Small Craft Advisory 304, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
215 AM ADT FRI APR 8 2005

.DISCUSSION...

.ANALYSIS...TWO SURFACE LOW SOUTH OF DUTCH HARBOR AT THE MOMENT.
ONE AT 50N/164W WITH AN ESTIMATED PRESSURE OF 990 MB AND ANOTHER
AT 52.6N/166.6W WITH A PRESSURE OF 990 MB. THE SOUTHERN LOW IS THE
MORE IMPRESSIVE OF THE TWO AND HAS UPPER JET SUPPORT WHICH IS
STEERING IT OFF TO THE ENE. QUIKSCAT INDICATES 30 TO 35 KTS ON THE
SW TO SE SECTORS OF THE LOW. THE NORTHERN LOW...ALTHOUGH NOT AS
IMPRESSIVE...HAS A TIGHT PRESSURE GRADIENT AND COLD ADVECTION TO
ITS NORTH AND WEST. NORTHERLY WINDS OF 30 KT WITH HIGHER GUSTS CAN
BE FOUND ON THE BACK SIDE OF THE LOW (ACROSS THE EASTERN ALEUTIANS).
ALSO SOME SNOW RIGHT IN THE VICINITY OF THE LOW CENTER. ELSEWHERE
ACROSS THE BERING SEA REGION MAINLY COLD ADVECTION SNOW SHOWERS AND
NORTHERLY WINDS 20 TO 30 KTS. A WEAK FRONTAL BOUNDARY EXTENDS FROM
THE NORTHERN LOW EASTWARD ACROSS THE AKPENN AND SOUTH OF KODIAK
ISLAND INTO THE SOUTHERN GULF. THIS IS MOVING EVER SO SLOWLY
NORTHWARD. WEAK ISENTROPIC LIFT AND A FEW SMALL VORT-MAXES
PRODUCING SHOWERS ALONG THE NORTH GULF COAST.

.FORECAST...ETA/UKMET VERIFYING BEST WITH THE POSITION OF THE TWO
SURFACE LOWS. ETA IS TOO WEAK AS USUAL. TRACK OF SOUTHERN LOW INTO
GULF IS HANDLED SIMILARLY BY THE THREE MODELS THROUGH 48 HOURS
BEFORE DIVERGING TO SEPARATE SOLUTIONS. PREFER THE GFS TRACK (IT
HAS BEEN THE MOST CONSISTENT MODEL OF LATE). HOWEVER THINK THE
DEPTH OF THE LOW WILL BE SOMETHING MORE ALONG THE LINES OF THE
UKMET WHICH WEAKENS THE STORM OVER THE CENTRAL GULF AS UPPER JET
MOVES OFF TO THE SOUTH. FOR SOUTH CENTRAL...EXPECT SHOWERS TO
CONTINUE...MAINLY ALONG THE GULF COAST AS WEAK FRONT MOVES TO THE
COAST AND DISSIPATES THIS EVENING. OCCLUSION FROM LOW MOVING INTO
GULF WILL MOVE TO THE NORTH AND WEST OF THE LOW SATURDAY AND
DISSIPATE SATURDAY NIGHT. THIS WILL SERVE TO CONTINUE SHOWERS ALONG
THE COAST WITH AN OCCASIONAL SHOWER MAKING IT INLAND. THE LOW WILL
FINALLY MOVE OFF TO THE SOUTH MONDAY BRINGING A DRYING TREND TO
SOUTH CENTRAL. WITH LITTLE CHANGE IN THE PATTERN WILL CONTINUE TO
SEE HIGH TEMPS IN THE 40S AND LOWS IN THE 20S INLAND AND 30S ALONG
THE COAST.

OUT WEST...THE UPPER TROUGH AXIS WHICH EXTENDS FROM WEST OF THE
BERING STRAIT SOUTHWARD TO THE EASTERN ALEUTIANS WILL TRANSLATE
EASTWARD AND MODERATE COLD ADVECTION WILL PERSIST ACROSS THE BERING
REGION THROUGH SUNDAY. A RIDGE WILL BUILD OVER THE CENTRAL BERING
SUNDAY AS A CUT-OFF LOW MOVES TOWARD THE WESTERN ALEUTIANS. A WARM
FRONT WILL REACH WESTERN ALEUTIANS LATE SUNDAY WITH GALE FORCE WINDS
AND RAIN. SOUTHWEST ALASKA WILL REMAIN IN BETWEEN MOST OF THE MAIN
FEATURES AND THUS WILL REMAIN MOSTLY DRY WITH VARIABLE CLOUDS THROUGH
THE WEEKEND.

EXTENDED FORECAST...HEMISPHERIC PATTERN REMAINS IN LIMBO WITH
SEVERAL CUT-OFF LOWS WANDERING AROUND. THUS HAVE LOW CONFIDENCE
IN THE FORECASTS. WESTERN PACIFIC CUT-OFF PROGGED TO TRACK EASTWARD
TO NEAR KODIAK ISLAND BY THE END OF THE NEXT WEEK. SO AFTER A BRIEF
COOL DOWN OVER THE MAINLAND AT THE BEGINNING OF THE WEEK AND WARMING
OUT WEST MAY QUICKLY REVERSE BACK TO THE CURRENT SET UP OF WEAK
WARM ADVECTION OVER THE MAINLAND AND COLD ADVECTION OVER THE BERING.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALES AREA 12A. HEAVY FREEZING SPRAY WARNING AREAS 6A 15.

SEB APR 05