Blizzard Watch 25, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
130 PM ADT TUE APR 1 2008

.ANALYSIS AND UPPER LEVELS...
VERY PROGRESSIVE...ACTIVE WEATHER PATTERN PRESENT OVER THE STATE
WITH STRONG WEST TO EAST FLOW. THIS AFTERNOON AT UPPER LEVELS...A
TROUGH IS PRESENT WEST OF THE ALEUTIAN CHAIN...A RIDGE OVER THE
CENTRAL BERING...A TROUGH OVER THE SOUTHWEST MAINLAND...AND A
BLOCKING RIDGE OVER THE YUKON. THINGS GET A BIT MORE COMPLICATED AT
THE SURFACE...WITH TWO SURFACE TROUGH AXES ASSOCIATED WITH THE UPPER
LEVEL TROUGH. ONE TROUGH AXIS IS ORIENTED NORTHWEST TO SOUTHEAST
OVER KODIAK ISLAND...WITH AN EMBEDDED SURFACE LOW NEAR OR JUST WEST
OF BUOY 46001. THE STRONGEST WINDS AND MAJORITY OF PRECIPITATION ARE
AHEAD OF THIS TROUGH AXIS. THE OTHER TROUGH AXIS IS ORIENTED NORTH
SOUTH OVER THE FAR EASTERN BERING...WITH THE STRONGEST WINDS AND
MAJORITY OF PRECIPITATION ON THE BACK SIDE OF THIS TROUGH AXIS. A
STRONG OCCLUDED FRONT IS APPROACHING THE WESTERN ALEUTIANS.

.MODEL DISCUSSION...
MODELS ARE IN FAIR AGREEMENT WITH FORECAST FAVORING GFS WHERE
DISCREPANCIES ARISE.

.SHORT TERM FORECAST...
SOUTHCENTRAL...
SURFACE LOW PRESSURE IN THE GULF OF ALASKA WILL SLOWLY MOVE NORTH TO
NEAR SEWARD THROUGH WEDNESDAY AND THEN DISSIPATE. HOWEVER...MOIST
AND MILD UPPER LEVEL SOUTH TO SOUTHWEST FLOW WILL PERSIST THROUGH
FRIDAY. COASTAL AREAS WILL SEE PERSISTENT RAIN MIXED WITH SNOW AT
TIMES. THE CHALLENGE WILL BE DECIDING WHEN AND IF ANY PRECIPITATION
REACHES THE NORMALLY DRIER AREAS FROM KENAI NORTHEAST TO THE
ANCHORAGE BOWL AND MATSU VALLEY. WITH UPPER LEVEL SOUTH TO SOUTHWEST
FLOW...IT IS POSSIBLE THAT SOME MEASURABLE PRECIPITATION WILL
FINALLY REACH THESE AREAS...THOUGH IF IT DOES...TEMPERATURES SHOULD
BE TOO WARM FROM ACCUMULATING SNOW.

SOUTHWEST MAINLAND...
UNSETTLED WEATHER TO PERSIST OVER THE SOUTHWEST MAINLAND WITH
PERIODS OF RAIN AND SNOW AS LOW PRESSURE SYSTEMS MOVE SOUTHWEST TO
NORTHEAST ACROSS THE BERING...PASSING JUST NORTH OF THE SOUTHWEST
MAINLAND. MAIN CONCERN COMES TOMORROW NIGHT WITH A STRONG WARM FRONT
MOVING ONSHORE. BLIZZARD CONDITIONS ARE POSSIBLE AHEAD OF THE FRONT
FROM THE WESTERN CAPES TO THE KUSKOKWIM DELTA COAST.

BERING SEA/ALEUTIANS...
SNOW SHOWERS AND GUSTY WINDS ARE PRESENT OVER THE EASTERN
BERING/ALEUTIANS/AKPEN THIS AFTERNOON...BUT THESE WILL BE SHORTLIVED
AS A FAST MOVING SHORTWAVE RIDGE MOVES IN LATER TONIGHT. A FAIRLY
STRONG LOW AND ASSOCIATED FRONT WILL MOVE INTO THE WESTERN ALEUTIANS
TONIGHT AND THROUGH THE CENTRAL BERING WEDNESDAY AND WEDNESDAY NIGHT.
A WEAKER LOW FOLLOWS A SIMILAR TRACK THURSDAY THROUGH FRIDAY.

.LONG TERM FORECAST...
PATTERN CHANGE APPEARS TO TAKE PLACE BEGINNING THIS WEEKEND...WITH
THE MEAN CYCLONIC FLOW MOVING EAST FROM THE EASTERN BERING INTO THE
MAINLAND...BRINGING WITH IT COLDER TEMPERATURES TO THE MAINLAND.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WATCH ZONES 155 161 195.
MARINE...GALE WARNING ZONES 120 125 165 170 171 172 175 176 179.
FIRE WEATHER...NONE.

FOISY APR 08