textproduct: Juneau

SYNOPSIS

Key Messages:

-Widespread cold temperatures and cold wind chills last through the weekend and into next week.

LONG TERM

For next week, we'll be watching the potential for a slight shift in the weather pattern that could bring the next round of snow to the panhandle along with some marginally warmer temps.

The long range computer models, both deterministic and ensembles, are trying to put a low pressure center in the northern Gulf of Alaska in the second half of next week. This would allow for the flow to switch to a more onshore pattern. This would weaken the pressure gradient over the panhandle, allowing for wind speeds to weaken a bit beginning around the Tuesday/Wednesday time frame. If/when the low continues its journey eastward, the pressure gradient would tighten up again, allowing for wind speeds to pick back up for the later days of the week.

As far as snow potential, the EURO and Canadian develop a low in the northern Gulf as early as Wednesday. Their respective ensembles mirror this story. The outlier is the GFS. The latest deterministic run keeps the panhandle dry until next Friday. The GFS ensemble average develops a low Thursday with an averaged low pressure center remaining in the gulf through the weekend.

For now, moisture amounts are hinting at if the panhandle sees any snow later next week, it wouldn't be too much for what is normal in SE AK until Friday and the weekend.

The 75th percentiles for the EURO and GFS ensembles give the panhandle less than a tenth of an inch of QPF for Wednesday through Wednesday night, which would give around 1 to 2 inches of snow. For Thursday into Thursday night, the 75th percentiles are giving the area around a quarter to just over a half inch of QPF, with the greater amounts in the GEFS, which would give 2 to 6 inches of snow over 24 hours. For Friday into Friday night, the 75th percentiles are giving the area around a half inch to over an inch of QPF, which would give upwards of 10+ inches of snow over 24 hours.

So what are the main takeaways off all this data? For starters, the 75th percentile is an upper bound. So the amounts mentioned above would be on the high-end for current estimates. Secondly, snow is possible as early as Wednesday but majority of the data is pointing to it not being much if it does happen. Thursday could be a wildcard day that is worth watching closely. Friday and next weekend could be a snowy few days so that will be worth watching closely.

As far as the slightly warmer temps are concerned, there is a warming trend but most of the panhandle is still likely to be below freezing. Monday's highs will be generally in the single digits to teens but by Friday, highs could be in the teens in the far north, 20s and 30s elsewhere. For overnight lows, Monday nights forecasted lows are in the single digits above and below zero with warmer teens to 20s for Friday night. So warmer but still colder-than-normal.

AVIATION

Once again, very stagnant pattern with very little change in message over this TAF issuance. The low pressure bringing MVFR and IFR conditions to the extreme southern panhandle has begun to move inland, once again bringing conditions back up to VFR. A lingering SCT to BKN layer in the area AoA 2500 ft is expected to move out in the next few hours, mostly driven by the extreme cold air from the NE. Kept the LLWS in the northern half from strong cross barrier flow, and still expecting continued mountain wave activity with light to mod turb in the lower levels.

MARINE

Inside Waters: Outflow conditions remain through the weekend, with gale force winds from the north down Lynn Canal, Glacier Bay, Stephens Passage, through Icy Strait, and then out of Cross Sound. A brief lull in the winds ends on Saturday morning. A stronger E-W gradient will also allow some strong breezes to near gales coming out of the Stikine River into Sumner Strait.

Winds once again increase Saturday morning into Sunday as outflow strengthens again. This will bring back strong gales of 40 to 47 kts into Lynn Canal and near Point Couverden. Winds across other north to south facing channels, Chatham Strait and Stephens Passage, and out of cross sound, will increase again to near gales to gale force winds, 28 to 40 kts. Fully developed seas expected down Lynn Canal and Stephens Passage this whole outflow period. Widespread freezing spray for many channels will continue, with heavy freezing spray for Glacier Bay, Lynn Canal, and Stephen's Passage in particular.

Some models are pointing at a weakening pressure gradient mid to late week next week. This would allow for a break in outflow conditions with diminishing winds. Behind that couple day break, the gradient does strengthen once again. We will continue to monitor this potential break from these strong outflow winds.

Outside: Offshore flow continues, bringing increased gap winds off the NE Gulf Coast and stronger NE outflow winds coming out of Cross Sound. Winds will be slowly diminishing to moderate to fresh breezes through Saturday morning.

Outflow gap winds coming off the NE Gulf coast will increase Saturday morning to gale force to strong gales along the outer coastline, to the east of Yakutat down to Cape Spencer. As well as increase wind speeds, wave heights once again build to between 10 and 16 ft Saturday evening into Sunday, with the highest seas expected in the northern Gulf waters.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Cold Weather Advisory until noon AKST Monday for Akz017-322-329- 331. Extreme Cold Warning until noon AKST Monday for AKZ318. Cold Weather Advisory until midnight AKST tonight for AKZ319-320- 325-327. Extreme Cold Warning from midnight tonight to noon AKST Monday for AKZ319>321-325>327. Cold Weather Advisory from midnight tonight to noon AKST Monday for AKZ323-328. Cold Weather Advisory until midnight AKST Sunday night for AKZ324. Extreme Cold Warning from midnight Sunday night to noon AKST Monday for AKZ324. High Wind Warning from 3 AM Sunday to 9 AM AKST Monday for AKZ325. MARINE...Heavy Freezing Spray Warning for PKZ011. Heavy Freezing Spray Warning for PKZ012-013-031. Heavy Freezing Spray Warning for PKZ021-651. Heavy Freezing Spray Warning for PKZ032. Heavy Freezing Spray Warning for PKZ053. Heavy Freezing Spray Warning for PKZ651. Storm Warning for PKZ651. Gale Warning for PKZ011>013-022-031-053-643-644-663-664-671-672. Small Craft Advisory for PKZ021-032>035-652.