Small Craft Advisory 51, NWS Anchorage, AK

AREA FORECAST DISCUSSION SOUTHWEST ALASKA
1200 PM AST FRI JAN 14 2005

.DISCUSSION...

ETA INITIALIZED BEST WITH THE HIGH PRESSURE CENTER OVER YUKON
TERRITORY KEEPING IT STRONGER THAN OTHER MODELS AND HAVING A BETTER
HANDLE ON THE PRESSURE FIELD OVER THE COPPER RIVER BASIN AND NORTH
GULF COAST. MODELS ARE IN PRETTY CLOSE AGREEMENT ON LARGE COMPLEX
NORTH PACIFIC LOW UNTIL ABOUT 48 HOURS. AFTER THAT GFS KEEPS PACIFIC
LOW MUCH DEEPER THAN ETA AND DEVELOPS A LARGE LOW SOUTH OF THE
PANHANDLE AT 72 HOURS. THIS CONFLICT WITH THE ETA OUTPUT AT THE SAME
TIME WHICH PLACES THE LOW SOUTH OF KODIAK WITH A DEEPER PRESSURE.
THEREFORE WOULD RECOMMEND GOING WITH ETA THROUGH 48 HOURS AND THEN GO
WITH GFS (OR UKMET/ECMWF) WHICH HANDLES THE PACIFIC LOW BETTER.

UPPER RIDGE ACROSS EASTERN RUSSIA..SOUTHWEST ALASKA..AND NORTHEAST
PACIFIC WEAKENS THROUGH THE PERIOD AS UPPER LOW IN NORTH PACIFIC AND
DIGGING UPPER LOW OVER NORTHERN ALASKA BREAKS DOWN RIDGE OVER
SOUTHWEST ALASKA. MOISTURE WRAPPING AROUND UPPER RIDGE BRINGING SNOW
TO SOUTHERN ALASKA THIS MORNING WILL CONTINUE TO EFFECT THE SOUTHERN
MAINLAND THROUGH THE PERIOD AS UPPER TROUGH FROM NORTH ADDS LIFT TO
MOIST AIR. THIS..COUPLED WITH PERSISTENT EASTERLY FLOW OVER GULF OF
ALASKA AND NORTH PACIFIC..WILL KEEP CLOUDS AND PRECIPITATION OVER THE
AOR THROUGH THE PERIOD. WINDS WILL BE SMALL CRAFT TO GALE OVER MOST
MARINE ZONES OVER THE AOR.

TERMINALS CONTINUE TO REFLECT DIRECTIONAL SHEAR OVER THE SOUTHWEST AS
SURFACE WINDS ARE LIGHT AND VARIABLE PRIMARILY FROM THE NORTHEAST AND
THE WINDS AT 2000 FEET ARE FROM THE SOUTHEAST AROUND 25 KNOTS. WILL
KEEP THE SHEAR IN THE TERMINALS UNTIL THE UPPER WINDS BECOME MORE IN
LINE (NO DIRECTIONAL WITH STEADY INCREASE WITH HEIGHT) WITH SURFACE
WINDS AFTER MIDNIGHT.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALES 3A 3C 4 AND ALL WESTERN ZONES.
FIRE WEATHER...NONE.

JWP JAN 05