Small Craft Advisory 627, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM ADT FRI AUG 3 2007

.MODEL DISCUSSION...
NAM HAS NOT INITIALIZED THE VORT MAXES THROUGHOUT THE BERING ALL THAT
WELL THIS MORNING. GFS AND UKMET HAD A GOOD HANDLE ON THESE FEATURES.
THE OVERALL PATTERN IS ONCE AGAIN HANDLED WELL BY ALL MODELS THROUGH
THURSDAY THEN THE SOLUTION STARTS TO DIVERGE. AT THE SURFACE...ECMWF
AND GFS MATCH UP THE BEST WITH MINOR DIFFERENCES WITH THE UKMET. ALL
THESE ARE DUE TO VARIANCES OF THE SEPARATE VORT MAXES. GOING AHEAD
WITH A GFS/ECMWF FORECAST SOLUTION. IN ADDITION...THE RUN TO RUN
CONSISTENCY WITH THE GFS IS GOOD.

.ANALYSIS AND UPPER LEVELS...
HIGH PRESSURE OVER THE EASTERN AND NORTHEAST GULF COAST THIS
AFTERNOON. THIS IS CREATING SOME STRONGER WINDS TRHOUGH TURNAGAIN
ARM. BROAD SOUTHWEST FLOW OVER SOUTHWEST ALASKA AND INTO SOUTH
CENTRAL AS WELL. A FRONT IS OVER THE EASTERN BERING STRETCHING TO THE
WESTERN GULF. THE FRONT WILL MOVE ONSHORE TONIGHT IN WESTERN ALASKA
AND TO SOUTH CENTRAL AS WELL. THE FAST MOVEMENT OF THE FRONT IS DUE
TO A STRONG SOUTHWEST FLOW AT ALL LEVELS. IN ADDITION...A LOW IS
DEVELOPING SOUTH OF ADAK AND WILL MOVE TO THE CENTRAL ALEUTIANS
TONIGHT.

A BROAD UPPER LEVEL LOW OVER THE BERING WITH A STRONG JET ORIENTED
FROM THE NORTHERN PACIFIC THROUGH BRISTOL BAY TO THE MAINLAND. THIS
IS PROVIDING LIFT ALONG THIS BAND FOR SHOWERS AND AREAS OF RAIN
THROUGH THE ALEUTIANS AND INTO THE MAINLAND. A SURFACE LOW WILL
DEVELOP ALONG THIS JET MAX TONIGHT SOUTH OF ADAK. THE UPPER LEVEL LOW
HAS MANY VORT MAXES ROTATING AROUND IT. THE STRONG JET ROUNDING THE
BASE OF THE LOW IN ADDITION TO A LOW DROPPING TO THE KAMCHATKA
PENINSULA WILL HELP THE LOW IN THE BERING LIFT EAST AND NORTH
SATURDAY. AS THE LOW OVER THE KAMCHATKA DEEPENS AND EXTENDS A RIDGE
INTO THE WESTERN BERING SUNDAY...THE BERING LOW LIFTS TO THE
MAINLAND. IN ADDITION...THIS WILL PUSH THE RIDGE IN THE GULF TO THE
PANHANDLE SUNDAY NIGHT. THE KAMCHATKA LOW SLOWLY MOVES INTO THE
BERING MONDAY THROUGH WEDNESDAY WITH A RIDGE BEING ESTABLISHED OVER
THE EASTERN BERING AND WESTERN ALASKA. THIS WILL LEAVE TROUGH OVER
EASTERN ALASKA...THE YUKON AND PANHANDLE. THE NEW BERING LOW WILL
SHIFT FURTHER EAST THROUGH FRIDAY WITH THE RIDGE MOVING OVER THE
MAINLAND AND OPEN WESTERN ALASKA TO THE MOIST SOUTHWEST FLOW AGAIN.

.SHORT TERM FORECAST...
SOUTH CENTRAL.
FRONT ROTATING NORTHEAST TONIGHT ALONG THE JET AT THE BASE AND FRONT
OF THE LARGE UPPER LOW IN THE BERING. SOME WINDS ALONG THE FRONT FOR
SMALL CRAFT ADVISORIES. A RIDGE OF PRESSURE ALONG THE NORTHERN COAST
COMBINED WITH A LIGHT SOUTHEAST FLOW AT MID LEVELS...CREATING SOME
MODERATE GAP WINDS. THESE WILL LAST THROUGH SUNDAY. THE FRONT WILL
WORK NORTH THROUGH KODIAK AND THE KENAI PENINSULA THIS EVENING AND
INLAND OVERNIGHT. THE FRONT WEAKENS A BIT SATURDAY MORNING...BUT IS
QUICKLY REINFORCED BY A JET MAX PUSHING OVER SOUTH CENTRAL SATURDAY
AFTERNOON. A LOW IN BRISTOL BAY WILL MOVE INLAND SUNDAY MORNING WITH
A STRONG JET FROM NEAR DUTCH HARBOR THROUGH CENTRAL ALASKA. THIS FLOW
WILL BE FEEDING WARM MOIST AIR TO SOUTH CENTRAL WITH PLENTY OF
PRECIPITATION THROUGH SUNDAY EVENING. THE JET WILL THEN MOVE OFF TO
THE EAST MONDAY...BUT THEN THE TROUGH SETTLES OVER SOUTH CENTRAL WITH
CONTINUED SHOWER ACTIVITY.

SOUTHWESTERN ALASKA.
FRONT MOVING ONSHORE THIS AFTERNOON WITH MODERATE JET SUPPORT AND
WARMER AIR TO THE SOUTH. SOME WINDS ALONG THE FRONT FOR SMALL CRAFT
ADVISORIES. PRECIP TO SPREAD INLAND TONIGHT. THERE WILL BE A SLIGHT
BREAK SATURDAY MORNING BEFORE A STRONG SOUTHWEST FLOW WITH A STRONG
JET ARRIVES EARLY SATURDAY AFTERNOON. THIS WILL BRING ANOTHER ROUND
OF MODERATE TO HEAVY PRECIPITATION. A LOW WILL ALSO MOVE TO BRISTOL
BAY SATURDAY NIGHT AND MOVE INLAND SUNDAY. MODERATE WINDS ALSO
ASSOCIATED WITH THIS LOW SATURDAY NIGHT ALONG THE COAST. HIGH
PRESSURE TO MOVE INTO SOUTHWEST ALASKA LATE MONDAY.
THEREFORE...SHOWERS TO LAST THROUGH MONDAY.

BERING/ALEUTIANS.
BROAD UPPER LEVEL LOW WITH AREAS OF SHOWERS AND FOG OVER THE BERING.
LIGHT WINDS OVER MUCH OF THE BERING. EXPECT WINDS TO PICK UP AS A LOW
MOVES TO THE CENTRAL ALEUTIANS LATER TONIGHT. WINDS WILL BE GALE
FORCE TOMORROW AS THE LOW CROSSES THE CENTRAL ALEUTIANS AND MOVES TO
NUNIVAK ISLAND SATURDAY NIGHT. MODERATE TO HEAVY PRECIPITATION TO BE
ASSOCIATED WITH THIS LOW AS IT HAS GREAT UPPER LEVEL SUPPORT. THE
PRECIP WILL SPREAD FROM THE CENTRAL ALEUTIANS ACROSS THE AKPEN
THROUGHOUT THE EASTERN BERING. GOOD WESTERLY WINDS BEHIND THE LOW
INTO SUNDAY MORNING BEFORE THE LOW MOVES INLAND. HIGH PRESSURE MOVES
OVER THE WESTERN BERING AT THIS TIME AS WELL. BY SUNDAY
AFTERNOON...HIGH PRESSURE WILL MOVE OVER THE CENTRAL BERING WITH A
STRONG FRONT MOVING NEAR SHEMYA AND SHOWERS ASSOCIATED WITH THE UPPER
TROUGH OVER THE EASTERN BERING. THE RIDGE WILL PUSH OVER THE EASTERN
BERING MONDAY WITH THE FRONT SLOWLY MOVING TOWARD ADAK BY MONDAY
AFTERNOON. GALE FORCE WINDS WILL ACCOMPANY THIS FRONT AS IT IS A DEEP
LOW JUST EAST OF THE KAMCHATKA PENINSULA.

.LONG TERM FORECAST...
THE TROUGH OVER THE MAINLAND ON MONDAY TO PUSH OUT OF THE AREA
TUESDAY NIGHT AND REPLACED BY THE BERING HIGH PRESSURE THROUGH
THURSDAY. THEREFORE...SHOWERS WILL PREVAIL OVER SOUTH CENTRAL MONDAY
AND TUESDAY. MOIST SOUTHWEST FLOW TO RETURN TO SOUTH CENTRAL FRIDAY.

THE RIDGE WILL REMAIN OVER SOUTHWEST ALASKA THROUGH MUCH OF
WEDNESDAY. MOIST SOUTHWEST FLOW WILL RETURN LATE WEDNESDAY AFTERNOON
WITH A FRONT PUSHING INLAND THURSDAY. THE FLOW WILL REMAIN THROUGH
FRIDAY.

THE LOW NEAR KAMCHATKA MONDAY TO SLOWLY MOVE INTO THE BERING THROUGH
NEXT WEEK. A BROAD AREA OF LOW PRESSURE WILL RETURN TO THE BERING BY
THURSDAY NIGHT. THE ASSOCIATED FRONT FROM THIS LOW WILL MOVE FROM THE
WESTERN BERING MONDAY TO THE WEST COAST OF ALASKA WEDNESDAY EVENING.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE 170
FIRE WEATHER...NONE

JN AUG 07