High Wind in Washington, January 6, 2010

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
845 AM PST WED JAN 6 2010

.SYNOPSIS...STRONG HIGH PRESSURE OVER BRITISH COLUMBIA WILL SHIFT
SOUTHEAST THROUGH TONIGHT PROVIDING DRYING OFFSHORE FLOW.  A WEAK
FRONT WILL CONTINUE TO DISSIPATE AS IT MOVES ONSHORE TODAY. DRY AIR
WILL SETTLE OVER THE REGION TONIGHT AND THURSDAY...AND THE UPPER
LEVEL RIDGE ALONG THE WEST COAST WILL STRENGTHEN A BIT. A COUPLE OF
WEAK FRONTAL SYSTEMS WILL INCREASE THE CHANCE FOR RAIN TOWARD THE
END OF THE WEEK.

&&

.SHORT TERM...UPPER RIDGE AND OFFSHORE FLOW MADE QUICK WORK OF THE
LATEST WEAK FNTL SYS AND A PARTLY CLOUDY AND MILD DAY IS ON TAP FOR
WRN WA WITH MAYBE A SPRINKLE NEAR THE COAST OR OVER THE OLYMPICS.
THE GRADIENT GIVING THE NE FRASER WINDS WILL EASE TODAY BUT THE
CROSS CASCADE GRADIENT WILL PEAK...SO THERE IS A CHANCE THAT EVEN AS
THE WIND ADVISORY EXPIRES FOR WRN WHATCOM LATE THIS MORNING ONE WILL
GO UP FOR THE GAP EASTERLY WINDS WEST OF THE CASCADE PASSES. SKIES
PARTLY CLOUDY TONIGHT...COOLER IN THE CALM AREAS WITH FROST...AND
THEN AT LEAST A PARTLY SUNNY DAY ON TAP FOR THURSDAY WITH A DRY AIR
MASS AND UPPER RIDGE. ON FRIDAY THE CHANCE OF RAIN INCREASES AS A
WEAK FNTL SYS REACHES WRN WA...UPPER HEIGHTS DO NOT FALL A GREAT
DEAL THRU SAT AND THE LATEST GFS KEEPS MOST OF THE RAIN THRU SAT ON
THE COAST AND OLYMPICS. 19

.LONG TERM...THE PACIFIC NW WILL BE ON THE EASTERN EDGE OF A PARADE
OF WEATHER SYSTEMS THAT WILL BE ROLLING ACROSS THE PACIFIC AND
DECAYING AS THEY COME ONSHORE.  NONE OF THESE SYSTEMS ARE EXPECTED
TO BE STRONG OR OVERLY HEAVY RAIN PRODUCERS...BUT THEY WILL BE
ARRIVING EVERY DAY AND A HALF OR SO.  WHILE CONFIDENCE IS HIGH THAT
WE WILL BE AFFECTED BY SEVERAL SYSTEMS THROUGH THIS TIME
PERIOD...WITH HOW THE MODELS HAVE BEEN DEALING WITH THIS FLOW
PATTERN...CONFIDENCE IS RATHER LOW IN THE DETAILS.  SO AT THIS POINT
JUST EXPECT MOSTLY CLOUDY AND MILD CONDITIONS WITH OCCASIONAL WET
PERIODS.  CERNIGLIA

&&

.HYDROLOGY...INCONSEQUENTIAL LIGHT RAIN WILL COME TO AN END EARLY
TODAY WITH LITTLE AFFECT ON AREA RIVERS.  A SERIES OF WEATHER
SYSTEMS WILL MOVE ACROSS THE REGION FRIDAY INTO THE MIDDLE OF NEXT
WEEK.  AT THIS POINT NONE OF THESE SYSTEMS LOOKS THEY WOULD PRODUCE
HEAVY RAINS AND THE DRY PERIODS BETWEEN EACH SYSTEM WILL ALLOW A
REST PERIOD FOR THE RIVERS.

THEREFORE...THE POTENTIAL FOR FLOODING LOOKS VERY LOW WELL INTO NEXT
WEEK.  THERE ARE NO FLOODING CONCERNS FOR THE GREEN RIVER AT THIS
TIME.  CERNIGLIA

&&

.AVIATION...A WEAK UPPER LEVEL RIDGE OVER WA TODAY WILL SHIFT EWD ON
THU. FRONTAL REMNANTS WILL MOVE UNDER THE RIDGE TODAY WITH LOW LEVEL
ELY FLOW. MOISTURE IN THE LOWER AND MID LEVELS WILL DECREASE BY
MIDDAY...FIRST FROM AROUND SEATTLE NWD. HIGH LEVEL MOISTURE WILL
PERSIST THROUGH THE AFTERNOON. THE ATMOSPHERE WILL REMAIN STABLE
WITH LIGHT SE FLOW ALOFT.

NE OUTFLOW WINDS ACROSS THE N INTERIOR INCLUDING KBLI...IN THE 20
KNOTS GUSTING TO 30 KNOTS RANGE...WILL EASE BY MIDDAY.

KSEA...CEILINGS ARE ALREADY IMPROVING TO THE 5000 TO 6000 FT RANGE.
THE TAF WAS UPDATED TO REFLECT THIS. THE LOWER/MID LEVEL DECK SHOULD
SCATTER THIS AFTERNOON WITH MAINLY HIGHER LEVEL CLOUDS. NORTH WINDS
8 TO 11 KNOTS BECOMING EAST NORTHEAST 4 TO 8 KNOTS THIS AFTERNOON.
DTM

&&

.MARINE...ELY OFFSHORE GRADIENTS WILL CONTINUE OVER THE WATERS
THROUGH TONIGHT. THIS WILL EASE THE OUTFLOW WINDS OVER THE NORTHERN
INLAND WATERS. GALES MAY PERSIST A LITTLE LONGER THAN EXPECTED AT
THE E ENTRANCE SO I EXTENDED THAT INTO THE AFTERNOON...WITH ELY
SMALL CRAFT WINDS THEREAFTER. MOST THE WATERS WILL SEE LOW END SMALL
CRAFT WINDS TONIGHT...EXCEPT FOR PUGET SOUND AND THE N INTERIOR. DTM

&&

WA...WIND ADVISORY FOR WESTERN WHATCOM COUNTY UNTIL 10 AM.

PZ...GALE WARNING WEST ENTRANCE TO THE STRAIT AND CAMANO ISLAND TO
     POINT ROBERTS.
     SMALL CRAFT ADVISORY COAST...CENTRAL AND EASTERN
     STRAIT...ADMIRALTY INLET AND PUGET SOUND AND HOOD CANAL.

WEATHER.GOV/SEATTLE