textproduct: Fairbanks

SYNOPSIS

A Bering Sea low is continuing to move towards Norton Sound where it will weaken and stall around midweek. A warm front connected to this low is being ejected towards the Interior this morning bringing gusty winds, moderate to heavy rainfall, and cooler temperatures. Along the West Coast gusty southwesterly winds will bring higher water levels starting at the high tide later this afternoon. With the low slowly moving closer to Norton Sound, southerly gap winds are continuing to ramp up in the Alaska Range Passes. A High Wind Warning has been issued for these passes with gusts up to 70 mph possible through Wednesday morning. Widespread moderate to heavy rainfall will continue through Tuesday with the exception being the Eastern Interior and North Slope where downsloping will keep it drier. Through the rest of the work week expect isolated to scattered showers to continue, but warmer weather to make a return.

KEY WEATHER MESSAGES

Central and Eastern Interior... - Cooler temperatures across the Interior today as a Bering Sea storm brings cloud cover and rain showers. Temperatures will return to the mid 70s Tuesday afternoon.

- The leading edge of a warm front is beginning to move into the Central Interior this morning. Steadier rain is expected this morning before becoming more showery in the afternoon hours.

- Rainfall totals late Sunday through Tuesday are expected to be around 0.25-0.5" around FNSB, T-0.1" east of Fairbanks to the Alcan Border, 1.0-2.0" northwest of Fairbanks, and 0.5-1.5" in the Alaska Range west of the Tok Cutoff.

- High Wind Warnings and a Wind Advisory for southerly wind gusts have been issued for the Alaska Range passes and Delta Junction respectively. From Sunday night through Tuesday night, gusts could exceed 70 mph through the passes and 50 mph at Delta Junction. Wind gusts elsewhere across the Interior will peak on Monday around 20 to 30 mph.

West Coast and Western Interior... - A Bering Sea low is continuing to bring widespread gusty winds and moderate to heavy rainfall to the region. This low is peaking in intensity this mornings, and will begin to slowly weaken and stall.

- So far this storm has produced 0.5" to 1.25" of rainfall across the region. There will be a brief lull in precipitation as the current warm front moves east out of the region. Another front will bring an additional 0.5" to 1.5" of rainfall Monday night through Tuesday.

- Winds gusts will peak around 30 to 50 mph regionwide as the low moves in, with minor coastal impacts expected for communities along the West Coast. A High Surf Advisory has been issued for the YK Delta coast for these conditions.

North Slope and Brooks Range.. - Temperatures will be slightly cooler as a front moves through the region bringing rain. Daytime highs will be in the 60s/70s and will warm starting on Tuesday with highs in the low to mid 70s.

- With the approaching front there will be a round of rainfall today. North of the Brooks Range rainfall amounts will be light with a T-0.1" expected. In the Brooks Range however could see 0.25" to 0.75" of rainfall. The highest amounts will be the south facing slopes in the Central Brooks Range.

- After the front moves over the coastal communities later this afternoon, onshore flow will return bringing chances for fog and low stratus again Monday night.

FORECAST ANALYSIS AND DISCUSSION

Current satellite imagery this morning has the leading edge of the warm front moving through the Northern Interior. With the low center moving very close to St. Lawrence Island, we can use the Savoonga AWOS station to determine how well models initialized the low. Savoonga reported a sea level pressure of 985.5 millibars (mb). This puts it in line with almost all of the model guidance. This helps to build confidence on the wind forecast panning out over the next 24 to 48 hours. Most of the winds across the West Coast and Western Interior should have already peaked, but the strong winds in the Alaska Range and at Delta Junction are still strengthening. The pressure gradient along the Alaska Range should peak from 10 AM to 4 PM today with a gradient of 8 to 10 mbs. This will allow for us to see 70 mph winds in the passes and 55 mph at Delta Junction. While the pressure gradient slacks after 4 PM today, the low will bring a series of mountain waves through Tuesday night to help keep the winds elevated.

As the warm front continues to move northwards expect 0.5" to 1.25" of rainfall through this evening. Areas east of Fairbanks will remain fairly dry due to the strong chinook flow that is building. Behind this warm front will be a brief lull as drier air builds in behind it, however an upper- level trough is rotating through the Southern Bering Sea, and will bring an additional front overnight Monday and through Tuesday. This front could bring an additional 0.5" to 1.5" of rainfall. The highest amounts for the second round of precipitation will be in the Western Interior and along the West Coast.

As the low in the Bering moves into Norton Sound and then onto the West Coast Tuesday afternoon, it will weaken significantly and also begin to stall as high pressure is in the Bering Sea and Western Canada. With the low stalling we will have chances for isolated to scattered showers across the Interior through mid week. With enough cold air in the mid levels there could be enough instability for an isolated thunderstorm to accompany these rain showers in the Western Interior. While daily rain shower chances will continue through midweek, warmer temperatures will return for Northern Alaska Tuesday.

FIRE WEATHER

A large, very wet, low pressure system brings widespread wetting rains to the West Coast and the Western and Central Interior as well as gusty southerly winds across the West Coast, Western Interior, and over the Alaska Range. This low settles Monday over the Norton Sound area and slowly weakens in place through Thursday. The heaviest precipitation is expected Monday with steady rains expected to turn more showery late Tuesday into Wednesday. Rain showers remain over the West Coast and Western Interior through much of the rest of the week as the remnants of the low still linger over the West Coast. Gusty southerly winds across the West Coast/Western Interior in the 30 to 40 mph range are expected through early Tuesday. Funneling through the Alaska Range passes will allow even stronger winds with gusts up to 70 mph through those passes.

Areas just north of the Alaska Range in the southern portions of the Tanana Valley and much of the Fortymile Country will see significantly less rain as the large amount of southerly flow over the Alaska Range creates a dry layer that the rain would need to overcome first. Due to the presence of strong winds and lack of wetting rains these areas see the worst conditions early this week.

As the low weakens extremely isolated thunderstorms become possible across the Western Interior Tuesday, spreading into the Central Interior Wednesday, and farther east to cover much of the Interior by Thursday. Heavy rains from this system will leave the fuels in much of the Western and Central Interior quite damp, limiting the potential for new starts.

Temperatures for the week bottom out Monday due to the low and its rain. Temperatures are expected to slowly warm through the end of the week as the low weakens and conditions return more towards their seasonal norm.

HYDROLOGY

A low in the Bering Sea is continuing to move widespread moderate to heavy rainfall into the Western Interior and southern slopes of the Brooks Range. Over the past 24 hours there has been 0.5" to 1.25" of rainfall reported across the West Coast and Western Interior. An additional 0.5" to 1.5" of rainfall is expected over the next 24 to 36 hours. No flooding is currently expected, but river rises are anticipated and smaller creeks and streams could become bankfull.

EXTENDED FORECAST DAYS 4-7

THURSDAY THROUGH SUNDAY. Model guidance is in fairly good agreement in the first couple of days on the extended period. The low in the Bering Sea will have moved into the Western Interior and stalled. An approaching arctic trough Thursday night and Friday will help to move this low out of the region by Saturday. This arctic trough will bring some cooler temperatures and isolated to scattered rain showers to the North Slope Friday and Saturday.

Where the models begin to diverge is around Saturday night. In the Southern Bering Sea the north pacific high it attempting to build into the region. The GFS ensemble is very aggressive at building this ridge axis across the Interior, which would allow for most of the Interior to be warmer and drier. The ECMWF ensemble on the other hand keeps a weak low in Bristol Bay and strengthens the ridge over Western Canada. This solution would keep the West Coast cooler and wetter, but the eastern half of the Interior hotter and drier. There are a lot of little pieces moving through the overall pattern, so it is tough to pinpoint on one solution in particular.

Coastal Hazard Potential... Gusty southerly winds from a Bering Sea low will result in higher surf along the West Coast. Water will rise 1 to 3 feet above mean high tide, with the highest water peaking Monday afternoon during high tide. These higher waters will remain elevated even during the low tide overnight Monday, by the Tuesday afternoon high tide water levels will begin to decrease.

AFG WATCHES/WARNINGS/ADVISORIES

AK...High Wind Warning for AKZ849. Wind Advisory for AKZ829-830-852. Wind Advisory for AKZ837. High Surf Advisory for AKZ825. High Wind Warning for AKZ847. PK...Gale Warning for PKZ801. Small Craft Advisory for PKZ803>805-851>853. Small Craft Advisory for PKZ812-858.