Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 261540
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
840 AM PDT SUN JUL 26 2015

.SYNOPSIS...
DRY WEATHER CONTINUES ACROSS THE AREA EXCEPT FOR A SLIGHT CHANCE OF
SHOWERS OVER NORTHERN SHASTA COUNTY LATE TODAY AND TONIGHT. TEMPS
AROUND AVERAGE TODAY, THEN CLIMBING TO WELL ABOVE NORMAL DURING THE
WEEK WITH TRIPLE DIGIT HEAT RETURNING TO THE VALLEY.

&&

.DISCUSSION... LITTLE CHANGE IN THE WEATHER PATTERN COMPARED TO 24
HOURS AGO. SKIES ARE CLEAR ACROSS INTERIOR NORCAL THIS MORNING
EXCEPT FOR AREAS OF SMOKE NEAR THE LOWELL WILDFIRE EAST OF GRASS
VALLEY DRAINING DOWN INTO THE EASTERN EDGE OF THE SACRAMENTO VALLEY
NEAR YUBA CITY. TEMPERATURES AND SURFACE GRADIENTS ARE NEARLY
IDENTICAL TO 24 HOURS AGO.

VERY SIMILAR DAY TO SATURDAY TEMPERATURE AND WIND-WISE EXPECTED
ACROSS THE REGION TODAY. SATELLITE IMAGERY SHOWS CLOUDS ASSOCIATED
WITH A SHORT-WAVE OFF THE OREGON COAST THIS MORNING. THIS FEATURE
WILL BRUSH ACROSS FAR NORTHERN CALIFORNIA LATER TODAY AND MAY
PROVIDE ENOUGH LIFT TO SPARK A FEW SHOWERS AND THUNDERSTORMS ACROSS
THE NORTHERN MOUNTAINS INTO THIS EVENING.

OTHERWISE, THE MAIN WEATHER STORY CONTINUES TO BE THE BIG WARMUP
THAT WILL BEGIN DURING THE WEEK AS HIGH PRESSURE BUILDS ACROSS THE
REGION. NO UPDATES.

&&

.PREVIOUS DISCUSSION...QUIET MORNING UNDER LIGHT SOUTHWEST FLOW
ALOFT. THE MARINE LAYER CONTINUES TO DEEPEN AS AN UPPER LEVEL TROUGH
DIGS INTO THE EASTERN PACIFIC. FORT ORD PROFILER SHOWING MARINE
LAYER AT ABOUT 1600 FEET THIS MORNING AND SOME COASTAL STRATUS SEEMS
TO BE MAKING IT INTO THE WESTERN DELTA SO FAR THIS MORNING.
OTHERWISE...FAIR SKIES PREVAIL OVER NORTHERN CALIFORNIA.
TEMPERATURES THIS MORNING RUNNING SIMILAR TO 24 HOURS AGO AND SHOULD
SEE DAYTIME HIGHS SIMILAR TO YESTERDAY AS WELL. THERE MAY BE A
SLIGHT COOLING ESPECIALLY NORTHERN PORTIONS OF THE CWA AS THE UPPER
TROUGH APPROACHES. THIS TROUGH MAY GENERATE ENOUGH INSTABILITY FOR A
FEW SHOWERS LATE THIS AFTERNOON OVER FAR NORTHWEST SHASTA COUNTY.
SMOKE WILL LIKELY IMPACT SOME AREAS EAST OF THE LOWELL FIRE AS
SOUTHWEST FLOW AHEAD OF THE OFFSHORE TROUGH BECOMES ESTABLISHED
TODAY. OTHERWISE FAIR SKIES WILL CONTINUE FOR MOST AREAS. UPPER
TROUGH PASSAGE THROUGH THE PACIFIC NORTHWEST WILL BRING A THREAT OF
SHOWERS ACROSS THE NORTHERN PORTIONS OF SHASTA COUNTY THIS EVENING
BUT THIS WILL BE ABOUT THE EXTENT OF ITS IMPACT IN THE SHORT TERM.
AS THE TROUGH SHIFTS EAST OF THE STATE MONDAY MORNING HIGH PRESSURE
ALOFT BEGINS TO MOVE INLAND OVER THE WEST COAST. THIS WILL BRING THE
BEGINNING OF A WARMING AND DRYING TREND EXPECTED TO LAST THROUGH MID
WEEK. SURFACE HIGH PRESSURE PUSHING IN BEHIND THE TROUGH AND INTO
THE PACIFIC NORTHWEST WILL PRODUCE A MODERATE NORTHERLY SURFACE
GRADIENT ACROSS NORTHERN CALIFORNIA BY EARLY MONDAY. THIS DRY
NORTHERLY FLOW WILL BRING MUCH LOWER HUMIDITY BY MONDAY AFTERNOON
FOR INCREASED FIRE DANGER. BUILDING HIGH PRESSURE WILL BRING A WARM
UP TO RIGHT AROUND NORMAL ON MONDAY AFTERNOON WITH MORE WARMING
TUESDAY AND WEDNESDAY AS UPPER RIDGING BUILDS OVER THE WEST COAST.
HIGH TEMPERATURES ON TUESDAY WILL BE SEVERAL DEGREES ABOVE NORMAL
WITH A LITTLE MORE WARMING STILL IN STORE FOR WEDNESDAY. HIGHS IN
THE VALLEY WILL LIKELY TOP 100 MOST LOCATIONS ON TUESDAY AND 105
MOST VALLEY BOTTOM LOCATIONS ON WEDNESDAY.

&&

.EXTENDED DISCUSSION (THURSDAY THROUGH SUNDAY)...HIGH PRESSURE WILL
MAINTAIN ABOVE NORMAL TEMPERATURES IN THE EXTENDED PERIOD, ALTHOUGH,
THERE WILL BE A GRADUAL COOLING TREND FROM THURSDAY INTO THE WEEKEND.

HIGH PRESSURE CELL OVER THE GREAT BASIN AND EXTENDING INTO NORCAL
WILL STILL BE FAIRLY STRONG ON THURSDAY...DAYTIME HIGHS MEASURE
AROUND 5 TO 11 DEGREES ABOVE NORMAL. WIDESPREAD TRIPLE DIGIT HEAT
FORECAST IN THE VALLEY WITH PEAK HIGHS RANGING 100-110 (WARMEST IN
THE REDDING/RED BLUFF VICINITY). THE HIGH WEAKENS INTO THE WEEKEND
AS A TROUGH DIGS SOUTHWARD OVER THE EASTERN PACIFIC OCEAN. BY
SUNDAY, DAYTIME HIGHS WILL ONLY BE ABOUT 1-5 DEGREES ABOVE NORMAL.

THE OTHER INTERESTING FACTOR WITH THIS HIGH IS THAT MOISTURE
WRAPPING AROUND THE HIGH COULD BRING THUNDERSTORMS AND/OR SHOWERS TO
OUR REGION, MAINLY LIMITED TO THE MOUNTAINS. MODELS ARE INDICATING
THAT BEST CHANCES FOR MOUNTAIN SHOWER ACTIVITY WILL BE FRI-SUN. JBB

&&

.AVIATION... VFR CONDS CONT NEXT 24 HOURS EXC MVFR AND LCL IFR CONDS
VCNTY LOWELL FIRE NEAR KGOO. VALLEY WINDS UNDER 10 KTS EXC 10-15 KTS
23Z-04Z MON. SW WINDS 15-25 KTS CONT VCNTY CARQ STRAIT AND W DELTA,
STRONGEST 00Z-06Z MON.

&&

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

&&

$$


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