Brisk Wind Advisory 17, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
559 AM AKST SUN JAN 9 2011

.DISCUSSION...
THE GFS AND NAM COMPUTER WEATHER FORECAST MODELS HAVE SIMILAR
PROJECTIONS THROUGH MONDAY NIGHT. THE STRONG LOW THAT CROSSED THE
ALEUTIANS FRIDAY EVENING IS NOW WEAKENING AND HEADED RAPIDLY INTO
THE CHUKCHI SEA. THIS WEATHER SYSTEM HAS BEEN AN UNUSUAL ONE IN
TERMS OF ITS FAST MOVEMENT AND IN THE AMOUNT OF FREEZING RAIN IT
HAS BROUGHT TO THE WEST AND NORTHWEST REGIONS OF NORTHERN ALASKA.

WHILE THIS SEQUENCE OF WEATHER EVENTS OVER NORTHERN ALASKA HAS
INDEED BEEN UNUSUAL...THE COMPUTER WEATHER FORECASTS FOR NORTHERN
ALASKA DURING THE PAST 2 DAYS HAVE BEEN CONSISTENT AND ACCURATE.
THIS HAS BEEN TRUE FOR THE SHORTER RANGE PREDICATIONS / OUT TO 60
HOURS / AS WELL AS THE FORECASTS FOR 3 TO 7 DAYS INTO THE FUTURE.

FOLLOWING THE STRONG LOW FROM THE BERING SEA / LOW NUMBER 1 / IS
ANOTHER LOW / LOW NUMBER 2 / JUST ABOUT 24 HOURS BEHIND ITS
PREDECESSOR. THE COMPUTER MODELS HAVE BEEN CONSISTENT IN
FORECASTING LOW NUMBER 2 TO MOVE NORTHWESTWARD...AND TO ARRIVE ON
THE NORTHERN KAMCHATKA PENINSULA EARLY MONDAY.

AS IN SIMILAR PAST CASES...LOW NUMBER 1 ACQUIRED A GOOD PORTION OF
ITS ENERGY VIA A STRONG INFLOW OF SUBTROPICAL AIR FROM ABOUT 25
DEGREES NORTH LATITUDE UP TO THE ALEUTIANS AND THE EAST BERING
SEA. THIS INFLUX OF ENERGY IS NOW DIMINISHING.

THE ENERGY THAT ACCOMPANIED LOW NUMBER 1 IS NOW HEADED NORTH WITH
THE LOW. THE STRONG WINDS AND WINTER WEATHER THAT CAME WITH THE
LOW ARE RAPIDLY DIMINISHING FROM THE SOUTH AND THE REMAINS OF THE
STORMY WEATHER ARE HEADED NORTHEASTWARD OVER THE ARCTIC SLOPE
ZONES.

THE STRONG HIGH PRESSURE SYSTEM ALOFT NOW BUILDING OVER SOUTHWEST
ALASKA IS CONTINUING TO BUILD AND IS EXPECTED TO BE CENTERED NEAR
KOTZEBUE EARLY MONDAY. FROM THERE...THE HIGH IS FORECAST TO BUILD
WESTWARD OVER THE CHUKCHI SEA FOR THE REMAINDER OF THIS WEEK.

THIS PATTERN OF CIRCULATION BROUGHT IN A LARGE MASS OF WARM AIR
ALOFT...UP OVER THE ALEUTIANS TO NEARLY ALL OF NORTHERN ALASKA. AS
THE HIGH ALOFT NOW OVER SOUTHWEST ALASKA EXITS WESTWARD...THE
WARMING WILL END. STARTING MONDAY AFTERNOON...COLDER AIR WILL
ADVANCE OVER NORTHERN ALASKA FROM THE MACKENZIE RIVER REGION OF
CANADA. THIS INFLUX WILL NOT BE STRONG ENOUGH TO BRING IN SEVERE
COLD...BUT THERE SHOULD BE LARGE AREAS OF 20 TO 30 BELOW
TEMPERATURES IN EASTERN INTERIOR VALLEYS. THE LARGE INTERIOR
TEMPERATURE INVERSIONS / 20 TO 30 DEGREES FAHRENHEIT BETWEEN
VALLEYS AND HIGHLANDS / WILL WEAKEN A LITTLE AS THE COLDER AIR
ADVANCES.

THIS MORNINGS POLAR ORBITING SATELLITE IMAGERY SHOWS THE LARGE
OVERCAST DECK OF STRATOCUMULUS THAT WAS OVER THE EASTERN INTERIOR
YESTERDAY NOW COVERING NEARLY ALL OF THE YUKON TERRITORY.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

WINTER WEATHER ADVISORY FOR AKZ201-AKZ202-AKZ203-AKZ205.

GALE WARNING FOR PKZ220-PKZ225.

BRISK WIND ADVISORY FOR PKZ200-PKZ210-PKZ215-PKZ230-PKZ235-
PKZ240.
&&

TF JAN 11