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000
FXUS66 KSTO 231047
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
347 AM PDT THU MAY 23 2013

.DISCUSSION...
THE QUASI (NEAR) STATIONARY LOW IS STILL POSITIONED OVER THE
WASHINGTON/NRN OREGON AREA. THE MODELS ARE IN GOOD AGREEMENT WITH
A SHORT WAVE TROUGH AXIS MOVING THROUGH NRN CAL THIS MORNING. SO
FAR, THE SHORT WAVE TROUGH IS NOT ALL THAT IMPRESSIVE AS CLOUD
ENHANCEMENT IS NOT TAKING PLACE OVER NRN CAL, IN THE DIVERGENT
REGION OF THE TROUGH. HOWEVER, ENHANCEMENT MAY OCCUR LATE THIS
MORNING AND INTO AFTERNOON DUE TO INCREASED LOW LEVEL THERMAL
INSTABILITY AND OROGRAPHIC LIFTING EFFECTS OVER SHASTA COUNTY DOWN
INTO WRN PLUMAS. WE HAVE ISOLATED SHOWERS FOR THIS SAME REGION
BEGINNING AROUND NOON. THE INSTABILITY IS NOT VERY IMPRESSIVE IN
PART DUE TO CLOUD COVER, SO WE LEFT OUT THE MENTION OF
THUNDERSTORMS.

THIS PARENT QUASI STATIONARY LOW WILL BECOME OBLONG TODAY WITH
LESS CYCLONIC FLOW OVER NRN CAL FRIDAY. THIS TRANSLATES TO LESS
CLOUDS, NO SHOWER ACTIVITY, AND SLIGHTLY WARMER TEMPERATURES.

FURTHER OUT...SEVERAL MORE REINFORCING SHORT WAVE TROUGHS COME OFF THE
NE PACIFIC...ONE SATURDAY INTO SUNDAY THAT BRINGS ANOTHER CHANCE
OF SHOWER ACTIVITY TO THE NRN MOUNTAIN REGION...AND THE NEXT
COUPLE REINFORCING WAVES IMPACT MUCH OF THE REGION NEXT WEEK WITH
A CHANCE OF LIGHT SHOWER ACTIVITY. THE MODELS ARE DIGGING THESE
WAVES A BIT DEEPER INTO CENTRAL AND SRN CAL WITH INCREASED UPPER
LEVEL DYNAMICS AND COOL TEMPERATURES, BUT THE TIMING AND EXACT
PLACEMENT IS STILL A BIT SQUIRRELY AT THIS POINT.   JCLAPP


&&

.AVIATION...
VFR CONDITIONS CONTINUE NEXT 24 HOURS FOR INTERIOR NORCAL TAF
SITES. NORTH WINDS LESS THAN 15 KNOTS TODAY BECOMING VARIABLE TO
10 KNOTS AFTER ABOUT 03Z.

&&

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

&&

$$