Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 030508
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
1005 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...

SHORT WAVE ENERGY ALONG THE SRN CA/SRN NV BORDER MOVING NWWD GIVEN
THE SELY FLOW AROUND THE 4-CORNERS HIGH WAS FOCUSING STORM ACTIVITY
OVER THE SIERNEV. NOW THAT DIFFERENTIAL HEATING HAS SUBSIDED...STORM
ACTIVITY IS WINDING DOWN BUT AN AREA OF MOSTLY RAIN SHOWERS WILL
AFFECT THE NRN PORTION OF THE CWA...NORTH OF I-80...FOR MUCH OF THE
REST OF THE NIGHT. PERHAPS AN ISOLATED TRW WILL BE EMBEDDED WITHIN
THE LARGER AREA OF SHOWERS.

STRONG DELTA BREEZE BRINGING COOLING TO THE DELTA INFLUENCED AREAS
OF SOME 6-15 DEGREES...BUT NOT QUITE BRINGING COOLING TO THE NRN SAC
VLY WHERE TEMPS ARE RUNNING SIMILAR TO WED. RDD-SAC GRADIENT IS
BEGINNING TO WANE...SO SHOULD SEE THE SLY BREEZE WEAKEN ACROSS THE
NRN PORTION OF THE VALLEY OVERNIGHT...WHILE THE ONSHORE GRADIENT
WILL LIKELY CONTINUE THE DELTA BREEZE FOR THE SRN SAC VLY FOR MUCH
OF THE NIGHT.   JHM

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...NONE.


&&

$$


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