Area Forecast Discussion
Issued by NWS Sacramento, CA

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000
FXUS66 KSTO 031554
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
854 AM PDT FRI JUL 3 2015

.SYNOPSIS...
NEAR TO ABOVE NORMAL TEMPERATURES ALONG WITH DAILY AFTERNOON
THUNDERSTORMS MAINLY OVER THE MOUNTAINS WILL CONTINUE FOR THE NEXT
WEEK.

&&

.DISCUSSION...
NORCAL REMAINS UNDER SOUTHEASTERLY FLOW ALOFT, BETWEEN A RIDGE OF
HIGH PRESSURE OVER THE GREAT BASIN, AND AN UPPER LOW WELL OFF THE
SOUTHERN CALIFORNIA COAST. A DECENT AMOUNT OF MOISTURE CONTINUES
TO STREAM INTO NORCAL, WITH DOPPLER RADAR DETECTING SOME SPRINKLES
ACROSS THE FAR NORTHERN MOUNTAINS, AND A FEW SHOWERS/THUNDERSTORMS
ACROSS THE SIERRA. CLOUD COVER KEPT OVERNIGHT LOWS FAIRLY WARM
ACROSS THE NORTH, WHILE A MODEST ONSHORE BREEZE HELPED TO COOL OFF
AREAS FARTHER SOUTH.

THE MAIN MOISTURE PLUME SHIFTS NORTHWARD TODAY, AND UPPER LEVEL
FLOW BECOMES MORE SOUTHERLY THIS AFTERNOON. BOTH OF THESE FACTORS
SHOULD DECREASE THE COVERAGE OF THUNDERSTORMS THIS AFTERNOON
COMPARED TO THE LAST FEW DAYS. STILL EXPECT SOME THUNDERSTORMS TO
FORM THIS AFTERNOON, MAINLY ALONG THE SIERRA CREST AND THE
NORTHERN MOUNTAINS. TEMPERATURES TODAY SHOULD BE GENERALLY COOLER
THAN YESTERDAY.

TEMPERATURES ARE EXPECTED TO VERY GRADUALLY COOL DOWN OVER THE
NEXT FEW DAYS AS THE AFOREMENTIONED UPPER LOW SLOWLY APPROACHES
THE COAST. MOUNTAIN THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE THE
NEXT SEVERAL DAYS. THE STEERING FLOW WILL GENERALLY FAVOR
MOUNTAINS ALONG AND EAST OF THE SIERRA CREST THROUGH AT LEAST
MONDAY.

DANG

&&
.EXTENDED DISCUSSION (TUESDAY THROUGH FRIDAY)

BOTH THE EC AND GFS SHOW THE EASTERN PACIFIC UPPER LOW STRADDLING
THE NORTHERN CA COASTLINE TUESDAY AND WEDNESDAY. MOISTURE WRAPPING
AROUND THE LOW WILL BRING SLIGHT CHANCE TO CHANCE OF SHOWERS AND
THUNDERSTORMS, MAINLY OVER THE MOUNTAINS. BY THURSDAY, THE EC
MOVES THE LOW EASTWARD ACROSS NORCAL UNTIL IT WEAKENS AND LIFTS
NORTHEASTWARD ON FRIDAY. THE 06Z GFS ALSO HAS THE LOW MOVING
ACROSS NORCAL ON THURSDAY, BUT TRACKING A BIT SLOWER AND MAINTAINING
BETTER STRUCTURE. HAVE KEPT A FEW AREAS OF POSSIBLE SHOWERS FOR
THURSDAY, BUT TRENDED DRIER FOR FRIDAY.

AS STATED IN THE PRIOR DISCUSSION: THE MODELS HAVE A DIFFICULT
TIME FORECASTING THE TRACK OF THESE OFFSHORE UPPER LOWS, SO THE
AREA OF THUNDERSTORMS MAY CHANGE AS THE EXTENDED PERIOD DRAWS
CLOSER. (JCLAPP)

HIGH TEMPERATURES WILL REMAIN NEAR TO BELOW NORMAL FROM TUES INTO
FRIDAY AS THE LOW IMPACTS NORCAL. MAX TEMPERATURES TUESDAY EXPECTED
MAINLY IN THE 90S FOR THE CENTRAL VALLEY, 80S FOR THE DELTA AND
FOOTHILLS, AND 70S FOR THE MOUNTAINS...WHICH IS NEAR NORMAL.
DAYTIME HIGHS WILL BE 2-7 DEGREES BELOW NORMAL WEDNESDAY-FRIDAY
AS THAT LOW MOVES ACROSS NORCAL.  JBB


&&

.AVIATION...

PREDOMINANTLY VFR CONDITIONS TODAY, EXCEPT FOR POTENTIAL MVFR
IN MOUNTAIN THUNDERSTORMS. DELTA BREEZE WINDS STILL GOING STRONG
THIS MORNING WITH SPEEDS 20-30 KTS...EXPECT THEM TO WEAKEN AFTER
14Z BECOMING 10-20 KTS, THEN RE-STRENGTHEN AGAIN AFTER 00Z THIS
AFTERNOON. SURFACE WINDS AT TAF SITES WILL BE ONSHORE FLOW UP TO
12 KTS WITH OCCASIONAL GUSTS UP TO 18 KTS THIS AFTERNOON WHEN THE
DELTA BREEZE INCREASES.  JBB
&&

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

$$



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