718
FXUS65 KREV 111943
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
1243 PM PDT SUN APR 11 2021
SYNOPSIS
IT WILL REMAIN WARM AND DRY THROUGH MONDAY WITH GENERALLY LIGHT
WINDS. WINDS WILL INCREASE, BECOMING GUSTY SOUTH OF US-50,
TUESDAY AS A COLDER SYSTEM DROPS INTO THE REGION. THIS SYSTEM WILL
BRING COLDER TEMPERATURES ALONG WITH CHANCES FOR SHOWERS, THOUGH
IT DOES NOT LOOK TO BE A MAJOR PRECIPITATION PRODUCER. SIMULATIONS
FAVOR WARMER AND DRIER CONDITIONS BY THE FOLLOWING WEEKEND.
DISCUSSION
ANOTHER DRY AND SEASONABLY WARM DAY WITH AFTERNOON HIGHS EXPECTED
TO PEAK 5-8 DEGREES ABOVE AVERAGE AS A HIGH PRESSURE RIDGE SITS
OFF THE WEST COAST. SIMILAR CONDITIONS ARE FORECAST FOR MONDAY
WITH LIGHT EAST-NORTHEASTERLY FLOW IN PLACE AS WINDS SHIFT TO THE
SOUTHWEST ALONG THE EASTERN SIERRA. SOME CUMULUS BUILD-UPS ARE
POSSIBLE MONDAY AFTERNOON ALONG THE SIERRA CREST AND INTO THE
TAHOE BASIN, HOWEVER CHANCES FOR AN ISOLATED THUNDERSTORM TO
DEVELOP REMAIN LOW (5-10%).
THE WEATHER PATTERN BEGINS TO CHANGE LATE MONDAY NIGHT THROUGH
WEDNESDAY AS AN UPPER-LEVEL LOW PRESSURE SYSTEM DROPS SOUTHWARD
OVER THE REGION FROM THE PACIFIC NORTHWEST.
TEMPERATURES: CONFIDENCE REMAINS HIGH IN COOLER TEMPERATURES FOR
TUESDAY AND WEDNESDAY WITH HIGHS A FEW DEGREES BELOW AVERAGE FOR
MID-APRIL. GFS 700 MB TEMPERATURES ARE BETWEEN -7 AND -5 DEGREES
CELSIUS WEDNESDAY AFTERNOON (THE CHILLIEST DAY OF THIS WEEK) WHICH
WOULD TRANSLATE TO SURFACE TEMPERATURES IN THE MID TO UPPER 50S
REGION-WIDE, OF COURSE ABOUT 5-10 DEGREES COOLER IN THE
MOUNTAINS. A WARMING TREND LOOKS TO BEGIN ON THURSDAY WITH A
RETURN TO ABOVE AVERAGE TEMPERATURES FOR THE WEEKEND.
PRECIPITATION: NOT MUCH CHANGE TO OUR OVERALL THINKING REGARDING
PRECIPITATION WITH THIS SYSTEM. EVEN THOUGH MEDIUM CONFIDENCE
EXISTS IN SCATTERED CHANCE POPS (25-40%) FOR TUESDAY INTO
WEDNESDAY, QPF REMAINS LOW AT THIS TIME AND TO BE HONEST WILL
PROBABLY REMAIN LOW WITH THIS STORM GIVEN ITS DIFFICULT FORECAST
NATURE. CUT-OFF, SPRING TIME LOWS WITH A LIMITED MOISTURE SOURCE
MOST OF THE TIME RESULT IN MOSTLY CLOUDY SKIES WITH ISOLATED TO
SCATTERED RAIN/HIGH ELEVATION SNOW SHOWERS ACROSS MOST OF THE
REGION. PELLET SHOWERS AND A RUMBLE OF THUNDER ARE ALSO ON THE
TABLE DURING THE AFTERNOON HOURS AS THE COLD POOL OF THE LOW SITS
OVERHEAD COUPLED WITH SOME DAYTIME SURFACE HEATING LEADING TO
UNSTABLE CONDITIONS. CURRENT NBM TOTAL QPF PROJECTIONS SHOW A ~15%
CHANCE FOR 0.10" FOR RENO AND SOUTH LAKE TAHOE WITH A 25% CHANCE
OF AN INCH OR TWO OF SNOW FOR THE SIERRA CREST BY WEDNESDAY
EVENING.
WINDS: MOST LIKELY THE MAIN IMPACT, WITH CONFIDENCE INCREASING,
IS THE POTENTIAL FOR GUSTY SOUTHWEST WINDS AND AN ELEVATED FIRE
RISK FOR MONO AND MINERAL COUNTIES FOR TUESDAY AFTERNOON. ENHANCED
NORTH TO NORTHWEST WINDS ARE FORECAST FROM US-50 NORTHWARD WITH
GUSTS OF 25-35 MPH RESULTING IN PROBABLE BLOWING DUST IN THE BASIN
AND RANGE AND ROUGH CONDITIONS ON AREA LAKES. THE MAIN CONCERN IS
FOR LOCATIONS SOUTH OF US-50 WHERE THE STRONGEST WIND GUSTS ARE
ANTICIPATED AS THE SYSTEM'S FRONT PUSHES THROUGH TUESDAY
AFTERNOON/EVENING. MULTIPLE FORECASTING TOOLS THIS MORNING,
INCLUDING THE ECMWF GUST ENSEMBLE, THE ICON, AND NBM, ALL SHOW
GUSTS IN THE 40-50 MPH RANGE FROM 2 PM - 8 PM TIMEFRAME ON
TUESDAY. HIGHER GUSTS ARE POSSIBLE ALONG THE SIERRA RIDGES AND FOR
WIND PRONE LOCATIONS ON US-395 SUCH AS BRIDGEPORT, WALKER, AND
LUNDY. EVEN THE ECMWF EXTREME FORECAST INDEX (EFI) HIGHLIGHTS
SOUTHERN ALPINE AND MONO COUNTY WITH ABOVE AVERAGE WIND GUSTS
DURING THIS TIME PERIOD FOR THIS TIME OF YEAR. SYNOPTICALLY
SPEAKING, THIS POTENTIAL OUTCOME MAKES SENSE GIVEN THE UPPER-
LEVEL JET SUPPORT ACCOMPANYING THE FRONTAL PASSAGE TAKING PLACE
DURING PEAK MIXING TIME. THESE STRONG WINDS COUPLED WITH A BRIEF,
PRE-FRONTAL PERIOD OF LOW HUMIDITY (15% OR BELOW) HAS INCREASED
OUR CONFIDENCE IN AN ELEVATED FIRE RISK FOR MONO AND MINERAL
COUNTIES. FOR MORE INFORMATION, PLEASE SEE THE FIRE WEATHER
DISCUSSION BELOW.
AS FOR THE REMAINDER OF THE FORECAST FROM THURSDAY INTO NEXT
WEEKEND, LIGHTER NORTH-NORTHEASTERLY WINDS AND IMPROVING
CONDITIONS WITH A WARMING TREND IS LIKELY. WE COULD SEE A FEW WEAK
WAVES PUSH THROUGH THE REGION FRIDAY AND AGAIN SATURDAY INTO
SUNDAY FROM THE NORTHEAST AS THE LOW PRESSURE SYSTEM EXITS SLOWLY
TOWARDS THE EAST WITH RIDGING BUILDING IN THEREAFTER FROM THE WEST.
-LAGUARDIA
AVIATION
VFR CONDITIONS REMAIN THROUGH MONDAY WITH LIGHT EASTERLY FLOW AT
THE SURFACE AND SOME HIGH CLOUDS. COULD SEE SOME CUMULUS BUILD-UPS
ALONG THE SIERRA AND AROUND THE TAHOE BASIN MONDAY LATE
AFTERNOON/EVENING, BUT THE CHANCE FOR AN ISOLATED THUNDERSTORM TO
DEVELOP REMAINS LOW (~5-10%).
CONDITIONS BEGIN TO DETERIORATE ACROSS THE REGION LATE MONDAY
NIGHT INTO TUESDAY AS A LOW PRESSURE SYSTEM DROPS FROM THE NORTH.
MAIN IMPACTS TO AREA TERMINALS WILL BE GUSTY WINDS, PERIODS OF
LLWS, AND SOME TURBULENCE AS THE SYSTEM'S FRONT PUSHES THROUGH
TUESDAY AFTERNOON/EVENING. NORTH TO NORTHWEST WINDS WILL BE
ENHANCED FOR TERMINALS NORTH OF US-50 (KSVE-KTRK-KRTS-KRNO-KCXP-
KLOL-NFL) WITH GUSTS 25-30 KTS POSSIBLE DURING THIS TIME. THE
STRONGEST GUSTS FROM THE SOUTHWEST ARE EXPECTED TO TAKE PLACE FOR
AREAS SOUTH OF US-50, INCLUDING KMMH AND KHTH, WITH GUSTS 30-45
KTS POSSIBLE.
WITH THE INCREASED WINDS TUESDAY AFTERNOON, BLOWING DUST IS
LIKELY IN THE NEVADA BASIN AND RANGE. WE COULD SEE SHOWERS ON
TUESDAY INTO WEDNESDAY AS WELL, BUT THIS WILL BE MORE HIT OR MISS.
THESE SHOWERS COULD BRING SOME AREAS OF TERRAIN OBSCURATION.
-LAGUARDIA
FIRE WEATHER
TODAY IS OUR FIRST DAY OF 2X/DAY FIRE WEATHER FORECASTS, WHICH MEANS
WE ARE IN "HIGH SEASON" FOR FIRE WEATHER. THIS MEANS YOU WILL SEE
UPDATED AFTERNOON FIRE WEATHER PLANNING FORECASTS (FWF) AND ECCDA
(FWL) DISCUSSIONS EACH DAY.
WE AREN'T THE FUELS EXPERTS, BUT FROM THE INTEL THAT WE HAVE
RECEIVED THIS IS WHAT WE KNOW:
GREEN UP HAS BARELY BEGUN ACROSS THE AREA, SO MANY LOCATIONS ARE
STILL CAPABLE OF BURNING, ESPECIALLY FOOTHILLS AND VALLEYS BELOW
5500 FEET. MULTIPLE SITES AROUND THE EASTERN SIERRA AND WESTERN
NEVADA ARE AT "PEAK FIRE SEASON" VALUES. PARTNERS IN THE SOUTHERN
SIERRA FRONT HAVE REPORTED THAT LIVE FUEL MOISTURES ARE 103%/108%.
VALUES BELOW 125% ARE CONSIDERED CRITICAL. THERE IS A LACK OF
GRASS CROP ACROSS THE LOWER ELEVATIONS, SO WE HAVE THAT GOING FOR
US.
TUESDAY IN THE LOWER EASTERN SIERRA WILL BE THE PRIMARY FIRE CONCERN
TIME/LOCATION THIS WEEK. A LOW PRESSURE SYSTEM WILL DROP THROUGH THE
GREAT BASIN TUESDAY/WEDNESDAY WHICH WILL BRING A NOTABLE COOLDOWN IN
TEMPERATURES, INCREASED HUMIDITY, AND SOME CHANCES FOR SHOWERS.
UNLIKELY TO BE A WETTING RAIN, BUT THERE WILL BE SOME SHOWERS AROUND
THE EASTERN SIERRA AND WESTERN NEVADA TUESDAY/WEDNESDAY.
THE PRIMARY CONCERN WILL BE FOR WINDS AHEAD OF AND BEHIND THE COLD
FRONT: GUSTY SOUTHWEST WINDS AHEAD OF THE FRONT FOR THE SOUTHERN
SIERRA FRONT AND MINERAL COUNTY, AND THEN BREEZY NORTH WINDS BEHIND
IT. WIND GUSTS WILL BE IN THE 25 TO 50 MPH RANGE FOR THE SOUTHERN
SIERRA FRONT IN THE EASTERN SIERRA AS WELL AS AREAS OF MINERAL
COUNTY. LATEST SIMULATIONS SHOW THAT HUMIDITY VALUES WILL STAY
BELOW 15% THROUGH THE AFTERNOON AND LIKELY WON'T START TRENDING
UPWARDS UNTIL AFTER 4PM FOR THOSE AREAS.
WE WILL HEADLINE IN THE FWF THAT THERE MAY BE A COUPLE OF HOURS WITH
CRITICAL CONDITIONS TUESDAY AFTERNOON, DUE TO GUSTY WINDS AND LOW
RELATIVE HUMIDITY. MOISTURE WILL INCREASE RAPIDLY WITH THE
FRONTAL PASSAGE, SO THAT SHOULD HELP TO LIMIT THE LOCALIZED
CRITICAL CONDITIONS BY LATE AFTERNOON/EVENING. WINDS WILL DECREASE
A BIT BEHIND THE FRONT, BUT NORTH WINDS WILL REMAIN BREEZY MUCH
OF THE NIGHT. -EDAN
REV WATCHES/WARNINGS/ADVISORIES
NV...NONE.
CA...NONE.
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO
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