Small Craft Advisory 93, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
345 AM AKDT SUN SEP 4 2011

.DISCUSSION...

MODELS...REMAIN IN VERY GOOD AGREEMENT IN THE SHORT TERM.
SIGNIFICANT DIFFERENCES DO NOT REALLY SHOW UP UNTIL LATE FRIDAY.

ALOFT...500 MB LOW IN THE GULF CONTINUES TO DRIFT EAST. LOW HAS
MOVED FROM THE CHUKOTSK PENINSULA TO NEAR NUNIVAK ISLAND AND
IS STRENGTHENING...THE LOW WILL MOVE SOUTH ACROSS THE ALASKA
PENINSULA TONIGHT THEN MOVE NORTHEAST TO KODIAK ISLAND BY MONDAY
EVENING. WEAK RIDGE OVER THE SOUTHEAST INTERIOR AND ACROSS THE
NORTHERN HALF OF THE STATE. RIDGE WILL REMAIN OVER THE BROOKS
RANGE AND ARCTIC COAST INTO MID WEEK.

SURFACE...992 MB LOW NEAR NUNIVAK ISLAND WILL DRIFT SOUTH AND
COMBINE WITH LOW DEVELOPING THE IN THE WESTERN BERING SEA TO BE
A 974 LOW 200 NM SOUTH OF COLD BAY TONIGHT. THE LOW WILL THEN
CONTINUE TO 100 NM SOUTHEAST OF KODIAK AS A 959 MB LOW MONDAY
NIGHT. STRONG GRADIENT WILL DEVELOP AROUND THE LOW WHICH WILL
BRING STRONG NORTH WINDS TO THE WEST COAST MONDAY THROUGH
WEDNESDAY. WEAK HIGH PRESSURE WILL REMAIN OVER THE ARCTIC COAST
INTO MID WEEK.

ARCTIC COAST...COLD AIR WILL DROP OUT OF THE ARCTIC...SOUTH TO
THE BROOKS RANGE TUESDAY BRINGING BELOW NORMAL TEMPERATURES TO
THE AREA. WITH THE COLD AIR MOVING IN MIDWEEK THERE COULD BE
SOME SNOW SHOWERS IN THE BROOKS RANGE. OTHERWISE THE SHORT TERM
CHALLENGE AGAIN WILL BE STRATUS AND FOG MOVING AROUND THE COASTAL
AREAS. WINDS WILL REMAIN RELATIVELY LIGHT INTO MID WEEK.

WEST COAST...NORTH WINDS 20 TO 25 MPH DEVELOPING TONIGHT THEN
INCREASING TO 25 TO 50 MPH FOR MANY COASTAL AREAS ON MONDAY.
THIS SHOULD BRING HIGHER THAN NORMAL SURF TO NORTH FACING EXPOSED
AREAS BEGINNING AS EARLY AS MONDAY AFTERNOON. PRECIPITATION WILL
BE SPOTTY EXCEPT FOR ST LAWRENCE ISLAND WHICH SHOULD SEE PERIODS
OF RAIN FOR THE NEXT COUPLE DAYS.

INTERIOR...EXPECT A FEW SPRINKLES OR LIGHT SHOWERS TODAY WITH
MOSTLY CLOUDY CONDITIONS AS REMNANTS OF THE SYSTEM THAT MOVED
THROUGH SATURDAY CONTINUE TO SCATTER UNDER THE BROAD LOW
PRESSURE PATTERN OVER THE AREA.

MID RANGE...THE MODELS REMAIN TIGHTLY CLUSTERED AT THE START OF
THE MEDIUM RANGE. A VERY DEEP LOW (960 MB) FOR EARLY SEP IN THE
VICINITY OF KODIAK ISLAND WILL BEGIN TO RAPIDLY FILL TUE NIGHT
INTO WED. TROUGHING EXTENDING INTO THE INTERIOR WILL CAUSE A
SECONDARY MACKENZIE BAY LOW TO DEVELOP TUE NIGHT THAT WILL THEN
MOVE EAST INTO CANADA. AN UPPER LOW OFF THE ARCTIC COAST WILL
THEN PHASE WITH THE UPPER LOW IN THE GULF TO FORM AN EXTENSIVE
TROUGH ALONG 160W. BY LATE IN THE WEEK INTO NEXT WEEKEND THE
MODEL SPREAD INCREASES SIGNIFICANTLY AND THE RELATIVE MEASURES OF
PREDICTABILITY FALL RAPIDLY. MUCH OF THIS UNCERTAINTY IS CAUSED
BY THE REMAINS OF EX-TROPICAL STORM TALAS WHICH IS MOVING THROUGH
THE SEA OF JAPAN AND IS EXPECTED TO MOVE NORTH/NORTHEAST INTO
RUSSIA LATER THIS WEEK. THIS MAKES THE DOWNSTREAM PATTERN ACROSS
ALASKA HIGHLY UNCERTAIN. THE ECMWF MAINTAINS A TROUGH ACROSS THE
MAINLAND AS MOST OF THE UPSTREAM ENERGY REMAINS ACROSS RUSSIA.
THE GFS IS MORE PROGRESSIVE IN MOVING THE ENERGY OFF INTO THE
CHUKCHI SEA AND DEVELOPS A STRONG RIDGE ACROSS EASTERN ALASKA
BY NEXT WEEKEND. CB.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...SEE COASTAL HAZARD MESSAGE
(WHAK49 PAFG).

&&

.FIRE WEATHER...A FEW WIDESPREAD LIGHTNING STRIKES ARE POSSIBLE
AGAIN TODAY.

&&

.HYDROLOGY...NONE.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY FOR PKZ210-PKZ220-PKZ225.
&&

SDB SEP 11