Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 230319
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
819 PM PDT WED OCT 22 2014

.UPDATE...
WILL DO A MINOR UPDATE TO INCREASE POPS SLIGHTLY OVER THE FAR
NORTH AND NORTHWEST CWA TONIGHT. SATELLITE IMAGERY SHOWS
THICKENING CLOUDS WITH SOME COOLING TOPS WHILE RADAR IMAGERY
SHOWS LIGHT RETURNS OVER LASSEN COUNTY ALREADY. THESE MAY NOT BE
REACHING THE GROUND...BUT WILL HELP TO MOISTEN THE LOWER PORTIONS
OF THE ATMOSPHERE THROUGH THE EVENING. A FEW SPRINKLES ARE NOT OUT
OF THE QUESTION BEFORE MIDNIGHT. MODELS STILL DO NOT SHOW MUCH
WIDESPREAD LIFT...OTHER THAN SOME ISENTROPIC LIFT...SO ANY PCPN
SHOULD BE FAIRLY LIGHT. 20

&&

.PREVIOUS DISCUSSION... /ISSUED 300 PM PDT WED OCT 22 2014/

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

SHORT TERM...

RIDGE OF HIGH PRESSURE CONTINUES TO BREAK DOWN TONIGHT AS LOW
PRESSURE MOVES INTO THE PACIFIC NORTHWEST COAST. AHEAD OF THE TROUGH
IN NORTHERN CA, WE`LL SEE WEAK ISENTROPIC LIFT IN THE WARM CONVEYOR
BELT. MOST OF THE DYNAMICS WITH THIS SYSTEM WILL MISS OUR AREA TO
THE NORTH, BUT IT WILL BRING SOME LIGHT TO MODERATE RAIN INTO THE
NORTHERN SIERRA THURSDAY AND THURSDAY NIGHT, MAINLY NORTH OF LAKE
TAHOE IN LASSEN, PLUMAS AND MODOC COUNTIES. TOTAL AMOUNT OF RAINFALL
WEST OF HIGHWAY 395 IN NORTHEASTERN CALIFORNIA WILL GET UP TO 0.25"
OF RAINFALL, WHILE AREAS ALONG AND EAST OF HWY 395 WILL GET 0.10" OR
LESS. SINCE MOST OF THIS PRECIP IS ASSOCIATED WITH THE WARM CONVEYOR
BELT, SNOW LEVELS WILL REMAIN FAIRLY HIGH AROUND 9000-10000FT OR MORE.

INCREASED CLOUDS ON THURSDAY MAY PUT A DAMPER ON VIEWING
OPPORTUNITIES IN THE AREA FOR THE PARTIAL SOLAR ECLIPSE LATE IN THE
DAY. AREAS SOUTH OF HIGHWAY 50 WILL HAVE THE LEAST CLOUDS THURSDAY
AND THUS THE BEST CHANCES FOR VIEWING THE ECLIPSE.

BY FRIDAY, A STRONG JET MAX MOVING INTO THE PAC NW WILL LIFT THE
RIDGE OVER NEVADA, PULLING CHANCES FOR PRECIP OUT OF OUR AREA. WE`VE
REMOVED MENTION OF PRECIP FRIDAY AND FRIDAY NIGHT. THE MODELS ARE
ALSO TRENDING SLOWER WITH THE STRONGER WINDS, SO WE`VE ALSO LOWERED
THE WIND SPEEDS ON FRIDAY AS WELL. THE ADVANCING TROUGH OFF THE
NORCAL COAST WILL SHIFT THE UPPER LEVEL FLOW TO MORE OF A SOUTHERLY
DIRECTION WITH RIDGE LEVEL WINDS INCREASING TO OVER 50 MPH LATE
FRIDAY NIGHT. HOON

LONG TERM...SATURDAY THROUGH WEDNESDAY...

ONLY A FEW ADJUSTMENTS WERE NECESSARY TO THE EXISTING FORECAST AS WE
CONTINUE THROUGH A FAIRLY UNSETTLED PERIOD OF WEATHER. THE MAIN
CHANGES CONCERN TIMING VARIANCES AS MODELS RESOLVE MAJOR FEATURES.
THE SYSTEM APPROACHING THIS WEEKEND, FOR INSTANCE, HAS SLOWED A
LITTLE. THEREFORE, IT WAS NECESSARY TO TRIM PRECIPITATION CHANCES
MOSTLY OUT OF CHURCHILL AND PERSHING COUNTIES. AS THE WAVE SPLITS,
ANOTHER JET IMPULSE ENTERS THE BASE OF THE TROUGH OFF THE CALIFORNIA
COAST. THIS WILL AMPLIFY THE LONGWAVE PATTERN WHILE SLOWING THE
EASTWARD PROGRESSION OF THE APPROACHING SYSTEM. ADDITIONALLY, WITH
THE INCREASINGLY AMPLIFIED PATTERN, THE TRACK OF THE SURFACE LOW
WILL BE MORE LATITUDINAL RATHER THAN THE EASTWARD PUSH WE WERE
EXPECTING BEFORE. THE PATTERN`S SHIFT WILL FAVOR PRECIPITATION FROM
THE TAHOE BASIN NORTHWARD WITH LESS SPILLING OVER INTO WESTERN
NEVADA. THIS RESULTED IN LOWERING CHANCES ALONG THE SIERRA FRONT
DURING THE DAY ON SATURDAY.

WINDS WILL BE THE PRIMARY THREAT EARLY IN THE WEEKEND AS THE
PRESSURE GRADIENT TIGHTENS FROM NORTH TO SOUTH ALONG THE SIERRA
INTO WESTERN NEVADA. SPECIFICALLY, EARLY SATURDAY AFTERNOON, WINDS
WILL INCREASE ALONG THE SIERRA FRONT AND IN THE EASTERN SIERRA
PRODUCING GUSTS IN THE 35-45 MPH RANGE. WHILE WINDS DECREASE LATE
SATURDAY AFTERNOON ALONG THE SIERRA FRONT, CONDITIONS WILL REMAIN
BREEZY INTO THE EVENING AND OVERNIGHT HOURS ESPECIALLY FOR LOCATIONS
NORTH OF INTERSTATE 80.

LOW CHANCES OF PRECIPITATION WILL CONTINUE THROUGH SUNDAY AS YET
ANOTHER IMPULSE MOVES THROUGH NORTHEAST CALIFORNIA AND WESTERN
NEVADA. THESE CHANCES OF MOSTLY RAIN AND HIGH ELEVATION SNOW WILL
EXIT BY EARLY MONDAY MORNING WITH LOW AMPLITUDE RIDGING TRANSITING
THE WESTERN UNITED STATES. THE NEXT WAVE WILL APPROACH MID TO LATE
WEEK WITH ANOTHER ROUND OF GENERALLY LIGHT PRECIPITATION. BOYD

AVIATION...

VFR CONDITIONS AND LIGHT WINDS CONTINUE THIS AFTERNOON INTO THURSDAY
WITH AREAS OF HIGH CLOUDS OVERHEAD. INCREASING PACIFIC MOISTURE WILL
BRING A BAND OF RAIN MAINLY NORTH OF SUSANVILLE-GERLACH LINE BY
THURSDAY MORNING, WITH LIGHTER RAIN SHOWERS POSSIBLY SPREADING
SOUTHWARD TO NEAR INTERSTATE 80. WINDS WILL ALSO INCREASE TONIGHT
INTO THURSDAY OVER RIDGES WITH GUSTS AROUND 40KT.

MORE INCLEMENT WEATHER IN THE FORM OF STRONG SURFACE WINDS WILL
ARRIVE OVER THIS WEEKEND. GUSTS UP TO 40KTS ARE EXPECTED EARLY
SATURDAY INTO SATURDAY EVENING AS A STRONGER SYSTEM APPROACHES THE
SIERRA. ADDITIONALLY, HIGH ELEVATION SNOWS WILL BE POSSIBLE IN THE
SIERRA WITH THE STRONG LIKELIHOOD OF DEGRADED CEILINGS TO AT LEAST
MVFR AND POSSIBLY IFR ON SATURDAY AT SIERRA TERMINALS. WH/BOYD

&&

.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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