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000
FXAK69 PAFG 172224
AFDAFG
Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
224 PM AKDT Fri May 17 2024
.SYNOPSIS...
Overall model consensus this afternoon shows a low in the
Gulf of Alaska which has forced the upper-level ridging over Eastern
Alaska to retreat to the north some. Meanwhile, a large upper-level
trough remains is moving into the Bearing Sea with a small shortwave
trough near the Seward Peninsula into the Western Interior. This
pattern has generally kept things quiet weather wise for the region
despite some showers popping up over the White Mountains this
afternoon. The upper-level low in the Gulf of Alaska will quickly
dig into southeast Alaska which in turn will allow the upper-level
ridge to dig back to the south towards the Gulf of Alaska through
the day Saturday. Meanwhile, the upper-level trough over the Bearing
Sea will gradually push towards the Alaska Peninsula during the day
Saturday before crossing into the Gulf of Alaska by Sunday afternoon
and then tracking more easterly towards southeast Alaska into
Monday. Model discrepancy increases as we head into next week, but
the overall theme would have a few upper-level lows moving through
the state.
&&
.DISCUSSION...
Central and Eastern Interior...
We did increase temperatures some across the Interior for this
afternoon based off some current trends, however, the overall
story remains the same with temperatures in the mid 60s with some
developing CU in the Tanana Valley with some showers over the
White Mountains. Saturday could be slightly warmer than today with
a chance for some isolated showers and thunderstorms. Sunday will
be the best chance for thunderstorm activity for the Interior as
a low pressure system cuts through the region. This will also
bring some snow over the eastern Alaska Range and some portions of
the southeast Interior.
West Coast and Western Interior...
Still seeing more calm and drier conditions across the West Coast
this afternoon that should continue into the remainder of the
weekend despite the approaching trough to the west, with the
exception of St. Lawrence Island that could still see some
precipitation through tonight. We will also see a warming trend
across the West Coast as we head into the weekend with increasing
chances for precip for the Western Interior.
North Slope and Brooks Range...
Above normal conditions will come to an end as chinook winds
begin to end this evening with east to northeast winds increasing
for both Saturday and Sunday due the strengthening of the Arctic
High. As a result, we should see a return of some stratus and fog
to the northern slope with temperatures returning to more of a
normal range.
Coastal Hazard Potential Days 3 and 4...None.
&&
.FIRE WEATHER...
Isolated thunderstorms remain possible for most of the Interior for
Saturday with increasing chances for Sunday. RH values on Saturday
will bottom out around the lower to mid 20 percent range for the
Yukon Flats and northern Alaska Range southeastward to Northway. The
rest of the Interior will be in the upper 20 to upper 30 percent
range. Similar conditions will be seen for Sunday across the same
areas. Gap winds will increase Saturday night into Sunday morning
for across the Alaska Range, however, the peak of the winds will
come during a time when RH values are increased and should weaken
before we reach our min RH values, so no Red Flag concerns as of
right now.
&&
.HYDROLOGY...
We have seen some hydrology concerns across the West Coast from the
heavy rains near ice-covered rivers and streams. But we have seen
improvement with the dry weather that is in place. This trend will
continue as dry conditions will be in place through the weekend. The
Yukon remains ice covered towards the Delta, however, there is no
real concern of any ice jam at this point.
&&
.AFG WATCHES/WARNINGS/ADVISORIES...
AK...None.
PK...Small Craft Advisory for PKZ801.
Small Craft Advisory for PKZ817.
Brisk Wind Advisory for PKZ850.
Small Craft Advisory for PKZ851.
Brisk Wind Advisory for PKZ854.
&&
$$
BT
000
FXAK68 PAFC 180027
AFDAFC
Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
427 PM AKDT Fri May 17 2024
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)...
A weak surface ridge will push north into the northern Gulf of
Alaska, bringing some breaks in the clouds and slightly warmer
temperatures to much of Southcentral on Saturday. Gusty
southeasterly gap winds, particularly out of the Turnagain and
Knik Arms and in the Copper River Basin will also develop ahead of
an approaching low and front. Cloud cover and upslope showers
along the coast will increase in coverage Saturday evening through
early Saturday night.
A strong low over Bristol Bay supported by a deep and
unseasonably cold upper level low over the Bering Sea will
strengthen as it pushes east over the Alaska Peninsula and over
Kodiak Island by Sunday morning, sending another period of
precipitation back into the island. As the upper low and
accompanying surface low move into the western Gulf, precipitation
will also overspread the eastern Kenai Peninsula and into the
Prince William Sound through Sunday morning. As the upper low hugs
the coast and moves inland, shortwaves on its western periphery
will allow precipitation to fill in over the Copper River Basin
late Sunday into Monday. The Eastern Kenai and Prince William
sound will see the heaviest precipitation while the Western Kenai,
the Anchorage Bowl and the MatSu will see lesser amounts with
drying downslope flow and gusty southeasterly gap winds.
-ME
&&
.SHORT TERM FORECAST SOUTHWEST ALASKA, THE BERING SEA AND THE ALEUTIANS
(Days 1 through 3: This afternoon through Monday evening)...
The forecast remains on track with the main player in the near-
term being a large upper-level trough that extends southward
through the Bering Sea. The upper-low within the trough will
continue dropping southward through the central Bering tonight and
into Saturday, bringing cold air with it as it does so. A stronger
short-wave rounding the base of the trough will induce
cyclogenesis on the Pacific side of the southern Alaska Peninsula
(AKPEN) tonight. This low will pull Pacific moisture northward and
into the AKPEN through Saturday. While most precipitation will
fall along the Pacific side of the AKPEN, the precipitation
forecast is a little more uncertain for the Bering side
communities due to southeast winds blowing across the Aleutian
Range and creating downslope drying.
Meanwhile, further north along the Kuskokwim Delta coast and
Nunivak Island, there will be enough cold air in place to create a
period of snow this evening into Saturday morning as the front
lingers across the southwestern mainland coast. Accumulations will
be light. This front pushes inland Saturday as the trough becomes
more negatively tilted. The main precipitation-type with the
system will be rain with northern areas of the Kuskokwim Delta and
Nunivak Island eventually turning over to rain as temperatures
warm during the day. The other story with this system will be the
easterly winds coming out of Kamishak Gap and impacting areas such
as Koliganek, New Stuyahok, and Iliamna with gusts up to 50 mph
Saturday and into Saturday evening. The main upper-low then
shifts to the Gulf of Alaska for Sunday with some weak shortwaves
left on the backside of the broad trough. This will help keep some
isolated showers going for interior portions of Southwest for
Sunday. Most of mainland Southwest clears out for Monday except
for some light precipitation confined to the higher terrain.
Further to the west, next weather-maker will be a Kamchatka low
and its front making their way to the western Bering by Saturday,
spreading small craft winds and rain along the western Aleutians.
The front will weaken as it moves eastward toward the central
Aleutians by Sunday. However, the trailing front will be a little
stronger with perhaps some more enhanced precipitation for the
central Aleutian Chain late Sunday night into Monday. The low
itself moves to the central Bering by Monday as the front sweeps
eastward to the Pribilof Islands, eastern Aleutians, AKPEN, and
eventually to the mainland coastline of Southwest by Monday
evening.
&&
.LONG TERM FORECAST (Days 4 through 7)...
A persistent northwest to southeast oriented longwave trough will
remain over the Bering with waves of lows moving into the
northern Gulf during much of the first part of the extended
period. This series of low pressure systems that move through the
Alaska Peninsula and into Kodiak Island will bring coastal rain
showers and interior cloudy and isolated rain showers. Toward the
end of next week, a stronger low pressure system will move
through Shemya into the Bering Sea and push the longstanding
trough eastward. Indications are that the persistent trough and
strong low could move in a more northeastward direction as high
pressure progresses northward through the north Pacific.
DJ
&&
.AVIATION...
PANC...VFR conditions and light winds will persist through
Saturday morning. Gusty southeasterly winds out of Turnagain Arm
are expected to develop Saturday afternoon.
&&
$$
000
FXAK67 PAJK 172329
AFDAJK
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
329 PM AKDT Fri May 17 2024
.SHORT TERM.../through Saturday night/...Overall 500mb pattern
has a weak low tracking out of the area with a ridge building back
up for Saturday. This ridge is all ahead of the next system that
will arrive on Sunday.
As the weak low tracks SE, lingering isolated to scattered showers
will last into Friday night. But as the low moves farther away from
SE AK, we`ll lose the upward forcing so showers will fade out. This
will end up giving the panhandle a dry day Saturday with partly
sunny skies.
Because of the surface ridge, general south winds are expected.
Through the short term, winds are expected to be on the lighter side
but late Saturday night, winds could start to pick up ahead of the
next front.
.LONG TERM.../ Sunday through Wednesday night / Frontal band
sweeps through Eastern Gulf of Alaska and the Panhandle. Gale
force winds ahead of the front into the Northeast Gulf Coast, and
then Small Craft Advisory to the inside waters. Trailing showers
and the remains of the low in the Northeast gulf will get moved
into the panhandle Monday. Rain / showers will be tapering off
Monday headed into Tuesday.
High pressure builds into the gulf Tuesday then moving towards the
panhandle Wednesday as yet another front spreads into the western
gulf Wednesday.
&&
.AVIATION...Cloud cover will continue for the panhandle as we see
some clearing in the skies before clouds could redevelop this
evening. These clouds that are expected to be across the area will
be VFR to MVFR cloud cover. As we head into the day tomorrow,
cloud cover is expected to decrease even more as high pressure
moves into the panhandle. This should allow for some increased sea
breezes during the day tomorrow. Clouds are expected to start to
move in but will be towards the end of the TAF period.
&&
.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Gale Warning for PKZ652-672.
Small Craft Advisory for PKZ651-671.
&&
$$
SHORT TERM...GJS
LONG TERM....Bezenek
AVIATION...SF
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