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FXAK68 PAFC 181409
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
509 AM AKST TUE FEB 18 2025
SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3)
MOST OF THE ACTIVE WEATHER THIS WEEK WILL BE FOCUSED ALONG THE
COAST, WHERE EASTERLY FLOW WILL LEAD TO PERSISTENT PRECIPITATION
THROUGH THURSDAY. AN OCCLUDED FRONT OVER THE NORTH GULF COAST
THIS MORNING WILL CONTINUE TO WEAKEN THROUGH TODAY. THIS WILL
ALLOW PRECIPITATION TO LIGHTEN UP TONIGHT OFF BEFORE REJUVENATING
AGAIN ON WEDNESDAY AS ANOTHER SURFACE LOW MOVES TOWARDS THE COAST.
THE LOW DISSIPATES AS IT MOVES ONSHORE WEDNESDAY NIGHT AND IS
QUICKLY FOLLOWED BY A THIRD FRONT EXTENDING OFF A NORTH PACIFIC
LOW APPROACHING THE ALASKA PENINSULA ON THURSDAY. THIS MORE
COMPACT SURFACE TROUGH PASSES OVER SOUTHCENTRAL WEDNESDAY NIGHT-
THURSDAY AND HAS THE POTENTIAL TO CARRY OVER MORE WIDESPREAD BUT
LIGHT PRECIPITATION, ESPECIALLY FOR LOCATIONS ALONG THE COPPER
RIVER BASIN.
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3: TODAY THROUGH THURSDAY NIGHT)...
THE WEATHER PATTERN ACROSS WESTERN ALASKA WILL CONTINUE TO BE
ACTIVE FOR THE NEXT FEW DAYS, WITH A STEADY STREAM OF SHORTWAVE
ENERGY FROM THE NORTH PACIFIC USHERING IN WARMER TEMPERATURES TO
THE ALEUTIANS AND SOUTHWEST. A LOW PRESSURE SYSTEM CURRENTLY
SITTING JUST SOUTH OF THE ALASKA PENINSULA (AKPEN) WILL CONTINUE
TO MOVE NORTHWESTWARD, TRAVERSING INTO THE BERING SEA AND BRINGING
MODERATE RAIN SHOWERS TO THE EASTERN ALEUTIANS AND AKPEN THROUGH
TOMORROW MORNING. CONFIDENCE HAS GROWN THAT ITS ASSOCIATED FRONT
WILL BRING A WAVE OF SNOW SHOWERS AND GUSTY WINDS TO THE PRIBILOF
ISLANDS THIS AFTERNOON. BLOWING SNOW IS EXPECTED THROUGH THIS
EVENING, WITH VISIBILITIES DROPPING BELOW ONE MILE DURING HEAVIER
SHOWERS. CONDITIONS ARE FORECAST TO IMPROVE TONIGHT AS WINDS
DIMINISH.
AS THE LOW TRACKS INTO THE SOUTHERN BERING SEA THROUGHOUT THE DAY
ON WEDNESDAY, THE PRIBILOFS WILL LIKELY SEE AN ADDITIONAL ROUND
OF SNOW BEFORE TRANSITIONING TO A RAIN/SNOW MIX BY WEDNESDAY
EVENING. BY THURSDAY MORNING, ANOTHER LOW MOVING UP FROM THE NORTH
PACIFIC WILL SKIRT SOUTH OF THE AKPEN AND ENTER THE WESTERN GULF,
CONTINUING A PATTERN OF SHOWERY WEATHER FOR THE AKPEN AND WARM,
SOUTHEASTERLY FLOW INTO SOUTHWEST ALASKA FOR THE END OF THE
PERIOD.
LONG TERM FORECAST (DAYS 4 THROUGH 7) FRIDAY THROUGH MONDAY
THE PERSISTENT BROAD UPPER LEVEL TROUGHING OVER THE BERING SEA
AND ALEUTIANS, COMBINED WITH THE STRONG UPPER LEVEL RIDGING OVER
MUCH OF THE ALASKAN MAINLAND AND ALONG THE PANHANDLE, WILL
CONTINUE TO DOMINATE THE WEATHER PATTERN THROUGH THE FORECAST
PERIOD. EQUAL WEIGHT WAS GIVEN BETWEEN ALL OF THE GLOBAL MODELS
WHICH HAVE COME INTO RELATIVE AGREEMENT WITH THE LARGER FEATURES.
HOWEVER, THERE IS SOME UNCERTAINTY ABOUT TIMING AND INTENSITY OF
THE UPPER LEVEL SHORTWAVES AND ASSOCIATED WEAK SURFACE LOWS.
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. THIS STUBBORN WEATHER
PATTERN WILL BRING A MORE SOUTHERLY WIND PATTERN AND UNSEASONABLY
WARMER TEMPERATURES ACROSS MUCH OF THE REGION WITH HIGHER
PRECIPITATION AMOUNTS FALLING MAINLY AS RAIN ALONG THE NORTHERN
GULF COASTLINE AND THROUGH THE CENTRAL ALEUTIANS. THERE IS A
POTENTIAL FOR HEAVY SNOW ACCUMULATIONS IN THE HIGHER COASTAL
ELEVATIONS.
-DD
AVIATION
PANC...LIGHT NORTHERLY WINDS AND VFR CONDITIONS TO PERSIST.
SOUTHEASTERLY WINDS ALOFT WILL PRODUCE WEAK TO MODERATE WIND SHEAR
THROUGH THIS AFTERNOON.
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