Area Forecast Discussion
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
000
FXAK67 PAJK 211605
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
705 AM AKST Tue Nov 21 2017

.SHORT TERM...Model agreement had starting to slip, with regards
to the placement of the low center in the gulf and the next
system, as well. The one feature that has never faltered is the
tighter gradient over the northern Panhandle and along the Coast
Mountains. Models just cannot decide whether there will a low
center or just a TROF running along the outer coastal waters
Wednesday. This gradient will relax along the coast mountains
starting Wednesday afternoon as another low moves up from the
south somewhere off the coast of Prince of Wales.

Snow falling over much of the Panhandle, with rain in the Gateway
City, Prince of Wales and up along the outer coast up around
Sitka. The warmer air will slow push northward bringing a mix and
eventually rain for the central portion of the Panhandle this
afternoon. Temperatures will again go below freezing for the
central area and so rain will turn back to a mix or all snow. Snow
accumulations mostly be less than an inch overnight. This morning
is another story with a Winter Storm Advisory continuing for
Gustavus, Hoonah, Angoon and Juneau. Snowfall rates have been
healthy with 2-3 inches falling for most areas, Angoon seems to
have had a slow start with a weak dry slot that developed over the
area overnight. Rain should decrease for the southern Panhandle
this morning but more rain is on the way by the evening.

Winds are finally diminishing in Cross Sound and Northern Lynn
Canal, with the Gales fading into SCA this morning. SCA along the
outer coastal areas, with some inside waters also having 25-30 kt
of wind, higher gusts are also adding an additional hazard to
mariners.

A blend of GFS and NAM might work well for placement of the next
system come Wednesday. The SREF has a great handle on the
precipitation for making some changes, most of the changes were
needed in the southern Panhandle and Yakutat area today. A minor
perturbation near Yakutat Bay made for some periods of snow early
this morning. Satellite is already showing this breaking apart.

.LONG TERM /Thursday through Sunday/...The second half of the
week will see a system over the SE corner of the panhandle
departing to the east on Thursday followed quickly by a front and
its associated low pressure moving into the central gulf from the
west.

For Thursday expect precip along the central and southern Coast Mts.
to shift off to the east through mid day followed by a bit of a
break. Then precip starts to arrive with the front from the west
going into late afternoon and evening. Have moved up the rain/snow
line for this timeframe and places like Hoonah/Gustavus and downtown
Juneau could see a mix Thursday night and Friday. The p-type
forecast remains a challenge however and confidence is lower than
normal. Temperatures at 850mb across the central panhandle look to
hover around the -6C mark that we like to see for snow through
Friday, then things cool a bit more through the weekend.

The low looks to slowly shift to the south through Saturday and take
majority of the precip with it. Have a chance or less in the
forecast for Sunday, lowest POPs across the northern panhandle.

Updates to this forecast package were minor for pressure/wind.
Adjusted temperatures up some in the mid range and lowered values
over the weekend.

&&

.AVIATION...

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Winter Weather Advisory until 9 AM AKST this morning for AKZ020-
     021-024.
     Winter Weather Advisory until noon AKST today for AKZ025.
MARINE...Gale Warning for PKZ012-013.
     Small Craft Advisory for PKZ021-022-031-032-035-036-041>043-
     051>053.

&&

$$

KV/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.