Small Craft Advisory 571, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM ADT THU JUL 5 2007

.MODEL DISCUSSION...
MODELS ARE GENERALLY IN GOOD AGREEMENT WITH SOME DIVERGENCE OF
SOLUTIONS AFTER FRIDAY NIGHT. THE GFS STILL APPEARS TO BE THE BETTER
MODEL BECAUSE IT HAS GOOD RUN-TO-RUN CONSISTENCY.

.ANALYSIS AND UPPER LEVELS...
THE UPPER AIR PATTERN HAS CHANGED MUCH OVER THE LAST FEW DAYS WITH
THE MAIN UPPER HIGH OVER THE CHUKCHI SEA AND THE MAIN UPPER LOW NEAR
THE SOUTHERN GULF OF ALASKA. A NEW UPPER LOW OVER THE WESTERN
ALEUTIANS HAS OPENED A TROUGH ALONG THE ALEUTIAN CHAIN.

AT THE SURFACE...THE THERMAL TROUGH REMAINS OVER THE CENTRAL AND
SOUTHWEST INTERIOR. THE STABILITY INDEXES ARE STILL FAIRLY LOW OVER
THE KUSKOKWIM VALLEY AND THE KUSKOKWIM DELTA WITH THUNDERSTORMS
MOSTLY DEVELOPING OVER THESE AREAS LATE TODAY.

THE LOW OVER THE SOUTHERN GULF HAS WEAKENED AND IT APPEARS THAT THE
LAST IN THE SERIES OF EASTERLY WAVES IS MOVING THROUGH PRINCE WILLIAM
SOUND AND THE KENAI PENINSULA. THE RIDGE ALONG THE GULF COAST HAS
GOTTEN A BIT STRONGER SINCE YESTERDAY. THE AREA OF HIGH PRESSURE
PERSISTS OVER THE BERING SEA.

.SHORT TERM FORECAST...
SOUTHCENTRAL ALASKA...
THE STAGNANT PATTERN OVER THE GULF IS FINALLY BREAKING. THE LOW OVER
THE SOUTHERN GULF WILL CONTINUE TO WEAKEN AND WILL DISSIPATE BY
SATURDAY WHILE THE RIDGE ALONG THE GULF COAST WILL STRENGTHEN AND
SPREAD IN THE GULF. DRIER AIR FROM WESTERN CANADA SHOULD BREAKUP SOME
OF CLOUDS OVER SOUTHCENTRAL FRIDAY WITH SCATTERED SHOWERS DEVELOPING
IN THE LATE AFTERNOON AND EVENING. SATURDAY SHOULD BE SIMILAR TO
FRIDAY.

SOUTHWEST ALASKA...
THE THERMAL TROUGH OVER THE KUSKOKWIM DELTA AND NORTHWESTERN
KUSKOKWIM VALLEY WILL REMAIN OVER THE CENTRAL TO NORTHERN SECTIONS OF
SOUTHWEST ALASKA THROUGH SATURDAY. STABILITY INDEXES WILL RISE
THROUGH SATURDAY WITH SHOWERS AND THUNDERSTORMS ACTIVITY LESSING OVER
THE NEXT FEW DAYS.

BERING SEA AND ALEUTIANS...
THE BERING SEA HIGH WILL REMAIN OVER THE AREA THROUGH SATURDAY WHICH
WILL KEEP THE TRACK OF ANY NEW WEATHER SYSTEM SOUTH OF THE ALEUTIANS.
NO SIGNIFICANT WEATHER IS EXPECTED IN THIS AREA.

.LONG TERM FORECAST...
THE OVERALL PATTERN WILL BEGIN TO CHANGE OVER THE NEXT 5 DAYS. THE
UPPER HIGH OVER THE THE CHUKCHI SEA WILL MOVE EAST ACROSS NORTHERN
ALASKA AND WILL LINK UP WITH A RIDGE OVER WESTERN CANADA TUESDAY. THE
UPPER LOW OVER THE SOUTHERN GULF WILL WEAKEN AND MOVE INTO BRITISH
COLUMBIA SUNDAY. ANOTHER LOW WILL OVER THE WESTERN ALEUTIANS WILL
MOVE EAST AND BECOME NEARLY STATIONARY SOUTH OF KODIAK ISLAND
TUESDAY. THIS OPEN MOST OF THE SOUTHERN MAINLAND UP TO A MOIST SOUTH
TO SOUTHEAST FLOW COMING OFF THE GULF OF ALASKA BY THE BEGINNING OF
NEXT WEEK.

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

NM JUL 07