Small Craft Advisory 550, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
400 AM AKDT WED JUL 15 2009

.ANALYSIS AND UPPER LEVELS...
A LOW OVER CANADA IS TRAILING A COLD FRONT ACROSS THE ALCAN BORDER
THAT WILL MOVE TOWARD THE EASTERN ALASKA RANGE AND THEN INTO THE
COPPER RIVER VALLEY TODAY AS IT DISSIPATES. AHEAD OF AND WITH THE
FRONT THE ATMOSPHERE IS STILL CONDUCIVE TO THUNDERSTORMS AND SHOWERS.
THE UPPER LEVEL RIDGE OVER SOUTH CENTRAL IS RAPIDLY WEAKENING AS WE
MOVE INTO A MORE SHOWERY REGIME FOR THE END OF THE WEEK. A TRANSITORY
RIDGE OVER THE EASTERN BERING WILL WEAKEN TONIGHT AS A LOW CURRENTLY
AFFECTING THE WESTERN ALEUTIANS MOVES INTO THE WESTERN BERING.

.MODEL DISCUSSION...
MODELS REMAIN IN GOOD AGREEMENT THROUGH THE EARLY WEEKEND. THE
GFS/NAM SOLUTION WAS USED IN THE SHORT TERM...WITH A BLEND TOWARD
GFS/HPC IN THE EXTENDED.

.SHORT TERM FORECAST...
.SOUTHCENTRAL...
WEAKENING RIDGE HAS ALLOWED MORE STRATUS TO INFILTRATE SOUTHCENTRAL
THE PAST COUPLE OF MORNINGS. EXPECT THIS TREND TO CONTINUE WITH SOME
CLEARING BY AFTERNOON. AS THE COLD FRONT APPROACHES THE ALASKA RANGE
LOOK FOR IT TO TRIGGER MORE SHOWERS AND THUNDERSTORMS INTO THE COPPER
RIVER AND SUSITNA VALLEYS TODAY. BY THE WEEKEND MODELS ARE INDICATING
A FRONTAL INTRUSION BRINGING SOME WETTING RAIN TO THE COASTAL AREAS
AND EVEN UP INTO THE MAT-SU BY SAT EVENING.

.SOUTHWEST...
SHOWERS FROM A DISSIPATED FRONT WILL REMAIN ACROSS THE REGION TODAY.
THURSDAY WILL BE RELATIVELY QUIET WITH SOME STRATUS AND FOG ACROSS
THE AREA BEFORE A FRONT ASSOCIATED WITH THE LOW NEAR THE WESTERN
ALEUTIANS BRINGS MORE RAIN THU NIGHT AND FRI.

.BERING SEA AND ALEUTIANS...
TRAINSITORY HIGH PRESSURE WILL KEEP CLOUDY AND FOGGY CONDITIONS
ACROSS THE PRIBS AND AK PENN TODAY. THE CURRENT LOW AFFECTING THE
WESTERN BERING AND WESTERN ALEUTIANS WILL MOVE EAST TODAY BRINGING
RAIN AND SMALL CRAFT WINDS ACROSS THE CENTRAL AND EASTERN ALEUTIANS.
EXPECT LOW CLOUDS AND SHOWERS TO PERSIST THROUGH FRIDAY.

.LONG TERM FORECAST...

LOOK FOR COOLER..MORE SEASONABLE TEMPS BY THE END OF THE WEEKEND AS A
LONGWAVE TROUGH AFFECTS THE AREA AND THE THERMAL TROUGH SHIFT NORTH
OF THE ALASKA RANGE. EXPECT SHOWERY ACTIVITY WITH SOME STEADY RAIN
MIXED IN BY LATE WEEKEND AND INTO NEXT WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALES 175 176
FIRE WEATHER...NONE

RW JUL 09