Area Forecast Discussion
Issued by NWS Juneau, AK
Issued by NWS Juneau, AK
519 FXAK67 PAJK 232352 AFDAJK Southeast Alaska Forecast Discussion National Weather Service Juneau AK 252 PM AKST Sat Nov 23 2024 .SHORT TERM...Winds across the panhandle today have started to trend downward but some areas are still seeing strong winds. With the winds trending down, we have been able to let the high wind warning expire for Juneau. With the decreased winds and clear skies for the area, temperatures will remain cold during the overnight hours. With the continued cold and clear pattern, only minor changes were made to the wind and left the rest of the going forecast. The only changes made for the short term was to increase the possibility of precipitation for the NE Gulf coast as chances are starting to increase late in the period. .LONG TERM.../Monday into Thanksgiving/... Any chance of precipitation returning to the panhandle rests on the blocking ridge over the western gulf breaking down. Ensemble models are trending towards a stronger shortwave moving down from the Bering Sea, successfully bringing some precipitation chances to the northern half of the panhandle. Current forecast continues to reflect pessimistic snowfall totals for Monday through Tuesday. While the forecast leans toward higher snow totals, the story of snow is actually much more uncertain. While the overall setup for heavy snow is present, ultimately, what hinges on this forecast is the available moisture for snow development. 850 mb winds from the S to SW flowing over a reinforcing stable layer from northerly winds down Lynn Canal will remain persistent for more than 24 hours. Currently, just north of Icy Strait, impressive frontogenesis at 850-700 mb looks to stick around, driving heavier snowfall. Furthermore, maximum omega, around -30 ubar/s at -10 degrees C. At this point, most moisture is in the lower levels of the atmosphere with relative humidities above 700 mb being increasingly uncertain. If the profile is more moist than expected, then northerly winds along with moderate to heavy precipitation rates will keep the entire event for the Icy Strait Corridor as snow. Following the initial shortwave, a secondary shortwave moving along the initial ridge Wednesday and Thanksgiving may reignite snowfall for the Juneau area, may push the main snowfall band southward, or may be weak enough that northerly dry air will limit any precipitation from developing. Ultimately, observing upstream how each shortwave behaves will be paramount to determining how each system next week will behave. Stay tuned for updates. && .AVIATION...VFR conditions with clear skies and full visibility will continue here in SE AK through tonight. Still dealing with the strong outflow winds this afternoon but the LLWS looks to lighten up this evening. Smoother flying weather in store late Saturday night into Sunday. && .MARINE...Outflow winds are expected to continue through the evening but have already started to trend downward across portions of the panhandle. Elevated winds and seas are still possible through the Inner Channels as well as along the outer coast near entrances to the Inner Channels. Winds will continue their downward trend as the east west channels become more favored. These channels will still see some strong winds but should still a trend downward headed into next week before our next system moves into the panhandle. && .AJK WATCHES/WARNINGS/ADVISORIES... PUBLIC...Strong Wind until 3 PM AKST this afternoon for AKZ318. Strong Wind from Sunday morning through Sunday afternoon for AKZ318. Winter Storm Watch from late Monday night through Tuesday evening for AKZ320>322-325. High Wind Warning until 3 PM AKST this afternoon for AKZ325. Strong Wind until 9 PM AKST this evening for AKZ325. MARINE...Gale Warning for PKZ012-013-662. Small Craft Advisory for PKZ031>034-641>643-661-663. && $$ SHORT TERM...SF LONG TERM....NC AVIATION...GJS MARINE...SF Visit us at http://www.weather.gov/Juneau