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FXAK68 PAFC 171255
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
355 AM AKST MON FEB 17 2025
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA
(DAYS 1 THROUGH 3: TODAY THROUGH WEDNESDAY EVENING)...
RAIN AND HIGHER ELEVATION SNOW CONTINUES TO FALL OVER COASTAL
SOUTHCENTRAL THIS MORNING AS A SURFACE TROUGH AND UPPER-LEVEL
SHORTWAVE MOVE FROM THE NORTHERN GULF TO THE IMMEDIATE COAST. A
SECOND TROUGH, OUT AHEAD OF THE FIRST, IS MOVING OVER THE ALASKA
RANGE AND SOUTHWEST ALASKA, KEEPING AN AREA OF LIGHT SNOW IN
PLACE OVER THE WESTERN SUSITNA VALLEY. THIS BAND OF SNOW WILL
LIKELY DIMINISH LATER THIS MORNING BEFORE REFORMING AS THE
AFOREMENTIONED TROUGH AND SHORTWAVE MOVE INLAND.
A SURFACE TROUGH AND UPPER-LEVEL SHORTWAVE OVER THE SOUTHWESTERN
GULF THIS MORNING WILL LIFT TO THE SOUTHCENTRAL COAST BY THIS
EVENING, HELPING REINFORCE MOISTURE ADVECTION AND SOUTHEASTERLY
WINDS ALOFT OVER THE SOUTHCENTRAL COAST. THE RESULT WILL BE AN
UPTICK IN PRECIPITATION ALONG THE COAST AS WELL AS UPSLOPE AREAS
ALONG THE ALASKA RANGE. WITH SNOW LEVELS RISING ABOVE 1,500 FT,
ACCUMULATING SNOWFALL WILL REMAIN CONFINED TO THE HIGHER
ELEVATIONS. SNOW MAY MIX WITH RAIN ALONG THE COAST LATE TONIGHT
INTO EARLY TUESDAY DUE TO A QUICK PUSH OF COLDER AIR OVERNIGHT
BEFORE TEMPERATURES PUSH BACK TO AROUND 40F FOR TUESDAY FOR PLACE
LIKE WHITTIER, PORTAGE, AND SEWARD.
THE CHALLENGE IN THE SHORT TERM WILL BE THE EXTENT OF
PRECIPITATION SPILLING OVER THE CHUGACH AND KENAI MOUNTAINS LATER
THIS MORNING AND AGAIN LATE TONIGHT AND INTO EARLY TUESDAY. AS OF
THE LATEST GUIDANCE (06Z), CHANCES ARE SLIM TO NONE; HOWEVER, IF
ANY PRECIPITATION DOES SPILL OVER, IT WILL LIKELY FALL AS A MIX OF
RAIN/SLEET/SNOW, SIMILAR TO THE PLETHORA OF PRECIPITATION TYPES
OBSERVED FROM KENAI TO ANCHORAGE AND TALKEETNA YESTERDAY. MUCH
LIKE YESTERDAY, ANY WINTRY MIX IS EXPECTED TO BE VERY LIGHT, WITH
ONLY TRACE ACCUMULATIONS.
ANOTHER FRONTAL SYSTEM LIFTS NORTHWARD ACROSS THE GULF FOR
TUESDAY. THIS WILL SPREAD ANOTHER ROUND OF PRECIPITATION FROM
KODIAK ISLAND TO THE NORTH GULF COAST AND PRINCE WILLIAM SOUND
THROUGH THE DAY. MORE SEA-LEVEL RAIN WITH SNOW IN THE MOUNTAINS
CAN BE EXPECTED WITH THIS SYSTEM. INLAND AREAS IN THE LEE OF THE
MOUNTAINS ALSO LOOK TO REMAIN ON THE DRIER SIDE AS WELL. THE STORY
REMAINS THE SAME FOR WEDNESDAY AS EAST-SOUTHEAST FLOW CONTINUES
OFF THE GULF AND PRINCE WILLIAM SOUND WHICH WILL KEEP UPSLOPE
PRECIPITATION GOING AS WELL AS DOWNSLOPE DRYING IN THE LEE OF THE
MOUNTAIN RANGES.
-TM/DAN
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3: TONIGHT THROUGH WEDNESDAY)...
A COMPACT UPPER LEVEL LOW CROSSING THE ALASKA PENINSULA INTO THE
EASTERN BERING LAST NIGHT HAS SHIFTED THE PATTERN OVER SOUTHWEST
ALASKA TO A RELATIVELY WARMER AND MORE MOIST AIRMASS, BRINGING A
WAVE OF PRECIPITATION TO BOTH THE BRISTOL BAY AND KUSKOKWIM DELTA
REGIONS. THE INITIAL SURGE OF MOISTURE WILL HAVE MOVED OVER
BRISTOL BAY BY EARLY THIS MORNING, SPREADING A MIX OF RAIN, SNOW,
AND FREEZING RAIN ACROSS LARGELY COASTAL BRISTOL BAY INCLUDING
KING SALMON AND DILLINGHAM. BY THIS AFTERNOON, THE HEAVIEST
PRECIPITATION WILL HAVE SHIFTED NORTH, HOWEVER THERE WILL BE A
LINGERING CHANCE OF PRECIPITATION OVER BRISTOL BAY THROUGH TUESDAY
MORNING. AS SUCH, A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR
BRISTOL BAY FOR FREEZING RAIN WITH THE POTENTIAL FOR SNOW AND
BLOWING SNOW LARGELY ALONG THE WESTERN CAPES OF THE REGION THROUGH
NOON TUESDAY.
AS THE SYSTEM ADVANCES NORTHWESTWARD OVER THE KUSKOKWIM DELTA,
THE AXIS OF STRONGEST MOISTURE WILL HAVE WEAKENED, BUT WITH
OFFSHORE WINDS STILL FAIRLY GUSTY, SNOW AND BLOWING SNOW IS
POSSIBLE BEGINNING THIS AFTERNOON, LINGERING THROUGH TUESDAY
AFTERNOON. BY MONDAY AFTERNOON, SNOW AND PERSISTENT NORTHEASTERLY
OFFSHORE WINDS WILL BE CONDUCIVE FOR PERIODS OF BLOWING SNOW
ACROSS THE KUSKOKWIM DELTA COAST, INCLUDING KIPNUK, KWIGILLINGOK,
AND MEKORYUK, REDUCING VISIBILITY AT TIMES THROUGH TUESDAY
MORNING. ADDITIONALLY, FREEZING RAIN SIMILARLY APPEARS A
POTENTIAL FOR AREAS OF THE KUSKOKWIM DELTA, HOWEVER GIVEN THE
DIMINISHED MOISTURE SIGNAL AND LESS CERTAINTY REGARDING LOW-LEVEL
TEMPERATURES, LESS IMPACTFUL ACCUMULATIONS ARE EXPECTED.
THEREFORE, THE SPECIAL WEATHER STATEMENT REMAINS IN EFFECT FOR A
WINTERY MIX OF PRECIPITATION AND GUSTY WINDS FOR THE KUSKOKWIM
DELTA FROM THIS AFTERNOON THROUGH TUESDAY AFTERNOON. THIS FRONT
ADVANCING NORTHWESTWARD WILL ALSO BRING A BRIEF WAVE OF SNOWFALL
TO THE PRIBILOFS BEGINNING TUESDAY MORNING, COMING TO AN END BY
TUESDAY AFTERNOON. SOME AREAS OF BLOWING SNOW IS POSSIBLE WITH
THIS WAVE, HOWEVER SIGNIFICANT REDUCTIONS IN VISIBILITY IS NOT
EXPECTED AT THIS TIME.
THE REMAINDER OF THE PERIOD WILL LARGELY BE CHARACTERIZED BY A
STEADY STREAM OF SHORTWAVE ENERGY FROM THE NORTH PACIFIC, KEEPING
THE WEATHER PATTERN ACTIVE ACROSS THE BERING SEA AND BRINGING
WARMER TEMPERATURES ACROSS THE ALEUTIANS AND SOUTHWEST ALASKA. A
BROAD LOW PRESSURE SYSTEM IS SET TO REACH THE SOUTHERN SHORES OF
THE ALEUTIAN CHAIN AND AKPEN MONDAY AFTERNOON, BRINGING A CHANCE
OF LIGHT RAIN THROUGH THE PERIOD TO MANY OF THE ALEUTIAN ISLANDS,
WITH THE HEAVIEST RAIN EXPECTED TO BE FOCUSED ALONG THE EASTERN
ALEUTIANS AND AKPEN. AS THE LOW TRACKS NORTHWESTWARD ACROSS THE
ALEUTIANS AND INTO THE BERING SEA THROUGHOUT THE DAY ON WEDNESDAY,
SOUTHWEST ALASKA IS EXPECTED TO REMAIN DRY AND WARMER WITH HIGH
TEMPERATURES NEARING 30 DEGREES AND LOW TEMPERATURES IN THE LOW
20S FOR THE LOWER KUSKOKWIM VALLEY AND KUSKOKWIM DELTA.
-CL
.LONG TERM FORECAST (DAYS 4 THROUGH 7) THURSDAY THROUGH
SUNDAY...
NO SIGNIFICANT CHANGE FROM THE PREVIOUS DISCUSSION... THE BROAD
UPPER LEVEL TROUGHING OVER SOUTHERN AND WESTERN PART OF THE STATE
WILL PERSIST. THIS COUPLED WITH THE MODERATELY STRONG HIGH
PRESSURE RIDGE ALONG THE STATE'S SOUTHEAST COASTLINE AND INTO THE
CENTRAL INTERIOR OF THE STATE WILL DOMINATE THE WEATHER PATTERN
THROUGH THE FORECAST PERIOD. EQUAL WEIGHT WAS GIVEN BETWEEN THE
GFS, EUROPEAN AND CANADIAN MODELS WITH THE UKMET STILL BEING THE
CONSISTENT OUTLIER.
THIS PATTERN WILL ALLOW FOR SMALL, FAST MOVING SHORTWAVE TROUGHS
AND ASSOCIATED SURFACE FRONTS TO QUICKLY MOVE ACROSS THE ALEUTIAN
ISLANDS AND COASTAL SOUTH CENTRAL REGIONS. THERE IS SOME
UNCERTAINTY ABOUT TIMING AND INTENSITY WITH THESE SERIES OF
TROUGHS AND LOWS. HOWEVER, WITH A MORE SOUTHERLY WIND PATTERN,
TEMPERATURES WILL BE UNSEASONABLY WARM ACROSS MUCH OF THE REGION
WITH HIGHER PRECIPITATION AMOUNTS FALLING MAINLY AS RAIN ALONG THE
NORTHERN GULF COASTLINE AND THROUGH THE CENTRAL ALEUTIANS WITH
POTENTIALLY HEAVY SNOW ACCUMULATIONS IN THE HIGHER COASTAL
ELEVATIONS.
-DD
AVIATION
PANC...LIGHT NORTHERLY WINDS AND VFR CONDITIONS ARE EXPECTED TO
PERSIST.
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