Severe Thunderstorm Warning 14, NWS Sacramento, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
1006 AM PDT WED JUL 8 2015

.SYNOPSIS...
THUNDERSTORMS TODAY THROUGH FRIDAY WITH HEAVY RAIN IN MOUNTAINS,
AND POTENTIAL FLASHING FLOODING OVER MOUNTAINS TODAY.

&&
.DISCUSSION...
SHOWERS AND THUNDERSTORMS WILL GET STARTED EARLY TODAY WITH
MOUNTAIN INITIATION TIME AROUND 11 AM. HEAVY RAINFALL IS POSSIBLE
AND FLASH FLOOD WATCH IS IN EFFECT FOR THE MOUNTAINS. CURRENT
FORECAST IS ON TRACK AND NO MORNING UPDATE WILL BE NEEDED.

.PREVIOUS DISCUSSION (TODAY THROUGH SATURDAY)...
THE UPPER LOW IS ROUGHLY 200 MILES WEST OF SAN FRANCISCO. THE LOW
ENLONGATED SLIGHTLY WEST TO EAST THROUGH CENTRAL CA WITH THE
NORTHEASTERN QUADRANT BEING THE MOST UNSTABLE. CONVECTION AND
ENHANCED CLOUD TOPS ARE PRESENT ON INFRARED SATELLITE FROM EASTERN
NV THROUGH EXTREME NORTHERN CA AS OF 3AM. THE LOW WILL PUSH
ONSHORE BETWEEN SAN FRAN AND MONTEREY THIS EVENING AND IT WILL
CONTINUE TO HAVE SOME ELEVATED INSTABILITY WITH IT AS WELL AS SOME
LIFT. ANOMALY DATA SHOWING SOME PRETTY HEFTY 30 YEAR RETURN VALUES
OF PRECIPITABLE WATER IN FAR NORTHER CALIFORNIA AND 5 TO 10 YEAR
INTERVAL RETURNS ACROSS SIERRA AND SHASTA COUNTY. SO EXPECT SOME
PRETTY HEAVY RAIN THIS AFTERNOON AND EVENING ACROSS HIGHER SIERRA
AND INTO SHASTA COUNTY. MOST OF SIERRA RAINFALL SOUTHWARD OF I-80
WILL BE NEAR AND EAST OF THE CREST WITH THE SOUTHERLY STEERING
WINDS, BUT FARTHER NORTH THE SOUTHEAST TO EAST STEERING FLOW WILL
DEFINITELY BRING HEAVY RAIN INTO WEST SIDE OF SIERRA. AS A RESULT
WE HAVE ISSUED A FLASH FLOOD WATCH FOR THE HIGHER SIERRA AND MUCH
OF SHASTA COUNTY THIS AFTERNOON AND EVENING.

THURSDAY EASTERLY FLOW ALOFT WILL CONTINUE TO BRING A RISK OF
THUNDERSTORMS TO MOUNTAINS AND ALSO TO NORTHERN SACRAMENTO VALLEY
IN REDDING AND RED BLUFF AREAS. THUNDERSTORMS THAT DO OCCUR WILL
HAVE HEAVY RAIN ONCE AGAIN, BUT HELD BACK FROM ISSUING ANY HAZARD
PRODUCTS DUE THE CURRENT WATCH IN PLACE. THIS EVENING OR TONIGHT, WE
WILL NEED TO ADDRESS THE FLASH FLOOD WATCH ISSUE FOR THURSDAY.

THE LOW MOVES THROUGH THE AREA FRIDAY, BUT STILL EXPECT MOUNTAIN
THUNDERSTORMS. SATURDAY, GENERAL SOUTHWEST FLOW ALOFT SHOULD DRY
THINGS OUT. ANYWAY, TEMPERATURES WILL WARM UP A BIT WITH THE
CLEARER SKY.   JCLAPP

&&
.EXTENDED DISCUSSION (SUNDAY THROUGH WEDNESDAY)

FROM SUNDAY INTO WEDNESDAY, NORCAL WILL BE UNDER THE INFLUENCE OF
A BROAD TROUGHING PATTERN WHILE HIGH PRESSURE LINGERS OVER THE
DESERT SOUTHWEST. SOUTHWEST FLOW IN THE TROUGH WILL BE FAIRLY DRY.
A FEW MOUNTAIN SHOWERS MAY LINGER ON SUNDAY, OTHERWISE, EXPECT
INTERIOR NORCAL TO BE DRY NEXT WEEK. TEMPERATURES WILL STILL BE
SLIGHTLY BELOW NORMAL ON SUNDAY, BUT AS THE TROUGH WEAKENS NEXT
WEEK, THERE WILL BE A WARMING TREND. BY WEDNESDAY, DAYTIME HIGHS
WILL BE A FEW DEGREES ABOVE NORMAL.  JBB

&&

.AVIATION...

ONSHORE FLOW CONTINUES WITH SW WIND GUSTS 20-30 KT NEAR THE
DELTA. WINDS AT TAF SITES WILL GENERALLY BE LIGHT EXCEPT BETWEEN
21-06Z WITH WINDS 10-20 KTS FOR KSAC, KSMF, KMHR, KSAC. LOCAL
MVFR/IFR CONDITIONS ALSO POSSIBLE IN THUNDERSTORMS/SHOWERS THAT
DEVELOP THIS AFTERNOON AND EVENING. THUNDERSTORMS POSSIBLE IN THE
MOUNTAINS, FOOTHILLS, AND IN THE SACRAMENTO VALLEY NORTH OF
INTERSTATE 80. JBB

&&

.STO WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS EVENING FOR BURNEY BASIN /
EASTERN SHASTA COUNTY-NORTHEAST FOOTHILLS/SACRAMENTO VALLEY-
SHASTA LAKE AREA / NORTHERN SHASTA COUNTY-WEST SLOPE NORTHERN
SIERRA NEVADA-WESTERN PLUMAS COUNTY/LASSEN PARK.

&&

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SACRAMENTO CA
1211 PM PDT WED JUL 8 2015

CAZ068-069-082000-
WEST SLOPE NORTHERN SIERRA NEVADA CA-
WESTERN PLUMAS COUNTY/LASSEN PARK CA-
1211 PM PDT WED JUL 8 2015

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN PLUMAS AND
NORTHEASTERN SIERRA COUNTIES UNTIL 100 PM PDT...

AT 1210 PM PDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM
OVER BASSETTS...OR NEAR SIERRA CITY...MOVING NORTH AT 10 MPH.

HALF INCH HAIL AND WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH
THIS STORM.

LOCATIONS IMPACTED INCLUDE...
SIERRA CITY AND BASSETTS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM.
LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

&&

LAT...LON 3950 12045 3953 12059 3953 12074 3973 12077
      3972 12072 3971 12065 3971 12063 3962 12048
      3953 12044
TIME...MOT...LOC 1910Z 161DEG 9KT 3960 12058

CS

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SACRAMENTO CA
1213 PM PDT WED JUL 8 2015

CAZ069-082000-
WEST SLOPE NORTHERN SIERRA NEVADA CA-
1213 PM PDT WED JUL 8 2015

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN NEVADA COUNTY UNTIL
100 PM PDT...

AT 1213 PM PDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM
OVER SODA SPRINGS SKI AREA...OR OVER SODA SPRINGS...MOVING NORTHWEST
AT 15 MPH.

HALF INCH HAIL AND WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH
THIS STORM.

LOCATIONS IMPACTED INCLUDE...
SODA SPRINGS...KINGVALE...SODA SPRINGS SKI AREA AND MEADOW LAKE.

LAT...LON 3932 12049 3944 12060 3944 12037 3938 12036
      3934 12032 3932 12031
TIME...MOT...LOC 1913Z 155DEG 11KT 3934 12038

CS

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