Wind Advisory 3, NWS Seattle, WA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
905 PM PST SAT JAN 6 2007

.SYNOPSIS...A STRONG FRONTAL SYSTEM WILL MOVE THROUGH WESTERN
WASHINGTON SUNDAY. ANOTHER FRONT WILL REACH THE AREA TUESDAY. A COLD
UPPER LEVEL TROUGH AND SOME CANADIAN AIR WILL MOVE OVER THE AREA
WEDNESDAY.

&&

.SHORT TERM...A DEEP LOW REACHES THE B.C. COAST NORTH OF THE
CHARLOTTES AROUND DAYBREAK SUN. THE ASSOCIATED FRONTAL SYS WILL MOVE
THRU WRN WA...FOR A WINDY 20-30 MPH DAY WITH RAIN. THE TEMPS ALOFT
ARE JUST A LITTLE WARMER WITH THIS SYSTEM...SO A GOOD CHANCE THE
SNOW IN THE MOUNTAINS CHANGES OVER TO RAIN BELOW 4000 FEET FOR PART
OF THE DAY. THE MAIN INTERESTING FEATURE WITH THIS SYS ARE THE PRES
FALLS THE NAM PUTS IN THE LEE OF THE CASCADES FROM OMAK TO WENATCHEE
AND YAKIMA...PRESSURES FALLING THRU THE DAY AND THEN A SPECTACULAR
COLLAPSE BY SUNDAY EVENING. LOOKING UPSTREAM FOR PROBLEMS...THERE IS
ONLY A VERY MODEST SIMILAR EFFECT OFF THE OLYMPICS. THAT MAY
STRENGTHEN THE GRADIENT OVER THE SW INTERIOR AND INTO SRN PUGET
SOUND AND HOOD CANAL BY MIDDAY...SO WE MAY NEED A WIND ADVISORY FOR
THOSE AREAS. OFF THE NAM...THE SIX HOUR PRESSURE CHANGE ENDING AT
21Z SHOWS AN AREA OF 8MB FALLS ALONG THE EAST SLOPES OF THE CASCADES
AND VERY TIGHT GRADIENT DEVELOPING ALONG THE EAST SLOPES OF THE
CASCADES...AND STRONG RISES OVER THE B.C. COAST (+20MB OR MORE ALONG
THE COAST E OF THE CHARLOTTES) BUT ONLY +9MB MAX INTO THE STRAIT OF
JUAN DE FUCA. THAT IS ENUF FOR A FULL WLY GALE IN THE STRAIT. MM

.LONG TERM...LATEST 00Z GFS IS SIMILAR TO PREV RUNS DIGGING THE COLD
UPPER TROF THAT HAS BEEN OVER ALASKA THESE PAST DAYS SOUTHEAST TO
THE PACNW TUESDAY. FOR TUE NIGHT AND WED SCATTERED SHOWERS AND A LOW
SNOW LEVEL ARE A GOOD BET...AND THE MODIFIED ARCTIC FRONT MAY MOVE
THRU THE AREA AS WELL WED NITE. BY 12Z THU THERE IS A 1049MB HIGH
OVER B.C. AND ALTA SO COLD FRASER OUTFLOW IS LIKELY BY THAT TIME. MM

&&

.AVIATION...WARM FRONT MOVING INTO THE AREA TONIGHT WITH CEILINGS
RANGING FROM 2000 TO 3000 FEET ALONG THE COAST TO 6000 TO 8000 FEET
INLAND. CEILINGS WILL LOWER ALL AREAS TO 1000 TO 2000 FEET BY 12Z
WITH ISOLATED VISIBILITIES 3-5SM IN MODERATE RAIN. THESE CONDITIONS
WILL CONTINUE THROUGH THE MORNING HOURS.

FOR KSEA...8000 FOOT CEILING LOWERING TO NEAR 3000 FEET AFTER 09Z
WITH THE ONSET OF THE PRECIPITATION THEN DOWN TO NEAR 2000 FEET
13Z-16Z WITH INCREASING RAIN. COULD SEE VISIBILITIES LOWERING TO
3-5SM IN MODERATE RAIN AFTER 16Z. WINDS SOUTH 8 TO 12 KNOTS RISING
TO NEAR 15 KNOTS WITH GUSTS TO 25 KNOTS AFT 15Z. FELTON

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
.WINTER STORM WARNING CASCADES AND OLYMPICS LATE TONIGHT THROUGH
SUNDAY.
.FLOOD WATCH MASON COUNTY SUNDAY MORNING THROUGH SUNDAY
   NIGHT.
.GALE WARNING COAST AND STRAIT.
.SMALL CRAFT ADVISORY ADMIRALTY INLET...CAMANO ISLAND TO POINT
ROBERTS...PUGET SOUND AND HOOD CANAL.
.SMALL CRAFT ADVISORY FOR ROUGH CONDITIONS GRAYS HARBOR BAR.

WEATHER.GOV/SEATTLE