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000
FXUS66 KSTO 150417
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
917 PM PDT TUE MAY 14 2013

.SHORT TERM DISCUSSION...

A PRETTY STRONG GRADIENT EXIST BETWEEN SFO-SAC AT 4.7 MB THIS
EVENING. WINDS ARE NOT THAT STRONG THROUGH THE DELTA CONSIDERING
THIS GRADIENT BUT THE SACRAMENTO AND NORTHERN SAN JOAQUIN HAVE
GOTTEN SOME DECENT WINDS THAT ARE CONTINUING THIS EVENING IN SOME
AREAS. TEMPERATURES FOR THE MOST PART HAVE BEEN COOLING OFF
FASTER THIS EVENING AND SHOULD END UP COOLING OFF SEVERAL
DEGREES MORE THAN THIS MORNINGS LOWS.

A STRONGER LOW PRESSURE SYSTEM OVER THE PACIFIC WILL BRING ONLY
SLIGHT SYNOPTIC COOLING AHEAD OF THE SYSTEM TO THE REGION FOR
WEDNESDAY. THE FIRST WAVE ASSOCIATED WITH THIS LOW PRESSURE AREA
WILL MOVE THROUGH THE NORTH ON WEDNESDAY AND MAY BRING SOME LIGHT
AMOUNTS OF PRECIPITATION JUST NORTH OF SHASTA COUNTY. AT THE VERY
LEAST LOOK FOR AN INCREASE IN CLOUD COVER OVER THE NORTH DURING
THE DAY AND DURING THE EVENING FURTHER SOUTH.

THE MODELS CONTINUE TO SHOW A DEEPER STRONGER AND MORE MOIST
SYSTEM WITH THE TROUGH FOR THURSDAY. ON THURSDAY THE LOW WILL
DEEPEN OVER THE REGION AND THERE SHOULD BE PLENTY OF CLOUD COVER
WITH THE TROUGH AXIS REMAINING ALONG THE COAST DURING MOST OF THE
DAY. AS IT MOVES INLAND LATE THURSDAY AND THURSDAY EVENING THAT
SHOULD BE THE BEST TIME FOR SHOWERS INTO THE VALLEY. CURRENTLY THE
PROFILES ARE VERY MOIST AND DO NOT SUPPORT THUNDERSTORM ACTIVITY
BUT IF THERE IS SOME CLEARING AND TEMPERATURES GET A LITTLE BE
WARMER THAN WE MIGHT BE ABLE TO SEE A FEW THUNDERSTORMS OVER THE
INTERIOR. SNOW LEVELS SHOULD LOWER THURSDAY NIGHT BUT STILL REMAIN
HIGH ABOVE 7500 TO 8000 FEET. AN INCH OR TWO OF SNOW MAY BE
POSSIBLE OVER SOME OF THE HIGHER ELEVATIONS BY FRIDAY MORNING. FOR
THE VALLEY ANYWHERE FROM A TRACE TO AROUND A TENTH OF AN INCH
LOOKS POSSIBLE WHILE MANY MOUNTAIN AREA COULD GET BETWEEN A
QUARTER TO A HALF AN INCH OF RAINFALL...ESPECIALLY NORTH OF
HIGHWAY 50 FROM THIS SYSTEM.


.EXTENDED DISCUSSION (SATURDAY THROUGH TUESDAY)

A LITTLE MORE SPREAD AND A LITTLE MORE TROFFING IN THE ECMWF MODEL
ON SAT RESULTS IN A LITTLE MORE UNCERTAINTY IN THE FORECAST FOR THE
NRN ZONES...OTHERWISE WARMING AND DRYING OCCURS THROUGH THE WEEKEND.
EARLY NEXT WEEK (MON/TUE) A DEEP CLOSED LOW IS FORECAST TO DEVELOP
OFF THE B.C. OR PAC NW COAST DEPENDING ON THE MODEL...WITH THE GFS
THE FARTHEST SOUTH ON TUE. AFTER A WARM WEEKEND CONTINUING INTO
MON...A COOLING TREND IS EXPECTED ON TUE AS LOWERING HEIGHTS AND
INCREASING ONSHORE FLOW RESULT IN DEEP SYNOPTIC COOLING ON TUE. WE
HAVE BLENDED THE MAX TEMPS FOR TUE...WITH THE POSSIBILITY FOR
FURTHER COOLING IF THE PATTERN HOLDS. OTHERWISE...THE PRECIP FROM
THIS DEEP CLOSED LOW IS FORECAST TO MAINLY STAY N OF NORCAL WITH
STRONG AND DRY WSWLY FLOW INTO OUR CWA RAISING FIRE WX CONCERNS
DUE TO STRENGTHENING WINDS OVER THE HIGHER TERRAIN AND DRY/DRYING
FUELS...ALBEIT THERE WILL BE SOME RELIEF FROM THE COOLER TEMPS.
   JHM



&&

.AVIATION...

MAINLY VFR SKC CONDITIONS OVER TAF SITES WITH INCREASE IN HIGH CLOUD
COVER AFT 12Z WED WITH BASES ABV 15 KFT THRU 00Z THU.  DELTA
BREEZE FORECAST TO BE 15-25 KTS THROUGH THE CARQUINEZ STRAIT THIS
EVENING AND OVERNITE...AND INTO THE INTERIOR VALLEY 5-15 KTS
OVERNITE. MARINE LAYER IS WELL MIXED OUT OFF THE COAST...AND ANY
STRATUS THAT FORMS IS EXPECTED TO BE CONFINED TO THE COAST OR
COASTAL VALLEYS.

&&

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

$$