Damaging Wind in California, April 24, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
300 PM PDT FRI APR 24 2009

.DISCUSSION...
A COLD UPPER LEVEL LOW GRADUALLY MOVING SOUTH THROUGH INTERIOR
NORTHERN CALIFORNIA BRINGING SOME INSTABILITY FOR THE FORMATION OF
CUMULUS CLOUDS AND ISOLATED SHOWERS AND THUNDERSTORMS.  A FEW
LIGHTNING STRIKES WITH ISOLATED THUNDERSTORMS OVER THE COASTAL RANGE
AND IN THE NORTHEAST FOOTHILLS SO FAR THIS AFTERNOON. ADDITIONAL
SHOWERS AND THUNDERSTORMS ARE POSSIBLE IN THE SOUTHERN PORTION OF
THE AREA TONIGHT AS THE LOW SLOWLY DIPS SOUTH.  THE THREAT OF
THUNDERSTORMS WILL BE GREATEST AROUND THE SOUTHERN SACRAMENTO
VALLEY AND NORTHERN SAN JOAQUIN VALLEY THIS EVENING AS THE DYNAMICS
MOVE SOUTH WITH THE LOW.  THE LOW MOVES TO THE SOUTH AND EAST
OVERNIGHT TONIGHT FOR LINGERING SHOWERS OVER THE EASTERN MOUNTAINS
AND POSSIBLY THE NORTHERN SAN JOAQUIN VALLEY BUT THE REST OF THE
AREA SHOULD START TO SEE SOME CLEARING. BY SATURDAY MORNING THE LOW
IS IN NEVADA FOR JUST ISOLATED LINGERING SHOWERS IN THE
SIERRA...MAINLY SOUTH OF HIGHWAY 50. PRECIPITATION AMOUNTS WILL BE
VARIABLE DUE TO THE CONVECTIVE NATURE OF THE SHOWERS AND
THUNDERSTORMS.

THE LOW BROUGHT COLD AIR INTO THE REGION WITH TEMPERATURES AROUND 3
TO 10 DEGREES COOLER TODAY IN THE VALLEY AND AROUND 15 DEGREES
COOLER IN THE SIERRA THIS AFTERNOON COMPARED TO YESTERDAY. MINIMUM
TEMPERATURES WILL BE COOLER IN MOST PLACES TONIGHT WITH SKIES
CLEARING IN MOST LOCATIONS AND THE COLD AIR IN PLACE.

WEAK RIDGE OVER NORTHERN CALIFORNIA ON SATURDAY BEHIND THE LOW FOR
WARMER TEMPERATURES AND CLEARING SKIES. TROUGH DEEPENS OVER THE
GREAT BASIN WITH SOME WEAK ENERGY COMING DOWN THE BACK SIDE THROUGH
THE PACIFIC NORTHWEST ON SUNDAY BRINGING SOME CLOUDS.  A STRONGER
WAVE MOVES DOWN ON MONDAY BRINGING COOLER TEMPERATURES ALONG WITH A
CHANCE OF PRECIPITATION...MAINLY OVER THE MOUNTAINS. HSO

.EXTENDED (MONDAY NIGHT THROUGH FRIDAY)...COOL AND UNSETTLED WEATHER
WILL RETURN TO NORTHERN CALIFORNIA NEXT WEEK...AS ANOTHER TROUGH OF
LOW PRESSURE DIGS OVER THE REGION AND STAYS PUT.  THE 12Z GFS SEEMS
TO MESH IN TIMING AND PLACEMENT PRETTY WELL WITH THE 00Z RUNS OF THE
ECMWF AND UKMET.  THEREFORE...INCREASED POPS A LITTLE...AND COOLED
TEMPERATURES A BIT ACROSS THE REGION FOR MONDAY NIGHT THROUGH
WEDNESDAY.  HOWEVER...THE 12Z RUNS OF THE ECMWF AND THE UKMET HAVE
COME IN A LITTLE FURTHER NORTH...WHICH SUGGEST THAT THE BULK OF THE
MOISTURE WOULD MOST LIKELY REMAIN TO OUR NORTH AND EAST.  AT THIS
TIME...IT SEEMS LIKE THERE HAS NOT BEEN TO MUCH RUN TO RUN
CONSISTENCY BETWEEN THE MODELS...SO CONFIDENCE IS KIND OF LOW AS TO
WHAT EXACTLY WILL HAPPEN.  KEPT ONLY SLIGHT CHANCE POPS OVER THE
MOUNTAINS FOR THURSDAY AND FRIDAY AS THE LOW STARTS TO SHIFT
EAST...AND WARMED TEMPERATURES BACK TO NEAR NORMAL.  PALMER

&&

.AVIATION...THE UPPER LEVEL LOW OVER NORTHERN CALIFORNIA WILL
CONTINUE TO DIG TO THE SOUTH SOUTHEAST OVER THE NEXT 24 HOURS...WITH
PREDOMINATELY VFR CONDITIONS PREVAILING.  THE NORTHERN INTERIOR WILL
CONTINUE TO SEE ISOLATED SHOWERS AND THUNDERSTORMS THROUGH THE
EVENING HOURS OVER THE CENTRAL AND NORTHERN SACRAMENTO VALLEY AND
SURROUNDING MOUNTAINS...WITH AREAS OF MVFR CONDITIONS POSSIBLE.  THE
SHOWER ACTIVELY WILL LIKELY SHIFT SOUTHWARD ACROSS THE NORTHERN
INTERIOR THROUGH THE EVENING HOURS...BEFORE TAPERING OFF AFTER
MIDNIGHT.  OTHERWISE...EXPECT LOCALLY GUSTY CONDITIONS TO CONTINUE
THROUGH THE EVENING HOURS...ESPECIALLY ACROSS THE DELTA AND NORTHERN
SAN JOAQUIN VALLEY WITH SUSTAINED SOUTHWEST WINDS 17-25 KNOTS AND
GUSTS UP TO 35 KNOTS POSSIBLE.

&&

.STO WATCHES/WARNINGS/ADVISORIES...NONE.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SACRAMENTO CA
700 AM PDT FRI APR 24 2009

CAZ013>019-063-064-066>069-241400-
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-
700 AM PDT FRI APR 24 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR INTERIOR NORTHERN CALIFORNIA.

.DAY ONE...TODAY

EXPECT SCATTERED SHOWERS ACROSS THE REGION TODAY WITH ISOLATED
THUNDERSTORMS OVER THE NORTHERN AND COASTAL MOUNTAINS TO INCLUDE THE
NORTHERN SACRAMENTO VALLEY.

.DAYS TWO THROUGH SEVEN... SATURDAY THROUGH THURSDAY

NO SIGNIFICANT WEATHER EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS TO THEIR LOCAL NATIONAL WEATHER SERVICE OFFICE.

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

JCLAPP