Area Forecast Discussion
Issued by NWS Reno, NV

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000
FXUS65 KREV 212223
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
223 PM PST SUN DEC 21 2014

.SYNOPSIS...
WINDS WILL DIMINISH THIS EVENING AS HIGH PRESSURE SLOWLY BUILDS
IN. DRY CONDITIONS AND MILD TEMPERATURES ARE ANTICIPATED TODAY
THROUGH WEDNESDAY AS HIGH PRESSURE REMAINS. A STRONG COLD FRONT IS
POSSIBLE LATE WEDNESDAY INTO CHRISTMAS DAY WITH GUSTY WINDS, RAIN,
AND SNOW.

&&

.SHORT TERM...
WINDS HAVE CONTINUED TO BLOW ACROSS THE SURPRISE VALLEY EARLY THIS
AFTERNOON WITH PEAK GUSTS STILL AROUND 50 MPH. WITH THE SURFACE
GRADIENT STILL STRONG AND SUPPORTIVE WINDS ALOFT WILL EXTEND THE
WIND ADVISORY THROUGH 10 PM THIS EVENING. ELSEWHERE, WINDS
CONTINUE TO BE LOCALLY GUSTY WITH SOME GUSTS 40-45 MPH ACROSS
PARTS OF WEST RENO AND THE RED ROCK AREA. THESE WINDS SHOULD ALSO
DIMINISH THIS EVENING.

THE RIDGE FOR EARLY THIS WEEK ADVERTISED BY THE MODELS CAN NOW BE
SEEN SLOWLY BUILDING IN THE EAST PACIFIC. THE RIDGE WILL NOSE EAST
AND PUSH MOST OF THE PRECIP/WINDS NORTH AND EAST MONDAY AND
TUESDAY. THERE WILL BE A WEAK BACKDOOR FRONT MONDAY MORNING, WITH
SOME LOCALLY GUSTY WINDS. THIS WILL ALSO ALLOW TEMPS TO COOL A FEW
DEGREES TOMORROW AT LEAST IN THE LOWER VALLEYS FROM TODAY`S NEAR
RECORD TEMPS. TEMPS MAY COOL FURTHER IN THE VALLEYS TUESDAY AS A
MODERATE INVERSION FORMS AFTER RADIATIONAL COOLING TOMORROW NIGHT.
HOWEVER, MTN TEMPS SHOULD REMAIN MILD AS TEMPS ALOFT HOLD STEADY.

MAIN CONCERN THEN TURNS TO WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT
AS THE NEXT SYSTEM APPROACHES. ALL THE MODELS SHOW IT TO BE A
QUICK MOVER, BUT DIFFER ON THE EXACT TRACK. THE GFS CONTINUES TO
BE THE FASTEST AND FURTHEST NORTH/EAST WHILE THE EC IS DEEPER AND
WETTER. WE ARE CURRENTLY LEANING TOWARD THE EC FOR TWO REASONS. 1)
IT HAS BEEN MORE CONSISTENT THE PAST FEW DAYS. 2) IT HAS GOOD
SUPPORT FROM ITS ENSEMBLE WHICH SHOWS THE GFS TO BE A FAST
OUTLIER. IF ANYTHING, THE EC ENSEMBLE MEAN IS EVEN DEEPER/STRONGER
THAN ITS OPERATIONAL RUN.

GIVEN THIS IDEA, HAVE INCREASED THE WINDS AND TEMPS FOR WEDNESDAY
AFTERNOON AND EVENING. THE EC IS SHOWING A STRONG SURFACE PRESSURE
AND ISALLOBARIC GRADIENT SUPPORTIVE OF STRONG WINDS ALONG WITH 50
KTS AT 700 MB. IF THIS IS TRUE, GUSTS OF 50+ MPH ARE POSSIBLE
AHEAD OF THE FRONT. AS FOR PRECIP, HAVE INCREASED THE CHANCES
SLIGHTLY AND LOWERED SNOW LEVELS A LITTLE WITH THE COLDER IDEA.
MOST PRECIP WILL BE BEHIND THE FRONT WHICH WILL MAKE IT MOSTLY
SNOW EVEN TO THE VALLEY FLOORS. STILL ONLY LOW TO MODERATE
CONFIDENCE BUT THE POSSIBILITY REMAINS FOR A WHITE CHRISTMAS IN
MANY VALLEYS NORTH OF HIGHWAY 50. WALLMANN

.LONG TERM...THURSDAY THROUGH SUNDAY...
WITH THE 12Z ECMWF GAINING MORE SUPPORT FROM THE 18Z NAM AND GFS
FOR A MORE AGGRESSIVE COLD FRONT PASSAGE AND SNOW POTENTIAL ON
CHRISTMAS EVE, WE WILL KEEP CHRISTMAS DAY ON THE COOL SIDE WITH
LINGERING SNOW SHOWERS ENDING DURING THE MORNING. IF SNOW
ACCUMULATES OVERNIGHT, HIGHS MAY STRUGGLE TO REACH 40 ACROSS SOME
NEVADA VALLEYS WITH 30S IN THE SIERRA.

THURSDAY NIGHT LOOKS QUITE CHILLY WITH CLEARING SKIES AND LIGHT
WINDS ALLOWING TEMPS TO DROP INTO THE TEENS FOR MOST LOWER
ELEVATIONS, WITH SINGLE DIGITS IN TYPICALLY COOLER VALLEYS NEAR THE
SIERRA AND AWAY FROM URBAN AREAS.

AFTER CHRISTMAS DAY, DRY CONDITIONS WITH DAYTIME TEMPS NEAR NORMAL
ARE LIKELY TO PREVAIL INTO MUCH OF NEXT WEEKEND AS RIDGE REBUILDS
NEAR THE WEST COAST. THE RIDGE COULD BRIEFLY BUILD INLAND BY EARLY
NEXT WEEKEND, BUT OVERALL IT APPEARS THAT ANOTHER SHORTWAVE PASSAGE
FROM THE NORTH WILL PUSH THE RIDGE AXIS OFF THE WEST COAST NEXT
SUNDAY OR SUNDAY NIGHT. ANOTHER ROUND OF LIGHT SNOW OR RAIN COULD
ARRIVE NORTH OF SUSANVILLE BY SUNDAY AFTERNOON, BUT BETTER POTENTIAL
FOR PRECIP APPEARS TO HOLD OFF UNTIL SUNDAY NIGHT. MJD

&&

.AVIATION...
GUSTY W-NW WINDS UP TO 25 KT AROUND KRNO-KCXP-KMMH WILL DIMINISH
BEFORE 03Z THIS EVENING, WITH LIGHTER WINDS EXPECTED FOR KTVL-
KTRK. WINDS WILL BE STRONGER THRU 06Z THIS EVENING FOR EXTREME
NERN CA-NWRN NV. VFR CONDS WILL PREVAIL THRU TONIGHT EXCEPT FOR
AREAS OF FZFG DEVELOPING AROUND KTRK MAINLY BTWN 08-16Z.

HIGH PRESSURE WILL BUILD INTO THE NORTHERN SIERRA BY MONDAY MORNING
WITH LIGHTER WINDS EXPECTED MONDAY AND TUESDAY. NEXT NOTABLE WEATHER
SYSTEM WILL ARRIVE ON WEDNESDAY WITH INCREASING WINDS, MOUNTAIN
WAVES AND SNOW POSSIBLE FOR CHRISTMAS EVE AND CHRISTMAS MORNING
NORTH OF KTVL-KNFL. MJD

&&


.REV WATCHES/WARNINGS/ADVISORIES...
NV...WIND ADVISORY UNTIL 10 PM PST THIS EVENING NVZ005.

CA...WIND ADVISORY UNTIL 10 PM PST THIS EVENING CAZ070.

&&

$$

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








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