Flood in Alaska, June 25 to 26, 2004

SOUTHEAST ALASKA FORECAST DISCUSSION
1045 AM ADT THU JUN 24 2004

.SYNOPSIS...
.SHORT RANGE...HIGH PRESSURE STILL DOMINATING THE WEATHER PATTERN
IN THE SHORT RANGE. FEATURES ARE BEGINNING TO SHIFT SLIGHTLY
THOUGH AS UPPER HIGH OVER THE PANHANDLE BECOMES MORE CUTOFF OVER
THE YUKON AND UPPER LOW MOVES TOWARD THE SOUTHERN B.C. COAST.
THE RESULTING INCREASE IN E-SE FLOW WILL BRING MORE MOISTURE AND
CONVECTIVE POTENTIAL TO THE AREA FRI AFTERNOON INTO FRI NIGHT.
LOWER LEVELS REMAIN VERY WARM AND MODEL CONVECTIVE PARAMETERS ARE
VERY HIGH FOR SOUTHEAST ALASKA SO ISOLATED THUNDERSTORMS POSSIBLE
OVER SOUTHERN ZONES LATE FRI AND INTO FRI NIGHT. ETA SHOWS SECOND
CAPE BULLSEYE OVER NORTHERN INNER CHANNELS LATE FRI WHICH MIGHT
BE ENOUGH TO BRING ISOLATED STRONG SHOWERS TO JUNEAU AREA FRI
EVENING/NIGHT.

OTHER FORECAST PROBLEM IS GLFAK FOG AND STRATUS THAT MOVED INTO
SOUTHERN ZONES AND OCEAN ENTRANCES LAST NIGHT. CLOUDS ARE IN THE
PROCESS OF BURNING OFF OVER THE INNER CHANNELS WITH SOUTHERN
ZONES THE LAST TO GO DURING THE AFTERNOON. EXPECT ANOTHER PUSH
ONSHORE TONIGHT...BUT NOT AS STRONGLY INTO THE INNER CHANNELS AS
SURFACE TROUGH DEVELOPS MORE ALONG THE COAST THAN INLAND.

RECORD-BREAKING STRING OF HOT WEATHER WILL CONTINUE TODAY AND
FRI. MODELS SHOW EVEN WARMER TEMPS FOR FRI THAN TODAY WITH
WIDESPREAD 80S OVER NORTHERN AND CENTRAL PANHANDLE. A LITTLE
COOLER OVER SOUTHERN ZONES WITH MORE CLOUD COVER AND CONVECTIVE
POTENTIAL...BUT STILL GETTING UP INTO THE 70S.

.LONG RANGE...LITTLE CHANGE TO SYNOPTIC PATTERN THROUGH THE
MIDDLE OF NEXT WEEK. UPPER HIGH DOES SHIFT A BIT TO NORTH AND
INTO INTERIOR ALASKA THAT WILL ALLOW BETTER CHANCE OF ENERGY TO
MOVE INTO FAR SOUTHERN PANAHNDLE. A SERIES OF UPPER PASSING SOUTH
OF FORECAST AREA EXPECTED TO ROTATE WEAK TROUGH THROUGH AREA
FRIDAY NIGHT. INVERTED/THERMAL TROUGH WILL ALSO PERSIST ACROSS
SOUTHEAST ALASKA WITH MODELS IN GENERAL AGREEMENT THAT A SMALL
LOW WILL FORM ON TROUGH AND PASS THROUGH PANHANDLE FRIDAY
NIGHT-SATURDAY MORNING. DO EXPECT SOME MID CLOUDS AND SLIGHT
CHANCE SHWR OR TSTM. WEST OF THERMAL TROUGH WILL HAVE TO DEAL
WITH MARINE LAYER THAT WILL MOVE ONSHORE AT NIGHT AND DISSIPATE
OVER LAND DURING MORNING. BY SUNDAY THERMAL TROUGH MOVES WEST
INTO COASTAL AREA FOR MORE DRY WEATHER ACROSS SOUTHEAST ALASKA
THROUGH WED OF NEXT WEEK. TEMPERATURES TO REMAIN IN 70S TO LOWER
80 FOR INNER CHANNELS WITH COOLER MARITIME CONDITION ALONG
IMMEDIATE COAST.

GLACIAL RIVERS REMAIN AT PEAK SUMMER LEVELS THROUGH THIS WEEKEND.
ALSEK REACHED ACTION STAGE THIS MORNING WITH ONLY SLIGHT
INCREASES EXPECTED THROUGH SATURDAY TO BRING RIVER LEVEL TO NEAR
BANKFULL BUT AT THIS TIME BELOW FLOOD STAGE THROUGH SATURDAY.

TULSEQUAH GLACIAL DAM MAY HAVE RELEASED THIS MORNING NOTING A 1.2
FOOT INCREASE IN STAGE AND 2 DEGREE C DECREASE IN WATER
TEMPERATURE LAST NIGHT. SHOULD HAVE CONFIRMATION ON THIS EVENT
WITH NEXT ROUND OF OBS DUE AT 1145 AM. WILL ISSUE RVS FOR TAKU
RIVER BY THIS AFTERNOON. HAVE NO DATA UPSTREAM AND WILL BE
DIFFICULT TO PREDICT CREST ON TAKU BUT FOR NOW EXPECT TYPICAL
BANKFULL CONDITIONS WITH EVENT.

FIRE DANGER RATINGS INCREASING ACROSS PANHANDLE. CURRENTLY LOW
LEVEL MARINE MOISTURE KEEPING RH WELL ABOVE THRESHOLDS. WITH
APPROACHING WEAK DISTURBANCE COULD SEE BURST OF DRIER AIR IN
EASTERLY FLOW ON SATURDAY MORNING AND RH DOWN TO 20 PERCENT
THROUGH NORTHERN INNER CHANNELS. ALSO WILL NEED TO MONITOR FOR
ISOLATED TSTMS THAT HAVE POTENTIAL TO BE DRY.

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC...RVS FOR TAKU/TELSEQUAH OUTBURST AND HIGH FLOWS ON OTHER
         GLACIAL RIVERS
MARINE...NONE