textproduct: Fairbanks

SYNOPSIS

A low pressure in the Gulf of Alaska tapping moisture from the tropics is expected to bring rain showers for much of the state towards the end of this weekend and into next week. Highest rainfall totals are expected in the Brooks Range where some areas could see 1" or more. Today, Delta Junction and the Yukon Flats are expected to have fire weather concerns with gusty winds and dry conditions this afternoon. Coastal areas along the West Coast and North Slope continue to experience fog that is expected to continue through the weekend. Elsewhere, the warmest conditions so far this season are expected to continue today, with some areas in the Interior possibly seeing 80F, especially the Yukon Flats.

KEY WEATHER MESSAGES

Central and Eastern Interior... - Red Flag Warning for Delta Junction and Isabel Pass this afternoon. South winds gusting up to 60 mph and RH values as low as 30%.

- Red Flag Warning for the Yukon Flats this afternoon with RH values as low as 20% and south/southeast winds up to 15 mph and gusts up to 25 mph.

- Wind Advisory for Isabel Pass this afternoon and evening for south winds 30 to 40 mph with gusts up to 60 mph.

- The warmest temperatures of the summer so far with temperatures approaching 80F are occurring under mostly sunny skies primarily for the northern Interior today.

- Breezy conditions are expected Sunday through Tuesday with easterly winds on Sunday and southwesterly winds on Monday and Tuesday as a storm system lifts north across the Interior. This system also brings widespread clouds on Sunday followed by rain chances Sunday night into Monday morning in addition to cooler temperatures.

West Coast and Western Interior... - Areas of low stratus and fog are expected to persist through the weekend across St. Lawrence Island and portions of the Norton Sound coastline.

- Highs mainly around 70F with the warmest Interior valleys approaching 80F and the coolest coastal spots staying around 60F. Highs mainly in the 40s and 50s on St. Lawrence Island.

- A frontal boundary stalls roughly between Marshall and Ambler from Sunday through Tuesday focusing scattered showers and a few embedded afternoon thunderstorms and around 0.25" of rain with locally higher amounts possible in thunderstorms.

North Slope and Brooks Range.. - Seasonably mild on the Arctic Coast with highs in the 30s and 40s through the weekend. Warmer in the Plains and Brooks Range with highs in the 60s and even 70s.

- Moderate to locally heavy rainfall for the central and portions of the eastern Brooks Range and adjacent portions of the North Slope between Monday and Tuesday. Two day rainfall amounts of at least 0.5" are likely and a narrow band of heavier rainfall of 1" or more is possible. The exact placement of the heaviest rain is uncertain, but Anaktuvuk Pass north to Deadhorse seems most likely to achieve those higher totals.

- The combination of snowmelt and rainfall is expected to result in rising river levels early next week, but rivers are mostly ice free so ice jams are not expected at this time.

FORECAST ANALYSIS AND DISCUSSION

Upper-level troughing is expected to dig into the state today, bringing one more day of relatively warm weather to northern portions of the Interior while the West Coast and southern Interior are expected to be a little cooler with clouds and rain showers. As the low moves shortwave energy moves northward over the state, embedded thunderstorms are possible, especially from the YK Delta northward towards the Brooks Range. This low is also tapping moisture from the tropics, intensifying rainfall totals. Areas along the West Coast could see totals as high as 0.25" with locally higher amounts possible with thunderstorms. The Brooks Range and Deadhorse are expected to receive the most amount of precipitation with this system with totals as high as 1" or more in some areas by Tuesday evening. These high rainfall amounts are expected to result in rivers rising, though ice jams are not expected due to ice already moving out of the North Slope rivers. As this energy moves northward gusty winds will be likely for northern Alaska, prompting a Wind Advisory for Isabel Pass for this afternoon and evening. With gusty winds, low RHs, and high temperatures near 80F, fire weather conditions are possible today for the Yukon Flats. RHs near 30% and gusty southerly winds as high as 60 mph will also lead to fire weather concerns for Delta Junction today.

By Tuesday afternoon, the upper-level troughing over state starts to become upper-level ridging, leading to temperatures to rise again and isolated afternoon showers and thunderstorms. More about this in the Extended Forecast section.

FIRE WEATHER

Tomorrow looks to be the most active fire weather day in the short term, with a new Red Flag Warning in effect for the Yukon Flats. Localized areas of the Yukon Flats will see temperatures above 80F, minimum relative humidities between 20 and 25 percent, and south/southeasterly winds up to 15 mph. Stronger wind gusts are possible in the afternoon and evening. Sunday will also be the second day of Red Flag Warnings for Isabel Pass and Delta Junction. While the aspect contributing most to yesteday's red flag conditions were dry conditions, the primary concern with today's fire weather conditions will be gusty southerly winds up to 55 mph. These winds are expected to weaken by Sunday evening, with periods of gusty winds up to 20 mph possible across higher elevations of the Interior through midweek. Isolated wet thunderstorms are possible this afternoon for a portion of the state extending from the southwest coast around Mountain Village up through the southwestern/southcentral slopes of the Brooks Range. Additional scattered showers are likely across the Western Interior and Brooks Range through Wednesday as anomalously high amounts of moisture are advected in the area by a low in the Gulf of Alaska. Looking ahead, overall thunderstorm activity is expected to remain fairly quiet through Tuesday with very isolated to isolated thunderstorms returning to the Interior by the second half of the week. High temperatures are expected to remain at or below 70F before warming up again into the low to mid 70s by Thursday afternoon as ridging builds back in over the state. As a more summer-like pattern settles in late next week, a trend towards more near critical fire weather days is possible.

HYDROLOGY

Most of the North Slope Rivers have broken up with little to no impacts. Moving forward as summer arrives and temperatures rise, there is a potential for snowmelt relative river stage rises. Temperatures stay mostly above freezing tonight and warm substantially on Sunday, perhaps above 60F in spots due to downsloping off the Brooks Range. Rain chances increase late on Sunday and may include a few embedded evening thunderstorms before transitioning to steady stratiform rain Sunday night into Monday night. Moderate rainfall amounts around 0.5" are likely across the central Brooks Range and adjacent North Slope foothills where most of the remaining snowpack is located. Locally higher amounts in excess of 1" are possible (~50% chance) between Sunday evening and Tuesday afternoon. This could lead to rapid melt and rising river levels due to the combination of rainfall and snowmelt. This contrasts with last year's late breakup when the snowmelt all entered the river systems while ice was mainly still in place.

Rising of water levels in rivers can be expected late this weekend or early next week.

EXTENDED FORECAST DAYS 4-7

Wednesday through Saturday. After an unsettled beginning to the week, model guidance supports a ridge building over Southeast Alaska starting on Wednesday. There is still uncertainty in this ridge's strength and extent over the state, as well as the strength and location any disturbances in the vicinity of the ridge. As the ridge builds, temperatures will return to seasonable norms, but embedded disturbances will keep the potential for scattered showers across the state. Thunderstorm activity is possible on Wednesday and Thursday, but model guidance indicates increasing chances for afternoon and evening thunderstorms on Friday and Saturday. Typical summer conditions might be sticking around for more than a few days this time around, which is fitting given that the solstice is a week from today.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Wind Advisory for AKZ849. Red Flag Warning for AKZ933. Red Flag Warning for AKZ937. PK...Small Craft Advisory for PKZ801-850. Small Craft Advisory for PKZ806. Brisk Wind Advisory for PKZ814-860. Brisk Wind Advisory for PKZ815. Brisk Wind Advisory for PKZ861.