Area Forecast Discussion
Issued by NWS Juneau, AK
Issued by NWS Juneau, AK
516 FXAK67 PAJK 142329 AFDAJK Southeast Alaska Forecast Discussion National Weather Service Juneau AK 329 PM AKDT Sun Jul 14 2024 .SHORT TERM...The heavy rainfall seen over the northern panhandle and outer coast will continue Sunday night and into Monday morning as the plume of moisture remains anchored between a ridge in the southern panhandle and the stalled frontal boundary along off the coast of the panhandle. This boundary will finally push inland overnight Sunday into Monday. For more in depth information on current flood products out for the northern panhandle and expected impacts from precipitation, see the hydrology section. As the front pushes inland, the surface ridge over the southern inner channels will continue to be pinched up against the coast mountains and winds along the outer coast and inner channels will increase once more. Southern inner channels will see a bump in winds from the south as the front finally pushes through the panhandle Monday. Winds will be gusty across the panhandle as the front pushes inland Monday before finally beginning to slacken Monday night. With the continued southerly flow through the short term timeframe being offset by precipitation, temperatures will continue to remain seasonably cool. .LONG TERM.../Tuesday through Sunday/... After the previous heavy rain event for the start of the week SE AK weather while active will not be as impactful. The 500 mb low over the AK interior remains the driving force for this weeks rain fall. through the week the center drops southward over the AK Gulf with lobes extending and continuing to rotate around it. By the next weekend models have some alignment on the 500 mb pattern, just not where any of the features will actually be. Tuesday at the surface ridging over the Eastern Gulf and an open wave trough over the NE Gulf will keep onshore flow and showers over much of the region. Tuesday into Wednesday a series of surface waves track up the lee side of the ridge from the N Pacific bringing shots of increased precip with highest amounts over the south. Late in the week tracking the next low moving in. As of now the GFS/Canadian track should follow the previous surface waves but having a more solidified structure but the timing difference between these models is almost 24 hours. Latest ECMWF doesn`t even show a closed low moving in. GESF ensembles have a closed low but not a deep with low probability of 6 hour precip exceeding 0.25 inches. ECMWF ensembles are similar to operational, not much of a feature depicted. && .AVIATION...Weather conditions for southeast AK are a mixed bag this afternoon with ongoing MVFR/IFR while pockets of VFR and LIFR conditions are being reported. These conditions are expected to continue through the evening and overnight periods as ongoing rain provides lowered CIGs and VIS. Along with the lowered weather conditions, AAWU guidance through the evening continues to show turbulence and icing for the northern panhandle with icing extending farther south to near the southern panhandle. LLWS reports have also been coming in throughout the day. This is expected to diminish during the overnight hours but should pick back up again during the daytime hours, especially along the outer coast of Baranof Island. && .MARINE...For coastal waters, the front has slowed considerably, with the gradient weakening slightly along the northern coast. While no longer seeing gale force winds, seas will remain elevated before subsiding overnight Sunday into Monday morning. For the southern outer coast, winds will pick up due to the approaching front displacing the ridge over the area. Coastal waters will see winds reaching 25 kt with gusts up to 35 kt, with similar conditions expected for Clarence Strait as the front progresses. By Monday night the front will have pushed through the panhandle and winds and seas will begin to subside from north to south. && .HYDROLOGY...Rain continues for the northern panhandle with the heaviest rain expected this evening and into tomorrow morning for the northern panhandle. Most places have recorded between 1 and 6 inches of rain across the panhandle. With that much rain, water levels across rivers and streams have come up. Smaller streams across the Mendenhall valley have come up and are near bankfull. Larger rivers such as the Mendenhall River will see a delayed response due to the amount of rain falling at higher elevations. This rain along with the warm temperatures will allow for increased runoff to reach the river basin but at a more delayed rate. Some river and stream increases across the Haines and Skagway areas have been less from the rain impacting the area and instead are from increased snow and ice melt due to warm temperatures aloft. Rain across the area is expected to decrease as we head into the day tomorrow as the atmospheric river shifts farther south. One last resurgence of rain is expected tomorrow though as a shortwave works into the area but the rain is expected to continue to spread farther south. && .AJK WATCHES/WARNINGS/ADVISORIES... PUBLIC...Flood Watch through Monday evening for AKZ318>321-325. Strong Wind until 7 PM AKDT this evening for AKZ318. MARINE...Small Craft Advisory for PKZ012-013-032-033-036-641>644-651-652- 661>664-671. && $$ SHORT TERM...STJ LONG TERM....PRB AVIATION...SF Visit us at http://www.weather.gov/Juneau