Gale Warning 284, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
233 PM AKDT THU MAR 25 2010

.ANALYSIS AND UPPER LEVELS...THE UPPER LEVEL HIGH THAT IS CENTERED TO
THE NORTHWEST OF MAINLAND ALASKA CONTINUES TO SLOWLY WEAKEN AND MOVE TO
THE NORTHWEST. A TROUGH REGION STRETCHES FROM RUSSIA TO THE GULF OF
ALASKA. WITHIN THIS TROUGH REGION A WEAK UPPER LEVEL LOW IS CENTERED TO
THE NORTH OF ADAK ISLAND WHILE A SECOND MORE POTENT LOW IS LOCATED IN
THE NORTH PACIFIC TO THE SOUTHEAST OF ADAK ISLAND. AN UNDULATING 150 KT
JET IS LOCATED SOUTH OF THE NORTH PACIFIC LOW.

.AT THE SURFACE...A BEAUTIFULLY WRAPPED OCCLUDED 968 MB LOW IS CURRENTLY
LOCATED ABOUT 500 MILES SOUTHEAST OF DUTCH HARBOR. THE UPPER LEVEL 150
KT JET IS PROVIDING UPPER LEVEL SUPPORT FOR THIS FEATURE. WITHIN THE
SOUTHERN BERING SEA...THERE ARE TWO MUCH WEAKER 993 MB LOWS WITH ONE LOW
JUST TO THE NORTHWEST OF BRISTOL BAY AND A SEPARATE LOW NORTH OF ADAK
ISLAND. MEANWHILE...SURFACE HIGH PRESSURE SPREADS ACROSS FROM NORTHERN
MAINLAND ALASKA AND NORTH OF RUSSIA.

MODEL DISCUSSION...IN THE SHORT TERM MODELS ARE IN GENERAL AGREEMENT IN
THE MOVEMENT OF THE NORTH PACIFIC SURFACE LOW INTO THE GULF OF ALASKA.
HOWEVER...MODELS DISAGREE IN THE POSITION OF A DEVELOPING SURFACE LOW
THAT BEGINS TO MOVE ALONG THE SOUTHERN EDGE OF THE WESTERN ALEUTIAN
ISLANDS BY FRIDAY. THE LARGE DISCREPANCY BETWEEN THE MODELS APPEARS TO
BE PARTLY DUE TO HOW EACH MODEL IS DEPICTING THE UPPER LEVEL JET
SUPPORT. THE GFS INDICATES A JET MAX FARTHER EAST...WHILE THE ECMWF
FAVORS A JET MAX FARTHER WEST. THIS RESULTS IN A MORE WESTERN POSITION
FOR THE LOW PRESSURE IN THE ECMWF SOLUTION.  THE ECMWF APPEARS TO BE THE
MOST CONSISTENT SOLUTION AND WAS CHOSEN FOR THE SHORT TERM WEST FORECAST
AREA AND LONG TERM FORECASTS.

.SHORT TERM FORECAST...
.SOUTHCENTRAL...WITH NO DOMINANT LOW IN THE REGION OVER THE NEXT
DAY...WEATHER WILL REMAIN RELATIVELY QUIET TODAY AND TOMORROW.  A
SHORTWAVE WILL BRING THE POSSIBILITY OF SHOWERS TO THE SOUTHERN AND
EASTERN PORTIONS OF THE KENAI PENINSULA AND KODIAK ISLAND TONIGHT AND
TOMORROW. A CHANCE FOR MORE PERSISTENT PRECIPITATION ALONG THE GULF
COAST ARRIVES FRIDAY NIGHT AS A POTENT 966 MB LOW APPROACHES THE GULF OF
ALASKA. HOWEVER...DOWNSLOPING WILL KEEP THE PRECIPITATION AMOUNTS MUCH
LOWER IN INLAND AREAS.

.SOUTHWEST MAINLAND...SCATTERED SNOW AND RAIN SHOWERS WILL CONTINUE TO
IMPACT THE REGION TODAY BUT WILL SLOWLY TAPER OFF AS AN UPPER LEVEL
SHORTWAVE MOVES OUT OF THE REGION.  WEATHER WILL BE GENERALLY QUIET THIS
WEEKEND...AS THE LOWS OVER THE BERING DISSIPATE AND THE GULF LOW REMAINS
SOUTH OF THE REGION.

.THE BERING SEA AND ALEUTIANS...A POTENT 969 MB LOW WILL APPROACH SHEMYA
BY FRIDAY BRINGING GALE FORCE WINDS AND SNOW MIXED WITH RAIN. THE SYSTEM
WILL MOVE QUICKLY TO THE SOUTHEAST BRINGING GALE FORCE WINDS AND STEADY
SHOWERS TO THE CENTRAL ALEUTIANS EARLY SATURDAY MORNING.  THIS LOW
PRESSURE WILL THEN DIVE SOUTH OF THE ALEUTIAN ISLANDS DECREASING WINDS
ALONG THE ALEUTIAN CHAIN AND WITH ISOLATED SNOW SHOWERS.

.LONG TERM FORECAST...AN ACTIVE PATTERN WILL REMAIN IN PLACE FOR AT
LEAST THE NEXT WEEK. MODELS INDICATE THAT THE JET STREAM WILL BE
RELATIVELY CLOSE TO ALASKA OVER THE NEXT WEEK AND REMAIN FAIRLY STRONG.
AS A RESULT...MUCH STRONGER LOW PRESSURE SYSTEMS WILL BE ABLE TO DEVELOP
AND IMPACT THE FORECAST REGION.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 120 130 132 138 150 155 176
FIRE WEATHER...NONE.

ELN MAR 10