Small Craft Advisory 15, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
430 AM AST THU JAN 4 2007

.DISCUSSION...

..SUMMARY..
TWO MAIN CONCERNS FOR THIS FORECAST PACKAGE INCLUDE SNOW OVER
SOUTHCENTRAL...AND A STRONG LOW PRESSURE OVER THE CENTRAL AND
WESTERN ALEUTIANS. SNOW IS TAPERING OFF ACROSS SOUTHCENTRAL THIS
MORNING. HOWEVER LIGHT SNOW IS EXPECTED TO REMAIN THROUGH THE MORNING
UNTIL THE UPPER LEVEL TROUGH PUSHES THROUGH. THE STRONG LOW PRESSURE
OVER THE CENTRAL AND WESTERN ALEUTIANS IS BRINGING STORM FORCE WINDS
WITH RAIN MIXED WITH SNOW ALONG AND AHEAD OF THE LOW...AND SNOW AND
BLIZZARD CONDITIONS ON THE BACK SIDE OF  THE LOW. THIS STORM WILL BE
A CONCERN AS IT MOVES FROM WEST TO EAST ALONG THE ALEUTIANS THROUGH
TONIGHT. A TRIPLE POINT LOW IS EXPECTED TO FORM THIS MORNING OFF THE
EAST WEST ORIENTED FRONT EXTENDING EAST FROM THE ABOVE MENTIONED LOW.
THIS LOW WILL TRACK INTO THE EASTERN GULF OF ALASKA BY TONIGHT AND
MOVE INLAND OVER THE NORTHERN PANHANDLE...TAKING A TRACK SLIGHTLY
FURTHER SOUTH THAN PREVIOUS LOW PRESSURES...MEANING PRECIPITATION IS
NOT EXPECTED TO MAKE IT TOO FAR INLAND WITH THIS SYSTEM. VERY COLD
TEMPERATURES AND GENERALLY DRY CONDITIONS TO DOMINATE THE INTERIOR
THROUGH THE WEEKEND.

..MODELS..
IN THE EAST...MODELS ARE IN DECENT AGREEMENT...BUT HAVE A SLIGHT
PREFERANCE OF GFS OVER NAM/WRF. IN THE WEST...GFS AND UKMET BOTH
INITIALIZED WELL. FAVORING THE GFS FOR THE NEXT SYSTEM SINCE IT
SPLITS THE ENERGY SOUTH OF THE CENTRAL ALEUTIANS. BELIEVE THIS TO BE
THE MORE REASONABLE SOLUTION BY FRI.

..FORECAST EAST AND SOUTH OF THE ALASKA RANGE..
EXPECT SNOW TO END EARLY THIS AFTERNOON AS THE 700 AND 500 MB TROUGHS
FINALLY PUSH THROUGH THE REGION. OTHERWISE VERY LIGHT SNOW WILL
CONTINUE THIS MORNING. LOOK FOR FOG TO DEVELOP TONIGHT ACROSS THE
AREA WITH SOME RADITIONAL COOLING. SUBSEQUENT AREAS OF LOW PRESSURE
EXPECTED TO TRACK A BIT FURTHER SOUTH...MEANING A DRIER AND COLDER
WEATHER PATTERN SETTING UP FOR INLAND AREAS. SOME OF THE UPCOMING LOW
PRESSURES COULD BRUSH AREAS AS FAR NORTH AS PALMER AND
ANCHORAGE...BUT GENERALLY SPEAKING...A BREAK FROM THE MAJOR
SNOWSTORMS IS IN STORE. COASTAL AREAS OF SOUTHCENTRAL WILL STILL GET
BRUSHED BY THE LOWS OVER THE GULF OF ALASKA THROUGH THE
WEEKEND...THOUGH NOTHING MAJOR IS EXPECTED. GUSTY OFFSHORE WINDS
THROUGH GAPS IN THE TERRAIN CAN BE EXPECTED IN THIS PATTERN.

..FORECAST FOR THE SOUTHWEST MAINLAND..
GENERALLY VERY QUIET AND VERY COLD WEATHER TO PERSIST FOR THE
SOUTHWEST MAINLAND THROUGH THE WEEKEND WITH ARCTIC HIGH PRESSURE
OVER THE AREA. SOME SNOW FALLING AROUND MCGRATH TODAY ON THE FAR
WEST SIDE OF THE PLUME OF MOISTURE FROM THE DISSIPATING LOW OVER
SOUTHCENTRAL...BUT THIS SNOW SHOULD DISSIPATE BY THIS AFTERNOON. SOME

AREAS WILL SEE TEMPERATURES AROUND 45 BELOW OVER THE NEXT FEW DAYS.
EXPECT SOME LOW STRATUS AND PATCHY FOG ALONG THE COAST IN THE
MORNINGS.

...FORECAST FOR THE BERING/ALEUTIANS...
A STRONG LOW IS BRINGING STORM FORCE WINDS AND BLOWING SNOW WITH
LOCALIZED BLIZZARD CONDITIONS MAINLY ON ITS BACK SIDE. SIGNIFICANT
SNOW OR SNOW CHANGING TO RAIN IS PRESENT ALONG A FRONT EXTENDING TO
THE EAST OF THE LOW ALONG THE CHAIN. THE LOW AND ASSOCIATED FRONT
WILL MOVE EAST THROUGH THE ALEUTIANS...EXITING THE AREA ON FRIDAY.
ONLY WEAK SYSTEMS WILL BE PRESENT OVER THE REGION FOR THE WEEKEND.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 187
         BLIZZARD WATCH 181 185
MARINE...GALE 150 155 170 171 172
         HEAVY FREEZING SPRAY 120 121 130 132 138 140 141 150 160
                              165 179 185

RNW JAN 07