textproduct: Fairbanks

SYNOPSIS

Warm temperatures are expected across Alaska north of the Alaska Range this afternoon and evening. As a coastal system moves into the West Coast, cooler conditions with widespread minor rises in coastal water levels, heavy rain, and gusty southerly winds are expected across Western Alaska beginning Sunday. Temperatures will remain warm in the Central/Eastern Interior but will cool by a few degrees Monday as rain spreads east. Southerly downsloping winds across the Alaska Range will yield strong gusts through the AK Range passes and at Delta Junction while also helping to keep the Eastern Interior a bit drier. These areas will nonetheless have potential for light rain through Tuesday morning. Thereafter, while rain will likely continue in much of the area, it will likely be of a more showery nature, with warmer temperatures likely across the area.

KEY WEATHER MESSAGES

Central and Eastern Interior...

- Warm and dry conditions will continue across much of the Interior through the weekend with plenty of sunshine. Highs will remain in the 70s to low 80s with lows in the 40s/50s.

- Isolated rain showers will be possible late this evening into Sunday as a weak front tracks east over the Interior, but conditions are expected to remain predominantly dry.

- As a low from the Bering Sea tracks east Sunday into Monday, widespread rain and gusty winds will shift east across the Interior and Alaska Range. The bulk of precipitation is expected west of Fairbanks and in the Alaska Range, with driest conditions along the Alcan Border and Upper Tanana Valley.

- Rainfall totals late Sunday through Tuesday are expected to be around 0.10-0.25" around FNSB, T-0.10" east of Fairbanks to the Alcan Border, 0.50-1.50" northwest of Fairbanks, and 0.50-1.50" 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 at Delta Junction. Wind gusts elsewhere across the Interior will peak on Monday around 20 to 30 mph.

- As the Bering Sea low gradually weakens midweek, isolated to scattered rain showers will continue with temperatures that briefly cooled earlier in the week holding steady or seeing a warming trend to finish out the week.

West Coast and Western Interior...

- Warm and mostly dry conditions will continue across much of western Alaska through tonight, with isolated rain showers possible. Highs will be in the 60s to low 70s with lows in the 40s/50s, locally cooler along the West Coast.

- As a low in the Bering Sea tracks east Sunday into Monday, widespread rain and gusty winds will shift east across western Alaska. Steadier rain will reach St. Lawrence Island around midnight Sunday morning and the West Coast throughout the day Sunday.

- Rainfall totals Sunday through Tuesday are expected to be around 0.50-1.50" regionwide, with locally higher totals up to around 2.00".

- Winds gusts will peak around 30 to 50 mph regionwide as the low moves in, with minor coastal impacts expected (primarily high surf) for communities along the West Coast.

- As the Bering Sea low gradually weakens midweek, isolated to scattered rain showers will continue with temperatures that briefly cooled earlier in the week holding steady or seeing a warming trend to finish out the week.

North Slope and Brooks Range...

- Isolated to scattered rain showers build in through the weekend out of the west. Highs will be in the 60s to low 70s with lows in the 40s/50s, locally cooler along the Arctic Coast. - While rainfall totals through the weekend are expected to remain light overall, steadier rain will move into the Brooks Range on Monday as moisture from a low in the Bering Sea tracks north.

- Rainfall totals Monday and Tuesday will be heaviest in central and eastern portions of the Brooks Range, where around 0.50-2.0" of rain is expected, focused on the southern slopes, as the North Slope gets downsloped and stays predominantly dry.

- As the Bering Sea low gradually weakens midweek, isolated to scattered rain showers will continue with temperatures that briefly cooled earlier in the week holding steady or seeing a warming trend to finish out the week.

FORECAST ANALYSIS AND DISCUSSION

A 573 dm ridge is in place over the southern Alaska Mainland, with generally southwesterly flow on its northern flank and a developing low over the western Bering Sea. This flow will help to draw robust moisture well inland across Western Alaska as the low moves into the northern Bering moving into Sunday and Monday. Some of this moisture will have tropical origins from well to the south of the Aleutians. Before this cool, moist air mass moves in, warm temperatures are expected this afternoon across the Interior under the ridge, with highs rising into the 70s across the areas, with southern Interior valleys potentially rising into the 80s in spots. Some isolated thunderstorms will be possible over the eastern border and in the Brooks Range today and Sunday where some slight instability will combine with clear skies. By Sunday afternoon, as rain and cloud cover overspreads Western Alaska (which will begin Sunday morning), highs will drop into the 50s and 60s across Western Alaska while remaining warm in the Central and Eastern Interior.

The rain shield should overspread the Western and Central Interior by mid-to-late Monday morning, with these areas broadly seeing 0.5 to 2 inches of rainfall through Tuesday. This will coincide with southerly winds across Western Alaska, with widespread maximum wind gusts of 30 to 50 mph. The highest wind gusts are likely over the YK Delta, where gusts could locally exceed 50 mph. Southerly downsloping flow will increase across the Alaska Range during this same time frame, which will lead to strong gap winds through Isabel and Windy Passes. Wind gusts through the passes could exceed 70 mph, for which High Wind Warnings have been issued. Windy conditions with gusts up to 55 mph are also expected at Delta Junction, for which a Wind Advisory has been issued. This general southerly downsloping flow will result in drier conditions from around Fairbanks and east, although rainfall of up to about a quarter of an inch is still possible in the vicinity, with very light precipitation to the east. From Tuesday onward, while rain will likely continue across much of Western Alaska with the low meandering around in Western Alaska, it will likely be of a more showery nature as compared to the initial large area of persistent rainfall.

FIRE WEATHER

This brief stretch of hot and dry weather in the Interior has allowed for a slight bump in fire behavior. As a result, we are seeing haze in parts of the Interior where fires have managed to hold on. Favorable fire weather conditions will continue Saturday afternoon and Sunday. Expect temperatures to peak near 80F for most of the Interior Valleys Saturday afternoon with relative humidity in the low 30s/upper 20s for the southern Interior. A few isolated thunderstorms may develop in the central Brooks Range and North Slope Saturday evening, with the help of an upper-level shortwave moving over the area.

Sunday, the hottest and driest area will be in the Upper Tanana Valley and Fortymile country, again near 80F with RH around 25 to 30 percent. Temperatures will range from the mid 70s in the Central Interior to 60s in the Western Interior. Isolated thunderstorms may develop in the eastern Interior.

A particularly wet air mass arrives from the southwest on Sunday morning. This system will bring more than an inch of rain to a large portion of the western half of Alaska through Tuesday. Lighter rain amounts will make their way into the Interior, however the Eastern Interior from the Yukon Flats to the Upper Tanana Valley will stay drier, receiving less than a tenth of an inch if anything. In addition to the rain, the low will bring strong southerly winds to the West Coast, Western Interior, and Alaska Range. Winds in the western regions will be matched with rain, but strong southerly winds through Alaska Range Passes will keep the Tanana Valley drier. Winds are expected to peak Monday, with gap winds through Isabel and Windy blowing 30 to 50 mph and gusting up to 70. The southerly flow will also include the Brooks Range, leading to temperatures above 70F on the Arctic Plains by Monday and 60s near the Arctic Coast.

HYDROLOGY

As a coastal weather system moves from the Bering Sea across the Alaska Mainland, widespread rain of 0.5 to 2 inches are expected in Western Alaska. Similar rainfall totals will be possible in the Alaska Range west of the Tok Cutoff and in the Central Interior/Central Brooks Range. Rain totals could be locally higher, mostly in the higher terrain. While no flooding is currently expected, this will lead to rises on area rivers.

EXTENDED FORECAST DAYS 4-7

At the start of the extended forecast, the Bering Sea storm sitting over Western Alaska continues to provide ample energy and moisture to support widespread showers and gusty winds across Northern Alaska. Further inland, winds through the Alaska Range Passes are expected to gust upwards of 70 to 80 mph through Tuesday before gradually weakening going into Wednesday morning. As the Bering Sea storm gradually weakens on Wednesday, widespread rain transitions into scattered rain showers, with lighter rainfall accumulations expected across the Western Interior and YK Delta. Out east, a building upper level ridge over the Canadian Yukon works to keep much of the Central/Eastern Interior warm and dry through the latter half of the week. Model guidance starts to diverge looking towards Thursday in regards to where the Bering Sea low ends up. Right now, models are hinting at ridging building to the east and west of the weakening low pressure system, pushing the low farther south/southeast towards Southcentral Alaska. The exact timing of this shift is a bit uncertain right now, but seems to support a few lingering isolated rain showers and cooler temperatures out west, with warming and drying conditions over the Central/Eastern Interior going into next weekend.

Coastal Hazard Potential Days 3 and 4... As a low moves into the Northern Bering Sea and then into Western Alaska, strong southerly winds will result in minor high surf in coastal areas of Western Alaska. Water rises of 1 to 3 feet above mean higher high water will be common along the West Coast, which could lead to minor coastal erosion.

AFG WATCHES/WARNINGS/ADVISORIES

AK...High Wind Watch for AKZ837-849. High Wind Watch for AKZ847. PK...Small Craft Advisory for PKZ811.