Area Forecast Discussion
Issued by NWS Fairbanks, AK

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FXAK69 PAFG 212050
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
1250 PM AKDT SUN SEP 21 2014

.DISCUSSION...

MODELS...INITIALIZED WELL. GOOD CONTINUITY OVER THE SHORT TERM
RUN TO RUN. MODELS APPEAR TO BE DOING A LITTLE BETTER THIS RUN IN
THE MID RANGE BEFORE THEY START DIVERGING. WILL JUST NUDGE THE
CURRENT FORECAST GRID TO A MODEL BLEND SINCE THEY HAVE SIMILAR
SOLUTIONS IN THE SHORT TERM...AND WORK WITH WPC GUIDANCE FOR THE
EXTENDED PERIODS.

ALOFT...AT 500 HPA...A 531 DAM CLOSED LOW OVER THE ARCTIC PLAIN
WITH A SHORTWAVE EXTENDING SOUTH OVER DENALI TO WESTERN COOK
INLET TO 537 DAM LOW OVER THE SOUTHCENTRAL GULF OF ALASKA. THE LOW
OVER THE PLAINS WILL DISSIPATE AS IT MOVES NORTH AND IS ABSORBED
BY A 522 DAM LOW OVER WRANGEL ISLAND. THE TROUGH OVER THE INTERIOR
WILL MOVE TO LIE FROM OVER KUPARUK TO FAIRBANKS TO 534 DAM LOW
OVER NORTHEAST GULF OF ALASKA. THE TROUGH WILL CONTINUE TO MOVE
EAST TO LIE FROM BARTER ISLAND TO DELTA JUNCTION TO OVER THE
CENTRAL GULF OF ALASKA BY MONDAY MORNING...THEN SLIDE EAST OUT OF
THE STATE BY TUESDAY MORNING. A 524 DAM CLOSED LOW WILL CONTINUE
TO MOVE RAPIDLY EAST TO BE OVER THE NORTHWEST COAST BY MONDAY
AFTERNOON AT 519 DAM...THEN CONTINUES EAST TO BE 200 NM NORTH OF
DEADHORSE BY TUESDAY AFTERNOON. SHORTWAVE ASSOCIATED WITH THE LOW
WILL LIE OVER THE BERING STRAIT BY MONDAY MORNING...THEN FROM
BARROW TO BETHEL BY TUESDAY MORNING...AND EXIT INTO CANADA BY
WEDNESDAY MORNING. AT 850 HPA...ZERO ISOTHERM LIES FROM MACKENZIE
BAY TO FORT YUKON TO DOT LAKE THEN SOUTHWEST...IT WILL CONTINUE TO
MOVE EAST AND SOUTH TONIGHT AND THEN REMAIN SOUTH OF THE FORECAST
AREA THROUGH THE WEEK EVEN AS THE TEMPERATURES REBOUND A LITTLE
OVER THE SOUTHWEST COAST.

SURFACE...A BROAD AREA OF LOW PRESSURE OVER THE EASTERN INTERIOR
WILL CONTINUE TO MOVE EAST. A 1002MB LOW NEAR CAPE HALKETT WILL
MOVE SLOWLY NORTHEAST THEN BE ABSORBED BY LOW THAT IS MOVING OUT
OF SIBERIA TO CAPE LISBURNE BY MONDAY MORNING AS A 995MB LOW. THE
LOW THEN MOVES FROM CAPE LISBURNE TO NEAR BARROW BY MONDAY NIGHT
AT 993MB...CONTINUING TO 250NM NORTH OF BARTER ISLAND BY EARLY
WEDNESDAY. THE ASSOCIATED FRONT WILL LIE FROM CAPE LISBURNE THROUGH
THE BERING STRAIT TONIGHT...THEN FROM WAINWRIGHT TO AMBLER TO NOME
BY MONDAY AFTERNOON...AND FROM BARTER ISLAND TO TANANA TO CAPE
ROMANZOF BY TUESDAY MORNING...AND FROM MACKENZIE BAY TO DELTA
JUNCTION THEN WEST ALONG THE ALASKA RANGE BY WEDNESDAY NIGHT AS IT
WEAKENS AND DISSIPATES. A 1002MB LOW NEAR 72N 160W WILL MOVE TO
THE NORTHWEST COAST BY WEDNESDAY MORNING.

ARCTIC COAST AND PLAIN...CONTINUES TO BE A LOT GOING ON AS SYSTEMS
MOVE QUICKLY THROUGH THE AREA DURING THIS TRANSITION SEASON. THE
OPEN WATER IS CREATING ALL SORTS OF ISSUE WITH DETERMINATION OF
PRECIPITATION TYPE...ESPECIALLY IN THE COASTAL AREAS. THE MESSY
MIX OF LOW CLOUDS...FOG...SNOW ...RAIN...WIND...AND COOLING
TEMPERATURES CONTINUES WITH NO END IN SIGHT AT THIS TIME.
SATELLITE PRETTY MUCH TELLS IT ALL WHEN YOU LOOK AT THE GOES MVFR
PROBABILITY 4KM AT 21/1900Z IT CONTINUES TO SHOW HIGH PROBABILITY
OF MVFR OVER VAST AREAS OF THE STATE AND OFFSHORE AREAS.
OBSERVATIONS ACROSS THE ARE CONFIRM THE LOW STRATUS AND SOME AREAS
ARE REPORTING PATCHY FOG. NOT EXPECTING ANY CHANGES AS THE LOW IN
SIBERIA MOVES ACROSS THE AREA...AND YET ANOTHER LOW MOVES TO THE
AREA BY WEDNESDAY.

WEST COAST AND WESTERN INTERIOR...HIGH PRESSURE OVER THE WEST
COAST WILL BE PUSHED SOUTH A LITTLE AS LOW IN SIBERIA MOVES OVER
THE TOP OF IT. WILL PROVIDE FOR A VARIETY OF WEATHER ACROSS THE
AREA. NPP VIIRS 11.45 UM BT PRODUCT AT 21/1641Z SHOWING SOME AREAS
OF MID AND LOW CLOUDS IN THE COASTAL AREAS WITH PREDOMINANTLY
CLEAR SKIES OVER THE INTERIOR AREAS. AS THE LOW WORKS ACROSS THE
TOP OF THE RIDGE IT WILL SPREAD CLOUDY CONDITIONS AND SOME
RAINFALL AS FAR SOUTH AS NORTON SOUND BY TOMORROW THEN INLAND
AREAS AS THE FRONT PUSHES SOUTHEAST. THE FRONT WILL WEAKEN AS IT
PROGRESSES EAST AND SOUTH WITH ONLY LIGHTER AMOUNTS OF
PRECIPITATION EXPECTED. NOT A BIG WINDS EVENT FOR MOST AREAS...BUT
IT COULD BE A LITTLE BREEZY IN THE KOTZEBUE SOUND AREA AS THE LOW
MOVES JUST NORTH OF THERE.

INTERIOR...CLEARING FROM FAIRBANKS WEST TONIGHT AS THE UPPER LEVEL
TROUGH MOVES THROUGH THE AREA. STILL GOING TO GET SOME RAIN OVER
THE SOUTHEAST INTERIOR AND FORTYMILE COUNTRY AS LOW IN THE GULF
SPINS SOME MOISTURE INTO THAT AREA. RAINFALL AMOUNTS IN THE
FORTYMILE AND UPPER TANANA RIVER BASIN WILL BE IN THE ONE QUARTER
TO ONE HALF INCH RANGE. EXPECT SOME SNOW AT THE HIGHEST ELEVATIONS
OF THOSE AREAS AS THE COLD AIR CONTINUES TO SINK SOUTH OVER THE
AREA BUT NO SIGNIFICANT ACCUMULATION THIS TIME AROUND. 850 HPA
TEMPERATURE AT FAIRBANKS WAS APPROACHING ZERO CELSIUS ON THE 12Z
UPPER AIR RUN AND SHOULD BE AROUND 2 BELOW CELSIUS THIS AFTERNOON.
PATCHY FOG...ESPECIALLY NEAR THE RIVERS AND LAKES TONIGHT AS
CLEARING OCCURS AND COOLER AIR MOVES INTO THE AREA. NOT TO BE LEFT
OUT THE ALASKA RANGE IS GETTING A NEW COAT OF SNOW BUT IT WILL NOT
AMOUNT TO MUCH. TEMPERATURES IN THE WESTERN INTERIOR TONIGHT WILL
FALL RATHER SHARPLY WITH LOWS AROUND FREEZING. TO THE EAST OF
FAIRBANKS A LITTLE WARMER AS CLOUDS MODERATE THE TEMPERATURES.

&&

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE.

&&

.HYDROLOGY...MOST AREAS GOT FOUR TO SIX TENTH OF AN INCH OF RAIN
OVER THE PAST 36 HOURS. THIS WILL BRING THE RIVERS UP A
LITTLE...BUT IT WILL ONLY PRODUCE MINOR RISES IN THE RIVERS.

&&

.FIRE WEATHER...NONE.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

SMALL CRAFT ADVISORY FOR PKZ200-PKZ210-PKZ215-PKZ220-PKZ225-
PKZ230.

GALE WARNING FOR PKZ220-PKZ225.

HEAVY FREEZING SPRAY FOR PKZ510.

&&

$$

SDB SEP 14


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