Small Craft Advisory 61, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AKST FRI JAN 16 2009

.MODEL DISCUSSION...
MODELS ARE CONSISTENT IN HANDLING THE OVERALL PATTERN AND MAJOR
FEATURES THROUGH SATURDAY. DISCREPANCIES BEGIN TO ARISE SUNDAY
CONCERNING THE LOW MOVING FROM THE NORTH PACIFIC INTO THE GULF OF
ALASKA...AS WELL AS HANDLING THE EVOLUTION OF MULTIPLE LOW CENTERS IN
THE NORTH PACIFIC AND BERING SEA. THE GFS WAS THE PREFERRED MODEL
THIS MORNING DUE TO CONTINUED SHORT TERM CONSISTENCY. REGARDING THE
LOW EXPECTED TO MOVE INTO THE GULF ON SUNDAY...THE 00Z ECMWF AND GFS
HAVE COME INTO BETTER AGREEMENT WITH A SINGLE LOW CENTER. THE GFS/NAM
SOLUTION IS SLOWER AND WEAKER THAN THE ECMWF...ALTHOUGH THE ECMWF
CONTINUES TO TREND TOWARD A SLOWER SOLUTION.

.ANALYSIS AND UPPER LEVELS...
AN UPPER LEVEL LOW WAS LOCATED OVER NORTHEASTERN RUSSIA WITH A TROUGH
EXTENDING THROUGH THE CENTRAL AND EASTERN ALEUTIANS. A SECONDARY
UPPER LOW IS FORMING ON THE BASE OF THIS TROUGH THIS MORNING SOUTH OF
THE ALASKA PENINSULA.  THE MAIN JET CORE IS WELL SOUTH OF
ALASKA...EXTENDING ACROSS THE PACIFIC BETWEEN 30N AND 40N. MULTIPLE
JET STREAKS ARE ROUNDING THE BASE OF THE TROUGH AND MOVING NORTHWARD
OVER MAINLAND ALASKA.

AT THE SURFACE...STRONG SOUTHERLY FLOW CONTINUES TO EXTEND FROM THE
NORTH PACIFIC THROUGH MAINLAND ALASKA. ELSEWHERE A 955 MB LOW 150 NM
SOUTH OF SAND POINT IS MOVING NORTHWARD. THE SURFACE LOW IS BEING
FUELED IN PART BY FAVORABLE SUPERPOSITION BETWEEN THE AFOREMENTIONED
JET STREAKS.  THE SURFACE PRESSURE GRADIENT IS STRENGTHENING ONCE
AGAIN THIS MORNING ACROSS MAINLAND ALASKA AS THE SURFACE LOW
CONTINUES TO MOVE NORTHWARD.

.SHORT TERM FORECAST...
.SOUTHCENTRAL...
AS THE LOW SOUTH OF SAND POINT CONTINUES TO TRACK NORTHWARD EXPECT
WINDS TO REMAIN STRONG AND GUSTY INTO TONIGHT.  WINDS THROUGH
CHANNELED AND HIGHER TERRAIN WILL BE COMPARABLE TO OR PERHAPS
STRONGER THAN THOSE EXPERIENCED WEDNESDAY NIGHT (EXCEEDING 100 MPH).
ANOTHER ROUND OF HEAVY RAIN WILL AGAIN IMPACT LOCATIONS ALONG THE
GULF COAST THROUGH TONIGHT...WITH LIGHTER AMOUNTS FOR INLAND AREAS.

.SOUTHWEST...
AS THE LOW MOVES INTO SOUTHWEST ALASKA THIS MORNING STRONG WINDS AND
RAIN WILL BECOME WIDESPREAD. AS THE LOW DEPARTS TO THE NORTH AND COLD
AIR WRAPS AROUND THE SYSTEM LATER TODAY...PRECIPITATION WILL BEGIN TO
MIX WITH OR CHANGE TO SNOW.  BY TONIGHT PRECIPITATION WILL BECOME ALL
SNOW ACROSS SOUTHWEST ALASKA...WITH LIGHT ACCUMULATIONS EXPECTED.
CONDITIONS WILL BE IMPROVING OVER THE WEEKEND...WITH LIGHTER WINDS
AND SCATTERED SNOW SHOWERS PERSISTING ACROSS THE SOUTHWEST MAINLAND.

.BERING SEA/ALEUTIANS...
STRONG NORTHERLY FLOW WILL BEGIN WEAKENING THIS AFTERNOON AS THE LOW
CENTER IMPACTING THE AK PENINSULA LIFTS NORTHWARD. BLIZZARD
CONDITIONS IN THE PRIBILOFS WILL CONTINUE THROUGH THIS
AFTERNOON...AFTER WHICH WINDS AND SNOW WILL BEGIN TO ABATE. A SERIES
OF WEAK SURFACE DISTURBANCES WILL BEGIN TO MOVE OVER THE WESTERN
ALEUTIANS AND BERING SEA THROUGH THE WEEKEND...BUT MODERATE WINDS AND
SCATTERED SNOW SHOWERS WILL BE THE RULE.

.LONG TERM FORECAST...
THE STRONG RIDGE OVER THE ALASKA MAINLAND WILL MOVE EASTWARD INTO
SOUTHEAST ALASKA AND WESTERN CANADA BY EARLY WEEK...SHIFTING THE CORE
OF SOUTHERLY FLOW TO THE EAST AS WELL. COLDER AIR WILL BEGIN
SPREADING BACK INTO MAINLAND ALASKA FROM THE BERING...RESULTING IN
MORE SEASONABLE WEATHER ACROSS SOUTHERN ALASKA AS WE MOVE INTO NEXT
WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 195
         HIGH WIND WARNING 101 125 135 161 171
MARINE...STORM WARNING 120 130 132 138 150 351 352
         GALE WARNING 121 125 129 140 141 155 160 165 170 171 172 179
                      180 185 412 413 414
         HEAVY FREEZING SPRAY WARNING 179 412 414
FIRE WEATHER...NONE

NRH/JCA JAN 09