Area Forecast Discussion

UPDATE.../to add the 18z aviation section/

SYNOPSIS

Key Messages:

- Chances of showers linger into the weekend with seasonably cool temperatures

- Front will be brushing the southern panhandle Sunday with some rain and some gusty winds.

- Leaning towards drier and slightly warmer conditions for early next week

SHORT TERM

Quiet yet damp morning across the panhandle today. The remains of yesterday's front is still present in the form of a weakening band of rain stretching from Wrangell south to central Prince of Wales island. Otherwise the rest of the panhandle is still sitting under a shield of clouds with the occasional light showers here and there. Winds are mostly light.

Overall forecast for the next few days has not changed all that much. For this weekend, the remains of the front will diminish by midday. What will be left is a ridge over the panhandle and general W to SW onshore flow from the gulf. This will keep cloud cover around and a chance of showers in the forecast for much of the weekend. This will also result in temperatures remaining cool and winds low as with the lack of warm temperatures, afternoon sea breezes will not be very strong.

One complications to the weekend forecast is a front that will be advancing on the SE Gulf and southern panhandle on Sunday, but is not expected to get any farther north then that. That feature is still looking to bring S to SE winds of 15 to 25 kt for the SE gulf and southern panhandle mainly toward Sunday afternoon and evening. Also the front will shift the higher chances of rain to the southern panhandle on Sunday though the amounts of precip are only expected to be light.

LONG TERM.../Monday through Friday/

The upcoming week will be shaped by several evolving systems. The main story begins with the tail end of a weak low pressure system entering the Gulf on Sunday. This system will bring elevated southeasterly winds to the southern panhandle, specifically from Hecate Strait up through southern Chatham Strait, accompanied by light precipitation across the southern region on Monday. Current model runs indicate this low is tracking further south and drying out, so expect winds and precipitation to taper off fairly quickly by Monday midday.

Looking toward the mid-week period, the pattern shifts to mostly zonal flow from Tuesday evening through Wednesday and cooler, more seasonable temperatures follow. A weak front is expected track across the panhandle. While this front brings increased wind potential to the Lynn Canal area on Tuesday evening due to a tightening pressure gradient, the overall dynamic forcing remains weak. A 500mb trough building Tuesday night may support light rain showers into Wednesday morning, though any activity will be largely terrain-driven, characterized by onshore flow and primarily isolated to the southern region. Post-front, high pressure will build south of the panhandle, near Haida Gwaii, and although this ridge is expected to be relatively weak, it may allow for some clearing. High temperatures look to remain in the mid 50s to mid 60s, north to south respectively, and a slight warming trend is expected by the end of the week.

By Friday, a stronger low tracks into the western Gulf from the central Pacific. An associated shortwave trough could bring a surge of moisture to the region, but ensemble models disagree on timing and track. The GEFS favors a faster, southerly path toward the southern panhandle by Thursday afternoon, whereas the ECMWF Ens suggests a slower progression toward the north coast near Icy Bay with a more disorganized flow against high pressure. Stay tuned for updates throughout the week.

AVIATION.../Until 18Z Sunday/

For the northern Panhandle, a marine layer low stratus deck continues to be the primary concern through the forecast period. This will continue to bring down CIGs & sometimes VISs to well within the MVFR flight category. CIGs may temporarily dip down into IFR, as well, at times. The main exception will be the northern Lynn Canal area, especially PAGY, which will start out as VFR and eventually lower to MVFR tonight. For the southern Panhandle, rain showers currently positioned in a band that stretches from just east of Wrangell to just east of Hydaburg continues to push southeastward, completely departing the region this afternoon. This should improve flight conditions up a bit from the MVFR/VFR category range temporarily, but then the marine layer looks to periodically influence that area, as well, for the remainder of the period, bringing flight conditions back down to within the MVFR category. As for SFC winds, they will be breezy/gusty out of a southerly to southeasterly direction due to a tightened pressure gradient over the northern Lynn Canal region(PAGY & PAHN) through this evening. Elsewhere, SFC winds look to stay rather benign. LLWS values continue to not be a concern through the TAF period, as well.

MARINE

Inner Channels: Southerly winds of 15 kt or less are prevalent across the inner channels this morning. The only exception is N Lynn where winds of 24 kt are currently blowing. Generally expect the low wind conditions to continue for today and for Sunday mainly for the north (N Lynn may stay around 25 kt today before diminishing tonight into Sunday). The southern inner channels will have the northern edges of a front increasing southerly winds to 25 kt into Clarence Strait and Prince of Wales especially by Sunday afternoon and evening before decreasing again into Monday. Seas mainly 3 ft or less for the period, but N Lynn today and Clarence Sunday could see seas up to 5 to 6 ft due to the higher winds expected there at that time.

Gulf Waters: Generally S winds of 15 kt or less across the gulf today, but an incoming front from the S will increase winds in the southern gulf Saturday night into Sunday. Winds are expected to top out around 25 kt out of the SE Sunday mainly west of Prince of Wales Island, while other areas of the gulf will mainly see 20 kt or less. Winds then diminish back to 15 kt or less out of the E this time into Monday. Seas are rather quiet with mainly 5 ft or less combined seas with little in the way of swell. The front on Saturday night into Sunday is expected to build seas to 8 to 10 ft mainly for areas E of 141 W before they gradually subside again into Monday to 6 ft.

AJK WATCHES / WARNINGS / ADVISORIES

PUBLIC...None. MARINE...Small Craft Advisory for PKZ012-036-641-642-644-652-661>664-671- 672.