Gale Warning 131, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
1100 AM ADT TUE APR 15 2008

.SHORT RANGE...UKMET LAYER RH FIELD IS A GOOD FIT TO SATELLITE WV
IMAGERY BUT GFS IS A LITTLE BETTER WRT FEATURES SOUTH OF THE
CENTRAL GULF AND NEAR THE ALEUTIANS. BELIEVE UKMET AND GFS HAVE
BETTER DEPICTION OF SHORT WAVE RIDING UP THE WEST SIDE OF THE
UPPER LEVEL RIDGE BASED ON IR SATELLITE IMAGERY. OVERALL VORT
PATTERN FAVORS UKMET...ESPECIALLY SOUTH OF THE ALEUTIANS. ALL
MODELS TOO WEAK ON STRENGTH OF THE NW JET OVER NE GULF AND
PANHANDLE THIS MORNING BUT GFS IS A LOT CLOSER THAN OTHERS.
SCATTEROMETER WINDS INDICATING THAT NAM AND ECMWF SURFACE WINDS
INITIALIZED BEST. UKMET AND GFS SURFACE PRESSURE FIELDS NEARLY
IDENTICAL THROUGH 16/12Z. AFTERWARDS...GFS CONTINUES TO TRACK THE
LOW TO THE EAST WHEREAS UKMET ABRUPTLY STOPS IT NEAR PRINCE
WILLIAM SOUND AND IN THIS RESPECT IS THE OUTLIER WHEN COMPARED TO
THE NAM AND ECMWF AS WELL. WILL BLEND IN SOME UKMET EARLY...NUDGE
TO CURRENT GFS IN THE MIDDLE...AND THEN BLEND GFS WITH ECMWF AT
THE END IN ORDER TO SLOW DOWN THE EASTWARD PROGRESS A LITTLE.

SOUTHWEST FLOW AT ALL LEVELS AND WARM AIR ADVECTION WILL RESULT
IN SNOW INSTEAD OF RAIN THROUGHOUT THE PANHANDLE TONIGHT. COLD
AIR ADVECTION BEGINNING TOMORROW FIRST FROM THE GULF AND THEN
FROM THE YUKON WILL INCREASE THE THREAT OF SOME MIXED PRECIP AS
WE HEAD INTO THE LONG RANGE FORECAST PERIOD. HAVE DELAYED THE
PROGRESS OF POP ACROSS THE FORECAST DOMAIN TO REFLECT THE IDEA
THAT THIS SYSTEM WILL TRACK A LITTLE SLOWER THAN GFS IS
DEPICTING.

AM EXPECTING SW SMALL CRAFT WINDS ALONG THE OUTER COAST TONIGHT
WITH A MARGINAL WESTERLY GALE IN THE OFFSHORE MARINE ZONE. SHOULD
BE SEEING SEAS BUILD TO 15 FEET WITH A 10 SECOND PERIOD OR SO
RIGHT UP TO THE OUTER COAST BY TOMORROW AFTERNOON AS A RESULT. ON
THE INSIDE...SOUTHERLY SMALL CRAFT WINDS WILL DEVELOP IN THE
SOUTHERN INNER CHANNELS THROUGH THE NIGHT WITH THE NORTHERN INNER
CHANNELS FOLLOWING SUIT EARLY TOMORROW MORNING. FCF

.LONG RANGE...
ALL EVIDENCE FROM EVERY MODEL RUN AFTER RUN SENDS THE SIGNAL THAT
THE UPR RIDGE WILL BUILD OVR THE WESTERN GULF FRI THEN BECOME A
BLOCK OVR THE CENTRAL GULF FOR THE WHOLE WEEKEND. WE HAVE BEEN
DRENCHED AND IT IS ABOUT TIME FOR SOME DRY WEATHER EVEN IF THE
NIGHTTIME TEMPS WILL BE COOL. OUTLOOK INTO NEXT WEEK...BLOCK
HOLDS FOR DRY WEATHER HERE. MODELS USUALLY KICK OUT THE UPR RIDGE
TOO FAST AND DISCUSSED THAT WITH HPC. EXPECT A SPELL OF NICE
WEATHER INTO THE WEEK. WILL CHANGE P-GRIDS TO 12Z AK-GFS-40. A
NUDGE TO ECMWF LATER ON SUN FOR HIGHER PRESSURE IN THE YUKON AND
A TAD MORE WIND ESPECIALLY DUE TO 120-150KT NNW JET ALF WITH COLD
ADVECTION. WILL KNOCK A DEGREE OF TWO COOLER AT NIGHTTIME WHERE
NO WIND BUT OUR SOLAR DAY IS LONGER NOW.

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC...NONE
MARINE...SMCR PKZ012>013-022-033-036-041>043-051>052

FCF/JC