Blizzard Watch 5, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
410 AM AKST WED JAN 14 2009

.ANALYSIS AND UPPER LEVELS...LARGE LOW COMPLEX CENTERED AROUND 50N
170W WILL REMAIN NEARLY STATIONARY FOR THE NEXT 24-36 HOURS WHILE
SENDING MULTIPLE WAVES ACROSS SW ALASKA. A STEADY STREAM OF
MOISTURE...ORIGINATING FROM THE TROPICS CONTINUES TO POUR OVER THE
STATE.

.MODEL DISCUSSION...MODELS ARE IN DECENT AGREEMENT FOR THE FIRST
COUPLE OF DAYS ON SYNOPTIC SCALE FEATURES. WE WILL SIDE WITH THE GFS
FOR SPECIFICS DUE TO BETTER CONSISTENCY. SEVERAL LOWS SPIN UP ALONG A
170 KT JET ON THE SOUTH SIDE OF THE MAIN LOW COMPLEX. THESE FEATURES
ROUND THE MAIN LOW AND END UP CROSSING THE ALASKA PENINSULA WITH
TIMING IS STILL THE BIGGEST QUESTION.

.SHORT TERM FORECAST...A FRONTAL BOUNDARY IS SITUATED FROM THE MAIN
LOW SOUTH OF THE CENTRAL ALEUTIANS THROUGH DUTCH HARBOR TO SOUTH OF
BETHEL. THIS FRONT WILL CONTINUE TO SHIFT NORTH AS THE NEXT LOW
APPROACHES THE AKPENN. THIS SECONDARY LOW CAN BE CLEARLY SEEN ON
SATELLITE THIS MORNING...CURRENTLY NEAR 38N 166W. PERIODS OF RAIN (OR
FREEZING RAIN IN THE LOWER VALLEYS) WILL CONTINUE TODAY AS THE FLOW
REMAINS OUT OF THE SOUTH. SUBTLE CHANGES IN WIND DIRECTION (FROM SE
TO S OR EVEN SW) WILL HAVE BIG IMPACT ON HOW MUCH PRECIP
FALLS...ESPECIALLY OVER SOUTHCENTRAL DUE TO DOWNSLOPING EFFECTS. THIS
NEXT LOW COMING UP THIS EVENING HAS A 130 KT JET STREAK ASSOCIATED
WITH IT WHICH WILL HELP ENHANCE AN ALREADY TIGHT GRADIENT OVER
SOUTHCENTRAL. THIS WILL LEAD TO WARNING LEVEL WINDS (WITH GUSTS UP TO
100 MPH) ALONG TURNAGAIN ARM AND HIGHER ELEVATIONS).

LET THE WARM UP COMMENCE! LOCATIONS THAT ARE YET TO RISE ABOVE
FREEZING WILL DO SO BY LATER TODAY. THE TROPICAL ORIGIN OF THE FLOW
IS BRINGING VERY WARM AIR NORTHWARD...MAKING PEOPLE FORGET ABOUT THE
COLD SNAP THAT HELD SUCH A TIGHT GRIP ON US FOR SO LONG.

BLIZZARD CONDITIONS WILL EXIST ON THE BACKSIDE OF THIS LOW FROM
NUNIVAK ISLAND TO THE PRIBILOFS THROUGH TONIGHT. STEADY SNOW WILL
CONTINUE ALONG THIS LINE...ESPECIALLY IN THE NORTHERN KUSKOKWIM
VALLEY. ELSEWHERE...MORE RAIN CAN BE EXPECTED ALONG WITH THE STRONG
GAP WINDS. THE SECOND STRONG LOW TAKES A VERY SIMILAR TO ITS
PREDECESSOR...APPROACHING THE AKPENN THURSDAY NIGHT. ANOTHER ROUND OF
VERY STRONG WINDS WILL AFFECT SOUTHCENTRAL THROUGH THE DAY FRIDAY AS
ANOTHER JET STREAK SCREAMS OVERHEAD.

.LONG TERM FORECAST...THE WARM, WINDY AND WET CONDITIONS PERSISTS
SOUTH AND EAST OF THE ALASKA RANGE. COOLER AIR FILTERS IN FROM THE
WEST AS A TROUGH DIGS ACROSS THE BERING SEA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 155 195.
         HIGH WIND WARNING 101 125 135.
MARINE...STORM WARNING 120.
         GALE WARNING 125 129 130 132 138 140 141 150 170 172 175 179
                      351 352 412 413 414.
         HEAVY FREEZING SPRAY WARNING 179 185 412.
FIRE WEATHER...NONE.

JCA