Marine Forecasts

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7 Day Forecast for Marine Location Near Cordova, AK

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Area Discussion for -

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FXAK68 PAFC 210207 AFDAFC

Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 507 PM AKST Mon Jan 20 2020

ANALYSIS AND UPPER LEVELS. The pattern is dominated by a broad upper level trough centered over the West Coast of AK. This is not an overly strong feature, but just happens to be in the right location to take advantage of some moisture over the North Gulf Coast up through Cook Inlet. The moisture is associated with a weak surface low sitting just south of the Kenai Peninsula. As this trough continues to take on a negative tilt today, it is aiding in lifting the moisture through the column. With cold air in place, the net result in fairly widespread snow from the Kenai Peninsula up through the Mat-Su Valleys and over to Valdez. We had a few reports of near 6 inches from Kenai early this morning and it continues to snow from Kenai north. Over the Bering, cold air advection snow showers continue to be the dominant feature. For SW AK, there is plenty of low stratus spreading over the area with some patchy fog mixing in, especially along the coast.

At 300 mb (30,000') the jet is supporting the trough over the West Coast at about 85 kts. The rest of the primary storm track is over the North Pacific, well south of the mainland.

MODEL DISCUSSION. In general, the models are handling the overall synoptic pattern with good consistency. However, without a strong system to latch onto, they are struggling to resolve the finer details. Some of these finer details surround the bands of snow over the Northern Kenai and the Anchorage Bowl. The GFS continues to be the driest with this set up, but it remains the outlier. This forecast package will lean mostly towards the hi-res models and some hand edits, especially in handling this banded precipitation. Forecast confidence overall remains moderate.

AVIATION. PANC . IFR visibility will persist in snow through much of the forecast period. Ceilings will linger in the MVFR range, but could easily drop to IFR in heavier snow. The timing of when snow ends is highly uncertain. It certainly looks to become lighter as we go through the overnight hours which should allow ceilings and vis to come up some.

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3; Tonight through Thursday) .

The surface low just south of Whittier will slowly drift north through the evening. Light snow is expected to continue for portions of Southcentral as a trailing upper level trough lifts over the area. Another one to two inches of snow is possible from north of Kenai up across the Mat-Su Valleys. A mix of rain/snow is still possible through the overnight hours across parts of Prince William Sound as the southerly flow ahead of the low has ushered in enough warm air from the Gulf to push temperatures above the freezing mark. Temperatures will hold steady in the teens and twenties tonight and tomorrow for the Kenai Peninsula north to the Susitna Valley. For the Copper River Basin, temperatures will remain a few degrees on either side of 0F. Precipitation will slowly taper off overnight across the Kenai Peninsula and through Tuesday night elsewhere as the upper trough moves north beyond Southcentral. This will allow the flow aloft to turn northerly, ushering in a colder and drier air mass for the second half of the week. The northerly flow will also reestablish the gusty, northerly outflow winds through the passes and along the immediate coast by Thursday as arctic air spills south across Southcentral and temperatures plunge back to values we saw prior to this current storm.

SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2).

Snow showers along the Kuskokwim Delta coast will move farther inland and then taper off through the night as a front weakens over the area. Snow accumulations should be minimal with this system as it moves in towards Bethel for the early morning hours. With lingering moisture across the region, expect low level stratus and patchy fog to persist overnight and into the morning hours for Tuesday for the Kuskokwim Delta and even into interior Bristol Bay. Cold temperatures will remain across Southwest Alaska through the week as an Arctic air mass moves in from the northwest into the mainland on Tuesday. Cold temperatures will continue to move in through Thursday, when strong cold advection will bring northerly flow and gusty conditions to interior Bristol Bay and the Alaska Peninsula.

SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2).

Cold, unstable air persists across the Bering this afternoon, which will keep snow showers in the forecast through Tuesday. The Pribilof Islands will likely see snow showers continuing through the night, tapering off by the early morning hours.

Attention quickly shift towards the western Bering on Wednesday morning when a strong North Pacific low enters the forecast area. This system will cross over the Chain into the western and Central Bering by Wednesday afternoon, with precipitation quickly transitioning from snow to rain as warmer air moves in with this low. Expect high end gale force winds accompanying this system, with gust to storm force level as it moves over the Bering.

MARINE (Days 3 through 5: Thursday through Saturday).

Gulf of Alaska:

A low over the eastern Gulf Thursday will turn westward and move to near Middleton Island by Friday morning. The low will stall out and remain nearly stationary through Saturday morning, then dissipate or get absorbed into a new low moving into the eastern Gulf Saturday evening. This will keep gales ongoing continuously across the Barren Islands and through bays and passes southwest of Kodiak Island through Friday. The gales may weaken to small craft winds on Saturday, depending on where the low is at that point and where the next low moves into the eastern Gulf. Significant forecast uncertainty persists on Saturday.

Bering Sea and Aleutians:

A strong and nearly stationary low centered south of the western Aleutians will keep widespread gales with occasional embedded storms ongoing across the central and western Bering through Friday. Seas of 20 to 35 ft are expected over a large area of the central and western Bering and Aleutians through Friday night. By Saturday the low will move to near Kamchatka, which will result in gradually diminishing winds over the western Bering on Saturday. Strengthening high pressure over the eastern Bering will cause gale force offshore winds to develop Friday night through Saturday from the Southwest Alaska coast. The gales will extend south through the bays and passes of the Alaska Peninsula and eastern Aleutians by Saturday evening.

LONG TERM FORECAST (Days 3 through 7: Thursday through Monday).

The stagnant weather pattern intensifying on Thursday will persist through the weekend, and potentially last even longer. A strong and nearly stationary low centered south of the western Aleutians will keep gale force winds and rain ongoing across the central and western Aleutians through at least Friday night. On Saturday, the low moves off to the Kamchatka Peninsula, but another North Pacific low may move in to the same area to replace the old one into Monday. There is significant model uncertainty about where the new low tracks, however.

Meanwhile, across the eastern Bering and mainland Alaska, high pressure will strengthen with time through at least Saturday. After that there is some model disagreement as to how quickly the high pressure moves westward into the Bering. The GFS is much faster moving the high westward than the foreign models. Either way, the high will support increasingly cold air flooding southward on strong winds across Southwest Alaska, the eastern Bering, and the gaps and passes of Southcentral from Saturday through Monday. This will be a favorable pattern for another round of wind chill hazards in these same areas.

Across the Gulf, the weather will remain unsettled as a low over the eastern Gulf on Thursday moves to near Middleton Island on Friday morning, then parks itself there and spins moisture, very likely in the form of snow given the cold air around, into coastal areas. Since the low will be relatively weak and hardly moving, any snow that falls is not expected to become heavy, but it looks to persist in some areas through Saturday. There is considerable uncertainty on who gets what amount of snow and when, so stay tuned for future forecast updates. By Monday, with the high gradually drifting west over the Bering, the storm track may begin to shift westward along with it into the Gulf and Southcentral, which, if it occurs, would bring back more seasonably cold temperatures, and much greater threats for snow into Southcentral.

AFC WATCHES/WARNINGS/ADVISORIES. PUBLIC . NONE. MARINE . Heavy Freezing Spray 150 160 180 185. FIRE WEATHER . NONE.

SYNOPSIS AND MODEL DISCUSSION . MSO SOUTHCENTRAL ALASKA . CK/TM SOUTHWEST ALASKA/BERING SEA/ALEUTIANS . AH MARINE/LONG TERM . JW

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Weather Reporting Stations

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Stations	Dist	Age	Wind	Air Temp	Water Temp	Waves	Pressure	DewPt
CRVA2 - 9454050- Cordova, AK	22 mi	49 min		34°F	40°F		995.2 hPa
VDZA2 - 9454240 - Valdez, AK	72 mi	49 min		21°F	43°F		996.4 hPa
46061 - Seal Rocks 55NM South of Valdez, AK	77 mi	71 min	S 9.7 G 14	37°F	40°F	6 ft	994.2 hPa (+1.6)

Wind History for Cordova, AK

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Airport Reports

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Airport	Dist	Age	Wind kt	Visibility	Sky/Weather	Temp	DewPt	Humidity	Pressure
Cordova, Merle K (Mudhole) Smith Airport, AK	10 mi	68 min	Var 3	9.00 mi	Unknown Precip	34°F	32°F	92%	995.8 hPa

Link to 5 minute data for PACV

Wind History from ACV (wind in knots)

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Tide / Current Tables for Pete Dahl Slough, Alaska

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Tide / Current Tables for Eyak River entrance, Alaska

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Weather Map

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GEOS Local Image of PacificNorthwest    EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
Link to Loop

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Wind Forecast for (22,6,7,8)

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Ground Weather Radar Station Middleton Is., AK

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