178
FXAK68 PAFC 191415
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
515 AM AKST WED FEB 19 2025
SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3)
DISCUSSION:
THE WEATHER PATTERN CONTINUES TO LOOK ACTIVE FOR THE NORTHERN GULF
COAST WITH SEVERAL SYSTEMS LIFTING UP OUT OF THE NORTH PACIFIC
THROUGH THE END OF THE THE WORKWEEK. THERE WAS A BRIEF RESPITE FROM
THE RAIN FOR MANY COASTAL LOCATIONS OVERNIGHT, BUT WIDESPREAD
PRECIPITATION IS ONCE AGAIN PUSHING ACROSS THE NORTHERN GULF AS OF
EARLY THIS MORNING. PER WATER VAPOR IMAGERY, THE GULF SYSTEM IS
STILL TRYING TO ORGANIZE, WITH MODELS CONTINUING TO DEEPEN IT
THIS MORNING BEFORE THE SYSTEM MOVES ONSHORE AS AN OPEN WAVE LATE
TONIGHT. THE COAST AND PRINCE WILLIAM SOUND WILL SEE THE BULK OF
THE PRECIPITATION BUT ENOUGH MOISTURE MAY SPILL OVER THE CENTRAL
CHUGACH INTO THE COPPER RIVER BASIN RESULTING IN A BAND OF LIGHT
SNOW AS THE WAVE PASSES THROUGH THE BASIN ON THURSDAY. THE NEXT
SYSTEM WILL CLOSELY FOLLOW BEHIND TODAY'S SYSTEM WITH THE LOW
ROTATING UP INTO THE WESTERN GULF THURSDAY MORNING. ITS FRONT
WILL LIFT UP ACROSS THE GULF THROUGH FRIDAY BRINGING ADDITIONAL
PRECIPITATION TO KODIAK, THE EASTERN KENAI, PRINCE WILLIAM SOUND,
AND CORDOVA AND COPPER DELTA REGIONS. MOST LOWER ELEVATIONS ALONG
THE COAST SHOULD REMAIN WARM ENOUGH THAT PRECIPITATION WILL FALL
AS RAIN. WHILE THE GULF COAST WILL SEE SEVERAL ROUNDS OF
PRECIPITATION, EASTERLY WINDS WILL HELP TO KEEP THE WESTERN KENAI,
ANCHORAGE BOWL, AND MAT-SU GENERALLY DOWNSLOPED RESULTING IN
MINIMAL CHANCES FOR ANY MEASURABLE PRECIPITATION.
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3: TODAY THROUGH FRIDAY NIGHT)...
A LOW PRESSURE SYSTEM CLEARLY VISIBLE ON SATELLITE IMAGERY HAS
TRACKED NORTHWESTWARD ACROSS THE ALASKA PENINSULA OVERNIGHT AND
IS CURRENTLY HEADING TOWARD THE PRIBILOF ISLANDS. THIS WILL BRING
ANOTHER ROUND OF SNOW THIS MORNING BEFORE TRANSITIONING TO A
RAIN/SNOW MIX THROUGHOUT THE DAY.
SOUTHWEST ALASKA WILL CONTINUE TO SEE AN ACTIVE WEATHER PATTERN
CHARACTERIZED BY SHOWERY PRECIPITATION AND WARM, SOUTHEASTERLY
FLOW AS ANOTHER NORTH PACIFIC LOW MOVES SOUTH OF THE ALASKA
PENINSULA BY THURSDAY MORNING. MODELS ARE COMING INTO BETTER
AGREEMENT ABOUT KEEPING THIS LOW DOWN THERE INSTEAD OF CROSSING
INTO BRISTOL BAY, AND ALTHOUGH THE MAJORITY OF PRECIPITATION WILL
BE ON THE PACIFIC SIDE OF THE PENINSULA, THE POTENTIAL IS
INCREASING FOR SHOWERS ALONG THE NORTHERN BRISTOL BAY COAST. OUT
WEST, THE LOW TRACKING ACROSS THE PRIBILOFS ENDS UP WRAPPING IN
COLDER AIR TO THE WESTERN BERING SEA THURSDAY AND FRIDAY. STEEP
LAPSE RATES WILL CREATE AN UNSTABLE AIR MASS, BRINGING SCATTERED
SNOW SHOWERS TO THE WESTERN AND CENTRAL ALEUTIANS THROUGH THE END
OF THE WEEK.
LONG TERM FORECAST (DAYS 4 THROUGH 7) SATURDAY THROUGH TUESDAY
LITTLE CHANGE FROM PREVIOUS DISCUSSIONS... 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 WITH EACH SUCCESSIVE SYSTEM.
-DD
AVIATION
PANC...VFR CONDITIONS AND LIGHT NORTHERLY WINDS WILL PERSIST. AS A
WEAK WAVE MOVES ACROSS THE TERMINAL THIS AFTERNOON, CEILINGS WILL
LIKELY REMAIN VFR BUT MAY DROP BELOW 5000 FT. THIS WAVE WILL ALSO
BRING ABOUT A 30% CHANCE OF LIGHT SNOW/RAIN MIX THIS AFTERNOON,
THOUGH ANY PRECIPITATION THAT DOES FALL SHOULD BE MINIMAL.
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