Heavy Snow and Winter Weather in Nevada, February 27 to 28, 2015

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
224 PM PST FRI FEB 27 2015

.SYNOPSIS...
SNOW SHOWERS ASSOCIATED WITH A WINTER SYSTEM WILL CONTINUE THROUGH
THE WEEKEND. ACCUMULATING SNOW AND DIFFICULT TRAVEL ARE LIKELY IN
THE SIERRA WITH LIGHTER AMOUNTS AND MORE LOCALIZED TRAVEL ISSUES
IN WESTERN NEVADA. THIS SYSTEM WILL EXIT SUNDAY WITH A WEAKER
SYSTEM EXPECTED MONDAY AFTERNOON KEEPING TEMPERATURES BELOW
NORMAL. DRY CONDITIONS AND A WARMING TREND ARE EXPECTED LATER NEXT
WEEK.

&&

.SHORT TERM...
MAIN CONCERN CONTINUES TO BE THE NEXT 24 HOURS AS THE UPPER LOW
NEAR THE MOUTH OF THE COLUMBIA RIVER TREKS SOUTHWARD INTO CENTRAL
CALIFORNIA. NUMEROUS SHOWERS ARE OCCURRING OVER NORTHEAST
CALIFORNIA AND NORTHWEST NEVADA THIS AFTERNOON AND WILL CONTINUE
INTO THE EVENING. ISOLATED THUNDERSTORMS REMAIN POSSIBLE.

THEN, AS THE UPPER LOW MOVES INTO NORTHERN CALIFORNIA TONIGHT,
GFS/NAM/EC ALL HINT AT A BAND OF SNOW FORMING IN THE DEFORMATION
ON THE EAST SIDE OF THE LOW. THE LOCATION REMAINS IN QUESTION, BUT
THE MOST LIKELY LOCATION CONTINUES TO BE HIGHWAY 50 SOUTHWARD INTO
NORTHERN MONO COUNTY. HAVE MADE FEW CHANGES FROM PREVIOUS FCST
UPDATE. STILL EXPECT A ROUGH 1-2 INCHES FOR THE SIERRA FRONT WITH
2-5 INCHES IN THE TAHOE BASIN OUTSIDE THIS BAND WITH DOUBLE THE
AMOUNTS OR MORE IN THIS BAND.

AWAY FROM RENO/TAHOE, EXPECT THE NUMEROUS SHOWERS TO CONTINUE AND
ACCUMULATIONS TO BE MORE LOCALIZED. A QUICK INCH OR SO OF SNOW IS
POSSIBLE IN ANY SHOWER WITH PELLETS. THESE ALONE COULD CREATE
TRAVEL HEADACHES AS ONE GOES FROM NEAR DRY PAVEMENT TO A VERY
SLICK ROAD WITH ICE PELLETS WITHIN A FEW HUNDRED FEET. THE SHOWERS
WILL CONTINUE OVERNIGHT ALONG WITH THE THREAT FOR SLICK ROADS

EXPECT THE THREAT FOR THE HEAVIEST SNOW TO WIND DOWN TOMORROW
MORNING AS THE LOW CONTINUES SOUTH. HOWEVER, IT WILL REMAIN
UNSTABLE ACROSS THE REGION AND SCATTERED TO NUMEROUS SHOWERS WILL
OCCUR AGAIN. WHILE THE ROADS SHOULD WARM ENOUGH TO PREVENT MOST
ACCUMULATION, INTENSE PELLET SHOWERS COULD CREATE THE SAME TRAVEL
ISSUES SEEN THIS EVENING IN LOCALIZED SPOTS.

SATURDAY AFTERNOON COULD SEE A BIT STEADIER SNOW IN MONO COUNTY
WITH NORTHEAST UPSLOPE FLOW AS WELL. HOWEVER, BELIEVE THE DAYTIME
INSOLATION WILL KEEP ROAD ISSUES MINOR AND THE HEAVIEST
ACCUMULATIONS OCCURRING RIGHT NEAR THE CREST PRECLUDE ANY
HIGHLIGHTS AT THIS TIME.

THE LOW CONTINUES TO PULL AWAY SATURDAY NIGHT INTO SUNDAY WITH
SHOWERS DIMINISHING FROM NORTH TO SOUTH. MONO COUNTY WILL SEE THE
GREATEST THREAT FOR ACCUMULATIONS DURING THIS TIME WITH THE
UPSLOPE FLOW, ESPECIALLY SATURDAY NIGHT. TEMPERATURES WILL REMAIN
BELOW NORMAL, BUT GRADUAL CLEARING AND LESS WIND WILL MAKE IT FEEL
WARMER THAN SATURDAY. WALLMANN

.LONG TERM...MONDAY THROUGH FRIDAY...
FOR EARLY NEXT WEEK, MEDIUM RANGE GUIDANCE HAS TRENDED FASTER
WITH SHORTWAVE DIVING SOUTH NEAR THE WEST COAST DURING THE DAY
MONDAY, WITH MORE OF A SPLIT FLOW ACROSS THE WESTERN US. THIS
PATTERN WOULD BE LESS FAVORABLE FOR BRINGING MUCH ORGANIZED PRECIP
TO THE SIERRA OR WESTERN NV, WITH MAYBE A SHORT ROUND OF SHOWERS
MONDAY OR MONDAY NIGHT, THEN DRYING QUICKLY BY TUESDAY. PREVIOUS
ECMWF RUNS WERE MORE AGGRESSIVE WITH PRECIP POTENTIAL ACROSS THE
REGION, BUT THE 12Z RUN TRENDED TOWARD THE DRIER GFS SCENARIO. AS
A RESULT, WE LOWERED POPS MONDAY NIGHT WITH CHANCE POPS RETAINED
ONLY FOR THE TAHOE-MONO ZONES AND SOUTHERN MINERAL COUNTY. ON
TUESDAY, PRECIP WAS REMOVED NORTH OF HIGHWAY 50, WITH ONLY SLIGHT
CHANCES SOUTH OF HIGHWAY 50.

WHILE TEMPS MONDAY AND TUESDAY ARE STILL LIKELY TO REMAIN BELOW
NORMAL, THE COLDEST AIR APPEARS TO PUSH FARTHER EAST ACROSS THE
ROCKIES AND GREAT PLAINS. SO EVEN IF PRECIP DOES DEVELOP, IT MAY END
UP AS RAIN OR A RAIN-SNOW MIX BELOW 5000 FEET. ALSO WITH THE MAIN
TROUGH PUSHING EAST SOONER AND THE STRONGER NORTH FLOW MORE LIKELY
TO SET UP ACROSS THE EASTERN GREAT BASIN, POTENTIAL IS REDUCED FOR
GUSTY NORTHEAST RIDGE WINDS OVER THE SIERRA FROM TUESDAY NIGHT INTO
EARLY WEDNESDAY.

FROM WEDNESDAY THROUGH FRIDAY, GUIDANCE IS IN GENERALLY GOOD
AGREEMENT WITH RIDGE REBUILDING INLAND ACROSS THE GREAT BASIN,
RESULTING IN DRY CONDITIONS AND A GRADUAL WARMING TREND. TEMPS
COULD RETURN TO ABOVE NORMAL AS SOON AS THURSDAY, BUT MORE LIKELY BY
FRIDAY AS HIGHS APPROACH 60 DEGREES IN WESTERN NV. THERE COULD BE A
WEAK SHORTWAVE PASSAGE TOWARD THE END OF NEXT WEEK BUT IT IS
UNLIKELY TO PRODUCE MUCH MORE THAN AREAS OF HIGH CLOUDS. MJD

&&

.AVIATION...
SCATTERED-NUMEROUS SHOWERS THRU 04Z THIS EVENING WILL BRING MVFR
CIGS/VIS AT TIMES MAINLY AT KTRK/KTVL WHERE PRECIP TYPE IS MORE
LIKELY TO BE SNOW. FOR WESTERN NV, SHOWERS ARE MORE LIKELY TO
PRODUCE RAIN OR GRAUPEL WHICH WILL HAVE LESS IMPACT ON CIGS/VIS
BUT COULD PRODUCE ICING CONCERNS. WIND GUSTS 25-30 KT ARE ALSO
EXPECTED AT AREA TERMINALS THRU EARLY EVENING.

LATER TONIGHT AND INTO SAT AM, GENERALLY BETWEEN 04-18Z IN THE TAHOE
BASIN AND 09-18Z FOR FAR WESTERN NV, BANDS OF SNOW ARE LIKELY TO
DEVELOP WITH CONDS WORSENING TO IFR/LIFR AND SNOW ACCUMULATIONS ON
RUNWAYS. CURRENTLY EXPECTING 1-2 INCHES OF SNOW AT KRNO/KCXP, WITH
2-4 INCHES AT KTRK/KTVL. IF A HEAVIER SNOW BAND SETS UP, AND
PERSISTS OVER ANY TERMINALS THESE AMOUNTS COULD BE MUCH HIGHER. SNOW
SHOWERS WILL CONTINUE THRU THE REMAINDER OF SATURDAY AFTN-EVE WITH
LOCAL IFR CONDS STILL POSSIBLE.

FOR KMMH, SCT -SHSN WILL PRODUCE SOME MVFR CIGS/VIS WITH MTN
OBSCURATIONS TONIGHT, BUT MORE SIGNIFICANT IMPACTS DUE TO SNOW ARE
LIKELY TO OCCUR SATURDAY AFTERNOON AND EVENING WHEN MOIST UPSLOPE
FLOW COULD PRODUCE SOME BANDS OF HEAVIER SNOW. MJD

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...WINTER WEATHER ADVISORY UNTIL 4 PM PST SATURDAY NVZ002.

     WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 10 AM PST
     SATURDAY NVZ003.

CA...WINTER WEATHER ADVISORY UNTIL 4 PM PST SATURDAY CAZ072.

&&

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