Small Craft Advisory 129, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
110 PM AKDT TUE SEP 23 2014

.DISCUSSION...

MODELS...GOOD AGREEMENT INTO THE EXTENDED PERIODS. THE SURFACE LOW
OVER THE ARCTIC COAST INITIALIZED A LITTLE FAR NORTH...BUT OVERALL
THEY INITIALIZED WELL. THERE WERE SOME PRETTY BIG DIFFERENCES IN
THE MODELS IN THE MID AND EXTENDED PERIODS IN PREVIOUS RUNS...BUT
THE LAST COUPLE RUNS SEEM TO HAVE RESOLVED THOSE ISSUES.

ALOFT...AT 500 HPA...A 521 DAM CLOSED LOW OVER THE ARCTIC PLAIN
WITH A SHORTWAVE EXTENDING SOUTH OVER MERRILL PASS WILL MOVE TO
74N 145W WITH THE SHORTWAVE EXTENDING SOUTH OVER BARTER ISLAND TO
DELTA JUNCTION TO PRINCE WILLIAM SOUND BY LATE THIS EVENING...THEN
CONTINUE EAST OUT OF THE STATE BY WEDNESDAY MORNING. A 541 DAM LOW
OVER THE SOUTHWEST BERING SEA WILL REMAIN QUASI STATIONARY THROUGH
WEDNESDAY AFTERNOON THEN MOVE EAST OVER THE ALEUTIAN CHAIN TO BE
OVER NIKOLSKI BY THURSDAY AFTERNOON...THEN 200NM SOUTHEAST OF SAND
POINT BY FRIDAY AFTERNOON...AND TO 200NM SOUTHWEST OF SITKA BY
SUNDAY MORNING. A RIDGE OVER THE EASTERN ALEUTIANS AND ALASKA
PENINSULA WILL BUILD NORTH THEN EAST BEHIND THE SHORTWAVE OVER THE
INTERIOR THEN SLOWLY MOVE EAST ACROSS THE STATE...EXITING THE
STATE SATURDAY MORNING. A RIDGE WILL BUILD NORTH OVER THE WESTERN
BERING SEA THURSDAY MORNING AND MOVE OVER THE WEST COAST BY
SATURDAY AFTERNOON. AT 850 HPA...ZERO ISOTHERM HAS REBOUNDED A
LITTLE TO LIE FROM EAGLE TO DELTA JUNCTION TO DENALI TO ANVIK TO
GAMBELL TODAY AND WILL SINK A LITTLE FURTHER SOUTH BEFORE
REBOUNDING TO LIE FROM EAGLE TO TANANA TO ANVIK TO THE BERING
STRAIT BY THURSDAY NIGHT...AND THEN FROM EAGLE TO POINT LAY BY
SATURDAY MORNING.

SURFACE...996MB LOW NORTHEAST OF BARROW WITH A COLD FRONT
STRETCHING TO DEADHORSE TO BETTLES TO ANVIK TO ST MATTHEW ISLAND
WILL CONTINUE NORTH WITH THE LOW NEAR 75N 140W EARLY WEDNESDAY
MORNING AND THE FRONT LYING FROM NORTHWEST TERRITORIES TO DAWSON
YUKON THEN WEST OVER THE SOUTH SLOPES OF THE ALASKA RANGE. HIGH
PRESSURE STRETCHES ACROSS THE SOUTHERN HALF OF THE MAINLAND AND
THE ALASKA PENINSULA. A HIGH OVER THE BERING STRAIT WILL REINFORCE
THE RIDGE AS IT MOVE TO THE INTERIOR TONIGHT BEHIND THE FRONT.
THE RIDGE WILL REMAIN OVER THE AREA THROUGH THURSDAY. A 1005MB LOW
IN THE WESTERN ALEUTIANS WILL MOVE TO 200NM SOUTH OF SAND POINT BY
FRIDAY NIGHT...THEN TO THE EASTERN GULF OF ALASKA BY SUNDAY
MORNING.

ARCTIC COAST AND PLAIN...WEATHER FRONT IS EAST OF BARROW AND WILL
CONTINUE TO THE EAST OUT OF THE AREA BY LATE THIS EVENING. CLOUDY
CONDITIONS WILL CONTINUE ACROSS THE AREA WITH SCATTERED SNOW
SHOWERS OR FLURRIES. WINDS SWITCH AROUND TO NORTHWEST AS THE FRONT
PASSES. WINDS WILL GENERALLY BE IN THE 10 TO 20 MPH HOURS RANGE
BECOMING LIGHT...BEFORE SWITCHING TO SOUTHWEST TO SOUTHEAST AS THE
NEXT LOW COME ACROSS THE CHUKCHI SEA TONIGHT TO BE OVER THE
NORTHWEST COAST EARLY WEDNESDAY MORNING. AS THIS LOW PASSES OVER
BARROW WEDNESDAY MORNING WINDS WILL SWITCH TO SOUTHWEST TO WEST
FOR MOST AREAS. THE SECOND LOW WILL PRODUCE ANOTHER ROUND OF SNOW
SHOWERS AND FLURRIES ACROSS THE AREA...BUT MAINLY OVER THE COASTAL
AREAS. GOES MVFR PROBABILITY 4KM PRODUCT AT 23/1845Z IS DISPLAYING
HIGH PROBABILITY OVER ALL OF THE COAST AND MOST OF THE COASTAL
PLAIN. SURVEY OF OBSERVATIONS CONFIRMS THE PRESENCE OF MAINLY
STRATUS CEILING AND SEE NO REASON FOR THEM TO GO AWAY.

WEST COAST AND WESTERN INTERIOR...MOST AREAS CLEARING OUT AS THE
FRONT MOVES SOUTH AND DISSIPATES WITH HIGH PRESSURE BUILDING BACK
IN OVER THE AREA BEHIND IT. A LITTLE REINFORCEMENT OF THE COLD
AIR AS THE HIGH BUILDS IN BUT NOTHING SIGNIFICANT. WEAK WARM AIR
ADVECTION OVER THE SOUTHWEST COAST BEGINNING THURSDAY AND
CONTINUING INTO THE WEEKEND. NO SIGNIFICANT WINDS EXPECTED UNDER
THE HIGH. PATCHY FOG ALONG THE RIVERS AND LAKES THE NEXT COUPLE OF
DAYS...BUT CLEARING DURING THE AFTERNOONS AND EVENINGS.

INTERIOR...FRONT WILL MOVE THROUGH THIS AFTERNOON AND EVENING.
MAINLY RAIN SHOWERS...BUT IT WILL MIX WITH SOME SNOW IN AREAS
ABOVE 1500 FEET. AREAS FROM THE ELLIOTT HIGHWAY NORTH WILL SEE A
MUCH BETTER CHANCE OF ACCUMULATING SNOW...BUT STILL NOT EXPECTING
IT TO AMOUNT TO MUCH WITH THE EXCEPTION OF THE AREAS NORTH OF THE
YUKON RIVER AND EAST OF THE DALTON HIGHWAY WHICH COULD SEE 4 TO 6
INCHES OF SNOW OVERNIGHT...ALSO WITH THE FRONT HANGING UP IN THE
EASTERN ALASKA RANGE THEY WILL SEE A COUPLE INCHES OF SNOW BEFORE
IT ENDS TOMORROW MORNING. WITH THE HIGH MOVING OVER THE AREA NOT
TOO MUCH WIND TO BE HAD SINCE THERE IS NOT MUCH COLD AIR
ADVECTION...SO LIGHT WINDS WILL PREVAIL.

&&

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...A RAPIDLY MOVING LOW WILL
MOVE TO THE NORTHWEST COAST BY LATE SUNDAY NIGHT. DEPENDING ON THE
STRENGTH OF THE LOW THIS MAY PRODUCE HIGH SURF ON THE NORTHWEST
COAST MONDAY INTO TUESDAY.

&&

.HYDROLOGY...AFTER A SLIGHT RISE IN THE RIVERS FROM THE RAIN THE
OTHER DAY THEY ARE NOW TRENDING DOWN AND WILL CONTINUE TO DO SO
INTO NEXT WEEK.

&&

.FIRE WEATHER...NONE.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

WINTER WEATHER ADVISORY FOR AKZ206-AKZ218.

SMALL CRAFT ADVISORY FOR PKZ220-PKZ225-PKZ230-PKZ235-PKZ240-
PKZ245.

GALE WARNING FOR PKZ245.

&&

SDB SEP 14