Area Forecast Discussion
Issued by NWS Fairbanks, AK
Issued by NWS Fairbanks, AK
171 FXAK69 PAFG 290933 AFDAFG Northern Alaska Forecast Discussion National Weather Service Fairbanks AK 133 AM AKDT Wed May 29 2024 .SYNOPSIS... More summer-like weather returns to the Mainland as we head into the weekend, with chances for Interior thunderstorms and heavier rain showers, along with warmer temps. Today will be an active weather day for the entire S Interior as heavy showers and an isolated thunderstorm will be possible by late afternoon. Recent heavy rains over the E Alaska Range and SE Interior will shift westward and come to an end for the time being. && .DISCUSSION... Upper Levels and Analysis... Weak ridging has built over the Mainland with a 555 dam ridge now in place with that center over the E Brooks Range, but extending south to include the entire Mainland. There is a departing 526 dam arctic low over the Chukotsk Peninsula, with another departing Gulf of AK low, with that center now analyzed around 549 dam. There is a 531 dam low over the E Aleutians. A weak shortwave trough, an easterly wave, is moving west over the S Yukon Terr. Model Discussion... The models are in much better agreement for the next few days with only minor discrepancy expected with summer-time convective season. There will be daily chances for showers and thunderstorms so a blend of models is favored, as small ripples of energy move through the flow. This is normal for an easterly flow pattern. We will favor the hi-res models for winds and a blend of the GFS and ECMWF for the general details. Central and Eastern Interior... Fairly nice day today with warming temps to near 70 over much of the Interior, then an increasing chance for isolated to widely scattered thunderstorms in the afternoon, initiating over the higher terrain east of the Tanana Valley and then moving west during the late afternoon and evening. Some showers will be rather heavy and may produce heavy rainfall across the S Interior into the overnight hours. Thursday will be 5 or so degrees cooler across the S Interior as south winds push through the Alaska Range gaps, bringing cooler and more moist marine air inland. Showers and isolated thunderstorm chances mainly move north of the White Mtns to the Yukon Flats and Upper Koyukuk Valley. Friday warms back up into the lower 70s with chances for showers and an isolated thunderstorm, focused over the E Interior and higher terrain. West Coast and Western Interior... Warming temps today with values approaching 70 over the Interior and 60s over parts of the Seward Pen. Showers and isolated thunderstorms are likely late this afternoon over the Kuskokwim Valley and into the Lower Yukon. Some stronger showers and storms may push out toward the Delta and to the coast. Showers and thunderstorm chances continue on Thursday and will move north including the N Interior and Seward Peninsula, which may even see a thunderstorm or two given the easterly flow aloft. Friday looks less active, but there will still be an isolated thunderstorm threat over the Interior to the S Brooks Range, but temps will be a few degrees cooler. North Slope and Brooks Range... Clouds have briefly cleared out over the Arctic as a weak high as allowed for winds over the immediate coast to switch from onshore to offshore. Later today and tonight the high builds offshore which means the low level winds switch back around to northeast, so expect more widespread stratus and fog to move back in, and eventually shift all the way down to the slopes of the Brooks Range. Winds over the W Arctic increase to 25 to 35 mph tonight through Friday from the northeast. Extended Forecast Days 4-7... The suite of global models and their ensembles are beginning to show a clearer picture of the pattern after Friday, with a large low over the Gulf of AK and weak Interior ridging building in slightly from the Yukon, along with another arctic trough digging into the NW Arctic and then down the West Coast as we head into the next week. This pattern looks to bring warming temps to Interior Alaska with widespread values above seasonal norms by Saturday or Sunday. It also looks more active for thunderstorm chances. Out west, it looks like a return to north winds and slightly cooler temps, but otherwise probably on the sunnier side. Coastal Hazard Potential Days 3 and 4...None. && .FIRE WEATHER... Isolated to widely scattered wet thunderstorms are expected today as an easterly wave moves across the E Interior and across the S Interior. The best chance for thunderstorms will generally remain over the higher elevations east of the Tanana Valley, with heavier rain showers as they move into the valley. Any storms will be very wet. Early afternoon temps will push into the 70s before clouds and showers drop those values. Out west, a secondary thermal trough will spark of isolated wet thunderstorms over the Kusko Valley to the Lower Yukon. It too will be warmer today before cooling tomorrow as the thermal trough lifts north toward the Middle Yukon Valley to the Yukon Flats. Expect the S Interior to be cooler Thu before warming back up Fri. By this weekend, it looks to be warming above seasonal norms for the Interior for several days, along with increased chances for thunderstorms. && .HYDROLOGY... The water level in Fort Yukon will crest the mid-week. Minor flooding will continue through at least the middle of the week, with water receding very slowly by late in the week. Satellites and ground observations continue to indicate abundant snow in the Porcupine Mountains. As temperatures warm this week, snowmelt could lead to continued high water along the Porcupine and the interrelated sloughs. Rainfall has resulted in some minor stream flooding in the E Alaska Range where 1 to 2 inches of rainfall has fallen along with higher elevation snow. A flood advisory is out for the E Alaska Range from just east of the Richardson Highway to north and east of Mentasta Pass. With less rainfall projected in the next 72 hours, water levels should come down. There are no significant hydro concerns for now for the larger stem rivers as they remain low. && .AFG WATCHES/WARNINGS/ADVISORIES... AK...Flood Warning AKZ833 PK...Small Craft Advisory for PKZ806. Brisk Wind Advisory for PKZ807. Small Craft Advisory for PKZ816-817. Small Craft Advisory for PKZ851. Small Craft Advisory for PKZ854. Brisk Wind Advisory for PKZ856. && $$ Ahsenmacher