Weather Service Report


362 
FXAK67 PAJK 142316
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
316 PM AKDT Sun Oct 14 2018

.SHORT TERM...Satellite imagery and surface analysis indicate a
frontal boundary across the N central panhandle with another wave
traversing the NE along the boundary out of the NE Pac. This will
allow the gradient to relax ever so slightly this afternoon/evening
as the frontal boundary begins to be pull back NW. The gradient
will tighten over the N gulf again Mon with a gale force Ely barrier
jet developing along the N gulf coast. Winds will remain gusty but
have diminished below headline criteria. Expect breezy conditions
to persist through Mon with potential for strong wind headlines
for the N gulf coast Mon evening. Sat imagery continues to show
deep moisture advecting into the region so expect continued
periods of moderate to heavy rain N of Frederick Sound. As wave
approaches the boundary will push slightly E before regressing NW,
so kept mention of chc precip this evening over the S panhandle.
Precip amounts will range from a few hundredths to a tenth S of
Sumner Strait with widespread amounts from 1-4 inches with
localized amounts to 6 inches along the outer coast and flood
advisories are in effect for AKZ018>022-025. Model solutions 
remain in good agreement with the synoptic pattern including winds
and precip amounts. With clearer skies and lighter winds over the
S panhandle, added some patchy fog overnight into Mon mainly S of
Sumner Strait. Inherited forecast represented this well with 
adjustments mainly to account for current trends and add mention
of fog overnight into Mon. Overall, forecast confidence remains 
above average.

.LONG TERM.../Tuesday through next weekend, as of 10 PM 
Saturday/...Tuesday will begin with the remnants of the 
atmospheric river (AR) slowly dissipating over southeast Alaska. 
Occasional heavy rainfall may still occur Tuesday morning, 
especially along the northeast Gulf coast; however, Tuesday's 
rainfall totals will be significantly less than those of this 
weekend. A brief dry period will occur after the AR ends. Late in 
the week the next low will move into the Gulf; this system 
continues to look very fall-like and will likely carry a band of 
gale force winds along its associated front as well as a period of
heavy rain for portions of the Panhandle. The weekend as a whole 
looks active with a second low tracking into the Gulf on Sunday.

Very little change was made in the extended forecast. With
stronger winds and high chances of precipitation already 
introduced yesterday associated with the low that pushes into the 
gulf Friday, changing these fields would not add value to the
existing forecast. Currently, it is still too difficult to 
accurately speculate where and when the low will ultimately end up
tracking. Ensemble spreads remain large with operational models 
in poor agreement with the handling of the system. Forecast 
confidence remains above average Tuesday and Wednesday; however, 
it is below average beyond that timeframe.

&&

.AVIATION...Widespread MVMC conditions along with breezy winds,
LGT-MDT turb and some LLWS prevail Sun afternoon. Little change
expected through the forecast outside of conditions lowering to
IMC in heavier precip. Conditions over the S panhandle not as
breezy as N of Sumner Strait, but MVMC cigs persist. Some clearing
expected over the S panhandle overnight with some patchy fog 
developing late resulting in IMC by Mon morning. 

&&

.MARINE...Winds have diminished slightly this afternoon with gales
lowered over N Lynn Canal. However, gales continue over Cross 
Sound but are expected to ease further this evening. Elsewhere, in
the inner channels advisory level winds persist and expected to
continue through Mon.

&&

.HYDROLOGY...An atmospheric river continues to produce mdt-hvy
precip over the N central inner channels this afternoon. A
secondary wave will push this feature slightly E then back NW
tonight. Expect precip amounts to ease slightly this evening then
increase late as the boundary begins pushing back NW. The Taiya 
River, Mendenhall Lake and Montana Creek along with the ungauged 
rivers and streams over the N central inner channels are currently
under flood advisories through Mon. Rapid rises from moderate to
heavy rains are possible along with mudslides in steeper terrain. 

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Areal Flood Advisory until noon AKDT Monday for AKZ019>022-025.
     Areal Flood Advisory until 7 AM AKDT Monday for AKZ018.
MARINE...Gale Warning for PKZ022-043-051-052. 
     Small Craft Advisory for PKZ012-013-021-031>036-041-042-053. 

&&

$$

BC/JB

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