Area Forecast Discussion
Issued by NWS Reno, NV

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000
FXUS65 KREV 271139
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
254 AM PST TUE JAN 27 2015

.SYNOPSIS...

A LOW PRESSURE SYSTEM WILL PUSH NORTH INTO THE SIERRA AND WESTERN
NEVADA AND BRING PERIODS OF LIGHT VALLEY RAIN AND MOUNTAIN SNOW
SHOWERS TODAY. TEMPERATURES WILL COOL OFF THROUGH THE END
OF THE WEEK, WITH A FEW SHOWERS AGAIN POSSIBLE SOUTH OF HIGHWAY 50
THURSDAY AND FRIDAY. DRIER CONDITIONS RETURN FOR THE WEEKEND INTO
NEXT WEEK.

&&

.SHORT TERM...

ONLY MINOR ADJUSTMENTS WERE MADE TO THE EXISTING FORECAST WITH THE
PRIMARY CHANGE BEING A SLOWER ONSET OF PRECIPITATION FOR
LOCATIONS NORTH OF HIGHWAY 50. RAIN AND HIGH ELEVATION SNOW ARE
SLOWLY MOVING INTO WESTERN NEVADA AND NORTHEASTERN CALIFORNIA AS LOW
PRESSURE TRACKS NORTHWARD OUT OF BAJA CALIFORNIA.

MODELS CONTINUE TO INCREASE MOISTURE THROUGH THE MORNING INTO THE
AFTERNOON TODAY AS THE OVERALL FORCING FOR PRECIPITATION WEAKENS.
THE GENERAL CHARACTERISTIC OF THIS SYSTEM WILL BE HIGHER
PROBABILITY OF PRECIPITATION, BUT LOW TOTALS. WHILE PRECIPITATION
WILL BE FAIRLY WIDESPREAD TODAY, LIQUID EQUIVALENTS WILL BE RATHER
MEAGER WITH THE HIGHER TOTALS FAVORING UPSLOPE AREAS ALONG SOUTHERN
AND EASTERN SLOPES. STILL, ONLY UP TO 0.25 INCH OF LIQUID ARE
EXPECTED ALONG THESE FAVORED AREAS. ISOLATED TOTALS UP TO 0.33
INCH WILL BE POSSIBLE ALONG THE HIGHEST TERRAIN OF THE SIERRA
CREST MAINLY IN MONO COUNTY TO THE SOUTHERN REACHES OF THE TAHOE
BASIN. VALLEY LOCATIONS, ESPECIALLY THOSE IN WESTERN NEVADA, WILL BE
LIMITED TO LESS THAN 0.1 INCH WITH MOST LOCATIONS RECEIVING ONLY A
FEW HUNDREDTHS.

SNOW LEVELS WILL LOWER TO AROUND LAKE TAHOE LEVEL. SNOW
ACCUMULATIONS WILL BE GENERALLY LESS THAN AN INCH FROM AROUND LAKE
LEVEL UP TO 7000 FEET WITH A COUPLE TO 4 INCHES OF SLUSHY
ACCUMULATION POSSIBLE ABOVE 7000 FEET.

BY EARLY AFTERNOON, FORCING DRASTICALLY WEAKENS WITH THE UPPER CLOSED
LOW OPENING AS IT LOSES JET SUPPORT. A BRIEF, WEAK RIDGE WILL QUICKLY
TRANSIT THE REGION WEDNESDAY WITH TEMPERATURES REMAINING COOLER
THAN IT HAS BEEN UNDER MOSTLY CLOUDY SKIES. HIGHS IN WESTERN
NEVADA VALLEYS WILL REMAIN IN THE LOW/MID 50S WHILE DIPPING INTO
THE MID 40S FOR SIERRA VALLEYS. BY THURSDAY, A WEAKLY SUPPORTED UPPER
TROUGH SETTLES OVER THE WEST COAST. THE MAIN EFFECT WILL BE AN
INCREASE IN CLOUDS WITH A SOME SLIGHT CHANCES OF RAIN/SNOW SOUTH
OF HIGHWAY 50. BOYD

.LONG TERM...FRIDAY THROUGH MONDAY...

NO SIGNIFICANT CHANGES WERE MADE TO THE CURRENT FORECAST. OVERALL
THE POTENTIAL FOR LIGHT SHOWERS SOUTH OF HIGHWAY 50 FRIDAY AND
FRIDAY NIGHT APPEARS TO BE DECREASING, AS THE ECMWF HAS REDUCED
PRECIP AMOUNTS COMPARED TO PREVIOUS RUNS WHILE THE GFS REMAINS DRY.
LOW-END SLIGHT CHANCES WERE RETAINED FOR NOW, BUT THEY MAY REMOVED
IF THE ECMWF CONTINUES THIS DRIER TREND ON ITS NEXT RUN.

FOR THIS WEEKEND, RIDGE OFF THE WEST COAST REBUILDS INLAND ACROSS
NORTHERN CALIFORNIA SATURDAY AND THEN PUSHES SOUTH SUNDAY, RESULTING
IN DRY CONDITIONS REGION-WIDE. TEMPERATURES WILL WARM UP FIRST IN
THE HIGHER ELEVATIONS SATURDAY, THEN ACROSS ALL AREAS SUNDAY. HIGHS
ON SUNDAY ARE EXPECTED TO RANGE FROM THE MID TO UPPER 50S FOR LOWER
ELEVATIONS AND SIERRA VALLEYS, WITH 40S IN THE MOUNTAINS. GUSTY EAST
WINDS ARE LIKELY TO DEVELOP ACROSS HIGHER ELEVATIONS BETWEEN THE
BUILDING RIDGE AND EXITING LOW FRIDAY NIGHT INTO SATURDAY, WITH
POSSIBLE RIDGE GUSTS OF 60 TO 80 MPH.

BY EARLY NEXT WEEK, THE RIDGE APPEARS MORE LIKELY TO FLATTEN ACROSS
NORTHERN CALIFORNIA WITH A PLUME OF MOISTURE MOVING INTO THE PACIFIC
NORTHWEST SUNDAY NIGHT INTO MONDAY. AT THIS TIME IT APPEARS THAT
THE MAIN EFFECT WILL BE INCREASED MID AND HIGH LEVEL CLOUDS, BUT
PRECIPITATION IS UNLIKELY TO REACH NORTHEAST CALIFORNIA. THIS WILL
ALSO WEAKEN THE INVERSION SO WHILE LOWER ELEVATIONS WILL REMAIN MILD
ON MONDAY, SOME COOLING IS EXPECTED FOR THE HIGHER ELEVATIONS AND
THE SIERRA VALLEYS. MJD

&&

.AVIATION...

AS LOW PRESSURE LIFTS NORTH THROUGH NEVADA, IT WILL BRING AREAS OF
LIGHT RAIN AND SNOW ACROSS MOST OF THE REGION TODAY, ESPECIALLY IN
AREAS EAST OF A TRUCKEE-GERLACH LINE. WITH SNOW LEVELS AROUND
6000-6500 FEET, A RAIN/SNOW MIX IS POSSIBLE FOR KTRK, KTVL, AND
KMMH, BUT RUNWAY ACCUMULATION IS UNLIKELY DUE TO WARM TEMPERATURES
OF PAVED SURFACES. PERIODS OF IFR CIGS/VSBY AND MOUNTAIN OBSCURATION
ARE LIKELY IN THE SIERRA. FOR WESTERN NEVADA, LIGHT RAIN IS EXPECTED
WITH PERIODS OF MVFR CIGS. WINDS WILL GENERALLY BE LIGHT.

WIDESPREAD CLOUD COVER SHOULD LIMIT FOG FORMATION AROUND KTRK
TONIGHT BUT IF MEASURABLE RAINFALL OCCURS TODAY AND CLOUD COVER
THINS OUT LATE TONIGHT, THEN CONDITIONS WOULD BECOME MORE FAVORABLE
FOR REDUCED VSBY EARLY WED MORNING. OTHERWISE, VFR CONDITIONS WITH
LIGHT WINDS ARE EXPECTED ACROSS THE REGION WEDNESDAY, ALTHOUGH SOME
OBSCURATION OF HIGHER PEAKS IN THE SIERRA ARE POSSIBLE WED MORNING.
MJD

&&



.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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