Wildfire in California, August 1 to 17, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
330 PM PDT SAT AUG 1 2009

.DISCUSSION...
MODERATE FLOW WILL CONTINUE THROUGH THE DELTA THE NEXT FEW DAYS. THE
GRADIENT BETWEEN SFO AND SAC IS FAIRLY SIMILAR TO YESTERDAY AND
WINDS ARE STARTING TO PICK UP AGAIN IN THE DELTA AFTER SLACKENING A
LITTLE TODAY. THE MARINE LAYER IS FLUCTUATING A LITTLE DURING THE
DAY AND IS NOW AT 1400 FEET DEEP. LOW CLOUDS ARE STILL LINGERING
AROUND SAN FRANCISCO WILL MOVE BACK INTO THE WESTERN PORTIONS OF THE
DELTA THIS EVENING. 850 MB TEMPERATURES WILL CONTINUE TO COOL FOR
SUNDAY SO EXPECT TEMPERATURES TO COOL A LITTLE THROUGHOUT THE REGION
ON SUNDAY. THERE WILL BE A CHANCE THE NEXT SEVERAL MORNINGS FOR SOME
LOW CLOUDS ADVECTING INTO THE SACRAMENTO AREA WITH THE UPPER LEVEL
LOW PRESSURE AREA MOVING SLIGHTLY CLOSER TO THE COAST. THIS SHOULD
HELP TO INCREASE THE MARINE LAYER. TEMPERATURES WILL ALSO BE FALLING
TO BELOW NORMAL FOR THIS TIME OF YEAR THROUGH MOST OF THIS COMING
WEEK.

SHOWERS AND ISOLATED THUNDERSTORMS ARE DEVELOPING ON THE EAST SIDE
OF THE CREST AND MOVING NORTHWARD ALONG THE CREST THIS AFTERNOON.
SOME OF THIS ACTIVITY IS EXPECTED TO MOVE OVER ONTO THE WESTERN
SLOPES LATER THIS AFTERNOON AND EVENING AND SPREAD THROUGH THE
BURNEY BASIN. A VORT MAX LATE TONIGHT MOVES OVER WESTERN PLUMAS AND
EASTERN SHASTA COUNTY. THIS MAY HELP TO KEEP SOME SHOWER AND
ISOLATED THUNDERSTORM ACTIVITY LINGERING FOR MOST OF THE NIGHT
IN THAT AREA.

FOR SUNDAY AND MONDAY ITS HARDER TO SAY IF ANY ACTIVITY WILL FORM
OVER THE WESTERN SLOPES. THE BEST CHANCES OF ANY ACTIVITY SEEMS TO
MOVE OVER THE SOUTHERN CASCADES AND PLACES NORTHWARD. AS THE LOW
MOVES CLOSER TO THE COAST ON TUESDAY GREATER ACTIVITY MAY DEVELOP
ALONG THE COASTAL RANGE FROM NORTHERN LAKE COUNTY AND PLACES
NORTHWARD.

.EXTENDED DISCUSSION (WEDNESDAY THRU SATURDAY)...
THE UPPER LOW WHICH HAS BEEN LINGERING OFF THE COAST WILL FINALLY
MOVE ONSHORE WEDNESDAY NIGHT INTO THURSDAY. THIS WILL BRING COOLER
TEMPERATURES WITH HIGHS AROUND 5 TO 10 DEGREES BELOW NORMAL. THE
GREATEST COOLING IS EXPECTED OVER THE NORTHERN MOUNTAINS AND
NORTHERN SACRAMENTO VALLEY. MODELS CONTINUE TO HAVE TROUBLE DEALING
WITH THE EXACT PATH OF THE CLOSED LOW...AS IS TYPICAL. THE 12Z ECMWF
HAS TRENDED QUITE A BIT FURTHER SOUTH WITH THE LOW FROM THE 00Z RUN
FOR WEDNESDAY AND THURSDAY...TRACKING IT MORE ACROSS NORTHERN
CALIFORNIA THAN SOUTHERN OREGON. THE LATEST GFS IS FURTHER NORTH AND
SLOWER WITH THIS SYSTEM. HAVE ADDED THE POSSIBILITY OF PRECIPITATION
FOR WEDNESDAY AND THURSDAY OVER THE NORTHERN MOUNTAINS. IF -16 C 500
MB TEMPERATURES PASS OVER INSTABILITY COULD GENERATE SOME AFTERNOON
CONVECTION OVER THAT AREA...BUT DUE TO THE UNCERTAINTY WILL JUST
INTRODUCE A SLIGHT CHANCE OF SHOWERS FOR NOW.

LINGERING SHOWERS ARE POSSIBLE OVER THE MOUNTAINS OF SHASTA COUNTY
ON FRIDAY. THE LOW SHOULD BEGIN TO DEPART THE AREA LATE IN THE DAY
AND INTO SATURDAY BRINGING DRIER AND WARMING CONDITIONS. BELOW
NORMAL TEMPERATURES MAY WELL CONTINUE INTO THE WEEKEND IN SPITE OF
THE LOW MOVING OUT AS A GENERALLY TROFFY PATTERN PERSISTS OVER THE
WEST COAST.

&&

.AVIATION...
GENERAL VFR CONDITIONS WILL CONTINUE OVER THE VALLEY OVER THE NEXT
24 HOURS. SUSTAINED SOUTHWESTERLY WINDS AROUND 20KTS THROUGH THE
CARQUINEZ STRAIT WITH GUSTS TO 30KTS WILL CONTINUE OVERNIGHT.
ISOLATED THUNDERSTORMS HAVE FORMED THIS AFTERNOON NEAR THE NRN
SIERRA AND SRN CASCADES CREST AND WILL CONTINUE THROUGH THE EVENING.
SOME STORMS MAY CONTINUE OVER THE CREST NORTH OF INTERSTATE 80 AFTER
MIDNIGHT. WILDFIRE SMOKE AROUND MAY LOCALLY REDUCE VISIBILITIES IN
CALAVERAS AND TUOLUMNE COUNTIES THROUGH SUNDAY. STRATUS COULD BRING
LOCAL MVFR/IFR CIGS INTO THE SACRAMENTO METRO AREA SUNDAY MORNING.

&&

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

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SACRAMENTO CA
330 AM PDT SAT AUG 1 2009

CAZ013>019-063-064-066>069-021400-
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-
330 AM PDT SAT AUG 1 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR INTERIOR NORTHERN CALIFORNIA.

.DAY ONE...TODAY

ISOLATED THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND EVENING OVER
THE BURNEY BASIN...THE HIGHER TERRAIN OF THE NORTHERN SIERRA
NEVADA...WESTERN PLUMAS COUNTY AND THE LASSEN PARK AREA...OTHERWISE
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN... SUNDAY THROUGH FRIDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

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