Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 261034
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
234 AM PST MON JAN 26 2015

.SYNOPSIS...
HIGH PRESSURE OVER THE WEST WILL BRING MILD TEMPERATURES TODAY.
PERIODS OF LIGHT VALLEY RAIN AND MOUNTAIN SNOW SHOWERS ARE
EXPECTED TUESDAY. COOLER TEMPERATURES RETURN TUESDAY THROUGH THE
END OF THE WEEK, WITH A FEW SHOWERS AGAIN POSSIBLE SOUTH OF
HIGHWAY 50 LATE IN THE WEEK.

&&

.SHORT TERM...
FEW CHANGES MADE TO THE SHORT TERM AS THE GOING FORECAST HANDLES
THE CURRENT SITUATION WELL. THE MAIN FEATURE OF INTEREST CONTINUES
TO BE THE UPPER LOW OFF BAJA AT THE MOMENT THAT IS BEGINNING ITS
MOVE NORTHWARD. LIGHT SOUTHWEST FLOW AND WARM TEMPS ALOFT WILL
ALLOW FOR ANOTHER MILD DAY WITH HIGHS 10-15 DEGREES ABOVE AVERAGE.
MID AND HIGH CLOUD COVER WILL SLOWLY INCREASE WHICH WILL LIKELY
KEEP TEMPS SLIGHTLY COOLER THAN YESTERDAY SOUTH OF I-80, BUT SOME
RECORDS STILL POSSIBLE IN THE SIERRA.

TONIGHT, THE LOW MOVES ONSHORE WITH MOISTURE INCREASING SOUTH OF
HIGHWAY 50. LIGHT RAIN/MTN SNOW WILL DEVELOP AFTER MIDNIGHT OVER
MONO/MINERAL COUNTIES WITH THE LOW. THE LIGHT RAIN AND SNOW WILL
CONTINUE TO MOVE NORTHWARD DURING THE DAY TO PERHAPS AS FAR NORTH
AS A PORTOLA TO WINNEMUCCA LINE. THERE, THE MODELS AGREE IN
SHEARING APART THE UPPER LOW AND START A TRANSITION AT MOVING
THE MOISTURE EAST INTO NORTHEAST NEVADA. NORTH OF THAT LINE, ONLY
A FEW SHOWERS ARE POSSIBLE, BUT EVEN THAT SEEMS UNLIKELY. THERE
SHOULD BE A FAIRLY SHARP GRADIENT BETWEEN THE LIGHT RAIN AND
NOTHING AS THE ATMOSPHERE IS STABLE AND THERE IS LIMITED FORCING
NORTH OF THAT LINE.

TOTAL AMOUNTS OF PRECIP WILL AVERAGE AROUND A TENTH OF AN INCH OF
RAIN IN THE VALLEYS WITH A COUPLE INCHES OF SNOW IN THE MOUNTAINS
ABOVE 7000 FEET. WHILE THERE COULD BE SOME SLICK/SLUSHY ROADS
ABOVE 7000 FEET IN THE MORNING, THE INTENSITY AND AFTERNOON SUN
WILL LIKELY LIMIT THE ROADS TO BEING JUST WET BY THAT TIME.

THE SHEARED UPPER LOW WILL THEN MOVE SLOWLY AWAY TUESDAY NIGHT AS
A NEW WEAK LOW FORMS OFF THE CALIFORNIA COAST. THE WEAK FLOW WILL
NOT SCOUR OUT THE MOISTURE, AND EXPECT ABUNDANT CLOUD COVER TO
REMAIN INTO WEDNESDAY. HOWEVER, WITH NO FORCING APPARENT AS THE
NEXT UPPER LOW REMAINS OFF THE COAST, HAVE KEPT THE FORECAST DRY
ALTHOUGH A FEW FLURRIES ARE POSSIBLE IN THE MOUNTAINS. WALLMANN

.LONG TERM...THURSDAY THROUGH SUNDAY...
FOR THURSDAY AND FRIDAY, WEAK BAGGY TROUGH APPROACHES THE
SOUTHERN SIERRA, WITH SMALL DEFORMATION ZONE POSSIBLY SETTING UP
OVER MONO AND MINERAL COUNTIES. THE ECMWF REMAINS MORE AGGRESSIVE
WITH THIS SHOWER POTENTIAL SOUTH OF HIGHWAY 50, BUT THE GFS
INDICATES A DRIER SCENARIO WITH THE TROUGH TRACKING FARTHER SOUTH
ACROSS SOUTHERN CALIFORNIA. FOR NOW WE WILL KEEP THE SLIGHT CHANCE
OF SHOWERS IN PLACE, BUT WITH THE MODEL GUIDANCE SHOWING DIVERGING
SCENARIOS THE CONFIDENCE LEVEL FOR RAIN OR SNOW SHOWERS OCCURRING
IN MONO OR MINERAL COUNTIES IS RATHER LOW. NORTH OF HIGHWAY 50, NO
PRECIPITATION IS EXPECTED THURSDAY AND FRIDAY AS RIDGE AXIS OFF
THE WEST COAST BEGINS TO REBUILD INLAND ALONG THE CALIFORNIA-
OREGON BORDER.

FOR NEXT WEEKEND, MEDIUM RANGE GUIDANCE REMAINS IN GOOD AGREEMENT
WITH RIDGE AXIS EXPANDING SOUTH ACROSS CALIFORNIA AND NEVADA,
PUSHING THE UPPER LOW IN THE SOUTHWEST US FARTHER SOUTH INTO
NORTHERN MEXICO. THIS WILL RESULT IN ANOTHER DRY WEEKEND OVER THE
SIERRA AND WESTERN NEVADA AS FEBRUARY BEGINS.

TEMPERATURES LATER THIS WEEK WILL REMAIN A FEW DEGREES ABOVE
NORMAL, BUT THE PRESENCE OF CLOUD COVER AND/OR LIGHT NORTH TO EAST
SURFACE FLOW WILL LIMIT DAYTIME HEATING. HIGHS GENERALLY IN THE
LOWER TO MID 50S FOR WESTERN NV AND A FEW DEGREES COOLER FOR THE
SIERRA VALLEYS ARE EXPECTED THURSDAY AND FRIDAY. BY NEXT WEEKEND
AS THE RIDGE BUILDS OVERHEAD, WARMING TREND WILL BE NOTICED MORE IN
HIGHER ELEVATIONS SATURDAY, FOLLOWED BY AN ADDITIONAL INCREASE OF
2-5 DEGREES AT ALL ELEVATIONS ON SUNDAY.

NORTHEAST TO EAST RIDGE LEVEL WINDS ARE LIKELY TO INCREASE FRIDAY
NIGHT AND SATURDAY GIVEN THE FORECASTED POSITION OF THE RIDGE AND
UPPER LOW, WITH GUSTS POSSIBLY REACHING 60-80 MPH IN THE SIERRA.
MJD

&&

.AVIATION...
FOR THIS MORNING, IT APPEARS THAT EAST TO SOUTHEAST FLOW
CONTINUING ALONG THE RIDGES COMBINED WITH INCREASING AREA OF
CIRRUS WILL INHIBIT FZFG FORMATION AROUND KTRK. VFR CONDITIONS
WITH GENERALLY LIGHT WINDS AND AREAS OF CIRRUS WILL PREVAIL TODAY
THROUGH THIS EVENING.

BY LATE TONIGHT, LIGHT RAIN AND SNOW IS EXPECTED TO DEVELOP SOUTH
OF HIGHWAY 50 INCLUDING KMMH, THEN SPREAD NORTH ACROSS THE TAHOE
BASIN AND WESTERN NEVADA DURING THE DAY TUESDAY. SNOW LEVELS
VARYING BETWEEN 6000-6500 FEET WILL RESULT IN A MIXTURE OF RAIN
AND SNOW FOR THE SIERRA TERMINALS. WHILE RUNWAYS SHOULD GENERALLY
BE WET, SOME LIGHT SLUSHY ACCUMULATIONS ARE POSSIBLE AT KMMH
BEFORE DAYBREAK. PERIODS OF IFR CIGS/VSBY WITH MOUNTAIN OBSCURATIONS
ARE LIKELY TUESDAY FOR KTVL/KTRK/KMMH, WHILE CIGS COULD DROP TO
MVFR AT TIMES FOR LOWER ELEVATIONS INCLUDING KRNO/KCXP. 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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