Blizzard and High Wind in Alaska, April 3 to 4, 2006

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM ADT MON APR 3 2006

.DISCUSSION...

THE WEATHER MAKER FOR THE NEXT 36 HOURS IS A DEVELOPING 985 MB LOW
OVER THE CENTRAL ALEUTIANS AT ABOUT 53N 171W (AS OF 08Z). A LOOK AT
THE UPPER LEVEL FORCING SHOWS A PROGRESSIVE LOW AMPLITUDE SHORT-WAVE
TROUGH OVER TOP OF THE LOW WITH AN ESTIMATED 135 KT 250 MB JET
HEADING FOR THE AKPENN. ANOTHER LOW SOUTH OF THE ALEUTIANS WILL
GRADUALLY DISSIPATE THIS MORNING AS THE LOW FURTHER EAST BECOMES
DOMINANT. THE NAM/GFS/UKMET ALL VERIFY WELL AND SHOW A SIMILAR
SOLUTION THROUGH THE SHORT-TERM FORECAST PERIOD.

A WARM FRONT EXTENDING FROM THE DEVELOPING LOW WILL TRACK NORTHWARD
ACROSS BRISTOL BAY AND WESTERN GULF TODAY AND THEN INLAND THIS
EVENING. RADAR AND SATELLITE ALREADY SHOW MOISTURE OVERSPREADING
THIS REGION. HOWEVER PRECIP IS NOT REACHING THE GROUND YET IN MOST
AREAS (00Z PAKN AND PANC SOUNDINGS SHOW A DRY LAYER NEAR THE
SURFACE). EXPECT STEADY PRECIP TO DEVELOP THROUGH THE MORNING HOURS
FROM BRISTOL BAY TO THE KENAI PENINSULA AND NORTH GULF COAST AND
THEN SPREAD INLAND THIS AFTERNOON. PRECIP TYPE WILL INITIALLY BE
SNOW IN MOST PLACES ALONG THE COAST BUT WILL SWITCH TO RAIN BY
AFTERNOON BEHIND THE WARM FRONT. EXPECT GALE FORCE WINDS IN THE
VICINITY OF THE LOW AND IN COLD ADVECTION AS THE LOW MOVES INTO
THE PACIFIC MONDAY NIGHT.

EAST-WEST PRESSURE GRADIENT ACROSS SOUTH-CENTRAL HAS BEEN STEADILY
INCREASING THE PAST FEW HOURS AND WILL CONTINUE TO INCREASE AHEAD OF
THE WARM FRONT. THIS WILL PRODUCE SOME STRONG WINDS THROUGH TURNAGAIN
ARM AND HIGHER ELEVATIONS. HOWEVER...MOIST SOUTHWEST FLOW WILL
PREVAIL FROM ABOUT 750 MB AND WILL COUNTER MUCH OF THE DOWNSLOPE AT
LOWER LEVELS RESULTING IN PRECIPITATION ACROSS THE ENTIRE AREA BY
LATE THIS AFTERNOON. THE SUSITNA VALLEY...PARTICULARLY ALONG THE
ALASKA RANGE...WILL PICK UP SOME SIGNIFICANT UPSLOPE SNOW DURING
THIS EVENT. CURRENT FORECAST OF SNOW ADVISORY THROUGH WEDNESDAY
WILL BE CONTINUED.

MODELS INDICATE ANOTHER LOW DEVELOPING SOUTH OF KODIAK ISLAND MONDAY
NIGHT IN RESPONSE TO A VORT-MAX MOVING AROUND THE BASE OF THE UPPER
TROUGH. THIS WILL SWING NORTHWARD ACROSS THE GULF TUESDAY AS THE
OLD LOW DROPS INTO THE PACIFIC. TOO EARLY TO PINPOINT THE POSITION
OF THIS LOW. IF IT MOVES FAR ENOUGH NORTH WE MAY BE LOOKING AT
ANOTHER ROUND OF SNOW FOR WESTERN KENAI/ANCHORAGE/MAT VALLEY TUESDAY
NIGHT INTO WEDNESDAY AS MODERATE TO STRONG COLD ADVECTION MOVES
THROUGH SOUTHWEST ALASKA INTO SOUTHCENTRAL. LOOK FOR MAINLY RAIN
ALONG THE COAST. AS PATTERN CONTINUES TO PROGRESS EASTWARD A NEW
SYSTEM MOVES TO THE WESTERN ALEUTIANS WEDNESDAY WHILE THE EASTERN
BERING AND SOUTHWEST ALASKA DRY OUT UNDER A SHORT-WAVE RIDGE.

LOOKING TO THE EXTENDED FORECAST PERIOD...GFS INDICATES A CONTINUED
PROGRESSIVE LOW AMPLITUDE WAVE PATTERN. THIS MEANS A GENERAL MOVEMENT
OF SYSTEMS FROM EAST TO WEST ACROSS THE VAST ALASKA DOMAIN WITH A
CHANCE OF PRECIP EVERY FEW DAYS. WITH NO STRONG TEMPERATURE ADVECTION
IN EITHER DIRECTION EXPECT TEMPERATURE RANGES TO HOLD FAIRLY
STEADY...MEANING THAT WINTER WILL CONTINUE TO HANG ON FOR AT
LEAST ANOTHER WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALES 120 130 155 165 170 171 172 179 180.
FIRE WEATHER...NONE.

SEB APR 06