Small Craft Advisory 438, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
130 PM ADT FRI MAY 13 2007

.MODEL DISCUSSION...
MODELS ARE IN GOOD AGREEMENT WITH ALL MODELS FALLING IN LINE WITH THE
GFS SOLUTION. OTHERWISE THERE IS GOOD CONSISTENCY RUN TO RUN.

.ANALYSIS AND UPPER LEVELS...
WAA AT 850 MB WILL MOVE INTO SOUTHERN MAINLAND AK MON AS MORE
MOISTURE IS DRAWN IN ON SOUTHEAST FLOW ALOFT CIRCULATING AROUND A
BROAD LOW PRESSURE SYSTEM SOUTH OF KODIAK AND THE AK PENN. A SERIES
OF SHORTWAVES WILL MOVE AROUND THE LOW ACROSS SOUTHCENTRAL GENERATING
MORE SHOWERS AS THEY PASS THROUGH.

AT THE SURFACE A LOW SOUTH OF KODIAK IS ASSOCIATED WITH A BROAD FRONT
MOVING ACROSS THE SOUTHERN AND CENTRAL GULF. MAIN FORECAST PROBLEM
TONIGHT IS THE MOVEMENT OF THE FRONT AND TIMING. WITH THE LOW
DROPPING TO THE SOUTHWEST THE FRONT MAY DISSIPATE BEFORE THE EFFECTS
ARE REALLY FELT ACROSS SOUTHCENTRAL. HOWEVER IT COULD ALSO JUST SKIRT
THE SOUTHERN PART OF THE AREA. A RIDGE IS IN PLACE ALONG THE
SOUTHEAST COAST AND A LARGE RIDGE DOMINATES THE BERING.

.SHORT TERM FORECAST...

IN THE WEST...THE BERING RIDGE WILL KEEP MARINE STRATUS ACROSS THE
AREA WITH SOME RAIN AFFECTING THE WESTERN ALEUTIANS AS A WEAK FRONT
MOVES INTO THE AREA. THIS SHOULD PERSIST THROUGH TUE NIGHT. NORTHERLY
FLOW ACROSS THE EASTERN BERING AND ALEUTIANS WILL KEEP TEMPS COOL
ENOUGH FOR CONTINUED SNOW SHOWER ACTIVITY AND GUSTY WINDS.

SOUTH AND EAST OF THE AK RANGE...SOUTHEAST FLOW AROUND THE LOW WILL
KEEP PLENTY OF RAIN ALONG THE GULF COAST THROUGH MONDAY. MOST OF THIS
PRECIPITATION WILL BE DOWNSLOPED ON THE LEEWARD SIDE OF THE KENAI AND
CHUGACH MOUNTAINS...WITH SOME SURGES AS THE FRONT AND SUBSEQUENT
IMPULSES MOVE INLAND MONDAY AND TUESDAY. THIS STILL SHOULD YIELD
LITTLE MORE THAN SHOWERS NORTH OF THE CHUGACH.

OVER SOUTHWEST AK...THE LOW WELL SOUTH OF KODIAK WILL KEEP SOUTHEAST
FLOW STREAMING TOWARD THE AK AND ALEUTIAN RANGES THROUGH TUESDAY.
RADIATIONAL COOLING WILL CONTINUE TO KEEP TEMPS COOLER TONIGHT AND
MON MORNING BEFORE WARM AIR MOVES IN ALOFT. THIS WILL RESULT IN
CONTINUED SNOW SHOWERS ACROSS THE KUSKOKWIM VALLEY AND AK RANGE WITH
MINOR ACCUMULATIONS. TEMPS SHOULD WARM ENOUGH BY MON AFTERNOON TO
CHANGE PRECIP TO RAIN ACROSS THE REGION ALTHOUGH THERE IS THE
POTENTIAL FOR AREAS OF FREEZING RAIN DURING THE TRANSITION IN THE
MORNING. EXPECT RAIN SHOWERS TO CONTINUE ACROSS BRISTOL BAY THROUGH
TUE.

.LONG TERM FORECAST...
IN THE WEST THE RIDGE MOVES A BIT BUT REMAINS IN PLACE...WITH RAIN
OVER THE EXTREME WESTERN ALEUTIANS UNTIL NEXT WEEKEND. OVER SW AK
NEGATIVE VORTICITY ADVECTION WILL KEEP THE ATMOSPHERE STABLE
WED...WITH SOME CONVECTION DEVELOPING TOWARD THE END OF THE WEEK.
SOUTH AND EAST OF THE AK RANGE...THE TRANSITION OF THE LOW INTO THE
CENTRAL TO EASTERN GULF WILL KEEP NORTHEAST FLOW ACROSS THE
AREA...DRYING THINGS OUT BRIEFLY WED. THE DEVELOPMENT OF A THERMAL
TROUGH LATER WED WILL KEEP AFTERNOON AND EVENING CONVECTION OVER THE
COASTAL MOUNTAINS UNTIL THE END OF THE WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALES 120
FIRE WEATHER...NONE

RNW MAY 07