Area Forecast Discussion
Issued by NWS Juneau, AK
Issued by NWS Juneau, AK
400 FXAK67 PAJK 041339 AFDAJK Southeast Alaska Forecast Discussion National Weather Service Juneau AK 539 AM AKDT Sat May 4 2024 .SHORT TERM...Satellite imagery and surface analysis show a weak front pushing into the NE gulf coast with the parent low still W of AK peninsula. Models remain in good agreement with precip chances increasing N to S through the day. Expect precip to start over the NE gulf late this morning/early afternoon and spread E and S overnight into Sunday. Changes to the forecast were to adjust mass fields to current observations. .LONG TERM...An active weather pattern returns in full swing to SE AK as system after system moves into the panhandle, with each one bringing concurrent chances of rain and wind across the area. Aloft, the upper level pattern will sharply depart from its previous state of the past few weeks. The primary steering flow which was directing systems to the south and away from the panhandle will move directly overhead as a strong jet streak developing along the E flank of a deepening trough over the Bering Sea moves the primary area of upper level support over the panhandle. Closer to the surface, this will enable multiple waves to develop and enter the panhandle. The first wave, on Sunday, will be associated with an occluding system moving out of the NW which will cross the Gulf and dissipate over the panhandle, but not before bringing with it a return to more abundant precipitation. For more information on this system, refer to the short term forecast discussion. Lingering chances of precipitation associated with onshore flow will remain through Tuesday before another, stronger system arrives later on Tuesday or Wednesday. This second system will move up from the SW, moving around the broader area of upper level troughing. Expect a surge of more widespread precipitation to be possible with this system alongside the potential for small craft winds for many locations and gale force winds potentially in the gulf. Beyond this point operational guidance begins to falter as model spread grows, but ensembles are indicative of another system arriving immediately in the wake of the previous one, delivering another round of rain and wind to SE AK, with the active weather pattern likely to continue thereafter. This will bring temperatures more in lockstep with normal values as high temperatures return to the 50s, in departure of the 60s enjoyed during the previous week. The main changes to the forecast were significant increases in wind speeds and wave heights, along with some refinement to the QPF forecast, though exact timing for these remains difficult to precisely determine this far out. Likewise, increased PoP chances through the second half of the upcoming week given the growing agreement between operational models on at least two systems arriving after the Sunday system. Minor changes were made to temperatures and cloud cover. Minor adjustments made to temperatures to capture the diminished diurnal trends. && .AVIATION...VFR to MVFR conditions expected through the TAF period with BKN to OVC cigs increasing today ahead of an approaching system. Precipitation chances increase for PAYA by 18z this afternoon, slowly trending eastward towards the rest of the southeast TAF sites by 12z Sunday. Winds should remain 10kts or less with isolated sustained winds up to 15kts possible. && .AJK WATCHES/WARNINGS/ADVISORIES... PUBLIC...Frost Advisory until 9 AM AKDT this morning for AKZ319>321-325. MARINE...None. && $$ SHORT TERM...BC LONG TERM....GFS AVIATION...NM Visit us at http://www.weather.gov/Juneau