Heavy Freezing Spray Warning 149, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
200 PM AKDT TUE MAR 27 2012

.ANALYSIS AND UPPER LEVELS...A RELATIVELY BENIGN PATTERN IS IN PLACE
OVER THE BERING SEA AND MAINLAND ALASKA TODAY CONSISTING OF A BROAD
UPPER TROUGH POSITIONED NEAR THE EASTERN BERING SEA. THE EASTERN
PORTION OF THE STATE IS UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE
EXTENDING OUT OF WESTERN CANADA. A FRONTAL BOUNDARY BETWEEN THESE TWO
LARGE SCALE FEATURES HAS STALLED NEAR KODIAK AND THE ALASKA
PENINSULA. A QUICK MOVING LOW CAUGHT IN THE JET STREAM WELL SOUTH OF
OUR DOMAIN IS RACING TO THE EAST AND WILL HAVE LITTLE TO NO IMPACT ON
OUR AREA OF RESPONSIBILITY UNTIL LATER IN THE WEEK. MULTIPLE
SHORTWAVES EMBEDDED IN THE SOUTHEASTERLY FLOW ALOFT ARE BRINGING
PERIODS OF RAIN AND SNOW TO THE NORTHWESTERN GULF AS WELL AS THE
SOUTHWESTERN MAINLAND.

.MODEL DISCUSSION...MODELS CONTINUE TO BE IN EXCELLENT AGREEMENT AND
CONSISTENT WITH PREVIOUS RUNS. ALL OF THE MODELS APPEAR TO NOT QUITE
MATCH UP WITH THE CENTER OF CIRCULATION NEAR THE PRIBILOF ISLANDS
WHEN COMPARED TO THE 18Z INFRARED SATELLITE. EVEN WITH THIS MINOR
INITIALIZATION ISSUE...DO NOT EXPECT MANY CHANGES TO THE AFTERNOON
FORECAST.

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...
THE FIRST OF MANY EASTERLY SHORT WAVES IS IMPACTING SOUTHCENTRAL
ALASKA TODAY. STEADY SNOW AND RAIN IS FALLING ALONG THE NORTHWEST
GULF COAST INCLUDING KODIAK ISLAND ASSOCIATED WITH THIS FIRST WAVE. A
SECOND WEAK WAVE WILL MAINTAIN THE ENHANCED PRECIPITATION ALONG THE
COAST AND CLOUD COVER OVER THE INTERIOR TONIGHT...THEN A MUCH
STRONGER WAVE WILL MOVER TOWARD THE SOUTHERN KENAI PENINSULA
WEDNESDAY MORNING. THE POTENTIAL FOR WARMER TEMPERATURES WILL
CONTINUE THROUGH MID TO LATE WEEK AS THE THICKNESS INCREASES WITH
EACH SUCCESSIVE EASTERLY WAVE. CLOUD COVER IS INTRODUCING A VARIABLE
THAT COULD LEAD TO TEMPERATURES NOT REACHING THE 40S AS ADVERTISED.
THE BEST CHANCE FOR CLOUDS TO SCATTER OUT WILL BE WEDNESDAY AND AGAIN
THURSDAY AFTERNOON CONGRUENT WITH SUBSIDENCE BEHIND THE SHORT WAVES.
IF THIS HAPPENS...EXPECT TEMPERATURES TO QUICKLY JUMP UP INTO THE
LOWER TO MID 40S AROUND SOUTHCENTRAL.

BY THURSDAY...THE AFOREMENTIONED LOW RACING SOUTH OF OUR DOMAIN WILL
STALL OVER THE NORTHEASTERN PACIFIC AND BEGIN TO FILL. AS IT
DOES...COLD AIR WILL VERY SLOWLY FILTER ACROSS THE STATE ALLOWING
TEMPERATURES TO RETURN TO NEAR OR SLIGHTLY BELOW NORMAL.

SOUTHWEST ALASKA AND ALEUTIANS...
THE STALLED FRONT AND EASTERLY WAVE HAS ENHANCED THE SNOW OVER
SOUTHWEST ALASKA MORE THAN ANY OTHER REGION. LIGHT SNOW IS FALLING
FROM BRISTOL BAY UP TO THE KUSKOKWIM VALLEY. A TIGHT PRESSURE
GRADIENT ACROSS THE REGION IS ALSO RESULTING IN BLUSTERY WINDS
ESPECIALLY NEAR BRISTOL BAY. THESE CONDITIONS WILL VERY SLOWLY
IMPROVE OVERNIGHT AND WEDNESDAY MORNING AS THE LOW FILLS OUT WEST AND
AND THE GRADIENT WEAKENS. A BRIEF BREAK FROM THE PRECIPITATION IS
LIKELY OVERNIGHT WITH FOG AND LOW STRATUS A POSSIBILITY WHERE WINDS
LIE DOWN. THE NEXT WAVE BRINGS ANOTHER SHOT OF RAIN AND SNOW
WEDNESDAY AFTERNOON BEFORE A SLOW CLEARING AND COOLING BY THE END OF
THE WEEK.

OVER THE ALEUTIANS AND BERING SEA...RAIN AND SNOW SHOWERS WILL
PREVAIL UNDER THE VERY BROAD CYCLONIC CIRCULATION. THE 975 MB LOW
WEAKENS TONIGHT AS IT DRIFTS TOWARD THE ALASKA PENINSULA WHERE IT
WILL DISSIPATE BY THURSDAY MORNING. SMALL CRAFT TO MINIMUM GALE
NORTHWESTERLY FLOW WILL AGAIN PREDOMINATE OVER THE BERING SEA BY MID
WEEK ALONG WITH THE VERY TYPICAL WEAK COLD AIR ADVECTION SNOW
SHOWERS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE WARNING...130 172.
FIRE WEATHER...NONE.

AB MAR 12