Small Craft Advisory 531, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM ADT TUE JUN 19 2007

.MODEL DISCUSSION...GFS/UKMET SYNOPTIC INITIALIZATIONS IN FAIR
AGREEMENT AND HAVE REASONABLE FORECAST TREND THROUGH 60 HR.
CONFIDENCE NOT VERY HIGH OUT WEST BEYOND 60 HRS AS MODEL WILL HAVE
HARD TIME RESOLVING WEAK OPEN WAVES OVER THE BERING SEA.

.UPPER AIR...BLOCKING PATTERN WITH RIDGE OVER THE MAINLAND AND LOW
PRESSURE IN THE NE PACIFIC WILL START TO WEAKEN LATER THIS WEEK.
UKMET/GFS TEND TO DIG TROUGH SOUTH FROM THE POLE TO A CENTER OVER THE
EASTERN BERING SEA. THIS THEN TENDS TO WEAKEN THE RIDGE AND PUSH IT
FURTHER SE. THE RESULTING SW FLOW OVER THE MAINLAND WILL USHER IN A
PATTERN CHANGE TO THE SOUTHCENTRAL MAINLAND FROM WARM AND DRY TO COOL
AND MOIST.

.SURFACE...
.EAST...THERMAL TROUGH INTENSIFIES TODAY AND WED. HOWEVER...ALSO
EXPECT FAIRLY DRY AIR TO SPREAD EAST FROM THE YUKON OVER SOUTHCENTRAL
ALASKA TODAY AND WED. THIS WILL PUT A CAP ON SIGNIFICANT CONVECTION
OVER THE NEXT COUPLE OF DAYS...THOUGH MAY SEE SOME ISOLATED TSTM
ACTIVITY ALONG THE TALKEETNA MOUNTAINS AND NORTHERN COPPER THIS
EVENING. CURRENT SAT AND SURFACE OBSERVATIONS SHOW DRYING CONDITIONS
MOVING INTO THE COPPER RIVER. THE PROFILER IN THE COPPER RIVER SHOWS
SIGNIFICANT INCREASE IN NE WINDS FROM 2KM-5KM THIS AFTERNOON. MODELS
ARE SHOWING NE WINDS AND RESULTING DRYING DOWNSLOPE CONDITIONS
SPREADING ACROSS SOUTHCENTRAL TONIGHT AND WED. RED FLAG CONDITIONS
FOR LOW RH VALUES LIKELY OVER THE COPPER RIVER/AND PORTIONS OF
SOUTHCENTRAL THIS AFTERNOON AND WED.  SOUTHCENTRAL SHOULD SEE A WEAK
MARINE PUSH THU AND MORE SO FRI AND SAT.

.WEST...UNSTABLE CONDITIONS LIKELY OVER THE EASTERN KUSKOKWIM VALLEY
AND INLAND/NORTH BRISTOL BAY ZONE THIS AFTERNOON/EVE.SHOULD BE
UNSTABLE ENOUGH TO KICK OFF ISOLATED THUNDERSTORMS ALONG THE ALASKA
RANGE/NORTHERN ALEUTIAN RANGE. THERMAL TROUGH LIKELY TO HOLD UNSTABLE
CONDITIONS THESE AREAS THROUGH WED. CONDITIONS SHOULD BECOME MORE
STABLE THU AND FRI AS BERING SEA RIDGE BREAKS DOWN AND ALLOWS COOLER
AIR AND MOISTURE TO SPREAD EAST FROM THE BERING SEA. COASTAL SW
ALASKA WILL CONTINUE IN THE MARINE LAYER THROUGH WED. RAIN LIKELY
SPREADING TO COASTAL LOCALS THU. CLOUDY CONDITIONS WITH LOW CLOUDS
AND FOG WITH PERIODS OF LIGHT RAIN SHOULD BE THE GENERAL RULE OVER
THE BERING SEA/ALEUTIANS THROUGH THU.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...RED FLAG WARNINGS ZONES 141 AND 145. RED FLAG WATCHES
ZONES 111 AND 121.

RMC JUN 07