Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 211035
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
235 AM PST SUN DEC 21 2014

.SYNOPSIS...

CHANCES FOR RAIN AND SNOW WILL GRADUALLY DIMINISH FROM SOUTH TO
NORTH THROUGH THIS EVENING. DRY CONDITIONS AND MILD TEMPERATURES
ARE ANTICIPATED TODAY THROUGH WEDNESDAY AS HIGH PRESSURE BUILDS
INTO THE REGION. A STRONG COLD FRONT IS POSSIBLE LATE WEDNESDAY
INTO CHRISTMAS DAY WITH GUSTY WINDS, RAIN, AND SNOW.

&&

.SHORT TERM...

ONLY SOME SLIGHT ADJUSTMENTS FOR TODAY`S FORECAST AS SIERRA AND
NORTHWESTERN NEVADA PRECIPITATION CHANCES SLOWLY DIMINISH THROUGH
THE DAY. DID INCREASE CHANCES TO AT LEAST 25% FOR THE SIERRA FROM
I-80 NORTHWARD AS ISENTROPIC LIFT AND MOIST ON-SHORE FLOW CONTINUE
TO SUPPORT SOME VERY LIGHT SNOW AND RAIN MAINLY ALONG HIGHER
TERRAIN. THIS WILL CHANGE AS THE PRESSURE GRADIENT DEFORMS DUE TO
RIDGING BECOMING MORE PRONOUNCED ALONG THE PACIFIC COAST THIS
AFTERNOON AND EVENING TURNING WINDS MORE NORTHERLY. THIS WILL CUT
OFF THE MOIST FLOW ALLOWING FOR DRIER CONDITIONS TONIGHT THROUGH
MID WEEK AS RIDGING STRENGTHENS.

OTHERWISE, THE PRESSURE GRADIENT WILL REMAIN TIGHT INTO THE EARLY
AFTERNOON TODAY ACROSS THE EXTREME NORTHEASTERN CALIFORNIA AND
NORTHWESTERN NEVADA NORTH OF GERLACH. GUSTS HAVE REACHED THE UPPER
40S TO LOW 50 MPH RANGE IN SURPRISE VALLEY AND VERY NORTHERN
WASHOE COUNTY; A WIND ADVISORY REMAINS IN EFFECT THROUGH THE EARLY
AFTERNOON. WINDS DECREASE THIS EVENING AS THE GRADIENT RELAXES.

TEMPERATURES HAVE REMAIN ELEVATED OVERNIGHT FOR MANY LOCATIONS
ALONG THE SIERRA FRONT DUE TO WINDS KEEPING THE LOWER ATMOSPHERE
WELL MIXED. AS A RESULT, SURFACE INVERSIONS HAVE NOT BEEN ABLE TO
FORM LEADING TO WARMER THAN EXPECTED LOWS. THIS HAS LED TO AN
INCREASE IN FORECAST HIGHS FOR TODAY, GENERALLY AROUND 60 DEGREES
FOR WESTERN NEVADA. THERE IS A POSSIBILITY THAT SEVERAL LOCATIONS,
INCLUDING RENO (63 CURRENT RECORD), COULD APPROACH/EXCEED RECORD
HIGH TEMPERATURES. AS MIXING LESSENS OVER THE NEXT COUPLE OF DAYS,
DAILY HIGH TEMPERATURES COOL A FEW DEGREES BY TUESDAY BACK INTO
THE LOW/MID 50S WHICH REMAINS SEASONABLY WARM. BOYD

.LONG TERM...CHRISTMAS EVE THROUGH SUNDAY...

NO SIGNIFICANT CHANGE IN THE MODEL DATA OVER THE LAST 24 HOURS. HIGH
PRESSURE OVER THE WEST WILL BREAK DOWN WEDNESDAY AS A LOW AND COLD
FRONT MOVE INTO THE WEST COAST. THE FRONT SHOULD PUSH INTO LASSEN,
NORTHERN WASHOE AND THE SURPRISE VALLEY WEDNESDAY AFTERNOON THEN
QUICKLY TRACK SOUTH OVER THE NORTHERN SIERRA AND WESTERN NEVADA ON
CHRISTMAS EVE. CONFIDENCE REMAINS AT MEDIUM FOR A WHITE CHRISTMAS AS
THE COLD FRONT MAY BRING A PERIOD OF SNOW TO AREAS NORTH OF CARSON
PASS TO FALLON. THOSE TRAVELING CHRISTMAS EVE AND CHRISTMAS MORNING
SHOULD KEEP AN EYE ON THE FORECAST FOR POTENTIAL IMPACTS TO TRAVEL
DUE TO WINDS AND/OR SNOW.

WINDS WILL KICK UP AHEAD OF THE SYSTEM WEDNESDAY AFTERNOON WITH
POTENTIAL FOR GUSTS OF 35-50 MPH ON CHRISTMAS EVE. WIND PRONE
LOCATIONS COULD GUST UP NEAR 60 MPH. WITH THE IMPROVED MIXING, HIGHS
IN THE NEVADA VALLEYS MAY RISE INTO THE LOW 60S AND ANY HAZE AND
POLLUTANTS TRAPPED IN THE VALLEYS WILL CLEAR OUT.

A FEW SHOWERS MAY LINGER FOR CHRISTMAS MORNING WITH A COLD  NORTH TO
NORTHWEST WIND. HIGHS CHRISTMAS DAY MAY STRUGGLE TO REACH 40 ACROSS
THE NEVADA VALLEYS WITH 30S IN THE SIERRA.

AFTER CHRISTMAS, LARGE MODEL DIFFERENCES ARISE AS A BLOCKING PATTERN
MAY DEVELOP OVER THE EASTERN PACIFIC. MODELS ARE SPLIT ON EITHER A
COLD LOW DROPPING INTO THE GREAT BASIN FROM WESTERN CANADA, OR A LOW
CUTTING INTO THE CALIFORNIA COAST AS THE RIDGE IS PINCHED NORTHWARD.
EITHER SYSTEM COULD BRING RAIN AND/OR SNOW TO THE REGION ON SUNDAY,
BUT NOTHING THAT LOOKS IMPRESSIVE AT THIS TIME. BRONG

&&

.AVIATION...

MOIST ONSHORE FLOW CONTINUES WITH GUSTY WINDS NORTH OF PORTOLA TO
LOVELOCK. A FEW LIGHT SHOWERS ARE POSSIBLE NORTH OF KTRK-KLOL WITH
FREEZING LEVELS ABOVE 7000-8000 FEET.

HIGH PRESSURE WILL BUILD INTO THE NORTHERN SIERRA BY MONDAY MORNING
WITH DECREASING WINDS. NEXT SYSTEM OF NOTE WILL ARRIVE ON WEDNESDAY
WITH INCREASING WINDS, MOUNTAIN WAVES AND SNOW POSSIBLE FOR
CHRISTMAS EVE AND CHRISTMAS MORNING NORTH OF KTVL-KNFL. BRONG

&&


.REV WATCHES/WARNINGS/ADVISORIES...
NV...WIND ADVISORY UNTIL 3 PM PST THIS AFTERNOON NVZ005.

CA...WIND ADVISORY UNTIL 3 PM PST THIS AFTERNOON CAZ070.

&&

$$

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







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