Area Forecast Discussion
Issued by NWS Juneau, AK

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FXAK67 PAJK 040006
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
306 PM AKST Sun Mar 3 2024

.SHORT TERM...Outflow conditions continue this afternoon but
continue to weaken as the pressure gradient between BC and SE AK
decreases. Temperatures have warmed up again today with the clear
conditions across most of the panhandle. But with the clearing
skies and decreasing winds, overnight temperatures will continue
to be cold. Single digit temperatures are likely during the
overnight hours. After the cold start to Monday morning, clouds
will start to move into the area ahead of the next system.
Precipitation will be limited to the NE gulf coast for the short
term period with snow starting in Yakutat Monday evening. The
heaviest snow looks to be during the overnight and Tuesday morning
hours before snowfall rates start to decrease and the snow mixes
with rain.

.LONG TERM.../Tuesday through Friday/...The forecast next week is
still calling for a change in the weather pattern with the return
of snow to the panhandle. The rounds of weather seem to be
centered around Tuesday, Wednesday, and Friday.

Quick notes:
-Snow for those along Icy Strait and along the far northeast gulf
coast on Tuesday.
-Heavier snow moves in Wednesday with snow switching to rain/snow
 mix or rain beginning Wednesday night from south to north.
-Thursday into Friday, snow continues to switch to rain from south
to north as the next low pressure system moves tracks in from the
south.

Details:
Confidence is high that SE AK is looking at a pattern change this
week. For starters, a weak low looks to track along the southern
coast, near Anchorage, on Tuesday. This low will swing a front
towards the panhandle, bringing precip, most likely snow, to the NE
coast, and to those along and north of Icy Strait.

A Winter Weather Advisory has been issued for the Yakutat area. This
advisory begins late Monday evening and lasts into Tuesday morning.
Expected snowfall amounts are around 4 to 6 inches before rain
starts to mix in with the snow.

For those along Icy Strait, Tuesday into Tuesday night expected
snowfall amounts are around 1 to 4 inches.

For Wednesday, another low will enter the gulf from the west. This
low will swing another front that will bring precip to the
panhandle. The precip will likely start as snow. The question is
will any of it switch to rain? Among the deterministic models, the
EURO is the most aggressive in bringing in a wedge of warmer air
over the outer coast and Prince of Wales Island. The GFS barely
brings that wedge to Prince of Wales Island. Both have the warm
air getting overtaken by colder air. For their ensembles means,
both keep the area at -6C or colder. This would imply mostly snow.

For the NBM precip-type probabilities, at 9AM Wednesday, the
panhandle has 60-90% chance of snow, lowest probabilities in the far
southern Prince of Wales Island.

Fast forward to 3PM Wednesday, the outer coast, looks to be rain.
Probabilities for rain along the coast are 50-80%. Precip-type snow
probabilities for the inner channels at this time are around 30-60%
for along and south of Frederick Sound. North of Frederick Sound
have snow precip-type probabilities around 60-70%.

Fast forward to 9PM Wednesday, precip-type probabilities for rain
start to really ramp up. Upwards of 50-90% for those along the coast
and south of Icy Strait. Along and north of Icy Strait, still could
have snow. Precip-type probabilities for snow are still around 40-
60%, so not a complete slam dunk on precip-type.

For Wednesday into Thursday, snowfall amounts are around 1 to 5
inches for any 12-hour time frame. As we get more data and
confidence increases, more Winter Weather Advisories may need to be
issued.

Next round of weather will come on Friday as a low tracks northward.
Ahead of this low will be warmer air, so any snow leftover on
Thursday will transition to a mix, then rain. The exception might be
Northern Lynn Canal area where northerly winds may keep snow in
place.

But Friday`s low will bring up much warmer air that will give most
of the area rain. An early look at 24 hour rainfall estimates gives
a range of about a 0.50 inches to 1.50 inches. At this time, there
is some concern for roadway/urban flooding due to the snowpack,
but we are still several days out so that part of the forecast
will need to be adjusted as latest data comes in.

No matter how you slice it though, this next week is worth watching
closely and staying up on the latest info.

&&

.AVIATION...The quiet aviation weather for the panhandle with
prevailing VFR conditions prevailing will last for about another 24
hours before the next weather front moves in. Front hits the NE Gulf
Coast Monday afternoon and evening then shifts southeastward.
Turbulence and LLWS around the Stikine Delta and Juneau due to
strong outflow winds will diminish as the pressure gradient shifts
and weakens into Sunday night and heading into Monday.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Weather Advisory from 9 PM Monday to noon AKST Tuesday
     for AKZ317.
     Wind Chill Advisory until noon AKST Monday for AKZ318.
     Strong Wind until 6 PM AKST this evening for AKZ318.
     Strong Wind until 3 PM AKST this afternoon for AKZ325.
MARINE...Small Craft Advisory for PKZ012-013-021-022-031-032-035-643-644-
     663-664.

&&

$$

SHORT TERM...SF
LONG TERM....GJS
AVIATION...PRB

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