Wind Advisory 10, NWS Sacramento, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
355 AM PDT THU MAR 26 2009

.DISCUSSION...
UPPER LEVEL LOW NEAR KSLC WILL BE DROPPING TOWARDS THE 4-CORNERS
AREA TODAY WHILE THE UPPER LEVEL JET DIVES SEWD ACROSS NV. NORCAL
WILL BE ON THE SUBSIDENCE...LARGE SCALE DESCENT SIDE OF THE JET
TODAY. MOSTLY HIGH LEVEL MOISTURE WAS STREAMING SEWD OVER NORCAL AS
MOISTURE SPILLS OVER THE AMPLIFIED ERN PAC RIDGE EXTENDING INTO
B.C./WRN CANADA. NOW A DECK OF MID CLOUDS HAS FORMED OVER THE HIGHER
TERRAIN. PRESSURE RISES OVER THE PAC NW ARE INCREASING NLY GRADIENTS
WITH MFR-RDD GRADIENT UP TO 6 MBS AT 09Z. FORECAST GRADIENTS
INCREASE TO 8 TO 9 MBS FROM MFR-SAC TODAY WITH POTENTIAL FOR A
SOMEWHAT MARGINAL WIND ADVISORY EVENT. THE WINDS ALOFT ARE NOT
OVERLY IMPRESSIVE...GENERALLY LESS THAN 40 KTS...BUT THE GRADIENT
ALONE AND THE FORECAST STRONG MID LEVEL CAA SUGGEST STEEPENING LAPSE
RATES AND GOOD POTENTIAL TO VERIFY THE SUSTAINED WIND SPEEDS OF 25
MPH OVER MUCH OF THE SAC VLY/DELTA AREA TODAY. HAVE ISSUED WIND
ADVSRYS FOR THESE AREAS. ADIABATIC WARMING EFFECTS ARE EXPECTED TO
OFFSET THE MID LEVEL CAA RESULTING IN SLIGHT WARMING OVER INTERIOR
NORCAL.

AS THE UPPER JET DROPS FURTHER S TONIGHT...PRESSURE RISES OVER THE
INTERIOR MTN WEST WILL SWITCH AND INCREASE GRADIENTS TO A NE/ELY
GRADIENT...AT ABOUT 6 TO 8 MBS BETWEEN 06Z-12Z FRI. BUFKIT FOR BLU
ALSO SHOWS AN INCREASE IN THE 1 TO 2 THOUSAND FT LEVEL TO AROUND 40
KTS CAUSING A LOCALLY STRONG KATABATIC WIND FROM THE SIERNEV AND
INTO A PORTION OF THE COASTAL RANGE...ZONE 64 LAKE CO. 925 MBS WINDS
SUGGEST A NLY BARRIER JET WILL FORM ON THE W SIDE OF THE VALLEY OR A
PORTION OF THE COASTAL RANGE WITH PEAK SPEEDS AROUND 44 KTS IN THE
VCNTY OF NAPA/SRN LAKE/SOLANO CO AREAS. THIS PHENOMENON USUALLY
BEGINS AROUND MIDNIGHT AND LASTS UNTIL LATE MORNING WHEN THE UPSLOPE
FLOW BEGINS TO WEAKEN THE DOWNSLOPE FLOW. AGAIN THIS LOOKS LIKE
SOMEWHAT OF A MARGINAL EVENT FOR THE SIERNEV AND LAKE CO BUT WE
EXPECT TO VERIFY ON 40+ MPH WIND GUSTS IN THESE AREAS. A STRONG
KATABATIC WIND COULD DEVELOP OFF THE VACA MTNS AT TIMES AS WELL
GIVEN THIS PATTERN.

HIGH PRESSURE IS FORECAST TO BUILD OVER THE AREA ON FRI AS THE LOW
PRESSURE SYSTEM MOVES FROM KSLC ACROSS THE DESERT SW AND INTO THE
SRN PLAINS. SYNOPTIC WARMING IS FORECAST TO BRING A VERY MILD DAY TO
NORCAL WITH TEMPS REACHING NEAR 80 IN THE NRN SAC VLY.

THE NEXT SHORT WAVE FROM THE PACIFIC IS FORECAST TO WEAKEN THE RIDGE
OVER THE INTERIOR OF NORCAL ON SAT RESULTING IN COOLING FOR THE
WEEKEND...AND POSSIBLY MORE GUSTY NLY WINDS ON SUN. THERE IS A
CONSIDERABLE DIFFERENCE BETWEEN THE GFS/ECMWF WITH THIS SHORT WAVE
AS THE ECMWF SHOWS LESS AMPLITUDE THAN THE GFS. FOR NOW WE FAVOR THE
GFS AS THIS FOLLOWS THE CLIMATOLOGICAL PATTERN OF MIGRATORY SHORT
WAVES INTO THE GREAT BASIN AT THIS TIME OF YEAR.     JHM

.EXTENDED (MONDAY THROUGH THURSDAY)...
TEMPERATURES ARE EXPECTED TO WARM UP ON MONDAY WITH 850MB
TEMPERATURES AND 1000-500MB THICKNESSES RISING AS THE RIDGE OF HIGH
PRESSURE OVER THE EASTERN PACIFIC NUDGES INTO NORTHERN CALIFORNIA.
THE MODELS STILL HAVE VARIED SOLUTIONS WITH THE TRACK AND TIMING OF
THE TROUGH FOR TUESDAY THROUGH THURSDAY. THE 06Z OPERATIONAL GFS
DEEPENS THE TROUGH OVER THE GREAT BASIN ON WEDNESDAY. THE GFS
ENSEMBLE SPREAD IS AROUND 70M INDICATING VARIED SOLUTIONS FOR THE
PERIOD. THE 00Z ECMWF HAS A WEAKER SHORTWAVE THAT PROGRESSES EAST
ACROSS CANADA AND THE NORTHERN STATES. ANOTHER TROUGH IS ALONG THE
PACIFIC NORTHWEST COAST ON WEDNESDAY AND DIGS OVER THE WEST COAST ON
THURSDAY ON THE 00Z ECMWF. THE CURRENT FORECAST LEANS MORE TOWARDS
THE GFS WITH A DRY FORECAST AND NEAR TO SLIGHTLY ABOVE NORMAL
TEMPERATURES. THE NORTHERLY GRADIENT WILL PICK UP BEHIND THE TROUGH
TUESDAY NIGHT INTO WEDNESDAY BRINGING BREEZY AND GUSTY NORTHERLY
WINDS AGAIN. ALTHOUGH IF THE ECMWF IS CORRECT WE COULD SEE A CHANCE
OF PRECIPITATION IN THE NORTHERN MOUNTAINS ON THURSDAY.   HSO

&&

.AVIATION...
VFR CONDITIONS ARE EXPECTED THROUGH FRIDAY AS NORTHERN CALIFORNIA IS
BETWEEN A RIDGE OF HIGH PRESSURE OVER THE EASTERN PACIFIC AND A
TROUGH OF LOW PRESSURE OVER THE GREAT BASIN. NORTHERLY WINDS ARE
EXPECTED TO INCREASE TODAY WITH THE STRENGTHENING OF THE SURFACE
PRESSURE GRADIENT AS LOW PRESSURE DEEPENS OVER THE GREAT BASIN.
NORTHWESTERLY TO NORTH WINDS OF 20 TO 30 KTS WITH GUSTS UP TO 35 KTS
ARE EXPECTED IN THE VALLEY BEGINNING AROUND 18Z TODAY. THE WINDS
WILL DECREASE IN THE THE VALLEY OVERNIGHT AS THE ATMOSPHERE
DECOUPLES. NORTHEASTERLY WINDS GUSTS UP TO 55 KTS ARE EXPECTED
THROUGH FAVORABLY ORIENTED CANYONS AND OVER RIDGES.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM NOON TODAY TO 7 PM PDT THIS EVENING FOR CARQUINEZ
STRAIT AND DELTA-CENTRAL SACRAMENTO VALLEY-NORTHERN SACRAMENTO
VALLEY-SOUTHERN SACRAMENTO VALLEY.

WIND ADVISORY FROM 11 PM THIS EVENING TO 11 AM PDT FRIDAY FOR CLEAR
LAKE/SOUTHERN LAKE COUNTY-WEST SLOPE NORTHERN SIERRA NEVADA-WESTERN
PLUMAS COUNTY/LASSEN PARK.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SACRAMENTO CA
600 AM PDT WED MAR 25 2009

CAZ013>019-063-064-066>069-261400-
SHASTA LAKE AREA/NORTHERN SHASTA COUNTY-
BURNEY BASIN/EASTERN SHASTA COUNTY-NORTHERN SACRAMENTO VALLEY-
CENTRAL SACRAMENTO VALLEY-SOUTHERN SACRAMENTO VALLEY-
CARQUINEZ STRAIT AND DELTA-NORTHERN SAN JOAQUIN VALLEY-
MOUNTAINS SOUTHWESTERN SHASTA TO NORTHERN LAKE COUNTIES-
CLEAR LAKE/SOUTHERN LAKE COUNTY-MOTHERLODE-
EAST FOOTHILLS/NORTH SACRAMENTO VALLEY-
WESTERN PLUMAS COUNTY/LASSEN PARK-WEST SLOPE NORTHERN SIERRA NEVADA-
600 AM PDT WED MAR 25 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR INTERIOR NORTHERN CALIFORNIA.

.DAY ONE...TODAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN... THURSDAY THROUGH TUESDAY

HIGH PRESSURE WILL BUILD INTO OREGON AND THE GREAT BASIN THURSDAY
AND FRIDAY RESULTING IN THE POTENTIAL FOR NORTHERLY AND
NORTHEASTERLY BREEZY TO WINDY CONDITIONS ACROSS MUCH OF THE REGION
THURSDAY AFTERNOON THROUGH FRIDAY.  WINDS IN THE CENTRAL VALLEY MAY
WEAKEN SOMEWHAT DURING THE OVERNIGHT HOURS.

THE LATEST WEATHER INFORMATION IS AVAILABLE ON THE INTERNET AT
(LOWER CASE): HTTP://WWW.WRH.NOAA.GOV/STO

JCLAPP