Area Forecast Discussion
Issued by NWS Reno, NV

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
000
FXUS65 KREV 270530 AAA
AFDREV

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RENO NV
930 PM PST THU FEB 26 2015

.UPDATE...
EVENING SATELLITE IMAGERY SHOWED UPPER LOW MAKING DECENT PROGRESS
SOUTHWARD INTO THE PACNW. A QUICK LOOK AT LATEST MODEL DATA
SUGGESTS THE FORECAST IS ON TRACK WITH THE 00Z GFS AND A NUMBER OF
THE 21Z SREF PLUMES INDICATING A BAND OF SNOW SETTING UP OVER THE
TAHOE BASIN INTO WESTERN NV. THIS FEATURE HAS BEEN RATHER
CONSISTENT THE PAST COUPLE OF DAYS WITH THE MAIN DIFFICULTY
RESIDING IN THE LOCATION OF THIS SNOW BAND ACROSS WESTERN NV. THE
SMALL SCALE FORCING COMBINED WITH UNSTABLE CONDITIONS ARE GOOD
INGREDIENTS FOR SNOWFALL ACCUMULATION DOWN TO VALLEY FLOORS FRIDAY
NIGHT INTO SATURDAY MORNING AND MAY REQUIRE A WINTER WEATHER
HEADLINE FOR PARTS OF WESTERN NV. AGAIN, WE WANT TO STRESS THE
VARIABILITY OF SUCH BANDS AND THAT SNOW AMOUNTS CAN VARY
SIGNIFICANTLY OVER SHORT DISTANCES. SOME MODEL MEMBERS SHOW AS
MUCH AS 5 INCHES OF SNOW IN THE GREATER RENO/CARSON CITY AREAS,
WHILE OTHERS SHOW A DUSTING. BOTTOM LINE, PREPARE FOR HAZARDOUS
DRIVING CONDITIONS FRIDAY NIGHT INTO SATURDAY AND CHECK BOTH
WEATHER AND ROAD CONDITIONS BEFORE TRAVEL. HOHMANN

&&

.PREVIOUS DISCUSSION... /ISSUED 216 PM PST THU FEB 26 2015/

SYNOPSIS...
SOME SHOWERS ARE POSSIBLE TONIGHT NEAR THE OREGON BORDER. THESE
SHOWERS WILL SPREAD SOUTH TO COVER ALL OF NORTHEAST CALIFORNIA AND
WESTERN NEVADA BY FRIDAY NIGHT. ACCUMULATING SNOWS AND DIFFICULT
TRAVEL CONDITIONS ARE LIKELY IN THE SIERRA WITH LIGHTER
ACCUMULATIONS POSSIBLE IN WESTERN NEVADA. THE SNOW WILL SLOWLY
EXIT SUNDAY WITH ANOTHER CHANCE AT SNOW POSSIBLE LATE MONDAY INTO
TUESDAY.

SHORT TERM...
THE UPPER LOW SET TO DROP ALONG THE COAST FROM THE GULF OF ALASKA
IS APPARENT ALONG THE BRITISH COLUMBIA COAST. IT IS THIS FEATURE
THAT IS THE FOCUS OF THE FORECAST INTO THE WEEKEND. THE MODELS
OVERALL ARE IN GOOD AGREEMENT WITH THE TRACK OF THE SYSTEM, BUT
DIFFER ON THE DETAILS AND WITH TIMING TO AN EXTENT.

THE LEADING EDGE OF THE MOISTURE IS INTO SOUTHWEST OREGON RIGHT
NOW WITH SOME LIGHT SHOWERS. THIS WILL SPREAD OVER NORTHEAST
CALIFORNIA AND NORTHWEST NEVADA TONIGHT. SCATTERED SHOWERS ARE
EXPECTED NEAR THE OREGON BORDER WITH IT. THEN AS THE SYSTEM MOVES
SOUTH FRIDAY INTO OREGON IT WILL PUSH A DIFFUSE COLD FRONT THROUGH
THE EASTERN SIERRA AND WESTERN NEVADA.

MOST OF THE MOISTURE IS BEHIND THE FRONT AND THEREFORE EXPECT
SHOWERS TO DEVELOP AFTER ITS PASSAGE. A THUNDERSTORM IS ALSO
POSSIBLE WITH COLDER AIR ALOFT FILTERING IN AS WELL, BUT HAVE LEFT
IT OUT FOR NOW. SOME BANDS OF HEAVIER SHOWERS REMAIN POSSIBLE, BUT
THE EXACT LOCATION DEPENDS ON THE MODEL. OVERALL, THE GFS/EC ARE
IN REASONABLE AGREEMENT WITH THE BEST BANDS DEVELOPING NEAR
RENO/TAHOE LATE FRIDAY NIGHT INTO SATURDAY MORNING. HOWEVER, THE
NAM IS 12 HOURS SLOWER AS IS THE SREF. IT APPEARS THAT THE TAHOE
BASIN WILL AT LEAST SEE SOME SNOW AND HAVE HOISTED A SNOW ADVISORY
FOR LOW END AMOUNTS RIGHT NOW WITH UP TO 1 FOOT ALONG THE CREST
THROUGH SATURDAY. IT COULD BE MORE IF THE BAND DEVELOPS. FOR THE
RENO AREA, THE UNCERTAINTY IS GREATER AND WE ARE LEANING TOWARDS
AN INCH OR LESS. HOWEVER, IF THE BAND FORMS THERE COULD BE 2-4
INCHES ALONG THE SIERRA FRONT. CONFIDENCE IN AMOUNTS IS MODERATE
FOR TAHOE AND LOW EVERYWHERE ELSE.

MONO COUNTY MAY ALSO SEE SOME DECENT SNOWS, BUT THE HEAVIEST SNOW
WILL OCCUR LATER AND MORE SATURDAY INTO SATURDAY NIGHT WITH
UPSLOPE NORTHEAST FLOW. GIVEN THAT IT IS FURTHER OUT THERE, WILL
NOT ISSUE ANYTHING AND CONTINUE TO MONITOR. THUNDERSTORMS ARE ALSO
POSSIBLE SATURDAY AFTERNOON UNDER THE UPPER LOW AS IT MOVES INTO
CENTRAL CALIFORNIA. HAVE ADDED A SLIGHT CHANCE FOR THIS
POSSIBILITY.

THE LOW WILL SLOWLY PULL AWAY SUNDAY, BUT IT IS SLOWER THAN
PREVIOUS RUNS. HAVE HELD ONTO SNOW SHOWERS LONGER INTO SUNDAY AND
ONLY SLOWLY CLEARING MONO COUNTY AS MOIST, NORTHEAST UPSLOPE FLOW
CONTINUES. TEMPERATURES WILL REMAIN BELOW NORMAL SUNDAY AND WILL
FEEL COLDER WITH THE NORTHEAST WINDS. WALLMANN

LONG TERM...MONDAY THROUGH THURSDAY...
RESIDUAL SHOWERS WILL CONTINUE ON MONDAY AS THE LOW PRESSURE
SYSTEM DROPS SOUTH ACROSS SOUTHERN CALIFORNIA. THE NEXT SYSTEM
WILL PUSH INTO THE REGION LATE MONDAY INTO TUESDAY.

VARIABILITY REMAINS HIGH CONCERNING THIS NEXT SLIDER SYSTEM. THE GFS
TRACKS THE SHORTWAVE RIGHT THROUGH NW NEVADA AND NE CALIFORNIA,
BUT THE ECMWF APPEARS TO TAKE THE TRACK FURTHER WEST ALONG THE WEST
COAST. ONE OF THE BIG PLAYERS AFFECTING THE TRACK OF THIS NEXT
SYSTEM IS THE RIDGE ANCHORED AROUND 140W. IF THE RIDGE HOLDS ITS
POSITION FURTHER OFF THE WEST COAST, THEN ANY INCOMING SHORTWAVES
WILL DIVE DOWN THROUGH NV/CA, INCREASING THE PRECIPITATION CHANCES
FOR THE REGION. SLIGHT DEVIATIONS FROM RUN TO RUN MAKE IT DIFFICULT
TO PINPOINT PRECIPITATION CHANCES AT THIS TIME, BUT NEEDLESS TO SAY
THERE IS HIGH CONFIDENCE FOR NORTHERLY FLOW AND COLDER TEMPERATURES
FOR NEXT WEEK.
WEISHAHN

AVIATION...
NORTH WINDS WILL CONTINUE TODAY WITH VFR CONDITIONS FOR ALL
TERMINALS. A WINTER WEATHER SYSTEM WILL MOVE IN FRIDAY, BRINGING
WIDESPREAD CLOUDS, SNOW SHOWERS, ICING, AND POTENTIAL FOR MVFR/IFR
CIG/VIS THROUGH SATURDAY. ACCUMULATING SNOW IS LIKELY FOR
KTRK/KTVL/KMMH WITH EVEN SOME LIGHT ACCUMULATIONS POSSIBLE AT
KRNO/KCXP FRIDAY NIGHT INTO SATURDAY MORNING. HOON/WEISHAHN

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...WINTER WEATHER ADVISORY FROM 4 PM FRIDAY TO 4 PM PST SATURDAY
     NVZ002.

CA...WINTER WEATHER ADVISORY FROM 4 PM FRIDAY TO 4 PM PST SATURDAY
     CAZ072.

&&

$$

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







USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.