Area Forecast Discussion
Issued by NWS Juneau, AK
Issued by NWS Juneau, AK
271 FXAK67 PAJK 152325 AFDAJK Southeast Alaska Forecast Discussion National Weather Service Juneau AK 325 PM AKDT Mon Jul 15 2024 .SHORT TERM...For the northern inner channels, a last impulse of heavy precipitation is expected through Monday evening associated with a short wave feature riding along the boundary. As such, a flood watch remains in effect for the northern inner channels through 10 PM Monday night. This feature is expected to lead to a brief increase in winds for the northern inner channels as the front pushes in tonight with some gusty winds for land areas as well. Winds will also pick up in the southern inner channels due to a pinching of the gradient with a weak ridge that had been helping to hold the front at bay down there. Northern parts of Clarence Strait have been reporting around 15 - 20 kt winds through the early afternoon, and with this front approaching expect winds overall to pick up to 25 kt or more before settling back down later on this evening. An inverted trough that is set to bring more moisture to the southern and central panhandle in mid range period will begin to build in from the south, which will keep winds out of the south overall for the southern panhandle leading up to mid week. For temperatures, the moderate to heavy rain and associated cloud cover have offset any significant gains the panhandle would have gotten from the persistent warm southerly flow in the low to mid levels, with minimal diurnal surface temperature changes of less than 10 degrees. While the far northern inner channels and NE gulf coast may see a brief break from this Tuesday, the majority of the panhandle will continue to see temperatures hover between 55 and 65 degrees, with the southern panhandle approaching 65. Overall remaining seasonably cool and wet for the short term period. .LONG TERM.../Wednesday through Monday/... To put it simply: with the way the ensembles and operational models have been shifting surface features from run to run have low confidence in the mid range and long range forecast. That`s not to say latest runs aren`t showing good agreement for both ensembles and some operational models. The main change is the flow pattern now keeping any of those larger features late in the week further to the south and thus putting SE AK under just onshore flow with lighter precip, lower wind speeds, and looking at more breaks in the rain. However...this was a change in just 24 hours...so...keep that in mind as we progress. Anyway, the 500 mb low previously over the AK interior drops southward over the AK Gulf with lobes extending and continuing to rotate around it, just further south. To the west a blocking pattern develops with a ridge over the western gulf and another low past the Bering. At the surface on Wednesday the remainder of the elongated low from Tuesday goes northward along the Eastern Gulf. Good moisture feed from the south producing another round of moderate to heavy rain fall. BUT, total rainfall not in the realm of what occurred Sunday and Monday. 24 hours amounts likely only in the 1 to 2 inch range. Thursday into Friday high pressure expands over the Gulf moving the Wednesday system eastward and possibly dropping rain chances for portions of the panhandle. Plus the high pressure should keep the main part of Friday low that was going to hit SE AK to the south and outside of our area, but still allow some rain bands to cross over us. && .AVIATION...Rather low aviation weather today with MVFR and some IFR conditions (ceilings down to 500 ft and vis down to 2 miles in some cases) widespread across the panhandle due to an atmospheric river dumping rain. Not a whole lot of wind with this feature though. Low level wind shear and turbulence reports have been few and far between today so far. Flying weather is looking to stay with MVFR or lower ceilings and Vis through tonight at least with the possibility of improving conditions on Tuesday. Lower conditions possible for Tue night and Wed as yet another system moves in from the S. && .HYDROLOGY...Wet conditions continue, but there is a reprieve in sight. Heavier rain is expected to end Monday evening as the atmospheric river finally moves off to the east. Area rivers in the north should crest Monday or Monday night before receding. Currently only Jordan Creek near Juneau, and Chilkat River near Haines are above minor flood stage, but Auke Lake near Auke Bay could join them briefly later this evening. Other rivers and streams in the north are running high and/or are near bankfull, but no others that are gaged are expected to start flooding. We get a brief break on Tuesday before another round of rain comes in for Tue night and Wed. This one does not look as long of duration as the last one and it is aimed more at the central and southern areas rather then the north this time around. Decided to issue a Hydrologic outlook for it. && .AJK WATCHES/WARNINGS/ADVISORIES... PUBLIC...Flood Watch until 10 PM AKDT this evening for AKZ318>321-325. MARINE...Small Craft Advisory for PKZ036-641. && $$ SHORT TERM...STJ LONG TERM....PRB AVIATION...EAL Visit us at http://www.weather.gov/Juneau