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3:40 p.m. Sunday: Latest Weather Service Bulletins

SNOWPACK (SNOW WATER EQUIVALENT) IN SIERRA WENT FROM 40-50% OF NORMAL PRIOR TO THE STORM TO 95-124% TODAY!! STORM CONTINUES WINDING DOWN WITH THE FINAL WAVE MOVING THROUGH NORTHWESTERN CALIFORNIA THIS AFTERNOON. TROUGHS UPSTREAM JET IS DIGGING THE FINAL WAVE SOUTH THROUGH THE BAY AREA AND INTO SOUTHERN CALIFORNIA.

AN ORGANIZED CONVECTIVE BAND OVER FAR NORTHERN CA THAT WAS ORIGINALLY FORCED BY THIS JET CONTINUES TO WEAKEN AND SHEAR APART WITH CLOUD TOPS GRADUALLY WARMING. THIS CONVECTIVE BAND DOES LOOK TO HOLD TOGETHER LONG ENOUGH TO MOVE THROUGH THE CENTRAL VALLEY AND INTO THE WESTERN SLOPES OF THE SIERRA BEFORE FALLING APART AS IT GETS TO THE SIERRA CREST.



WITH COLD AIR OVER US TODAY…DIURNALLY DRIVEN SNOW SHOWERS DEVELOPED AND LOOK TO CONTINUE INTO EARLY EVENING. THEN THIS LAST WAVE WILL PUSH IN AND PRODUCE ADDITIONAL SNOW SHOWERS INTO THE SIERRA WITH SCATTERED SNOW SHOWERS OVER WESTERN NEVADA.

SIERRA COULD STILL PICK UP 3-6 INCHES OR SO ABOVE 7000 FEET DUE TO VERY DRY SNOW THROUGH MONDAY…BUT NOTHING SIGNIFICANT.



LIGHT SNOW SHOWERS IN THE SIERRA AND SURPRISE VALLEY THROUGH MONDAY WITH SCATTERED SNOW SHOWERS ELSEWHERE. BRIEF SHORTWAVE RIDGE TO BUILD OVER THE AREA MONDAY NIGHT INTO TUESDAY MINORING BEFORE NEXT SYSTEM MOVES INTO THE SIERRA TUESDAY AFTERNOON AND EVENING.

THIS FAST MOVING STORM WILL LIKELY BRING 8-16 INCHES OF SNOW TO THE SIERRA FROM THE TAHOE BASIN NORTH WITH LIGHTER AMOUNTS SOUTH OF THE TAHOE BASIN. SCATTERED SNOW SHOWERS TO LINGER INTO WEDNESDAY.

SNOW ACCUMULATIONS TUESDAY AFTERNOON AND EVENING ON VALLEY FLOORS COULD ADD UP TO A COUPLE INCHES.

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WEDNESDAY NIGHT THROUGH SUNDAY…

THE NEXT OVERRUNNING EVENT TO OCCUR WEDNESDAY NIGHT AND THURSDAY MORNING AS A FAST-MOVING SHORT WAVE MOVES THROUGH OREGON. THIS SYSTEM IS SHOWING A MODEST SUBTROPICAL TAP WITH THE OVERRUNNING EVENT FOR AREAS NORTH OF HIGHWAY 50…WITH 1.3-INCH PWATS INDICATED BY THE GFS JUST NORTH OF SAN FRANCISCO BY 12Z THURSDAY (WITH .61-INCH PWATS OVER RENO).

GFS AND NAM MODEL SOUNDINGS INDICATE DEEP SATURATION WITH NEARLY ISOTHERMAL TEMPERATURE PROFILES BELOW 650 MB. DEPENDING ON HOW WARM WE GET WEDNESDAY AFTERNOON… THIS INDICATES SNOW LEVELS NEAR/AT ALL VALLEY FLOORS. WITH LITTLE FORCING OTHER THAN OVERRUNNING…

AMOUNTS APPEAR LIGHT WITH 12Z GFS QPF INDICATING PERHAPS 3-6 INCHES AT BEST IN THE NORTHERN SIERRA…WITH MAYBE UP TO 2 INCHES FOR PORTIONS OF WESTERN NEVADA NORTH OF HIGHWAY 50.

MODELS PUSH AT LEAST THE SOUTHERN 2/3RDS OF THE CWA INTO THE WARM SECTOR (AT LEAST A “WARMER SECTOR”). THIS WILL CUTOFF ANY ADDITIONAL PRECIPITATION IN THE BASIN AS MOISTURE THINS OUT BEHIND THE WARM ADVECTION. HOWEVER…I LEFT LOW POPS AS IS THURSDAY WITH TIMING UNCERTAINTIES THAT ARE INHERENT AT DAY 4 WITH FAST MOVING SYSTEMS. I ALSO LEFT THE INHERITED SMATTERING OF LOW POPS FOR THURSDAY NIGHT GIVEN 12Z GFS ENSEMBLE PROBABILISTIC QPF.

HOWEVER… THIS MAY NEED TO BE RESTRICTED TO THE FAR NORTH AT BEST AS THE GFS ENSEMBLE PROBABILISTICS ARE AT POOR RESOLUTION WHICH WOULD NOT SHOW LEE SIDE OF THE SIERRA DRYING EFFECTS VERY WELL (I WOULD EXPECT DOWNSLOPING GIVEN THE STABLE/SHALLOW MOISTURE PROFILES).

IT LOOKS LIKE THE REGION WILL SHIFT INTO A LONGWAVE RIDGE PATTERN THAT…ACCORDING TO THE GFS ENSEMBLE…COULD PERSIST FOR AT LEAST 10 DAYS. CLIMATOLOGY GIVES MORE CONFIDENCE TO THE GFS ENSEMBLE …AS AN UPPER RIDGE IS COMMON FOR AT LEAST A PORTION OF JANUARY. THE UPPER RIDGE MEANS DRY WEATHER WITH NEAR OR SLIGHTLY BELOW NORMAL TEMPERATURES (IN LOWER VALLEYS WITH ANY LEFTOVER SNOW COVER) UNDER PERSISTENT LOW LEVEL INVERSION CONDITIONS AIDED BY WEAK WINTER SUN.

ISOLATED SNOW SHOWERS IN THE SIERRA TO BRIEFLY REDUCE CIGS/VSBYS TONIGHT AND EARLY MONDAY. ELSEWHERE…VFR WITH FEW-SCT CUMULUS AND SCT-BKN HIGH DECKS THROUGH MONDAY.

NATIONAL WEATHER SERVICE RENO NV

1245 PM PST SUN JAN 6 2008 .

CANCELLED WINTER STORM WARNINGS FOR TAHOE AND MONO COUNTIES EARLY AS SNOW RATES WILL NOT ADD UP TO NECESSARY ACCUMULATIONS. ALTHOUGH…SNOW SHOWERS WILL CONTINUE THROUGH MONDAY. THE LAST WAVE OF THIS SYSTEM WILL MOVE INTO THE SIERRA TONIGHT BUT WASHES OUT JUST WEST OF THE SIERRA CREST SO AMOUNTS DONT LOOK IMPRESSIVE EAST OF THE CREST.

LATEST RUNS FOR THE TUESDAY SYSTEM HAVE COME IN SLIGHTLY COLDER AND LOOKS TO BE MAINLY A SNOW EVENT FOR THE CWA. THIS SYSTEM WILL FAIL IN COMPARISON TO THIS PAST STORM.

HIGHEST SNOW TOTALS SEEN SO FAR FROM THIS STORM ARE 8-11 FEET AT KIRKWOOD SKI RESORT WITH 5-9 FEET FROM ALL OTHER RESORTS. SEE UPDATED STORM TOTALS ON OUR WEBSITE AT http://WWW.WRH.NOAA.GOV/RENO.

SHORT WAVE MOVING THROUGH THE AREA AT THIS TIME…WITH BANDS OF SNOW IN WESTERN NV AND SOME SHOWERS NEAR THE SIERRA CREST. A FEW FEATURES OF INTEREST INCLUDE THE JET STREAK MOVING INTO SRN CA…BAND OF CONVECTION NEAR 40N 130W AND SHORT WAVE AT 43N 140W. MODELS INITIALIZED FAIRLY WELL AND WILL USE A BLEND.

AS FOR TODAY…WITH BANDS OF SHOWERS EXITING NORTHWEST NEVADA…WILL ALLOW ADVISORY/WARNINGS TO EXPIRE FOR THESE AREAS. EXPECTING ONLY SCATTERED SHOWERS FROM HERE ON OUT. FURTHER SOUTH…THESE BANDS WILL AFFECT YERINGTON/HAWTHORNE AREAS SO WILL CONTINUE THE WARNING…BUT MAY END UP CANCELING IT EARLY A LITTLE LATER THIS MORNING WHEN THOSE BANDS CLEAR. AS FAR AS THE SIERRA…MODEL PROGGED PRECIP IS VERY LIGHT TODAY AND THOUGHT ABOUT CANCELING ALL THOSE EARLY AS WELL. TWO THINGS HAVE STOPPED ME. ONE…NUMEROUS SNOW SHOWERS CONTINUE NEAR AND EAST OF THE CREST FROM SUSANVILLE SOUTH TO MAMMOTH. TWO…THE BAND OF CONVECTION JUST OFF THE COAST. MODELS SLOW IT DOWN AND WEAKEN IT AND THIS IS DEFINITELY POSSIBLE. HOWEVER…IF IT HOLDS TOGETHER AND MOVES IT…A 6-HR PERIOD OF MODERATE TO HEAVY SNOW IS POSSIBLE. IF THIS WERE TO HAPPEN…ZONE 71 WOULD NEED TO BE EXTENDED TO 03Z SIMILAR TO TAHOE/MONO. OVERALL…EXPECT SHOWERS TO CONTINUE IN THE SIERRA TODAY WITH SCATTERED LIGHTER SNOW SHOWERS IN WESTERN NV. TONIGHT…THE MODELS SHOW THE SHORT WAVE AT 140W MOVING INTO THE AREA WITH SOME MORE SNOW IN THE SIERRA BUT AMOUNTS LOOK LIGHT AT THIS TIME. NOT SURE HOW MUCH SPILLOVER THERE WILL BE AS THE FORCING IS NOT GREAT. WILL LEAVE FORECAST ALONE WITH A FEW INCHES OF SNOW POSSIBLE IN THE SIERRA.

EXPECT SOME CLEARING ON MONDAY WITH MAINLY A FEW SNOW SHOWERS IN THE SIERRA DURING THE MORNING. THE NEXT SYSTEM FOR TUESDAY WILL BEGIN TO SPREAD CLOUDS ACROSS THE AREA MONDAY NIGHT. THINKING THAT THE THICKER CLOUDS WILL NOT ARRIVE UNTIL AFTER 06Z SO WILL HAVE A REASONABLY COLD NIGHT…SIMILAR TO WHAT GUIDANCE SUGGESTS.

AS FOR TUESDAY…I AM NOT REAL IMPRESSED WITH THIS SYSTEM. JET BECOMES SOMEWHAT FRACTURED OVER US AND IT WILL GLANCE THE NORTHERN HALF OF THE AREA. WHILE THERE WILL BE SOME WARM AIR ADVECTION WITH H7 TEMPS TO -4C…BELIEVE MOST PRECIP WILL BE IN THE FORM OF SNOW. INVERSIONS WILL BE STRONG ENOUGH TO KEEP THE H7 WINDS OF 50 KTS OFF THE SURFACE AS EXTENSIVE CLOUD COVER WILL INHIBIT MUCH INSOLATION.

CURRENT THINKING IS TO KEEP SNOW LEVELS NEAR 5000 FEET. PRECIP AMOUNTS UP TO 1 INCH POSSIBLE NEAR THE CREST SO IT LOOKS LIKE AN ADVISORY SITUATION AT BEST. ALSO…WITH THE FORCING LIMITED FROM THE JET…MILD FRONTOGENESIS AND A SOMEWHAT STABLE PROFILE DO NOT EXPECT MUCH IN THE WAY OF SPILLOVER. THE EXCEPTION WILL BE NORTH OF A SUSANVILLE TO GERLACH LINE WHERE THE WARM AIR ADVECTION WILL ACTUALLY FAVOR SPILLOVER WITH LIGHT AMOUNTS. WALLMANN .

LONG TERM…WEDNESDAY THROUGH SATURDAY… UNSETTLED WEATHER WILL CONTINUE THROUGH THE EXTENDED. ON WEDNESDAY WEAK RIDGING IS PROGGED TO BE BUILDING INTO THE WEST COAST IN THE WAKE OF A RETREATING UPPER TROUGH MOVING INTO THE NRN PLAINS. PROGRESSIVE FLOW WILL BRING THE NEXT IN A SERIES OF SYSTEMS INTO THE PACIFIC NW ON THURSDAY. THE GFS AND ECMWF KEEP THIS SYSTEM FAR TO OUR NORTH AS IT MOVES TO WASHINGTON STATE BY 00Z FRIDAY. A VORT MAX MOVING THROUGH THE BASE OF THE TROUGH IS PROGGED TO PUSH A COLD FRONT ACROSS OREGON AND INTO THE NRN SIERRA. HOWEVER THE MAIN DYNAMICS WITH THIS SYSTEM REMAIN NORTH SO FRONTOLYSIS SHOULD OCCUR AS THE FRONT TRAVERSES THE NRN SIERRA.

ON FRIDAY THIS WEAKENING SYSTEM MOVES TO THE NRN ROCKIES AS AN UPPER LOW STRENGTHENS NEAR 45N AND 150W. BOTH THE GFS AND EURO SHOW SIMILAR SCENARIOS BY BRINGING AN INITIAL SHORTWAVE EAST TOWARD BRITISH COLUMBIA BY 00Z SATURDAY. THE ERN PACIFIC RIDGE STRENGTHENS SUBSTANTIALLY ON SATURDAY AS THE MAIN GULF OF ALASKA LOW DEEPENS.

WITH NO REAL WARM AIR ADVECTION OCCURRING UNTIL POSSIBLY SATURDAY TEMPERATURES SHOULD REMAIN NEAR NORMAL. WILL CONTINUE WITH A MENTION OF PRECIP ACROSS THE ENTIRE CWFA WEDNESDAY THROUGH THURSDAY NIGHT. RIDGING ON FRIDAY WILL HELP TO KEEP PRECIP TO OUR NORTH. WILL ADD PRECIP TO THE FAR NWRN ZONES ON SATURDAY WITH THE SHORTWAVE PROGGED TO MOVE INTO THE NWRN CONUS.

AVIATION… MVFR WITH LCL IFR CONDITIONS WILL CONTINUE THROUGH 15Z ACROSS THE ERN SIERRA AND WRN NEVADA. SHSN WILL DECREASE AT KRNO AND KLOL THIS MORNING. HOWEVER SHSN WILL CONTINUE AT KTVL AND KTRK THROUGH 00Z MONDAY.

Occasional snow showers, mainly before 4pm. High near 26. Southwest wind between 10 and 15 mph. Chance of precipitation is 80%. Total daytime snow accumulation of 2 to 4 inches possible.

Occasional snow showers, mainly between 10pm and 4am. Low around 12. South wind around 10 mph. Chance of precipitation is 80%. New snow accumulation of 2 to 4 inches possible.

A chance of snow showers before 10am, then a chance of snow showers after 4pm. Mostly cloudy, with a high near 28. West wind around 10 mph. Chance of precipitation is 40%.

Periods of snow, mainly after 4am. Low around 16. West wind between 10 and 15 mph, with gusts as high as 25 mph. Chance of precipitation is 90%.

Periods of snow. High near 33. Southwest wind around 15 mph, with gusts as high as 25 mph. Chance of precipitation is 90%.

Periods of snow, mainly before 4am. Low around 15. Breezy. Chance of precipitation is 80%.

A 40 percent chance of snow showers. Mostly cloudy, with a high near 38.

A chance of snow showers. Mostly cloudy, with a low around 16.

A chance of snow showers. Partly sunny, with a high near 36.

A slight chance of snow showers. Mostly cloudy, with a low around 16.

Mostly sunny, with a high near 37.

Partly cloudy, with a low around 16.

Mostly sunny, with a high near 35.

URGENT – WINTER WEATHER MESSAGE

NATIONAL WEATHER SERVICE RENO NV

…MAJOR WINTER STORM WILL SLOWLY WIND DOWN TODAY..

.MODERATE TO HEAVY SNOW AND GUSTY WINDS WILL CONTINUE TO CREATE

DANGEROUS CONDITIONS IN THE SIERRA AND LAKE TAHOE BASIN.

MODERATE TO HEAVY SNOW AND LOCALLY GUSTY WINDS WILL CONTINUE ACROSS THE SIERRA TODAY.

NATIONAL WEATHER SERVICE RENO NV

403 AM PST SUN JAN 6 2008

SHORT WAVE MOVING THROUGH THE AREA AT THIS TIME … WITH BANDS OF SNOW IN WESTERN NV AND SOME SHOWERS NEAR THE SIERRA CREST. A FEW FEATURES OF INTEREST INCLUDE THE JET STREAK MOVING INTO SRN CA …

BAND OF CONVECTION NEAR 40N 130W AND SHORT WAVE AT 43N 140W. MODELS INITIALIZED FAIRLY WELL AND WILL USE A BLEND.

AS FOR TODAY…IN THE SIERRA…MODEL PROGGED PRECIP IS VERY LIGHT TODAY AND THOUGHT ABOUT CANCELING ALL THOSE EARLY AS WELL. TWO THINGS HAVE STOPPED ME. ONE…NUMEROUS SNOW SHOWERS CONTINUE NEAR AND EAST OF THE CREST FROM SUSANVILLE SOUTH TO MAMMOTH. TWO…THE BAND OF CONVECTION JUST OFF THE COAST. MODELS SLOW IT DOWN AND WEAKEN IT AND THIS IS DEFINITELY POSSIBLE. HOWEVER…IF IT HOLDS TOGETHER AND MOVES IN…A 6-HR PERIOD OF MODERATE TO HEAVY SNOW IS POSSIBLE.

IF THIS WERE TO HAPPEN…ZONE 71 WOULD NEED TO BE EXTENDED TO 03Z SIMILAR TO TAHOE/MONO. OVERALL…EXPECT SHOWERS TO CONTINUE IN THE SIERRA TODAY WITH SCATTERED LIGHTER SNOW SHOWERS IN WESTERN NV.

THE MODELS SHOW THE SHORT WAVE AT 140W MOVING INTO THE AREA WITH SOME MORE SNOW IN THE SIERRA BUT AMOUNTS LOOK LIGHT AT THIS TIME. NOT SURE HOW MUCH SPILLOVER THERE WILL BE AS THE FORCING IS NOT GREAT. WILL LEAVE FORECAST ALONE WITH A FEW INCHES OF SNOW POSSIBLE IN THE SIERRA.

EXPECT SOME CLEARING ON MONDAY WITH MAINLY A FEW SNOW SHOWERS IN THE SIERRA DURING THE MORNING. THE NEXT SYSTEM FOR TUESDAY WILL BEGIN TO SPREAD CLOUDS ACROSS THE AREA MONDAY NIGHT. THINKING THAT THE THICKER CLOUDS WILL NOT ARRIVE UNTIL AFTER 06Z SO WILL HAVE A REASONABLY COLD NIGHT…SIMILAR TO WHAT GUIDANCE SUGGESTS.

I AM NOT REAL IMPRESSED WITH THIS SYSTEM. JET BECOMES SOMEWHAT FRACTURED OVER US AND IT WILL GLANCE THE NORTHERN HALF OF THE AREA. WHILE THERE WILL BE SOME WARM AIR ADVECTION WITH H7 TEMPS TO -4C…BELIEVE MOST PRECIP WILL BE IN THE FORM OF SNOW.

INVERSIONS WILL BE STRONG ENOUGH TO KEEP THE H7 WINDS OF 50 KTS OFF THE SURFACE AS EXTENSIVE CLOUD COVER WILL INHIBIT MUCH INSOLATION. CURRENT THINKING IS TO KEEP SNOW LEVELS NEAR 5000 FEET. PRECIP AMOUNTS UP TO 1 INCH POSSIBLE NEAR THE CREST SO IT LOOKS LIKE AN ADVISORY SITUATION AT BEST.

WEDNESDAY THROUGH SATURDAY…

UNSETTLED WEATHER WILL CONTINUE THROUGH THE EXTENDED. ON WEDNESDAY WEAK RIDGING IS PROGGED TO BE BUILDING INTO THE WEST COAST IN THE WAKE OF A RETREATING UPPER TROUGH MOVING INTO THE NRN PLAINS.

PROGRESSIVE FLOW WILL BRING THE NEXT IN A SERIES OF SYSTEMS INTO THE PACIFIC NW ON THURSDAY. THE GFS AND ECMWF KEEP THIS SYSTEM FAR TO OUR NORTH AS IT MOVES TO WASHINGTON STATE BY 00Z FRIDAY. A VORT MAX MOVING THROUGH THE BASE OF THE TROUGH IS PROGGED TO PUSH A COLD FRONT ACROSS OREGON AND INTO THE NRN SIERRA. HOWEVER THE MAIN DYNAMICS WITH THIS SYSTEM REMAIN NORTH SO FRONTOLYSIS SHOULD OCCUR AS THE FRONT TRAVERSES THE NRN SIERRA.

ON FRIDAY THIS WEAKENING SYSTEM MOVES TO THE NRN ROCKIES AS AN UPPER LOW STRENGTHENS NEAR 45N AND 150W. BOTH THE GFS AND EURO SHOW SIMILAR SCENARIOS BY BRINGING AN INITIAL SHORTWAVE EAST TOWARD BRITISH COLUMBIA BY 00Z SATURDAY. T

HE ERN PACIFIC RIDGE STRENGTHENS SUBSTANTIALLY ON SATURDAY AS THE MAIN GULF OF ALASKA LOW DEEPENS. WITH NO REAL WARM AIR ADVECTION OCCURRING UNTIL POSSIBLY SATURDAY TEMPERATURES SHOULD REMAIN NEAR NORMAL.

WILL CONTINUE WITH A MENTION OF PRECIP ACROSS THE ENTIRE CWFA WEDNESDAY THROUGH THURSDAY NIGHT. RIDGING ON FRIDAY WILL HELP TO KEEP PRECIP TO OUR NORTH. WILL ADD PRECIP TO THE FAR NWRN ZONES ON SATURDAY WITH THE SHORTWAVE PROGGED TO MOVE INTO THE NWRN CONUS.

MVFR WITH LCL IFR CONDITIONS WILL CONTINUE THROUGH 15Z ACROSS THE ERN SIERRA AND WRN NEVADA. SHSN WILL DECREASE AT KRNO AND KLOL THIS MORNING. HOWEVER SHSN WILL CONTINUE AT KTVL AND KTRK THROUGH 00Z MONDAY.


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