Gale Warning 1042, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AST SAT DEC 23 2006

.DISCUSSION...

...SUMMARY...
MAIN CONCERN IS A STRONG LOW PRESSURE IN THE NORTHERN GULF THIS
MORNING MOVING ONSHORE SOUTHCENTRAL ALASKA TODAY...BRINGING ABUNDANT
SNOW AND WIND TODAY AND TONIGHT. THIS WILL BE THE LAST BIG STORM FOR
SOUTHCENTRAL FOR A WHILE...AS THE STORM TRACK APPEARS TO SHIFT MORE
TOWARD THE PANHANDLE. IN THE BERING AND ALEUTIANS...THERE ARE NO BIG
SYSTEMS...BUT THERE ARE PLENTY OF SNOW SHOWERS IN NORTHWEST FLOW.
THIS WILL CONTINUE INTO NEXT WEEK.

...MODELS...
MODELS INITIALIZED DECENT WITH THE LOW NEAR MIDDLETON ISLAND THIS
MORNING. HOWEVER...NAM/WRF STILL BRINGS THE LOW INTO FAR WESTERN
PRINCE WILLIAM SOUND...WHILE GFS HAS THE LOW DISSIPATING OVER THE
SOUTHERN TIP OF THE KENAI PENINSULA. NAM/WRF LOW POSITION WOULD MEAN
MORE SNOW FOR ANCHORAGE. NOT TOTALLY SURE WHICH MODEL TO TRUST...BUT
WILL SIDE WITH NAM/WRF SINCE IT BETTER REFLECTS THE PREVIOUS
FORECAST...AND BECAUSE NAM/WRF INITIALIZED SLIGHTLY BETTER WITH THE
POSITION OF THE LOW. QUITE A BIT OF DISAGREEMENT ON THE NEXT GULF
LOW SUNDAY INTO MONDAY...WITH THE GFS FURTHEST WEST...NAM/WRF
FURTHEST EAST...AND OTHER MODELS IN BETWEEN. A COMPROMISE LOOKS BEST
FOR NOW...BUT EITHER WAY...THIS LOW WILL LIKELY REMAIN EAST OF MOST
OF THE FORECAST AREA FOR NORTHERLY WINDS OVER OUR AREA ON THE WEST
SIDE OF THE LOW. IN THE BERING AND ALEUTIANS...MODELS ARE STRUGGLING
AND WILL CONTINUE TO STRUGGLE WITH THE SMALL LOW PRESSURES...BUT
CONFIDENCE IS HIGH ON COLD...SHOWERY PATTERN TO PERSIST INTO THE
MIDDLE OF NEXT WEEK WITH THE JET SOUTH OF THE AREA.

...SOUTHCENTRAL FORECAST SOUTH AND EAST OF THE ALASKA RANGE...
THE PRINCE WILLIAM SOUND AREA WILL DEFINITELY CONTINUE TO GET
SNOW...TRANSITIONING TO SNOW SHOWERS LATER TODAY. SNOW HAS NOT YET
MADE IT TO VALDEZ...BUT THIS WILL CHANGE LATER TODAY. LESS FORECAST
CONFIDENCE...HOWEVER...ON SNOWFALL FROM KENAI TO ANCHORAGE TO
PALMER...AS THESE AREAS LIE ON THE NORTHWEST EDGE OF THE STORM.
POTENTIAL IS CERTAINLY THERE FOR A BIG SNOW FOR ANCHORAGE...BUT
THERE ARE SOME CONCERNS. MAIN CONCERN IS THE DRY LOWER ATMOSPHERE AS
INDICATED ON THE 3AM SOUNDING THIS MORNING. SNOW HAS HAD TROUBLE SO
FAR MAKING IT TO THE GROUND DESPITE SNOW FALLING ALOFT. DO BELIEVE
THAT ANCHORAGE WILL RECOVER FROM THIS EVENTUALLY...THOUGH IT MAY
MEAN A LATER START TO THE ACCUMULATING SNOW. ANOTHER CONCERN IS
EXACTLY WHERE THE SHARP WEST EDGE OF THE SNOW SETS UP. RIGHT NOW THE
WEST EDGE APPEARS TO SET UP JUST WEST OF ANCHORAGE NEAR FIRE
ISLAND...BUT ANY SMALL CHANGE IN THIS WILL MEAN BIG CHANGES TO THE
WEATHER. ALSO...CONCERNED ABOUT LACK OF STRONG FLOW UP COOK INLET
LATER TODAY LIMITING THE ANCHORAGE SNOW ENHANCEMENT THAT OFTEN
OCCURS WITH UP INLET FLOW. IT WILL BE VERY INTERESTING TO SEE WHAT
HAPPENS TODAY INTO TONIGHT.

SNOW MOSTLY TAPERS OFF SUNDAY EXCEPT FOR PRINCE WILLIAM
SOUND...WHERE THE SNOW SHOULD KEEP GOING UNTIL SUNDAY NIGHT. FLOW
TRANSITIONS INTO STRONG OFFSHORE FLOW FOR MONDAY WITH DRIER BUT COLD
WEATHER IN STORE AS THE UPCOMING LOW PRESSURE SYSTEMS APPEAR TO HEAD
MORE TOWARD THE PANHANDLE. VERY LITTLE CONFIDENCE PAST
MONDAY...HOWEVER...ON WHETHER THE GULF LOWS HEAD UP TOWARD
SOUTHCENTRAL OR TOWARD THE PANHANDLE.

...SOUTHWEST MAINLAND FORECAST...
GENERALLY VERY QUIET WEATHER IN STORE FOR THE SOUTHWEST MAINLAND
THROUGH NEXT WEEK WITH HIGH PRESSURE IN PLACE ALONG WITH VERY COLD
TEMPERATURES. THERE MAY BE SOME LIGHT SNOW AT TIMES OVER THE NEXT
FEW DAYS AROUND THE KUSKOKWIM DELTA...BUT NOTHING MAJOR. ONE SNOW
BAND NEAR BETHEL TODAY DOES BEAR WATCHING...HOWEVER. VERY LITTLE LOW
CLOUDS AND FOG AROUND THE SOUTHWEST MAINLAND NOW...BUT IT WILL BE A
FORECAST CHALLENGE TO FIGURE OUT HOW LONG THE AREA CAN STAY FOG FREE
WITH HIGH PRESSURE AND LIGHT WINDS.

...BERING SEA/ALEUTIAN FORECAST...
A WEAK NEAR STATIONARY LOW NEAR DUTCH HARBOR BROUGHT SOME SNOW TO
THEM LAST NIGHT...AND WILL BE THE MAIN FORECAST CHALLENGE FOR TODAY
INTO TONIGHT FOR THE REGION. THIS LOW SHOULD BRING MORE SNOW TO
DUTCH TODAY...AND POSSIBLY TO COLD BAY TONIGHT. FROM THE PRIBILOFS
AND DUTCH HARBOR WEST...UNSTABLE NORTHWEST FLOW PERSISTS WITH SNOW
SHOWERS. LITTLE CHANGE IS EXPECTED IN THIS PATTERN THROUGH THE
MIDDLE OF NEXT WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 125.
MARINE...STORM WARNING 350.
         GALE WARNINGS 120 121 130 132.
         HEAVY FREEZING SPRAY WARNINGS 121 129 185.

FOISY DEC 06