Area Forecast Discussion
Issued by NWS Anchorage, AK

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FXAK68 PAFC 261415
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
515 AM AKST MON JAN 26 2015

.ANALYSIS AND UPPER LEVELS...
THE MAIN UPPER LEVEL TROUGH EXTENDS OUT OF AN UPPER LOW OVER THE
ARCTIC AND EXTENDS SOUTHWARD OVER THE COPPER RIVER BASIN AND
PRINCE WILLIAM SOUND THIS AFTERNOON. THERE IS A SECONDARY TROUGH
THAT IS DIGGING ACROSS THE BERING SEA AND WESTERN ALEUTIANS WHICH
IS KEEPING THE JET STREAM SOUTH OF THE AREA AND SERVING AS THE
FOCAL POINT FOR A SURFACE LOW THAT IS SOUTH OF THE ALEUTIANS AND
HEADING EASTWARD. THE FRONT ASSOCIATED WITH THIS SURFACE LOW IS
PUSHING NORTH OF THE ALEUTIANS INTO THE BERING SEA OVERNIGHT
TONIGHT. A WEAK SURFACE LOW DEVELOPED IN EASTERN PRINCE WILLIAM
SOUND EARLY THIS MORNING AND IS MOVING SLOWLY EASTWARD. THIS
FEATURE ENHANCED SNOW SHOWERS OVER THE VALDEZ AND CORDOVA AREAS
TODAY.

&&

.MODEL DISCUSSION...
MODELS INITIALIZE VERY WELL AND ARE SHOWING GOOD CONSISTENCY FOR
THE FIRST TWO DAYS BEFORE A COMPLEX LOW MOVING TOWARD THE AREA
FROM THE SOUTH TUESDAY NIGHT IS SHOWING QUITE A DIFFERENCE BETWEEN
MODEL SOLUTIONS. AS WITH THE COMPLEX LOW FROM LAST WEEK THE MODELS
HAVE MORE OR LESS A COMMON TROUGH AXIS WHERE THEY PLACE THE LOW.
HOWEVER THE MODELS ARE STRUGGLING WITH THE WAY THE LOW SPLITS ITS
DOUBLE CENTERS AND MODEL SOLUTIONS ARE HUNDREDS OF MILES APART.
THE GFS IS SHOWING ITS TYPICAL ERROR OF CONSOLIDATING ITS ENERGY
INTO A SINGLE LOW CENTER WHICH IS NOT LIKELY TO OCCUR.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (TODAY THROUGH TUESDAY NIGHT)...
THE WIND CHILL ADVISORY ACROSS THE KUSKOKWIM DELTA IS BEING
VERIFIED THIS MORNING...WITH WIND CHILLS OF 40 BELOW TO 45 BELOW
ZERO BEING REPORTED. THE ADVISORY STILL LOOKS TO BE ON TRACK TO
EXPIRE AT NOON TODAY AS TEMPERATURES WARM...BRINGING WIND CHILLS
UP AS WELL. TEMPERATURES ARE GOING TO BEGIN TO MODERATE SOMEWHAT
OVER THE SOUTHWEST MAINLAND BEGINNING TONIGHT...AS A LOW IN THE
NORTH PACIFIC BRINGS SOME WARMER AIR NORTHWARD. THE BIGGEST
CHANGES WILL BE FELT OVER THE KUSKOKWIM DELTA AND BRISTOL BAY
TONIGHT...THEN FARTHER INLAND OVER THE LOWER KUSKOKWIM VALLEY ON
TUESDAY. HOWEVER...TEMPERATURES WILL STILL BE BELOW NORMAL THROUGH
THIS TIME.

AS THE AFOREMENTIONED LOW APPROACHES THE ALASKA PENINSULA FROM THE
SOUTH...SNOW WILL SPREAD OVER THE COASTAL AREAS OF BRISTOL BAY. WE
ARE STILL EXPECTING 3 TO 6 INCHES TO FALL IN THIS AREA...ALONG
WITH BLOWING SNOW AS GUSTY WINDS CONTINUE. INLAND AREAS OF BRISTOL
BAY SHOULD SEE MINIMAL SNOWFALL AS THE PRECIPITATION IS BLOCKED BY
THE ALEUTIAN RANGE.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (TODAY THROUGH TUESDAY
NIGHT)...
TEMPERATURES WILL CONTINUE TO WARM ALONG THE EASTERN ALEUTIANS
AND ALASKA PENINSULA AS THE LOW MOVES TOWARD THE AREA TONIGHT AND
TUESDAY. THIS WILL KEEP PRECIPITATION TYPE AS MAINLY RAIN ACROSS
THIS AREA. FARTHER WEST...WINDS WILL INCREASE ON THE BACK SIDE OF
THE LOW FOR THE CENTRAL AND WESTERN ALEUTIANS FOR THE NEXT COUPLE
DAYS. THE PRIBILOFS WILL SEE SNOW CONTINUE TODAY AND
TONIGHT...THEN TRANSITION TO MORE SHOWERY TUESDAY AFTERNOON.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
A SERIES OF UPPER LEVEL WAVES ASSOCIATED WITH A NORTH PACIFIC LOW
SOUTH OF THE ALASKA PENINSULA WILL CONTINUE TO GENERATE SHOWERY
AND GUSTY CONDITIONS ALONG THE GULF COAST AND ALASKA PENINSULA
THROUGH THE END OF THE WEEK. COLDER AIR FILTERING DOWN OVER THE
CENTRAL AND EASTERN BERING/ALEUTIANS ON THE BACKSIDE OF THIS
SYSTEM WILL KEEP SOME GUSTY WINDS AND INSTABILITY SHOWERS OVER THE
AREA THROUGH THURSDAY AFTERNOON. RIDGING WILL THEN BUILD IN OVER
MUCH OF THE BERING FROM WEST TO EAST BY THE END OF THE WEEK...AND
BEGIN TO EXTEND OVER MAINLAND ALASKA DURING THE WEEKEND. THIS WILL
CONTAIN THE MAJORITY OF PRECIPITATION OVER THE NORTH PACIFIC AND
GULF OF ALASKA...AS WELL AS KEEP DRY AND COLD NORTHEASTERLY FLOW
OVER THE SOUTHWEST PART OF THE STATE. HOWEVER MODELS HAVE STARTED
TO KEY IN ON A WEAK FRONTAL SYSTEM TRACKING THROUGH THE NORTHERN
BERING AND INTO THE KUSKOKWIM DELTA COAST FRIDAY...WHICH COULD
BRING A BRIEF ROUND OF PRECIPITATION AND GUSTY WINDS TO THE AREA.
MODELS ARE ALSO INDICATING A WEAK SURFACE LOW TRACKING TOWARD THE
WESTERN ALEUTIANS SATURDAY MORNING...BRINGING SOME PRECIPITATION
TO THE AREA. HOWEVER FROM SATURDAY MORNING THROUGH EARLY NEXT
WEEK...THE MODELS BEGIN TO DIFFER IMMENSELY FROM EACH OTHER
REGARDING THE TRACK AND STRENGTH OF THIS SYSTEM. MODELS ARE ALSO
STRUGGLING WITH THE PLACEMENT OF ANOTHER LOW APPROACHING THE
SOUTHERN GULF OVER THE WEEKEND. THEREFORE WITH THESE DIFFERENCES
IN THE MODEL SOLUTIONS...FORECAST CONFIDENCE BEGINS TO DRASTICALLY
DIMINISH OVER THE WEEKEND.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WIND CHILL ADVISORY 155.
MARINE...GALE WARNING 130 132 138 150 155 160 165 173 175 176 177
          179 180.
         HEAVY FRZ SPRAY 121 127 129 130 139 140 141 160 179 180
          185.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...MTL
SOUTHCENTRAL ALASKA...MTL
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...MBS
LONG TERM...TP


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