172
FXUS66 KSTO 130451
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
951 PM PDT MON AUG 12 2013
.SYNOPSIS...
A QUIET AND DRY WEATHER PATTERN IS EXPECTED THROUGH EARLY THIS
WEEK EXCEPT FOR A CHANCE OF MOUNTAIN THUNDERSTORMS LATE SATURDAY.
TEMPERATURES WILL BE NEAR NORMAL THEN DECREASE A LITTLE FOR THE
WEEKEND.
&&
.DISCUSSION...
UPPER RIDGE WILL GRADUALLY BUILD OVER NORCAL THROUGH THE WEEK AS
WEAK TROUGH ALONG THE COAST DISSIPATES. NOT MUCH IN THE WAY OF
MOUNTAIN THUNDERSTORM ACTIVITY TODAY WITH A DRIER AND MORE STABLE
ATMOSPHERE IN PLACE. NORTHEAST DRAINAGE WINDS WILL DEVELOP TONIGHT
PUSHING SMOKE FROM THE AMERICAN FIRE INTO THE FOOTHILLS AND
EASTERN VALLEYS. TEMPERATURES ARE RUNNING A COUPLE OF DEGREES
ABOVE YESTERDAY AT THIS TIME AND FORECASTED LOW TEMPERATURES IN
THE MID 50'S TO LOW 60'S ARE ON TRACK. NO EVENING UPDATE IS
NEEDED.
.PREVIOUS DISCUSSION...
THE REGION IS BETWEEN A TROUGH OFF THE COAST AND RIDGE CENTERED
OVER THE ROCKY MOUNTAINS. THIS IS BRINGING A CONTINUED SOUTHWEST
FLOW PATTERN. A WEAK SHORTWAVE PASSING THROUGH IS BRINGING SOME
CONVECTION INTO SISKIYOU COUNTY THIS AFTERNOON. SO FAR ONLY SOME
CUMULUS BUILDUPS ARE EVIDENT ON SATELLITE IMAGERY OVER FAR WESTERN
SHASTA AND WESTERN TEHAMA COUNTIES. STILL SOME TIME FOR
DEVELOPMENT BEFORE SUNSET AND CAN NOT RULE OUT SOME ISOLATED
ACTIVITY. WILL LEAVE IN A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS THERE INTO THE EARLY EVENING FOR NOW.
STILL A CHANCE TO SEE SOME PERSEID METEORS IN MAINLY CLEAR SKIES
TONIGHT OVER MUCH OF THE AREA, ESPECIALLY LATE THIS EVENING AND AFTER
MIDNIGHT. AN EXCEPTION TO THIS IS IN POOR VISIBILITY FROM SMOKE
FROM THE AMERICAN FIRE IN EASTERN PLACER COUNTY. SMOKE FROM THE FIRE
IS CURRENTLY BLOWING TO THE NORTH NORTHEAST. THIS WILL SHIFT
OVERNIGHT WITH A DOWNSLOPE FLOW LIKELY BRINGING SMOKE WESTWARD BACK
INTO THE FOOTHILLS. THIS COULD AFFECT COMMUNITIES AROUND THE
INTERSTATE 80 AND HIGHWAY 50 CORRIDORS INCLUDING SUCH FOOTHILL
TOWNS AS GRASS VALLEY...AUBURN, AND WIEMAR. SOME OF THE SMOKE/HAZE
COULD EVEN FIND ITS WAY INTO THE EASTERN SIDE THE VALLEY BY
MORNING. SOUTHWEST WINDS PICKING UP TOMORROW BY MID DAY SHOULD
SHIFT THE SMOKE TO THE NORTH AND EAST AGAIN CLEARING CONDITIONS
SOME. AS THE FIRE GETS UNDER CONTROL THE SMOKE PRODUCTION SHOULD
DECREASE OVER THE NEXT FEW DAYS.
DRY WEATHER WITH A GRADUAL TEMPERATURE INCREASE IS EXPECTED THROUGH
THIS WEEK. HIGHS WILL BE NEAR NORMAL LEVELS. DELTA BREEZE SHOULD
DECREASE SOME WITH A WEAKER GRADIENT BRINGING SLIGHTLY WARMER LOWS
IN AFFECTED AREAS. EK
&&
.EXTENDED DISCUSSION (FRIDAY THROUGH MONDAY)
UPPER LEVEL TROUGH ALONG THE WEST COAST FRIDAY AND MOVING INLAND
SATURDAY. THIS WILL BRING BELOW NORMAL TEMPERATURES ALONG WITH A
DELTA BREEZE. MAXIMUM TEMPERATURES ARE EXPECTED TO BE IN THE MID
80S TO MID 90S IN THE VALLEY AND 70S IN THE MOUNTAINS. LOW CLOUDS
ARE EXPECTED IN THE DELTA AND POSSIBLY AREAS OF THE SOUTHERN
SACRAMENTO VALLEY FRIDAY AND SATURDAY MORNINGS. SOME CUMULUS MAY
DEVELOP OVER THE HIGHER TERRAIN...ESPECIALLY THE COASTAL RANGE ON
FRIDAY AND THE SIERRA ON SATURDAY. THERE IS A LITTLE MID-LEVEL
MOISTURE ALONG WITH SOME INSTABILITY MOVING INTO THE SIERRA ON
SATURDAY FOR A SLIGHT CHANCE OF THUNDERSTORMS FROM AROUND THE
LASSEN PARK AREA AND WESTERN PLUMAS COUNTY ALONG WITH AREAS NEAR THE
SIERRA CREST.
SOME UNCERTAINTY IN THE LOW MOVING OUT OF THE AREA ON SUNDAY WITH
THE MODELS VARYING ON THE EXITING TRACK AND SPEED. THE SIERRA MAY SEE
SOME CLOUDS WITH SOME WRAP AROUND MOISTURE ON SUNDAY IF THE LOW
MOVES SLOWER AND TO SOUTHEAST. TEMPERATURES MAY WARM UP TO NEAR TO A LITTLE
ABOVE NORMAL ON SUNDAY AS THE LOW MOVES OUT OF THE AREA. HIGH
PRESSURE MAY BUILD IN ON MONDAY FOR MAXIMUM TEMPERATURES WARMING
TO SEVERAL DEGREES ABOVE NORMAL.
&&
.AVIATION...
GENERALLY VFR CONDITIONS FOR THE NEXT 24 HOURS EXCEPT 10-17Z IFR
CONDITIONS WITH STRATUS WEST OF CORDELIA AND MVFR/IFR CONDITIONS
FOR AREAS AROUND THE AMERICAN FIRE INCLUDING KAUN AND KGOO. KBLU
HAS BEEN CLOSED EXCEPT FOR FIREFIGHTING AIRCRAFT. WINDS GENERALLY
10 KTS OR LESS EXCEPT 10 TO 20 KTS IN THE DELTA AND IN THE
AFTERNOON/EARLY EVENING OVER THE HIGHER SIERRA.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$