Brisk Wind Advisory 6, NWS Fairbanks, AK

NORTH ALASKA FORECAST DISCUSSION
230 PM AST TUE JAN 4 2005

.DISCUSSION...A VERY ACTIVE WEATHER PATTERN CONTINUES OVER
NORTHERN ALASKA. W-LY TO SW-LY FLOW ALOFT IS MOVING A SERIES OF
SHORTWAVES OVER THE STATE AS THE STRONG RIDGE OF HIGH PRESSURE
THAT HAD EXTENDED N-WARD OVER EASTERN MAINLAND ALASKA IS
TEMPORARILY FLATTENED TO THE SOUTH. THE COMBINATION OF AMPLE
MOISTURE AND BROAD W-LY FLOW HAS BROUGHT A GOOD SNOWFALL TO MANY
AREAS OF INTERIOR ALASKA OVER THE LAST COUPLE OF DAYS. SNOWFALL
AMOUNTS OF UP TO 12 INCHES HAVE BEEN OBSERVED ACROSS THE CENTRAL
INTERIOR WITH LESSER AMOUNTS BEING REPORTED ACROSS THE EASTERN
INTERIOR.

DEEP LOW PRESSURE OVER THE HIGH ARCTIC IS GENERATING STRONG W-LY
WINDS AND AREAS OF BLOWING SNOW ALONG THE ARCTIC COAST. PARTLY TO
MOSTLY CLOUDY SKIES ARE BEING OBSERVED OVER THE WEST COAST AHEAD
OF THE NEXT SHORTWAVE THAT WILL BRING MORE SNOW TO THE REGION
TONIGHT AND WED. THIS NEW SHORTWAVE WILL THEN BRING ANOTHER ROUND
OF ACCUMULATING SNOW TO THE CENTRAL AND EASTERN INTERIOR ON WED
AND WED NIGHT AFTER A BIT OF A BREAK IN THE SNOWFALL TONIGHT. THE
STRONG WINDS ALONG THE ARCTIC COAST ARE EXPECTED TO CONTINUE
THROUGH WED BEFORE DIMINISHING WED NIGHT AS THE LOW CENTER TO THE
NORTH MOVES OFF TO THE EAST. TEMPS REMAIN WELL ABOVE NORMAL OVER
ALL OF MAINLAND ALASKA WITH +20F OR HIGHER TEMPS BEING REPORTED AT
MANY LOCATIONS.

MODEL OUTPUT THEN IS IN GOOD AGREEMENT IN FORECASTING A PATTERN
CHANGE BEGINNING ON WED NIGHT AND CONTINUING INTO THE WEEKEND. A
STRONG WARM FRONT IS EXPECTED E-WARD AND N-WARD OVER THE STATE ON
WED NIGHT AND THURS. AHEAD OF THE WARM FRONT, YET ANOTHER AREA OF
SNOW IS EXPECTED TO MOVE E-WARD ACROSS THE STATE WITH A LEAST A
FEW INCHES OF SNOW LIKELY TO FALL ACROSS THE INTERIOR. BEHIND THIS
WARM FRONT, VERY STRONG HIGH PRESSURE RIDGING IS EXPECTED TO BUILD
SLOWLY N-WARD ACROSS THE STATE THU THROUGH SAT. 500 MB HEIGHTS ARE
FORECAST BY ALL THE MODELS TO RISE TO AS HIGH AS 586 DM OVER
SOUTHWEST ALASKA THU NIGHT AND FRI, THEN REMAIN NEAR THESE VALUES
INTO THE WEEKEND. THESE 500 MB HEIGHTS ARE JUST ABOUT AS HIGH AS
WE SAW DURING THE HOTTEST DAYS OF LAST SUMMER STRONG HIGH
PRESSURE AT THE SURFACE IS ALSO EXPECTED TO BUILD N-WARD OVER THE
STATE UNDERNEATH THE RIDGING ALOFT, ENDING THE SNOW AND BRINGING
OF CLEARING OF THE CLOUD COVER FROM WEST TO EAST ON THU NIGHT AND
FRI ACROSS THE SOUTHERN 2/3 OF MAINLAND ALASKA.

ONCE THE SKIES CLEAR, SOME VERY STRONG INVERSIONS SHOULD DEVELOP
IN THE VALLEYS OF THE INTERIOR WITH VERY WARM AIR ALOFT KEEPING
TEMPS OVER THE HILLTOPS QUITE WARM. ANOTHER ROUND OF STRONG W-LY
WINDS, CLOUDS, AND SNOW OVER THE ARCTIC ZONES IS BEING FORECAST BY
ALL THE MODELS ON THU NIGHT AND FRI AS ANOTHER LOW CENTER MOVES
E-WARD OVER THE HIGH ARCTIC. A COOLING TREND IS POSSIBLE FROM SUN
ONWARD INTO EARLY NEXT WEEK AS THE HIGH PRESSURE RIDGE IS
FLATTENED BACK TO THE SOUTH BY A STRONG COLD FRONT MOVING IN FROM
THE NORTHWEST.

.AFG WATCH/WARNING/ADVISORIES...
PUBLIC...WINTER WX ADVY 202...203...224 222...223...225 THIS
EVENING. WINTER STORM WARNING 205 THIS EVENING. WINTER STORM
WARNING 224...225...226 TONIGHT.
MARINE...BRSK 9A...10B...11A AND 11B. GALE AND HEAVY FREEZING
SPRAY WRNG 9B TONIGHT/WED.

MP JAN 05