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000
FXUS65 KREV 190221 CCA
AFDREV

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE RENO NV
328 PM PST THU DEC 18 2014

CORRECTED TO ADD AVIATION DISCUSSION

.SYNOPSIS...
A COUPLE WEAK STORMS WILL BRING CHANCES FOR RAIN AND SNOW FRIDAY
THROUGH SATURDAY MAINLY NORTH OF HIGHWAY 50. HIGH PRESSURE WILL
THEN BUILD SUNDAY THROUGH THE FIRST PART OF NEXT WEEK. A COOLING
TREND IS POSSIBLE LATE NEXT WEEK.

&&

.SHORT TERM...
FEW CHANGES MADE OVERALL WITH THE MODELS IN REASONABLY GOOD
AGREEMENT WITH THE WEAKENING SYSTEM ARRIVING FRIDAY MORNING.
EXPECT ANOTHER MILD NIGHT TONIGHT WITH SOME ABUNDANT MID AND HIGH
CLOUD COVER AHEAD OF THE SYSTEM.

THE BULK OF THE SYSTEM ARRIVES FRIDAY MORNING AND ALL THE MODELS
SHOWING IT SPLITTING AND WEAKENING AS IT ARRIVES. WHAT LITTLE JET
ENERGY IS LEFT IS FORECAST TO REMAIN IN OREGON WITH ONLY THE WEAK
LEFT OVER LOW-LEVEL FRONT MAKING IT AS FAR SOUTH AS I-80. THERE IS
ENOUGH MOISTURE TO SQUEEZE OUT SOME RAIN AND SNOW OVER THE SIERRA
FROM TAHOE NORTH. EXPECT LITTLE SPILLING OVER INTO WESTERN NEVADA
EXCEPT NEAR THE OREGON BORDER CLOSER TO THE FORCING WITH THE WEAK
UPPER JET. SNOW LEVELS WILL REMAIN NEAR 6000-6500 FEET AROUND I-80
AND 4500-5000 FEET NEAR THE OREGON BORDER. LIGHT SNOW AMOUNTS OF
UP TO A COUPLE INCHES ARE POSSIBLE ABOVE THIS LEVEL WITH HIGHER
AMOUNTS TO 6 INCHES NEAR THE SIERRA CREST.

AS THIS SYSTEM PULLS AWAY FRIDAY NIGHT, EXPECT A DECREASING CHANCE
OF SHOWERS BUT CLOUD COVER WILL CONTINUE TO KEEP OVERNIGHT TEMPS
MILD. ON SATURDAY, THE PACIFIC JET REORGANIZES AND IS DIRECTED
INTO WASHINGTON. HOWEVER, A MOIST PACIFIC PLUME WILL EXTEND SOUTH
INTO NORTHERN CALIFORNIA AND NEVADA. SOME DECENT ISENTROPIC LIFT
IS SHOWN WITH WARM AIR ADVECTION SATURDAY. THE BEST CHANCE WILL
OCCUR NEAR THE OREGON BORDER WITH CHANCES TAPERING TO NOTHING
SOUTH OF HIGHWAY 50. SNOW LEVELS WITH THIS ONE WILL BE MORE
PROBLEMATIC AS MODEL SOUNDING SHOW ISOTHERMAL PROFILES HOVERING
NEAR FREEZING. THIS COULD KEEP SNOW LEVELS NEAR THE VALLEY FLOORS
IN THE SURPRISE VALLEY BEFORE RAPIDLY RISING TO ABOVE 8000 FEET
WITH THE PASSAGE OF THE WARM FRONT.

AFTER THIS WAVE PASSES SATURDAY NIGHT, THE RIDGE WILL AMPLIFY JUST
OFF THE COAST BRINGING A WARMING AND DRYING TREND. WITH ABUNDANT
CLOUD COVER AGAIN SATURDAY NIGHT BEFORE THE SYSTEM EXITS, TEMPS
COULD AGAIN BE MILD. WARM TEMPS COULD FOLLOW SUNDAY THAT MAY BE
10-15 DEGREES ABOVE NORMAL AS RIDGE TOP (10,000 FOOT) TEMPS RISE
ABOVE FREEZING. WALLMANN

.LONG TERM...MONDAY THROUGH THURSDAY/CHRISTMAS DAY...
AN UPPER RIDGE WILL RULE THE EASTERN SIERRA AND WESTERN NEVADA
MONDAY AND TUESDAY. THIS WILL BRING LIGHT VALLEY WINDS AND HIGH
TEMPERATURES NEAR TO SLIGHTLY ABOVE (4-7 DEGREES) AVERAGE. THE LIGHT
WINDS AND STABLE CONDITIONS WILL ALLOW POLLUTANT BUILDUP FOR THE
VALLEYS, ESPECIALLY FOR THE RENO-SPARKS AREA. HOWEVER, THE LACK OF
SNOW COVER AND A RELATIVELY MILD AIRMASS SHOULD ALLOW FOR A SOMEWHAT
DEEPER MIXED LAYER IN THE AFTERNOONS (MORE ROOM FOR THE POLLUTANTS
TO RISE UP AWAY FROM THE SURFACE).

ON WEDNESDAY AND WEDNESDAY NIGHT (CHRISTMAS EVE), ATTENTION TURNS TO
THE POTENTIAL FOR AN INSIDE SLIDER-TYPE SYSTEM. THESE TYPES OF
SYSTEMS ARE OF SPECIAL INTEREST TO LOCATIONS EAST OF THE SIERRA IN
WESTERN NEVADA AS THEY CAN BRING SOME OF THE HEAVIEST SNOWFALL
RATES/AMOUNTS SEEN IN THE WESTERN GREAT BASIN (DESPITE THEIR
TYPICALLY LIMITED MOISTURE).

TO TALK FIRST ABOUT WHAT WE FEEL CONFIDENT IN, THERE WILL BE A
STRONG COLD FRONT THAT MOVES THROUGH CHRISTMAS EVE INTO VERY EARLY
CHRISTMAS MORNING. CHRISTMAS DAY LOOKS CHILLY WITH HIGH TEMPERATURES
FALLING TO AT LEAST 5-10 DEGREES BELOW AVERAGE (A 15-25 DEGREE DROP
FROM WEDNESDAY`S HIGH). ALSO, GIVEN SUCH A STRONG FROPA AND GOOD
MIXING PRIOR TO THE FRONTAL PASSAGE, IT IS LIKELY TO BE QUITE BREEZY
CHRISTMAS EVE, ESPECIALLY BY AFTERNOON AND EVENING.

THE REAL UNCERTAINTIES WILL BE IN WHETHER WE GET A BAND OF MODERATE
TO HEAVY SNOW ALONG THE FRONT OR NOTHING MORE THAN ISOLATED TO
SCATTERED LIGHT SNOW (OR RAIN CHANGING QUICKLY TO SNOW) SHOWERS. A
SECOND UNCERTAINTY IS JUST HOW COLD IT WILL GET BEHIND THE FRONT ON
THURSDAY. A LOT OF THAT DEPENDS ON SNOWFALL, AS A COUPLE INCHES OF
SNOW ON CHRISTMAS EVE WOULD KNOCK HIGHS ON CHRISTMAS DOWN FROM THE
30S TO THE 20S FOR MOST AREAS.

RIGHT NOW, MODELS ARE FIGHTING BETWEEN AN UPPER LOW OVER FAR WESTERN
NEVADA (BULLSEYE FOR HEAVY SNOW) OR A GLANCING BLOW WITH AN UPPER
LOW OVER IDAHO (MAYBE A FEW LIGHT SHOWERS). THERE ARE SIGNIFICANT
IMPACTS IF THE WESTERN SOLUTION VERIFIES AND IT WILL PROBABLY TAKE
UNTIL EARLY NEXT WEEK FOR MODELS TO ZERO IN ON A SOLUTION SO STAY
TUNED. SNYDER

&&

.AVIATION...
RIDGE OF HIGH PRESSURE BUILDS OVER THE REGION WITH DRY CONDITIONS
THROUGH LATE TONIGHT. FOG IS NOT OUT OF THE QUESTION FOR THE MARTIS
VALLEY/KTRK TONIGHT, ALTHOUGH IT WILL LIKELY REMAIN PATCHY WITH
INCREASING CLOUDS AND FLOW ALOFT TO DISRUPT ITS FORMATION. FARTHER
SOUTH NEAR CROWLEY AND MONO LAKES (HWY 395) LOW CLOUDS AND FREEZING
FOG ARE LIKELY AGAIN TONIGHT AS CLOUDS TAKE LONGER TO INCREASE IN
THAT AREA.

A COLD FRONT MOVES INTO THE REGION ON FRIDAY. SOUTHWEST-WEST WINDS
WILL INCREASE WITH SOME TURBULENCE DOWNWIND OF THE SIERRA,
ESPECIALLY THROUGH AROUND MIDDAY AHEAD OF THE FRONT. AS FAR AS
PRECIPITATION, IT LOOKS MAINLY CONFINED TO THE SIERRA AND NEVADA
NORTH OF A PYRAMID LAKE-KWMC LINE. WITH FAIRLY LOW SNOW LEVELS, IFR
CONDITIONS WITH WIDESPREAD TERRAIN OBSCURATION LIKELY IN THE SIERRA
ALTHOUGH SNOWFALL LOOKS TO REMAIN LIGHT (A FEW INCHES). FOR WESTERN
NEVADA, HIGHER TERRAIN OBSCURATION IN RAIN/SNOW SHOWERS WILL BE THE
MAIN IMPACT. SNYDER

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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










000
FXUS65 KREV 190221 CCA
AFDREV

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE RENO NV
328 PM PST THU DEC 18 2014

CORRECTED TO ADD AVIATION DISCUSSION

.SYNOPSIS...
A COUPLE WEAK STORMS WILL BRING CHANCES FOR RAIN AND SNOW FRIDAY
THROUGH SATURDAY MAINLY NORTH OF HIGHWAY 50. HIGH PRESSURE WILL
THEN BUILD SUNDAY THROUGH THE FIRST PART OF NEXT WEEK. A COOLING
TREND IS POSSIBLE LATE NEXT WEEK.

&&

.SHORT TERM...
FEW CHANGES MADE OVERALL WITH THE MODELS IN REASONABLY GOOD
AGREEMENT WITH THE WEAKENING SYSTEM ARRIVING FRIDAY MORNING.
EXPECT ANOTHER MILD NIGHT TONIGHT WITH SOME ABUNDANT MID AND HIGH
CLOUD COVER AHEAD OF THE SYSTEM.

THE BULK OF THE SYSTEM ARRIVES FRIDAY MORNING AND ALL THE MODELS
SHOWING IT SPLITTING AND WEAKENING AS IT ARRIVES. WHAT LITTLE JET
ENERGY IS LEFT IS FORECAST TO REMAIN IN OREGON WITH ONLY THE WEAK
LEFT OVER LOW-LEVEL FRONT MAKING IT AS FAR SOUTH AS I-80. THERE IS
ENOUGH MOISTURE TO SQUEEZE OUT SOME RAIN AND SNOW OVER THE SIERRA
FROM TAHOE NORTH. EXPECT LITTLE SPILLING OVER INTO WESTERN NEVADA
EXCEPT NEAR THE OREGON BORDER CLOSER TO THE FORCING WITH THE WEAK
UPPER JET. SNOW LEVELS WILL REMAIN NEAR 6000-6500 FEET AROUND I-80
AND 4500-5000 FEET NEAR THE OREGON BORDER. LIGHT SNOW AMOUNTS OF
UP TO A COUPLE INCHES ARE POSSIBLE ABOVE THIS LEVEL WITH HIGHER
AMOUNTS TO 6 INCHES NEAR THE SIERRA CREST.

AS THIS SYSTEM PULLS AWAY FRIDAY NIGHT, EXPECT A DECREASING CHANCE
OF SHOWERS BUT CLOUD COVER WILL CONTINUE TO KEEP OVERNIGHT TEMPS
MILD. ON SATURDAY, THE PACIFIC JET REORGANIZES AND IS DIRECTED
INTO WASHINGTON. HOWEVER, A MOIST PACIFIC PLUME WILL EXTEND SOUTH
INTO NORTHERN CALIFORNIA AND NEVADA. SOME DECENT ISENTROPIC LIFT
IS SHOWN WITH WARM AIR ADVECTION SATURDAY. THE BEST CHANCE WILL
OCCUR NEAR THE OREGON BORDER WITH CHANCES TAPERING TO NOTHING
SOUTH OF HIGHWAY 50. SNOW LEVELS WITH THIS ONE WILL BE MORE
PROBLEMATIC AS MODEL SOUNDING SHOW ISOTHERMAL PROFILES HOVERING
NEAR FREEZING. THIS COULD KEEP SNOW LEVELS NEAR THE VALLEY FLOORS
IN THE SURPRISE VALLEY BEFORE RAPIDLY RISING TO ABOVE 8000 FEET
WITH THE PASSAGE OF THE WARM FRONT.

AFTER THIS WAVE PASSES SATURDAY NIGHT, THE RIDGE WILL AMPLIFY JUST
OFF THE COAST BRINGING A WARMING AND DRYING TREND. WITH ABUNDANT
CLOUD COVER AGAIN SATURDAY NIGHT BEFORE THE SYSTEM EXITS, TEMPS
COULD AGAIN BE MILD. WARM TEMPS COULD FOLLOW SUNDAY THAT MAY BE
10-15 DEGREES ABOVE NORMAL AS RIDGE TOP (10,000 FOOT) TEMPS RISE
ABOVE FREEZING. WALLMANN

.LONG TERM...MONDAY THROUGH THURSDAY/CHRISTMAS DAY...
AN UPPER RIDGE WILL RULE THE EASTERN SIERRA AND WESTERN NEVADA
MONDAY AND TUESDAY. THIS WILL BRING LIGHT VALLEY WINDS AND HIGH
TEMPERATURES NEAR TO SLIGHTLY ABOVE (4-7 DEGREES) AVERAGE. THE LIGHT
WINDS AND STABLE CONDITIONS WILL ALLOW POLLUTANT BUILDUP FOR THE
VALLEYS, ESPECIALLY FOR THE RENO-SPARKS AREA. HOWEVER, THE LACK OF
SNOW COVER AND A RELATIVELY MILD AIRMASS SHOULD ALLOW FOR A SOMEWHAT
DEEPER MIXED LAYER IN THE AFTERNOONS (MORE ROOM FOR THE POLLUTANTS
TO RISE UP AWAY FROM THE SURFACE).

ON WEDNESDAY AND WEDNESDAY NIGHT (CHRISTMAS EVE), ATTENTION TURNS TO
THE POTENTIAL FOR AN INSIDE SLIDER-TYPE SYSTEM. THESE TYPES OF
SYSTEMS ARE OF SPECIAL INTEREST TO LOCATIONS EAST OF THE SIERRA IN
WESTERN NEVADA AS THEY CAN BRING SOME OF THE HEAVIEST SNOWFALL
RATES/AMOUNTS SEEN IN THE WESTERN GREAT BASIN (DESPITE THEIR
TYPICALLY LIMITED MOISTURE).

TO TALK FIRST ABOUT WHAT WE FEEL CONFIDENT IN, THERE WILL BE A
STRONG COLD FRONT THAT MOVES THROUGH CHRISTMAS EVE INTO VERY EARLY
CHRISTMAS MORNING. CHRISTMAS DAY LOOKS CHILLY WITH HIGH TEMPERATURES
FALLING TO AT LEAST 5-10 DEGREES BELOW AVERAGE (A 15-25 DEGREE DROP
FROM WEDNESDAY`S HIGH). ALSO, GIVEN SUCH A STRONG FROPA AND GOOD
MIXING PRIOR TO THE FRONTAL PASSAGE, IT IS LIKELY TO BE QUITE BREEZY
CHRISTMAS EVE, ESPECIALLY BY AFTERNOON AND EVENING.

THE REAL UNCERTAINTIES WILL BE IN WHETHER WE GET A BAND OF MODERATE
TO HEAVY SNOW ALONG THE FRONT OR NOTHING MORE THAN ISOLATED TO
SCATTERED LIGHT SNOW (OR RAIN CHANGING QUICKLY TO SNOW) SHOWERS. A
SECOND UNCERTAINTY IS JUST HOW COLD IT WILL GET BEHIND THE FRONT ON
THURSDAY. A LOT OF THAT DEPENDS ON SNOWFALL, AS A COUPLE INCHES OF
SNOW ON CHRISTMAS EVE WOULD KNOCK HIGHS ON CHRISTMAS DOWN FROM THE
30S TO THE 20S FOR MOST AREAS.

RIGHT NOW, MODELS ARE FIGHTING BETWEEN AN UPPER LOW OVER FAR WESTERN
NEVADA (BULLSEYE FOR HEAVY SNOW) OR A GLANCING BLOW WITH AN UPPER
LOW OVER IDAHO (MAYBE A FEW LIGHT SHOWERS). THERE ARE SIGNIFICANT
IMPACTS IF THE WESTERN SOLUTION VERIFIES AND IT WILL PROBABLY TAKE
UNTIL EARLY NEXT WEEK FOR MODELS TO ZERO IN ON A SOLUTION SO STAY
TUNED. SNYDER

&&

.AVIATION...
RIDGE OF HIGH PRESSURE BUILDS OVER THE REGION WITH DRY CONDITIONS
THROUGH LATE TONIGHT. FOG IS NOT OUT OF THE QUESTION FOR THE MARTIS
VALLEY/KTRK TONIGHT, ALTHOUGH IT WILL LIKELY REMAIN PATCHY WITH
INCREASING CLOUDS AND FLOW ALOFT TO DISRUPT ITS FORMATION. FARTHER
SOUTH NEAR CROWLEY AND MONO LAKES (HWY 395) LOW CLOUDS AND FREEZING
FOG ARE LIKELY AGAIN TONIGHT AS CLOUDS TAKE LONGER TO INCREASE IN
THAT AREA.

A COLD FRONT MOVES INTO THE REGION ON FRIDAY. SOUTHWEST-WEST WINDS
WILL INCREASE WITH SOME TURBULENCE DOWNWIND OF THE SIERRA,
ESPECIALLY THROUGH AROUND MIDDAY AHEAD OF THE FRONT. AS FAR AS
PRECIPITATION, IT LOOKS MAINLY CONFINED TO THE SIERRA AND NEVADA
NORTH OF A PYRAMID LAKE-KWMC LINE. WITH FAIRLY LOW SNOW LEVELS, IFR
CONDITIONS WITH WIDESPREAD TERRAIN OBSCURATION LIKELY IN THE SIERRA
ALTHOUGH SNOWFALL LOOKS TO REMAIN LIGHT (A FEW INCHES). FOR WESTERN
NEVADA, HIGHER TERRAIN OBSCURATION IN RAIN/SNOW SHOWERS WILL BE THE
MAIN IMPACT. SNYDER

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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











000
FXUS65 KREV 182328
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
328 PM PST THU DEC 18 2014

.SYNOPSIS...
A COUPLE WEAK STORMS WILL BRING CHANCES FOR RAIN AND SNOW FRIDAY
THROUGH SATURDAY MAINLY NORTH OF HIGHWAY 50. HIGH PRESSURE WILL
THEN BUILD SUNDAY THROUGH THE FIRST PART OF NEXT WEEK. A COOLING
TREND IS POSSIBLE LATE NEXT WEEK.

&&

.SHORT TERM...
FEW CHANGES MADE OVERALL WITH THE MODELS IN REASONABLY GOOD
AGREEMENT WITH THE WEAKENING SYSTEM ARRIVING FRIDAY MORNING.
EXPECT ANOTHER MILD NIGHT TONIGHT WITH SOME ABUNDANT MID AND HIGH
CLOUD COVER AHEAD OF THE SYSTEM.

THE BULK OF THE SYSTEM ARRIVES FRIDAY MORNING AND ALL THE MODELS
SHOWING IT SPLITTING AND WEAKENING AS IT ARRIVES. WHAT LITTLE JET
ENERGY IS LEFT IS FORECAST TO REMAIN IN OREGON WITH ONLY THE WEAK
LEFT OVER LOW-LEVEL FRONT MAKING IT AS FAR SOUTH AS I-80. THERE IS
ENOUGH MOISTURE TO SQUEEZE OUT SOME RAIN AND SNOW OVER THE SIERRA
FROM TAHOE NORTH. EXPECT LITTLE SPILLING OVER INTO WESTERN NEVADA
EXCEPT NEAR THE OREGON BORDER CLOSER TO THE FORCING WITH THE WEAK
UPPER JET. SNOW LEVELS WILL REMAIN NEAR 6000-6500 FEET AROUND I-80
AND 4500-5000 FEET NEAR THE OREGON BORDER. LIGHT SNOW AMOUNTS OF
UP TO A COUPLE INCHES ARE POSSIBLE ABOVE THIS LEVEL WITH HIGHER
AMOUNTS TO 6 INCHES NEAR THE SIERRA CREST.

AS THIS SYSTEM PULLS AWAY FRIDAY NIGHT, EXPECT A DECREASING CHANCE
OF SHOWERS BUT CLOUD COVER WILL CONTINUE TO KEEP OVERNIGHT TEMPS
MILD. ON SATURDAY, THE PACIFIC JET REORGANIZES AND IS DIRECTED
INTO WASHINGTON. HOWEVER, A MOIST PACIFIC PLUME WILL EXTEND SOUTH
INTO NORTHERN CALIFORNIA AND NEVADA. SOME DECENT ISENTROPIC LIFT
IS SHOWN WITH WARM AIR ADVECTION SATURDAY. THE BEST CHANCE WILL
OCCUR NEAR THE OREGON BORDER WITH CHANCES TAPERING TO NOTHING
SOUTH OF HIGHWAY 50. SNOW LEVELS WITH THIS ONE WILL BE MORE
PROBLEMATIC AS MODEL SOUNDING SHOW ISOTHERMAL PROFILES HOVERING
NEAR FREEZING. THIS COULD KEEP SNOW LEVELS NEAR THE VALLEY FLOORS
IN THE SURPRISE VALLEY BEFORE RAPIDLY RISING TO ABOVE 8000 FEET
WITH THE PASSAGE OF THE WARM FRONT.

AFTER THIS WAVE PASSES SATURDAY NIGHT, THE RIDGE WILL AMPLIFY JUST
OFF THE COAST BRINGING A WARMING AND DRYING TREND. WITH ABUNDANT
CLOUD COVER AGAIN SATURDAY NIGHT BEFORE THE SYSTEM EXITS, TEMPS
COULD AGAIN BE MILD. WARM TEMPS COULD FOLLOW SUNDAY THAT MAY BE
10-15 DEGREES ABOVE NORMAL AS RIDGE TOP (10,000 FOOT) TEMPS RISE
ABOVE FREEZING. WALLMANN

.LONG TERM...MONDAY THROUGH THURSDAY/CHRISTMAS DAY...
AN UPPER RIDGE WILL RULE THE EASTERN SIERRA AND WESTERN NEVADA
MONDAY AND TUESDAY. THIS WILL BRING LIGHT VALLEY WINDS AND HIGH
TEMPERATURES NEAR TO SLIGHTLY ABOVE (4-7 DEGREES) AVERAGE. THE LIGHT
WINDS AND STABLE CONDITIONS WILL ALLOW POLLUTANT BUILDUP FOR THE
VALLEYS, ESPECIALLY FOR THE RENO-SPARKS AREA. HOWEVER, THE LACK OF
SNOW COVER AND A RELATIVELY MILD AIRMASS SHOULD ALLOW FOR A SOMEWHAT
DEEPER MIXED LAYER IN THE AFTERNOONS (MORE ROOM FOR THE POLLUTANTS
TO RISE UP AWAY FROM THE SURFACE).

ON WEDNESDAY AND WEDNESDAY NIGHT (CHRISTMAS EVE), ATTENTION TURNS TO
THE POTENTIAL FOR AN INSIDE SLIDER-TYPE SYSTEM. THESE TYPES OF
SYSTEMS ARE OF SPECIAL INTEREST TO LOCATIONS EAST OF THE SIERRA IN
WESTERN NEVADA AS THEY CAN BRING SOME OF THE HEAVIEST SNOWFALL
RATES/AMOUNTS SEEN IN THE WESTERN GREAT BASIN (DESPITE THEIR
TYPICALLY LIMITED MOISTURE).

TO TALK FIRST ABOUT WHAT WE FEEL CONFIDENT IN, THERE WILL BE A
STRONG COLD FRONT THAT MOVES THROUGH CHRISTMAS EVE INTO VERY EARLY
CHRISTMAS MORNING. CHRISTMAS DAY LOOKS CHILLY WITH HIGH TEMPERATURES
FALLING TO AT LEAST 5-10 DEGREES BELOW AVERAGE (A 15-25 DEGREE DROP
FROM WEDNESDAY`S HIGH). ALSO, GIVEN SUCH A STRONG FROPA AND GOOD
MIXING PRIOR TO THE FRONTAL PASSAGE, IT IS LIKELY TO BE QUITE BREEZY
CHRISTMAS EVE, ESPECIALLY BY AFTERNOON AND EVENING.

THE REAL UNCERTAINTIES WILL BE IN WHETHER WE GET A BAND OF MODERATE
TO HEAVY SNOW ALONG THE FRONT OR NOTHING MORE THAN ISOLATED TO
SCATTERED LIGHT SNOW (OR RAIN CHANGING QUICKLY TO SNOW) SHOWERS. A
SECOND UNCERTAINTY IS JUST HOW COLD IT WILL GET BEHIND THE FRONT ON
THURSDAY. A LOT OF THAT DEPENDS ON SNOWFALL, AS A COUPLE INCHES OF
SNOW ON CHRISTMAS EVE WOULD KNOCK HIGHS ON CHRISTMAS DOWN FROM THE
30S TO THE 20S FOR MOST AREAS.

RIGHT NOW, MODELS ARE FIGHTING BETWEEN AN UPPER LOW OVER FAR WESTERN
NEVADA (BULLSEYE FOR HEAVY SNOW) OR A GLANCING BLOW WITH AN UPPER
LOW OVER IDAHO (MAYBE A FEW LIGHT SHOWERS). THERE ARE SIGNIFICANT
IMPACTS IF THE WESTERN SOLUTION VERIFIES AND IT WILL PROBABLY TAKE
UNTIL EARLY NEXT WEEK FOR MODELS TO ZERO IN ON A SOLUTION SO STAY
TUNED. SNYDER


.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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








000
FXUS65 KREV 182328
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
328 PM PST THU DEC 18 2014

.SYNOPSIS...
A COUPLE WEAK STORMS WILL BRING CHANCES FOR RAIN AND SNOW FRIDAY
THROUGH SATURDAY MAINLY NORTH OF HIGHWAY 50. HIGH PRESSURE WILL
THEN BUILD SUNDAY THROUGH THE FIRST PART OF NEXT WEEK. A COOLING
TREND IS POSSIBLE LATE NEXT WEEK.

&&

.SHORT TERM...
FEW CHANGES MADE OVERALL WITH THE MODELS IN REASONABLY GOOD
AGREEMENT WITH THE WEAKENING SYSTEM ARRIVING FRIDAY MORNING.
EXPECT ANOTHER MILD NIGHT TONIGHT WITH SOME ABUNDANT MID AND HIGH
CLOUD COVER AHEAD OF THE SYSTEM.

THE BULK OF THE SYSTEM ARRIVES FRIDAY MORNING AND ALL THE MODELS
SHOWING IT SPLITTING AND WEAKENING AS IT ARRIVES. WHAT LITTLE JET
ENERGY IS LEFT IS FORECAST TO REMAIN IN OREGON WITH ONLY THE WEAK
LEFT OVER LOW-LEVEL FRONT MAKING IT AS FAR SOUTH AS I-80. THERE IS
ENOUGH MOISTURE TO SQUEEZE OUT SOME RAIN AND SNOW OVER THE SIERRA
FROM TAHOE NORTH. EXPECT LITTLE SPILLING OVER INTO WESTERN NEVADA
EXCEPT NEAR THE OREGON BORDER CLOSER TO THE FORCING WITH THE WEAK
UPPER JET. SNOW LEVELS WILL REMAIN NEAR 6000-6500 FEET AROUND I-80
AND 4500-5000 FEET NEAR THE OREGON BORDER. LIGHT SNOW AMOUNTS OF
UP TO A COUPLE INCHES ARE POSSIBLE ABOVE THIS LEVEL WITH HIGHER
AMOUNTS TO 6 INCHES NEAR THE SIERRA CREST.

AS THIS SYSTEM PULLS AWAY FRIDAY NIGHT, EXPECT A DECREASING CHANCE
OF SHOWERS BUT CLOUD COVER WILL CONTINUE TO KEEP OVERNIGHT TEMPS
MILD. ON SATURDAY, THE PACIFIC JET REORGANIZES AND IS DIRECTED
INTO WASHINGTON. HOWEVER, A MOIST PACIFIC PLUME WILL EXTEND SOUTH
INTO NORTHERN CALIFORNIA AND NEVADA. SOME DECENT ISENTROPIC LIFT
IS SHOWN WITH WARM AIR ADVECTION SATURDAY. THE BEST CHANCE WILL
OCCUR NEAR THE OREGON BORDER WITH CHANCES TAPERING TO NOTHING
SOUTH OF HIGHWAY 50. SNOW LEVELS WITH THIS ONE WILL BE MORE
PROBLEMATIC AS MODEL SOUNDING SHOW ISOTHERMAL PROFILES HOVERING
NEAR FREEZING. THIS COULD KEEP SNOW LEVELS NEAR THE VALLEY FLOORS
IN THE SURPRISE VALLEY BEFORE RAPIDLY RISING TO ABOVE 8000 FEET
WITH THE PASSAGE OF THE WARM FRONT.

AFTER THIS WAVE PASSES SATURDAY NIGHT, THE RIDGE WILL AMPLIFY JUST
OFF THE COAST BRINGING A WARMING AND DRYING TREND. WITH ABUNDANT
CLOUD COVER AGAIN SATURDAY NIGHT BEFORE THE SYSTEM EXITS, TEMPS
COULD AGAIN BE MILD. WARM TEMPS COULD FOLLOW SUNDAY THAT MAY BE
10-15 DEGREES ABOVE NORMAL AS RIDGE TOP (10,000 FOOT) TEMPS RISE
ABOVE FREEZING. WALLMANN

.LONG TERM...MONDAY THROUGH THURSDAY/CHRISTMAS DAY...
AN UPPER RIDGE WILL RULE THE EASTERN SIERRA AND WESTERN NEVADA
MONDAY AND TUESDAY. THIS WILL BRING LIGHT VALLEY WINDS AND HIGH
TEMPERATURES NEAR TO SLIGHTLY ABOVE (4-7 DEGREES) AVERAGE. THE LIGHT
WINDS AND STABLE CONDITIONS WILL ALLOW POLLUTANT BUILDUP FOR THE
VALLEYS, ESPECIALLY FOR THE RENO-SPARKS AREA. HOWEVER, THE LACK OF
SNOW COVER AND A RELATIVELY MILD AIRMASS SHOULD ALLOW FOR A SOMEWHAT
DEEPER MIXED LAYER IN THE AFTERNOONS (MORE ROOM FOR THE POLLUTANTS
TO RISE UP AWAY FROM THE SURFACE).

ON WEDNESDAY AND WEDNESDAY NIGHT (CHRISTMAS EVE), ATTENTION TURNS TO
THE POTENTIAL FOR AN INSIDE SLIDER-TYPE SYSTEM. THESE TYPES OF
SYSTEMS ARE OF SPECIAL INTEREST TO LOCATIONS EAST OF THE SIERRA IN
WESTERN NEVADA AS THEY CAN BRING SOME OF THE HEAVIEST SNOWFALL
RATES/AMOUNTS SEEN IN THE WESTERN GREAT BASIN (DESPITE THEIR
TYPICALLY LIMITED MOISTURE).

TO TALK FIRST ABOUT WHAT WE FEEL CONFIDENT IN, THERE WILL BE A
STRONG COLD FRONT THAT MOVES THROUGH CHRISTMAS EVE INTO VERY EARLY
CHRISTMAS MORNING. CHRISTMAS DAY LOOKS CHILLY WITH HIGH TEMPERATURES
FALLING TO AT LEAST 5-10 DEGREES BELOW AVERAGE (A 15-25 DEGREE DROP
FROM WEDNESDAY`S HIGH). ALSO, GIVEN SUCH A STRONG FROPA AND GOOD
MIXING PRIOR TO THE FRONTAL PASSAGE, IT IS LIKELY TO BE QUITE BREEZY
CHRISTMAS EVE, ESPECIALLY BY AFTERNOON AND EVENING.

THE REAL UNCERTAINTIES WILL BE IN WHETHER WE GET A BAND OF MODERATE
TO HEAVY SNOW ALONG THE FRONT OR NOTHING MORE THAN ISOLATED TO
SCATTERED LIGHT SNOW (OR RAIN CHANGING QUICKLY TO SNOW) SHOWERS. A
SECOND UNCERTAINTY IS JUST HOW COLD IT WILL GET BEHIND THE FRONT ON
THURSDAY. A LOT OF THAT DEPENDS ON SNOWFALL, AS A COUPLE INCHES OF
SNOW ON CHRISTMAS EVE WOULD KNOCK HIGHS ON CHRISTMAS DOWN FROM THE
30S TO THE 20S FOR MOST AREAS.

RIGHT NOW, MODELS ARE FIGHTING BETWEEN AN UPPER LOW OVER FAR WESTERN
NEVADA (BULLSEYE FOR HEAVY SNOW) OR A GLANCING BLOW WITH AN UPPER
LOW OVER IDAHO (MAYBE A FEW LIGHT SHOWERS). THERE ARE SIGNIFICANT
IMPACTS IF THE WESTERN SOLUTION VERIFIES AND IT WILL PROBABLY TAKE
UNTIL EARLY NEXT WEEK FOR MODELS TO ZERO IN ON A SOLUTION SO STAY
TUNED. SNYDER


.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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







000
FXUS65 KREV 181119
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
319 AM PST THU DEC 18 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE REGION TODAY BEFORE ANOTHER
WEAK STORM SYSTEM BRINGS CHANCES FOR RAIN AND SNOW FRIDAY THROUGH
SATURDAY. HIGH PRESSURE WILL THEN BUILD SUNDAY THROUGH THE FIRST
PART OF NEXT WEEK.

&&

.SHORT TERM...
WEAK STORM SYSTEM ACROSS NORTHERN CALIFORNIA TONIGHT HAS FALLEN
APART AS IT APPROACHES THE SIERRA. FORECAST MODELS AS WELL AS
OBSERVATIONS INDICATE THAT LITTLE TO NO PRECIPITATION IS LIKELY TO
OCCUR ALONG OR EAST OF THE CREST. SNOWFALL AMOUNTS MAY REACH UP
TO 2 INCHES ALONG THE SIERRA CREST, IF WE ARE LUCKY, BUT OTHERWISE
ONLY WEAK SNOW SHOWERS ARE EXPECTED. WHILE AMOUNTS ARE EXPECTED
TO BE LIGHT, TRAVEL MAY BECOME SLICK OVERNIGHT INTO THIS MORNING
FOR THE SIERRA PASSES, ESPECIALLY DONNER AND ECHO SUMMITS AND
ALONG HIGHWAY 89. THIS WAVE MOVES EAST THIS AFTERNOON WITH A FEW
LINGERING SHOWERS DURING THE DAY. A BRIEF PERIOD OF RIDGING
DEVELOPS LATE THIS EVENING.

THE NEXT SYSTEM DROPS INTO THE REGION ON FRIDAY AND SATURDAY WITH A
WEAK COLD FRONT PUSHING ACROSS THE SIERRA AND WESTERN NEVADA LATE
FRIDAY MORNING. THE BEST DYNAMICS AND FORCING WITH THIS SYSTEM WILL
REMAIN NORTH OF NEVADA, ACROSS OREGON, BUT THE SOUTHERN PORTION OF A
WEAK COLD FRONT WILL BRUSH THROUGH NORTHERN NEVADA. PRECIPITATION
WILL BEGIN ACROSS NORTHEAST CALIFORNIA INTO NORTHERN WASHOE COUNTY
MID MORNING FRIDAY AND THEN SAG FURTHER SOUTH WITH THE WEAKENING
FRONT INTO THE CENTRAL BASIN AND RANGE AND TO THE INTERSTATE 80
CORRIDOR. FORECAST MODELS CONTINUE TO SHADOW MUCH OF THE SIERRA
FRONT INCLUDING RENO/CARSON CITY, BUT LEFT IN LOW CHANCES FOR
SHOWERS DURING FRIDAY AFTERNOON. ALTHOUGH THE SYSTEM QUICKLY EXITS
EAST ON FRIDAY EVENING, THERE IS QUITE A BIT OF MOISTURE AND UPSLOPE
FLOW BEHIND IT THAT MAY ALLOW SHOWERS TO CONTINUE ALONG THE SIERRA
FROM TAHOE NORTHWARD INTO NORTHERN LASSEN AND NORTHERN WASHOE
COUNTIES. SNOW LEVELS WILL BE AROUND 4500-5500 FEET NORTH OF HIGHWAY
50 WITH 5500-6500 FEET SOUTH OF THERE. TRAVEL IMPACTS ALONG WITH
SLICK ROADS WILL REMAIN A POSSIBILITY AS SHOWERS MOVE ACROSS THE
REGION.

BY SATURDAY AND SUNDAY A DIRTY RIDGE BUILDS INTO THE WEST WITH WARM
AIR ADVECTION PRECIPITATION POSSIBLE ACROSS NORTHERN CA/NV. THE JET
RIDING OVER THE TOP OF THE RIDGE MAY PRODUCE ENOUGH LIFT ALONG WITH
THE MOISTURE TO PRODUCE SOME SHOWERS ACROSS THE SIERRA, BUT
DIFFERENCES IN JET PLACEMENT BETWEEN THE MODELS MAKE IT DIFFICULT TO
NAIL DOWN WHERE BEST PRECIPITATION CHANCES WILL BE AT THIS TIME.
KEPT THE SLIGHT CHANCES FOR PRECIPITATION AREA WIDE TO COVER THE
POSSIBILITY OF SHOWERS AS FAR SOUTH AS MONO AND MINERAL COUNTIES.
WEISHAHN

.LONG TERM...SUNDAY THROUGH THURSDAY (CHRISTMAS DAY)...

THE UPPER LEVEL RIDGE STRENGTHENS OVER CALIFORNIA SUNDAY THROUGH
TUESDAY. THIS RIDGE LOOKS "DIRTY" WITH ABUNDANT CLOUDS/MOISTURE
NORTH OF RENO. WARM AIR ADVECTION WILL WARM UP TEMPERATURES IN THE
SIERRA, ALTHOUGH LIGHT WINDS AND LOW SUN ANGLES WILL LIMIT MIXING IN
THE LOWER VALLEYS OF WESTERN NEVADA EARLY NEXT WEEK WITH INVERSIONS
LIKELY. THIS MAY LEAD TO DEGRADED AIR QUALITY THROUGH SUNDAY THROUGH
WEDNESDAY.

THE 00Z GFS/ECMWF/GEM AND ENSEMBLES CONTINUE SHOW AN INSIDE SLIDER
DROPPING THROUGH THE PAC NW AND INTO THE GREAT BASIN LATE ON
CHRISTMAS EVE AND POSSIBLY INTO CHRISTMAS MORNING. THIS IS THE THIRD
DAY IN A ROW THAT WE`VE SEEN THE ECMWF SHOW THIS FEATURE ON
CHRISTMAS EVE NIGHT, VERY GOOD RUN-TO-RUN CONSISTENCY FOR 7 DAYS
OUT. THE GFS ENSEMBLES STILL SHOW QUITE A BIT OF SPREAD IN THE
FRONTAL TIMING AND EAST-TO-WEST TRACK OF PRECIP. NONETHELESS, THE
DECENT MODEL AGREEMENT THIS FAR OUT IS LEADING TO A MODERATE
FORECAST CONFIDENCE OF A STRONG FRONTAL PASSAGE LATE TUESDAY
(CHRISTMAS EVE) WITH MUCH COLDER TEMPERATURES ON CHRISTMAS DAY.
WE`LL HAVE TO WATCH THIS COLD FRONT VERY CLOSELY FOR POTENTIAL OF
SEEING SNOW ON THE VALLEY FLOORS ON CHRISTMAS EVE NIGHT. HOON

&&

.AVIATION...

RIDGE OF HIGH PRESSURE BUILDS OVER THE REGION WITH DRY CONDITIONS
THROUGH TONIGHT. ANOTHER COLD FRONT MOVES THROUGH THE REGION FRIDAY
WITH POTENTIAL FOR MOUNTAIN SNOW AND REDUCTIONS TO CIG/VIS. HOON

&&


.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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







000
FXUS65 KREV 181119
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
319 AM PST THU DEC 18 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE REGION TODAY BEFORE ANOTHER
WEAK STORM SYSTEM BRINGS CHANCES FOR RAIN AND SNOW FRIDAY THROUGH
SATURDAY. HIGH PRESSURE WILL THEN BUILD SUNDAY THROUGH THE FIRST
PART OF NEXT WEEK.

&&

.SHORT TERM...
WEAK STORM SYSTEM ACROSS NORTHERN CALIFORNIA TONIGHT HAS FALLEN
APART AS IT APPROACHES THE SIERRA. FORECAST MODELS AS WELL AS
OBSERVATIONS INDICATE THAT LITTLE TO NO PRECIPITATION IS LIKELY TO
OCCUR ALONG OR EAST OF THE CREST. SNOWFALL AMOUNTS MAY REACH UP
TO 2 INCHES ALONG THE SIERRA CREST, IF WE ARE LUCKY, BUT OTHERWISE
ONLY WEAK SNOW SHOWERS ARE EXPECTED. WHILE AMOUNTS ARE EXPECTED
TO BE LIGHT, TRAVEL MAY BECOME SLICK OVERNIGHT INTO THIS MORNING
FOR THE SIERRA PASSES, ESPECIALLY DONNER AND ECHO SUMMITS AND
ALONG HIGHWAY 89. THIS WAVE MOVES EAST THIS AFTERNOON WITH A FEW
LINGERING SHOWERS DURING THE DAY. A BRIEF PERIOD OF RIDGING
DEVELOPS LATE THIS EVENING.

THE NEXT SYSTEM DROPS INTO THE REGION ON FRIDAY AND SATURDAY WITH A
WEAK COLD FRONT PUSHING ACROSS THE SIERRA AND WESTERN NEVADA LATE
FRIDAY MORNING. THE BEST DYNAMICS AND FORCING WITH THIS SYSTEM WILL
REMAIN NORTH OF NEVADA, ACROSS OREGON, BUT THE SOUTHERN PORTION OF A
WEAK COLD FRONT WILL BRUSH THROUGH NORTHERN NEVADA. PRECIPITATION
WILL BEGIN ACROSS NORTHEAST CALIFORNIA INTO NORTHERN WASHOE COUNTY
MID MORNING FRIDAY AND THEN SAG FURTHER SOUTH WITH THE WEAKENING
FRONT INTO THE CENTRAL BASIN AND RANGE AND TO THE INTERSTATE 80
CORRIDOR. FORECAST MODELS CONTINUE TO SHADOW MUCH OF THE SIERRA
FRONT INCLUDING RENO/CARSON CITY, BUT LEFT IN LOW CHANCES FOR
SHOWERS DURING FRIDAY AFTERNOON. ALTHOUGH THE SYSTEM QUICKLY EXITS
EAST ON FRIDAY EVENING, THERE IS QUITE A BIT OF MOISTURE AND UPSLOPE
FLOW BEHIND IT THAT MAY ALLOW SHOWERS TO CONTINUE ALONG THE SIERRA
FROM TAHOE NORTHWARD INTO NORTHERN LASSEN AND NORTHERN WASHOE
COUNTIES. SNOW LEVELS WILL BE AROUND 4500-5500 FEET NORTH OF HIGHWAY
50 WITH 5500-6500 FEET SOUTH OF THERE. TRAVEL IMPACTS ALONG WITH
SLICK ROADS WILL REMAIN A POSSIBILITY AS SHOWERS MOVE ACROSS THE
REGION.

BY SATURDAY AND SUNDAY A DIRTY RIDGE BUILDS INTO THE WEST WITH WARM
AIR ADVECTION PRECIPITATION POSSIBLE ACROSS NORTHERN CA/NV. THE JET
RIDING OVER THE TOP OF THE RIDGE MAY PRODUCE ENOUGH LIFT ALONG WITH
THE MOISTURE TO PRODUCE SOME SHOWERS ACROSS THE SIERRA, BUT
DIFFERENCES IN JET PLACEMENT BETWEEN THE MODELS MAKE IT DIFFICULT TO
NAIL DOWN WHERE BEST PRECIPITATION CHANCES WILL BE AT THIS TIME.
KEPT THE SLIGHT CHANCES FOR PRECIPITATION AREA WIDE TO COVER THE
POSSIBILITY OF SHOWERS AS FAR SOUTH AS MONO AND MINERAL COUNTIES.
WEISHAHN

.LONG TERM...SUNDAY THROUGH THURSDAY (CHRISTMAS DAY)...

THE UPPER LEVEL RIDGE STRENGTHENS OVER CALIFORNIA SUNDAY THROUGH
TUESDAY. THIS RIDGE LOOKS "DIRTY" WITH ABUNDANT CLOUDS/MOISTURE
NORTH OF RENO. WARM AIR ADVECTION WILL WARM UP TEMPERATURES IN THE
SIERRA, ALTHOUGH LIGHT WINDS AND LOW SUN ANGLES WILL LIMIT MIXING IN
THE LOWER VALLEYS OF WESTERN NEVADA EARLY NEXT WEEK WITH INVERSIONS
LIKELY. THIS MAY LEAD TO DEGRADED AIR QUALITY THROUGH SUNDAY THROUGH
WEDNESDAY.

THE 00Z GFS/ECMWF/GEM AND ENSEMBLES CONTINUE SHOW AN INSIDE SLIDER
DROPPING THROUGH THE PAC NW AND INTO THE GREAT BASIN LATE ON
CHRISTMAS EVE AND POSSIBLY INTO CHRISTMAS MORNING. THIS IS THE THIRD
DAY IN A ROW THAT WE`VE SEEN THE ECMWF SHOW THIS FEATURE ON
CHRISTMAS EVE NIGHT, VERY GOOD RUN-TO-RUN CONSISTENCY FOR 7 DAYS
OUT. THE GFS ENSEMBLES STILL SHOW QUITE A BIT OF SPREAD IN THE
FRONTAL TIMING AND EAST-TO-WEST TRACK OF PRECIP. NONETHELESS, THE
DECENT MODEL AGREEMENT THIS FAR OUT IS LEADING TO A MODERATE
FORECAST CONFIDENCE OF A STRONG FRONTAL PASSAGE LATE TUESDAY
(CHRISTMAS EVE) WITH MUCH COLDER TEMPERATURES ON CHRISTMAS DAY.
WE`LL HAVE TO WATCH THIS COLD FRONT VERY CLOSELY FOR POTENTIAL OF
SEEING SNOW ON THE VALLEY FLOORS ON CHRISTMAS EVE NIGHT. HOON

&&

.AVIATION...

RIDGE OF HIGH PRESSURE BUILDS OVER THE REGION WITH DRY CONDITIONS
THROUGH TONIGHT. ANOTHER COLD FRONT MOVES THROUGH THE REGION FRIDAY
WITH POTENTIAL FOR MOUNTAIN SNOW AND REDUCTIONS TO CIG/VIS. HOON

&&


.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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








000
FXUS65 KREV 180620
AFDREV

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RENO NV
1020 PM PST WED DEC 17 2014

.UPDATE...
ALREADY WEAK UPPER FORCING WAS WANING AND PUSHING THROUGH WESTERN
NV THIS EVENING AS BAND OF RAIN AND SNOW LAGGED BEHIND OVER CA.
MOST MODELS HAVE BACKED WAY OFF ON RAIN AND SNOW FOR AREAS EAST OF
THE SIERRA AS A RESULT OF THE LATEST TRENDS. THE BAND OF RAIN AND
SNOW, IF IT CAN HOLD TOGETHER, MAY REACH THE CREST WITH SOME LIGHT
SNOW POSSIBLE IN THE TAHOE BASIN AND ALONG HIGHWAY 89 NORTH OF
TRUCKEE, BUT SNOWFALL AMOUNTS ARE GOING TO BE LIGHT. WE UPDATED TO
SIGNIFICANTLY LOWER POPS ACROSS WESTERN NV AND EVEN PARTS OF THE
EASTERN SIERRA. SNOWFALL AMOUNTS UP TO 2 INCHES ARE POSSIBLE WEST
OF HIGHWAY 89 WITH AN INCH OR LESS AT KTVL/KTRK OVERNIGHT. WHILE
AMOUNTS WILL BE LIGHT, TRAVEL MAY BECOME SLICK OVERNIGHT INTO
THURSDAY MORNING FOR AREA PASSES, ESPECIALLY DONNER AND ECHO
SUMMITS, AND ALONG HIGHWAY 89. A FEW FLURRIES MAY VISIT THE
HIGHWAY 395 CORRIDOR. HOHMANN

&&

.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE REGION THURSDAY BEFORE ANOTHER
WEAK STORM SYSTEM BRINGS ANOTHER CHANCE OF RAIN AND SNOW FRIDAY
THROUGH SATURDAY. HIGH PRESSURE WILL THEN BUILD SUNDAY THROUGH THE
FIRST PART OF NEXT WEEK.

&&

.PREVIOUS DISCUSSION... /ISSUED 722 PM PST WED DEC 17 2014/

SYNOPSIS...

A WEAK AREA OF LOW PRESSURE MOVES ACROSS NORTHERN CALIFORNIA AND
WESTERN NEVADA TONIGHT AND EARLY THURSDAY. THIS LOW PRESSURE
SHOULD BRING ANOTHER ROUND OF LIGHT SNOW TO AREAS NORTH OF HIGHWAY
50 AND ALONG THE SIERRA CREST IN MONO COUNTY. ANOTHER SYSTEM WILL
IMPACT THE SAME AREAS FRIDAY WITH ANOTHER ROUND OF LIGHT SNOW. SLICK
AND SNOW COVERED ROADS ARE LIKELY FOR THE SIERRA PASSES THROUGH
FRIDAY. A FEW SLICK SPOTS ARE POSSIBLE IN THE LOWER VALLEYS AS WELL
THAT COULD IMPACT THE MORNING COMMUTE THURSDAY.

SHORT TERM...
NEXT WAVE IS MOVING TOWARD THE COAST NOW AND SHOULD IMPACT OUR
FORECAST AREA TONIGHT. THIS DOES NOT APPEAR TO BE AN OVERLY STRONG
WAVE...BUT THERE IS ENOUGH MOISTURE WITH IT TO PRODUCE LIGHT PCPN.
FORECAST MODELS DO NOT SHOW AN OVERWHELMING AMOUNT OF FORCING WITH
THIS SYSTEM. THERE IS A WARM AIR ADVECTION SIGNATURE WITH THE SYSTEM
THAT...COUPLED WITH FAIRLY DEEP MOISTURE...SHOULD PUSH PCPN OVER THE
SIERRA INTO WESTERN NEVADA OVERNIGHT.

THE BEST CHANCE FOR PCPN IN THE EVENING SHOULD BE IN NORTHEAST CA
FROM ABOUT THE TAHOE BASIN NORTHWARD. THEN THE PCPN CHANCES SPREAD
EAST AND SOUTH THROUGH THE OVERNIGHT HOURS. WITH WARM AIR ADVECTION
SYSTEMS LIKE THIS THE AMOUNT OF PCPN DOES NOT TEND TO BE VERY HIGH
OR DRIVEN MUCH BY TERRAIN INFLUENCES. THUS...IT IS NOT OUT OF THE
QUESTION FOR AREAS EAST OF THE SIERRA TO GET ABOUT AS MUCH AS
POINTS IN THE SIERRA AND FAR NORTHEAST CA. SNOW LEVELS COULD BE
DOWN TO EVEN THE LOWEST VALLEY FLOORS IN THIS WARM AIR ADVECTION
AS WELL. FORECAST SOUNDINGS EAST OF THE SIERRA SHOW A DROP TO NEAR
4500 FEET FOR THE SNOW LEVELS LATE TONIGHT.

SO...WHAT DOES THIS MEAN FOR OVERNIGHT? HIGH POPS AND LOW QPF WITH
MAYBE UP TO AN INCH OF SNOW FOR AREAS OF WESTERN NEVADA. IN THE
TAHOE BASIN...NORTHEAST CA AND THE HIGHER ELEVATIONS OF MONO
COUNTY...SNOW AMOUNTS SHOULD BE AN INCH OR TWO EXCEPT IN THE
HIGHEST ELEVATIONS WHERE UP TO 4 INCHES IS POSSIBLE. SO...WE WILL
NOT PLAN ANY ADVISORIES AT THIS TIME...BUT BE ADVISED THAT EVEN AN
INCH OF SNOW COULD RESULT IN SLICK ROADS FOR THE MORNING COMMUTE.
BE PREPARED FOR A FEW TRAVEL DELAYS FOR THE THURSDAY MORNING
COMMUTE FOR EASTERN CA AND FAR WESTERN NV.

THIS WAVE MOVES EAST THURSDAY AFTERNOON WITH A FEW LINGERING
SHOWERS DURING THE DAY. A BRIEF PERIOD OF RIDGING DEVELOPS LATE
THURSDAY EVENING...BUT THIS IS QUICKLY REPLACED BY ANOTHER WAVE
MOVING ACROSS THE NORTHERN FORECAST AREA FRIDAY. 20

FRIDAY AND SATURDAY...
ANOTHER WAVE MOVES ACROSS NORTHERN CA/NV FRIDAY WITH A WEAK COLD
FRONT PUSHING ACROSS THE REGION LATE FRIDAY MORNING. THE FRONT
FALLS APART AS IT CROSSES THE NORTHERN SIERRA WITH THE WAVE
WEAKENING CONSIDERABLY EAST OF THE CREST. THEREFORE, DO NOT EXPECT
SIGNIFICANT RAIN/SNOW TO OCCUR. BEST CHANCES FOR PRECIPITATION
WILL BE ALONG THE SIERRA FROM TAHOE NORTH INTO NORTHEAST CA
EXTENDING INTO NORTHERN WASHOE COUNTY. INSTABILITY ACROSS NORTHERN
NV MAY LEAD TO PRECIPITATION DEVELOPING IN THE CENTRAL BASIN AND
RANGE AS WELL. MOST FORECAST GUIDANCE LARGELY SHADOWS OUT THE
SIERRA FRONT, BUT WITH WESTERLY FLOW THINK THAT A FEW SPOTS MAY
END UP SEEING SHOWERS SO HAVE KEPT IN LOW END CHANCES. THE SYSTEM
QUICKLY EXITS EASTWARD, BUT UPSLOPE FLOW MAY KEEP SHOWERS
LINGERING IN THE SIERRA. SNOW LEVELS WILL MAINLY BE 4500-5500 FEET
NORTH OF HIGHWAY 50 WITH 5500-6500 FEET SOUTH OF THERE WITH SLICK
ROADS AND TRAVEL IMPACTS POSSIBLE.

A DIRTY RIDGE BEGINS TO BUILD INTO THE WEST SATURDAY INTO SUNDAY
WITH WARM AIR ADVECTION PRECIPITATION DEVELOPING ACROSS NORTHERN
CA/NV. THE JET IS DRIVEN INTO THE PACIFIC NORTHWEST OVER THE TOP
OF THE RIDGE, BUT THERE IS SOME DISAGREEMENT JUST HOW FAR NORTH THE
JET CORE WILL BE. THIS WILL IMPACT HOW FAR SOUTH WE MAY SEE
RAIN/SNOW DEVELOP LATE SATURDAY INTO SUNDAY. THE NORTHERN END OF
THE RANGE IS NORTH OF A PORTOLA-LOVELOCK LINE WITH THE SOUTHERN
END OF THE SPECTRUM BEING DOWN TO MAMMOTH AND THE WHITE MOUNTAINS.
FOR NOW HAVE MAINTAINED SLIGHT CHANCE POPS AREA WIDE WITH CHANCE
POPS ACROSS FAR NORTHERN CA/NV TO ACCOUNT FOR THE UNCERTAINTY.
SNOW LEVELS WILL BE RISING IN THIS PATTERN TO 6000-7000 FEET. DJ

LONG TERM...SUNDAY THROUGH WEDNESDAY/CHRISTMAS EVE...
SUNDAY THROUGH TUESDAY, EASTERN CALIFORNIA AND WESTERN NEVADA WILL
REMAIN UNDER AN UPPER RIDGE WHICH WILL STEER ANY DISTURBANCES INTO
THE PACIFIC NORTHWEST AND NORTHERN ROCKIES. THE RIDGE WILL BE RATHER
"DIRTY" WITH LOTS OF MID AND/OR HIGH CLOUDS, ESPECIALLY NORTH OF
INTERSTATE 80. TEMPERATURES SHOULD REMAIN MILD AT 5-10 DEGREES ABOVE
AVERAGE.

NEXT WEDNESDAY AND WEDNESDAY NIGHT (CHRISTMAS EVE), MODELS ARE
STARTING TO SHOW AN INTERESTING POSSIBILITY AS THE LARGE UPPER RIDGE
NEAR THE PACIFIC COAST BEGINS TO REBUILD/RETROGRADE INTO THE EASTERN
PACIFIC AND GULF OF ALASKA. THIS RETROGRESSION IS EXPECTED TO ALLOW
A SLIDER-TYPE SYSTEM TO DIVE DOWN INTO THE WESTERN CONUS BY LATE ON
CHRISTMAS EVE OR ON CHRISTMAS DAY/NEXT THURSDAY. ENSEMBLE SPREADS
ARE LARGE AT THIS TIME INDICATING VAST UNCERTAINTY, ALTHOUGH THE
UNCERTAINTY APPEARS TO BE RELATED TO THE STRENGTH AND HOW FAR SOUTH
THE SLIDER DIGS VERSUS WHETHER IT ACTUALLY EXISTS. THEREFORE, I
WOULD EXPECT SOME KIND OF SLIDER SYSTEM WITH INCREASING WINDS FOR
WEDNESDAY FOLLOWED BY COLDER TEMPERATURES FOR CHRISTMAS DAY. AS FAR
AS PRECIPITATION AND HOW COLD IT GETS, THAT REMAINS VERY UNCERTAIN
AT THIS TIME. STAY TUNED! SNYDER

AVIATION...
PLENTY OF MOISTURE AND A SLIGHTLY UNSTABLE ATMOSPHERE IS PRODUCING
WIDESPREAD CUMULUS ALONG WITH ISOLATED SHOWERS IN THE SIERRA AND OUT
INTO FAR WESTERN NEVADA THIS AFTERNOON. CLOUD DECKS ARE GENERALLY
VFR, ALTHOUGH AREAS OF TERRAIN OBSCUREMENT CAN BE FOUND IN EASTERN
CALIFORNIA/THE SIERRA AND IN SHOWERS ELSEWHERE.

TONIGHT (GENERALLY AFTER 03Z-06Z), YET ANOTHER WEAK UPPER
DISTURBANCE WILL MOVE OVER NORTHEAST CALIFORNIA AND WESTERN NEVADA.
THIS WILL BRING A ROUND OF SCATTERED (WESTERN NEVADA) TO NUMEROUS
(SIERRA) LIGHT SNOW SHOWERS TO THE REGION. THIS WILL BRING DOWN
CIGS/VIS TO IFR IN THE SIERRA WITH AREAS OF MVFR CIGS OUT INTO
WESTERN NEVADA. -SHSN SHOULD DISSIPATE QUICKLY BY AROUND 12Z/4AM
THURSDAY AS THE DISTURBANCE EXITS THE REGION.

AS FAR AS SNOWFALL ACCUMULATIONS ON UNTREATED PAVEMENTS/TARMACS,
SHOWERS SHOULD REMAIN LIGHT AND SPORADIC ENOUGH THAT WESTERN NEVADA
TERMINALS BELOW 5000 FEET REMAIN MAINLY WET, WITH A DUSTING POSSIBLE
ABOVE 5000 FEET (KRTS). IN THE NORTHERN SIERRA AND FOR NORTHEAST
CALIFORNIA (KSVE), SNOW COULD BE A BIT HEAVIER SO A LIGHT
ACCUMULATION (UP TO AN INCH) IS POSSIBLE ON UNTREATED PAVEMENT.

THURSDAY AND THURSDAY NIGHT, A RIDGE BUILDS OVERHEAD FOR DRIER
CONDITIONS BEFORE A COLD FRONT MOVES INTO EXTREME NORTHERN NEVADA
AND CALIFORNIA FRIDAY FOR ANOTHER SHOT AT MOUNTAIN SNOW AND VALLEY
RAIN. SNYDER

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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









000
FXUS65 KREV 180620
AFDREV

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RENO NV
1020 PM PST WED DEC 17 2014

.UPDATE...
ALREADY WEAK UPPER FORCING WAS WANING AND PUSHING THROUGH WESTERN
NV THIS EVENING AS BAND OF RAIN AND SNOW LAGGED BEHIND OVER CA.
MOST MODELS HAVE BACKED WAY OFF ON RAIN AND SNOW FOR AREAS EAST OF
THE SIERRA AS A RESULT OF THE LATEST TRENDS. THE BAND OF RAIN AND
SNOW, IF IT CAN HOLD TOGETHER, MAY REACH THE CREST WITH SOME LIGHT
SNOW POSSIBLE IN THE TAHOE BASIN AND ALONG HIGHWAY 89 NORTH OF
TRUCKEE, BUT SNOWFALL AMOUNTS ARE GOING TO BE LIGHT. WE UPDATED TO
SIGNIFICANTLY LOWER POPS ACROSS WESTERN NV AND EVEN PARTS OF THE
EASTERN SIERRA. SNOWFALL AMOUNTS UP TO 2 INCHES ARE POSSIBLE WEST
OF HIGHWAY 89 WITH AN INCH OR LESS AT KTVL/KTRK OVERNIGHT. WHILE
AMOUNTS WILL BE LIGHT, TRAVEL MAY BECOME SLICK OVERNIGHT INTO
THURSDAY MORNING FOR AREA PASSES, ESPECIALLY DONNER AND ECHO
SUMMITS, AND ALONG HIGHWAY 89. A FEW FLURRIES MAY VISIT THE
HIGHWAY 395 CORRIDOR. HOHMANN

&&

.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE REGION THURSDAY BEFORE ANOTHER
WEAK STORM SYSTEM BRINGS ANOTHER CHANCE OF RAIN AND SNOW FRIDAY
THROUGH SATURDAY. HIGH PRESSURE WILL THEN BUILD SUNDAY THROUGH THE
FIRST PART OF NEXT WEEK.

&&

.PREVIOUS DISCUSSION... /ISSUED 722 PM PST WED DEC 17 2014/

SYNOPSIS...

A WEAK AREA OF LOW PRESSURE MOVES ACROSS NORTHERN CALIFORNIA AND
WESTERN NEVADA TONIGHT AND EARLY THURSDAY. THIS LOW PRESSURE
SHOULD BRING ANOTHER ROUND OF LIGHT SNOW TO AREAS NORTH OF HIGHWAY
50 AND ALONG THE SIERRA CREST IN MONO COUNTY. ANOTHER SYSTEM WILL
IMPACT THE SAME AREAS FRIDAY WITH ANOTHER ROUND OF LIGHT SNOW. SLICK
AND SNOW COVERED ROADS ARE LIKELY FOR THE SIERRA PASSES THROUGH
FRIDAY. A FEW SLICK SPOTS ARE POSSIBLE IN THE LOWER VALLEYS AS WELL
THAT COULD IMPACT THE MORNING COMMUTE THURSDAY.

SHORT TERM...
NEXT WAVE IS MOVING TOWARD THE COAST NOW AND SHOULD IMPACT OUR
FORECAST AREA TONIGHT. THIS DOES NOT APPEAR TO BE AN OVERLY STRONG
WAVE...BUT THERE IS ENOUGH MOISTURE WITH IT TO PRODUCE LIGHT PCPN.
FORECAST MODELS DO NOT SHOW AN OVERWHELMING AMOUNT OF FORCING WITH
THIS SYSTEM. THERE IS A WARM AIR ADVECTION SIGNATURE WITH THE SYSTEM
THAT...COUPLED WITH FAIRLY DEEP MOISTURE...SHOULD PUSH PCPN OVER THE
SIERRA INTO WESTERN NEVADA OVERNIGHT.

THE BEST CHANCE FOR PCPN IN THE EVENING SHOULD BE IN NORTHEAST CA
FROM ABOUT THE TAHOE BASIN NORTHWARD. THEN THE PCPN CHANCES SPREAD
EAST AND SOUTH THROUGH THE OVERNIGHT HOURS. WITH WARM AIR ADVECTION
SYSTEMS LIKE THIS THE AMOUNT OF PCPN DOES NOT TEND TO BE VERY HIGH
OR DRIVEN MUCH BY TERRAIN INFLUENCES. THUS...IT IS NOT OUT OF THE
QUESTION FOR AREAS EAST OF THE SIERRA TO GET ABOUT AS MUCH AS
POINTS IN THE SIERRA AND FAR NORTHEAST CA. SNOW LEVELS COULD BE
DOWN TO EVEN THE LOWEST VALLEY FLOORS IN THIS WARM AIR ADVECTION
AS WELL. FORECAST SOUNDINGS EAST OF THE SIERRA SHOW A DROP TO NEAR
4500 FEET FOR THE SNOW LEVELS LATE TONIGHT.

SO...WHAT DOES THIS MEAN FOR OVERNIGHT? HIGH POPS AND LOW QPF WITH
MAYBE UP TO AN INCH OF SNOW FOR AREAS OF WESTERN NEVADA. IN THE
TAHOE BASIN...NORTHEAST CA AND THE HIGHER ELEVATIONS OF MONO
COUNTY...SNOW AMOUNTS SHOULD BE AN INCH OR TWO EXCEPT IN THE
HIGHEST ELEVATIONS WHERE UP TO 4 INCHES IS POSSIBLE. SO...WE WILL
NOT PLAN ANY ADVISORIES AT THIS TIME...BUT BE ADVISED THAT EVEN AN
INCH OF SNOW COULD RESULT IN SLICK ROADS FOR THE MORNING COMMUTE.
BE PREPARED FOR A FEW TRAVEL DELAYS FOR THE THURSDAY MORNING
COMMUTE FOR EASTERN CA AND FAR WESTERN NV.

THIS WAVE MOVES EAST THURSDAY AFTERNOON WITH A FEW LINGERING
SHOWERS DURING THE DAY. A BRIEF PERIOD OF RIDGING DEVELOPS LATE
THURSDAY EVENING...BUT THIS IS QUICKLY REPLACED BY ANOTHER WAVE
MOVING ACROSS THE NORTHERN FORECAST AREA FRIDAY. 20

FRIDAY AND SATURDAY...
ANOTHER WAVE MOVES ACROSS NORTHERN CA/NV FRIDAY WITH A WEAK COLD
FRONT PUSHING ACROSS THE REGION LATE FRIDAY MORNING. THE FRONT
FALLS APART AS IT CROSSES THE NORTHERN SIERRA WITH THE WAVE
WEAKENING CONSIDERABLY EAST OF THE CREST. THEREFORE, DO NOT EXPECT
SIGNIFICANT RAIN/SNOW TO OCCUR. BEST CHANCES FOR PRECIPITATION
WILL BE ALONG THE SIERRA FROM TAHOE NORTH INTO NORTHEAST CA
EXTENDING INTO NORTHERN WASHOE COUNTY. INSTABILITY ACROSS NORTHERN
NV MAY LEAD TO PRECIPITATION DEVELOPING IN THE CENTRAL BASIN AND
RANGE AS WELL. MOST FORECAST GUIDANCE LARGELY SHADOWS OUT THE
SIERRA FRONT, BUT WITH WESTERLY FLOW THINK THAT A FEW SPOTS MAY
END UP SEEING SHOWERS SO HAVE KEPT IN LOW END CHANCES. THE SYSTEM
QUICKLY EXITS EASTWARD, BUT UPSLOPE FLOW MAY KEEP SHOWERS
LINGERING IN THE SIERRA. SNOW LEVELS WILL MAINLY BE 4500-5500 FEET
NORTH OF HIGHWAY 50 WITH 5500-6500 FEET SOUTH OF THERE WITH SLICK
ROADS AND TRAVEL IMPACTS POSSIBLE.

A DIRTY RIDGE BEGINS TO BUILD INTO THE WEST SATURDAY INTO SUNDAY
WITH WARM AIR ADVECTION PRECIPITATION DEVELOPING ACROSS NORTHERN
CA/NV. THE JET IS DRIVEN INTO THE PACIFIC NORTHWEST OVER THE TOP
OF THE RIDGE, BUT THERE IS SOME DISAGREEMENT JUST HOW FAR NORTH THE
JET CORE WILL BE. THIS WILL IMPACT HOW FAR SOUTH WE MAY SEE
RAIN/SNOW DEVELOP LATE SATURDAY INTO SUNDAY. THE NORTHERN END OF
THE RANGE IS NORTH OF A PORTOLA-LOVELOCK LINE WITH THE SOUTHERN
END OF THE SPECTRUM BEING DOWN TO MAMMOTH AND THE WHITE MOUNTAINS.
FOR NOW HAVE MAINTAINED SLIGHT CHANCE POPS AREA WIDE WITH CHANCE
POPS ACROSS FAR NORTHERN CA/NV TO ACCOUNT FOR THE UNCERTAINTY.
SNOW LEVELS WILL BE RISING IN THIS PATTERN TO 6000-7000 FEET. DJ

LONG TERM...SUNDAY THROUGH WEDNESDAY/CHRISTMAS EVE...
SUNDAY THROUGH TUESDAY, EASTERN CALIFORNIA AND WESTERN NEVADA WILL
REMAIN UNDER AN UPPER RIDGE WHICH WILL STEER ANY DISTURBANCES INTO
THE PACIFIC NORTHWEST AND NORTHERN ROCKIES. THE RIDGE WILL BE RATHER
"DIRTY" WITH LOTS OF MID AND/OR HIGH CLOUDS, ESPECIALLY NORTH OF
INTERSTATE 80. TEMPERATURES SHOULD REMAIN MILD AT 5-10 DEGREES ABOVE
AVERAGE.

NEXT WEDNESDAY AND WEDNESDAY NIGHT (CHRISTMAS EVE), MODELS ARE
STARTING TO SHOW AN INTERESTING POSSIBILITY AS THE LARGE UPPER RIDGE
NEAR THE PACIFIC COAST BEGINS TO REBUILD/RETROGRADE INTO THE EASTERN
PACIFIC AND GULF OF ALASKA. THIS RETROGRESSION IS EXPECTED TO ALLOW
A SLIDER-TYPE SYSTEM TO DIVE DOWN INTO THE WESTERN CONUS BY LATE ON
CHRISTMAS EVE OR ON CHRISTMAS DAY/NEXT THURSDAY. ENSEMBLE SPREADS
ARE LARGE AT THIS TIME INDICATING VAST UNCERTAINTY, ALTHOUGH THE
UNCERTAINTY APPEARS TO BE RELATED TO THE STRENGTH AND HOW FAR SOUTH
THE SLIDER DIGS VERSUS WHETHER IT ACTUALLY EXISTS. THEREFORE, I
WOULD EXPECT SOME KIND OF SLIDER SYSTEM WITH INCREASING WINDS FOR
WEDNESDAY FOLLOWED BY COLDER TEMPERATURES FOR CHRISTMAS DAY. AS FAR
AS PRECIPITATION AND HOW COLD IT GETS, THAT REMAINS VERY UNCERTAIN
AT THIS TIME. STAY TUNED! SNYDER

AVIATION...
PLENTY OF MOISTURE AND A SLIGHTLY UNSTABLE ATMOSPHERE IS PRODUCING
WIDESPREAD CUMULUS ALONG WITH ISOLATED SHOWERS IN THE SIERRA AND OUT
INTO FAR WESTERN NEVADA THIS AFTERNOON. CLOUD DECKS ARE GENERALLY
VFR, ALTHOUGH AREAS OF TERRAIN OBSCUREMENT CAN BE FOUND IN EASTERN
CALIFORNIA/THE SIERRA AND IN SHOWERS ELSEWHERE.

TONIGHT (GENERALLY AFTER 03Z-06Z), YET ANOTHER WEAK UPPER
DISTURBANCE WILL MOVE OVER NORTHEAST CALIFORNIA AND WESTERN NEVADA.
THIS WILL BRING A ROUND OF SCATTERED (WESTERN NEVADA) TO NUMEROUS
(SIERRA) LIGHT SNOW SHOWERS TO THE REGION. THIS WILL BRING DOWN
CIGS/VIS TO IFR IN THE SIERRA WITH AREAS OF MVFR CIGS OUT INTO
WESTERN NEVADA. -SHSN SHOULD DISSIPATE QUICKLY BY AROUND 12Z/4AM
THURSDAY AS THE DISTURBANCE EXITS THE REGION.

AS FAR AS SNOWFALL ACCUMULATIONS ON UNTREATED PAVEMENTS/TARMACS,
SHOWERS SHOULD REMAIN LIGHT AND SPORADIC ENOUGH THAT WESTERN NEVADA
TERMINALS BELOW 5000 FEET REMAIN MAINLY WET, WITH A DUSTING POSSIBLE
ABOVE 5000 FEET (KRTS). IN THE NORTHERN SIERRA AND FOR NORTHEAST
CALIFORNIA (KSVE), SNOW COULD BE A BIT HEAVIER SO A LIGHT
ACCUMULATION (UP TO AN INCH) IS POSSIBLE ON UNTREATED PAVEMENT.

THURSDAY AND THURSDAY NIGHT, A RIDGE BUILDS OVERHEAD FOR DRIER
CONDITIONS BEFORE A COLD FRONT MOVES INTO EXTREME NORTHERN NEVADA
AND CALIFORNIA FRIDAY FOR ANOTHER SHOT AT MOUNTAIN SNOW AND VALLEY
RAIN. SNYDER

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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










000
FXUS65 KREV 180322 CCA
AFDREV

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE RENO NV
722 PM PST WED DEC 17 2014

.SYNOPSIS...

A WEAK AREA OF LOW PRESSURE MOVES ACROSS NORTHERN CALIFORNIA AND
WESTERN NEVADA TONIGHT AND EARLY THURSDAY. THIS LOW PRESSURE
SHOULD BRING ANOTHER ROUND OF LIGHT SNOW TO AREAS NORTH OF HIGHWAY
50 AND ALONG THE SIERRA CREST IN MONO COUNTY. ANOTHER SYSTEM WILL
IMPACT THE SAME AREAS FRIDAY WITH ANOTHER ROUND OF LIGHT SNOW. SLICK
AND SNOW COVERED ROADS ARE LIKELY FOR THE SIERRA PASSES THROUGH
FRIDAY. A FEW SLICK SPOTS ARE POSSIBLE IN THE LOWER VALLEYS AS WELL
THAT COULD IMPACT THE MORNING COMMUTE THURSDAY.

&&

.SHORT TERM...
NEXT WAVE IS MOVING TOWARD THE COAST NOW AND SHOULD IMPACT OUR
FORECAST AREA TONIGHT. THIS DOES NOT APPEAR TO BE AN OVERLY STRONG
WAVE...BUT THERE IS ENOUGH MOISTURE WITH IT TO PRODUCE LIGHT PCPN.
FORECAST MODELS DO NOT SHOW AN OVERWHELMING AMOUNT OF FORCING WITH
THIS SYSTEM. THERE IS A WARM AIR ADVECTION SIGNATURE WITH THE SYSTEM
THAT...COUPLED WITH FAIRLY DEEP MOISTURE...SHOULD PUSH PCPN OVER THE
SIERRA INTO WESTERN NEVADA OVERNIGHT.

THE BEST CHANCE FOR PCPN IN THE EVENING SHOULD BE IN NORTHEAST CA
FROM ABOUT THE TAHOE BASIN NORTHWARD. THEN THE PCPN CHANCES SPREAD
EAST AND SOUTH THROUGH THE OVERNIGHT HOURS. WITH WARM AIR ADVECTION
SYSTEMS LIKE THIS THE AMOUNT OF PCPN DOES NOT TEND TO BE VERY HIGH
OR DRIVEN MUCH BY TERRAIN INFLUENCES. THUS...IT IS NOT OUT OF THE
QUESTION FOR AREAS EAST OF THE SIERRA TO GET ABOUT AS MUCH AS
POINTS IN THE SIERRA AND FAR NORTHEAST CA. SNOW LEVELS COULD BE
DOWN TO EVEN THE LOWEST VALLEY FLOORS IN THIS WARM AIR ADVECTION
AS WELL. FORECAST SOUNDINGS EAST OF THE SIERRA SHOW A DROP TO NEAR
4500 FEET FOR THE SNOW LEVELS LATE TONIGHT.

SO...WHAT DOES THIS MEAN FOR OVERNIGHT? HIGH POPS AND LOW QPF WITH
MAYBE UP TO AN INCH OF SNOW FOR AREAS OF WESTERN NEVADA. IN THE
TAHOE BASIN...NORTHEAST CA AND THE HIGHER ELEVATIONS OF MONO
COUNTY...SNOW AMOUNTS SHOULD BE AN INCH OR TWO EXCEPT IN THE
HIGHEST ELEVATIONS WHERE UP TO 4 INCHES IS POSSIBLE. SO...WE WILL
NOT PLAN ANY ADVISORIES AT THIS TIME...BUT BE ADVISED THAT EVEN AN
INCH OF SNOW COULD RESULT IN SLICK ROADS FOR THE MORNING COMMUTE.
BE PREPARED FOR A FEW TRAVEL DELAYS FOR THE THURSDAY MORNING
COMMUTE FOR EASTERN CA AND FAR WESTERN NV.

THIS WAVE MOVES EAST THURSDAY AFTERNOON WITH A FEW LINGERING
SHOWERS DURING THE DAY. A BRIEF PERIOD OF RIDGING DEVELOPS LATE
THURSDAY EVENING...BUT THIS IS QUICKLY REPLACED BY ANOTHER WAVE
MOVING ACROSS THE NORTHERN FORECAST AREA FRIDAY. 20

FRIDAY AND SATURDAY...
ANOTHER WAVE MOVES ACROSS NORTHERN CA/NV FRIDAY WITH A WEAK COLD
FRONT PUSHING ACROSS THE REGION LATE FRIDAY MORNING. THE FRONT
FALLS APART AS IT CROSSES THE NORTHERN SIERRA WITH THE WAVE
WEAKENING CONSIDERABLY EAST OF THE CREST. THEREFORE, DO NOT EXPECT
SIGNIFICANT RAIN/SNOW TO OCCUR. BEST CHANCES FOR PRECIPITATION
WILL BE ALONG THE SIERRA FROM TAHOE NORTH INTO NORTHEAST CA
EXTENDING INTO NORTHERN WASHOE COUNTY. INSTABILITY ACROSS NORTHERN
NV MAY LEAD TO PRECIPITATION DEVELOPING IN THE CENTRAL BASIN AND
RANGE AS WELL. MOST FORECAST GUIDANCE LARGELY SHADOWS OUT THE
SIERRA FRONT, BUT WITH WESTERLY FLOW THINK THAT A FEW SPOTS MAY
END UP SEEING SHOWERS SO HAVE KEPT IN LOW END CHANCES. THE SYSTEM
QUICKLY EXITS EASTWARD, BUT UPSLOPE FLOW MAY KEEP SHOWERS
LINGERING IN THE SIERRA. SNOW LEVELS WILL MAINLY BE 4500-5500 FEET
NORTH OF HIGHWAY 50 WITH 5500-6500 FEET SOUTH OF THERE WITH SLICK
ROADS AND TRAVEL IMPACTS POSSIBLE.

A DIRTY RIDGE BEGINS TO BUILD INTO THE WEST SATURDAY INTO SUNDAY
WITH WARM AIR ADVECTION PRECIPITATION DEVELOPING ACROSS NORTHERN
CA/NV. THE JET IS DRIVEN INTO THE PACIFIC NORTHWEST OVER THE TOP
OF THE RIDGE, BUT THERE IS SOME DISAGREEMENT JUST HOW FAR NORTH THE
JET CORE WILL BE. THIS WILL IMPACT HOW FAR SOUTH WE MAY SEE
RAIN/SNOW DEVELOP LATE SATURDAY INTO SUNDAY. THE NORTHERN END OF
THE RANGE IS NORTH OF A PORTOLA-LOVELOCK LINE WITH THE SOUTHERN
END OF THE SPECTRUM BEING DOWN TO MAMMOTH AND THE WHITE MOUNTAINS.
FOR NOW HAVE MAINTAINED SLIGHT CHANCE POPS AREA WIDE WITH CHANCE
POPS ACROSS FAR NORTHERN CA/NV TO ACCOUNT FOR THE UNCERTAINTY.
SNOW LEVELS WILL BE RISING IN THIS PATTERN TO 6000-7000 FEET. DJ

.LONG TERM...SUNDAY THROUGH WEDNESDAY/CHRISTMAS EVE...
SUNDAY THROUGH TUESDAY, EASTERN CALIFORNIA AND WESTERN NEVADA WILL
REMAIN UNDER AN UPPER RIDGE WHICH WILL STEER ANY DISTURBANCES INTO
THE PACIFIC NORTHWEST AND NORTHERN ROCKIES. THE RIDGE WILL BE RATHER
"DIRTY" WITH LOTS OF MID AND/OR HIGH CLOUDS, ESPECIALLY NORTH OF
INTERSTATE 80. TEMPERATURES SHOULD REMAIN MILD AT 5-10 DEGREES ABOVE
AVERAGE.

NEXT WEDNESDAY AND WEDNESDAY NIGHT (CHRISTMAS EVE), MODELS ARE
STARTING TO SHOW AN INTERESTING POSSIBILITY AS THE LARGE UPPER RIDGE
NEAR THE PACIFIC COAST BEGINS TO REBUILD/RETROGRADE INTO THE EASTERN
PACIFIC AND GULF OF ALASKA. THIS RETROGRESSION IS EXPECTED TO ALLOW
A SLIDER-TYPE SYSTEM TO DIVE DOWN INTO THE WESTERN CONUS BY LATE ON
CHRISTMAS EVE OR ON CHRISTMAS DAY/NEXT THURSDAY. ENSEMBLE SPREADS
ARE LARGE AT THIS TIME INDICATING VAST UNCERTAINTY, ALTHOUGH THE
UNCERTAINTY APPEARS TO BE RELATED TO THE STRENGTH AND HOW FAR SOUTH
THE SLIDER DIGS VERSUS WHETHER IT ACTUALLY EXISTS. THEREFORE, I
WOULD EXPECT SOME KIND OF SLIDER SYSTEM WITH INCREASING WINDS FOR
WEDNESDAY FOLLOWED BY COLDER TEMPERATURES FOR CHRISTMAS DAY. AS FAR
AS PRECIPITATION AND HOW COLD IT GETS, THAT REMAINS VERY UNCERTAIN
AT THIS TIME. STAY TUNED! SNYDER

&&

.AVIATION...
PLENTY OF MOISTURE AND A SLIGHTLY UNSTABLE ATMOSPHERE IS PRODUCING
WIDESPREAD CUMULUS ALONG WITH ISOLATED SHOWERS IN THE SIERRA AND OUT
INTO FAR WESTERN NEVADA THIS AFTERNOON. CLOUD DECKS ARE GENERALLY
VFR, ALTHOUGH AREAS OF TERRAIN OBSCUREMENT CAN BE FOUND IN EASTERN
CALIFORNIA/THE SIERRA AND IN SHOWERS ELSEWHERE.

TONIGHT (GENERALLY AFTER 03Z-06Z), YET ANOTHER WEAK UPPER
DISTURBANCE WILL MOVE OVER NORTHEAST CALIFORNIA AND WESTERN NEVADA.
THIS WILL BRING A ROUND OF SCATTERED (WESTERN NEVADA) TO NUMEROUS
(SIERRA) LIGHT SNOW SHOWERS TO THE REGION. THIS WILL BRING DOWN
CIGS/VIS TO IFR IN THE SIERRA WITH AREAS OF MVFR CIGS OUT INTO
WESTERN NEVADA. -SHSN SHOULD DISSIPATE QUICKLY BY AROUND 12Z/4AM
THURSDAY AS THE DISTURBANCE EXITS THE REGION.

AS FAR AS SNOWFALL ACCUMULATIONS ON UNTREATED PAVEMENTS/TARMACS,
SHOWERS SHOULD REMAIN LIGHT AND SPORADIC ENOUGH THAT WESTERN NEVADA
TERMINALS BELOW 5000 FEET REMAIN MAINLY WET, WITH A DUSTING POSSIBLE
ABOVE 5000 FEET (KRTS). IN THE NORTHERN SIERRA AND FOR NORTHEAST
CALIFORNIA (KSVE), SNOW COULD BE A BIT HEAVIER SO A LIGHT
ACCUMULATION (UP TO AN INCH) IS POSSIBLE ON UNTREATED PAVEMENT.

THURSDAY AND THURSDAY NIGHT, A RIDGE BUILDS OVERHEAD FOR DRIER
CONDITIONS BEFORE A COLD FRONT MOVES INTO EXTREME NORTHERN NEVADA
AND CALIFORNIA FRIDAY FOR ANOTHER SHOT AT MOUNTAIN SNOW AND VALLEY
RAIN. SNYDER

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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











000
FXUS65 KREV 180322 CCA
AFDREV

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE RENO NV
722 PM PST WED DEC 17 2014

.SYNOPSIS...

A WEAK AREA OF LOW PRESSURE MOVES ACROSS NORTHERN CALIFORNIA AND
WESTERN NEVADA TONIGHT AND EARLY THURSDAY. THIS LOW PRESSURE
SHOULD BRING ANOTHER ROUND OF LIGHT SNOW TO AREAS NORTH OF HIGHWAY
50 AND ALONG THE SIERRA CREST IN MONO COUNTY. ANOTHER SYSTEM WILL
IMPACT THE SAME AREAS FRIDAY WITH ANOTHER ROUND OF LIGHT SNOW. SLICK
AND SNOW COVERED ROADS ARE LIKELY FOR THE SIERRA PASSES THROUGH
FRIDAY. A FEW SLICK SPOTS ARE POSSIBLE IN THE LOWER VALLEYS AS WELL
THAT COULD IMPACT THE MORNING COMMUTE THURSDAY.

&&

.SHORT TERM...
NEXT WAVE IS MOVING TOWARD THE COAST NOW AND SHOULD IMPACT OUR
FORECAST AREA TONIGHT. THIS DOES NOT APPEAR TO BE AN OVERLY STRONG
WAVE...BUT THERE IS ENOUGH MOISTURE WITH IT TO PRODUCE LIGHT PCPN.
FORECAST MODELS DO NOT SHOW AN OVERWHELMING AMOUNT OF FORCING WITH
THIS SYSTEM. THERE IS A WARM AIR ADVECTION SIGNATURE WITH THE SYSTEM
THAT...COUPLED WITH FAIRLY DEEP MOISTURE...SHOULD PUSH PCPN OVER THE
SIERRA INTO WESTERN NEVADA OVERNIGHT.

THE BEST CHANCE FOR PCPN IN THE EVENING SHOULD BE IN NORTHEAST CA
FROM ABOUT THE TAHOE BASIN NORTHWARD. THEN THE PCPN CHANCES SPREAD
EAST AND SOUTH THROUGH THE OVERNIGHT HOURS. WITH WARM AIR ADVECTION
SYSTEMS LIKE THIS THE AMOUNT OF PCPN DOES NOT TEND TO BE VERY HIGH
OR DRIVEN MUCH BY TERRAIN INFLUENCES. THUS...IT IS NOT OUT OF THE
QUESTION FOR AREAS EAST OF THE SIERRA TO GET ABOUT AS MUCH AS
POINTS IN THE SIERRA AND FAR NORTHEAST CA. SNOW LEVELS COULD BE
DOWN TO EVEN THE LOWEST VALLEY FLOORS IN THIS WARM AIR ADVECTION
AS WELL. FORECAST SOUNDINGS EAST OF THE SIERRA SHOW A DROP TO NEAR
4500 FEET FOR THE SNOW LEVELS LATE TONIGHT.

SO...WHAT DOES THIS MEAN FOR OVERNIGHT? HIGH POPS AND LOW QPF WITH
MAYBE UP TO AN INCH OF SNOW FOR AREAS OF WESTERN NEVADA. IN THE
TAHOE BASIN...NORTHEAST CA AND THE HIGHER ELEVATIONS OF MONO
COUNTY...SNOW AMOUNTS SHOULD BE AN INCH OR TWO EXCEPT IN THE
HIGHEST ELEVATIONS WHERE UP TO 4 INCHES IS POSSIBLE. SO...WE WILL
NOT PLAN ANY ADVISORIES AT THIS TIME...BUT BE ADVISED THAT EVEN AN
INCH OF SNOW COULD RESULT IN SLICK ROADS FOR THE MORNING COMMUTE.
BE PREPARED FOR A FEW TRAVEL DELAYS FOR THE THURSDAY MORNING
COMMUTE FOR EASTERN CA AND FAR WESTERN NV.

THIS WAVE MOVES EAST THURSDAY AFTERNOON WITH A FEW LINGERING
SHOWERS DURING THE DAY. A BRIEF PERIOD OF RIDGING DEVELOPS LATE
THURSDAY EVENING...BUT THIS IS QUICKLY REPLACED BY ANOTHER WAVE
MOVING ACROSS THE NORTHERN FORECAST AREA FRIDAY. 20

FRIDAY AND SATURDAY...
ANOTHER WAVE MOVES ACROSS NORTHERN CA/NV FRIDAY WITH A WEAK COLD
FRONT PUSHING ACROSS THE REGION LATE FRIDAY MORNING. THE FRONT
FALLS APART AS IT CROSSES THE NORTHERN SIERRA WITH THE WAVE
WEAKENING CONSIDERABLY EAST OF THE CREST. THEREFORE, DO NOT EXPECT
SIGNIFICANT RAIN/SNOW TO OCCUR. BEST CHANCES FOR PRECIPITATION
WILL BE ALONG THE SIERRA FROM TAHOE NORTH INTO NORTHEAST CA
EXTENDING INTO NORTHERN WASHOE COUNTY. INSTABILITY ACROSS NORTHERN
NV MAY LEAD TO PRECIPITATION DEVELOPING IN THE CENTRAL BASIN AND
RANGE AS WELL. MOST FORECAST GUIDANCE LARGELY SHADOWS OUT THE
SIERRA FRONT, BUT WITH WESTERLY FLOW THINK THAT A FEW SPOTS MAY
END UP SEEING SHOWERS SO HAVE KEPT IN LOW END CHANCES. THE SYSTEM
QUICKLY EXITS EASTWARD, BUT UPSLOPE FLOW MAY KEEP SHOWERS
LINGERING IN THE SIERRA. SNOW LEVELS WILL MAINLY BE 4500-5500 FEET
NORTH OF HIGHWAY 50 WITH 5500-6500 FEET SOUTH OF THERE WITH SLICK
ROADS AND TRAVEL IMPACTS POSSIBLE.

A DIRTY RIDGE BEGINS TO BUILD INTO THE WEST SATURDAY INTO SUNDAY
WITH WARM AIR ADVECTION PRECIPITATION DEVELOPING ACROSS NORTHERN
CA/NV. THE JET IS DRIVEN INTO THE PACIFIC NORTHWEST OVER THE TOP
OF THE RIDGE, BUT THERE IS SOME DISAGREEMENT JUST HOW FAR NORTH THE
JET CORE WILL BE. THIS WILL IMPACT HOW FAR SOUTH WE MAY SEE
RAIN/SNOW DEVELOP LATE SATURDAY INTO SUNDAY. THE NORTHERN END OF
THE RANGE IS NORTH OF A PORTOLA-LOVELOCK LINE WITH THE SOUTHERN
END OF THE SPECTRUM BEING DOWN TO MAMMOTH AND THE WHITE MOUNTAINS.
FOR NOW HAVE MAINTAINED SLIGHT CHANCE POPS AREA WIDE WITH CHANCE
POPS ACROSS FAR NORTHERN CA/NV TO ACCOUNT FOR THE UNCERTAINTY.
SNOW LEVELS WILL BE RISING IN THIS PATTERN TO 6000-7000 FEET. DJ

.LONG TERM...SUNDAY THROUGH WEDNESDAY/CHRISTMAS EVE...
SUNDAY THROUGH TUESDAY, EASTERN CALIFORNIA AND WESTERN NEVADA WILL
REMAIN UNDER AN UPPER RIDGE WHICH WILL STEER ANY DISTURBANCES INTO
THE PACIFIC NORTHWEST AND NORTHERN ROCKIES. THE RIDGE WILL BE RATHER
"DIRTY" WITH LOTS OF MID AND/OR HIGH CLOUDS, ESPECIALLY NORTH OF
INTERSTATE 80. TEMPERATURES SHOULD REMAIN MILD AT 5-10 DEGREES ABOVE
AVERAGE.

NEXT WEDNESDAY AND WEDNESDAY NIGHT (CHRISTMAS EVE), MODELS ARE
STARTING TO SHOW AN INTERESTING POSSIBILITY AS THE LARGE UPPER RIDGE
NEAR THE PACIFIC COAST BEGINS TO REBUILD/RETROGRADE INTO THE EASTERN
PACIFIC AND GULF OF ALASKA. THIS RETROGRESSION IS EXPECTED TO ALLOW
A SLIDER-TYPE SYSTEM TO DIVE DOWN INTO THE WESTERN CONUS BY LATE ON
CHRISTMAS EVE OR ON CHRISTMAS DAY/NEXT THURSDAY. ENSEMBLE SPREADS
ARE LARGE AT THIS TIME INDICATING VAST UNCERTAINTY, ALTHOUGH THE
UNCERTAINTY APPEARS TO BE RELATED TO THE STRENGTH AND HOW FAR SOUTH
THE SLIDER DIGS VERSUS WHETHER IT ACTUALLY EXISTS. THEREFORE, I
WOULD EXPECT SOME KIND OF SLIDER SYSTEM WITH INCREASING WINDS FOR
WEDNESDAY FOLLOWED BY COLDER TEMPERATURES FOR CHRISTMAS DAY. AS FAR
AS PRECIPITATION AND HOW COLD IT GETS, THAT REMAINS VERY UNCERTAIN
AT THIS TIME. STAY TUNED! SNYDER

&&

.AVIATION...
PLENTY OF MOISTURE AND A SLIGHTLY UNSTABLE ATMOSPHERE IS PRODUCING
WIDESPREAD CUMULUS ALONG WITH ISOLATED SHOWERS IN THE SIERRA AND OUT
INTO FAR WESTERN NEVADA THIS AFTERNOON. CLOUD DECKS ARE GENERALLY
VFR, ALTHOUGH AREAS OF TERRAIN OBSCUREMENT CAN BE FOUND IN EASTERN
CALIFORNIA/THE SIERRA AND IN SHOWERS ELSEWHERE.

TONIGHT (GENERALLY AFTER 03Z-06Z), YET ANOTHER WEAK UPPER
DISTURBANCE WILL MOVE OVER NORTHEAST CALIFORNIA AND WESTERN NEVADA.
THIS WILL BRING A ROUND OF SCATTERED (WESTERN NEVADA) TO NUMEROUS
(SIERRA) LIGHT SNOW SHOWERS TO THE REGION. THIS WILL BRING DOWN
CIGS/VIS TO IFR IN THE SIERRA WITH AREAS OF MVFR CIGS OUT INTO
WESTERN NEVADA. -SHSN SHOULD DISSIPATE QUICKLY BY AROUND 12Z/4AM
THURSDAY AS THE DISTURBANCE EXITS THE REGION.

AS FAR AS SNOWFALL ACCUMULATIONS ON UNTREATED PAVEMENTS/TARMACS,
SHOWERS SHOULD REMAIN LIGHT AND SPORADIC ENOUGH THAT WESTERN NEVADA
TERMINALS BELOW 5000 FEET REMAIN MAINLY WET, WITH A DUSTING POSSIBLE
ABOVE 5000 FEET (KRTS). IN THE NORTHERN SIERRA AND FOR NORTHEAST
CALIFORNIA (KSVE), SNOW COULD BE A BIT HEAVIER SO A LIGHT
ACCUMULATION (UP TO AN INCH) IS POSSIBLE ON UNTREATED PAVEMENT.

THURSDAY AND THURSDAY NIGHT, A RIDGE BUILDS OVERHEAD FOR DRIER
CONDITIONS BEFORE A COLD FRONT MOVES INTO EXTREME NORTHERN NEVADA
AND CALIFORNIA FRIDAY FOR ANOTHER SHOT AT MOUNTAIN SNOW AND VALLEY
RAIN. SNYDER

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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












000
FXUS65 KREV 172247
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
247 PM PST WED DEC 17 2014

.SYNOPSIS...

A WEAK AREA OF LOW PRESSURE MOVES ACROSS NORTHERN CALIFORNIA AND
WESTERN NEVADA TONIGHT AND EARLY THURSDAY. THIS LOW PRESSURE
SHOULD BRING ANOTHER ROUND OF LIGHT SNOW TO AREAS NORTH OF HIGHWAY
50 AND ALONG THE SIERRA CREST IN MONO COUNTY. ANOTHER SYSTEM WILL
IMPACT THE SAME AREAS FRIDAY WITH ANOTHER ROUND OF LIGHT SNOW. SLICK
AND SNOW COVERED ROADS ARE LIKELY FOR THE THE SIERRA PASSES
THROUGH FRIDAY. A FEW SLICK SPOTS ARE POSSIBLE THE LOWER VALLEYS
AS WELL THAT COULD IMPACT THE MORNING COMMUTE THURSDAY.

&&

.SHORT TERM...
NEXT WAVE IS MOVING TOWARD THE COAST NOW AND SHOULD IMPACT OUR
FORECAST AREA TONIGHT. THIS DOES NOT APPEAR TO BE AN OVERLY
STRONG WAVE...BUT THERE ENOUGH MOISTURE WITH IT TO PRODUCE LIGHT PCPN.
FORECAST MODELS DO NOT SHOW AN OVERWHELMING AMOUNT OF FORCING WITH
THIS SYSTEM. THERE IS A WARM AIR ADVECTION SIGNATURE WITH THE
SYSTEM THAT...COUPLED WITH FAIRLY DEEP MOISTURE...SHOULD PUSH PCPN
OVER THE SIERRA INTO WESTERN NEVADA OVERNIGHT.

THE BEST CHANCE FOR PCPN IN THE EVENING SHOULD BE IN NORTHEAST CA
FROM ABOUT THE TAHOE BASIN NORTHWARD. THEN THE PCPN CHANCES SPREAD
EAST AND SOUTH THROUGH THE OVERNIGHT HOURS. WITH WARM AIR ADVECTION
SYSTEMS LIKE THIS THE AMOUNT OF PCPN DOES NOT TEND TO BE VERY HIGH
OR DRIVEN MUCH BY TERRAIN INFLUENCES. THUS...IT IS NOT OUT OF THE
QUESTION FOR AREAS EAST OF THE SIERRA TO GET ABOUT AS MUCH AS
POINTS IN THE SIERRA AND FAR NORTHEAST CA. SNOW LEVELS COULD BE
DOWN TO EVEN THE LOWEST VALLEYS FLOORS IN THIS WARM AIR ADVECTION
AS WELL. FORECAST SOUNDINGS EAST OF THE SIERRA SHOW A DROP TO NEAR
4500 FEET FOR THE SNOW LEVELS LATE TONIGHT.

SO...WHAT DOES THIS MEAN FOR OVERNIGHT? HIGH POPS AND LOW QPF WITH
MAYBE UP TO AN INCH OF SNOW FOR AREAS OF WESTERN NEVADA. IN THE
TAHOE BASIN...NORTHEAST CA AND THE HIGHER ELEVATIONS OF MONO
COUNTY...SNOW AMOUNTS SHOULD BE AN INCH OR TWO EXCEPT IN THE
HIGHEST ELEVATIONS WHERE UP TO 4 INCHES IS POSSIBLE. SO...WE WILL
NOT PLAN ANY ADVISORIES AT THIS TIME...BUT BE ADVISED THAT EVEN AN
INCH OF SNOW COULD RESULT IN SLICK ROADS FOR THE MORNING COMMUTE.
BE PREPARED FOR A FEW TRAVEL DELAYS FOR THE THURSDAY MORNING
COMMUTE FOR EASTERN CA AND FAR WESTERN NV.

THIS WAVE MOVES EAST THURSDAY AFTERNOON WITH A FEW LINGERING
SHOWERS DURING THE DAY. A BRIEF PERIOD OF RIDGING DEVELOPS LATE
THURSDAY EVENING...BUT THIS IS QUICKLY REPLACED BY ANOTHER WAVE
MOVING ACROSS THE NORTHERN FORECAST AREA FRIDAY. 20

FRIDAY AND SATURDAY...
ANOTHER WAVE MOVES ACROSS NORTHERN CA/NV FRIDAY WITH A WEAK COLD
FRONT PUSHING ACROSS THE REGION LATE FRIDAY MORNING. THE FRONT
FALLS APART AS IT CROSSES THE NORTHERN SIERRA WITH THE WAVE
WEAKENING CONSIDERABLY EAST OF THE CREST. THEREFORE, DO NOT EXPECT
SIGNIFICANT RAIN/SNOW TO OCCUR. BEST CHANCES FOR PRECIPITATION
WILL BE ALONG THE SIERRA FROM TAHOE NORTH INTO NORTHEAST CA
EXTENDING INTO NORTHERN WASHOE COUNTY. INSTABILITY ACROSS NORTHERN
NV MAY LEAD TO PRECIPITATION DEVELOPING IN THE CENTRAL BASIN AND
RANGE AS WELL. MOST FORECAST GUIDANCE LARGELY SHADOWS OUT THE
SIERRA FRONT, BUT WITH WESTERLY FLOW THINK THAT A FEW SPOTS MAY
END UP SEEING SHOWERS SO HAVE KEPT IN LOW END CHANCES. THE SYSTEM
QUICKLY EXITS EASTWARD, BUT UPSLOPE FLOW MAY KEEP SHOWERS
LINGERING IN THE SIERRA. SNOW LEVELS WILL MAINLY BE 4500-5500 FEET
NORTH OF HIGHWAY 50 WITH 5500-6500 FEET SOUTH OF THERE WITH SLICK
ROADS AND TRAVEL IMPACTS POSSIBLE.

A DIRTY RIDGE BEGINS TO BUILD INTO THE WEST SATURDAY INTO SUNDAY
WITH WARM AIR ADVECTION PRECIPITATION DEVELOPING ACROSS NORTHERN
CA/NV. THE JET IS DRIVEN INTO THE PACIFIC NORTHWEST OVER THE TOP
OF THE RIDGE, BUT THERE IS SOME DISAGREEMENT JUST HOW FAR NORTH THE
JET CORE WILL BE. THIS WILL IMPACT HOW FAR SOUTH WE MAY SEE
RAIN/SNOW DEVELOP LATE SATURDAY INTO SUNDAY. THE NORTHERN END OF
THE RANGE IS NORTH OF A PORTOLA-LOVELOCK LINE WITH THE SOUTHERN
END OF THE SPECTRUM BEING DOWN TO MAMMOTH AND THE WHITE MOUNTAINS.
FOR NOW HAVE MAINTAINED SLIGHT CHANCE POPS AREA WIDE WITH CHANCE
POPS ACROSS FAR NORTHERN CA/NV TO ACCOUNT FOR THE UNCERTAINTY.
SNOW LEVELS WILL BE RISING IN THIS PATTERN TO 6000-7000 FEET. DJ

.LONG TERM...SUNDAY THROUGH WEDNESDAY/CHRISTMAS EVE...
SUNDAY THROUGH TUESDAY, EASTERN CALIFORNIA AND WESTERN NEVADA WILL
REMAIN UNDER AN UPPER RIDGE WHICH WILL STEER ANY DISTURBANCES INTO
THE PACIFIC NORTHWEST AND NORTHERN ROCKIES. THE RIDGE WILL BE RATHER
"DIRTY" WITH LOTS OF MID AND/OR HIGH CLOUDS, ESPECIALLY NORTH OF
INTERSTATE 80. TEMPERATURES SHOULD REMAIN MILD AT 5-10 DEGREES ABOVE
AVERAGE.

NEXT WEDNESDAY AND WEDNESDAY NIGHT (CHRISTMAS EVE), MODELS ARE
STARTING TO SHOW AN INTERESTING POSSIBILITY AS THE LARGE UPPER RIDGE
NEAR THE PACIFIC COAST BEGINS TO REBUILD/RETROGRADE INTO THE EASTERN
PACIFIC AND GULF OF ALASKA. THIS RETROGRESSION IS EXPECTED TO ALLOW
A SLIDER-TYPE SYSTEM TO DIVE DOWN INTO THE WESTERN CONUS BY LATE ON
CHRISTMAS EVE OR ON CHRISTMAS DAY/NEXT THURSDAY. ENSEMBLE SPREADS
ARE LARGE AT THIS TIME INDICATING VAST UNCERTAINTY, ALTHOUGH THE
UNCERTAINTY APPEARS TO BE RELATED TO THE STRENGTH AND HOW FAR SOUTH
THE SLIDER DIGS VERSUS WHETHER IT ACTUALLY EXISTS. THEREFORE, I
WOULD EXPECT SOME KIND OF SLIDER SYSTEM WITH INCREASING WINDS FOR
WEDNESDAY FOLLOWED BY COLDER TEMPERATURES FOR CHRISTMAS DAY. AS FAR
AS PRECIPITATION AND HOW COLD IT GETS, THAT REMAINS VERY UNCERTAIN
AT THIS TIME. STAY TUNED! SNYDER

&&

.AVIATION...
PLENTY OF MOISTURE AND A SLIGHTLY UNSTABLE ATMOSPHERE IS PRODUCING
WIDESPREAD CUMULUS ALONG WITH ISOLATED SHOWERS IN THE SIERRA AND OUT
INTO FAR WESTERN NEVADA THIS AFTERNOON. CLOUD DECKS ARE GENERALLY
VFR, ALTHOUGH AREAS OF TERRAIN OBSCUREMENT CAN BE FOUND IN EASTERN
CALIFORNIA/THE SIERRA AND IN SHOWERS ELSEWHERE.

TONIGHT (GENERALLY AFTER 03Z-06Z), YET ANOTHER WEAK UPPER
DISTURBANCE WILL MOVE OVER NORTHEAST CALIFORNIA AND WESTERN NEVADA.
THIS WILL BRING A ROUND OF SCATTERED (WESTERN NEVADA) TO NUMEROUS
(SIERRA) LIGHT SNOW SHOWERS TO THE REGION. THIS WILL BRING DOWN
CIGS/VIS TO IFR IN THE SIERRA WITH AREAS OF MVFR CIGS OUT INTO
WESTERN NEVADA. -SHSN SHOULD DISSIPATE QUICKLY BY AROUND 12Z/4AM
THURSDAY AS THE DISTURBANCE EXITS THE REGION.

AS FAR AS SNOWFALL ACCUMULATIONS ON UNTREATED PAVEMENTS/TARMACS,
SHOWERS SHOULD REMAIN LIGHT AND SPORADIC ENOUGH THAT WESTERN NEVADA
TERMINALS BELOW 5000 FEET REMAIN MAINLY WET, WITH A DUSTING POSSIBLE
ABOVE 5000 FEET (KRTS). IN THE NORTHERN SIERRA AND FOR NORTHEAST
CALIFORNIA (KSVE), SNOW COULD BE A BIT HEAVIER SO A LIGHT
ACCUMULATION (UP TO AN INCH) IS POSSIBLE ON UNTREATED PAVEMENT.

THURSDAY AND THURSDAY NIGHT, A RIDGE BUILDS OVERHEAD FOR DRIER
CONDITIONS BEFORE A COLD FRONT MOVES INTO EXTREME NORTHERN NEVADA
AND CALIFORNIA FRIDAY FOR ANOTHER SHOT AT MOUNTAIN SNOW AND VALLEY
RAIN. SNYDER

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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









000
FXUS65 KREV 172247
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
247 PM PST WED DEC 17 2014

.SYNOPSIS...

A WEAK AREA OF LOW PRESSURE MOVES ACROSS NORTHERN CALIFORNIA AND
WESTERN NEVADA TONIGHT AND EARLY THURSDAY. THIS LOW PRESSURE
SHOULD BRING ANOTHER ROUND OF LIGHT SNOW TO AREAS NORTH OF HIGHWAY
50 AND ALONG THE SIERRA CREST IN MONO COUNTY. ANOTHER SYSTEM WILL
IMPACT THE SAME AREAS FRIDAY WITH ANOTHER ROUND OF LIGHT SNOW. SLICK
AND SNOW COVERED ROADS ARE LIKELY FOR THE THE SIERRA PASSES
THROUGH FRIDAY. A FEW SLICK SPOTS ARE POSSIBLE THE LOWER VALLEYS
AS WELL THAT COULD IMPACT THE MORNING COMMUTE THURSDAY.

&&

.SHORT TERM...
NEXT WAVE IS MOVING TOWARD THE COAST NOW AND SHOULD IMPACT OUR
FORECAST AREA TONIGHT. THIS DOES NOT APPEAR TO BE AN OVERLY
STRONG WAVE...BUT THERE ENOUGH MOISTURE WITH IT TO PRODUCE LIGHT PCPN.
FORECAST MODELS DO NOT SHOW AN OVERWHELMING AMOUNT OF FORCING WITH
THIS SYSTEM. THERE IS A WARM AIR ADVECTION SIGNATURE WITH THE
SYSTEM THAT...COUPLED WITH FAIRLY DEEP MOISTURE...SHOULD PUSH PCPN
OVER THE SIERRA INTO WESTERN NEVADA OVERNIGHT.

THE BEST CHANCE FOR PCPN IN THE EVENING SHOULD BE IN NORTHEAST CA
FROM ABOUT THE TAHOE BASIN NORTHWARD. THEN THE PCPN CHANCES SPREAD
EAST AND SOUTH THROUGH THE OVERNIGHT HOURS. WITH WARM AIR ADVECTION
SYSTEMS LIKE THIS THE AMOUNT OF PCPN DOES NOT TEND TO BE VERY HIGH
OR DRIVEN MUCH BY TERRAIN INFLUENCES. THUS...IT IS NOT OUT OF THE
QUESTION FOR AREAS EAST OF THE SIERRA TO GET ABOUT AS MUCH AS
POINTS IN THE SIERRA AND FAR NORTHEAST CA. SNOW LEVELS COULD BE
DOWN TO EVEN THE LOWEST VALLEYS FLOORS IN THIS WARM AIR ADVECTION
AS WELL. FORECAST SOUNDINGS EAST OF THE SIERRA SHOW A DROP TO NEAR
4500 FEET FOR THE SNOW LEVELS LATE TONIGHT.

SO...WHAT DOES THIS MEAN FOR OVERNIGHT? HIGH POPS AND LOW QPF WITH
MAYBE UP TO AN INCH OF SNOW FOR AREAS OF WESTERN NEVADA. IN THE
TAHOE BASIN...NORTHEAST CA AND THE HIGHER ELEVATIONS OF MONO
COUNTY...SNOW AMOUNTS SHOULD BE AN INCH OR TWO EXCEPT IN THE
HIGHEST ELEVATIONS WHERE UP TO 4 INCHES IS POSSIBLE. SO...WE WILL
NOT PLAN ANY ADVISORIES AT THIS TIME...BUT BE ADVISED THAT EVEN AN
INCH OF SNOW COULD RESULT IN SLICK ROADS FOR THE MORNING COMMUTE.
BE PREPARED FOR A FEW TRAVEL DELAYS FOR THE THURSDAY MORNING
COMMUTE FOR EASTERN CA AND FAR WESTERN NV.

THIS WAVE MOVES EAST THURSDAY AFTERNOON WITH A FEW LINGERING
SHOWERS DURING THE DAY. A BRIEF PERIOD OF RIDGING DEVELOPS LATE
THURSDAY EVENING...BUT THIS IS QUICKLY REPLACED BY ANOTHER WAVE
MOVING ACROSS THE NORTHERN FORECAST AREA FRIDAY. 20

FRIDAY AND SATURDAY...
ANOTHER WAVE MOVES ACROSS NORTHERN CA/NV FRIDAY WITH A WEAK COLD
FRONT PUSHING ACROSS THE REGION LATE FRIDAY MORNING. THE FRONT
FALLS APART AS IT CROSSES THE NORTHERN SIERRA WITH THE WAVE
WEAKENING CONSIDERABLY EAST OF THE CREST. THEREFORE, DO NOT EXPECT
SIGNIFICANT RAIN/SNOW TO OCCUR. BEST CHANCES FOR PRECIPITATION
WILL BE ALONG THE SIERRA FROM TAHOE NORTH INTO NORTHEAST CA
EXTENDING INTO NORTHERN WASHOE COUNTY. INSTABILITY ACROSS NORTHERN
NV MAY LEAD TO PRECIPITATION DEVELOPING IN THE CENTRAL BASIN AND
RANGE AS WELL. MOST FORECAST GUIDANCE LARGELY SHADOWS OUT THE
SIERRA FRONT, BUT WITH WESTERLY FLOW THINK THAT A FEW SPOTS MAY
END UP SEEING SHOWERS SO HAVE KEPT IN LOW END CHANCES. THE SYSTEM
QUICKLY EXITS EASTWARD, BUT UPSLOPE FLOW MAY KEEP SHOWERS
LINGERING IN THE SIERRA. SNOW LEVELS WILL MAINLY BE 4500-5500 FEET
NORTH OF HIGHWAY 50 WITH 5500-6500 FEET SOUTH OF THERE WITH SLICK
ROADS AND TRAVEL IMPACTS POSSIBLE.

A DIRTY RIDGE BEGINS TO BUILD INTO THE WEST SATURDAY INTO SUNDAY
WITH WARM AIR ADVECTION PRECIPITATION DEVELOPING ACROSS NORTHERN
CA/NV. THE JET IS DRIVEN INTO THE PACIFIC NORTHWEST OVER THE TOP
OF THE RIDGE, BUT THERE IS SOME DISAGREEMENT JUST HOW FAR NORTH THE
JET CORE WILL BE. THIS WILL IMPACT HOW FAR SOUTH WE MAY SEE
RAIN/SNOW DEVELOP LATE SATURDAY INTO SUNDAY. THE NORTHERN END OF
THE RANGE IS NORTH OF A PORTOLA-LOVELOCK LINE WITH THE SOUTHERN
END OF THE SPECTRUM BEING DOWN TO MAMMOTH AND THE WHITE MOUNTAINS.
FOR NOW HAVE MAINTAINED SLIGHT CHANCE POPS AREA WIDE WITH CHANCE
POPS ACROSS FAR NORTHERN CA/NV TO ACCOUNT FOR THE UNCERTAINTY.
SNOW LEVELS WILL BE RISING IN THIS PATTERN TO 6000-7000 FEET. DJ

.LONG TERM...SUNDAY THROUGH WEDNESDAY/CHRISTMAS EVE...
SUNDAY THROUGH TUESDAY, EASTERN CALIFORNIA AND WESTERN NEVADA WILL
REMAIN UNDER AN UPPER RIDGE WHICH WILL STEER ANY DISTURBANCES INTO
THE PACIFIC NORTHWEST AND NORTHERN ROCKIES. THE RIDGE WILL BE RATHER
"DIRTY" WITH LOTS OF MID AND/OR HIGH CLOUDS, ESPECIALLY NORTH OF
INTERSTATE 80. TEMPERATURES SHOULD REMAIN MILD AT 5-10 DEGREES ABOVE
AVERAGE.

NEXT WEDNESDAY AND WEDNESDAY NIGHT (CHRISTMAS EVE), MODELS ARE
STARTING TO SHOW AN INTERESTING POSSIBILITY AS THE LARGE UPPER RIDGE
NEAR THE PACIFIC COAST BEGINS TO REBUILD/RETROGRADE INTO THE EASTERN
PACIFIC AND GULF OF ALASKA. THIS RETROGRESSION IS EXPECTED TO ALLOW
A SLIDER-TYPE SYSTEM TO DIVE DOWN INTO THE WESTERN CONUS BY LATE ON
CHRISTMAS EVE OR ON CHRISTMAS DAY/NEXT THURSDAY. ENSEMBLE SPREADS
ARE LARGE AT THIS TIME INDICATING VAST UNCERTAINTY, ALTHOUGH THE
UNCERTAINTY APPEARS TO BE RELATED TO THE STRENGTH AND HOW FAR SOUTH
THE SLIDER DIGS VERSUS WHETHER IT ACTUALLY EXISTS. THEREFORE, I
WOULD EXPECT SOME KIND OF SLIDER SYSTEM WITH INCREASING WINDS FOR
WEDNESDAY FOLLOWED BY COLDER TEMPERATURES FOR CHRISTMAS DAY. AS FAR
AS PRECIPITATION AND HOW COLD IT GETS, THAT REMAINS VERY UNCERTAIN
AT THIS TIME. STAY TUNED! SNYDER

&&

.AVIATION...
PLENTY OF MOISTURE AND A SLIGHTLY UNSTABLE ATMOSPHERE IS PRODUCING
WIDESPREAD CUMULUS ALONG WITH ISOLATED SHOWERS IN THE SIERRA AND OUT
INTO FAR WESTERN NEVADA THIS AFTERNOON. CLOUD DECKS ARE GENERALLY
VFR, ALTHOUGH AREAS OF TERRAIN OBSCUREMENT CAN BE FOUND IN EASTERN
CALIFORNIA/THE SIERRA AND IN SHOWERS ELSEWHERE.

TONIGHT (GENERALLY AFTER 03Z-06Z), YET ANOTHER WEAK UPPER
DISTURBANCE WILL MOVE OVER NORTHEAST CALIFORNIA AND WESTERN NEVADA.
THIS WILL BRING A ROUND OF SCATTERED (WESTERN NEVADA) TO NUMEROUS
(SIERRA) LIGHT SNOW SHOWERS TO THE REGION. THIS WILL BRING DOWN
CIGS/VIS TO IFR IN THE SIERRA WITH AREAS OF MVFR CIGS OUT INTO
WESTERN NEVADA. -SHSN SHOULD DISSIPATE QUICKLY BY AROUND 12Z/4AM
THURSDAY AS THE DISTURBANCE EXITS THE REGION.

AS FAR AS SNOWFALL ACCUMULATIONS ON UNTREATED PAVEMENTS/TARMACS,
SHOWERS SHOULD REMAIN LIGHT AND SPORADIC ENOUGH THAT WESTERN NEVADA
TERMINALS BELOW 5000 FEET REMAIN MAINLY WET, WITH A DUSTING POSSIBLE
ABOVE 5000 FEET (KRTS). IN THE NORTHERN SIERRA AND FOR NORTHEAST
CALIFORNIA (KSVE), SNOW COULD BE A BIT HEAVIER SO A LIGHT
ACCUMULATION (UP TO AN INCH) IS POSSIBLE ON UNTREATED PAVEMENT.

THURSDAY AND THURSDAY NIGHT, A RIDGE BUILDS OVERHEAD FOR DRIER
CONDITIONS BEFORE A COLD FRONT MOVES INTO EXTREME NORTHERN NEVADA
AND CALIFORNIA FRIDAY FOR ANOTHER SHOT AT MOUNTAIN SNOW AND VALLEY
RAIN. SNYDER

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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








000
FXUS65 KREV 171735
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
935 AM PST WED DEC 17 2014

.UPDATE...
CLOUDS HAVE THINNED A BIT MORE THAN FORECAST EAST OF THE SIERRA
TODAY WHILE SHOWERS ARE NOT QUITE AS WIDESPREAD IN THE SIERRA NOW.
HAVE REDUCED CLOUD COVER AND POPS EAST OF THE SIERRA FOR THE REST
OF THE DAY. THERE ARE SHOWERS WORKING THEIR WAY INTO THE WESTERN
SLOPES OF THE SIERRA NOW. THESE ARE IN MOIST FLOW BETWEEN AN
EXITING SHORT WAVE MOVING INTO NEVADA AND AN APPROACHING WAVE
MOVING TOWARD THE CA COAST. SHOWERS SHOULD INCREASE IN COVERAGE
LATER THIS AFTERNOON IN THE SIERRA AND NORTHEAST CA IN RESPONSE TO
THIS APPROACHING WAVE. 20

&&

.PREVIOUS DISCUSSION... /ISSUED 401 AM PST WED DEC 17 2014/

UPDATE...

QUICK UPDATE THIS MORNING TO INCLUDE SOME LAKE EFFECT SNOW SHOWERS
DEVELOPING OFF OF LAKE TAHOE. THE LIGHT SNOW BAND IS AROUND MOUNT
ROSE AND JUST NORTH OF WASHOE VALLEY. LIGHT SNOW ACCUMULATIONS
COULD MAKE FOR SOME SLICK DRIVING CONDITIONS THIS MORNING ON MOUNT
ROSE HIGHWAY AND I-580 BETWEEN RENO AND CARSON CITY. HOON

PREVIOUS DISCUSSION... /ISSUED 304 AM PST WED DEC 17 2014/

SYNOPSIS...

A WEAK SYSTEM EXITS THE REGION TODAY WITH RESIDUAL SHOWERS EXPECTED
ACROSS THE SIERRA AND PORTIONS OF NORTHEAST CALIFORNIA. ANOTHER WEAK
SYSTEM WILL PUSH INTO THE SIERRA AND WESTERN NEVADA TONIGHT BRINGING
THE NEXT ROUND OF LIGHT SNOW SHOWERS FOR THE HIGHER TERRAIN. SLICK
AND SNOW COVERED ROADS WILL IMPACT THE SIERRA PASSES THROUGH
FRIDAY.

SHORT TERM...
WEAK DISTURBANCE CURRENTLY MAKING ITS WAY ACROSS CALIFORNIA EARLY
THIS MORNING. A STRONGER JET AND SYSTEM UPSTREAM IS DIVING SOUTH AND
BREAKING UP/SPLITTING THE ENERGY WITH THIS FIRST WAVE AS IT
ENCOUNTERS THE SIERRA. THIS IS RESULTING IN THE BAND OF RAIN/SNOW
SHOWERS NEAR THE SIERRA TO FALL APART EARLY THIS MORNING, WITH
WARMING CLOUD TOPS ALSO INDICATING THE WEAKENING OF THE BAND. THE
BEST CHANCES FOR PRECIPITATION WILL BE SOUTH OF HIGHWAY 50 AS THE
SYSTEM CONTINUES TO GET SHOVED FURTHER SOUTH OF THE LAKE TAHOE
BASIN.

RESIDUAL SHOWERS WILL CONTINUE WITH MOIST UPSLOPE FLOW ACROSS
NORTHEASTERN CALIFORNIA AND THE SIERRA TODAY. THE LACK OF DYNAMICS
AND STRONG SOUTHWEST FLOW WILL RESULT IN MUCH OF THE PRECIPITATION
BEING SHADOWED OUT FOR WESTERN NEVADA THROUGH THE DAY, ALTHOUGH SOME
WEAK FLURRIES WILL BE POSSIBLE. THE NEXT WAVE WILL SWING THROUGH
THE AREA THIS EVENING INTO THURSDAY MORNING, BRINGING ANOTHER
ROUND OF LIGHT SNOW SHOWERS TO THE SIERRA. MAIN IMPACT WILL
CONTINUE TO BE INTERMITTENT DETERIORATING ROAD CONDITIONS ACROSS
SIERRA AND MOUNTAIN PASSES AS SNOW SHOWERS MOVE THROUGH THE REGION
THROUGH THURSDAY. KEEP UPDATED WITH ROAD CONDITIONS VIA NDOT AND
CALTRANS THROUGH THE END OF THE WEEK.

SHORTWAVE RIDGING WILL GIVE THE REGION A SHORT REPRIEVE FROM
PRECIPITATION WITH CLEARING SKIES AND LIGHT WINDS. THE NEXT SYSTEM
DROPS OUT OF THE GULF OF ALASKA AND ADVANCES TOWARDS THE REGION ON
FRIDAY AFTERNOON. NAM/ECMWF/GFS ALL HAVE SIMILAR TIMING WITH THE
COLD FRONT SWEEPING ACROSS THE REGION ON FRIDAY AFTERNOON. LIGHT
RAIN AND MOUNTAIN SNOW ARE LIKELY BY FRIDAY AFTERNOON, MAINLY NORTH
OF THE TAHOE BASIN AND INTERSTATE 80. PRECIPITATION AMOUNTS REMAIN
MODEST AT THIS TIME, AS JET ORIENTATION WILL NOT PROMOTE THE
DYNAMICS NEEDED FOR HIGHER AMOUNTS. STILL LOOKING AT AROUND A 0.10
TO 0.2 INCHES FROM PLUMAS-LASSEN-MODOC COUNTIES. THERE IS ALSO THE
POSSIBILITY THAT THE STRONG NORTH-SOUTH ORIENTED JET MAY RESULT IN
THE BULK OF THE SYSTEM`S DYNAMICS AND PRECIPITATION BEING DRIVEN
FURTHER SOUTH. OVERALL THIS IS NOT AN INCREDIBLY STRONG STORM, BUT
IT COULD BRING ANOTHER ROUND OF SNOW RESULTING IN CONTINUED WINTRY
ROAD CONDITIONS FOR THE SIERRA AND HIGHER TERRAIN. WEISHAHN

LONG TERM...SATURDAY THROUGH CHRISTMAS EVE...

BY SATURDAY, AN UPPER LEVEL RIDGE STARTS TO BUILD OVER THE
CALIFORNIA COAST. THIS LOOKS TO BE A DIRTY RIDGE, DUE TO WARM AIR
ADVECTION MOISTURE STREAMING INTO THE PACIFIC NORTHWEST AND CLIPPING
FAR NORTHERN CA/NV. THIS WILL KEEP SOME CLOUDS AROUND THROUGH THE
WEEKEND WITH CHANCES OF LIGHT RAIN/SNOW ON SATURDAY. MODELS ARE IN
GOOD AGREEMENT THAT THE RIDGE WILL AMPLIFY AS WE GO INTO NEXT WEEK,
BRINGING MILD AND DRY CONDITIONS. LIGHT WINDS AND VALLEY INVERSIONS
WILL ALSO LIKELY BRING AIR QUALITY ISSUES FOR EARLY NEXT WEEK AS
WELL. HOON

AVIATION...

LIGHT SNOW SHOWERS CONTINUE IN THE SIERRA THIS MORNING WITH MVFR CIG
FOR KTRK/KTVL/KMMH. LITTLE TO NO ACCUMULATION EXPECTED AS THIS STORM
WILL REMAIN MAINLY WEST OF THE SIERRA CREST. FOR KRNO/KCXP...A FEW
SHOWERS ARE POSSIBLE THIS MORNING, BUT RESTRICTIONS TO CIG/VIS ARE
UNLIKELY. MOUNTAIN OBSCURATION AND LIGHT TURBULENCE/ICING ARE ALSO
EXPECTED FOR TODAY. HOON

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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







000
FXUS65 KREV 171735
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
935 AM PST WED DEC 17 2014

.UPDATE...
CLOUDS HAVE THINNED A BIT MORE THAN FORECAST EAST OF THE SIERRA
TODAY WHILE SHOWERS ARE NOT QUITE AS WIDESPREAD IN THE SIERRA NOW.
HAVE REDUCED CLOUD COVER AND POPS EAST OF THE SIERRA FOR THE REST
OF THE DAY. THERE ARE SHOWERS WORKING THEIR WAY INTO THE WESTERN
SLOPES OF THE SIERRA NOW. THESE ARE IN MOIST FLOW BETWEEN AN
EXITING SHORT WAVE MOVING INTO NEVADA AND AN APPROACHING WAVE
MOVING TOWARD THE CA COAST. SHOWERS SHOULD INCREASE IN COVERAGE
LATER THIS AFTERNOON IN THE SIERRA AND NORTHEAST CA IN RESPONSE TO
THIS APPROACHING WAVE. 20

&&

.PREVIOUS DISCUSSION... /ISSUED 401 AM PST WED DEC 17 2014/

UPDATE...

QUICK UPDATE THIS MORNING TO INCLUDE SOME LAKE EFFECT SNOW SHOWERS
DEVELOPING OFF OF LAKE TAHOE. THE LIGHT SNOW BAND IS AROUND MOUNT
ROSE AND JUST NORTH OF WASHOE VALLEY. LIGHT SNOW ACCUMULATIONS
COULD MAKE FOR SOME SLICK DRIVING CONDITIONS THIS MORNING ON MOUNT
ROSE HIGHWAY AND I-580 BETWEEN RENO AND CARSON CITY. HOON

PREVIOUS DISCUSSION... /ISSUED 304 AM PST WED DEC 17 2014/

SYNOPSIS...

A WEAK SYSTEM EXITS THE REGION TODAY WITH RESIDUAL SHOWERS EXPECTED
ACROSS THE SIERRA AND PORTIONS OF NORTHEAST CALIFORNIA. ANOTHER WEAK
SYSTEM WILL PUSH INTO THE SIERRA AND WESTERN NEVADA TONIGHT BRINGING
THE NEXT ROUND OF LIGHT SNOW SHOWERS FOR THE HIGHER TERRAIN. SLICK
AND SNOW COVERED ROADS WILL IMPACT THE SIERRA PASSES THROUGH
FRIDAY.

SHORT TERM...
WEAK DISTURBANCE CURRENTLY MAKING ITS WAY ACROSS CALIFORNIA EARLY
THIS MORNING. A STRONGER JET AND SYSTEM UPSTREAM IS DIVING SOUTH AND
BREAKING UP/SPLITTING THE ENERGY WITH THIS FIRST WAVE AS IT
ENCOUNTERS THE SIERRA. THIS IS RESULTING IN THE BAND OF RAIN/SNOW
SHOWERS NEAR THE SIERRA TO FALL APART EARLY THIS MORNING, WITH
WARMING CLOUD TOPS ALSO INDICATING THE WEAKENING OF THE BAND. THE
BEST CHANCES FOR PRECIPITATION WILL BE SOUTH OF HIGHWAY 50 AS THE
SYSTEM CONTINUES TO GET SHOVED FURTHER SOUTH OF THE LAKE TAHOE
BASIN.

RESIDUAL SHOWERS WILL CONTINUE WITH MOIST UPSLOPE FLOW ACROSS
NORTHEASTERN CALIFORNIA AND THE SIERRA TODAY. THE LACK OF DYNAMICS
AND STRONG SOUTHWEST FLOW WILL RESULT IN MUCH OF THE PRECIPITATION
BEING SHADOWED OUT FOR WESTERN NEVADA THROUGH THE DAY, ALTHOUGH SOME
WEAK FLURRIES WILL BE POSSIBLE. THE NEXT WAVE WILL SWING THROUGH
THE AREA THIS EVENING INTO THURSDAY MORNING, BRINGING ANOTHER
ROUND OF LIGHT SNOW SHOWERS TO THE SIERRA. MAIN IMPACT WILL
CONTINUE TO BE INTERMITTENT DETERIORATING ROAD CONDITIONS ACROSS
SIERRA AND MOUNTAIN PASSES AS SNOW SHOWERS MOVE THROUGH THE REGION
THROUGH THURSDAY. KEEP UPDATED WITH ROAD CONDITIONS VIA NDOT AND
CALTRANS THROUGH THE END OF THE WEEK.

SHORTWAVE RIDGING WILL GIVE THE REGION A SHORT REPRIEVE FROM
PRECIPITATION WITH CLEARING SKIES AND LIGHT WINDS. THE NEXT SYSTEM
DROPS OUT OF THE GULF OF ALASKA AND ADVANCES TOWARDS THE REGION ON
FRIDAY AFTERNOON. NAM/ECMWF/GFS ALL HAVE SIMILAR TIMING WITH THE
COLD FRONT SWEEPING ACROSS THE REGION ON FRIDAY AFTERNOON. LIGHT
RAIN AND MOUNTAIN SNOW ARE LIKELY BY FRIDAY AFTERNOON, MAINLY NORTH
OF THE TAHOE BASIN AND INTERSTATE 80. PRECIPITATION AMOUNTS REMAIN
MODEST AT THIS TIME, AS JET ORIENTATION WILL NOT PROMOTE THE
DYNAMICS NEEDED FOR HIGHER AMOUNTS. STILL LOOKING AT AROUND A 0.10
TO 0.2 INCHES FROM PLUMAS-LASSEN-MODOC COUNTIES. THERE IS ALSO THE
POSSIBILITY THAT THE STRONG NORTH-SOUTH ORIENTED JET MAY RESULT IN
THE BULK OF THE SYSTEM`S DYNAMICS AND PRECIPITATION BEING DRIVEN
FURTHER SOUTH. OVERALL THIS IS NOT AN INCREDIBLY STRONG STORM, BUT
IT COULD BRING ANOTHER ROUND OF SNOW RESULTING IN CONTINUED WINTRY
ROAD CONDITIONS FOR THE SIERRA AND HIGHER TERRAIN. WEISHAHN

LONG TERM...SATURDAY THROUGH CHRISTMAS EVE...

BY SATURDAY, AN UPPER LEVEL RIDGE STARTS TO BUILD OVER THE
CALIFORNIA COAST. THIS LOOKS TO BE A DIRTY RIDGE, DUE TO WARM AIR
ADVECTION MOISTURE STREAMING INTO THE PACIFIC NORTHWEST AND CLIPPING
FAR NORTHERN CA/NV. THIS WILL KEEP SOME CLOUDS AROUND THROUGH THE
WEEKEND WITH CHANCES OF LIGHT RAIN/SNOW ON SATURDAY. MODELS ARE IN
GOOD AGREEMENT THAT THE RIDGE WILL AMPLIFY AS WE GO INTO NEXT WEEK,
BRINGING MILD AND DRY CONDITIONS. LIGHT WINDS AND VALLEY INVERSIONS
WILL ALSO LIKELY BRING AIR QUALITY ISSUES FOR EARLY NEXT WEEK AS
WELL. HOON

AVIATION...

LIGHT SNOW SHOWERS CONTINUE IN THE SIERRA THIS MORNING WITH MVFR CIG
FOR KTRK/KTVL/KMMH. LITTLE TO NO ACCUMULATION EXPECTED AS THIS STORM
WILL REMAIN MAINLY WEST OF THE SIERRA CREST. FOR KRNO/KCXP...A FEW
SHOWERS ARE POSSIBLE THIS MORNING, BUT RESTRICTIONS TO CIG/VIS ARE
UNLIKELY. MOUNTAIN OBSCURATION AND LIGHT TURBULENCE/ICING ARE ALSO
EXPECTED FOR TODAY. HOON

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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








000
FXUS65 KREV 171201 AAA
AFDREV

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RENO NV
401 AM PST WED DEC 17 2014

.UPDATE...

QUICK UPDATE THIS MORNING TO INCLUDE SOME LAKE EFFECT SNOW SHOWERS
DEVELOPING OFF OF LAKE TAHOE. THE LIGHT SNOW BAND IS AROUND MOUNT
ROSE AND JUST NORTH OF WASHOE VALLEY. LIGHT SNOW ACCUMULATIONS
COULD MAKE FOR SOME SLICK DRIVING CONDITIONS THIS MORNING ON MOUNT
ROSE HIGHWAY AND I-580 BETWEEN RENO AND CARSON CITY. HOON


&&

.PREVIOUS DISCUSSION... /ISSUED 304 AM PST WED DEC 17 2014/

SYNOPSIS...

A WEAK SYSTEM EXITS THE REGION TODAY WITH RESIDUAL SHOWERS EXPECTED
ACROSS THE SIERRA AND PORTIONS OF NORTHEAST CALIFORNIA. ANOTHER WEAK
SYSTEM WILL PUSH INTO THE SIERRA AND WESTERN NEVADA TONIGHT BRINGING
THE NEXT ROUND OF LIGHT SNOW SHOWERS FOR THE HIGHER TERRAIN. SLICK
AND SNOW COVERED ROADS WILL IMPACT THE SIERRA PASSES THROUGH
FRIDAY.

SHORT TERM...
WEAK DISTURBANCE CURRENTLY MAKING ITS WAY ACROSS CALIFORNIA EARLY
THIS MORNING. A STRONGER JET AND SYSTEM UPSTREAM IS DIVING SOUTH AND
BREAKING UP/SPLITTING THE ENERGY WITH THIS FIRST WAVE AS IT
ENCOUNTERS THE SIERRA. THIS IS RESULTING IN THE BAND OF RAIN/SNOW
SHOWERS NEAR THE SIERRA TO FALL APART EARLY THIS MORNING, WITH
WARMING CLOUD TOPS ALSO INDICATING THE WEAKENING OF THE BAND. THE
BEST CHANCES FOR PRECIPITATION WILL BE SOUTH OF HIGHWAY 50 AS THE
SYSTEM CONTINUES TO GET SHOVED FURTHER SOUTH OF THE LAKE TAHOE
BASIN.

RESIDUAL SHOWERS WILL CONTINUE WITH MOIST UPSLOPE FLOW ACROSS
NORTHEASTERN CALIFORNIA AND THE SIERRA TODAY. THE LACK OF DYNAMICS
AND STRONG SOUTHWEST FLOW WILL RESULT IN MUCH OF THE PRECIPITATION
BEING SHADOWED OUT FOR WESTERN NEVADA THROUGH THE DAY, ALTHOUGH SOME
WEAK FLURRIES WILL BE POSSIBLE. THE NEXT WAVE WILL SWING THROUGH
THE AREA THIS EVENING INTO THURSDAY MORNING, BRINGING ANOTHER
ROUND OF LIGHT SNOW SHOWERS TO THE SIERRA. MAIN IMPACT WILL
CONTINUE TO BE INTERMITTENT DETERIORATING ROAD CONDITIONS ACROSS
SIERRA AND MOUNTAIN PASSES AS SNOW SHOWERS MOVE THROUGH THE REGION
THROUGH THURSDAY. KEEP UPDATED WITH ROAD CONDITIONS VIA NDOT AND
CALTRANS THROUGH THE END OF THE WEEK.

SHORTWAVE RIDGING WILL GIVE THE REGION A SHORT REPRIEVE FROM
PRECIPITATION WITH CLEARING SKIES AND LIGHT WINDS. THE NEXT SYSTEM
DROPS OUT OF THE GULF OF ALASKA AND ADVANCES TOWARDS THE REGION ON
FRIDAY AFTERNOON. NAM/ECMWF/GFS ALL HAVE SIMILAR TIMING WITH THE
COLD FRONT SWEEPING ACROSS THE REGION ON FRIDAY AFTERNOON. LIGHT
RAIN AND MOUNTAIN SNOW ARE LIKELY BY FRIDAY AFTERNOON, MAINLY NORTH
OF THE TAHOE BASIN AND INTERSTATE 80. PRECIPITATION AMOUNTS REMAIN
MODEST AT THIS TIME, AS JET ORIENTATION WILL NOT PROMOTE THE
DYNAMICS NEEDED FOR HIGHER AMOUNTS. STILL LOOKING AT AROUND A 0.10
TO 0.2 INCHES FROM PLUMAS-LASSEN-MODOC COUNTIES. THERE IS ALSO THE
POSSIBILITY THAT THE STRONG NORTH-SOUTH ORIENTED JET MAY RESULT IN
THE BULK OF THE SYSTEM`S DYNAMICS AND PRECIPITATION BEING DRIVEN
FURTHER SOUTH. OVERALL THIS IS NOT AN INCREDIBLY STRONG STORM, BUT
IT COULD BRING ANOTHER ROUND OF SNOW RESULTING IN CONTINUED WINTRY
ROAD CONDITIONS FOR THE SIERRA AND HIGHER TERRAIN. WEISHAHN

LONG TERM...SATURDAY THROUGH CHRISTMAS EVE...

BY SATURDAY, AN UPPER LEVEL RIDGE STARTS TO BUILD OVER THE
CALIFORNIA COAST. THIS LOOKS TO BE A DIRTY RIDGE, DUE TO WARM AIR
ADVECTION MOISTURE STREAMING INTO THE PACIFIC NORTHWEST AND CLIPPING
FAR NORTHERN CA/NV. THIS WILL KEEP SOME CLOUDS AROUND THROUGH THE
WEEKEND WITH CHANCES OF LIGHT RAIN/SNOW ON SATURDAY. MODELS ARE IN
GOOD AGREEMENT THAT THE RIDGE WILL AMPLIFY AS WE GO INTO NEXT WEEK,
BRINGING MILD AND DRY CONDITIONS. LIGHT WINDS AND VALLEY INVERSIONS
WILL ALSO LIKELY BRING AIR QUALITY ISSUES FOR EARLY NEXT WEEK AS
WELL. HOON

AVIATION...

LIGHT SNOW SHOWERS CONTINUE IN THE SIERRA THIS MORNING WITH MVFR CIG
FOR KTRK/KTVL/KMMH. LITTLE TO NO ACCUMULATION EXPECTED AS THIS STORM
WILL REMAIN MAINLY WEST OF THE SIERRA CREST. FOR KRNO/KCXP...A FEW
SHOWERS ARE POSSIBLE THIS MORNING, BUT RESTRICTIONS TO CIG/VIS ARE
UNLIKELY. MOUNTAIN OBSCURATION AND LIGHT TURBULENCE/ICING ARE ALSO
EXPECTED FOR TODAY. HOON

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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







000
FXUS65 KREV 171201 AAA
AFDREV

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RENO NV
401 AM PST WED DEC 17 2014

.UPDATE...

QUICK UPDATE THIS MORNING TO INCLUDE SOME LAKE EFFECT SNOW SHOWERS
DEVELOPING OFF OF LAKE TAHOE. THE LIGHT SNOW BAND IS AROUND MOUNT
ROSE AND JUST NORTH OF WASHOE VALLEY. LIGHT SNOW ACCUMULATIONS
COULD MAKE FOR SOME SLICK DRIVING CONDITIONS THIS MORNING ON MOUNT
ROSE HIGHWAY AND I-580 BETWEEN RENO AND CARSON CITY. HOON


&&

.PREVIOUS DISCUSSION... /ISSUED 304 AM PST WED DEC 17 2014/

SYNOPSIS...

A WEAK SYSTEM EXITS THE REGION TODAY WITH RESIDUAL SHOWERS EXPECTED
ACROSS THE SIERRA AND PORTIONS OF NORTHEAST CALIFORNIA. ANOTHER WEAK
SYSTEM WILL PUSH INTO THE SIERRA AND WESTERN NEVADA TONIGHT BRINGING
THE NEXT ROUND OF LIGHT SNOW SHOWERS FOR THE HIGHER TERRAIN. SLICK
AND SNOW COVERED ROADS WILL IMPACT THE SIERRA PASSES THROUGH
FRIDAY.

SHORT TERM...
WEAK DISTURBANCE CURRENTLY MAKING ITS WAY ACROSS CALIFORNIA EARLY
THIS MORNING. A STRONGER JET AND SYSTEM UPSTREAM IS DIVING SOUTH AND
BREAKING UP/SPLITTING THE ENERGY WITH THIS FIRST WAVE AS IT
ENCOUNTERS THE SIERRA. THIS IS RESULTING IN THE BAND OF RAIN/SNOW
SHOWERS NEAR THE SIERRA TO FALL APART EARLY THIS MORNING, WITH
WARMING CLOUD TOPS ALSO INDICATING THE WEAKENING OF THE BAND. THE
BEST CHANCES FOR PRECIPITATION WILL BE SOUTH OF HIGHWAY 50 AS THE
SYSTEM CONTINUES TO GET SHOVED FURTHER SOUTH OF THE LAKE TAHOE
BASIN.

RESIDUAL SHOWERS WILL CONTINUE WITH MOIST UPSLOPE FLOW ACROSS
NORTHEASTERN CALIFORNIA AND THE SIERRA TODAY. THE LACK OF DYNAMICS
AND STRONG SOUTHWEST FLOW WILL RESULT IN MUCH OF THE PRECIPITATION
BEING SHADOWED OUT FOR WESTERN NEVADA THROUGH THE DAY, ALTHOUGH SOME
WEAK FLURRIES WILL BE POSSIBLE. THE NEXT WAVE WILL SWING THROUGH
THE AREA THIS EVENING INTO THURSDAY MORNING, BRINGING ANOTHER
ROUND OF LIGHT SNOW SHOWERS TO THE SIERRA. MAIN IMPACT WILL
CONTINUE TO BE INTERMITTENT DETERIORATING ROAD CONDITIONS ACROSS
SIERRA AND MOUNTAIN PASSES AS SNOW SHOWERS MOVE THROUGH THE REGION
THROUGH THURSDAY. KEEP UPDATED WITH ROAD CONDITIONS VIA NDOT AND
CALTRANS THROUGH THE END OF THE WEEK.

SHORTWAVE RIDGING WILL GIVE THE REGION A SHORT REPRIEVE FROM
PRECIPITATION WITH CLEARING SKIES AND LIGHT WINDS. THE NEXT SYSTEM
DROPS OUT OF THE GULF OF ALASKA AND ADVANCES TOWARDS THE REGION ON
FRIDAY AFTERNOON. NAM/ECMWF/GFS ALL HAVE SIMILAR TIMING WITH THE
COLD FRONT SWEEPING ACROSS THE REGION ON FRIDAY AFTERNOON. LIGHT
RAIN AND MOUNTAIN SNOW ARE LIKELY BY FRIDAY AFTERNOON, MAINLY NORTH
OF THE TAHOE BASIN AND INTERSTATE 80. PRECIPITATION AMOUNTS REMAIN
MODEST AT THIS TIME, AS JET ORIENTATION WILL NOT PROMOTE THE
DYNAMICS NEEDED FOR HIGHER AMOUNTS. STILL LOOKING AT AROUND A 0.10
TO 0.2 INCHES FROM PLUMAS-LASSEN-MODOC COUNTIES. THERE IS ALSO THE
POSSIBILITY THAT THE STRONG NORTH-SOUTH ORIENTED JET MAY RESULT IN
THE BULK OF THE SYSTEM`S DYNAMICS AND PRECIPITATION BEING DRIVEN
FURTHER SOUTH. OVERALL THIS IS NOT AN INCREDIBLY STRONG STORM, BUT
IT COULD BRING ANOTHER ROUND OF SNOW RESULTING IN CONTINUED WINTRY
ROAD CONDITIONS FOR THE SIERRA AND HIGHER TERRAIN. WEISHAHN

LONG TERM...SATURDAY THROUGH CHRISTMAS EVE...

BY SATURDAY, AN UPPER LEVEL RIDGE STARTS TO BUILD OVER THE
CALIFORNIA COAST. THIS LOOKS TO BE A DIRTY RIDGE, DUE TO WARM AIR
ADVECTION MOISTURE STREAMING INTO THE PACIFIC NORTHWEST AND CLIPPING
FAR NORTHERN CA/NV. THIS WILL KEEP SOME CLOUDS AROUND THROUGH THE
WEEKEND WITH CHANCES OF LIGHT RAIN/SNOW ON SATURDAY. MODELS ARE IN
GOOD AGREEMENT THAT THE RIDGE WILL AMPLIFY AS WE GO INTO NEXT WEEK,
BRINGING MILD AND DRY CONDITIONS. LIGHT WINDS AND VALLEY INVERSIONS
WILL ALSO LIKELY BRING AIR QUALITY ISSUES FOR EARLY NEXT WEEK AS
WELL. HOON

AVIATION...

LIGHT SNOW SHOWERS CONTINUE IN THE SIERRA THIS MORNING WITH MVFR CIG
FOR KTRK/KTVL/KMMH. LITTLE TO NO ACCUMULATION EXPECTED AS THIS STORM
WILL REMAIN MAINLY WEST OF THE SIERRA CREST. FOR KRNO/KCXP...A FEW
SHOWERS ARE POSSIBLE THIS MORNING, BUT RESTRICTIONS TO CIG/VIS ARE
UNLIKELY. MOUNTAIN OBSCURATION AND LIGHT TURBULENCE/ICING ARE ALSO
EXPECTED FOR TODAY. HOON

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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








000
FXUS65 KREV 171104
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
304 AM PST WED DEC 17 2014

.SYNOPSIS...

A WEAK SYSTEM EXITS THE REGION TODAY WITH RESIDUAL SHOWERS EXPECTED
ACROSS THE SIERRA AND PORTIONS OF NORTHEAST CALIFORNIA. ANOTHER WEAK
SYSTEM WILL PUSH INTO THE SIERRA AND WESTERN NEVADA TONIGHT BRINGING
THE NEXT ROUND OF LIGHT SNOW SHOWERS FOR THE HIGHER TERRAIN. SLICK
AND SNOW COVERED ROADS WILL IMPACT THE SIERRA PASSES THROUGH
FRIDAY.
&&

.SHORT TERM...
WEAK DISTURBANCE CURRENTLY MAKING ITS WAY ACROSS CALIFORNIA EARLY
THIS MORNING. A STRONGER JET AND SYSTEM UPSTREAM IS DIVING SOUTH AND
BREAKING UP/SPLITTING THE ENERGY WITH THIS FIRST WAVE AS IT
ENCOUNTERS THE SIERRA. THIS IS RESULTING IN THE BAND OF RAIN/SNOW
SHOWERS NEAR THE SIERRA TO FALL APART EARLY THIS MORNING, WITH
WARMING CLOUD TOPS ALSO INDICATING THE WEAKENING OF THE BAND. THE
BEST CHANCES FOR PRECIPITATION WILL BE SOUTH OF HIGHWAY 50 AS THE
SYSTEM CONTINUES TO GET SHOVED FURTHER SOUTH OF THE LAKE TAHOE
BASIN.

RESIDUAL SHOWERS WILL CONTINUE WITH MOIST UPSLOPE FLOW ACROSS
NORTHEASTERN CALIFORNIA AND THE SIERRA TODAY. THE LACK OF DYNAMICS
AND STRONG SOUTHWEST FLOW WILL RESULT IN MUCH OF THE PRECIPITATION
BEING SHADOWED OUT FOR WESTERN NEVADA THROUGH THE DAY, ALTHOUGH SOME
WEAK FLURRIES WILL BE POSSIBLE. THE NEXT WAVE WILL SWING THROUGH
THE AREA THIS EVENING INTO THURSDAY MORNING, BRINGING ANOTHER
ROUND OF LIGHT SNOW SHOWERS TO THE SIERRA. MAIN IMPACT WILL
CONTINUE TO BE INTERMITTENT DETERIORATING ROAD CONDITIONS ACROSS
SIERRA AND MOUNTAIN PASSES AS SNOW SHOWERS MOVE THROUGH THE REGION
THROUGH THURSDAY. KEEP UPDATED WITH ROAD CONDITIONS VIA NDOT AND
CALTRANS THROUGH THE END OF THE WEEK.

SHORTWAVE RIDGING WILL GIVE THE REGION A SHORT REPRIEVE FROM
PRECIPITATION WITH CLEARING SKIES AND LIGHT WINDS. THE NEXT SYSTEM
DROPS OUT OF THE GULF OF ALASKA AND ADVANCES TOWARDS THE REGION ON
FRIDAY AFTERNOON. NAM/ECMWF/GFS ALL HAVE SIMILAR TIMING WITH THE
COLD FRONT SWEEPING ACROSS THE REGION ON FRIDAY AFTERNOON. LIGHT
RAIN AND MOUNTAIN SNOW ARE LIKELY BY FRIDAY AFTERNOON, MAINLY NORTH
OF THE TAHOE BASIN AND INTERSTATE 80. PRECIPITATION AMOUNTS REMAIN
MODEST AT THIS TIME, AS JET ORIENTATION WILL NOT PROMOTE THE
DYNAMICS NEEDED FOR HIGHER AMOUNTS. STILL LOOKING AT AROUND A 0.10
TO 0.2 INCHES FROM PLUMAS-LASSEN-MODOC COUNTIES. THERE IS ALSO THE
POSSIBILITY THAT THE STRONG NORTH-SOUTH ORIENTED JET MAY RESULT IN
THE BULK OF THE SYSTEM`S DYNAMICS AND PRECIPITATION BEING DRIVEN
FURTHER SOUTH. OVERALL THIS IS NOT AN INCREDIBLY STRONG STORM, BUT
IT COULD BRING ANOTHER ROUND OF SNOW RESULTING IN CONTINUED WINTRY
ROAD CONDITIONS FOR THE SIERRA AND HIGHER TERRAIN. WEISHAHN

.LONG TERM...SATURDAY THROUGH CHRISTMAS EVE...

BY SATURDAY, AN UPPER LEVEL RIDGE STARTS TO BUILD OVER THE
CALIFORNIA COAST. THIS LOOKS TO BE A DIRTY RIDGE, DUE TO WARM AIR
ADVECTION MOISTURE STREAMING INTO THE PACIFIC NORTHWEST AND CLIPPING
FAR NORTHERN CA/NV. THIS WILL KEEP SOME CLOUDS AROUND THROUGH THE
WEEKEND WITH CHANCES OF LIGHT RAIN/SNOW ON SATURDAY. MODELS ARE IN
GOOD AGREEMENT THAT THE RIDGE WILL AMPLIFY AS WE GO INTO NEXT WEEK,
BRINGING MILD AND DRY CONDITIONS. LIGHT WINDS AND VALLEY INVERSIONS
WILL ALSO LIKELY BRING AIR QUALITY ISSUES FOR EARLY NEXT WEEK AS
WELL. HOON

&&

.AVIATION...

LIGHT SNOW SHOWERS CONTINUE IN THE SIERRA THIS MORNING WITH MVFR CIG
FOR KTRK/KTVL/KMMH. LITTLE TO NO ACCUMULATION EXPECTED AS THIS STORM
WILL REMAIN MAINLY WEST OF THE SIERRA CREST. FOR KRNO/KCXP...A FEW
SHOWERS ARE POSSIBLE THIS MORNING, BUT RESTRICTIONS TO CIG/VIS ARE
UNLIKELY. MOUNTAIN OBSCURATION AND LIGHT TURBULENCE/ICING ARE ALSO
EXPECTED FOR TODAY. HOON

&&


.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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







000
FXUS65 KREV 170626
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
1026 PM PST TUE DEC 16 2014

.UPDATE...
BAND OF PRECIPITATION OVER THE SACRAMENTO VALLEY HAS BEEN THINNING
OUT OVER THE LAST HOUR, WITH SATELLITE DATA SHOWING WARMING CLOUD
TOPS. SO FAR ONLY LIGHT SNOW HAS OCCURRED THIS ALONG THE SIERRA
CREST AND ACROSS NORTHEAST CALIFORNIA. MOST ROADS APPEAR TO BE
WET BASED ON WEB CAMS WITH SNOW STICKING TO ROADS ABOVE 6500-7000
FEET. SLICK AND ICY CONDITIONS WILL STILL IMPACT TRAVEL ON I-80,
US-50, CA-36, 49, 89 AND 88 TONIGHT.

LATEST MODELS SUGGEST THIS BAND WILL CONTINUE TO THIN AND DISPERSE
INTO SHOWERS AS IT SLOWLY MOVES UP THE WESTERN SLOPES NORTH OF
HIGHWAY 88/CARSON PASS. THIS WILL LIKELY LEAVE VERY LITTLE IN THE
WAY OF ACCUMULATION EAST OF THE CREST, ESPECIALLY IN THE TAHOE
BASIN. SOUTH OF CARSON PASS THERE IS MORE LIFT AND INSTABILITY IN
THE MODELS, SO THE HIGHEST ACCUMULATIONS SHOULD OCCUR ALONG THE
CREST IN MONO COUNTY WHERE 4-8 INCHES ARE POSSIBLE BY WEDNESDAY
MORNING. BRONG

&&

.SYNOPSIS...

LOW PRESSURE SYSTEMS WILL BRING PERIODS OF SNOW TO THE SIERRA AND
PORTIONS OF WESTERN NEVADA TONIGHT AND FRIDAY. ALTHOUGH HEAVY
SNOW IS UNLIKELY, SLICK DRIVING CONDITIONS WILL IMPACT THE SIERRA
AND PORTIONS OF NORTHEAST CALIFORNIA LATE TONIGHT AND WEDNESDAY.

&&

.PREVIOUS DISCUSSION... /ISSUED 257 PM PST TUE DEC 16 2014/

SHORT TERM...

THE NEXT DISTURBANCE IN OUR SERIES OF WEAK DISTURBANCES IS CURRENTLY
APPROACHING THE NORTHERN AND CENTRAL CALIFORNIA COAST. THIS IMPULSE
WILL MOVE INTO THE SIERRA AND WESTERN NEVADA LATE TONIGHT AND
WEDNESDAY MORNING. UNFORTUNATELY, WHILE THE PRECIPITATION CURRENTLY
LOOKS GOOD COMING INTO THE COAST A BACKSIDE JET STREAK IS EXPECTED
TO CAUSE THE TROUGH TO ELONGATE AND SPLIT AS IT MOVES INLAND OVERNIGHT.
IN ADDITION, FLOW ALOFT WILL BACK TO A MORE SOUTHERLY DIRECTION
TONIGHT WHICH IS LESS FAVORABLE FOR UPSLOPE FORCING FOR PRECIPITATION
IN THE NORTHERN SIERRA. WHILE THE FLOW WILL EVENTUALLY TURN MORE
SOUTHWEST-WEST IN THE SIERRA FOR BETTER OROGRAPHIC FORCING, IT
WILL BE NEAR TROUGH PASSAGE SO THE POTENTIAL FOR A PERIOD OF HEAVIER
SNOW WILL BE LIMITED TO A FEW HOURS EARLY WEDNESDAY MORNING.

THE WEAKENING FORCING WILL NOT PREVENT THE SIERRA AND NORTHEAST
CALIFORNIA (ABOVE ~4500 FEET) FROM RECEIVING SOME SNOWFALL LATE
TONIGHT AND ON WEDNESDAY. HOWEVER, IT SHOULD CUT DOWN THE PRECIPITATION
SUCH THAT SNOWFALL WILL REMAIN RELATIVELY LIGHT FOR THE EASTERN
SIERRA. THEREFORE, WE HAVE DECIDED THAT A WINTER WEATHER ADVISORY
IS UNNECESSARY AND WILL RELY ON HEADS UP GRAPHICS AND SOCIAL MEDIA
POSTS TO GET THE WORD OUT THAT TRAVEL RESTRICTIONS ARE LIKELY FOR
SIERRA AND NORTHEAST CALIFORNIA ROADS. REMEMBER: THE LACK OF AN
ADVISORY DOES NOT MEAN THERE WILL NOT BE SOME IMPACTS SO PAY
ATTENTION TO THE FORECAST, WEBPAGE GRAPHICS AND SOCIAL MEDIA POSTS
TO STAY ABREAST OF THE LATEST IMPACTS.

THE WEAK DISTURBANCE SLIDES TO THE EAST WEDNESDAY AFTERNOON FOR AN
END (BASIN AND RANGE), OR AT LEAST A REDUCTION TO VERY LIGHT SHOWERS
(SIERRA) FOR THE REGION. WEDNESDAY NIGHT, SOME MODELS BEGIN TO BUILD
AN UPPER RIDGE OVERHEAD. HOWEVER, THE GFS AND TO A LESSER EXTENT THE
ECMWF BRING ONE MORE PARTING SHOT OF SHOWERS (WITH WARM AIR ADVECTION)
TO NORTHEAST CALIFORNIA AND FAR NORTHWEST NEVADA BEFORE THE RIDGE
BUILDS OVERHEAD ON THURSDAY. ANY PRECIPITATION WOULD REMAIN QUITE
LIGHT SO IMPACTS SHOULD BE LIMITED. SNYDER

LONG TERM...FRIDAY THROUGH TUESDAY...

MODEL GUIDANCE CONTINUES TO SHOW A SHORTWAVE EJECTING FROM A GULF
OF ALASKA LOW, SWINGING ACROSS NORTHERN CA/NV FRIDAY. LIGHT RAIN
AND MOUNTAIN SNOW IS LIKELY BY FRIDAY AFTERNOON NORTH OF THE TAHOE
BASIN, WITH LIQUID AMOUNTS 0.10-0.20 INCHES EXPECTED ACROSS
PLUMAS/LASSEN/MODOC COUNTIES. THERE CONTINUE TO BE MODEL
DIFFERENCES REGARDING UPPER JET SUPPORT FRIDAY NIGHT WITH THE
DRIEST FORECASTS SHOWING LITTLE OR NO PRECIPITATION SOUTH OF
WA/OR. HOWEVER, THE 12Z ECMWF MODEL NOW HAS STRONGER JET SUPPORT
AND INDICATES A FEW INCHES OF SNOW COULD SPREAD AS FAR SOUTH AS
THE TAHOE BASIN FRIDAY NIGHT. GIVEN THE MODEL DIFFERENCES AND
BECAUSE THIS IS NOT A STRONG STORM, WE MAINTAINED CHANCE POPS
FRIDAY NIGHT ACROSS THE SIERRA AND WESTERN NV FOR NOW.

FOR SATURDAY, THE ENTRANCE REGION OF A NORTHERLY UPPER JET WARRANTS
A SLIGHT CHANCE FOR LIGHT RAIN AND MOUNTAIN SNOW SHOWERS ACROSS THE
EASTERN SIERRA AND WESTERN NV. FOR THE SUNDAY-TUESDAY PERIOD, A
RIDGE OF HIGH PRESSURE LOOKS TO BUILD OVER CA/NV BRINGING DRY/STABLE
CONDITIONS AND LIGHT WINDS. AS SUCH, VALLEY INVERSIONS AND AIR
QUALITY ISSUES ARE POSSIBLE EARLY NEXT WEEK. JCM

AVIATION...

ANOTHER WEAK WAVE MOVES THROUGH THE SIERRA TONIGHT. EXPECT LIGHT
SHOWERS AT KTRK/KTVL/KMMH AFTER 03Z-06Z, WITH IFR CONDITIONS DUE
TO SNOW EXPECTED FROM 06Z-15Z WEDNESDAY. FOR ACCUMULATIONS, 2-4"
OF SNOW ARE POSSIBLE AT KTRK/KTVL/KMMH BY WEDNESDAY MORNING. FOR
KRNO/KCXP...A FEW SHOWERS ARE POSSIBLE TONIGHT BUT RESTRICTIONS
TO CIG/VIS ARE UNLIKELY. MOUNTAIN OBSCURATION AND ICING ARE ALSO
EXPECTED LATE TONIGHT INTO WEDNESDAY MORNING. JCM

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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







000
FXUS65 KREV 170626
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
1026 PM PST TUE DEC 16 2014

.UPDATE...
BAND OF PRECIPITATION OVER THE SACRAMENTO VALLEY HAS BEEN THINNING
OUT OVER THE LAST HOUR, WITH SATELLITE DATA SHOWING WARMING CLOUD
TOPS. SO FAR ONLY LIGHT SNOW HAS OCCURRED THIS ALONG THE SIERRA
CREST AND ACROSS NORTHEAST CALIFORNIA. MOST ROADS APPEAR TO BE
WET BASED ON WEB CAMS WITH SNOW STICKING TO ROADS ABOVE 6500-7000
FEET. SLICK AND ICY CONDITIONS WILL STILL IMPACT TRAVEL ON I-80,
US-50, CA-36, 49, 89 AND 88 TONIGHT.

LATEST MODELS SUGGEST THIS BAND WILL CONTINUE TO THIN AND DISPERSE
INTO SHOWERS AS IT SLOWLY MOVES UP THE WESTERN SLOPES NORTH OF
HIGHWAY 88/CARSON PASS. THIS WILL LIKELY LEAVE VERY LITTLE IN THE
WAY OF ACCUMULATION EAST OF THE CREST, ESPECIALLY IN THE TAHOE
BASIN. SOUTH OF CARSON PASS THERE IS MORE LIFT AND INSTABILITY IN
THE MODELS, SO THE HIGHEST ACCUMULATIONS SHOULD OCCUR ALONG THE
CREST IN MONO COUNTY WHERE 4-8 INCHES ARE POSSIBLE BY WEDNESDAY
MORNING. BRONG

&&

.SYNOPSIS...

LOW PRESSURE SYSTEMS WILL BRING PERIODS OF SNOW TO THE SIERRA AND
PORTIONS OF WESTERN NEVADA TONIGHT AND FRIDAY. ALTHOUGH HEAVY
SNOW IS UNLIKELY, SLICK DRIVING CONDITIONS WILL IMPACT THE SIERRA
AND PORTIONS OF NORTHEAST CALIFORNIA LATE TONIGHT AND WEDNESDAY.

&&

.PREVIOUS DISCUSSION... /ISSUED 257 PM PST TUE DEC 16 2014/

SHORT TERM...

THE NEXT DISTURBANCE IN OUR SERIES OF WEAK DISTURBANCES IS CURRENTLY
APPROACHING THE NORTHERN AND CENTRAL CALIFORNIA COAST. THIS IMPULSE
WILL MOVE INTO THE SIERRA AND WESTERN NEVADA LATE TONIGHT AND
WEDNESDAY MORNING. UNFORTUNATELY, WHILE THE PRECIPITATION CURRENTLY
LOOKS GOOD COMING INTO THE COAST A BACKSIDE JET STREAK IS EXPECTED
TO CAUSE THE TROUGH TO ELONGATE AND SPLIT AS IT MOVES INLAND OVERNIGHT.
IN ADDITION, FLOW ALOFT WILL BACK TO A MORE SOUTHERLY DIRECTION
TONIGHT WHICH IS LESS FAVORABLE FOR UPSLOPE FORCING FOR PRECIPITATION
IN THE NORTHERN SIERRA. WHILE THE FLOW WILL EVENTUALLY TURN MORE
SOUTHWEST-WEST IN THE SIERRA FOR BETTER OROGRAPHIC FORCING, IT
WILL BE NEAR TROUGH PASSAGE SO THE POTENTIAL FOR A PERIOD OF HEAVIER
SNOW WILL BE LIMITED TO A FEW HOURS EARLY WEDNESDAY MORNING.

THE WEAKENING FORCING WILL NOT PREVENT THE SIERRA AND NORTHEAST
CALIFORNIA (ABOVE ~4500 FEET) FROM RECEIVING SOME SNOWFALL LATE
TONIGHT AND ON WEDNESDAY. HOWEVER, IT SHOULD CUT DOWN THE PRECIPITATION
SUCH THAT SNOWFALL WILL REMAIN RELATIVELY LIGHT FOR THE EASTERN
SIERRA. THEREFORE, WE HAVE DECIDED THAT A WINTER WEATHER ADVISORY
IS UNNECESSARY AND WILL RELY ON HEADS UP GRAPHICS AND SOCIAL MEDIA
POSTS TO GET THE WORD OUT THAT TRAVEL RESTRICTIONS ARE LIKELY FOR
SIERRA AND NORTHEAST CALIFORNIA ROADS. REMEMBER: THE LACK OF AN
ADVISORY DOES NOT MEAN THERE WILL NOT BE SOME IMPACTS SO PAY
ATTENTION TO THE FORECAST, WEBPAGE GRAPHICS AND SOCIAL MEDIA POSTS
TO STAY ABREAST OF THE LATEST IMPACTS.

THE WEAK DISTURBANCE SLIDES TO THE EAST WEDNESDAY AFTERNOON FOR AN
END (BASIN AND RANGE), OR AT LEAST A REDUCTION TO VERY LIGHT SHOWERS
(SIERRA) FOR THE REGION. WEDNESDAY NIGHT, SOME MODELS BEGIN TO BUILD
AN UPPER RIDGE OVERHEAD. HOWEVER, THE GFS AND TO A LESSER EXTENT THE
ECMWF BRING ONE MORE PARTING SHOT OF SHOWERS (WITH WARM AIR ADVECTION)
TO NORTHEAST CALIFORNIA AND FAR NORTHWEST NEVADA BEFORE THE RIDGE
BUILDS OVERHEAD ON THURSDAY. ANY PRECIPITATION WOULD REMAIN QUITE
LIGHT SO IMPACTS SHOULD BE LIMITED. SNYDER

LONG TERM...FRIDAY THROUGH TUESDAY...

MODEL GUIDANCE CONTINUES TO SHOW A SHORTWAVE EJECTING FROM A GULF
OF ALASKA LOW, SWINGING ACROSS NORTHERN CA/NV FRIDAY. LIGHT RAIN
AND MOUNTAIN SNOW IS LIKELY BY FRIDAY AFTERNOON NORTH OF THE TAHOE
BASIN, WITH LIQUID AMOUNTS 0.10-0.20 INCHES EXPECTED ACROSS
PLUMAS/LASSEN/MODOC COUNTIES. THERE CONTINUE TO BE MODEL
DIFFERENCES REGARDING UPPER JET SUPPORT FRIDAY NIGHT WITH THE
DRIEST FORECASTS SHOWING LITTLE OR NO PRECIPITATION SOUTH OF
WA/OR. HOWEVER, THE 12Z ECMWF MODEL NOW HAS STRONGER JET SUPPORT
AND INDICATES A FEW INCHES OF SNOW COULD SPREAD AS FAR SOUTH AS
THE TAHOE BASIN FRIDAY NIGHT. GIVEN THE MODEL DIFFERENCES AND
BECAUSE THIS IS NOT A STRONG STORM, WE MAINTAINED CHANCE POPS
FRIDAY NIGHT ACROSS THE SIERRA AND WESTERN NV FOR NOW.

FOR SATURDAY, THE ENTRANCE REGION OF A NORTHERLY UPPER JET WARRANTS
A SLIGHT CHANCE FOR LIGHT RAIN AND MOUNTAIN SNOW SHOWERS ACROSS THE
EASTERN SIERRA AND WESTERN NV. FOR THE SUNDAY-TUESDAY PERIOD, A
RIDGE OF HIGH PRESSURE LOOKS TO BUILD OVER CA/NV BRINGING DRY/STABLE
CONDITIONS AND LIGHT WINDS. AS SUCH, VALLEY INVERSIONS AND AIR
QUALITY ISSUES ARE POSSIBLE EARLY NEXT WEEK. JCM

AVIATION...

ANOTHER WEAK WAVE MOVES THROUGH THE SIERRA TONIGHT. EXPECT LIGHT
SHOWERS AT KTRK/KTVL/KMMH AFTER 03Z-06Z, WITH IFR CONDITIONS DUE
TO SNOW EXPECTED FROM 06Z-15Z WEDNESDAY. FOR ACCUMULATIONS, 2-4"
OF SNOW ARE POSSIBLE AT KTRK/KTVL/KMMH BY WEDNESDAY MORNING. FOR
KRNO/KCXP...A FEW SHOWERS ARE POSSIBLE TONIGHT BUT RESTRICTIONS
TO CIG/VIS ARE UNLIKELY. MOUNTAIN OBSCURATION AND ICING ARE ALSO
EXPECTED LATE TONIGHT INTO WEDNESDAY MORNING. JCM

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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








000
FXUS65 KREV 162257
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
257 PM PST TUE DEC 16 2014

.SYNOPSIS...

TWO WEAK WEATHER SYSTEMS WILL BRING PERIODS OF SNOW TO THE SIERRA
AND PORTIONS OF WESTERN NEVADA THROUGH FRIDAY, WITH THE FIRST
SYSTEM ARRIVING TONIGHT AND WEDNESDAY MORNING. ALTHOUGH HEAVY SNOW
IS NOT EXPECTED, SLICK DRIVING CONDITIONS WILL IMPACT THE SIERRA
AND PORTIONS OF NORTHEAST CALIFORNIA LATE TONIGHT AND WEDNESDAY.

&&

.SHORT TERM...

THE NEXT DISTURBANCE IN OUR SERIES OF WEAK DISTURBANCES IS CURRENTLY
APPROACHING THE NORTHERN AND CENTRAL CALIFORNIA COAST. THIS IMPULSE
WILL MOVE INTO THE SIERRA AND WESTERN NEVADA LATE TONIGHT AND
WEDNESDAY MORNING. UNFORTUNATELY, WHILE THE PRECIPITATION CURRENTLY
LOOKS GOOD COMING INTO THE COAST A BACKSIDE JET STREAK IS EXPECTED
TO CAUSE THE TROUGH TO ELONGATE AND SPLIT AS IT MOVES INLAND OVERNIGHT.
IN ADDITION, FLOW ALOFT WILL BACK TO A MORE SOUTHERLY DIRECTION
TONIGHT WHICH IS LESS FAVORABLE FOR UPSLOPE FORCING FOR PRECIPITATION
IN THE NORTHERN SIERRA. WHILE THE FLOW WILL EVENTUALLY TURN MORE
SOUTHWEST-WEST IN THE SIERRA FOR BETTER OROGRAPHIC FORCING, IT
WILL BE NEAR TROUGH PASSAGE SO THE POTENTIAL FOR A PERIOD OF HEAVIER
SNOW WILL BE LIMITED TO A FEW HOURS EARLY WEDNESDAY MORNING.

THE WEAKENING FORCING WILL NOT PREVENT THE SIERRA AND NORTHEAST
CALIFORNIA (ABOVE ~4500 FEET) FROM RECEIVING SOME SNOWFALL LATE
TONIGHT AND ON WEDNESDAY. HOWEVER, IT SHOULD CUT DOWN THE PRECIPITATION
SUCH THAT SNOWFALL WILL REMAIN RELATIVELY LIGHT FOR THE EASTERN
SIERRA. THEREFORE, WE HAVE DECIDED THAT A WINTER WEATHER ADVISORY
IS UNNECESSARY AND WILL RELY ON HEADS UP GRAPHICS AND SOCIAL MEDIA
POSTS TO GET THE WORD OUT THAT TRAVEL RESTRICTIONS ARE LIKELY FOR
SIERRA AND NORTHEAST CALIFORNIA ROADS. REMEMBER: THE LACK OF AN
ADVISORY DOES NOT MEAN THERE WILL NOT BE SOME IMPACTS SO PAY
ATTENTION TO THE FORECAST, WEBPAGE GRAPHICS AND SOCIAL MEDIA POSTS
TO STAY ABREAST OF THE LATEST IMPACTS.

THE WEAK DISTURBANCE SLIDES TO THE EAST WEDNESDAY AFTERNOON FOR AN
END (BASIN AND RANGE), OR AT LEAST A REDUCTION TO VERY LIGHT SHOWERS
(SIERRA) FOR THE REGION. WEDNESDAY NIGHT, SOME MODELS BEGIN TO BUILD
AN UPPER RIDGE OVERHEAD. HOWEVER, THE GFS AND TO A LESSER EXTENT THE
ECMWF BRING ONE MORE PARTING SHOT OF SHOWERS (WITH WARM AIR ADVECTION)
TO NORTHEAST CALIFORNIA AND FAR NORTHWEST NEVADA BEFORE THE RIDGE
BUILDS OVERHEAD ON THURSDAY. ANY PRECIPITATION WOULD REMAIN QUITE
LIGHT SO IMPACTS SHOULD BE LIMITED. SNYDER

.LONG TERM...FRIDAY THROUGH TUESDAY...

MODEL GUIDANCE CONTINUES TO SHOW A SHORTWAVE EJECTING FROM A GULF
OF ALASKA LOW, SWINGING ACROSS NORTHERN CA/NV FRIDAY. LIGHT RAIN
AND MOUNTAIN SNOW IS LIKELY BY FRIDAY AFTERNOON NORTH OF THE TAHOE
BASIN, WITH LIQUID AMOUNTS 0.10-0.20 INCHES EXPECTED ACROSS
PLUMAS/LASSEN/MODOC COUNTIES. THERE CONTINUE TO BE MODEL
DIFFERENCES REGARDING UPPER JET SUPPORT FRIDAY NIGHT WITH THE
DRIEST FORECASTS SHOWING LITTLE OR NO PRECIPITATION SOUTH OF
WA/OR. HOWEVER, THE 12Z ECMWF MODEL NOW HAS STRONGER JET SUPPORT
AND INDICATES A FEW INCHES OF SNOW COULD SPREAD AS FAR SOUTH AS
THE TAHOE BASIN FRIDAY NIGHT. GIVEN THE MODEL DIFFERENCES AND
BECAUSE THIS IS NOT A STRONG STORM, WE MAINTAINED CHANCE POPS
FRIDAY NIGHT ACROSS THE SIERRA AND WESTERN NV FOR NOW.

FOR SATURDAY, THE ENTRANCE REGION OF A NORTHERLY UPPER JET WARRANTS
A SLIGHT CHANCE FOR LIGHT RAIN AND MOUNTAIN SNOW SHOWERS ACROSS THE
EASTERN SIERRA AND WESTERN NV. FOR THE SUNDAY-TUESDAY PERIOD, A
RIDGE OF HIGH PRESSURE LOOKS TO BUILD OVER CA/NV BRINGING DRY/STABLE
CONDITIONS AND LIGHT WINDS. AS SUCH, VALLEY INVERSIONS AND AIR
QUALITY ISSUES ARE POSSIBLE EARLY NEXT WEEK. JCM

&&

.AVIATION...

ANOTHER WEAK WAVE MOVES THROUGH THE SIERRA TONIGHT. EXPECT LIGHT
SHOWERS AT KTRK/KTVL/KMMH AFTER 03Z-06Z, WITH IFR CONDITIONS DUE
TO SNOW EXPECTED FROM 06Z-15Z WEDNESDAY. FOR ACCUMULATIONS, 2-4"
OF SNOW ARE POSSIBLE AT KTRK/KTVL/KMMH BY WEDNESDAY MORNING. FOR
KRNO/KCXP...A FEW SHOWERS ARE POSSIBLE TONIGHT BUT RESTRICTIONS
TO CIG/VIS ARE UNLIKELY. MOUNTAIN OBSCURATION AND ICING ARE ALSO
EXPECTED LATE TONIGHT INTO WEDNESDAY MORNING. JCM

&&


.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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









000
FXUS65 KREV 161759
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
959 AM PST TUE DEC 16 2014

.UPDATE...
UPDATED THROUGH THIS EVENING, MAINLY TO LOWER SKY COVER IN THE
BASIN SOUTH OF GERLACH AND TO REMOVE AFTERNOON SHOWERS OUTSIDE OF
EASTERN CALIFORNIA. THE UPPER IMPULSE THAT AFFECTED THE REGION
LAST NIGHT HAS MOVED INTO NEVADA RESULTING IN A WEAKENING OR
DISSIPATION OF SHOWERS FOR MOST AREAS EAST OF THE SIERRA CREST.

THE NEXT DISTURBANCE DUE IN LATE TONIGHT CONTINUES TO LOOK WEAK
AND ELONGATED ALTHOUGH TRAVEL ISSUES (CHAIN REQUIREMENTS) ARE
STILL LIKELY IN THE SIERRA AND FOR PORTIONS OF LASSEN AND EASTERN
PLUMAS COUNTIES LATE TONIGHT AND WEDNESDAY MORNING WITH THE
EXPECTED, BUT RELATIVELY LIGHT, SNOWFALL. SNYDER

&&

.SYNOPSIS...
A SERIES OF WEAK WEATHER SYSTEMS WILL BRING PERIODS OF SNOW TO THE
SIERRA AND WESTERN NEVADA THIS WEEK. ALTHOUGH HEAVY SNOW IS NOT
EXPECTED, SLICK DRIVING CONDITIONS WILL LIKELY IMPACT THE PEAK
MORNING AND EVENING COMMUTE TIMES THROUGH WEDNESDAY. ANOTHER ROUND
OF LIGHT SNOW AND RAIN IS POSSIBLE FRIDAY AND FRIDAY NIGHT.

&&

.PREVIOUS DISCUSSION... /ISSUED 411 AM PST TUE DEC 16 2014/

SHORT TERM...

AREAS OF LIGHT SNOW OVERNIGHT HAVE PRODUCED SLICK AND ICY
CONDITIONS OVER MANY SIERRA HIGHWAYS, WITH WIDESPREAD CHAIN CONTROLS
IN PLACE AS OF EARLY THIS MORNING. A NARROW BAND OF LAKE EFFECT SNOW
SHOWERS ORIGINATING FROM TAHOE HAS ALSO PRODUCED SLICK CONDITIONS
AND CHAIN RESTRICTIONS ON I-580 AND BOWERS MANSION ROAD BETWEEN RENO
AND CARSON CITY. SLOW DOWN AND USE EXTRA CAUTION AS SLICK ROADS WILL
PERSIST FOR THE MORNING COMMUTE.

WEAK VORTICITY CENTER MOVING ACROSS THE CENTRAL SIERRA WILL KEEP
BANDS OF SNOW SHOWERS GOING UNTIL AROUND DAYBREAK. WHILE MOST OF
THE SHOWERS WILL REMAIN NEAR THE SIERRA CREST, SCATTERED BRIEF SNOW
SHOWERS WILL MAKE THEIR WAY INTO LOWER ELEVATIONS OF WESTERN NV
AND NORTHEAST CA. MOST ACTIVITY WILL DIMINISH LATER THIS MORNING
AS DYNAMICS WEAKEN AFTER THIS SYSTEM MOVES EAST OF THE REGION.
SNOW ACCUMULATIONS WILL BE MORE LOCALIZED COMPARED TO YESTERDAY.
IF A BAND IS ABLE TO PERSIST OVER THE SAME LOCATION FOR AN HOUR OR
MORE, AN INCH OR TWO COULD ACCUMULATE.

AFTER A SHORT BREAK IN PRECIPITATION THIS AFTERNOON AND EARLY
EVENING, NEXT TROUGH APPROACHES THE SIERRA TONIGHT. THIS SYSTEM
WILL INITIALLY HAVE A DECENT MOISTURE FEED AND FORCING, BUT WILL
ALSO WEAKEN AND ELONGATE AS IT REACHES THE SIERRA. THE MOST LIKELY
TIMING FOR A PERIOD OF STEADY SNOW WILL BE DURING THE LATE NIGHT
AND EARLY MORNING HOURS NEAR THE SIERRA. THIS WILL BE A SHORT
DURATION EVENT WHICH WILL KEEP SNOWFALL TOTALS BELOW ADVISORY
CRITERIA. SNOW AMOUNTS OF 1-4 INCHES ARE EXPECTED FROM WESTERN
LASSEN COUNTY ACROSS THE TAHOE BASIN AND INTO WESTERN MONO COUNTY,
WITH 3-6 INCHES NEAR THE SIERRA CREST. FOR EASTERN LASSEN AND INTO
FAR WESTERN NV, ACCUMULATIONS OF 1 INCH OR LESS ARE EXPECTED.
DESPITE THE LOW SNOW TOTALS, CHAIN CONTROLS WILL LIKELY BE IN
PLACE OVER MANY EASTERN SIERRA HIGHWAYS, WITH SLICK ROAD
CONDITIONS ALSO POSSIBLE IN LOWER ELEVATIONS AROUND RENO-CARSON
CITY AND SUSANVILLE THROUGH THE WEDNESDAY MORNING COMMUTE.

MOST OF THE SNOW WILL TAPER OFF TO SNOW SHOWERS DURING THE DAY
WEDNESDAY AS THE MAIN TROUGH MOVES EAST. HOWEVER, THERE MAY BE
SOME MORE PERSISTENT SNOW BANDS OVER PARTS OF NORTHEAST CA AS SOME
OF THE MODEL GUIDANCE (ESPECIALLY THE GFS) KEEPS A SMALL AREA OF
UPPER LEVEL FORCING IN PLACE. THIS COULD LEAD TO A FEW EXTRA
INCHES OF SNOW ACCUMULATING IN PARTS OF WESTERN LASSEN AND CENTRAL
PLUMAS COUNTIES.

FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT, SHORTWAVE RIDGE MOVING
ACROSS THE REGION WILL BRING ANY LEFTOVER SNOW SHOWERS TO AN END,
ALTHOUGH ANY BREAKS IN CLOUD COVER WILL BE SHORT LIVED. THE RIDGE
AXIS MOVES EAST ACROSS THE GREAT BASIN BY THURSDAY NIGHT WITH
WIDESPREAD CIRRUS SPREADING INTO THE REGION, AS ANOTHER TROUGH
APPROACHES THE WEST COAST. MJD

LONG TERM...FRIDAY THROUGH TUESDAY...

LOW PRESSURE OVER THE GULF OF ALASKA WILL DROP INTO THE PAC NW
FRIDAY, BRINGING ANOTHER CHANCE OF PRECIPITATION IN THE SIERRA AND
WESTERN NEVADA. THE TIMING OF THE FRONT HAS BEEN CONSISTENT OVER THE
LAST FEW DAYS, PUSHING THROUGH THE AREA ON FRIDAY. HOWEVER, THE
TRACK OF THE SHORTWAVE HAS BEEN CHANGING FROM RUN TO RUN, WHICH
LEADS TO LOWER CONFIDENCE IN THE OVERALL QPF/SNOW TOTALS FRIDAY
INTO SATURDAY. THE ECMWF THAT HAD BEEN SHOWING A SOLID QPF IN THE
SIERRA HAS NOW BACKED OFF WITH THE MOST RECENT 00Z RUN, LOOKING
MORE LIKE THE DRIER GFS. THIS IS UNFORTUNATE, BECAUSE NOW BOTH GFS
AND ECMWF ARE IN AGREEMENT THAT THE HEAVIEST PRECIP WILL REMAIN
NORTH IN WA/OR. SO EVEN THOUGH THIS STORM DOESN`T LOOK OVERLY
STRONG, IT MAY STILL CAUSE TRAVEL IMPACTS IN THE SIERRA FRIDAY
INTO SATURDAY MORNING.

BY SUNDAY, A RIDGE OF HIGH PRESSURE LOOKS TO BUILD OVER CA/NV WITH
LIGHT WAA CLOUDS/PRECIP ON SUNDAY AND MONDAY NEAR THE OREGON BORDER.
FOR THE REST OF THE FORECAST AREA, HIGH PRESSURE WILL MEAN LESS
CLOUDS, COOL AND DRY CONDITIONS, LIGHT WINDS, VALLEY INVERSIONS AND
POSSIBLE AIR QUALITY ISSUES EARLY NEXT WEEK. HOON

AVIATION...

LIGHT SNOW SHOWERS WILL CONTINUE IN THE SIERRA THIS MORNING WITH
PERIODS OF MVFR CIG/VIS AT KTRK/KTVL/KMMH. ADDITIONAL SNOW
ACCUMULATIONS THIS MORNING WILL BE MINIMAL, LESS THAN AN INCH.

BY TONIGHT, ANOTHER WAVE MOVES THROUGH THE SIERRA WITH 2-4" OF SNOW
POSSIBLE AT KTRK/KTVL/KMMH BY WEDNESDAY MORNING.

FOR KRNO/KCXP...A FEW SHOWERS AROUND THIS MORNING AND AGAIN TONIGHT,
BUT NO MAJOR RESTRICTIONS EXPECTED TO CIG/VIS. PERIODS OF MOUNTAIN
OBSCURATION AND LIGHT TURBULENCE/ICING EXPECTED THROUGH TONIGHT
AND INTO WEDNESDAY MORNING. HOON

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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








000
FXUS65 KREV 161759
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
959 AM PST TUE DEC 16 2014

.UPDATE...
UPDATED THROUGH THIS EVENING, MAINLY TO LOWER SKY COVER IN THE
BASIN SOUTH OF GERLACH AND TO REMOVE AFTERNOON SHOWERS OUTSIDE OF
EASTERN CALIFORNIA. THE UPPER IMPULSE THAT AFFECTED THE REGION
LAST NIGHT HAS MOVED INTO NEVADA RESULTING IN A WEAKENING OR
DISSIPATION OF SHOWERS FOR MOST AREAS EAST OF THE SIERRA CREST.

THE NEXT DISTURBANCE DUE IN LATE TONIGHT CONTINUES TO LOOK WEAK
AND ELONGATED ALTHOUGH TRAVEL ISSUES (CHAIN REQUIREMENTS) ARE
STILL LIKELY IN THE SIERRA AND FOR PORTIONS OF LASSEN AND EASTERN
PLUMAS COUNTIES LATE TONIGHT AND WEDNESDAY MORNING WITH THE
EXPECTED, BUT RELATIVELY LIGHT, SNOWFALL. SNYDER

&&

.SYNOPSIS...
A SERIES OF WEAK WEATHER SYSTEMS WILL BRING PERIODS OF SNOW TO THE
SIERRA AND WESTERN NEVADA THIS WEEK. ALTHOUGH HEAVY SNOW IS NOT
EXPECTED, SLICK DRIVING CONDITIONS WILL LIKELY IMPACT THE PEAK
MORNING AND EVENING COMMUTE TIMES THROUGH WEDNESDAY. ANOTHER ROUND
OF LIGHT SNOW AND RAIN IS POSSIBLE FRIDAY AND FRIDAY NIGHT.

&&

.PREVIOUS DISCUSSION... /ISSUED 411 AM PST TUE DEC 16 2014/

SHORT TERM...

AREAS OF LIGHT SNOW OVERNIGHT HAVE PRODUCED SLICK AND ICY
CONDITIONS OVER MANY SIERRA HIGHWAYS, WITH WIDESPREAD CHAIN CONTROLS
IN PLACE AS OF EARLY THIS MORNING. A NARROW BAND OF LAKE EFFECT SNOW
SHOWERS ORIGINATING FROM TAHOE HAS ALSO PRODUCED SLICK CONDITIONS
AND CHAIN RESTRICTIONS ON I-580 AND BOWERS MANSION ROAD BETWEEN RENO
AND CARSON CITY. SLOW DOWN AND USE EXTRA CAUTION AS SLICK ROADS WILL
PERSIST FOR THE MORNING COMMUTE.

WEAK VORTICITY CENTER MOVING ACROSS THE CENTRAL SIERRA WILL KEEP
BANDS OF SNOW SHOWERS GOING UNTIL AROUND DAYBREAK. WHILE MOST OF
THE SHOWERS WILL REMAIN NEAR THE SIERRA CREST, SCATTERED BRIEF SNOW
SHOWERS WILL MAKE THEIR WAY INTO LOWER ELEVATIONS OF WESTERN NV
AND NORTHEAST CA. MOST ACTIVITY WILL DIMINISH LATER THIS MORNING
AS DYNAMICS WEAKEN AFTER THIS SYSTEM MOVES EAST OF THE REGION.
SNOW ACCUMULATIONS WILL BE MORE LOCALIZED COMPARED TO YESTERDAY.
IF A BAND IS ABLE TO PERSIST OVER THE SAME LOCATION FOR AN HOUR OR
MORE, AN INCH OR TWO COULD ACCUMULATE.

AFTER A SHORT BREAK IN PRECIPITATION THIS AFTERNOON AND EARLY
EVENING, NEXT TROUGH APPROACHES THE SIERRA TONIGHT. THIS SYSTEM
WILL INITIALLY HAVE A DECENT MOISTURE FEED AND FORCING, BUT WILL
ALSO WEAKEN AND ELONGATE AS IT REACHES THE SIERRA. THE MOST LIKELY
TIMING FOR A PERIOD OF STEADY SNOW WILL BE DURING THE LATE NIGHT
AND EARLY MORNING HOURS NEAR THE SIERRA. THIS WILL BE A SHORT
DURATION EVENT WHICH WILL KEEP SNOWFALL TOTALS BELOW ADVISORY
CRITERIA. SNOW AMOUNTS OF 1-4 INCHES ARE EXPECTED FROM WESTERN
LASSEN COUNTY ACROSS THE TAHOE BASIN AND INTO WESTERN MONO COUNTY,
WITH 3-6 INCHES NEAR THE SIERRA CREST. FOR EASTERN LASSEN AND INTO
FAR WESTERN NV, ACCUMULATIONS OF 1 INCH OR LESS ARE EXPECTED.
DESPITE THE LOW SNOW TOTALS, CHAIN CONTROLS WILL LIKELY BE IN
PLACE OVER MANY EASTERN SIERRA HIGHWAYS, WITH SLICK ROAD
CONDITIONS ALSO POSSIBLE IN LOWER ELEVATIONS AROUND RENO-CARSON
CITY AND SUSANVILLE THROUGH THE WEDNESDAY MORNING COMMUTE.

MOST OF THE SNOW WILL TAPER OFF TO SNOW SHOWERS DURING THE DAY
WEDNESDAY AS THE MAIN TROUGH MOVES EAST. HOWEVER, THERE MAY BE
SOME MORE PERSISTENT SNOW BANDS OVER PARTS OF NORTHEAST CA AS SOME
OF THE MODEL GUIDANCE (ESPECIALLY THE GFS) KEEPS A SMALL AREA OF
UPPER LEVEL FORCING IN PLACE. THIS COULD LEAD TO A FEW EXTRA
INCHES OF SNOW ACCUMULATING IN PARTS OF WESTERN LASSEN AND CENTRAL
PLUMAS COUNTIES.

FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT, SHORTWAVE RIDGE MOVING
ACROSS THE REGION WILL BRING ANY LEFTOVER SNOW SHOWERS TO AN END,
ALTHOUGH ANY BREAKS IN CLOUD COVER WILL BE SHORT LIVED. THE RIDGE
AXIS MOVES EAST ACROSS THE GREAT BASIN BY THURSDAY NIGHT WITH
WIDESPREAD CIRRUS SPREADING INTO THE REGION, AS ANOTHER TROUGH
APPROACHES THE WEST COAST. MJD

LONG TERM...FRIDAY THROUGH TUESDAY...

LOW PRESSURE OVER THE GULF OF ALASKA WILL DROP INTO THE PAC NW
FRIDAY, BRINGING ANOTHER CHANCE OF PRECIPITATION IN THE SIERRA AND
WESTERN NEVADA. THE TIMING OF THE FRONT HAS BEEN CONSISTENT OVER THE
LAST FEW DAYS, PUSHING THROUGH THE AREA ON FRIDAY. HOWEVER, THE
TRACK OF THE SHORTWAVE HAS BEEN CHANGING FROM RUN TO RUN, WHICH
LEADS TO LOWER CONFIDENCE IN THE OVERALL QPF/SNOW TOTALS FRIDAY
INTO SATURDAY. THE ECMWF THAT HAD BEEN SHOWING A SOLID QPF IN THE
SIERRA HAS NOW BACKED OFF WITH THE MOST RECENT 00Z RUN, LOOKING
MORE LIKE THE DRIER GFS. THIS IS UNFORTUNATE, BECAUSE NOW BOTH GFS
AND ECMWF ARE IN AGREEMENT THAT THE HEAVIEST PRECIP WILL REMAIN
NORTH IN WA/OR. SO EVEN THOUGH THIS STORM DOESN`T LOOK OVERLY
STRONG, IT MAY STILL CAUSE TRAVEL IMPACTS IN THE SIERRA FRIDAY
INTO SATURDAY MORNING.

BY SUNDAY, A RIDGE OF HIGH PRESSURE LOOKS TO BUILD OVER CA/NV WITH
LIGHT WAA CLOUDS/PRECIP ON SUNDAY AND MONDAY NEAR THE OREGON BORDER.
FOR THE REST OF THE FORECAST AREA, HIGH PRESSURE WILL MEAN LESS
CLOUDS, COOL AND DRY CONDITIONS, LIGHT WINDS, VALLEY INVERSIONS AND
POSSIBLE AIR QUALITY ISSUES EARLY NEXT WEEK. HOON

AVIATION...

LIGHT SNOW SHOWERS WILL CONTINUE IN THE SIERRA THIS MORNING WITH
PERIODS OF MVFR CIG/VIS AT KTRK/KTVL/KMMH. ADDITIONAL SNOW
ACCUMULATIONS THIS MORNING WILL BE MINIMAL, LESS THAN AN INCH.

BY TONIGHT, ANOTHER WAVE MOVES THROUGH THE SIERRA WITH 2-4" OF SNOW
POSSIBLE AT KTRK/KTVL/KMMH BY WEDNESDAY MORNING.

FOR KRNO/KCXP...A FEW SHOWERS AROUND THIS MORNING AND AGAIN TONIGHT,
BUT NO MAJOR RESTRICTIONS EXPECTED TO CIG/VIS. PERIODS OF MOUNTAIN
OBSCURATION AND LIGHT TURBULENCE/ICING EXPECTED THROUGH TONIGHT
AND INTO WEDNESDAY MORNING. HOON

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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







000
FXUS65 KREV 161237 CCB
AFDREV

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE RENO NV
411 AM PST TUE DEC 16 2014

.SYNOPSIS...

A SERIES OF WEAK WEATHER SYSTEMS WILL BRING PERIODS OF SNOW TO
THE SIERRA AND WESTERN NEVADA THIS WEEK. ALTHOUGH HEAVY SNOW IS
NOT EXPECTED, SLICK DRIVING CONDITIONS WILL LIKELY IMPACT THE PEAK
MORNING AND EVENING COMMUTE TIMES THROUGH WEDNESDAY. ANOTHER ROUND
OF LIGHT SNOW AND RAIN IS POSSIBLE FRIDAY AND FRIDAY NIGHT.

&&

.SHORT TERM...

AREAS OF LIGHT SNOW OVERNIGHT HAVE PRODUCED SLICK AND ICY
CONDITIONS OVER MANY SIERRA HIGHWAYS, WITH WIDESPREAD CHAIN CONTROLS
IN PLACE AS OF EARLY THIS MORNING. A NARROW BAND OF LAKE EFFECT SNOW
SHOWERS ORIGINATING FROM TAHOE HAS ALSO PRODUCED SLICK CONDITIONS
AND CHAIN RESTRICTIONS ON I-580 AND BOWERS MANSION ROAD BETWEEN RENO
AND CARSON CITY. SLOW DOWN AND USE EXTRA CAUTION AS SLICK ROADS WILL
PERSIST FOR THE MORNING COMMUTE.

WEAK VORTICITY CENTER MOVING ACROSS THE CENTRAL SIERRA WILL KEEP
BANDS OF SNOW SHOWERS GOING UNTIL AROUND DAYBREAK. WHILE MOST OF
THE SHOWERS WILL REMAIN NEAR THE SIERRA CREST, SCATTERED BRIEF SNOW
SHOWERS WILL MAKE THEIR WAY INTO LOWER ELEVATIONS OF WESTERN NV
AND NORTHEAST CA. MOST ACTIVITY WILL DIMINISH LATER THIS MORNING
AS DYNAMICS WEAKEN AFTER THIS SYSTEM MOVES EAST OF THE REGION.
SNOW ACCUMULATIONS WILL BE MORE LOCALIZED COMPARED TO YESTERDAY.
IF A BAND IS ABLE TO PERSIST OVER THE SAME LOCATION FOR AN HOUR OR
MORE, AN INCH OR TWO COULD ACCUMULATE.

AFTER A SHORT BREAK IN PRECIPITATION THIS AFTERNOON AND EARLY
EVENING, NEXT TROUGH APPROACHES THE SIERRA TONIGHT. THIS SYSTEM
WILL INITIALLY HAVE A DECENT MOISTURE FEED AND FORCING, BUT WILL
ALSO WEAKEN AND ELONGATE AS IT REACHES THE SIERRA. THE MOST LIKELY
TIMING FOR A PERIOD OF STEADY SNOW WILL BE DURING THE LATE NIGHT
AND EARLY MORNING HOURS NEAR THE SIERRA. THIS WILL BE A SHORT
DURATION EVENT WHICH WILL KEEP SNOWFALL TOTALS BELOW ADVISORY
CRITERIA. SNOW AMOUNTS OF 1-4 INCHES ARE EXPECTED FROM WESTERN
LASSEN COUNTY ACROSS THE TAHOE BASIN AND INTO WESTERN MONO COUNTY,
WITH 3-6 INCHES NEAR THE SIERRA CREST. FOR EASTERN LASSEN AND INTO
FAR WESTERN NV, ACCUMULATIONS OF 1 INCH OR LESS ARE EXPECTED.
DESPITE THE LOW SNOW TOTALS, CHAIN CONTROLS WILL LIKELY BE IN
PLACE OVER MANY EASTERN SIERRA HIGHWAYS, WITH SLICK ROAD
CONDITIONS ALSO POSSIBLE IN LOWER ELEVATIONS AROUND RENO-CARSON
CITY AND SUSANVILLE THROUGH THE WEDNESDAY MORNING COMMUTE.

MOST OF THE SNOW WILL TAPER OFF TO SNOW SHOWERS DURING THE DAY
WEDNESDAY AS THE MAIN TROUGH MOVES EAST. HOWEVER, THERE MAY BE
SOME MORE PERSISTENT SNOW BANDS OVER PARTS OF NORTHEAST CA AS SOME
OF THE MODEL GUIDANCE (ESPECIALLY THE GFS) KEEPS A SMALL AREA OF
UPPER LEVEL FORCING IN PLACE. THIS COULD LEAD TO A FEW EXTRA
INCHES OF SNOW ACCUMULATING IN PARTS OF WESTERN LASSEN AND CENTRAL
PLUMAS COUNTIES.

FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT, SHORTWAVE RIDGE MOVING
ACROSS THE REGION WILL BRING ANY LEFTOVER SNOW SHOWERS TO AN END,
ALTHOUGH ANY BREAKS IN CLOUD COVER WILL BE SHORT LIVED. THE RIDGE
AXIS MOVES EAST ACROSS THE GREAT BASIN BY THURSDAY NIGHT WITH
WIDESPREAD CIRRUS SPREADING INTO THE REGION, AS ANOTHER TROUGH
APPROACHES THE WEST COAST. MJD

.LONG TERM...FRIDAY THROUGH TUESDAY...

LOW PRESSURE OVER THE GULF OF ALASKA WILL DROP INTO THE PAC NW
FRIDAY, BRINGING ANOTHER CHANCE OF PRECIPITATION IN THE SIERRA AND
WESTERN NEVADA. THE TIMING OF THE FRONT HAS BEEN CONSISTENT OVER THE
LAST FEW DAYS, PUSHING THROUGH THE AREA ON FRIDAY. HOWEVER, THE
TRACK OF THE SHORTWAVE HAS BEEN CHANGING FROM RUN TO RUN, WHICH
LEADS TO LOWER CONFIDENCE IN THE OVERALL QPF/SNOW TOTALS FRIDAY
INTO SATURDAY. THE ECMWF THAT HAD BEEN SHOWING A SOLID QPF IN THE
SIERRA HAS NOW BACKED OFF WITH THE MOST RECENT 00Z RUN, LOOKING
MORE LIKE THE DRIER GFS. THIS IS UNFORTUNATE, BECAUSE NOW BOTH GFS
AND ECMWF ARE IN AGREEMENT THAT THE HEAVIEST PRECIP WILL REMAIN
NORTH IN WA/OR. SO EVEN THOUGH THIS STORM DOESN`T LOOK OVERLY
STRONG, IT MAY STILL CAUSE TRAVEL IMPACTS IN THE SIERRA FRIDAY
INTO SATURDAY MORNING.

BY SUNDAY, A RIDGE OF HIGH PRESSURE LOOKS TO BUILD OVER CA/NV WITH
LIGHT WAA CLOUDS/PRECIP ON SUNDAY AND MONDAY NEAR THE OREGON BORDER.
FOR THE REST OF THE FORECAST AREA, HIGH PRESSURE WILL MEAN LESS
CLOUDS, COOL AND DRY CONDITIONS, LIGHT WINDS, VALLEY INVERSIONS AND
POSSIBLE AIR QUALITY ISSUES EARLY NEXT WEEK. HOON

&&

.AVIATION...

LIGHT SNOW SHOWERS WILL CONTINUE IN THE SIERRA THIS MORNING WITH
PERIODS OF MVFR CIG/VIS AT KTRK/KTVL/KMMH. ADDITIONAL SNOW
ACCUMULATIONS THIS MORNING WILL BE MINIMAL, LESS THAN AN INCH.

BY TONIGHT, ANOTHER WAVE MOVES THROUGH THE SIERRA WITH 2-4" OF SNOW
POSSIBLE AT KTRK/KTVL/KMMH BY WEDNESDAY MORNING.

FOR KRNO/KCXP...A FEW SHOWERS AROUND THIS MORNING AND AGAIN TONIGHT,
BUT NO MAJOR RESTRICTIONS EXPECTED TO CIG/VIS. PERIODS OF MOUNTAIN
OBSCURATION AND LIGHT TURBULENCE/ICING EXPECTED THROUGH TONIGHT
AND INTO WEDNESDAY MORNING. HOON

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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














000
FXUS65 KREV 161237 CCB
AFDREV

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE RENO NV
411 AM PST TUE DEC 16 2014

.SYNOPSIS...

A SERIES OF WEAK WEATHER SYSTEMS WILL BRING PERIODS OF SNOW TO
THE SIERRA AND WESTERN NEVADA THIS WEEK. ALTHOUGH HEAVY SNOW IS
NOT EXPECTED, SLICK DRIVING CONDITIONS WILL LIKELY IMPACT THE PEAK
MORNING AND EVENING COMMUTE TIMES THROUGH WEDNESDAY. ANOTHER ROUND
OF LIGHT SNOW AND RAIN IS POSSIBLE FRIDAY AND FRIDAY NIGHT.

&&

.SHORT TERM...

AREAS OF LIGHT SNOW OVERNIGHT HAVE PRODUCED SLICK AND ICY
CONDITIONS OVER MANY SIERRA HIGHWAYS, WITH WIDESPREAD CHAIN CONTROLS
IN PLACE AS OF EARLY THIS MORNING. A NARROW BAND OF LAKE EFFECT SNOW
SHOWERS ORIGINATING FROM TAHOE HAS ALSO PRODUCED SLICK CONDITIONS
AND CHAIN RESTRICTIONS ON I-580 AND BOWERS MANSION ROAD BETWEEN RENO
AND CARSON CITY. SLOW DOWN AND USE EXTRA CAUTION AS SLICK ROADS WILL
PERSIST FOR THE MORNING COMMUTE.

WEAK VORTICITY CENTER MOVING ACROSS THE CENTRAL SIERRA WILL KEEP
BANDS OF SNOW SHOWERS GOING UNTIL AROUND DAYBREAK. WHILE MOST OF
THE SHOWERS WILL REMAIN NEAR THE SIERRA CREST, SCATTERED BRIEF SNOW
SHOWERS WILL MAKE THEIR WAY INTO LOWER ELEVATIONS OF WESTERN NV
AND NORTHEAST CA. MOST ACTIVITY WILL DIMINISH LATER THIS MORNING
AS DYNAMICS WEAKEN AFTER THIS SYSTEM MOVES EAST OF THE REGION.
SNOW ACCUMULATIONS WILL BE MORE LOCALIZED COMPARED TO YESTERDAY.
IF A BAND IS ABLE TO PERSIST OVER THE SAME LOCATION FOR AN HOUR OR
MORE, AN INCH OR TWO COULD ACCUMULATE.

AFTER A SHORT BREAK IN PRECIPITATION THIS AFTERNOON AND EARLY
EVENING, NEXT TROUGH APPROACHES THE SIERRA TONIGHT. THIS SYSTEM
WILL INITIALLY HAVE A DECENT MOISTURE FEED AND FORCING, BUT WILL
ALSO WEAKEN AND ELONGATE AS IT REACHES THE SIERRA. THE MOST LIKELY
TIMING FOR A PERIOD OF STEADY SNOW WILL BE DURING THE LATE NIGHT
AND EARLY MORNING HOURS NEAR THE SIERRA. THIS WILL BE A SHORT
DURATION EVENT WHICH WILL KEEP SNOWFALL TOTALS BELOW ADVISORY
CRITERIA. SNOW AMOUNTS OF 1-4 INCHES ARE EXPECTED FROM WESTERN
LASSEN COUNTY ACROSS THE TAHOE BASIN AND INTO WESTERN MONO COUNTY,
WITH 3-6 INCHES NEAR THE SIERRA CREST. FOR EASTERN LASSEN AND INTO
FAR WESTERN NV, ACCUMULATIONS OF 1 INCH OR LESS ARE EXPECTED.
DESPITE THE LOW SNOW TOTALS, CHAIN CONTROLS WILL LIKELY BE IN
PLACE OVER MANY EASTERN SIERRA HIGHWAYS, WITH SLICK ROAD
CONDITIONS ALSO POSSIBLE IN LOWER ELEVATIONS AROUND RENO-CARSON
CITY AND SUSANVILLE THROUGH THE WEDNESDAY MORNING COMMUTE.

MOST OF THE SNOW WILL TAPER OFF TO SNOW SHOWERS DURING THE DAY
WEDNESDAY AS THE MAIN TROUGH MOVES EAST. HOWEVER, THERE MAY BE
SOME MORE PERSISTENT SNOW BANDS OVER PARTS OF NORTHEAST CA AS SOME
OF THE MODEL GUIDANCE (ESPECIALLY THE GFS) KEEPS A SMALL AREA OF
UPPER LEVEL FORCING IN PLACE. THIS COULD LEAD TO A FEW EXTRA
INCHES OF SNOW ACCUMULATING IN PARTS OF WESTERN LASSEN AND CENTRAL
PLUMAS COUNTIES.

FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT, SHORTWAVE RIDGE MOVING
ACROSS THE REGION WILL BRING ANY LEFTOVER SNOW SHOWERS TO AN END,
ALTHOUGH ANY BREAKS IN CLOUD COVER WILL BE SHORT LIVED. THE RIDGE
AXIS MOVES EAST ACROSS THE GREAT BASIN BY THURSDAY NIGHT WITH
WIDESPREAD CIRRUS SPREADING INTO THE REGION, AS ANOTHER TROUGH
APPROACHES THE WEST COAST. MJD

.LONG TERM...FRIDAY THROUGH TUESDAY...

LOW PRESSURE OVER THE GULF OF ALASKA WILL DROP INTO THE PAC NW
FRIDAY, BRINGING ANOTHER CHANCE OF PRECIPITATION IN THE SIERRA AND
WESTERN NEVADA. THE TIMING OF THE FRONT HAS BEEN CONSISTENT OVER THE
LAST FEW DAYS, PUSHING THROUGH THE AREA ON FRIDAY. HOWEVER, THE
TRACK OF THE SHORTWAVE HAS BEEN CHANGING FROM RUN TO RUN, WHICH
LEADS TO LOWER CONFIDENCE IN THE OVERALL QPF/SNOW TOTALS FRIDAY
INTO SATURDAY. THE ECMWF THAT HAD BEEN SHOWING A SOLID QPF IN THE
SIERRA HAS NOW BACKED OFF WITH THE MOST RECENT 00Z RUN, LOOKING
MORE LIKE THE DRIER GFS. THIS IS UNFORTUNATE, BECAUSE NOW BOTH GFS
AND ECMWF ARE IN AGREEMENT THAT THE HEAVIEST PRECIP WILL REMAIN
NORTH IN WA/OR. SO EVEN THOUGH THIS STORM DOESN`T LOOK OVERLY
STRONG, IT MAY STILL CAUSE TRAVEL IMPACTS IN THE SIERRA FRIDAY
INTO SATURDAY MORNING.

BY SUNDAY, A RIDGE OF HIGH PRESSURE LOOKS TO BUILD OVER CA/NV WITH
LIGHT WAA CLOUDS/PRECIP ON SUNDAY AND MONDAY NEAR THE OREGON BORDER.
FOR THE REST OF THE FORECAST AREA, HIGH PRESSURE WILL MEAN LESS
CLOUDS, COOL AND DRY CONDITIONS, LIGHT WINDS, VALLEY INVERSIONS AND
POSSIBLE AIR QUALITY ISSUES EARLY NEXT WEEK. HOON

&&

.AVIATION...

LIGHT SNOW SHOWERS WILL CONTINUE IN THE SIERRA THIS MORNING WITH
PERIODS OF MVFR CIG/VIS AT KTRK/KTVL/KMMH. ADDITIONAL SNOW
ACCUMULATIONS THIS MORNING WILL BE MINIMAL, LESS THAN AN INCH.

BY TONIGHT, ANOTHER WAVE MOVES THROUGH THE SIERRA WITH 2-4" OF SNOW
POSSIBLE AT KTRK/KTVL/KMMH BY WEDNESDAY MORNING.

FOR KRNO/KCXP...A FEW SHOWERS AROUND THIS MORNING AND AGAIN TONIGHT,
BUT NO MAJOR RESTRICTIONS EXPECTED TO CIG/VIS. PERIODS OF MOUNTAIN
OBSCURATION AND LIGHT TURBULENCE/ICING EXPECTED THROUGH TONIGHT
AND INTO WEDNESDAY MORNING. HOON

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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















000
FXUS65 KREV 161223 CCA
AFDREV

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE RENO NV
411 AM PST TUE DEC 16 2014

.SYNOPSIS...

A SERIES OF WEAK WEATHER SYSTEMS WILL BRING PERIODS OF SNOW TO
THE SIERRA AND WESTERN NEVADA THIS WEEK. ALTHOUGH HEAVY SNOW IS
NOT EXPECTED, SLICK DRIVING CONDITIONS WILL LIKELY IMPACT THE PEAK
MORNING AND EVENING COMMUTE TIMES THROUGH WEDNESDAY. ANOTHER ROUND
OF LIGHT SNOW AND RAIN IS POSSIBLE FRIDAY AND FRIDAY NIGHT.

&&

.SHORT TERM...

AREAS OF LIGHT SNOW OVERNIGHT HAVE PRODUCED SLICK AND ICY
CONDITIONS OVER MANY SIERRA HIGHWAYS, WITH WIDESPREAD CHAIN
CONTROLS IN PLACE AS OF EARLY THIS MORNING. A NARROW BAND OF SNOW
SHOWERS ORIGINATING FROM LAKE TAHOE HAS ALSO PRODUCED SLICK
CONDITIONS AND CHAIN RESTRICTIONS ON I-580 AND OLD US 395 BETWEEN
RENO AND CARSON CITY. SLOW DOWN AND USE EXTRA CAUTION AS SLICK
ROADS WILL PERSIST FOR THE MORNING COMMUTE.

WEAK VORTICITY CENTER MOVING ACROSS THE CENTRAL SIERRA WILL KEEP
BANDS OF SNOW SHOWERS GOING UNTIL AROUND DAYBREAK. WHILE MOST OF
THE SHOWERS WILL REMAIN NEAR THE SIERRA CREST, SCATTERED BRIEF SNOW
SHOWERS WILL MAKE THEIR WAY INTO LOWER ELEVATIONS OF WESTERN NV
AND NORTHEAST CA. MOST ACTIVITY WILL DIMINISH LATER THIS MORNING
AS DYNAMICS WEAKEN AFTER THIS SYSTEM MOVES EAST OF THE REGION.
SNOW ACCUMULATIONS WILL BE MORE LOCALIZED COMPARED TO YESTERDAY.
IF A BAND IS ABLE TO PERSIST OVER THE SAME LOCATION FOR AN HOUR OR
MORE, AN INCH OR TWO COULD ACCUMULATE.

AFTER A SHORT BREAK IN PRECIPITATION THIS AFTERNOON AND EARLY
EVENING, NEXT TROUGH APPROACHES THE SIERRA TONIGHT. THIS SYSTEM
WILL INITIALLY HAVE A DECENT MOISTURE FEED AND FORCING, BUT WILL
ALSO WEAKEN AND ELONGATE AS IT REACHES THE SIERRA. THE MOST LIKELY
TIMING FOR A PERIOD OF STEADY SNOW WILL BE DURING THE LATE NIGHT
AND EARLY MORNING HOURS NEAR THE SIERRA. THIS WILL BE A SHORT
DURATION EVENT WHICH WILL KEEP SNOWFALL TOTALS BELOW ADVISORY
CRITERIA. SNOW AMOUNTS OF 1-4 INCHES ARE EXPECTED FROM WESTERN
LASSEN COUNTY ACROSS THE TAHOE BASIN AND INTO WESTERN MONO COUNTY,
WITH 3-6 INCHES NEAR THE SIERRA CREST. FOR EASTERN LASSEN AND INTO
FAR WESTERN NV, ACCUMULATIONS OF 1 INCH OR LESS ARE EXPECTED.
DESPITE THE LOW SNOW TOTALS, CHAIN CONTROLS WILL LIKELY BE IN
PLACE OVER MANY EASTERN SIERRA HIGHWAYS, WITH SLICK ROAD
CONDITIONS ALSO POSSIBLE IN LOWER ELEVATIONS AROUND RENO-CARSON
CITY AND SUSANVILLE THROUGH THE WEDNESDAY MORNING COMMUTE.

MOST OF THE SNOW WILL TAPER OFF TO SNOW SHOWERS DURING THE DAY
WEDNESDAY AS THE MAIN TROUGH MOVES EAST. HOWEVER, THERE MAY BE
SOME MORE PERSISTENT SNOW BANDS OVER PARTS OF NORTHEAST CA AS SOME
OF THE MODEL GUIDANCE (ESPECIALLY THE GFS) KEEPS A SMALL AREA OF
UPPER LEVEL FORCING IN PLACE. THIS COULD LEAD TO A FEW EXTRA
INCHES OF SNOW ACCUMULATING IN PARTS OF WESTERN LASSEN AND CENTRAL
PLUMAS COUNTIES.

FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT, SHORTWAVE RIDGE MOVING
ACROSS THE REGION WILL BRING ANY LEFTOVER SNOW SHOWERS TO AN END,
ALTHOUGH ANY BREAKS IN CLOUD COVER WILL BE SHORT LIVED. THE RIDGE
AXIS MOVES EAST ACROSS THE GREAT BASIN BY THURSDAY NIGHT WITH
WIDESPREAD CIRRUS SPREADING INTO THE REGION, AS ANOTHER TROUGH
APPROACHES THE WEST COAST. MJD

.LONG TERM...FRIDAY THROUGH TUESDAY...

LOW PRESSURE OVER THE GULF OF ALASKA WILL DROP INTO THE PAC NW
FRIDAY, BRINGING ANOTHER CHANCE OF PRECIPITATION IN THE SIERRA AND
WESTERN NEVADA. THE TIMING OF THE FRONT HAS BEEN CONSISTENT OVER THE
LAST FEW DAYS, PUSHING THROUGH THE AREA ON FRIDAY. HOWEVER, THE
TRACK OF THE SHORTWAVE HAS BEEN CHANGING FROM RUN TO RUN, WHICH
LEADS TO LOWER CONFIDENCE IN THE OVERALL QPF/SNOW TOTALS FRIDAY
INTO SATURDAY. THE ECMWF THAT HAD BEEN SHOWING A SOLID QPF IN THE
SIERRA HAS NOW BACKED OFF WITH THE MOST RECENT 00Z RUN, LOOKING
MORE LIKE THE DRIER GFS. THIS IS UNFORTUNATE, BECAUSE NOW BOTH GFS
AND ECMWF ARE IN AGREEMENT THAT THE HEAVIEST PRECIP WILL REMAIN
NORTH IN WA/OR. SO EVEN THOUGH THIS STORM DOESN`T LOOK OVERLY
STRONG, IT MAY STILL CAUSE TRAVEL IMPACTS IN THE SIERRA FRIDAY
INTO SATURDAY MORNING.

BY SUNDAY, A RIDGE OF HIGH PRESSURE LOOKS TO BUILD OVER CA/NV WITH
LIGHT WAA CLOUDS/PRECIP ON SUNDAY AND MONDAY NEAR THE OREGON BORDER.
FOR THE REST OF THE FORECAST AREA, HIGH PRESSURE WILL MEAN LESS
CLOUDS, COOL AND DRY CONDITIONS, LIGHT WINDS, VALLEY INVERSIONS AND
POSSIBLE AIR QUALITY ISSUES EARLY NEXT WEEK. HOON

&&

.AVIATION...

LIGHT SNOW SHOWERS WILL CONTINUE IN THE SIERRA THIS MORNING WITH
PERIODS OF MVFR CIG/VIS AT KTRK/KTVL/KMMH. ADDITIONAL SNOW
ACCUMULATIONS THIS MORNING WILL BE MINIMAL, LESS THAN AN INCH.

BY TONIGHT, ANOTHER WAVE MOVES THROUGH THE SIERRA WITH 2-4" OF SNOW
POSSIBLE AT KTRK/KTVL/KMMH BY WEDNESDAY MORNING.

FOR KRNO/KCXP...A FEW SHOWERS AROUND THIS MORNING AND AGAIN TONIGHT,
BUT NO MAJOR RESTRICTIONS EXPECTED TO CIG/VIS. PERIODS OF MOUNTAIN
OBSCURATION AND LIGHT TURBULENCE/ICING EXPECTED THROUGH TONIGHT
AND INTO WEDNESDAY MORNING. HOON

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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












000
FXUS65 KREV 161223 CCA
AFDREV

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE RENO NV
411 AM PST TUE DEC 16 2014

.SYNOPSIS...

A SERIES OF WEAK WEATHER SYSTEMS WILL BRING PERIODS OF SNOW TO
THE SIERRA AND WESTERN NEVADA THIS WEEK. ALTHOUGH HEAVY SNOW IS
NOT EXPECTED, SLICK DRIVING CONDITIONS WILL LIKELY IMPACT THE PEAK
MORNING AND EVENING COMMUTE TIMES THROUGH WEDNESDAY. ANOTHER ROUND
OF LIGHT SNOW AND RAIN IS POSSIBLE FRIDAY AND FRIDAY NIGHT.

&&

.SHORT TERM...

AREAS OF LIGHT SNOW OVERNIGHT HAVE PRODUCED SLICK AND ICY
CONDITIONS OVER MANY SIERRA HIGHWAYS, WITH WIDESPREAD CHAIN
CONTROLS IN PLACE AS OF EARLY THIS MORNING. A NARROW BAND OF SNOW
SHOWERS ORIGINATING FROM LAKE TAHOE HAS ALSO PRODUCED SLICK
CONDITIONS AND CHAIN RESTRICTIONS ON I-580 AND OLD US 395 BETWEEN
RENO AND CARSON CITY. SLOW DOWN AND USE EXTRA CAUTION AS SLICK
ROADS WILL PERSIST FOR THE MORNING COMMUTE.

WEAK VORTICITY CENTER MOVING ACROSS THE CENTRAL SIERRA WILL KEEP
BANDS OF SNOW SHOWERS GOING UNTIL AROUND DAYBREAK. WHILE MOST OF
THE SHOWERS WILL REMAIN NEAR THE SIERRA CREST, SCATTERED BRIEF SNOW
SHOWERS WILL MAKE THEIR WAY INTO LOWER ELEVATIONS OF WESTERN NV
AND NORTHEAST CA. MOST ACTIVITY WILL DIMINISH LATER THIS MORNING
AS DYNAMICS WEAKEN AFTER THIS SYSTEM MOVES EAST OF THE REGION.
SNOW ACCUMULATIONS WILL BE MORE LOCALIZED COMPARED TO YESTERDAY.
IF A BAND IS ABLE TO PERSIST OVER THE SAME LOCATION FOR AN HOUR OR
MORE, AN INCH OR TWO COULD ACCUMULATE.

AFTER A SHORT BREAK IN PRECIPITATION THIS AFTERNOON AND EARLY
EVENING, NEXT TROUGH APPROACHES THE SIERRA TONIGHT. THIS SYSTEM
WILL INITIALLY HAVE A DECENT MOISTURE FEED AND FORCING, BUT WILL
ALSO WEAKEN AND ELONGATE AS IT REACHES THE SIERRA. THE MOST LIKELY
TIMING FOR A PERIOD OF STEADY SNOW WILL BE DURING THE LATE NIGHT
AND EARLY MORNING HOURS NEAR THE SIERRA. THIS WILL BE A SHORT
DURATION EVENT WHICH WILL KEEP SNOWFALL TOTALS BELOW ADVISORY
CRITERIA. SNOW AMOUNTS OF 1-4 INCHES ARE EXPECTED FROM WESTERN
LASSEN COUNTY ACROSS THE TAHOE BASIN AND INTO WESTERN MONO COUNTY,
WITH 3-6 INCHES NEAR THE SIERRA CREST. FOR EASTERN LASSEN AND INTO
FAR WESTERN NV, ACCUMULATIONS OF 1 INCH OR LESS ARE EXPECTED.
DESPITE THE LOW SNOW TOTALS, CHAIN CONTROLS WILL LIKELY BE IN
PLACE OVER MANY EASTERN SIERRA HIGHWAYS, WITH SLICK ROAD
CONDITIONS ALSO POSSIBLE IN LOWER ELEVATIONS AROUND RENO-CARSON
CITY AND SUSANVILLE THROUGH THE WEDNESDAY MORNING COMMUTE.

MOST OF THE SNOW WILL TAPER OFF TO SNOW SHOWERS DURING THE DAY
WEDNESDAY AS THE MAIN TROUGH MOVES EAST. HOWEVER, THERE MAY BE
SOME MORE PERSISTENT SNOW BANDS OVER PARTS OF NORTHEAST CA AS SOME
OF THE MODEL GUIDANCE (ESPECIALLY THE GFS) KEEPS A SMALL AREA OF
UPPER LEVEL FORCING IN PLACE. THIS COULD LEAD TO A FEW EXTRA
INCHES OF SNOW ACCUMULATING IN PARTS OF WESTERN LASSEN AND CENTRAL
PLUMAS COUNTIES.

FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT, SHORTWAVE RIDGE MOVING
ACROSS THE REGION WILL BRING ANY LEFTOVER SNOW SHOWERS TO AN END,
ALTHOUGH ANY BREAKS IN CLOUD COVER WILL BE SHORT LIVED. THE RIDGE
AXIS MOVES EAST ACROSS THE GREAT BASIN BY THURSDAY NIGHT WITH
WIDESPREAD CIRRUS SPREADING INTO THE REGION, AS ANOTHER TROUGH
APPROACHES THE WEST COAST. MJD

.LONG TERM...FRIDAY THROUGH TUESDAY...

LOW PRESSURE OVER THE GULF OF ALASKA WILL DROP INTO THE PAC NW
FRIDAY, BRINGING ANOTHER CHANCE OF PRECIPITATION IN THE SIERRA AND
WESTERN NEVADA. THE TIMING OF THE FRONT HAS BEEN CONSISTENT OVER THE
LAST FEW DAYS, PUSHING THROUGH THE AREA ON FRIDAY. HOWEVER, THE
TRACK OF THE SHORTWAVE HAS BEEN CHANGING FROM RUN TO RUN, WHICH
LEADS TO LOWER CONFIDENCE IN THE OVERALL QPF/SNOW TOTALS FRIDAY
INTO SATURDAY. THE ECMWF THAT HAD BEEN SHOWING A SOLID QPF IN THE
SIERRA HAS NOW BACKED OFF WITH THE MOST RECENT 00Z RUN, LOOKING
MORE LIKE THE DRIER GFS. THIS IS UNFORTUNATE, BECAUSE NOW BOTH GFS
AND ECMWF ARE IN AGREEMENT THAT THE HEAVIEST PRECIP WILL REMAIN
NORTH IN WA/OR. SO EVEN THOUGH THIS STORM DOESN`T LOOK OVERLY
STRONG, IT MAY STILL CAUSE TRAVEL IMPACTS IN THE SIERRA FRIDAY
INTO SATURDAY MORNING.

BY SUNDAY, A RIDGE OF HIGH PRESSURE LOOKS TO BUILD OVER CA/NV WITH
LIGHT WAA CLOUDS/PRECIP ON SUNDAY AND MONDAY NEAR THE OREGON BORDER.
FOR THE REST OF THE FORECAST AREA, HIGH PRESSURE WILL MEAN LESS
CLOUDS, COOL AND DRY CONDITIONS, LIGHT WINDS, VALLEY INVERSIONS AND
POSSIBLE AIR QUALITY ISSUES EARLY NEXT WEEK. HOON

&&

.AVIATION...

LIGHT SNOW SHOWERS WILL CONTINUE IN THE SIERRA THIS MORNING WITH
PERIODS OF MVFR CIG/VIS AT KTRK/KTVL/KMMH. ADDITIONAL SNOW
ACCUMULATIONS THIS MORNING WILL BE MINIMAL, LESS THAN AN INCH.

BY TONIGHT, ANOTHER WAVE MOVES THROUGH THE SIERRA WITH 2-4" OF SNOW
POSSIBLE AT KTRK/KTVL/KMMH BY WEDNESDAY MORNING.

FOR KRNO/KCXP...A FEW SHOWERS AROUND THIS MORNING AND AGAIN TONIGHT,
BUT NO MAJOR RESTRICTIONS EXPECTED TO CIG/VIS. PERIODS OF MOUNTAIN
OBSCURATION AND LIGHT TURBULENCE/ICING EXPECTED THROUGH TONIGHT
AND INTO WEDNESDAY MORNING. HOON

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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











000
FXUS65 KREV 161151
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
351 AM PST TUE DEC 16 2014

.SYNOPSIS...

A SERIES OF WEAK WEATHER SYSTEMS WILL BRING PERIODS OF SNOW TO
THE SIERRA AND WESTERN NEVADA THIS WEEK. ALTHOUGH HEAVY SNOW IS
NOT EXPECTED, SLICK DRIVING CONDITIONS COULD AFFECT LOWER
ELEVATIONS AND IMPACT THE PEAK MORNING AND EVENING COMMUTE TIMES
THROUGH WEDNESDAY. ANOTHER ROUND OF LIGHT SNOW AND RAIN IS
POSSIBLE FRIDAY AND FRIDAY NIGHT.

&&

.SHORT TERM...

WEAK VORTICITY CENTER MOVING ACROSS THE CENTRAL SIERRA WILL KEEP
BANDS OF SNOW SHOWERS GOING UNTIL AROUND DAYBREAK. WHILE MOST OF
THE SHOWERS WILL REMAIN NEAR THE SIERRA CREST, SCATTERED BRIEF SNOW
SHOWERS WILL MAKE THEIR WAY INTO LOWER ELEVATIONS OF WESTERN NV
AND NORTHEAST CA. MOST ACTIVITY WILL DIMINISH LATER THIS MORNING
AS DYNAMICS WEAKEN AFTER THIS SYSTEM MOVES EAST OF THE REGION.
SNOW ACCUMULATIONS WILL BE MORE LOCALIZED COMPARED TO YESTERDAY.
IF A BAND IS ABLE TO PERSIST OVER THE SAME LOCATION FOR AN HOUR OR
MORE, AN INCH OR TWO COULD ACCUMULATE.

AFTER A SHORT BREAK IN PRECIPITATION THIS AFTERNOON AND EARLY
EVENING, NEXT TROUGH APPROACHES THE SIERRA TONIGHT. THIS SYSTEM
WILL INITIALLY HAVE A DECENT MOISTURE FEED AND FORCING, BUT WILL
ALSO WEAKEN AND ELONGATE AS IT REACHES THE SIERRA. THE MOST LIKELY
TIMING FOR A PERIOD OF STEADY SNOW WILL BE DURING THE LATE NIGHT
AND EARLY MORNING HOURS NEAR THE SIERRA. THIS WILL BE A SHORT
DURATION EVENT WHICH WILL KEEP SNOWFALL TOTALS BELOW ADVISORY
CRITERIA. SNOW AMOUNTS OF 1-4 INCHES ARE EXPECTED FROM WESTERN
LASSEN COUNTY ACROSS THE TAHOE BASIN AND INTO WESTERN MONO COUNTY,
WITH 3-6 INCHES NEAR THE SIERRA CREST. FOR EASTERN LASSEN AND INTO
FAR WESTERN NV, ACCUMULATIONS OF 1 INCH OR LESS ARE EXPECTED.
DESPITE THE LOW SNOW TOTALS, CHAIN CONTROLS WILL LIKELY BE IN
PLACE OVER MANY EASTERN SIERRA HIGHWAYS, WITH SLICK ROAD
CONDITIONS ALSO POSSIBLE IN LOWER ELEVATIONS AROUND RENO-CARSON
CITY AND SUSANVILLE THROUGH THE WEDNESDAY MORNING COMMUTE.

MOST OF THE SNOW WILL TAPER OFF TO SNOW SHOWERS DURING THE DAY
WEDNESDAY AS THE MAIN TROUGH MOVES EAST. HOWEVER, THERE MAY BE
SOME MORE PERSISTENT SNOW BANDS OVER PARTS OF NORTHEAST CA AS SOME
OF THE MODEL GUIDANCE (ESPECIALLY THE GFS) KEEPS A SMALL AREA OF
UPPER LEVEL FORCING IN PLACE. THIS COULD LEAD TO A FEW EXTRA
INCHES OF SNOW ACCUMULATING IN PARTS OF WESTERN LASSEN AND CENTRAL
PLUMAS COUNTIES.

FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT, SHORTWAVE RIDGE MOVING
ACROSS THE REGION WILL BRING ANY LEFTOVER SNOW SHOWERS TO AN END,
ALTHOUGH ANY BREAKS IN CLOUD COVER WILL BE SHORT LIVED. THE RIDGE
AXIS MOVES EAST ACROSS THE GREAT BASIN BY THURSDAY NIGHT WITH
WIDESPREAD CIRRUS SPREADING INTO THE REGION, AS ANOTHER TROUGH
APPROACHES THE WEST COAST. MJD

.LONG TERM...FRIDAY THROUGH TUESDAY...

LOW PRESSURE OVER THE GULF OF ALASKA WILL DROP INTO THE PAC NW
FRIDAY, BRINGING ANOTHER CHANCE OF PRECIPITATION IN THE SIERRA AND
WESTERN NEVADA. THE TIMING OF THE FRONT HAS BEEN CONSISTENT OVER THE
LAST FEW DAYS, PUSHING THROUGH THE AREA ON FRIDAY. HOWEVER, THE
TRACK OF THE SHORTWAVE HAS BEEN CHANGING FROM RUN TO RUN, WHICH
LEADS TO LOWER CONFIDENCE IN THE OVERALL QPF/SNOW TOTALS FRIDAY
INTO SATURDAY. THE ECMWF THAT HAD BEEN SHOWING A SOLID QPF IN THE
SIERRA HAS NOW BACKED OFF WITH THE MOST RECENT 00Z RUN, LOOKING
MORE LIKE THE DRIER GFS. THIS IS UNFORTUNATE, BECAUSE NOW BOTH GFS
AND ECMWF ARE IN AGREEMENT THAT THE HEAVIEST PRECIP WILL REMAIN
NORTH IN WA/OR. SO EVEN THOUGH THIS STORM DOESN`T LOOK OVERLY
STRONG, IT MAY STILL CAUSE TRAVEL IMPACTS IN THE SIERRA FRIDAY
INTO SATURDAY MORNING.

BY SUNDAY, A RIDGE OF HIGH PRESSURE LOOKS TO BUILD OVER CA/NV WITH
LIGHT WAA CLOUDS/PRECIP ON SUNDAY AND MONDAY NEAR THE OREGON BORDER.
FOR THE REST OF THE FORECAST AREA, HIGH PRESSURE WILL MEAN LESS
CLOUDS, COOL AND DRY CONDITIONS, LIGHT WINDS, VALLEY INVERSIONS AND
POSSIBLE AIR QUALITY ISSUES EARLY NEXT WEEK. HOON

&&

.AVIATION...

LIGHT SNOW SHOWERS WILL CONTINUE IN THE SIERRA THIS MORNING WITH
PERIODS OF MVFR CIG/VIS AT KTRK/KTVL/KMMH. ADDITIONAL SNOW
ACCUMULATIONS THIS MORNING WILL BE MINIMAL, LESS THAN AN INCH.

BY TONIGHT, ANOTHER WAVE MOVES THROUGH THE SIERRA WITH 2-4" OF SNOW
POSSIBLE AT KTRK/KTVL/KMMH BY WEDNESDAY MORNING.

FOR KRNO/KCXP...A FEW SHOWERS AROUND THIS MORNING AND AGAIN TONIGHT,
BUT NO MAJOR RESTRICTIONS EXPECTED TO CIG/VIS. PERIODS OF MOUNTAIN
OBSCURATION AND LIGHT TURBULENCE/ICING EXPECTED THROUGH TONIGHT
AND INTO WEDNESDAY MORNING. HOON

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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









000
FXUS65 KREV 161151
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
351 AM PST TUE DEC 16 2014

.SYNOPSIS...

A SERIES OF WEAK WEATHER SYSTEMS WILL BRING PERIODS OF SNOW TO
THE SIERRA AND WESTERN NEVADA THIS WEEK. ALTHOUGH HEAVY SNOW IS
NOT EXPECTED, SLICK DRIVING CONDITIONS COULD AFFECT LOWER
ELEVATIONS AND IMPACT THE PEAK MORNING AND EVENING COMMUTE TIMES
THROUGH WEDNESDAY. ANOTHER ROUND OF LIGHT SNOW AND RAIN IS
POSSIBLE FRIDAY AND FRIDAY NIGHT.

&&

.SHORT TERM...

WEAK VORTICITY CENTER MOVING ACROSS THE CENTRAL SIERRA WILL KEEP
BANDS OF SNOW SHOWERS GOING UNTIL AROUND DAYBREAK. WHILE MOST OF
THE SHOWERS WILL REMAIN NEAR THE SIERRA CREST, SCATTERED BRIEF SNOW
SHOWERS WILL MAKE THEIR WAY INTO LOWER ELEVATIONS OF WESTERN NV
AND NORTHEAST CA. MOST ACTIVITY WILL DIMINISH LATER THIS MORNING
AS DYNAMICS WEAKEN AFTER THIS SYSTEM MOVES EAST OF THE REGION.
SNOW ACCUMULATIONS WILL BE MORE LOCALIZED COMPARED TO YESTERDAY.
IF A BAND IS ABLE TO PERSIST OVER THE SAME LOCATION FOR AN HOUR OR
MORE, AN INCH OR TWO COULD ACCUMULATE.

AFTER A SHORT BREAK IN PRECIPITATION THIS AFTERNOON AND EARLY
EVENING, NEXT TROUGH APPROACHES THE SIERRA TONIGHT. THIS SYSTEM
WILL INITIALLY HAVE A DECENT MOISTURE FEED AND FORCING, BUT WILL
ALSO WEAKEN AND ELONGATE AS IT REACHES THE SIERRA. THE MOST LIKELY
TIMING FOR A PERIOD OF STEADY SNOW WILL BE DURING THE LATE NIGHT
AND EARLY MORNING HOURS NEAR THE SIERRA. THIS WILL BE A SHORT
DURATION EVENT WHICH WILL KEEP SNOWFALL TOTALS BELOW ADVISORY
CRITERIA. SNOW AMOUNTS OF 1-4 INCHES ARE EXPECTED FROM WESTERN
LASSEN COUNTY ACROSS THE TAHOE BASIN AND INTO WESTERN MONO COUNTY,
WITH 3-6 INCHES NEAR THE SIERRA CREST. FOR EASTERN LASSEN AND INTO
FAR WESTERN NV, ACCUMULATIONS OF 1 INCH OR LESS ARE EXPECTED.
DESPITE THE LOW SNOW TOTALS, CHAIN CONTROLS WILL LIKELY BE IN
PLACE OVER MANY EASTERN SIERRA HIGHWAYS, WITH SLICK ROAD
CONDITIONS ALSO POSSIBLE IN LOWER ELEVATIONS AROUND RENO-CARSON
CITY AND SUSANVILLE THROUGH THE WEDNESDAY MORNING COMMUTE.

MOST OF THE SNOW WILL TAPER OFF TO SNOW SHOWERS DURING THE DAY
WEDNESDAY AS THE MAIN TROUGH MOVES EAST. HOWEVER, THERE MAY BE
SOME MORE PERSISTENT SNOW BANDS OVER PARTS OF NORTHEAST CA AS SOME
OF THE MODEL GUIDANCE (ESPECIALLY THE GFS) KEEPS A SMALL AREA OF
UPPER LEVEL FORCING IN PLACE. THIS COULD LEAD TO A FEW EXTRA
INCHES OF SNOW ACCUMULATING IN PARTS OF WESTERN LASSEN AND CENTRAL
PLUMAS COUNTIES.

FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT, SHORTWAVE RIDGE MOVING
ACROSS THE REGION WILL BRING ANY LEFTOVER SNOW SHOWERS TO AN END,
ALTHOUGH ANY BREAKS IN CLOUD COVER WILL BE SHORT LIVED. THE RIDGE
AXIS MOVES EAST ACROSS THE GREAT BASIN BY THURSDAY NIGHT WITH
WIDESPREAD CIRRUS SPREADING INTO THE REGION, AS ANOTHER TROUGH
APPROACHES THE WEST COAST. MJD

.LONG TERM...FRIDAY THROUGH TUESDAY...

LOW PRESSURE OVER THE GULF OF ALASKA WILL DROP INTO THE PAC NW
FRIDAY, BRINGING ANOTHER CHANCE OF PRECIPITATION IN THE SIERRA AND
WESTERN NEVADA. THE TIMING OF THE FRONT HAS BEEN CONSISTENT OVER THE
LAST FEW DAYS, PUSHING THROUGH THE AREA ON FRIDAY. HOWEVER, THE
TRACK OF THE SHORTWAVE HAS BEEN CHANGING FROM RUN TO RUN, WHICH
LEADS TO LOWER CONFIDENCE IN THE OVERALL QPF/SNOW TOTALS FRIDAY
INTO SATURDAY. THE ECMWF THAT HAD BEEN SHOWING A SOLID QPF IN THE
SIERRA HAS NOW BACKED OFF WITH THE MOST RECENT 00Z RUN, LOOKING
MORE LIKE THE DRIER GFS. THIS IS UNFORTUNATE, BECAUSE NOW BOTH GFS
AND ECMWF ARE IN AGREEMENT THAT THE HEAVIEST PRECIP WILL REMAIN
NORTH IN WA/OR. SO EVEN THOUGH THIS STORM DOESN`T LOOK OVERLY
STRONG, IT MAY STILL CAUSE TRAVEL IMPACTS IN THE SIERRA FRIDAY
INTO SATURDAY MORNING.

BY SUNDAY, A RIDGE OF HIGH PRESSURE LOOKS TO BUILD OVER CA/NV WITH
LIGHT WAA CLOUDS/PRECIP ON SUNDAY AND MONDAY NEAR THE OREGON BORDER.
FOR THE REST OF THE FORECAST AREA, HIGH PRESSURE WILL MEAN LESS
CLOUDS, COOL AND DRY CONDITIONS, LIGHT WINDS, VALLEY INVERSIONS AND
POSSIBLE AIR QUALITY ISSUES EARLY NEXT WEEK. HOON

&&

.AVIATION...

LIGHT SNOW SHOWERS WILL CONTINUE IN THE SIERRA THIS MORNING WITH
PERIODS OF MVFR CIG/VIS AT KTRK/KTVL/KMMH. ADDITIONAL SNOW
ACCUMULATIONS THIS MORNING WILL BE MINIMAL, LESS THAN AN INCH.

BY TONIGHT, ANOTHER WAVE MOVES THROUGH THE SIERRA WITH 2-4" OF SNOW
POSSIBLE AT KTRK/KTVL/KMMH BY WEDNESDAY MORNING.

FOR KRNO/KCXP...A FEW SHOWERS AROUND THIS MORNING AND AGAIN TONIGHT,
BUT NO MAJOR RESTRICTIONS EXPECTED TO CIG/VIS. PERIODS OF MOUNTAIN
OBSCURATION AND LIGHT TURBULENCE/ICING EXPECTED THROUGH TONIGHT
AND INTO WEDNESDAY MORNING. HOON

&&

.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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