textproduct: Fairbanks

SYNOPSIS

Isolated thunderstorm chances remain in place across much of the Interior and the Brooks Range. Storms will be more scattered along the Al-Can border and southern portions of the Western Interior. The combination of a pronounced shortwave and Bering Sea low will bring a swath of precipitation across the Interior, throughout the weekend, with totals between 0.5" and 1.5" possible. These heavy showers have a chance to cause a noticeable increase in water levels for a portion of the Interior, with a particular focus near Denali National Park. A cold front will gradually move NE across the state from the YK Delta starting Saturday. Ahead of the front, thunderstorm chances will continue. Behind the front, southwesterly winds are expected to increase across much of the Interior, lasting through the start of next week.

KEY WEATHER MESSAGES

Central and Eastern Interior... - Mid 70s to low 80s are expected tomorrow with another round of isolated thunderstorm

- Isolated to scattered storms will continue on Saturday out ahead of a cold front moving NE from the Upper Kuskokwim. High temperatures are expected to be cooler in the low 70s.

- Southwest flow behind the front will allow for showery conditions to continue into Sunday with highs in the low 60s. Widespread rainfall totals are expected to range between 0.5" to 1.0" across the Interior while the White Mountains could see totals in excess of 1.5" through Sunday night.

- Following the frontal passage Saturday afternoon, a noticeable increase in southwesterly winds is expected across the lower to central Tanana Valley. - Elevations above 2000ft will see winds between 30 and 40 mph. Some of these stronger winds will have a chance to mix down to the valleys throughout the weekend.

West Coast and Western Interior... - Isolated to scattered thunderstorms expected across the southern portions of the Western Interior today. Some storms could last into the late evening hours, similarly to the previous night.

- Northerly winds will gradually increase throughout the weekend along the Bering Strait and NW Arctic coast as lower pressure moves across the state. An uptick in west/southwest winds expected across the Western Interior and Norton Sound coast with the cold front passage on Saturday.

- A cooling trend arrives this weekend with a fall-like feel expected as highs remain in the 50s and 60s by Sunday. Heavy rain is possible towards the western AK Range on Sunday, this may spread into the Kuskokwim Valley and will be monitored.

North Slope and Brooks Range.. - With the recent cold front passage, expect highs in the low to mid 30s along the Western Arctic Coast, upper 30s/low 40s east, and 50s/60s in the Brooks Range.

- Winds turn northeast with speeds around 5 to 15 mph with higher gusts making it feel quite chilly for late June.

- Thunderstorm chances continue along the south slopes and eastern portions of the Brooks Range today with the remnants of the stationary front moving overhead.

FORECAST ANALYSIS AND DISCUSSION

Some isolated storms continued, into the early hours this morning, on the northern side of the stationary front that set up from the Upper Kuskokwim to the Northern Interior. Remnants from this front will continue to linger over the Brooks Range today, allow thunderstorm chances to continue through the afternoon. Meanwhile, a 535 decameter Bering Sea low will continue to spin west of St. Paul Island through the early morning. Another low continues to work its way SE along the Alaska Panhandle while ridging builds up over NW Canada. Some of the energy from low will get caught up in the flow, in the northern gulf, and move north along the Al-Can border. This shortwave will continue to provide chances for thunderstorms today across the Interior today, with elevated chances over the SW Interior and AL-Can border. The bulk of the energy from the shortwave will work its way over the Central/Eastern Interior Saturday afternoon as the low in the Bering shifts east toward Bristol Bay. A SW/NE oriented cold front will slowly begin to work its way NE from the YK Delta by the late weekend, which will bring a slight pattern shift to the start of the week. This will also keep thunderstorm chances limited to the Central and Eastern Interior on Saturday.

A decent swath of moisture is expected to accompany this shortwave and frontal system with will provide chances for wetting rain across the Interior through the late weekend. Widespread rainfall totals are expected to range between 0.5" to 1.0" across the Interior while the White Mountains could see totals in excess of 1.5" through Sunday night. Exact totals could change over the next day as ensembles continue to show a large spread in QPF. Behind this cold front, southwesterly flow will set up across much of southern Alaska, allowing scattered showers to continue. This front will also bring an uptick in winds as an associated surface low moves NE from the YK Delta. In addition, models are showing the potential for a low-level jet to set up across the lower Tanana Valley, with the frontal passage, which will see the greatest chances for gusty winds Saturday night into Sunday. With this, gusts could reach as high as 40 mph into the valleys. By Sunday evening, the low will work its way over the YK Delta, allowing the new area of broad troughing to continue into the start of the week for much of northern Alaska.

FIRE WEATHER

Ridging across the Interior will continue today bringing another warm day for most. Temperatures will continue to rise into the 70s and low 80s across the Interior Valleys. The main areas of concern for relative humidity will be the Kobuk and Lower Koyukuk Valleys with RHs in the upper 20s. Winds are not expected to be a concern until Saturday when a Bering Sea low begins to move into the Interior. Today will see more isolated to scattered thunderstorms from the Kuskokwim Mountains and east to the Al-Can border and then north to the Brooks Range. The area with the best chance to see scattered thunderstorms will be the AlCan border and the Kuskokwim Mountains.

Saturday will see a major pattern shift as a low in the Bering Sea moves towards the Interior. This low will bring a cold front swinging south to north across the Interior bringing widespread wetting rains. From the Alaska Range to the White Mountains we could see rainfall totals of 0.75" to 1.25". The higher totals will be focused in the terrain while the valleys could see higher amounts, there is less confidence in that to occur. Wetting rains are expected to continue through the weekend with them becoming more showery on Sunday afternoon. By Monday expect isolated showers as well as cooler temperatures.

HYDROLOGY

No update from previous version A long-duration period of moderate rain is anticipated to start on Saturday evening and continue through Monday. This could impact a large portion of the Interior with a particular focus near Denali National Park.

Return intervals indicate this as a 1 in 5 year to a 1 in 10 year event. We are continuing to monitor and will provide updates on the evolution of this system.

Those recreating on or near rivers should expect water level increases late in the weekend and into early next week. A hydrologic outlook remains in place through Monday.

For more information visit: weather.gov/afg/?story=5

EXTENDED FORECAST DAYS 4-7

The Bering Sea low will begin to move east into the YK-Delta on Sunday, settling over the South Central Interior on Monday, and begin to move Eastward towards Canada by Wednesday. A cold front brought on by the closed low, will begin in the Southern Interior of Alaska on Saturday directly before the closed low reaches the YK- Delta. The frontal system will move Northward to the Brooks Range by Sunday and weakening soon after, continuing the ongoing precipitation within our region. Heavier showers and thunderstorms are expected for the Eastern and Central Interior with the intensity decreasing as the front passes through. Gusty winds are expected for areas of higher terrain within the Interior Saturday to Sunday, as the closed low in the Bering Sea will create a significant pressure gradient with the remnants of the ridge along the North Slope. As ridge deformation occurs and low pressure overtakes our area it is expected that these gusty winds decrease leading into Sunday evening. Temperatures are expected to approach below normal as the cold front is followed by a cooler air mass.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...None. PK...Small Craft Advisory for PKZ806-854. Small Craft Advisory for PKZ807-856. Brisk Wind Advisory for PKZ810. Small Craft Advisory for PKZ811.