FXAK69 PAFG 281347
AFDAFG
NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
447 AM AKST SAT NOV 28 2009
.DISCUSSION...
THE REMNANTS OF THE LOW THAT WAS IN COOK INLET YESTERDAY MORNING
ARE NOW ACROSS THE NORTHWEST INTERIOR AND WILL RE-DEVELOP IN
THE SOUTHERN BEAUFORT SEA TODAY. THE LOW WILL THEN LIFT NORTH OF
BARROW SATURDAY. A 965 MB LOW PASSING A FEW HUNDRED MILES SOUTH
OF KODIAK ISLAND EARLY THIS MORNING WILL LIFT NORTHEAST TOWARD
YAKUTAT AND WEAKEN SATURDAY. THE NEXT LOW OF GREATER CONCERN IS A
982 MB LOW BETWEEN THE SOUTHERN TIP OF KAMCHATKA AND THE SOUTHERN
ALEUTIANS. THE MODELS ARE CONSISTENT IN DEEPENING THIS LOW TO
AROUND 960 MB AS IT PASSES JUST SOUTH OF THE PRIBILOF ISLANDS
MONDAY EVENING.
INTERIOR...FAIRLY QUIET WEATHER INTO MONDAY. SNOW IN PARTS OF THE
NORTHWEST INTERIOR WILL BE WINDING DOWN THIS MORNING AND SHOULD
TAPER TO FLURRIES THIS AFTERNOON AS THE LOW LIFTS NORTH INTO THE
BEAUFORT SEA. ADDITIONAL ACCUMULATIONS OF A COUPLE OF INCHES ARE
EXPECTED IN PARTS OF THE UPPER KOYUKUK VALLEY AND IN ZONE 218 FROM
THE PIPELINE WEST. THE LOW IN THE GULF MAY PRODUCE SOME SNOW
ACROSS PARTS OF THE EASTERN INTERIOR BY SATURDAY...AND THIS SYSTEM
MAYBE ABLE TO SQUEEZE OUT A COUPLE OF INCHES OF SNOW IN
SPOTS...WITH PERHAPS A BIT MORE IN THE EASTERN ALASKA RANGE. THE
UPSLOPE FLOW LOOKS TO BE FAIRLY WEAK AND SHORT LIVED WITH S'LY
FLOW ALOFT KICKING IN BY LATE IN THE WEEKEND. BEFORE THE S'LY FLOW
KICKS IN THERE MAYBE SOME AREAS OF LIGHT SNOW IN THE WESTERN AND
CENTRAL INTERIOR ON SUNDAY...WITH NOTHING MORE THAN AN INCH OF
SNOW.
ATTENTION WILL THEN TURN TO THE STRONG STORM SYSTEM IN THE SOUTHERN
BERING SEA THAT STILL LOOKS ON TRACK TO PRODUCE A STRONG CHINOOK
BY LATE MONDAY OR MONDAY NIGHT INTO TUESDAY. THE GFS AND NAM HAVE
50-60 KT WINDS AT 850 MB AND 70-80 KT AT 700 MB WITH A NEARLY 25
MB PRESSURE DIFFERENCE ACROSS THE RANGE. THIS SHOULD BE A GOOD SET
UP FOR WARNING CRITERIA WINDS IN THE PASSES...AND IT LOOKS LIKELY
THAT A HIGH WIND WATCH WILL NEED TO BE ISSUED LATER THIS WEEKEND.
THE ONSET OF THE HIGH WINDS IS STILL LATE IN DAY 3 SO WILL HOLD
OFF ON ANY WATCHES THIS MORNING.
WEST COAST...FAIRLY QUIET WEATHER ALSO EXPECTED ALONG THE WEST COAST
THIS WEEKEND. THE STORM SYSTEM THAT DEEPENS ACROSS THE SOUTHERN
BERING SEA WILL NOT BEGIN TO IMPACT THE WEST COAST UNTIL SUNDAY
NIGHT WITH INCREASING NORTHEAST WINDS ALONG THE Y-K DELTA COAST.
THE ONSET OF THE STRONG WIND LOOKS TO BE WELL AHEAD OF THE
SNOW...BUT THERE IS A GOOD CHANCE THAT BY MONDAY THERE WILL BE
BLIZZARD CONDITIONS ALONG THE Y-K DELTA COAST WITH SNOW SPREADING
NORTH ALONG A STRONG INVERTED SURFACE TROUGH MONDAY NIGHT AND
TUESDAY. THE EVENTUAL ORIENTATION OF THE SURFACE TROUGH WILL
DETERMINE WHERE THE STRONGEST WINDS ARE DURING THIS TIME. THERE
WILL VERY LIKELY NEED TO BE SOME ADDITIONAL WINTER STORM WATCHES AND
ADVISORIES DOWN THE ROAD FOR OTHER WEST COAST ZONES.
NORTH SLOPE...AN AREA OF SNOW WILL LIFT NORTH TO THE NORTHERN ARCTIC
COAST TODAY. THE BEST CHANCE OF SNOW WILL BE WEST OF NUIQSUT TO
BARROW WHERE A FEW INCHES OF SNOW SHOULD ACCUMULATE IN SPOTS. THE
SNOW SHOULD TAPER OFF TO FLURRIES TONIGHT AS THE LOW LIFTS WELL
NORTH OF THE COAST. PATCHY FOG AND FLURRIES CAN BE EXPECTED ALONG
THE REMAINDER OF THE ARCTIC COAST THIS WEEKEND. THE NEXT CHANCE OF
SNOW SHOULD HOLD OFF UNTIL TUESDAY IN ASSOCIATION WITH THE DEEP LOW
AND SURFACE TROUGH ALONG THE WEST COAST.
IN THE MID RANGE...HIGH ENERGY AMPLIFIED PATTERN ACROSS THE NORTH
PACIFIC AND WESTERN NORTH AMERICAN RESULTING IN...NOT
SURPRISINGLY...A LOT OF UNCERTAINTY IN THE FORECAST. 12Z NAEFS HAS A
LARGE SPREAD IN SOLUTIONS BY THU AM. ONE LIKELIHOOD SEEMS TO BE A
VERY COLD CORE LOW ANCHORED SOMEWHERE NEAR 72N/160E...BUT THIS WILL
ALLOW FOR A LOT OF DIFFERENT PATTERNS DOWNSTREAM.
ADDITIONALLY...EARLY IN THE MID RANGE MODELS AGREE ON A DECENT RIDGE
OVER BC/YT/WRN NWT WITH MODERATE TO STRONG SLY FLOW ALOFT EAST OF
160W. WE HAVE OPTED TO LEAN TOWARD HPC GUIDANCE THOUGH WITH SOME
MANUAL TWEAKING OF TEMPS.
AN ITEM OF INTEREST IS SUPER TYPHOON NIDA IN THE WESTERN PACIFIC
NEAR 20N 140E. THE MODELS HAVE SIGNIFICANT VARIATIONS FROM RUN TO
RUN WITH THE REMAINS OF THIS LOW LATE NEXT WEEK. THE STRONG
DOWNSTREAM RIDGE COULD SIGNAL A TURN TO THE NORTH...BUT IT'S ALSO
PLAUSIBLE THAT THE LOW UNDERCUTS THE RIDGE AND TAKES A TRACK WELL
SOUTH OF THE ALEUTIANS. GIVEN THAT IT IS CURRENTLY A SUPER TYPHOON
IT IS A SYSTEM THAT AT LEAST BEARS WATCHING OVER THE NEXT SEVERAL
DAYS.
COASTAL HAZARD POTENTIAL DAYS 3 AND 4...GALE FORCE NE WINDS MONDAY
WILL GRADUALLY BACK AROUND INTO THE NORTH BY TUESDAY. SEA ICE
ANALYSIS SHOWS A LOT OF SHOREFAST ICE FROM GAMBELL TO SAVOONGA
WITH 1 TO 3 TENTHS NEW ICE COVERAGE FURTHER OFFSHORE. WILL NEED TO
KEEP AN EYE ON THE SITUATION FOR POSSIBLE HIGH SURF ALONG THE
NORTH SHORE OF THE ISLAND.
&&
.AFG WATCHES/WARNINGS/ADVISORIES...
HEAVY FREEZING SPRAY WARNING FOR PKZ210.
&&
$$
CB/RT NOV 09
