Small Craft Advisory 589, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM ADT MON JUL 16 2007

.ANALYSIS AND UPPER LEVELS...

UPPER LEVEL LOW OVER NORTHERN AK THIS MORNING EXTENDS SOUTHWEST TO
THE KUSKOKWIM. UPPER LOWS ARE ALSO SOUTH OF THE CENTRAL ALEUTIANS AND
POKING TOWARD SE AK. UPPER RIDGES PERSIST OVER THE EASTERN BERING AND

THE NORTH GULF COAST. AT THE SURFACE...RIDGES ARE OVER THE BERING AND
SW AK...WITH A TROUGH ALONG THE NORTH GULF COAST AND A LOW SOUTH OF
THE CENTRAL ALEUTIANS.

.MODEL DISCUSSION...

MODELS AGREE THAT A PATTERN CHANGE IS IN PROGRESS...WITH THE SURFACE
HIGH MIGRATING INTO THE BERING AND A NORTH PACIFIC LOW HEADING TO
BRISTOL BAY AND THE AKPEN. WHILE THAT IS OCCURRING...AN EASTERLY WAVE
WILL MOVE INTO THE COPPER RIVER BASIN AND POSSIBLY A BIT FARTHER.
THIS WILL THEN LOSE INFLUENCE AS THE FRONT ASSOCIATED WITH THE
WESTERN LOW MOVES ACROSS THE AK AND ALEUTIAN RANGES. FORECASTS ONCE
AGAIN LEAN HEAVILY ON THE GFS WHICH SEEMS TO HAVE A REASONABLE HANDLE
ON THE AFOREMENTIONED ELEMENTS...IN PARTICULAR BRINGING THE NORTH
PACIFIC LOW AS FAR NORTH AS THE WESTERN AK PEN BEFORE IT DIVES
SOUTHEAST INTO THE GULF.

SHORT TERM FORECAST...

IN THE WEST...THE INITIAL LOW BRINGS RAIN AND SMALL CRAFT WIND TO THE
ALEUTIANS TODAY...AND THEN AS AN INTENSIFYING WAVE MOVES PAST THE
INITIAL LOW TONIGHT...GALES WILL AFFECT THE EASTERN ISLANDS AND THE
AKPEN THROUGH TUE. SHOWERS WILL PERSIST IN THE AREA THROUGH WED. HIGH
PRESSURE WILL THEN BUILD INTO THE BERING...IMPEDING THE NORTHWARD
PROGRESS OF THE NEXT LOW. THIS WILL KEEP RAIN AND GALES MAINLY ALONG
THE WESTERN AND CENTRAL PORTIONS OF THE CHAIN THU NIGHT AND FRI.

OVER SW AK...THE SOUTHWESTERN EXTENSION OF THE UPPER LOW MAY TRIGGER
A FEW SHOWERS THIS AFTERNOON. THIS EXTENSION THEN CUTS OFF OVER THE
AREA TONIGHT AND MAY HELP A FEW MORE SHOWERS DEVELOP OVER MOUNTAINS
TUE. BY WED THE BERING-ALEUTIAN LOW MOVES INTO THE AREA WITH CLOUDS
AND SHOWERS LASTING AT LEAST UNTIL THE LOW MOVES INTO THE GULF THU.
MOUNTAINS WILL BE THE FOCUS OF MORE SHOWERS FRI.

SOUTH AND EAST OF THE AK RANGE...RESIDUAL OVERNIGHT CLOUDS SHOULD
DISSIPATE OVER MUCH OF THE AREA TODAY. THE APPROACH OF THE EASTERLY
WAVE SHOULD BE SUFFICIENTLY SLOW TO ALLOW ANOTHER WARM AND DRY DAY
OVER THE COPPER RIVER BASIN. THIS WILL GIVE WAY TO RAIN TUE IN THAT
AREA WITH MOUNTAIN SHOWERS ELSEWHERE. THE WAVE AND ASSOCIATED RAIN
WILL REACH THE TALKEETNAS TUE NIGHT. AT THAT POINT THE FLOW BEGINS TO
BE DOMINATED BY THE BERING-ALEUTIAN LOW AND THE RIDGING AHEAD OF THIS
FEATURE WILL DRY THINGS OUT EXCEPT ALONG MOUNTAINS AND IN PARTICULAR
THE WRANGELLS THROUGH FRI.

.LONG TERM FORECAST...

LITTLE CHANGE OUT WEST AS THE LOW REMAINS NEAR THE ALEUTIANS THROUGH
THE WEEKEND. A WAVE DIVING DOWN THE WEST COAST BRINGS ANOTHER ROUND
OF SHOWERS TO THE SOUTHWEST FOR THE WEEKEND. A THERMAL TROUGH SETS UP
NEAR THE ALCAN FOR WEEKEND AFTERNOON AND EVENING SHOWERS OVER THE
COPPER RIVER BASIN...AND ALONG THE AK RANGE AND TALKEETNAS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALES 155 165
FIRE WEATHER...

DS JUL 07