textproduct: Fairbanks

KEY MESSAGES

Central and Eastern Interior...

- Warm conditions persist through the weekend, with widespread valley high temperatures reaching into the 70s to mid 80s. Slightly cooler temperatures Friday. Warming again on Saturday and Sunday, with highs reaching the mid 70s to lower 80s.

- Drier weather generally lasts until chances of more widespread showers return beginning early next week. Some isolated thunderstorms are expected for areas from the White Mountains on South on Saturday.

- Southerly gap winds increase through the Eastern Alaska Range Sunday into Monday as a low pressure system approaches from the southwest. This system ushers in cooler temperatures and more widespread rainfall early next week.

West Coast and Western Interior...

- Warm temperatures continue through the weekend, with inland highs reaching the mid to upper 70s and coastal areas in the 60s to near 70. A Heat Advisory is in effect from noon to 7 PM AKDT Saturday for the Noatak and Lower Kobuk Valleys and Seward Peninsula for temperatures reaching 75 to 80 degrees.

- Dry conditions prevail into Saturday. Isolated thunderstorms are possible in the Kuskokwim Delta area Saturday afternoon. Substantial moisture brings moderate to heavy rainfall potential to the southwest coast and inland areas Sunday night into Monday.

- The overall pattern shifts Monday as a low pressure system moves inland, cooling temperatures and bringing elevated precipitation chances through midweek.

North Slope and Brooks Range...

- Warm weather continues across the Brooks Range and Central North Slope through the weekend. Expect highs in the 60s and 70s, approaching 80 near Umiat. Easterly onshore winds keep the Eastern Arctic Coast cooler, with highs in the 50s.

- Shower and thunderstorm activity shifts into the Eastern North Slope and Brooks Range Friday evening before drier conditions return Saturday. Chances of rain return by Tuesday.

SYNOPSIS

Warm summertime weather over the weekend will prove to be short-lived, as a cooler and wetter weather pattern sets up by early next week. Through the first half of the weekend, a ridge overhead will bring temperatures in the 70s and even the lower 80s across much of northern AK, with the warmest temperatures for the eastern interior as well as areas closer to the Alaska Range. On Sunday, the pattern will begin to change, as a low brings widespread back across the western half of the state. While drier and warmer weather will linger for parts of the central and eastern interior a little longer, these will wind down by Monday as a front traverses up from the south and crosses the Alaska Range. Alongside the rain, some gusty winds are expected for various mountain passes late Sunday through Monday. The cooler and more rain-filled pattern looks set to remain through at least next week, and potentially next weekend.

SHORT TERM /THROUGH SUNDAY NIGHT/

Dry and warm weather will be in full force across northern AK through much of the weekend. As of the time of writing, a 576 decameter ridge is still holding steady across the interior of Alaska, deflecting the strongest of systems away from us, and bringing more clearing to parts of the state. 850 mb temperatures through the weekend will reach 11-14C across much of the interior, reflecting surface high temperatures which will reach into the mid to upper 70s, and for some locations even the lower 80s. The warmest temperatures will be focused around the central and eastern interior, along with areas adjacent to the Alaska Range, though the western interior and parts of the north slope still look set to climb into the 70s. A new shortwave rotating around the periphery of the ridge will bring chances of isolated thunderstorms to southern half of the western interior (south of the Seward Peninsula), and for the White Mountains south for the central and eastern interior.

On Sunday, the overall pattern undergoes a significant change, heralding cooler and wetter conditions for northern AK as we head into the second half of August. Aloft, the ridge which has been shielding the interior from the bulk of the Pacific storm track will be pushed E into the Yukon and then into Nunavut through Monday. The initial culprit - a strong shortwave rotating up into the Kuskokwim Delta around a stronger low on Saturday, will be swiftly replaced by the stronger low itself Sunday into Monday. This stronger low will fully dislodge the already weakened ridge, and send a stream of moisture northward for the western Interior, along with an organized front which will traverse the Alaska Range and bring growing chances of rain and wind for the Central and Eastern interior by Sunday night and into Sunday morning. Gusty winds are also expected for the time frame. Around 0.5 to 1.5 inches of rain are expected for the western interior through Tuesday, with lower totals for areas further north and east. For additional information, see the long term forecast discussion.

LONG TERM /MONDAY THROUGH FRIDAY/...Monday through Thursday

Cooler and wetter weather with general troughing aloft will characterize the extended time frame, with highs broadly falling below 70 degrees from Tuesday onward. On Monday, a low in the eastern Bering will help support southerly flow across the Alaska Range to continue through Tuesday morning, with gusty winds over 50 mph possible through Isabel Pass at times. Northerly winds will be possible through the Bering Strait during this same time frame. Rain will be likely Monday across Western Alaska as well as in the Alaska and Brooks Ranges, with the wettest spots (likely in the western Brooks Range and southwestern Interior) possibly seeing over an inch of accumulation. This precipitation will gradually shift east over the next two days while becoming more scattered. By mid/late week, heavier rain will be less likely, but periods of showers will remain possible across the Interior and North Slope.

Coastal Hazard Potential... No coastal hazard concerns are expected.

FIRE WEATHER

Two distinct weather patterns look set to impact the forecast going forward. Through the first half of the weekend, dry weather is pre-eminent, with high temperatures reaching into the 70s and even the lower 80s. Areas further east and further south will broadly be warmer than areas along the coast or the North Slope. Relative humidities will be down to 25 to 35 percent across the central and eastern interior on Saturday, although winds remain generally on the lighter side. A new shortwave moving up into the Kuskokwim Delta will create an arc of conditions favorable for isolated thunderstorm development across parts of the Western interior south of the Seward Peninsula all the way through the Eastern interior.

On Sunday, the situation begins rapidly changing. A low moving into the southwestern interior brings with it a surge of moisture and more widespread rain. Simultaneously, a front wrapping around the low's eastern flank begins to work its way up through the interior. A tightening pressure gradient ahead of the front will see winds strengthen cross downsloped areas of the Alaska Range - with the potential for a period of gusty winds and still lingering drier weather possible for Sunday for the eastern interior, ahead of the advancing front. On Monday, rainfall will overrun the rest of the state, including the eastern and central interior, with chances reaching as far north as parts of the north slope.

HYDROLOGY

Rainfall from late Sunday into Tuesday across the Kuskokwim Delta and the Western interior will result in some river rises, as 0.5-2 inches fall. No flooding is expected.

AFG WATCHES/WARNINGS/ADVISORIES

AK...Heat Advisory from noon to 7 PM AKDT Saturday for AKZ814-816- 818-823. MARINE...Small Craft Advisory from 7 PM this evening to 4 AM AKDT Saturday for PKZ857. Small Craft Advisory from 1 AM to 4 AM AKDT Saturday for PKZ858.