Small Craft Advisory 14, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
507 AM AKST TUE JAN 6 2015

.ANALYSIS AND UPPER LEVELS...
HIGH PRESSURE EXTENDING THROUGH THE NORTHERN BERING INTO THE
SOUTHERN BERING IS KEEPING DRY NORTHERLY FLOW OVER MUCH OF
MAINLAND ALASKA. LOW STRATUS AND FOG RESIDES UNDERNEATH THE
STABLE CONDITIONS. OVER SOUTHWEST ALASKA AN UPPER LEVEL LOW IS
SLIDING INTO THE EASTERN BERING AND OUT WEST A DISSIPATING FRONT
IS STALLING OUT OVER THE CENTRAL ALEUTIANS.

&&

.MODEL DISCUSSION...
THE BIGGEST CHALLENGE FOR THE MODELS TODAY IS WITH A NORTH PACIFIC
SYSTEM APPROACHING THE GULF WED EVENING. THERE IS A LARGE
VARIATION IN POSITIONING OF THIS LOW WITH THE NAM BEING BY FAR THE
SLOWEST. ALL OF THE MODELS EVENTUALLY BRING THE ENERGY INTO THE
EASTERN BERING AS THE UPPER LEVEL LOW OVER THE SOUTHWEST MOVES
OVER THE EASTERN BERING. THIS LOW IS HANDLED WITH DECENT
CONSISTENCY BETWEEN THE MODELS BUT MUCH DISCREPANCY REMAINS AROUND
THE GULF.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (TUESDAY AND WEDNESDAY)...
CONTINUED DRY WEATHER EXPECTED ACROSS SOUTH CENTRAL THROUGH
WEDNESDAY NIGHT AS HIGH PRESSURE REMAINS OVER THE AREA. THE
EXCEPTION IS KODIAK...WHERE A SERIES OF FRONTS ASSOCIATED WITH A
LOW OVER THE SOUTHERN GULF WILL SEND PULSES OF MOISTURE ACROSS THE
ISLAND. THERE IS A STRONG INVERSION OVER SOUTH CENTRAL WITH COLD
AIR TRAPPED AT THE SURFACE BY WARMER AIR ALOFT THAT IS ASSOCIATED
WITH THE RIDGE. THIS WILL KEEP SOME PATCHY FOG OVER SOME INLAND
AREAS. TEMPERATURES WILL REMAIN ROUGHLY THE SAME AS THEY HAVE BEEN
THROUGH WEDNESDAY...THEN BEGIN TO WARM WEDNESDAY NIGHT AS THE HIGH
PRESSURE WEAKENS AND MOVES NORTH...ALLOWING MORE CLOUDS INTO
SOUTHERN ALASKA.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (TUESDAY AND WEDNESDAY)...

MOISTURE ASSOCIATED WITH A SLOWLY DEVELOPING TRIPLE POINT WILL
BEGIN TO SPREAD FLURRIES AND LIGHT SNOW ACROSS THE AKPEN INTO
BRISTOL BAY TODAY...AND WITH MEASURABLE SNOWFALL WEST OF KING
SALMON WED NIGHT. THE LOWER KUSKOKWIM VALLEY WILL REMAIN DRY IN
THE DOWNSLOPE SHADOW OF THE ALASKA RANGE. GUSTY NORTHEAST WINDS
WILL AFFECT COASTAL AREAS THROUGH WED NIGHT.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (TUESDAY AND WEDNESDAY)...

THE DEVELOPMENT OF A TRIPLE POINT LOW IN THE EASTERN BERING WILL
BRING A CHANCE OF SNOW TO THE AKPEN AND EASTERN ALEUTIANS THROUGH
WED NIGHT. THE CENTRAL ALEUTIANS WILL BE GENERALLY DRY BENEATH A
RIDGE...WHILE THE NEXT SIGNIFICANT LOW WILL CROSS THE WESTERN
ALEUTIANS TODAY AND TONIGHT WITH SOME RAIN AND SNOW TODAY CHANGING
TO RAIN TONIGHT BEFORE ENDING ON WED.

&&

.LONG TERM FORECAST (THURSDAY THROUGH MONDAY)...
THERE REMAINS VERY GOOD MODEL AGREEMENT THAT A GULF LOW MOVING
INTO THE EASTERN BERING ON THURSDAY WILL BRING A RETURN TO THE
WARM AND MOIST SOUTHEASTERLY FLOW OVER THE GULF THAT WILL
CONTINUE INTO THIS WEEKEND. THIS WILL BRING STEADY RAIN FROM
KODIAK ISLAND INTO THE WESTERN GULF COAST...WITH RAIN AND SNOW
FALLING OVER THE SOUTHWEST MAINLAND. FOR INTERIOR LOCATIONS OF
SOUTHCENTRAL...ITS LOOKING MORE AND MORE LIKELY THAT DOWNSLOPING
WILL LIMIT PRECIPITATION CHANCES TO JUST A FEW PASSING RAIN AND
SNOW SHOWERS AS TEMPERATURES RETURN TO ABOVE NORMAL UNDER
SOUTHEASTERLY FLOW.

AFTER THIS SYSTEM DISSIPATES EARLY THIS WEEKEND...UNCERTAINTY
CONTINUES FURTHER OUT IN THE FORECAST BUT CONTINUES TO REVOLVE
AROUND THE SAME FEATURES AND THEIR POSITION RELATIVE TO EACH
OTHER. THERE IS GOOD AGREEMENT THAT ANOTHER NOPAC LOW WITH DEEP
SOUTHERLY FLOW WILL APPROACH THE GULF EARLY NEXT WEEK...WHICH WILL
LIKELY BRING A PROLONGED PERIOD OF ABOVE NORMAL TEMPERATURES AND
ACTIVE WEATHER TO MUCH OF THE SOUTHERN MAINLAND INTO NEXT WEEK.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 127 130 138 178 181 185.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...DK
SOUTHCENTRAL ALASKA...BL
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...DS
LONG TERM...DEK