Area Forecast Discussion
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

000
FXAK67 PAJK 231339
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
539 AM AKDT Wed May 23 2018

.SHORT TERM.../Through Thursday night/ Low will continue to weaken
over the western gulf through today. A stalled occluded front just
E of the southern panhandle will move away from the area by this
evening. Upper trof will move NE across the area late this
afternoon and tonight. Another occluded front will move NE into
the eastern gulf by Thu evening. Used 00z GFS/06z NAM blend to
handle things through 12z Thu, then went with mainly the 06z NAM
after that.

Main forecast concerns will be precip potential, winds, and fog.
As of 13z, most precip was in a band over the far S area,
associated with the stalled front. As the front moves off, expect
the precip there to diminish during the day. Elsewhere, there are
some showers over the gulf that get to the NE gulf coast. These
showers will continue there today, and eventually they will move
E into the panhandle later this afternoon and tonight as upper
trof moves in. Am expecting the most showers along the Coast Mtns
and NE gulf coast tonight. Then, rain with the next front moving
in should push into the eastern gulf Thu afternoon, then likely
spread onshore Thu night as front nears.

Most of the stronger winds today will be around the weakening low,
and will stay over the N and central gulf. 15-20 KT winds are
expected today in those areas. Winds will increase over the gulf
Thu as next front moves in, and SCA level winds are now expected
by Thu afternoon over the central gulf, then reaching the
remaining gulf by Thu evening.

Over the inner channels, with weak pressure gradient today, not
much wind attm, with generally 10 kt or less. Some local effects
will increase winds over the N to 15 kt this afternoon. Pressure
gradient will build tonight as high pressure ridge builds in, so
winds should increase to 10-20 kt, with strongest winds over the
N. There may be a bit of a lull in the stronger winds Thu, but
approach of the next front will increase winds some by Thu
evening. Not expecting any SCA level winds over the inner channels
though.

With breaks in the clouds this morning, some radiation fog has
developed. It is not very persistent though as there are some
stratocu clouds that drift across the area that thin the fog out.
Visibilities have dropped as low as 1/4 mile, but this has not
lasted for very long. Am expecting any radiation fog to dissipate
fairly quickly this morning as it is also very shallow. The far S
will have generally low clouds and rain enhanced fog this morning
as well, but visibility will not be as low as further N. This fog
should diminish as the precip diminishes this afternoon. Not
expecting much in the way of fog tonight due to a bit more mixing
with upper trof moving through, as well as more cloud cover.

.LONG TERM.../Friday through Wednesday as of 10 PM Tuesday/
Models continue to be in good agreement to the advancement of lows
that will move into the gulf. On Friday a low will be in the
western gulf with the associated weather front rolling up on the
Panhandle. There looks like there could be a short but weak break
in the precipitation for the southwestern portion of the Panhandle
Friday night as one weather front advances east and the before
the next front comes across the gulf.

The next low should be in the southwestern portion of the gulf by
Saturday morning with its associated weather front already making
its way onshore of the Panhandle and likely spreading rain over
the area from south to north through the day. The low will move
into the central gulf Sunday night, continuing on to the
Fairweather Grounds before taking a turn to the southeast and
filling Monday into Tuesday. The theme for the holiday weekend
is: wet, but not windy. By Wednesday a ridge of high pressure
will build over the Panhandle and give a better chance of
some sunny breaks.

We have been watching the second low and it is still on track to
bring SCA to the outer coastal areas of area 51 and 52 briefly
early Friday morning. Elsewhere winds will to 15 kt or less
through Wednesday, with the southern inside waters showing favor
for 20 kt Friday through Friday night. Lowered temperatures a
couple of degrees for the weekend with little, if any, insolation
occurring. Temperatures are still expected to remain in the mid
to upper 50s during the day and range into the 40s overnight.

The ECMWF was used to nudge the forecast, resulting in small
changes overall.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...None.
MARINE...None.

&&

$$

RWT/Ferrin

Visit us at http://www.weather.gov/Juneau



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.