Wildfire in California, August 17 to 31, 2013

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
246 PM PDT SAT AUG 17 2013

.SYNOPSIS...
SLIGHT CHANCE TO CHANCE OF THUNDERSTORMS SUNDAY INTO THURSDAY
AS AN OFFSHORE LOW PRESSURE SYSTEM GRADUALLY MOVES THROUGH
CALIFORNIA. TEMPERATURES WILL TREND ABOVE NORMAL THE NEXT COUPLE
OF DAYS, WITH SUNDAY AND MONDAY BEING THE HOTTEST DAYS OF THE
WEEK.

&&

.DISCUSSION...
STRATUS ALONG THE COAST HAS BEEN ABSENT BUT IS TRYING TO PUSH ITS
WAY TOWARDS THE COAST. MARINE DEPTH REMAINS SHALLOW AT AROUND 1000
FEET. TEMPERATURES RANGE FROM A LITTLE BELOW TO SLIGHTLY WARMER
THAN YESTERDAYS VALUES AT THIS HOUR AND SHOULD END UP BEING
SLIGHTLY WARMER FOR WELL INLAND PLACES TO ABOUT THE SAME OR LOWER
FOR THE SACRAMENTO REGION FOR THE DAYTIME HIGHS. MID TO HIGH
CLOUDS HAVE HELPED TO KEEP TEMPERATRUES A LITTLE LOWER THAN
EXPECTED.

ON SUNDAY THE LOW PRESSURE AREA OFF THE BAY AREA WILL INCREASE
THUNDERSTORM CHANCES OVER THE CREST. HIGH PRESSURE OVER THE
INTERIOR WILL SEND TEMPERATURES OVER 100 DEGREES IN THE CENTRAL
VALLEY. SUNDAY NIGHT INTO MONDAY MORNING THERE IS SOME INSTABILITY
INDICATED AROUND ALONG A LINE FROM AROUND SACRAMENTO EAST AND
SOUTHEAST INTO THE SIERRA NEVADA THAT MAY GIVE US A CHANCE OF A
THUNDERSTORM MOVING INTO THE FOOTHILLS AND VALLEY. PRECIPITABLE
WATERS WILL GRADUALLY INCREASE OVER THE INTERIOR THE NEXT COUPLE
OF DAYS SO EXPECT THE MORE ORGANIZED(STRONGER) THUNDERSTORMS TO
CONTAIN A DECENT AMOUNT OF RAIN.

THE LOW LINGERS OFF THE COAST THROUGH MID WEEK AND WILL KEEP
CHANCES OF THUNDERSTORMS OVER THE INTERIOR. BY TUESDAY THE LOW
MOVES CLOSER TOWARDS THE BAY AREA AND THE DELTA BREEZE SHOULD
START TO INCREASE WHICH SHOULD LEAD TO SOME COOLING OVER THE
INTERIOR. THERE LOOKS LIKE AN OUTSIDE CHANCE THAT THE DELTA
BREEZE MIGHT INCREASE DURING THE DAY ON MONDAY TO START THE
DOWNWARD TREND IN TEMPERATURES A DAY EARLIER FOR THE SACRAMENTO
REGION. FURTHER INLAND AREAS WILL NEED TO WAIT AT LEAST ONE MORE
DAY.

.EXTENDED DISCUSSION (WEDNESDAY THROUGH SATURDAY)

ANOTHER DAY WITH THE THREAT OF SHOWERS AND THUNDERSTORMS CONTINUES
ON WEDNESDAY WITH THE CENTER OF THE UPPER LOW AROUND THE BAY
AREA. GOOD DIFFLUENT FLOW CONTINUES OVER THE FORECAST AREA WITH
BEST CHANCES FOR CONVECTION IN THE MOUNTAINS. SOME STORMS ARE
POSSIBLE IN THE VALLEY...MAINLY FROM SACRAMENTO NORTHWARD.
THUNDERSTORMS LINGER OVER THE NORTHERN MOUNTAINS ON
THURSDAY/THURSDAY EVENING AS THE PERSISTENT UPPER LOW GRADUALLY
TRACKS ACROSS NORTHERN CALIFORNIA. DRYING CONDITIONS SHOULD SPREAD
INTO THE SOUTHERN PORTION OF THE FORECAST AREA. THE ECMWF MODEL
WHICH WAS MUCH SLOWER THAN THE GFS WITH THE LOW HAS NOW COME INTO
GOOD AGREEMENT WITH IT. THIS TIMING SUGGESTS THE LOW SHOULD
WEAKEN AND EXIT THE REGION OVERNIGHT WITH DRY WEATHER FOR FRIDAY
AND SATURDAY WITH STABLE SOUTHWEST FLOW. TEMPERATURES SHOULD BE
AT TO A LITTLE BELOW NORMAL. EK

&&

.AVIATION...

VFR CONDITIONS CONTINUE OVER TAF SITES OVER THE NEXT 24 HOURS. A
FEW ISOLATED TSRA POSSIBLE OVER ALPINE COUNTY LATE THIS AFTERNOON. LCL
IFR/MVFR CONDITIONS IN SMOKE VICNITY OF WILDFIRES S OF KBLU AND E OF
KOVE. ISOLATED TSRA POSSIBLE OVER THE MOUNTAINS AFTER 18Z. LIGHT
WINDS EXCEPT LOCAL GUSTS TO 25 KT THROUGH STRAIT. EK

&&

.STO WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM MONDAY MORNING THROUGH WEDNESDAY EVENING
BURNEY BASIN / EASTERN SHASTA COUNTY...CLEAR LAKE/SOUTHERN LAKE
COUNTY...MOTHERLODE...MOUNTAINS SOUTHWESTERN SHASTA COUNTY TO
NORTHERN LAKE COUNTY...NORTHEAST FOOTHILLS/SACRAMENTO VALLEY...
SHASTA LAKE AREA / NORTHERN SHASTA COUNTY...WEST SLOPE NORTHERN
SIERRA NEVADA...WESTERN PLUMAS COUNTY/LASSEN PARK.

&&