Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 010448
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
948 PM PDT TUE JUN 30 2015

.SYNOPSIS...
VERY HOT WEATHER CONTINUES ACROSS THE REGION THIS WEEK. SIERRA
THUNDERSTORMS THROUGHOUT THE WEEK WITH SHOWERS OR SPRINKLES
POSSIBLE IN PORTIONS OF THE VALLEY THURSDAY AND FRIDAY.

&&

.DISCUSSION...
THE HEAT WILL CONTINUE FOR AT LEAST ONE MORE DAY FOR THE
SACRAMENTO REGION WHILE IT WILL TAKE UNTIL FRIDAY BEFORE THE NORTH
END OF THE VALLEY BEGINS TO SEE A DECENT COOLING TREND. THE DELTA
BREEZE WILL NOT HAVE MUCH OF AN IMPACT UNTIL WEDNESDAY NIGHT INTO
THURSDAY WHEN IT IS EXPECTED TO START TO INCREASE. WINDS SHOULD
REMAIN UP THROUGHOUT THURSDAY TO HELP BRING SOME COOLER AIR FOR
THE SACRAMENTO REGION. WE SHOULD ALSO SEE SOME CLOUD COVER DURING
THE DAY WHICH SHOULD HELP AS WELL. UNFORTUNATELY THE CLOUD COVER
WILL HELP TO KEEP THE OVERNIGHT LOWS UP TONIGHT AND AGAIN THURSDAY
NIGHT FOR MOST LOCATIONS ABSENT THE DELTA INFLUENCE.

THE OTHER THING OF CONCERN WILL BE WITH THE INCREASED MONSOONAL
MOISTURE AND INCREASE IN THUNDERSTORM POTENTIAL OVER THE NEXT
SEVERAL OF DAYS. FOR WEDNESDAY THE THUNDERSTORM ACTIVITY WILL
MAINLY STAY OVER THE CREST BUT ON THURSDAY AS THE CENTRAL PART OF
THE HIGH MIGRATES FROM NEAR THE 4-CORNERS AREA TO OVER NEVADA
THERE WILL BE AN INCREASED THREAT FOR SHOWERS AND THUNDERSTORMS
OVER THE INTERIOR FIRST FOR THE WESTERN SLOPES DURING THE DAY AND
THEN INTO THE CENTRAL VALLEY FOR THURSDAY NIGHT.

THE DOWNWARD TREND IN TEMPERATURES WILL CONTINUE FRIDAY ALONG WITH
CHANCES OF MOUNTAIN SHOWERS AND THUNDERSTORMS. SOME RESIDUAL
SHOWERS OR ISOLATED THUNDERSTORMS MAY LINGER OVER THE NORTH END
OF THE VALLEY FRIDAY MORNING BUT ANY ACTIVITY SHOULD MOVE NORTH
INTO THE MOUNTAINS BY LATE MORNING. CLOUD CLOVER ONCE AGAIN WILL
BE OUR FRIEND DURING THE DAY HELPING TO KEEP TEMPERATURES DOWN A
LITTLE.

&&
.EXTENDED DISCUSSION (SATURDAY THROUGH TUESDAY)

OVER THE WEEKEND, INTERIOR NORCAL IS SANDWICHED BETWEEN A FOUR
CORNERS UPPER HIGH AND AN OFFSHORE UPPER LOW. SOUTH TO SOUTHEAST
FLOW ALOFT WILL CONTINUE TO DRAW MONSOONAL MOISTURE INTO THE
AREA. MAIN INSTABILITY, AND THUS THREAT OF SHOWERS AND
THUNDERSTORMS, IS DEPICTED OVER THE MOUNTAINS IN THE AFTERNOONS
INTO EARLY EVENINGS. DRIER AND MORE STABLE SOUTHWEST FLOW ALOFT
DEVELOPS LATE SUNDAY INTO TUESDAY AS THE UPSTREAM UPPER LOW DRIFTS
NORTHWARD, SLIGHTLY CLOSER TO THE NORCAL COAST. AS A RESULT, THE
THREAT OF AFTERNOON DEEP MOIST CONVECTION SHIFTS EAST OF THE
SIERRA NEVADA CREST.

HIGH TEMPERATURES THROUGH THE EXTENDED FORECAST PERIOD WILL BE
COOLER. MAX READINGS WILL RANGE FROM THE MID 80S IN THE DELTA TO
AROUND 100 IN THE NORTHERN SACRAMENTO VALLEY, WITH UPPER 70S TO
AROUND 90 FOR THE MOUNTAINS AND FOOTHILLS.     JCLAPP

&&

.AVIATION...

UPPER HIGH OVER ROCKIES EXTENDS OVER NORCAL AND CONTINUES
SOUTHERLY FLOW ALOFT AND HOT TEMPS. ISOLD TSTM OVER SIERRA NEVADA
BETWEEN 22Z- 02Z. AFTERNOON DENSITY ALTITUDES MAY BE HIGH WED/THU.
JCLAPP
&&

.STO WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING FROM 2 PM WEDNESDAY TO 8 AM PDT FRIDAY
FOR CENTRAL SACRAMENTO VALLEY-CLEAR LAKE/SOUTHERN LAKE COUNTY-
MOUNTAINS SOUTHWESTERN SHASTA COUNTY TO NORTHERN LAKE COUNTY-
NORTHEAST FOOTHILLS/SACRAMENTO VALLEY-NORTHERN SACRAMENTO VALLEY-
SHASTA LAKE AREA / NORTHERN SHASTA COUNTY.

&&

$$



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