River Flood Watch 4, NWS Reno, NV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
319 PM PDT SAT JUN 11 2011

.SHORT TERM...
A WEAK SHORTWAVE IS MOVING THROUGH SRN OREGON AND NE CA THIS
AFTERNOON AND HAS BROUGHT SOME HIGH AND MID LEVEL CLOUDS TO THE
FORECAST AREA AS WELL AS SOME LIGHT SHOWERS NORTH OF AROUND
INTERSTATE 80. A LIGHTNING STRIKE CANNOT BE RULED OUT...BUT LOOKS
UNLIKELY WITH THICK CLOUD COVER AND MODEST MID LEVEL INSTABILITY. ANY
SHOWER DEVELOPMENT SHOULD ONLY HOLD TOGETHER THROUGH AROUND 7 OR 8
PM AND THEN THE WAVE WILL BE TOO FAR EAST WHILE THE AIR MASS
STABILIZES WITH LOSS OF DAYTIME HEATING. SKIES SHOULD CLEAR AFTER
MIDNIGHT WITH SUBSIDENCE BEHIND THE WAVE.

WEAK TROUGHINESS WILL REMAIN OVER THE FORECAST AREA SUNDAY WITH
YET ANOTHER WEAK SHORTWAVE AND ASSOCIATED JET STREAM PUSHING INTO
SRN OREGON AND VERY FAR NRN NEVADA LATE SUNDAY AFTERNOON AND
OVERNIGHT. SHOWERS ARE LESS LIKELY WITH THIS WAVE BUT SOME HIGH
CLOUDS ARE AGAIN EXPECTED...ESPECIALLY NORTH OF A
SUSANVILLE/LOVELOCK LINE. TEMPERATURES ARE EXPECTED TO WARM A
COUPLE DEGREES SUNDAY WITH HEIGHTS SLIGHTLY HIGHER COMPARED WITH
TODAY.

THE RIDGE IS EXPECTED TO STRENGTHEN INTO THE FORECAST AREA MONDAY
INTO TUESDAY...BRINGING A SUSTAINED WARMING TREND WITH TEMPS IN THE
MID TO UPPER 80S FOR MOST WESTERN NV VALLEYS AND 70S IN THE
VALLEYS OF THE SIERRA. THIS WILL BRING THE WARMEST TEMPERATURES OF
THE YEAR AND WILL EXACERBATE SNOWMELT RUNOFF WITH POTENTIAL HYDRO
CONCERNS. SEE HYDRO SECTION FOR MORE DETAILS.   MILNE

.LONG TERM...WEDNESDAY THROUGH SATURDAY...
ONLY MINOR CHANGES MADE AS GFS/ECMWF CONTINUE TO STICK TO THEIR OWN
SOLUTIONS REGARDING THE PAC NW TROUGH. THE 12Z ECMWF REMAINS MORE
PROGRESSIVE AND LESS AMPLIFIED WITH THE TROUGH WHEREAS THE 12Z GFS
CONTINUES TO BE SLOWER AND DEEPER. THE GFS APPEARS TO HAVE BETTER
OVERALL SUPPORT FROM ITS ENSEMBLE...BUT IS STILL SLIGHTLY DEEPER AND
COOLER WITH THE TROUGH THAN MOST OF THE INDIVIDUAL ENSEMBLE MEMBERS.
MEANWHILE...THERE IS CONSIDERABLE SPREAD AMONG THE ECMWF ENSEMBLE
DATA...BUT GENERALLY INDICATE A VERY WEAK TROUGH OVER THE WEST. FEEL
THE GFS IS TOO COLD WHILE THE ECMWF IS A TAD TOO WARM. THE CURRENT
FORECAST REFLECTS A COMPROMISE OF THE TWO WITH SEASONAL TEMPERATURES
FOR MID JUNE AND MOSTLY CLEAR TO PARTLY CLOUDY SKIES. WILL HAVE TO
WATCH FOR THE POSSIBILITY OF AFTERNOON CONVECTION OVER MONO/MINERAL
COUNTY...BUT TOO MUCH UNCERTAINTY TO INCLUDE IN THE FORECAST AT THIS
TIME DUE TO MODEL TO MODEL INCONSISTENCIES. SCV

&&

.AVIATION...
GENERALLY VFR THROUGH SUNDAY. FOR THE REMAINDER OF TODAY...A TROUGH
MOVING THROUGH THE REGION WILL BRING SW-W WINDS 10-15 KT WITH GUSTS
UP TO 25 KT THIS AFTERNOON AND EVENING...AND ISOLATED SHOWERS NORTH
OF I-80. FOR SUNDAY...THERE IS A SLIGHT CHANCE OF FOG AT KTRK BTWN
11-14Z...OTHERWISE VFR WITH AFTERNOON WINDS AROUND 10-15 KTS. SCV

&&

.HYDROLOGY...
THE CURRENT MILD CONDITIONS ARE ALLOWING THE HIGH ELEVATION
SNOWPACK TO RAPIDLY MELT OFF. THIS HAS LED TO SIGNIFICANT RISES ON
ALL RIVERS...CREEKS AND STREAMS COMING OUT OF THE HIGH SIERRA. AS
TEMPERATURES CONTINUE TO WARM INTO EARLY NEXT WEEK...RUNOFF WILL
ACCELERATE AND IS EXPECTED TO BRING PORTIONS OF THE CARSON AND
WALKER RIVERS TO ABOVE FLOOD STAGE. THE WEST WALKER RIVER IS
EXPECTED TO GET ABOVE FLOOD STAGE AROUND TUESDAY. THE MAIN STEM
WALKER IS EXPECTED TO GET TO FLOOD STAGE MONDAY MORNING FROM MASON
TO WEBBER DAM WITH ONLY MINOR LOWLAND FLOODING EXPECTED INITIALLY.
FURTHER RISES ON THE WALKER ARE EXPECTED AS THE WEEK PROGRESSES.
FOR THE CARSON RIVER...MINOR FLOODING IS POSSIBLE ON THE WEST FORK
EARLY NEXT WEEK...BUT ENOUGH SNOWPACK HAS ALREADY MELTED THIS
SEASON THAT IMPACTS ARE ONLY EXPECTED TO BE MINOR. RISES ON RIVERS
WILL NEED TO BE CLOSELY MONITORED FROM MONDAY ON. ADDITIONAL
DETAILS ON FLOOD WATCHES AND WARNINGS CAN BE FOUND IN THE
HYDROLOGY PRODUCTS ISSUED BY NWS RENO AT WWW.WEATHER.GOV/RENO.
MILNE

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.

&&

HTTP://WEATHER.GOV/RENO