Small Craft Advisory 58, NWS Fairbanks, AK

225 
FZAK51 PAFG 242238
CWFNSB

Coastal Waters Forecast for Arctic Alaska
National Weather Service Fairbanks AK
238 PM AKDT Sat Jul 24 2021

Arctic Alaska Coastal Waters out 100 NM

Wind forecasts reflect the predominant speed and direction
expected. Sea forecasts represent the average of the highest one-
third of the combined wind-wave and swell height.

PKZ298-251415-
238 PM AKDT Sat Jul 24 2021

.SYNOPSIS FOR ARCTIC COAST...
A trough of low north of Prudhoe Bay today will weaken tonight as
it moves north. A 1005 mb low 100 nm west of Point Hope will move
to 200 nm east of Wrangel Island at 1002 mb by Mon night. 

$$

PKZ225-251415-
Cape Thompson to Cape Beaufort-
238 PM AKDT Sat Jul 24 2021

.TONIGHT...SE winds 20 kt. Seas 6 ft. Fog.
.SUN...S winds 20 kt. Seas 4 ft. Fog.
.SUN NIGHT...SW winds 15 kt. Seas 4 ft. 
.MON...W winds 15 kt. Seas 3 ft. 
.MON NIGHT...E winds 10 kt. Seas 3 ft. Rain.
.TUE...NE winds 20 kt. Seas 6 ft. Rain.
.TUE NIGHT...SE winds 20 kt. Seas 7 ft. Rain.
.WED...SE winds 30 kt. Seas 9 ft. 
.THU...SE winds 20 kt. Seas 4 ft.  

$$

PKZ230-251415-
Cape Beaufort to Point Franklin-
238 PM AKDT Sat Jul 24 2021

.TONIGHT...SE winds 15 kt. Seas building to 4 ft. Fog.
.SUN...S winds 15 kt. Seas 4 ft. Fog.
.SUN NIGHT...S winds 15 kt. Seas 4 ft. Rain.
.MON...SW winds 15 kt. Seas 3 ft. 
.MON NIGHT...SW winds 10 kt. Seas 2 ft. 
.TUE...NE winds 20 kt. Seas 4 ft. 
.TUE NIGHT...E winds 15 kt. Seas 5 ft. Rain.
.WED...E winds 20 kt. Seas 5 ft. 
.THU...SE winds 15 kt. Seas 4 ft.  

$$

PKZ235-251415-
Point Franklin to Cape Halkett-
238 PM AKDT Sat Jul 24 2021

.TONIGHT...W winds 10 kt becoming E. Fog.
.SUN...E winds 20 kt. 
.SUN NIGHT...E winds 15 kt. Rain and snow. 
.MON...S winds 15 kt. Snow.
.MON NIGHT...S winds 10 kt. 
.TUE...NE winds 10 kt. 
.TUE NIGHT...E winds 15 kt. 
.WED...E winds 15 kt. 
.THU...E winds 15 kt.  

$$

PKZ240-251415-
Cape Halkett to Flaxman Island-
238 PM AKDT Sat Jul 24 2021

.TONIGHT...W winds 10 kt. Fog.
.SUN...SW winds 10 kt. Fog.
.SUN NIGHT...SE winds 10 kt. 
.MON...S winds 15 kt. Rain and snow. 
.MON NIGHT...S winds 10 kt. 
.TUE...S winds 10 kt. 
.TUE NIGHT...E winds 10 kt. 
.WED...E winds 10 kt. 
.THU...SE winds 10 kt.  

$$

PKZ245-251415-
Flaxman Island to Demarcation Point-
238 PM AKDT Sat Jul 24 2021

.TONIGHT...W winds 15 kt. Seas 3 ft subsiding. Fog.
.SUN...W winds 10 kt. Seas 2 ft. Fog.
.SUN NIGHT...E winds 10 kt. Seas 1 foot. 
.MON...E winds 15 kt. Seas 2 ft. 
.MON NIGHT...SW winds 10 kt. Seas 2 ft. 
.TUE...S winds 10 kt. Seas 2 ft. 
.TUE NIGHT...E winds 10 kt. Seas 2 ft. 
.WED...E winds 10 kt. Seas 2 ft. 
.THU...E winds 10 kt. Seas 2 ft.  

$$

Jul 21

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
240 PM AKDT Fri Jul 23 2021

.SYNOPSIS...
Summer weather is holding on with the threat for strong
thunderstorms and heavy rainfall over the Eastern Interior today
and into Saturday. Thunderstorms will develop along the Eastern
Brooks Range and Arctic Coast tomorrow as a front shifts east. Out
west it remains cool and damp with an upper level trough sitting
over the Seward Peninsula, with several more moving in through
early next week.

&&

.DISCUSSION...

Upper Levels and Analysis...
Little change from yesterday with a 567 dam upper level closed
high over the Yukon Flats and a shortwave trough over the West
Coast. In between is a stretching deformation zone. Showers and
thunderstorms are already popping up over the Interior high
terrain in association with an "easterly wave" moving underneath
the upper high. There is a thermal low over the Fortymile Uplands,
which is pretty close to right under the upper high.

Model Discussion...
The models are still a bit uncertain of exactly where the highest
precipitation will fall, but there are in much better overall
agreement with the easterly wave pattern. It looks like the
heaviest core will fall over the Alaska Range with values around
0.3-0.75" over most of the Tanana Valley with a sharp cutoff over
the Minto Flats. Either way, this will represent the most rain in
parts of the Interior in a long time, which has manifest in a D1
drought. Model clarity remains good for tomorrow too as a
shortwave ejects the Eastern brooks Range and brings widespread
thunderstorms across the Brooks Range to the Arctic Coast, east of
the Dalton. All models are in close agreement. Overall, models
remain in good agreement until day 4 as a potential heavy rain
storm forms over the West Coast and pushes inland, with some
models holding it wrapped up over the West Coast, while others
bring rain inland in southwest flow. For now, we will use a blend
of the high res models in the short term and the GFS and EC for
the extended.

Central and Eastern Interior...
Storms are already popping and will eventually merge into a band
of heavy rainfall from the Alaska Range north to the Tanana
Valley, and east to the Fortymile Uplands. Up to 0.5-1" of
rainfall is possible with some local near 2" values in the Alaska
Range. The rain band will shift east tomorrow as a front merges
with it and then exits to the east through the afternoon. There
will be more thunderstorms tomorrow both over the southeast Brooks
Range as well as over the far Eastern Interior toward the ALCAN.
Cooler and more stable air moves into the Interior Sunday and will
last through Monday.

West Coast and Western Interior...
Cooler and damp with intermittent showers and light rain as a weak
upper trough moves to the east. Another trough will bring rain to
the West Coast tomorrow evening through Monday and possibly longer
as a firehose of rain sets up over the West Coast, mainly from the
Seward Peninsula northward. The Interior will be much drier until
increasing chances of rain develop Monday.

North Slope and Brooks Range...
Showers over most of the North Slope as a shortwave trough tracks
west to east through tomorrow. Scattered thunderstorms today over
the eastern brooks Range with locally heavy rain and frequent
lightning. The trough will intersect a strong thermal trough over
the Eastern Brooks Range tomorrow and there will be a local region
of significant thunderstorms and very heavy rain from the Brooks
Range to the coast east of Prudhoe Bay. Some storms will likely
move offshore, too, give the strong forcing aloft and favorable
storm motions. Rain moves into the western Arctic and Brooks Range
on Saturday night and will spread rain chances east through
Tuesday.

Extended Forecast Days 4-7...
Beginning the extended period forecast on Monday, there will be a
skinny ridge over the Alaska Range with broad westerly flow aloft
over the North Slope and West Coast, moving into the Interior.
Expect rain along the West Coast and that rain also moving across
the North Slope. It will be on the drier side for the Interior,
but as the ridge weakens and the trough out west moves inland,
rain chances increase as broad southwest flow develops, with the
possibility of a broad rain event over much of the Mainland
Tuesday and Wednesday, as now both the GFS and ECMWF are on board
with this pattern. Stay tuned...it would represent a big change in
weather as we head toward the end of summer.

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

&&

.FIRE WEATHER...
Last day for very active thunderstorms as the thermal trough gets
shifted east into the Yukon the next two days. Active scattered
thunderstorms today will turn to heavy rainfall overnight over the
Eastern Interior with one more day of thunderstorms tomorrow
afternoon toward the ALCAN. There will be a widespread area of
scattered thunderstorms over the Eastern Brooks Range tomorrow as
a trough ejects the mountains. Thereafter, the thermal trough
retreats int the Yukon and more cool and damp air moves inland.
Rain looks more likely in a west/southwest flow pattern early
next week from the West Coast to the Interior.

&&

.HYDROLOGY...
Heavy rain over the next day in the Central and Eastern Alaska
Range, Fortymile Country, and Brooks Range with up to 1.5 inches
of rain additional will lead to small streams rising rapidly to
bankfull with possible minor flooding. This rainfall is not
expected to impact the larger mainstem rivers as they continue to
run well below normal levels. For the latest river information go
to www.weather.gov/aprfc.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning for AKZ220-AKZ222-AKZ224.

Small Craft Advisory for PKZ210-PKZ220.

Brisk Wind Advisory for PKZ245.

&&

AHSENMACHER JUL 21