Gale Warning 298, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
200 PM AKDT TUE MAR 19 2013

.MODEL DISCUSSION...
THE GUIDANCE IS IN FAIRLY GOOD AGREEMENT WITH ONLY MINOR DIFFERENCES
IN THE FIRST 60 HOURS. SOME DIFFERENCES CROP UP AFTER 60 HOURS
MAINLY WITH THE LOCATION OF THE STORM TRACK (AND THUS SURFACE LOWS)
BUT ALL THE MODELS HAVE BASICALLY THE SAME IDEA. CONFIDENCE IS
HIGHER THAN AVERAGE FOR THIS TIME OF YEAR.

.ANALYSIS AND UPPER LEVELS...
AN UPPER LEVEL LOW IS OVER NORTHWEST CANADA AND MOVING WESTWARD.
THERE IS A NEGATIVELY TILTED RIDGE OF HIGH PRESSURE OVER THE BERING
SEA WHICH IS SLOWLY WEAKENING AS FLOW FROM A LOW FURTHER TO THE WEST
IS BEGINNING TO BREAK IT DOWN. FLOW ALOFT IS GENERALLY NORTHERLY
ACROSS SOUTHERN ALASKA AND THE EASTERN BERING SEA.

.SHORT TERM FORECAST...
THE FLOW ALOFT WILL GRADUALLY BECOME NORTHWESTERLY ON THROUGH
WEDNESDAY AS THE CANADIAN LOW WORKS WEST ACROSS NORTHERN ALASKA. ON
THURSDAY THE FLOW WILL BECOME WESTERLY AS THE STORM TRACK PUSHES
THROUGH THE BERING SEA...DESTROYING THE BERING SEA RIDGE IN THE
PROCESS. BY FRIDAY THE PATTERN WILL HAVE COMPLETED ITS CHANGE WITH A
LARGE UPPER LOW AND CYCLONIC FLOW ALOFT DOMINATING THE WEATHER
PICTURE.

FOR SOUTH CENTRAL ALASKA...STRONG GAP FLOW WINDS WILL CONTINUE
THROUGH WEDNESDAY AS THE FLOW ALOFT SWITCHES FROM NORTHERLY TO
NORTHWESTERLY. BY THURSDAY THE WINDS WILL HAVE MOSTLY DIED OFF. ON
THURSDAY NIGHT AND FRIDAY A WEATHER SYSTEM WILL HAVE WORKED ITS WAY
INTO SOUTH CENTRAL ALASKA AND SNOW IS EXPECTED FOR MOST AREAS. THE
PATTERN LOOKS FAVORABLE FOR A DECENT SNOWFALL EVENT...BUT IT IS A
LITTLE TO EARLY YET FOR DETAILS.

FOR SOUTHWEST ALASKA...A WEAK SYSTEM WILL MOVE INTO THE AREA FROM
THE NORTHWEST ON WEDNESDAY AND WEDNESDAY NIGHT FOR A CHANCE OF SNOW
THROUGH THE LOWER KUSKOKWIM VALLEY AND DELTA. ON THURSDAY AFTERNOON
A WEATHER SYSTEM IN THE WESTERLY FLOW WILL REACH THE KUSKOKWIM
DELTA...THEN SPREAD ACROSS THE ENTIRE AREA THURSDAY NIGHT.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE WARNING 127 128 130 132 138 150.
         HEAVY FREEZING SPRAY 121 126 127 128 129 130 138 140 141
                                150 160 165.
FIRE WEATHER...NONE.

LUDWIG MAR 13