING THE
POTENTIAL FOR A BAND TO SET UP WITH THE TROUGH DROPPING ACROSS THE
REGION ON THURSDAY AND FRIDAY, BUT DIFFERENCES MAKE IT DIFFICULT TO
PINPOINT THE BEST CHANCES FOR PRECIPITATION AT THIS TIME. OVERALL,
IT IS LOOKING LIKE A MUCH WETTER PATTERN FOR NEXT WEEK.

ANOTHER EFFECT OF THE TROUGH ACROSS THE REGION WILL BE THE MUCH
COOLER TEMPERATURES. HIGH TEMPERATURES MAY FALL INTO THE UPPER 40S
AND 50S IN THE SIERRA, WITH 50S TO LOW 60S FOR WESTERN NEVADA
VALLEYS. THE COOLER TEMPERATURES MAY RESULT IN SNOW AND/OR PELLET
ACCUMULATIONS ACROSS THE HIGHER SIERRA AND THE SIERRA PASSES. THOSE
WITH TRAVEL OR OUTDOOR PLANS IN THE SIERRA NEXT WEEK SHOULD CHECK
BACK FOR THE CURRENT WEATHER FORECAST AS IT MAY CHANGE FROM
DAY-TO-DAY.

BY SATURDAY/SUNDAY, MODEL SOLUTIONS ARE SHOWING A GRADUAL WARMUP AS
ZONAL FLOW ATTEMPTS TO SET UP ACROSS THE WEST. THE GFS IS SHOWING
WEAK RIDGING ACROSS THE REGION AS ANOTHER PACIFIC TROUGH ADVANCES
TOWARDS THE WEST COAST, BUT THE ECMWF DOESN`T SHOW THIS FEATURE.
FORECASTER CONFIDENCE IS LOW BEYOND FRIDAY NEXT WEEK. WEISHAHN

&&

.AVIATION...
ISOLATED THUNDERSTORMS ARE POSSIBLE THROUGH 04Z THIS
AFTERNOON/EVENING WITH THE BEST CHANCES SOUTH OF HIGHWAY 50. THESE
STORMS MAY PRODUCE MODERATE RAIN, SMALL HAIL AND GUSTY OUTFLOW WINDS
TO 35 KTS. SOME ISOLATED SHOWERS MAY PERSIST OVERNIGHT MAINLY SOUTH
OF HIGHWAY 50.

KTVL AND KMMH HAVE THE HIGHER PROBABILITY OF BEING AFFECTED BY A
THUNDERSTORM AND/OR SHOWERS. OTHERWISE, NEXT BEST CHANCES FOR
IMPACTS FROM THUNDERSTORMS WILL BE AT KNFL AND KLOL. WITH WEST WINDS
SETTING UP IN THE AFTERNOON, KRNO AND KTRK HAVE LOWER PROBABILITIES
OF THUNDERSTORMS IN THEIR VICINITY. WEISHAHN

&&


.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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