Snow Advisory 1, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM AST TUE JAN 8 2008

.MODEL DISCUSSION...
MODELS CONTINUE TO BE IN GOOD AGREEMENT AND CONSISTENT WITH PREVIOUS
RUNS. ALL HANDLE THE LOWS IN THE GULF IN A SIMILAR MANNER THOUGH THE
GFS HAS MORE IN COMMON WITH THE UKMET AND THE EUROPEAN MODEL THAN THE
NAM.

.ANALYSIS AND UPPER LEVELS...
UPPER AIR...THE 500 MB TROUGH OVER WESTERN ALASKA CONTINUES TO DIG A
LITTLE FURTHER SOUTH INTO BRISTOL BAY AND IS BRACKETED BETWEEN AN
UPPER RIDGE OVER THE BERING SEA AND ANOTHER OVER THE BRITISH COLUMBIA
AND THE YUKON TERRITORY. THIS OMEGA BLOCK PATTERN IS NOT EXPECTED TO
MOVE OVER THE NEXT SEVERAL DAYS. A SOUTHERLY FLOW OVER THE GULF WILL
CONTINUE TO FEED MOISTURE INTO SOUTH CENTRAL ALASKA FOR THE NEXT FEW
DAYS.

AT THE SURFACE...
A LOW PRESSURE SYSTEM OVER THE GULF OF ALASKA WILL PROBABLY REMAIN IN
THE AREA AND SLOWLY WEAKEN THROUGH THURSDAY NIGHT. A SURFACE RIDGE
OVER THE BERING SEA WILL REMAIN IN PLACE THROUGH THURSDAY NIGHT AND
CONTINUE TO FEED COLD AIR OVER WESTERN ALASKA THROUGH THE PERIOD.

.SHORT TERM FORECAST...
SOUTH CENTRAL ALASKA AND THE GULF...
A 500 MB TROUGH OVER KODIAK ISLAND AND THE WESTERN GULF WILL MOVE
NORTHEAST THROUGH THE KENAI PENINSULA TONIGHT AND WEDNESDAY AND WILL
WEAKEN OVER THE SUSITNA VALLEY AND COPPER RIVER BASIN WEDNESDAY
NIGHT. A MODERATE SURFACE LOW OVER THE SOUTHEAST GULF WILL MOVE TO
JUST SOUTH OF THE KENAI PENINSULA WEDNESDAY AFTERNOON AND SLOWLY
WEAKEN THERE THROUGH THURSDAY NIGHT. THE BULK OF THE SNOW IS EXPECTED
WITH THE PASSAGE OF THE UPPER TROUGH TONIGHT AND WEDNESDAY AND THEN
WILL TAPER TO SHOWERS BEHIND IT. LOCAL GUSTY WINDS ALONG THE EAST
SIDE OF THE KENAI PENINSULA HAS CREATED BLIZZARD CONDITION NEAR
WHITTIER AND SEWARD. WINDS IN THESE AREAS WILL DIMINISH THIS EVENING
AND CONDITIONS WILL GENERALLY IMPROVE.

SOUTHWEST ALASKA...
THE UPPER TROUGH OVER WESTERN ALASKA IS EXPECTED TO REMAIN OVER THE
AREA THROUGH THURSDAY NIGHT. CLOUDS AND AREAS OF LIGHT SNOW WILL
PERSIST OVER THE AREA. NORTHERLY FLOW OVER THE LOWER ELEVATION WILL
CONTINUE TO FEED COLDER AIR OVER MOST OF THE REGION.

ALEUTIANS AND BERING SEA...
BOTH UPPER AND SURFACE RIDGE WILL PERSIST OVER THE CENTRAL BERING SEA
THROUGH NIGHT. WEATHER WILL REMAIN MOSTLY CLOUDY WITH SCATTERED
SHOWERS OVER THE CENTRAL AND EASTERN BERING THROUGH THURSDAY NIGHT.
NEW STORMS DEVELOPING OVER THE NORTHWEST PACIFIC WILL BRING GALE
FORCE WINDS INTO THE WESTERN ALEUTIANS THURSDAY AND THURSDAY NIGHT.

.LONG TERM FORECAST...
MID RANGE MODELS SHOW THE OMEGA BLOCK WILL HOLD THROUGH SATURDAY BUT
WILL BEGIN TO SPREAD EAST ON SUNDAY. THE SOUTHERLY FLOW OVER THE GULF
AND SOUTH CENTRAL ALASKA WILL CONTINUE FEEL MOISTURE INTO THE AREA.
CLOUDS AND PERIODS OF SNOW WILL CONTINUE THROUGH THE WEEKEND. COLDER
DRIER AIR WILL CONTINUE TO FLOW INTO SOUTHWEST ALASKA AND WILL PUSH
INTO SOUTH CENTRAL ALASKA SUNDAY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING FOR ZONE 125.
MARINE...NONE.
FIRE WEATHER...NONE.

NM JAN 08