Area Forecast Discussion
Issued by NWS Sacramento, CA

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000
FXUS66 KSTO 022055
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
155 PM PDT THU JUL 2 2015

.SYNOPSIS...
HOT WEATHER WILL CONTINUE BUT SLIGHT COOLING IS EXPECTED THROUGH
THE HOLIDAY WEEKEND. MOUNTAIN THUNDERSTORMS ARE POSSIBLE EACH
AFTERNOON AND EVENING THROUGH THE WEEKEND WITH THE POSSIBILITY OF
A STRAY SHOWER OR TWO IN THE VALLEY LATER THIS EVENING AND
TONIGHT. DECREASING CHANCES OF MOUNTAIN THUNDERSTORMS NEXT WEEK.

&&

.DISCUSSION...

CLOUDS HAVE CLEARED ACROSS NORTHERN TWO-THIRDS OF AREA ALLOWING
FOR PLENTY OF INSOLATION. DESPITE THIS EARLY AFTERNOON
TEMPERATURES RUNNING A FEW DEGREES COOLER THAN YESTERDAY`S
READINGS WITH GOING MAX TEMP FORECAST STILL ON TRACK. WILL LET
HEAT WARNING RIDE UNTIL EXPIRATION. LATEST HIRES GUIDANCE IN
GENERAL AGREEMENT WITH MAJORITY OF CONVECTION BREAKING OUT EARLY
THIS AFTERNOON ACROSS THE SIERRA...SOUTH OF LAKE TAHOE...AND
SPREADING NORTH AND EAST DURING THE AFTERNOON AND EVENING HOURS.
A FEW STRONG STORMS POSSIBLE WITH LIKELY HEAVY DOWNPOURS IN ANY
STORM GIVEN MODERATE INSTABILITY AND HIGH PWAT VALUES IN EXCESS OF
1 INCH. MODELS STILL HINTING AT A FEW SHOWERS AND THUNDERSTORMS
MAKING A RUN DOWN INTO THE VALLEY LATER THIS EVENING AND TONIGHT
SO CAN`T RULE IT OUT. TO ACCOUNT FOR THIS HAVE ADDED A SLIGHT
CHANCE TO PORTIONS OF THE VALLEY AFTER 00Z. NOT EXPECTING
WIDESPREAD ACTIVITY BUT HARD TO PINPOINT ANY ONE LOCATION VERSUS
ANOTHER AT THIS POINT.

ADDITIONAL COOLING IS EXPECTED FRIDAY THROUGH THE WEEKEND AS HIGH
PRESSURE RIDGE WEAKENS. NORTHERN VALLEY WILL LIKELY STILL BE IN
THE LOW 100S BUT REST OF THE VALLEY EXPECTED TO BE IN THE 90S.
ONSHORE FLOW WILL STRENGTH KEEPING DELTA INFLUENCED AREAS COOLER
WITH NEAR NORMAL TEMPERATURES. THE CHANCE FOR MOUNTAIN
THUNDERSTORMS WILL CONTINUE EACH AFTERNOON AND EVENING WITH DRY
WEATHER AND PARTLY CLOUDY SKIES EXPECTED IN THE VALLEY. CEO

&&
.EXTENDED DISCUSSION (MONDAY THROUGH THURSDAY)

NORCAL WILL BE SANDWICHED BETWEEN A LOW OVER THE EASTERN PACIFIC
OCEAN AND A RIDGE OVER THE GREAT BASIN THROUGH MUCH OF WEEK. GFS
AND EC ARE SIMILAR IN SHOWING THE UPPER LOW SLOWLY DRIFTING EAST-
NORTHEAST TOWARD THE NORCAL COAST THROUGHOUT THE WEEK. THE THREAT
OF THUNDERSTORMS EXISTS OVER THE MOUNTAINS THROUGH THE EXTENDED
WITH TUESDAY HAVING THE LEAST AREAL COVERAGE. AS THE LOW DRIFTS
CLOSER, THE MORE LIKELY THE CHANCE OF THUNDERSTORM ACTIVITY. THE
MODELS HAVE A DIFFICULT TIME FORECASTING THE TRACK OF THESE
OFFSHORE UPPER LOWS, SO THE AREA OF THUNDERSTORMS MAY CHANGE AS
THE EXTENDED DRAWS CLOSER.

HIGH TEMPERATURES WILL HOLD STEADY THROUGH THE EXTENDED FORECAST
PERIOD AS NORCAL REMAINS BETWEEN THE UPPER LOW AND HIGH. MAX
TEMPERATURES EXPECTED MAINLY IN THE 90S FOR THE CENTRAL VALLEY
(TRIPLE DIGITS FOR THE NORTHERN SACRAMENTO VALLEY), 80S FOR THE
DELTA AND FOOTHILLS, AND 70S FOR THE MOUNTAINS...WHICH WILL ALL
BE NEAR AVERAGE.            JCLAPP

&&

.AVIATION...

PREDOMINANTLY VFR CONDITIONS TODAY, EXCEPT FOR POTENTIAL MVFR
IN MTN T-STORMS. EXPECT STANDARD DELTA BREEZE WINDS INTO THIS
EVENING AND BREEZY LOWER BOUNDARY LAYER WINDS (UP TO 2K FT AGL)
ACROSS MTNS THIS AFTN.    JCLAPP
&&

.STO WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING UNTIL 7 PM PDT THIS EVENING FOR MOUNTAINS
SOUTHWESTERN SHASTA COUNTY TO NORTHERN LAKE COUNTY-NORTHERN
SACRAMENTO VALLEY-SHASTA LAKE AREA / NORTHERN SHASTA COUNTY.

&&

$$


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