Small Craft Advisory 714, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
415 AM AKDT WED SEP 17 2008

.ANALYSIS AND UPPER LEVELS...
THIS MORNING...THE MAIN FEATURE OF INTEREST IS A 993 MB LOW PRESSURE
IN PRINCE WILLIAM SOUND. THIS LOW HAS BROUGHT ABUNDANT RAINFALL TO
SOUTHCENTRAL INCLUDING MANY INLAND AREAS OF THE COOK INLET REGION
WHICH ARE NORMALLY DRIER. THIS LOW WILL DISSIPATE BY THIS AFTERNOON
WITH RAIN TAPERING OFF FROM SOUTHWEST TO NORTHEAST. HOWEVER...THERE
IS A STRENGTHENING LOW PRESSURE SOUTH OF DUTCH HARBOR MOVING RIDING
THE JET STREAM EAST. THIS LOW WILL CONTINUE TO STRENGTHEN AS IT
MOVES INTO THE WESTERN GULF OF ALASKA LATER TONIGHT...KEEPING THE
WEATHER ACTIVE OVER THE SOUTHERN MAINLAND. HIGH PRESSURE EXISTS OVER
THE FAR WESTERN BERING/ALEUTIANS WITH NORTHWEST FLOW OVER MOST OF
THE BERING/ALEUTIANS ON THE EAST SIDE OF THE HIGH.

.MODEL DISCUSSION...
MODELS ARE DOING OKAY...NOT GREAT...NOT TERRIBLE. MAIN FORECAST
ISSUE IS THE LOW RIDING SOUTH OF THE EASTERN ALEUTIANS AND REACHING
THE KODIAK ISLAND AREA TONIGHT. MODELS HAVE BEEN WOBBLING A LITTLE
ON WHETHER THE LOW GOES JUST WEST OF SHELIKOF STRAIT OF STAYS OVER
KODIAK. WE ARE GOING WITH THE EASTERN ENVELOPE OF MODEL
SOLUTIONS...TAKING THE LOW DIRECTLY OVER KODIAK ISLAND. THE LOW THEN
STALLS OUT AROUND KODIAK ISLAND...BUT MODELS DISAGREE AS TO HOW LONG
IT STALLS OUT. WE ARE GOING WITH THE IDEA THAT THE LOW KICKS OUT A
LITTLE FASTER AND TOWARD SEWARD...WHICH IS PRETTY CONSISTENT WITH
WHAT THE PREVIOUS FORECAST PACKAGE WENT WITH. FOR THE LONG
TERM...FAVORING THE 0Z ECMWF OVER THE 0Z GFS...AS THE 0Z GFS WAS
MUCH MORE INCONSISTENT WITH ITS PREVIOUS RUN AND THE 0Z ECMWF WAS
MORE CONSISTENT WITH THE PREVIOUS FORECAST PACKAGE.

.SHORT TERM FORECAST...
SOUTHCENTRAL...
THE PRINCE WILLIAM SOUND LOW PRESSURE WILL DISSIPATE TODAY...AS RAIN
WILL CONTINUE TO TAPER OFF FROM SOUTHWEST TO NORTHEAST AS THE UPPER
LEVEL TROUGH KICKS THROUGH. PARTIAL CLEARING WILL OCCUR OVER SOME
AREAS TODAY BEFORE THE NEXT SYSTEM HOT ON ITS HEELS BEGINS TO AFFECT
SOUTHCENTRAL TONIGHT. THE NEXT SYSTEM IS A STRONG LOW MOVING
NORTHEAST INTO THE WESTERN GULF...REACHING KODIAK TONIGHT AND MAXING
OUT AT AROUND 982 MB. THIS LOW THEN NEARLY STALLS OUT AND EVENTUALLY
SLOWLY KICKS OUT NORTHEAST FROM KODIAK AND ACROSS THE FAR NORTHERN
GULF THURSDAY NIGHT OR FRIDAY. WHAT THIS ALL MEANS IS PROLONGED RAIN
AND WINDS FOR MUCH OF THE REGION. THE RAIN WILL RETURN TO KODIAK
THIS AFTERNOON AND TO THE KENAI THIS EVENING. THIS
SYSTEM...HOWEVER...WILL BE DIFFERENT THAN THE LAST SYSTEM IN THAT
NOT A WHOLE LOT OF RAIN IS EXPECTED TO MAKE IT OVER THE KENAI AND
CHUGACH MOUNTAINS TO THE CORRIDOR FROM THE WESTERN KENAI TO
ANCHORAGE TO PALMER. ALSO...STRONG WINDS CAN BE EXPECTED IN THE
USUAL CHANNELED AREAS LIKE TURNAGAIN ARM AND PORTAGE VALLEY. LITTLE
OR NO CLEARING IS EXPECTED THROUGH FRIDAY WITH THE ONSHORE FLOW
CONTINUING.

SOUTHWEST MAINLAND...
A WEAK RIDGE OF HIGH PRESSURE IS OVER THE SOUTHWEST MAINLAND THIS
MORNING WITH SOME LOW CLOUDS AND FOG. THE LOW MOVING INTO THE
WESTERN GULF WILL SPREAD ABUNDANT RAIN OVER THE MOUNTAINS BEGINNING
THIS AFTERNOON AND EVENING. THE RAIN WILL MAINLY INTO THE BRISTOL
BAY AREA ALONG WITH GUSTY NORTHERLY WINDS. RAIN WILL GRADUALLY TAPER
OFF TO SCATTERED SHOWERS ON FRIDAY...BUT ONSHORE WESTERLY FLOW WILL
KEEP CONDITIONS GLOOMY.

BERING SEA/ALEUTIANS...
THE LOW SOUTH OF DUTCH HARBOR EARLY THIS MORNING WILL QUICKLY KICK
OUT OF THE REGION BY TONIGHT AS THE LOW MOVES EAST TO KODIAK...AND
FAIRLY STRONG SHOWERY NORTHWEST FLOW WILL SET UP OVER THE CENTRAL TO
EASTERN BERING/ALEUTIANS AND ALASKA PENINSULA. WILL HAVE TO WATCH
FOR ESPECIALLY GUSTY NORTHWEST WINDS SETTING UP SOUTH OF THE ALASKA
PENINSULA. ZONAL FLOW WILL GRADUALLY SET INTO THE REGION THURSDAY
NIGHT AND FRIDAY.

.LONG TERM FORECAST...
THE LOW IN THE NORTHERN GULF IS EXPECTED TO EVENTUALLY DISSIPATE IN
THE NORTHEAST GULF LATE SUNDAY OR MONDAY...WITH HIGH PRESSURE
TENTATIVELY EXPECTED TO BUILD INTO THE MAINLAND EARLY NEXT WEEK FOR
THE FIRST TIME IN FOREVER. NOT TOTALLY SOLD ON THIS YET...BUT THE
POTENTIAL EXISTS FOR A COUPLE OF NICE FALL DAYS EARLY NEXT WEEK.
MOST OF THE UNSETTLED WEATHER EARLY NEXT WEEK IS EXPECTED TO BE OUT
IN BERING.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE WARNING ZONES 120 125 130 132 138 140 150 155 351 352.
FIRE WEATHER...NONE.

FOISY SEP 08