120
FXUS65 KREV 120954
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
254 AM PDT MON MAY 12 2008
SHORT TERM
UPPER LOW CURRENTLY SPINNING OVER NRN IDAHO WITH SHORTWAVE ENERGY
ROTATING AROUND IT OVER NRN NEVADA. THE ASSOCIATED COLD FRONT HAS
BECOME BROKEN APART AND DISORGANIZED ACROSS CENTRAL NEVADA
OVERNIGHT ALLOWING WINDS TO DECREASE WHILE COOLER TEMPS SLOWLY
SETTLE INTO THE GREAT BASIN. NORTHERLY WINDS WILL PICK BACK UP
LATER THIS MORNING HOWEVER SPEEDS WILL BE LESS THAN YESTERDAY SO
NO LAKE WIND OR BLOWING DUST CONCERNS ARE EXPECTED TODAY.
TEMPERATURES WILL COOL AROUND 10 DEGREES FROM YESTERDAY TO VALUES
SLIGHTLY BELOW NORMAL.
HIGH PRESSURE OVER THE ERN PACIFIC BEGINS TO SHIFT EAST BY THIS
AFTERNOON BRINGING MUCH WARMER TEMPERATURES ALOFT. MODELS CONTINUE
THE TREND OF BRINGING A GOOD SLUG OF MOISTURE INTO THE NRN AND ERN
ZONES TUESDAY WHICH WILL LIMIT THE SOLAR RADIATION AND SURFACE
HEATING. MODELS ALSO KEEP MORE OF A COOL NORTH FLOW THROUGH
WEDNESDAY RATHER THAN A SWITCH TO A WARMER WESTERLY FLOW. THIS
BRINGS UP A LITTLE UNCERTAINTY ON JUST HOW FAST TEMPERATURES WARM
THROUGH THE WEEK...HOWEVER EITHER WAY THE UPPER RIDGE TAKES A
STRONG HOLD ON THE WEST COAST THIS WEEK.
AS SURFACE HIGH PRESSURE BUILDS INTO THE GREAT BASIN WEDNESDAY AND
THE THERMAL TROUGH DEVELOPS OVER CALIFORNIA...NORTHEAST GRADIENTS
TIGHTEN ALONG THE SIERRA. THIS SHOULD PRODUCE GUSTS OF 30 TO 40
MPH ALONG THE SIERRA CREST WHICH MAY PARTIALLY MIX DOWN TO THE
LAKE TAHOE LEVEL CAUSING LAKE WIND ISSUES WEDNESDAY NIGHT. JORDAN
LONG TERM /THURSDAY THROUGH SUNDAY/
LITTLE CHANGE IN THE FORECAST. UPPER RIDGE MOVES OVER THE WEST ON
WEDNESDAY AND DEVELOPS INTO AN OMEGA BLOCK BY FRIDAY. MODELS DOING
OK...BUT WILL LEAN ON THE ECMWF AS IT HAS REMAINED CONSISTENT
AND HAS SUPPORT FROM MOST OF THE ENSEMBLE DATA. GFS TRIES ONCE AGAIN
TO FLATTEN A STRONG RIDGE FASTER THAN MOST OF THE OTHER
GUIDANCE...SO WILL DISCARD IT AFTER SATURDAY.
HIGHEST CONFIDENCE REMAINS IN MAXIMUM TEMPERATURES FRIDAY THROUGH
SUNDAY WILL BE 15-20 DEGREES ABOVE NORMAL. TEMPERATURES SHOULD MAX
OUT ONCE THE RIDGE MOVES OVERHEAD OR SLIGHTLY EAST OF THE
AREA...WHICH THE 00Z/12 ECMWF SHOWS FOR SATURDAY AND SUNDAY. NCEP
ENSEMBLE 850 MB TEMPERATURE ANOMALIES PEAK ON SATURDAY AND
SUNDAY...SUPPORTS THE ECMWF SOLUTION.
NEW RECORD HIGHS ALMOST CERTAIN THIS THE WEEKEND...PERHAPS SOONER.
CURRENT FORECAST HIGH FOR RENO ON SATURDAY IS 92...RECORD IS 90. THE
NCEP ENSEMBLE PROBABILITY OF THE 850MB TEMPERATURES EXCEEDING 2
STANDARD DEVIATIONS /RARE AND POTENTIAL RECORD EVENT/ IS 90 PERCENT
FOR THURSDAY-MONDAY. IF THIS PANS OUT THE LATEST FORECAST HIGHS MAY
BE A BIT ON THE LOW SIDE.
FOR THUNDERSTORM CHANCES...
CUMULUS SHOULD START TO BUILD OVER THE CENTRAL SIERRA ON
FRIDAY...THEN SPREAD NORTHWARD THROUGH THE WEEKEND. THIS IS SHOWN
WELL IN THE ECMWF...WHICH GENERATES QPF SATURDAY AND SUNDAY OVER THE
CENTRAL SIERRA...SPREADING INTO WESTERN NEVADA ON MONDAY. THIS
RAISES CONFIDENCE IN THE THUNDERSTORM CHANCES...BUT WILL LEAVE THE
POTENTIAL AT 10 PERCENT AND NOT MENTION THUNDERSTORMS IN THE
FORECAST. BRONG
CLIMATE
RECORD HIGHS FOR RENO-TAHOE AIRPORT LATE THIS WEEK.
THU 15TH 92 SET IN 1927.
FRI 16TH 95 SET IN 1970.
SAT 17TH 90 SET IN 1954...1970...1973 AND 2006.
SUN 18TH 94 SET IN 1954.
MON 19TH 93 SET IN 1954.
AVIATION
CLOUD BAND BEHIND COLD FRONT ACROSS CENTRAL NEVADA WILL ERODE AFTER
18Z AS DRIER AIR MOVES IN FROM THE NORTH. VFR CONDITIONS THROUGH MID
WEEK AS HIGH PRESSURE BEGINS TO BUILD OVER THE AREA. BRONG
REV WATCHES/WARNINGS/ADVISORIES
NV...NONE.
CA...NONE.
HTTP://WEATHER.GOV/RENO
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