Graphical Hydro Meteorological Discussion

872
FXAK68 PAFC 211411
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
511 AM AKST Fri Feb 21 2025

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

Discussion:

The Gulf will remain active heading into and through the upcoming
weekend as several systems rotate northwards from the northern
Pacific. These systems will continue to bring mostly rain to the
lower elevations and snow for the higher elevations of the coastal
mountains.

This morning`s system is currently pushing westward across the
Kenai Peninsula with trough extending eastwards along the coast as
it begins to move inland and wash out. Gusty winds in Prince
William Sound over to Turnagain Arm will decrease later this
morning as the low retrogrades back towards Bristol Bay and
gradient relaxes. While a few light showers may make it over the
mountains, the bulk of the precipitation still looks to fall
across the eastern Kenai and western Prince William Sound before
shifting over to the Chigmit Mountains and into the northern
Susitna Valley later this morning. A secondary wave is taking
shape over the northern Gulf as noted on satellite
imagery...lifting north into the western Copper Basin today. This
may allow for a few showers to develop this afternoon.

Another system will lift up across the western Gulf Saturday with
the surface low stalling and lingering near Kodiak Island. To add to
the fun, another system will be working up along the eastern Gulf
coast with a slug of moisture being tugged along with the system. As
has been the case the past several days, the northern Gulf coast
will see the bulk of precipitation from tomorrow`s westward
propagating wave. Although models are in fairly good agreement
through the first half of the weekend...that agreement quickly
dissolves by Sunday as each model wants to take a different track.
Regardless of which track ultimately plays out, the Gulf looks to
remain unsettled with most inland areas of Southcentral remaining
dry, or mostly dry through early next week.

&&


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

Very little regarding the overarching pattern has changed compared
to yesterday, and is not really expected to change much through
the weekend. A broad, disorganized upper level trough with several
embedded smaller features continues to drift over much of the
Bering Sea and Southwest this morning. Very weak flow, both at
the surface and aloft, is translating to only slight movement of
multiple weak lows embedded in the large scale trough in place.
One of these lows is still drifting over the western Bering, and
this feature will continue to wobble in place in the same vicinity
for the next few days. Another small, weak low is drifting slowly
north near Kodiak Island. North of this low, a weak deformation
band of precipitation has developed from the northern AKPen out
to the Dillingham area. This area of rain and snow should diminish
as the band weakens and moves offshore later this morning.

As already mentioned, little change in the pattern is anticipated
for the next several days as light steering flow and weak, slow-
moving features remain the dominant theme. The low in the western
Bering will slowly drift south, then east along and north of the
central/western Aleutian Chain between Saturday and Sunday as it
helps to kick off scattered snow showers. Winds will generally
stay quite weak as the low moves past, generally under small craft
range. Meanwhile, an inverted trough axis will cross over the
Alaska/Aleutian range from the east later today into tonight,
supporting another round of light rain/snow focused primarily over
central and northern portions of Bristol Bay. A compact upper
level low will also drift up from the eastern Aleutians into
Southwest from Saturday into Sunday, prolonging potential for
areas of light snow and rain. Temperatures region-wide will stay
mostly in the 20s and 30s through the weekend, with a slight trend
towards cooler temperatures across Southwest by Sunday.

-AS

&&


.LONG TERM FORECAST (Days 4 through 7) Monday through Thursday.

A broad upper level trough extends from a Siberian low center
across the Bering and into the Gulf of Alaska through the forecast
period. A second low center in the North Pacific works its way
into the Gulf before dissipating by midweek. The flow pattern
starts off chaotic with numerous shortwaves rotating throughout
the system, but becomes smoother and a bit more organized through
Thursday. A couple of low centers slip across the North Pacific to
the South of the Aleutians and Alaska Peninsula with little
effect over Alaskan Waters. A upper level ridge out of Western
Canada builds over Interior Alaska through the week.

A decaying front along the Southcentral coast spreads areas of
rain, rain and snow mixed or snow from Kodiak Island to the
Canadian border Monday. Right on its heels is a second low and
front that continues more active weather over the Southcentral
coastal zones, and extends the precipitation areas into the AKPEN
and Southwest Alaska through through Thursday. In the West, a
series of weakening lows brings mostly rain across the Aleutians
and Bering through the week. A well developed North pacific low
and front approaches the Aleutians for Thursday, and opens with
snow changing to rain beyond the end of this forecast period.

- Kutz

&&



.AVIATION...

PANC...VFR conditions and light northerly winds will persist.
Ceilings could drop below 5000 ft on Saturday morning as a Gulf
low approaches Southcentral, though confidence is high that
ceilings will remain VFR.

&&


$$

432
FXAK69 PAFG 211506
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
606 AM AKST Fri Feb 21 2025

.SYNOPSIS...

Strong winds continue across the North Slope through the Chukchi
Sea down to St Lawrence Island. Periods of blowing snow and
localized ground blizzard conditions are possible, especially from
Point Hope to Point Lay and near Deadhorse. Warmer-than-average
temperatures are expected to continue into this weekend and
through next week. Some light snow is possible at times throughout
the region this weekend into early next week as well.

.DISCUSSION...

Central and Eastern Interior...

- Gusty east winds around 15 to 30 mph will continue over higher
terrain and Summits of the Northern Interior today, diminishing
overnight.

- Above average temperatures.

West Coast and Western Interior...

- Strong northeasterly winds continue from Point Hope through the
Bering Strait towards St Lawrence Island.

- Blowing snow at times with reduced visibility, especially Point
Hope to Point Lay.

- Winds begin to diminish late Saturday.

North Slope and Brooks Range...

- Strong northeasterly winds continue across the North Slope with
gusty winds extending into the Brooks Range.

- Winds diminish across the Brooks Range on Saturday, but likely
persisting across the North Slope through the weekend into next
week.

- Cold wind chills along with areas of blowing snow expected, producing
localized ground blizzards.

Forecast Discussion and Analysis...

Surface high pressure currently resides over the Arctic Ocean with
a broad area of low pressure sitting over the Gulf of Alaska. A
north-south MSLP gradient has set up across most of northern
Alaska promoting a light northeasterly wind through the Interior.
Strong and gustier winds can be found in the higher terrain and
highway summits, and along the western and northern shores. Strong
winds across the North Slope to Point Hope may result in periodic
ground blizzard conditions. Guidance shows weak low pressure
building into the Bering Sea as early as Sunday night, which
allows the MSLP gradient to relax and the winds to therefore
diminish. Further north along the North Slope, the gradient
remains tight and strong winds are expected to persist through the
weekend and possibly into next week.

Extended Forecast Days 4-7...

With broad ridging over Alaska and troughing over the North
Pacific, light mid-level southerly flow across the state has
lead to warmer-than-average temperatures. Ensemble guidance does
not hint at much change in the overall pattern through the weekend
and into the extended period. Occasional light snowfall is
possible at times as weak low pressure centers move northward late
this weekend into early next week, with a stronger low possible by
midweek. Guidance is in relatively poor agreement spatially and
temporally with these features so forecast confidence decreases
regarding snowfall timing and amounts. Light low to mid- level
flow within the ridge may reduce the effects of rain shadowing so
snow may not be confined to just the higher terrain. Snowfall
chances will depend on exactly where these lows track and how they
evolve.

Coastal Hazard Potential Days 3 and 4...None.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Winter Weather Advisory for AKZ801.
PK...Brisk Wind Advisory for PKZ804-805.
Brisk Wind Advisory for PKZ806-807-810-814-850.
Gale Warning for PKZ811-857.
Gale Warning for PKZ812-858.
Brisk Wind Advisory for PKZ813-860.
Gale Warning for PKZ815.
Gale Warning for PKZ816.
Gale Warning for PKZ817-851.
Brisk Wind Advisory for PKZ852.
Brisk Wind Advisory for PKZ853.
Gale Warning for PKZ854-856.
Brisk Wind Advisory for PKZ859.
Gale Warning for PKZ861.
&&

$$

Eckhoff

339
FXAK67 PAJK 211635 CCA
AFDAJK

Southeast Alaska Forecast Discussion National Weather Service Juneau
AK 535 AM AKST Fri Feb 21 2025

.SHORT TERM...The warm and rain-filled weather pattern continues
for SE AK. The mid-level steering flow shows no sign of letting up
in the near future, directing system after system into SE AK A
brief lull between systems through Friday, with the drier weather
largely concentrated across the central and northern panhandle,
will replaced by another system advancing from the S. As the new
low moves north, expect more strong winds and moderate rainfall
for the southern panhandle, and gusty winds and light rain across
the northern half of the area. Elevated snow levels will keep
chances of snow at bay for locations near sea level.


.LONG TERM...The mid range today is very similar to yesterday in
that we will continue to see active weather for the forecast
period. A series of lows will continue to move up from the south
bringing winds, warm weather, and rain to the panhandle. Models
continue to show a consistent trend of moderate rain moving into
the area with some potential periods of heavy rain. At the moment,
there some indications of the potential for prolonged heavy rain
for the central and southern panhandle for next week but that will
still need to be monitored as systems move closer to the area.
Into the start of next week, the likelihood of warm and wet
weather continues to be very likely for the panhandle.

&&

.AVIATION.../12z Friday to 12z Saturday/...Improving flying
conditions have been moving into the area overnight. High-end MVFR
to VFR has been dotting the landscape. However, these better
flying conditions will be brief as the next system and associated
gale force front tracks through today.

LLWS is a big concern today for mainly areas south of Icy Strait.
Latest high-res ensemble guidance gives this area a >70% chance of
seeing LLWS spreading northward from around 14z, reaching Icy
Strait around 21z.

CIG should also see some dips to MVFR as the band of moisture
moves through this morning into this afternoon. Some concern for
brief IFR conditions under the heavier rain bands. VIS should
remain high-end MVFR to VFR.

These lowered conditions and LLWS will last through most of
tonight with better weather moving in Saturday morning.

&&

.MARINE...Another low moves N into the gulf through the day on
Friday, bringing with it more gale force winds. Impactful winds will
mainly be over the SE Gulf and southern inner channels through
Friday before the low moves to the NW and weakens Friday night into
early Saturday. Winds in the inner channels will flip from southerly
back to northerly again as the low moves in on Friday and the
pressure gradient flips. Expect localized outflow winds.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind from noon AKST today through this evening for AKZ330.
MARINE...Gale Warning for PKZ641-661-662.
Small Craft Advisory for PKZ022-033>036-053-642>644-651-652-663-
664-671-672.

&&

$$

SHORT TERM...GFS
LONG TERM....SF
AVIATION...GJS
MARINE...GFS

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