564  
FXUS66 KSTO 291100  
AFDSTO  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SACRAMENTO CA  
300 AM PST THU FEB 29 2024  
   
SYNOPSIS
 
 
ACTIVE PATTERN RETURNS TOMORROW INTO NEXT WEEKEND BRINGING  
WIDESPREAD PRECIPITATION, EXTREMELY HEAVY MOUNTAIN SNOW WITH  
BLIZZARD CONDITIONS, STRONG WINDS, AND LOW ELEVATION (1500-3000)  
SNOW ACCUMULATIONS.  
 

 
   
DISCUSSION
 
TODAY THROUGH SATURDAY.  
 
KEY POINTS OF LATE WEEK-WEEKEND STORM:  
 
* EXTREMELY HEAVY SNOW WITH BLIZZARD CONDITIONS EXPECTED IN THE  
SIERRA, HEAVIEST THIS AFTERNOON THROUGH SATURDAY. STORM TOTAL  
SNOWFALL INTO EARLY SUNDAY IS CURRENTLY PROJECTED AT 5 TO 10+  
FEET FOR ELEVATIONS ABOVE 5,000 FEET, LOCALLY HIGHER AMOUNTS OF  
12+ FEET ARE POSSIBLE AT PEAKS, WITH SIGNIFICANT DISRUPTIONS TO  
DAILY LIFE LIKELY.  
 
* MOUNTAIN TRAVEL WILL BE EXTREMELY DANGEROUS TO IMPOSSIBLE,  
ESPECIALLY THIS AFTERNOON THROUGH SATURDAY.  
 
* SIGNIFICANT SNOW ACCUMULATIONS ARE EXPECTED ABOVE 3000 FEET.  
COLD AIR WILL DROP SNOW LEVELS DOWN TO 1000-2000 BY THE  
WEEKEND, WITH LIGHT ACCUMULATIONS POSSIBLE AT THOSE LEVELS.  
 
* WIND GUSTS TO 55 TO 75 MPH ARE EXPECTED OVER THE MOUNTAINS.  
EXPECT SNOW RATES OF 2-4+" PER HOUR. THESE WILL COMBINE TO BRING  
WHITEOUT CONDITIONS WITH NEAR ZERO VISIBILITY AT TIMES BEGINNING  
TODAY, BUT ESPECIALLY FRIDAY AND SATURDAY.  
 
* STRONG WINDS ARE FORECAST IN THE CENTRAL VALLEY WITH GUSTS OF  
40 TO 55 MPH FROM YUBA CITY NORTHWARD TODAY, AND FROM MODESTO  
NORTHWARD ON FRIDAY.  
 
 
---------------------------------------------------------------  
 
THE DRY WEATHER WILL RAPIDLY COME TO AN END EARLY THIS MORNING AS  
THE STRONG WINTER STORM MOVES INTO THE REGION WITH A CLASSIC HEAVY  
SNOW PRODUCER FOR THE MOUNTAINS SET TO AFFECT THE REGION THROUGH  
SATURDAY. RADAR SHOWS PRECIPITATION CURRENTLY MOVING ACROSS  
NORTHWEST CALIFORNIA. SNOW WILL DEVELOP OVER THE NORTHERN SIERRA  
AROUND SUNRISE WITH HEAVY SNOW EXPECTED BY LATE MORNING. IN THE  
VALLEY, SPOTTY LIGHTER PRECIPITATION WILL BE POSSIBLE THIS MORNING  
WITH A PERIOD OF MODERATE TO HEAVY RAIN EXPECTED TO MOVE SOUTH  
DURING THE AFTERNOON WITH THE FRONT, POSSIBLY ACCOMPANIED BY A  
LITTLE THUNDER. GUSTY SOUTHERLY WIND IS ALREADY PICKING UP ACROSS  
THE REGION AS THE SURFACE PRESSURE GRADIENT TIGHTENS AHEAD OF THE  
APPROACHING FRONT. GUSTS OF 20-30 MPH ARE ALREADY BEING OBSERVED  
ACROSS THE NORTHERN HALF OF THE SACRAMENTO VALLEY AND IN THE  
MOUNTAINS.  
 
EXTREMELY DANGEROUS TO IMPOSSIBLE MOUNTAIN TRAVEL IS EXPECTED  
INTO THE WEEKEND. A BLIZZARD WARNING HAS BEEN ISSUED FOR THE  
NORTHEAST FOOTHILLS, MOTHERLODE, SIERRA, AND WESTERN PLUMAS/LASSEN  
AREA ABOVE 2000 FEET AND A WINTER STORM WARNING HAS BEEN ISSUED  
FOR THE COASTAL RANGE, SHASTA COUNTY MOUNTAINS, AND BURNEY BASIN.  
SNOW RATES OF 2-4+" INCHES ARE EXPECTED, WITH ROAD CLOSURES,  
WHITE-OUT CONDITIONS AND NEAR ZERO VISIBILITIES AT TIMES. VERY  
STRONG WINDS, COMBINED WITH VERY HEAVY SNOWFALL COULD CAUSE  
EXTENSIVE TREE DAMAGE AND EXTENDED POWER OUTAGES. BLIZZARD  
CONDITIONS ARE EXPECTED THROUGH SATURDAY. SNOW LEVELS WILL START  
OUT AROUND 5000 TO 6000 FEET TODAY, LOWERING TO 3000 TO 4500 FEET  
FRIDAY, THEN DOWN TO 1000 TO 2000 FEET SATURDAY. TOTAL SNOWFALL  
WILL BE MEASURED IN FEET FROM THIS EVENT, WITH THE NATIONAL BLEND  
OF MODELS (NBM) SUGGESTING 12 FEET IN THE SIERRA. AREAS ALONG I-5  
IN SHASTA COUNTY WILL LIKELY SEE UP TO A FOOT OF SNOW OR MORE, SO  
SIGNIFICANT TRAVEL DELAYS AND ROAD CLOSURES ARE POSSIBLE.  
 
GUSTY WINDS WILL ALSO BRING MODERATE IMPACTS TO THE REGION THROUGH  
FRIDAY. STRONGEST WINDS WILL BE NORTH OF SACRAMENTO TODAY, BUT  
WILL LIKELY SPREAD SOUTH ON FRIDAY AS THE NEXT WAVE MOVES THROUGH.  
A WIND ADVISORY REMAINS IN EFFECT.  
 
A FEW THUNDERSTORMS WILL BE POSSIBLE TODAY AS THE INITIAL FRONT  
MOVES SOUTH THIS AFTERNOON AND EVENING. THE EC EXTREME FORECAST  
INDEX (EFI) HIGHLIGHTS MOST OF INTERIOR NORCAL FOR POSSIBLE  
THUNDERSTORM DEVELOPMENT ON FRIDAY AND SATURDAY AFTERNOON, AND THE  
NBM SUPPORTS THIS WITH A 10-20% CHANCE OF T-STORM DEVELOPMENT  
FRIDAY AND SATURDAY AFTERNOON/EVENING. HAZARDS FROM ANY T-STORMS  
THAT DEVELOP WILL INCLUDE ADDITIONAL GUSTY WINDS, SMALL HAIL,  
BRIEF HEAVY RAIN AND LIGHTNING. AS FOR AS RAINFALL GOES, MUCH OF  
THE VALLEY WILL LIKELY SEE GENERALLY LESS THAN 1.50" INCHES  
THROUGH SATURDAY NIGHT. THE FOOTHILLS WILL SEE 2-4 INCHES AND THE  
MOUNTAINS WILL SEE 4-8 INCHES WITH LOCALLY HEAVIER AMOUNTS.  
 
THE TIME TO PREPARE FOR THIS *SIGNIFICANTLY* IMPACTFUL WINTER  
STORM IS NOW! MOUNTAIN TRAVEL IS HIGHLY DISCOURAGED WHILE THE  
WARNINGS ARE IN EFFECT!  
 

 
   
EXTENDED DISCUSSION (MONDAY THROUGH THURSDAY)
 
 
LINGERING MOUNTAIN SNOW SHOWERS POSSIBLE MONDAY, OTHERWISE DRIER  
WEATHER EXPECTED INTO TUESDAY AS SHORT WAVE RIDGING MOVES THROUGH.  
UPSTREAM SHORT WAVE TROUGHS PROGGED INLAND MIDWEEK BRINGING MORE  
WIDESPREAD LIGHT TO MODERATE PRECIP WEDNESDAY INTO THURSDAY. NBM  
SHOWING SNOW LEVELS OF 2500-3500 FEET DURING THIS PERIOD.  
 

 
   
AVIATION
 
 
WIDESPREAD MVFR/IFR WITH AREAS LIFR OVER THE MTNS NEXT 24 HRS AS  
PAC STORM MOVES INLAND. IN CENTRAL VLY, SLY SFC WIND 15-30 KTS  
WITH LCL GUSTS UP TO 45 KNOTS. OVER MTNS, AREAS SWLY SFC WIND  
GUSTS 40-60 KTS. ISOLATED -TSRA POSSIBLE IN N SAN JOAQUIN VLY BTWN  
22Z-04Z.  
 

 
   
STO WATCHES/WARNINGS/ADVISORIES
 
 
WINTER STORM WARNING UNTIL 10 AM PST SUNDAY FOR BURNEY BASIN /  
EASTERN SHASTA COUNTY-MOUNTAINS SOUTHWESTERN SHASTA COUNTY TO  
WESTERN COLUSA COUNTY-SHASTA LAKE AREA / NORTHERN SHASTA COUNTY.  
 
WIND ADVISORY UNTIL 4 AM PST SATURDAY FOR CARQUINEZ STRAIT AND  
DELTA-CENTRAL SACRAMENTO VALLEY-MOTHERLODE-MOUNTAINS  
SOUTHWESTERN SHASTA COUNTY TO WESTERN COLUSA COUNTY-NORTHEAST  
FOOTHILLS/SACRAMENTO VALLEY-NORTHERN SACRAMENTO VALLEY-NORTHERN  
SAN JOAQUIN VALLEY-SHASTA LAKE AREA / NORTHERN SHASTA COUNTY-  
SOUTHERN SACRAMENTO VALLEY.  
 
BLIZZARD WARNING UNTIL 10 AM PST SUNDAY FOR MOTHERLODE-NORTHEAST  
FOOTHILLS/SACRAMENTO VALLEY-WEST SLOPE NORTHERN SIERRA NEVADA-  
WESTERN PLUMAS COUNTY/LASSEN PARK.  
 

 
 

 
 
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