Graphical Hydro Meteorological Discussion

243
FXAK68 PAFC 200103
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
503 PM AKDT Fri Sep 19 2025

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Today
through Sunday)...

Wet weather along the Gulf coast continues through tonight as
waves of moisture continue to rotate into the coast, with
scattered light showers pushing further inland. Rain showers are
expected to gradually taper off Friday night for inland locations
with rain lingering along the coast through the early morning
hours on Saturday.

Southcentral Alaska will get a break from the rain Saturday as
the low in the Gulf tracks further to the east in the southern
Gulf. The southerly flow shifts to light northerly across
Southcentral on the back side of the low, promoting a drying trend
both along the coast and inland through Saturday evening. The
break in active weather will be short lived as the pattern
continues to progress with the next upper level trough pivoting
across the Alaska Peninsula into the Gulf for Sunday. Rain again
looks to fill in across much of Southcentral as the formation of
weak low pressure in the northern Gulf and east to southeasterly
flow aloft keeps the region unsettled through the end of the
weekend. Heading into early next week, a similar scenario looks
likely to play out as northerly flow between systems again
promotes drier weather for Monday.

&&


.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days
1 through 3: Today through Sunday night)...

A broad, vertically stacked low pressure system in the Gulf of
Alaska continues to drive the northerly flow and overall benign
weather pattern across Southwest Alaska. Ongoing showers and gusty
winds across the southern Alaska Peninsula will diminish tonight
as the upper-level wave continues to shift out of the area into
the Gulf. Through tonight though, expect gusty winds up to 45 mph
through southern gaps and passes, including near King Cove and
False Pass. While wind speeds are expected to diminish by Saturday
morning across the region, wind direction will remain generally
out of the north, resulting in a continued cooling trend across
the region.

By Saturday night into Sunday morning, a new upper-level shortwave
will move over Bristol Bay and the Alaska Peninsula, re-amplifying
the gusty winds and returning the rainfall to the area. Stronger
northerly flow will tap into the cooler air mass over the Bering
Strait down into southeastern parts of the Bering Sea through
Sunday night, maintaining the cooling trend. Winds will again
become strong and gusty along and south of the AKPen by Sunday
morning, with gusts to around 40 to 50 mph likely near favored
gaps and passes along the Pacific side. Out over the western
Aleutians, the outer reaches of a much stronger system will begin
to extend strong easterly winds and rain into the region late
Sunday night.

-CL

&&


.LONG TERM FORECAST (Days 4 through 7: Tuesday through
Friday)...

An active fall pattern continues for southern Alaska through the
long term forecast period. Upper level troughs tracking across the
region will bring unsettled weather to the Aleutians and
Southcentral as they move west to east. On Tuesday, the lingering
low pressure system in the northern Gulf will bring coastal winds
and moderate rain to Prince William Sound. Showers in the lee of
mountains are possible but heavier precipitation should stay
confined to coastal areas. Meanwhile, a strong low tracking across
the Bering Sea will bring gusty winds and rain to the Aleutian
Chain. An occluded low is expected to form along its front and
move into the Gulf of Alaska on Wednesday, reinforcing another
round of locally heavy rain along the north Gulf coast by
Thursday. Northerly gap winds through the bays and passes of the
Alaska Peninsula will increase as the pressure gradient briefly
tightens over the region Thursday and Friday. A new system looks
to lift up from the North Pacific and begin impacting the western
Aleutians starting Friday. A period of calmer and dryer weather is
possible for Southcentral at the start of next weekend as the
region sits between two systems, but confidence is low as model
agreement this far out is still quite poor.


&&

.AVIATION...

PANC...Mostly VFR conditions are expected, but should any clearing
occur overnight, low stratus may redevelop given the moist
environment. Winds will remain light and variable. Light rain
showers will be on and off through tomorrow morning, but a brief
drying trend is expected for the rest of the day Saturday.

&&
$$

836
FXAK69 PAFG 201124
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
324 AM AKDT Sat Sep 20 2025

.SYNOPSIS...
A mostly quiet weather pattern with typical fall like weather
continues for much of Northern Alaska. Temperatures will be
gradually cooling this weekend and into next week as an arctic
troughs drops southeast from the arctic. There`s also a low in the
Gulf and these two systems will both bring chances for rain and
snow showers across much of the area. By Tuesday of next week, the
two systems will join forces and bring a chance for snow in the
Interior, especially in the higher terrain from the AK Range north
and east. An active pattern may develop thereafter. More details
on that will be in the "extended forecast" portion.

&&

.KEY WEATHER MESSAGES...
Central and Eastern Interior...
- Scattered showers over the Eastern Interior with isolated
showers over the Central Interior today, lessening in coverage
tomorrow.

- Rain in the Alaska Range with snow above 4000 feet this
afternoon through tomorrow.

- An arctic trough drops into the Interior Monday afternoon,
showers increase in coverage and snow levels drop to 1000 feet
or less north and west of Fairbanks, 1500-2500 feet from
Fairbanks south/east.
- Light snow possible in the White Mountains and hills around
Fairbanks, more likely in the Alaska Range Passes and less
likely southeast of Fairbanks in the Eastern Interior/Upper
Tanana Valley.

- Temperatures in the low to mid 50s for highs this weekend, mid
to upper 40s Monday/Tuesday. Widespread frosts and freezes more
likely by Tuesday night.

West Coast and Western Interior...
- Isolated showers across Western Alaska, most likely from McGrath
northward this afternoon through Monday afternoon.

- An arctic trough arrives Monday and drops temperatures for most
of next week.

- Highs this weekend are warmest today, in the upper 40s to low
50s, then drop each day with highs in the low to mid 40s Monday
and Tuesday.

North Slope and Brooks Range..
- Onshore flow keeps stratus and areas of fog across the North
Slope and Brooks Range.

- An arctic trough drops over the North Slope Monday morning
bringing areas of light snow to the Western Arctic Coast.
- Light accumulations around 1 inch possible through Tuesday.

- Light snow develops over the Central Brooks Range Monday
afternoon and shifts east through Tuesday with light
accumulations around 1 to 3 inches possible.

- Snow showers persist across the North Slope Tuesday.

- Temperatures in the mid 30s along the coast and 20s to low 30s
in the Brooks Range.

&&

.FORECAST ANALYSIS AND DISCUSSION...
The state of Alaska remains under the influence of broad troughing
aloft as we head into the weekend. This includes two upper lows
as of this morning. One is over the Gulf while the other one is
over the Beaufort Sea. The one in the Bering Sea will bring a
front to the Interior today with scattered showers over the
Eastern Interior and isolated showers in the Central Interior.
Expect rain in the Alaska Range as well. The front will weaken
tomorrow with shower chances lessening in coverage.

Early next week will see the Arctic low strengthens and sends an
arctic front southward across the North Slope and West Coast
resulting in noticeably colder temperatures in these areas and
allowing for some of that arctic chill to seep into parts of the
Interior as well. The Gulf low will send a stronger warm front
north over the Alaska Range. This will bring higher rain chances
to much of the Interior with higher elevations seeing snowfall.
The higher terrain of the White mountains may well see a light
accumulation of snow early next week while the Parks highway
through the Alaska Range could also be impacted as rain changes
over to snow as well.

&&

.HYDROLOGY...
No concerns at this time.

&&

.EXTENDED FORECAST DAYS 4-7...
Persistent onshore flow should keep chances for snow showers
through the end of next week on the North Slope. The West Coast
should remain quiet but chilly as the arctic trough brings colder
temperatures with highs in the 40s. In the Central and Eastern
Interior, expect a cooler pattern as the arctic trough drops
south. A low entering the Gulf from the Bering Sea next week may
bring another chance for rain and snow across the Interior and
Alaska Range Thursday and Friday.

On Friday, models are honing in on a strong low in Eastern Russia
which could bring the first chance for accumulating snow to much
of the Interior. Many ECMWF, GFS and CMC ensemble members are all
showing the potential for several inches of snow from the Western
Interior to the Eastern Interior by next weekend. One caveat,
there is still a high amount of uncertainty in the strength and
placement of the low. It may very well take a track into the
southern Bering Sea, but many ensemble members are beginning to
cluster the low near the Chukotka Peninsula with a storm track
east-northeast. If it did pan out like this, it would bring
southwest flow to Northern Alaska and plenty of moisture. This
coupled with cold air in place would thus result in snow. We will
continue monitoring the ever evolving pattern through next week.

Coastal Hazard Potential Days 3 and 4...None

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...None.
PK...Small Craft Advisory for PKZ801.
Small Craft Advisory for PKZ802.
Small Craft Advisory for PKZ806-807-816-817-854-856.
Small Craft Advisory for PKZ810.
Small Craft Advisory for PKZ811-857.
Small Craft Advisory for PKZ815.
Small Craft Advisory for PKZ850.
Small Craft Advisory for PKZ851.
Small Craft Advisory for PKZ853.
Small Craft Advisory for PKZ861.
&&

$$

Bianco

309
FXAK67 PAJK 200548 AAA
AFDAJK

Southeast Alaska Forecast Discussion...UPDATED
National Weather Service Juneau AK
948 PM AKDT Fri Sep 19 2025

.UPDATE...Quick update for the0 6z TAF/aviation forecast package
release. In addition, a Flood Advisory has been issued for
Ketchikan Panhandle through 10 AM Saturday due to ongoing heavy
rainfall.

.SHORT TERM.../ though Saturday night / One front moving through
SEAK and secondary impulse of energy moving inland with its
copious amounts of moisture. The higher rain rate of .2 to .3
inches are falling in the around Ketchikan and Metlakatla and
should persist through much of the evening. The showers will
continue through Saturday and into Saturday night. To add to the
fun, a pool of more unstable air is trailing the second system,
and stronger convection, including the possibility of isolated
thunderstorms that spread into the southwest coastal areas and
southern panhandle saturday. Localized areas of heavy rains and
gusty winds from outflows will be the main impacts from this as
they move from sw-w to easterly direction.


.LONG TERM.../Sunday through Wednesday/...
Key Messages:
- Brief breaks in rain and wind possible Sunday between systems
- Fast moving gale force system to move northward into the eastern
gulf Sunday night into Monday
- Heavy rain again for far southern panhandle
- Showers continue across the panhandle through midweek

An active fall pattern will continue through the weekend and into
early next week across southeast AK. The major rain event over the
area will start to wind down going into Sunday. Being in a post
frontal environment, moderate rain showers are still possible but
breaks between showers are more likely through midday.

This reprieve will not last long as a fast moving gale force low
moves into the eastern gulf late Sunday night into early Monday
morning. This system will bring another round of heavy rainfall to
the southern panhandle, with ensemble guidance giving up to a 50%
chance of upwards of 3 inches in 24 hours for Metlakatla and
Ketchikan. For the central outer coast including Sitka, guidance
gives a 60% chance of up to 2.5 inches over 24 hrs. These 24 hour
totals are for Sunday at 4pm through Monday at 4pm. Contingent upon
the speed and track of this feature, the timing of heaviest rainfall
is expected early Monday morning. Light to moderate rain will then
spread over the rest of the panhandle from south to north as the low
moves along the outer coast. There is still some model discrepancy
on whether this feature will slowly deteriorate and jump inland in
the vicinity of Mt Fairweather, or if it will weaken, but stay
offshore and continue to meander NW along the gulf coast. This will
largely depend upon the larger circulation in the mid levels
steering it towards the panhandle in the first place.

If the system moves inland near Mt Fairweather, this would lead to
increased storm totals for the northern panhandle, as well as a
longer duration of increased winds for the inner channels. A more
westerly track lingering in the northern gulf would allow for near
gales to continue along the near coastal waters for a bit longer.
Before the primary deviation point, there is model agreement on
strong gale force winds for the southeast gulf and Dixon Entrance
area as the low approaches, with gusts to storm force possible
for far southern Clarence Strait early Monday morning. Seas in the
southeast gulf will also build to 15 ft with a strong
southwesterly swell as the system moves northward through Monday
afternoon.

On the backside of this early week system, there will be
persistent on shore flow with light to moderate showers across the
panhandle through midweek. Throughout the long term forecast
period, maximum temperatures will remain mild between the mid 50s
in the north ranging to around 60 in the southern panhandle.

&&

.AVIATION...Generally, not the most optimum 24 hour period to be
flying across SE Alaska, especially for VFR pilots. For the most
part, overnight we can expect IFR conditions to prevail ahead of
the next front moving in off the eastern Gulf of Alaska. As the
next batch of heavier precipitation ahead of the front moves in
conditions should generally drop to IFR during the evening hours
(if not sooner). The airport with the possibility of staying
mostly MVFR is Sitka, but again heavy bands of precipitation are
noted moving in ahead of the front on the Biorka Island NexRad
Radar, so again we expect significant periods of IFR there too.
Most of the more significant LLWS 40 kts or so is expected to be
across the southern Panhandle around Ketchikan and Wrangell
tonight. AFter the front moves through Saturday afternoon, some
improvement in ceilings and visibilities is possible, however
southwesterly winds will increase behind the front and we could
see more LLWS issues going into late Saturday, with another
frontal band arriving late Saturday night.

&&

.MARINE...
Outside (Gulf and Coastal Waters): Winds in the 15 to 20 kt range
with spots of 25 kt as the next feature moves into the southern
panhandle. Seas will continue hold up around 8 to 10 feet. So
small craft advisory will persist through the day Saturday.


Inside (Inner Channels): Winds will remain elevated before
diminishing and starting to flip around in response to the new low
moving into the eastern Gulf tonight. Wave heights are expected
to remain around 3-5 ft for most channels. Locations south of Icy
Strait are expected to remain out of the south as the low tracks
to the north closer to Yakutat Bay but remains offshore.


&&

.HYDROLOGY...Heavier rains have spread in over the southern
panhandle with rain rates in the Ketchikan and Metlakatla region
in the 0.2 to 0.3 hour rates which should continue for a fair
portion overnight. A flood watch is out for the southern third,
and in particular for the Ketchikan and Metlakatla regions. A
flood advisory has been issued for the Ketchikan area through 10
AM AKDT Saturday due to ongoing heavy rainfall.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Flood Watch through Saturday evening for AKZ326-328>332.
MARINE...Small Craft Advisory for PKZ022-036-053-641>644-651-652-661>664-
671-672.

&&

$$

SHORT TERM...Bezenek
LONG TERM...STJ
AVIATION...GFS
MARINE...Bezenek
HYDROLOGY...Bezenek

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