Strong Wind in Nevada, April 22, 2014

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RENO NV
948 PM PDT MON APR 21 2014

.UPDATE...
COLD FRONT AND SHOWER BAND WERE MOVING INTO NORTHWEST CALIFORNIA
THIS EVENING AS TROUGH AND ASSOCIATED VORTICITY MAXIMA WERE
RAPIDLY PROGRESSING EASTWARD INTO THE WEST COAST. 00Z GFS/NAM SHOW
ONLY A BRIEF PERIOD OF SHOWERS LATE TONIGHT AND EARLY TUESDAY AS
FRONT SWINGS QUICKLY THROUGH THE REGION AND MOISTURE BECOMES
SHALLOW IN ITS WAKE, ESPECIALLY SOUTH OF I-80. SO SHOWERS ARE
GOING TO BE BRIEF AND VERY LIGHT ALONG THE HIGHWAY 395 CORRIDOR
WITH A FEW INCHES OF SNOW POSSIBLE ABOVE 7000 FEET AS FORECAST,
AND MAINLY FROM EBBETTS PASS NORTHWARD. SO THERE COULD STILL BE
SOME SLICK ROAD CONDITIONS FOR THE TUESDAY MORNING COMMUTE AT THE
PASSES. HAVE BACKED OFF THE POPS A BIT ALONG THE SIERRA FRONT
OVERNIGHT AND THE NIGHT SHIFT WILL ASSESS POTENTIAL FOR LOWERING
POPS BEHIND FRONT ON TUESDAY AS WELL. INSTABILITY INCREASES TUE
AFTERNOON FOR AREAS MAINLY NORTH OF I-80 WHERE SHOWERS WILL
INCREASE AGAIN WITH A LOW POTENTIAL FOR THUNDER. WINDS WERE IN A
LULL THIS EVENING AND HAVE REMOVED THE BLOWING DUST. HOWEVER WINDS
WILL INCREASE RIGHT AHEAD OF THE FRONT LATE TONIGHT, DIMINISH
BRIEFLY BEHIND FRONT IN THE MORNING AND THEN INCREASE AGAIN IN THE
AFTERNOON AS THE THERMAL GRADIENT TIGHTENS. HOHMANN

&&

.PREVIOUS DISCUSSION... /ISSUED 223 PM PDT MON APR 21 2014/

SYNOPSIS...

GUSTY WINDS WILL CONTINUE THROUGH TONIGHT AHEAD OF A STRONG COLD
FRONT. HIGHS ON TUESDAY WILL BE 20 TO 25 DEGREES COOLER THAN
TODAY. THERE ARE CHANCES FOR RAIN AND SNOW TONIGHT INTO TUESDAY
WITH LIGHT SNOW ACCUMULATIONS POSSIBLE ABOVE 7000 FEET IN THE
SIERRA. A BREAK IS EXPECTED WEDNESDAY AND THURSDAY BEFORE A COLD
AND WETTER STORM ARRIVES BY FRIDAY.

SHORT TERM...

HIGH CLOUDS HAVE MOVED OVER THE SIERRA AND WESTERN NEVADA THIS
AFTERNOON AHEAD OF A FAST MOVING SPRING STORM THAT WILL IMPACT THE
REGION TONIGHT INTO TUESDAY. THE MAIN IMPACTS WITH THIS SYSTEM
WILL BE GUSTY WINDS TONIGHT...A FEW INCHES OF SNOW IN THE SIERRA
ABOVE 7000 FEET EARLY TUESDAY MORNING AND MUCH COLDER
TEMPERATURES ON TUESDAY.

WINDS...WINDS WILL CONTINUE TO INCREASE THIS AFTERNOON AND
EVENING AHEAD OF A STRONG COLD FRONT. THE STRONGEST WINDS ARE
EXPECTED LATE TONIGHT (BETWEEN MIDNIGHT AND 5 AM), WITH MOST VALLEY
LOCATIONS ACROSS WESTERN NEVADA SEEING GUSTS UP TO 40 MPH. HIGHER
GUSTS OF 50-60 MPH ARE POSSIBLE IN WIND PRONE AREAS SUCH AS GALENA
AND WASHOE VALLEY. THE WINDS WILL MAINLY BE GRADIENT
DRIVEN...HOWEVER CROSS SECTIONS FROM THE 12Z NAM DO SHOW A BRIEF
PERIOD OF WEAK DUCTING LATE TONIGHT WHICH COULD ENHANCE THE
DOWNSLOPE COMPONENT FOR A FEW HOURS. WINDS WILL REMAIN BREEZY ON
TUESDAY AS A STRONG WEST TO EAST PRESSURE GRADIENT DEVELOPS
BETWEEN THE SIERRA AND STRENGTHENING LOW PRESSURE OVER UTAH. LAKE
WIND ADVISORIES REMAIN IN EFFECT FOR TAHOE AND PYRAMID THROUGH
TUESDAY AFTERNOON.

PRECIP...A BAND OF SHOWERS WILL FOLLOW THE COLD FRONT AS IT MOVES
ACROSS THE SIERRA AND WESTERN NEVADA EARLY TUESDAY MORNING. A
QUICK 1-3 INCHES OF SNOW ARE POSSIBLE IN THE SIERRA ABOVE 7000
FEET. SNOW LEVELS WILL RAPIDLY FALL TO AROUND 5000 FEET BEHIND
THE FRONT...HOWEVER LITTLE IN THE WAY OF ACCUMULATIONS ARE
EXPECTED BELOW 7000 FEET GIVEN THE RECENT WARM SPELL AND HIGH SUN
ANGLE FOR LATE APRIL. THE SHOWERS WILL BECOME MORE ISOLATED
BY TUESDAY AFTERNOON. MAINTAINED MENTION OF THUNDER FOR AREAS
NORTH OF INTERSTATE 80 ON TUESDAY AFTERNOON AS BOTH THE 12Z GFS
AND NAM SHOW SOME WEAK INSTABILITY IN THIS REGION UNDER THE COLD
CORE OF THE TROUGH.

TEMPERATURES...DAYTIME TEMPS ARE FORECAST TO BE 20 TO 25 DEGREES
COOLER ON TUESDAY THAN TODAY WITH HIGHS IN THE MID 50S ACROSS
WESTERN NEVADA VALLEYS AND MID 40S NEAR LAKE TAHOE. BREEZY WINDS
DURING THE DAY ON TUESDAY WILL MAKE IT FEEL EVEN COLDER. WEDNESDAY
MORNING WILL BE CHILLY COMPARED TO RECENT MORNINGS...WITH LOWS AT
OR JUST BELOW FREEZING ACROSS MOST WESTERN NEVADA VALLEYS. ANYONE
WITH SENSITIVE PLANTS SHOULD CONSIDER MOVING THEM INSIDE TUESDAY
NIGHT.

A SHORTWAVE RIDGE OF HIGH PRESSURE WILL MOVE OVER NORTHERN
CALIFORNIA AND NEVADA MIDWEEK WITH HIGH TEMPERATURES RETURNING TO
SEASONAL NORMS ON WEDNESDAY AND THURSDAY. MYRICK

LONG TERM...THURSDAY NIGHT THROUGH MONDAY...

LATE SEASON STORM IS ON TRACK TO BRING RAIN AND SNOW TO MUCH OF THE
REGION THURSDAY NIGHT THROUGH FRIDAY NIGHT. NEXT WEEKEND STILL LOOKS
UNSETTLED WITH BELOW NORMAL TEMPS AND LIGHT SHOWERS CONTINUING,
BEFORE DRY AND WARMER CONDITIONS RETURN EARLY NEXT WEEK. OVERALL
FORECAST CONFIDENCE IS MEDIUM AS GUIDANCE DATA IS IN GOOD AGREEMENT
WITH THE FRIDAY STORM AND AGAIN WITH THE RIDGE NEXT MONDAY, BUT
SOMEWHAT UNCERTAIN WITH THE DETAILS OF THE WEATHER PATTERN FOR THE
WEEKEND.

ONGOING LIGHT RAIN AND HIGH ELEVATION SNOW THURSDAY NORTH OF
SUSANVILLE-GERLACH WILL SPREAD SOUTH ALONG THE SIERRA AND INTO MUCH
OF WESTERN NV NORTH OF HIGHWAY 50 THURSDAY NIGHT. OVERALL THE BEST
CHANCE FOR PRECIP WILL BE ON FRIDAY AS THE TROUGH AND SURFACE COLD
FRONT MOVE ACROSS THE REGION. THIS SYSTEM SHOULD CONTAIN A DECENT
PACIFIC MOISTURE TAP AND UPPER LEVEL JET SUPPORT, WITH INSTABILITY
SUFFICIENT TO PRODUCE A PERIOD OF SPILLOVER PRECIP INTO WESTERN NV
ALONG AND BEHIND THE COLD FRONT PASSAGE. SHOWERS WILL CONTINUE
CONTINUE FRIDAY EVENING ESPECIALLY IN THE SIERRA, WITH COVERAGE
GRADUALLY DIMINISHING OVERNIGHT. A PERIOD OF GUSTY WINDS IS ALSO
LIKELY WITH THIS EVENT, ALTHOUGH SPEEDS SHOULD TO BE LOWER COMPARED
TO TONIGHT AND TUESDAY.

SNOW LEVELS ARE ON TRACK TO FALL BELOW 7000 FEET BY EARLY FRIDAY
MORNING FROM RENO-TAHOE NORTHWARD, THEN AS LOW AS 5000-5500 FEET BY
FRIDAY EVENING. EVEN DURING THE DAY FRIDAY, SNOW IS PROBABLE DOWN TO
LAKE LEVEL, ALTHOUGH SNOW ACCUMULATIONS BELOW 7000 FEET WILL BE
LIMITED DUE TO HIGH SUN ANGLES FOR LATE APRIL. SOUTH OF TAHOE, SNOW
LEVELS ARE MORE LIKELY TO DROP BELOW 7000 FEET BY LATE AFTERNOON OR
EARLY EVENING. QPF VALUES ALONG THE SIERRA ARE STILL APPROACHING 1
INCH, WHICH WOULD LEAD TO POTENTIAL SNOWFALL NEAR 1 FOOT ABOVE 7000
FEET. FOR WESTERN NV, RAINFALL AROUND 0.10 INCH IS POSSIBLE WITH
LOCALLY HIGHER AMOUNTS NEAR 0.25 INCH. IF WRAP AROUND BANDS OF
SHOWERS FORM FRIDAY NIGHT AS THE LOW MOVES INTO THE GREAT BASIN,
SOME LOCATIONS WOULD RECEIVE HIGHER PRECIP TOTALS.

FOR NEXT WEEKEND, DIFFERENCES ARISE AMONG THE MEDIUM RANGE GUIDANCE.
SOME SCENARIOS SLOW DOWN THE UPPER LOW AS IT REACHES THE SOUTHERN
ROCKIES AND BUILD UP A RIDGE MORE QUICKLY OVER THE WEST. OTHERS ARE
MORE PROGRESSIVE AND KEEP ZONAL FLOW OVER THE WEST, WITH ANOTHER
SHORTWAVE PASSAGE ACROSS NORTHERN CA-NV SATURDAY NIGHT OR EARLY
SUNDAY. DUE TO THESE DIFFERENCES, WE WILL KEEP A MENTION OF LIGHT
RAIN AND SNOW SHOWERS IN PLACE THROUGH THE WEEKEND. DAYTIME TEMPS ON
SATURDAY WILL ONLY REACH THE LOWER TO MID 50S IN WESTERN NV AND 40S
FOR THE SIERRA VALLEYS, FOLLOWED BY SLIGHT WARMING ON SUNDAY.

BY NEXT MONDAY, MOST GUIDANCE RETURNS TO BETTER AGREEMENT WITH RIDGE
REBUILDING NEAR THE WEST COAST. THIS WILL BRING DRY WEATHER AND A
MORE SIGNIFICANT WARMING TREND, WITH HIGHS REBOUNDING INTO THE LOWER
70S FOR MUCH OF WESTERN NV. MJD

AVIATION...

GUSTY SOUTHWEST WINDS AND MOUNTAIN WAVES WITH SFC GUSTS TO 35-45 KT
ARE EXPECTED AT TIMES THROUGH TUESDAY MORNING. BEHIND THE FRONT
BRISK WEST-NORTHWEST GRADIENT WINDS SUSTAINED 15-20 KT WITH GUSTS
25-35 KT WILL PERSIST THROUGH TUESDAY EVENING.

RAIN AND SNOW WILL REACH THE TAHOE AREA TERMINALS AFTER 06Z TONIGHT
WITH MVFR TO IFR CONDITIONS POSSIBLE. ANY SNOW THAT DOES OCCUR WILL
PROBABLY NOT ACCUMULATE ON RUNWAYS/TARMACS DUE TO THE RECENT WARM
WEATHER. HOWEVER LIGHT ACCUMULATIONS ARE POSSIBLE ON ELEVATED
SURFACES. FARTHER SOUTH, SNOW POTENTIAL IS LOWER AT KMMH DUE TO
STRONGER SHADOWING, ALTHOUGH MOUNTAIN OBSCURATIONS ARE LIKELY WEST
OF THE AIRPORT. FOR WESTERN NEVADA...BEST CHANCE FOR RAIN IS TUESDAY
BEHIND THE FRONT WITH SHORT PERIODS OF MVFR CEILINGS POSSIBLE.
BRONG/MJD

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...LAKE WIND ADVISORY FROM 11 AM TO 6 PM PDT TUESDAY FOR PYRAMID
     LAKE IN NVZ004.

     LAKE WIND ADVISORY UNTIL 6 PM PDT TUESDAY FOR LAKE TAHOE IN
     NVZ002.

CA...LAKE WIND ADVISORY UNTIL 6 PM PDT TUESDAY FOR LAKE TAHOE IN
     CAZ072.

&&

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