Brisk Wind Advisory 141, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
103 PM AST SAT NOV 24 2007

.DISCUSSION...WARM AND ACTIVE WINTER PATTERN IN PLACE. TWO CLOSED
500MB FEATURES DRIVE THE BROAD-SCALE CIRCULATION: A BROAD BAG OF
LOW HEIGHTS OVER THE BERING SEA...AND A HIGH CENTERED JUST
NORTHWEST OF CANADAS BANKS ISLAND. EMBEDDED WITHIN THIS BROAD
PATTERN ARE NUMEROUS SHORT WAVE FEATURES. THESE SHORT WAVES WILL
PROGRESS BUSILY OVER THE NEXT COUPLE OF DAYS...BUT EXPECT NO
CHANGE IN THE LONG WAVE PATTERN SINCE THE LOW OVER THE BERING AND
THE HIGH NORTHWEST OF BANKS ISLAND ARE BOTH CUT-OFF FEATURES WHICH
TEND NOT TO MOVE RAPIDLY. AIRMASS IN PLACE IS QUITE MILD...NOT A
SINGLE SITE HAS REPORTED A LOW TEMPERATURE BELOW ZERO OVER THE
LAST 24 HOURS.

NORTH SLOPE...THERES A TIGHT SEA LEVEL PRESSURE GRADIENT ON THE
SOUTHWEST SIDE OF THE CLOSED HIGH PRESSURE SYSTEM...AND THIS IS
BRINGING THE HIGH WIND WARNING TO ZONE 204. OBSERVATIONS AND
NUMERICAL MODELS SUGGEST THAT THE STRONGEST WINDS ARE MAINLY OVER MARINE
AREAS 240 AND 245...ZONE 204 IS THE ONLY LAND AREA WITHIN THE REGION
OF STRONGEST WINDS. WIND GUSTS OVER 50 KT AT BARTER ISLAND ARE
UNUSUALLY STRONG FOR SUCH A WARM SYSTEM. INVERSIONS ON 12Z RAOBS
AT BARROW AND INUVIK ARE BETWEEN 900MB AND 950MB...PERHAPS THE
INVERSIONS PROVIDE A LID WHICH...WHEN COMBINED WITH THE HIGH
TERRAIN JUST INLAND OF ZONE 204...FUNNEL THE WIND AND PRODUCE AN
ACCELERATION IN ZONE 204 AND MARINE AREA 245. WE WILL EXTEND THE
HIGH WIND WARNING FOR ZONE 204 THROUGH THE NIGHT. AFTER A SHORT
WAVE FEATURE NOW ENHANCING THE GRADIENT PROGRESSES OUT OF THE
AREA...EXPECT WIND SPEEDS IN THE EASTERN ARCTIC TO DIMINISH
10-20 MPH SUNDAY. TEMPERATURES ARE SO WARM THAT WIND CHILL IS NOT
AN ISSUE DURING THIS EVENT. THERE ALSO APPEARS TO BE NO GOOD
MECHANISM TO PRODUCE NEW SNOWFALL...WHICH MEANS WE ARE LOOKING AT
A HIGH WIND EVENT RATHER THAN A BLIZZARD. WE NEED TO WATCH THIS
SITUATION CAREFULLY...BECAUSE IF ONE OF THESE SHORT WAVE FEATURES
SHOULD TURN OUT TO BE A SLIGHTLY STRONGER THAN WE EXPECT IT WONT
TAKE MUCH SNOWFALL TO DROP VISIBILITIES QUICKLY.

WEST COAST...MORE BOUTS OF LIGHT SNOW WITH TRANSITING SHORT WAVES
OVER THE NEXT FEW DAYS. THE MILD AIR TEMPERATURES MEANS THAT HEAVY
STRUCTURAL ICING IS NOT LIKELY OVER THE MARINE AREAS.

INTERIOR...DUE TO A TRANSITIONING SHORT WAVE...SOME LIGHT SNOW IN
THE NORTHERN INTERIOR TONIGHT ENDING FROM THE SOUTH...WITH SOME FOG
AND STRATUS DEVELOPING BEHIND THE SHORT WAVE. THEN THE TREND IS
FOR DRYING ON SUNDAY AND MONDAY AS COOLER AND DRIER AIR SLOWLY
DRIFTS IN FROM THE EAST. FREEZING RAIN IS ALSO POSSIBLE IN
ISOLATED SPOTS...BUT NO SIGNIFICANT ACCUMULATION.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY FOR AKZ219.

HIGH WIND WARNING FOR AKZ204.

SMALL CRAFT ADVISORY FOR PKZ200-PKZ210.

GALE WARNING FOR PKZ240.

STORM WARNING FOR PKZ245.

BRISK WIND ADVISORY FOR PKZ215-PKZ235.
&&

ES NOV 07