Area Forecast Discussion
Issued by NWS Reno, NV

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000
FXUS65 KREV 231000
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
300 AM PDT THU OCT 23 2014

.SYNOPSIS...
AFTERNOON TEMPERATURES WILL WARM THROUGH FRIDAY. MOISTURE AHEAD
OF A LOW PRESSURE SYSTEM IN THE PACIFIC WILL PRODUCE RAIN OVER
NORTHEAST CALIFORNIA AND FAR NORTHWEST NEVADA TODAY. THE LOW WILL
MOVE INLAND ON SATURDAY BRINGING A PERIOD OF STRONG GUSTY WINDS
AND THE POTENTIAL FOR RAIN AND MOUNTAIN SNOW.

&&

.SHORT TERM...

MAIN UPDATES IN THE SHORT TERM WERE TO INCREASE WINDS SATURDAY
AFTERNOON AND EVENING, AND INCREASE PRECIPITATION CHANCES SATURDAY
NIGHT, ESPECIALLY FROM THE TAHOE BASIN NORTH TO LASSEN COUNTY.

FOR TODAY AND TONIGHT, A PACIFIC TROUGH WILL CONTINUE TO
TRANSPORT MOISTURE ACROSS NORTHERN CALIFORNIA AND NORTHWEST NV.
HRRR MODEL SHOWS PRECIPITATION SPREADING AS FAR SOUTH AS PLUMAS
COUNTY TODAY. THIS SEEMS REASONABLE BASED ON CURRENT
RADAR/SATELLITE TRENDS. AMOUNTS IN THE SURPRISE VALLEY HAVE BEEN
CLOSE TO 0.10 INCHES ALREADY THIS MORNING. THIS MOISTURE PLUME
WILL SHIFT NORTHWARD INTO OREGON BY FRIDAY MORNING. WEAK
ISENTROPIC LIFT SHOULD PROVIDE TOTAL PRECIPITATION AMOUNTS
GENERALLY IN THE 0.10 TO 0.30 INCHES RANGE BY FRIDAY MORNING,
WITH HIGHER AMOUNTS POSSIBLE NEAR THE OREGON BORDER.

A STRONGER PACIFIC TROUGH WILL REACH THE WEST COAST FRIDAY AND
WILL BRING INCREASING SOUTH-SOUTHWEST WINDS TO THE SIERRA AND
WESTERN NV. SIERRA RIDGE GUSTS SHOULD INCREASE TO 30-50 MPH FRIDAY
AND INTO THE 20-30 MPH RANGE IN WESTERN NV VALLEYS. RIDGE GUSTS
SHOULD BECOME EVEN STRONGER FRIDAY NIGHT, AROUND 50-60 MPH BY
FRIDAY EVENING, AND 60-80 MPH FRIDAY AFTER MIDNIGHT.

MODEL AND MODEL ENSEMBLES ARE COMING INTO FAIRLY GOOD AGREEMENT
THAT A COLD FRONT AND WINTER-LIKE SYSTEM WILL CROSS THE SIERRA
AND SIERRA FRONT RANGE SATURDAY AFTERNOON AND EVENING. WINDS ARE
EXPECTED TO INCREASE TO ADVISORY LEVEL SATURDAY, WITH GUSTS IN
VALLEYS TO 40-50 MPH AND RIDGE TOP GUSTS 80-100 MPH OR HIGHER.

THIS COLD FRONT IS ALSO LIKELY TO BRING RAIN AND SNOW SATURDAY
FROM THE TAHOE BASIN NORTH. SNOW LEVELS SATURDAY EVENING COULD
LOWER TO AROUND 7000 FEET NORTH OF I-80, AND TO 7000-8000 FEET
SOUTH OF I-80. PRECIPITATION AMOUNTS ARE UNCERTAIN AT THIS TIME,
BUT THERE IS POTENTIAL FOR AT LEAST A FEW INCHES OF SNOW TO IMPACT
MOUNTAIN PASSES ABOVE 7000 FEET STARTING SATURDAY EVENING. JCM

.LONG TERM...SUNDAY THROUGH WEDNESDAY...
TROUGH WILL BE EXITING SUNDAY WITH A MUCH COOLER NORTHERLY FLOW.
TEMPERATURES WILL BE MOSTLY IN THE 50S AREA WIDE. WE DID BUMP POPS UP
SLIGHTLY FOR SUNDAY MORNING AS PRECIPITATION WILL BE ONGOING BUT
WINDING DOWN. QPF WILL BE LIGHT AND GENERALLY UNDER 1/10 INCH.
SHOWERS WILL DECREASE DURING THE AFTERNOON AND BE CONFINED MAINLY TO
FAR NORTHERN AREAS, CLOSE TO THE OREGON BORDER.

A PROGRESSIVE FLOW WILL PREVAIL MONDAY-WEDNESDAY WHICH WILL BRING
PERIODS OF CLOUDS AND A SLOW WARMUP. WE DID KEEP A SLIGHT CHANCE OF
SHOWERS GOING NORTHERN AREAS AS MODELS ARE INDICATING A WEAK
SHORTWAVE MOVING THROUGH THE FLOW TUE-WED. THIS IS A RATHER WEAK
FEATURE AND WILL RESULT IN LIGHT QPF. OTHERWISE ATTENTION WILL
EVENTUALLY TURN TO THE END OF NEXT WEEK WHEN A MORE SIGNIFICANT
TROUGH IS POSSIBLE. THE GFS HAS BEEN CHANGING ERRATICALLY THE PAST
FEW NIGHTS AND WE HAVE DISREGARDED THE UPPER RIDGE DEPICTED IN ITS
DETERMINISTIC RUN. ITS PREVIOUS 18Z RUN AND SEVERAL OF ITS CURRENT
ENSEMBLE MEMBERS ARE MORE ALIGNED WITH THE EC/GEM, THE ECMWF BEING
PERSISTENT NOW FOR SEVERAL RUNS. IN ADDITION THE ECMWF HAS BETTER
SUPPORT FROM ITS ENSEMBLE MEAN. NONETHELESS, CONFIDENCE IS STILL
LOW. IT WILL BE WORTH WATCHING. HOHMANN

&&

.AVIATION...
A BAND OF RAIN WILL CONTINUE ACROSS NORTHEAST CA AND FAR NORTHWEST
NV THROUGH TONIGHT BEFORE LIFTING NORTHWARD ON FRIDAY. CONDITIONS
WILL GENERALLY BE VFR WITH LIGHT RAIN ALTHOUGH CLOUD DECKS COULD
LOWER TO BKN-OVC030 AT TIMES IN MODERATE RAIN, MAINLY NORTH OF A
SUSANVILLE TO GERLACH LINE.

ELSEWHERE, VFR CONDITIONS WITH GUSTY RIDGE LEVEL WINDS. SOME LEE
SIDE TURBULENCE IS POSSIBLE AS SIERRA RIDGES GUST TO 50KT THROUGH
FRIDAY.

A LOW PRESSURE TROUGH AND COLD FRONT WILL BRING A SUBSTANTIAL
INCREASE IN WINDS SATURDAY WHEN WIDESPREAD WIND GUSTS TO 40KT OR
MORE ARE POSSIBLE. HOHMANN

&&

.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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