Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 281600
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
900 AM PDT SUN JUN 28 2015

.SYNOPSIS...
CONTINUED MILD TODAY, THEN HEAT RETURNS DURING THE
WEEK. SOME SIERRA THUNDERSTORMS THROUGHOUT THE WEEK.

&&

.DISCUSSION... AREA OF SHOWERS ALONG THE MOISTURE BAND IS MOVING
NORTHWARD AND WILL BE MOSTLY OUT OF THE FORECAST AREA LATER THIS
MORNING. TEMPERATURES THIS MORNING ARE GENERALLY WITHIN A FEW
DEGREES OF READINGS 24 HOURS AGO.

RELATIVELY MILD TEMPERATURES WILL CONTINUE ACROSS THE AREA TODAY
WITH ONSHORE FLOW PERSISTING. THE CLOUD BAND OVER MUCH OF THE AREA
THIS MORNING WILL CONTINUE TO SHIFT A LITTLE FURTHER TO THE NORTH
AND EAST WITH TIME ALLOWING FOR GREATER SUNSHINE ACROSS MOST OF THE
REGION BY NOON. STILL LOOKING LIKE ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE LATER THIS AFTERNOON, MAINLY ALONG
AND EAST OF THE SIERRA/CASCADE CREST.

NO UPDATES.

&&

.PREVIOUS DISCUSSION (TODAY THROUGH WEDNESDAY)... A WEAK DISTURBANCE
MOVING NORTHWARD EAST OF THE CLOSED LOW IS ENHANCING CLOUDINESS OVER
NORCAL THIS MORNING. HOWEVER, MOST OF THE CLOUD BASES ARE ABOVE 15K
FT AND WE COULDN`T FIND ANY WEATHER STATIONS REPORTING ANY
MEASURABLE RAINFALL.

THE BEST CHANCE FOR THUNDERSTORMS TODAY WOULD BE LATER THIS MORNING
INTO AFTERNOON AS THE WAVE MOVES OVER THE AREA, AND ANY ADDED
AFTERNOON INSTABILITY DUE TO SURFACE HEATING WILL HELP. HOWEVER, NOT
SURE HOW MUCH SURFACE HEATING WILL OCCUR WITH THE CLOUDINESS ABOUT.
IN THE END, NOT SO SURE WE`LL SEE THE THUNDERSTORM ACTIVITY TODAY
THAT WE HAD ANTICIPATED, AS THE TRIGGER (INSTABILITY) IS JUST NOT
THAT SIGNIFICANT. THEREFORE, WE DISCONTINUED THE RED FLAG WARNING
FOR THUNDERSTORMS AND ABUNDANT LIGHTNING.

THE CHANCE OF AFTERNOON SIERRA THUNDERSTORM ACTIVITY MAINLY
SOUTHWARD OF I-80 LINGERS MONDAY THROUGH WEDNESDAY AS THE GREAT
BASIN HIGH BUILDS BACK INTO THE AREA. TEMPERATURES ARE FORECAST TO
BEGIN WARMING UP AGAIN ON MONDAY. BY TUESDAY AND WEDNESDAY, VERY HOT
WEATHER IS FORECAST TO RETURN TO NORCAL WITH READINGS THROUGH MUCH
OF THE CENTRAL VALLEY EXPECTED TO RETURN TO THE 100 TO 110 DEGREE
RANGE. JCLAPP

&&

.EXTENDED DISCUSSION (THURSDAY THROUGH SUNDAY)...UPPER LEVEL HIGH
PRESSURE SYSTEM STRETCHING FROM THE FOUR CORNERS REGION TO NORCAL
MOVES LITTLE THROUGH THE EXTENDED PERIOD. SOUTHEAST FLOW ALOFT WILL
CONTINUE TO FEED SUB-TROPICAL MOISTURE AND INSTABILITY NORTHWESTWARD
INTO THE STATE. WITH SOME OROGRAPHICS...NORTHERN SIERRA SHOULD SEE
AT LEAST A CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS EACH DAY.
FARTHER NORTH UP THE SIERRA CASCADE RANGE OR OVER THE NORTHERN
MOUNTAINS WILL LIKELY HAVE TO RELY ON SOME SORT OF SMALL SCALE
DISTURBANCE ROTATING NORTHWARD AROUND THE BACK SIDE OF THE LOW.
THESE SMALL SCALE DISTURBANCES ARE NOT LIKELY TO BE MODELED WELL
THIS FAR OUT SO DIFFICULT TO PREDICT WHEN THUNDERSTORMS MIGHT IMPACT
THE MOUNTAIN AREAS OUTSIDE OF THE SIERRA. FOR NOW...HAVE KEPT SLIGHT
THREAT OF HIGHEST ELEVATION THUNDERSTORMS IN OVER THE SHASTA COUNTY
MOUNTAINS TO COVER THE SLIGHT POSSIBILITY OF ONE OF THESE SHORTWAVES
MOVING THROUGH EXCEPT ON THURSDAY WHERE MODELS HAVE UPPER RIDGE MORE
CENTERED OVER THE WESTERN GREAT BASIN AND FORECAST AREA.

WITH RIDGE CENTERED THE MOST OVER NORCAL ON THURSDAY...THIS LOOKS TO
BE THE WARMEST DAY WITH A SLIGHT COOLING THROUGH THE WEEKEND AS THE
RIDGE SLIPS SLIGHTLY EASTWARD IN RESPONSE TO THE PASSAGE OF A
FRONTAL SYSTEM WELL TO THE NORTH. EVEN WITH THE COOLING...DAILY HIGH
TEMPERATURES WILL REMAIN WELL ABOVE NORMAL. EXCEPT FOR THE
DELTA...WINDS LOOK TO REMAIN FAIRLY LIGHT THROUGH THE EXTENDED
PERIOD UNDER THE RIDGE.

&&

.AVIATION...
SOUTHERLY FLOW ALOFT AS NORCAL REMAINS BETWEEN HIGH PRESSURE OVER
THE FOUR CORNERS AREA AND A LOW OFFSHORE. VFR CONDITIONS OVER THE
INTERIOR NEXT 24 HOURS. SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS POSSIBLE OVER MOUNTAINS WITH ASSOCIATED STRONG GUSTY
SURFACE WINDS.

&&

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

&&

$$


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