NATIONAL WEATHER SERVICE FORECAST DISCUSSION
Area Forecast Discussion
Issued by The National Weather Service
Current Report   Previous reports > 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
Note: Links in the text will open a (small) new browser window with more information inside.




000
FXUS66 KSTO 182303
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
303 PM PST Sun Feb 18 2018


.SYNOPSIS  
A COLD WEATHER SYSTEM BRINGS BREEZY WINDS AND SNOW OVER THE MOUNTAINS AND FOOTHILLS INTO MONDAY, IMPACTING TRAVEL. THIS WILL BE FOLLOWED BY NEAR RECORD COLD TEMPERATURES WITH A POSSIBLE WIDESPREAD FREEZE.
.DISCUSSION  SCATTERED SHOWERS ARE SPREADING ACROSS THE MOUNTAINS, WITH THE HEAVIEST SHOWERS CURRENTLY OVER THE NORTHERN SIERRA NORTH OF HIGHWAY 50. WEBCAMS ON I80 SHOW MODERATE TO HEAVY SNOW SHOWERS. SNOW SHOWERS OVER THE SIERRA ARE EXPECTED TO BRING SLIPPERY ROADS AND TRAVEL DELAYS. A WINTER WEATHER ADVISORY CONTINUES TO BE IN EFFECT UNTIL 4 PM MONDAY. USE CAUTION IF TRAVELING IN THE MOUNTAINS AND UPPER FOOTHILLS. A DUSTING OF SNOW WILL BE POSSIBLE ACROSS THE FOOTHILLS OVERNIGHT INTO MONDAY. SNOW ACCUMULATIONS ARE NOT EXPECTED TO BE IMPRESSIVE, BUT THIS HOLIDAY WEEKEND TRADITIONALLY SEES A HIGH VOLUME OF TRAFFIC OVER THE MOUNTAINS AND SNOW COULD CAUSE EXACERBATED IMPACTS. WHAT WILL LIKELY BE THE COLDEST AIR OF THE WINTER SEASON WILL BEGIN TO IMPACT PORTIONS OF THE REGION TONIGHT. FOR LOWER ELEVATIONS, THE COLDEST TEMPERATURES TONIGHT WILL LIKELY BE ACROSS THE NORTHERN VALLEY, WHERE SKIES CLEAR AND WINDS SLACKEN. SKIES SHOULD CLEAR FURTHER MONDAY NIGHT INTO TUESDAY MORNING, AND CURRENTLY APPEARS TO BE THE COLDEST NIGHT OF THIS EVENT. WIDESPREAD FREEZE CONDITIONS MAY CONTINUE TUESDAY NIGHT. WIDESPREAD FROST IS EXPECTED. AGRICULTURAL IMPACTS COULD BE SIGNIFICANT, DUE TO AN EARLY BLOOM FROM UNUSUALLY MILD WEATHER IN RECENT WEEKS. PEOPLE SHOULD BEGIN PLANNING NOW ON WAYS TO PROTECT SENSITIVE PLANTS, OUTDOOR PETS, AND OUTDOOR PIPES. ANOTHER SYSTEM WILL BRING LIGHT SNOW SHOWERS TO THE MOUNTAINS ON WEDNESDAY. SNOW LEVELS WILL BE AROUND 1000 FEET, POSSIBLY LOWER, BUT JUST A DUSTING OF SNOW IS EXPECTED.
.EXTENDED DISCUSSION  (Thursday THROUGH Sunday)   A series of cold shortwave troughs will pass through NorCal for the extended period. Models are more aligned today with timing and placement. The first system arrives Wednesday night into Thursday and will bring precip chances for both the Valley and higher elevations. The best chances for Valley showers will be Thursday afternoon when some weak instability builds in and the trough axis swings through. With not a ton of moisture to work with, precip totals should remain rather low. Low snow levels will be a concern though as they will be 1000 to 2500 feet. Hazardous Mountain travel will be possible Thursday lasting into Friday morning. A weak ridge builds in Friday into early Saturday with another short wave trough passing just to our east on Saturday. This will bring the chances for light showers mainly to the northern Mountains. Another system arrives Sunday into Monday. The EC is just a bit further to the west with it and is able to pull in higher moisture levels but the GFS is drier. Cool temperatures will remain in place for the period running 5-10 below normal to start but will gradually warm a few degrees each day. -CJM
.AVIATION 
Generally VFR conditions are expected at the TAF sites the next 24 hours. SCT to BKN clouds between 5000 and 10000 feet can be expected this afternoon rising to around 10000 feet overnight. Scattered snow showers continue in the higher elevations through 15z Monday and MVFR/IFR conditions can be expected in any showers. Breezy northerly winds 15-30 knots diminish to 5-11 knots overnight. -CJM
.STO   WATCHES/WARNINGS/ADVISORIES    
Winter Weather Advisory until 4 PM PST Monday for West Slope Northern Sierra Nevada. Freeze Warning from 2 AM Monday to 8 AM PST Wednesday for Carquinez Strait and Delta-Central Sacramento Valley-Clear Lake/Southern Lake County-Motherlode-Northeast Foothills/Sacramento Valley-Northern Sacramento Valley-Northern San Joaquin Valley-Shasta Lake Area / Northern Shasta County- Southern Sacramento Valley.
powered by Cumulus v1.9.3 (1059)
Ambient Weather VWS v14.00
Top Contact Website Map Copyright © 2007 - 2018 Foresthillweather.com Never base important decisions on this or any weather information obtained from the Internet