... Dry high pressure builds in through Thursday, resulting in a slow cooling trend. Meanwhile, Hurricane Ian will move north into the eastern Gulf of Mexico and approach our area late in the week, affecting our weather this weekend.
NEAR TERM /THROUGH TONIGHT/... As of 1150 AM: No major changes needed as the forecast remains on track. Otherwise, cool and dry high pressure builds in from the north today. Winds turn more northwesterly this afternoon, with low- end gusts possible across the mountains. There may be a few clouds but skies should be mostly clear. Highs will be up to 10 degrees below normal across the mountains and up to 5 degrees below normal elsewhere.
Gusts diminish this evening with winds turning back more northerly. Cirrus will begin increasing from the south overnight. Lows will be around 10 degrees below normal.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... As of 230 AM Tuesday...A deep upper trough axis will start out along the spine of the Appalachians Wednesday, then will exit and lift NE of the area Thursday. Sfc high pressure will slide across the Great Lakes, reaching Upstate NY by Thursday evening. Meanwhile, Ian will be drifting NWD across the eastern Gulf. The latest guidance has slowed Ian's progress down a tad, so moisture and PoPs associated with the northern bands of Ian may not enter the forecast area until close to daybreak Friday. A persistent NELY low-level flow will keep max temps about 5-10 deg below normal both Wednesday and Thursday, while min temps will be closer to normal. Cirrus may start streaming cross at least the eastern parts of the forecast area as early as Wednesday aftn, but thicker overcast doesn't arrive until Thursday night. Winds will be marginally breezy Wednesday, but breezier Thursday, as pressure gradient tightens between the high to our north and Ian to our south.
LONG TERM /FRIDAY THROUGH TUESDAY/... As of 330 AM Tuesday...The latest model trends have been slightly east and a little slower with Ian. The latest NHC track has making landfall close/just north of the Tampa area Thursday morning, tracking rather slow across northern FL, and not getting into southern GA until early Friday evening. By this point, there is still a lot of uncertainty on how the center of Ian will track, as it will have weak steering flow and will be undergoing extratropical transition. With that said, unless the system gets completely blocked, we should see some heavy rainfall across the forecast area. On the current forecast track, the period of heaviest rain potential looks to be Friday night thru Saturday. From there, the low-level flow will weaken and veer from easterly to southern. There may also be a dry slot punch in Saturday night, helping limit rain rates. Storm total rainfall Friday thru Sunday may be 3-6" with locally higher amounts along the eastern escarpment. The experimental Days 4 and 5 Excessive Rainfall Outlooks have a slight risk creeping into the southern half of the forecast area Fri-Fri night, and the entire area Sat-Sat night, and that looks good. It will also be windy, mainly due to gradient winds between Ian's circulation and a stubborn sfc high over the Northeast. The actual storm will likely weaken to a tropical depression or post-tropical low, but wind gusts may approach tropical-storm-force along the high terrain Fri night-Sat, with a 40-50 kt easterly 850 mb jet punching into the area. With gusty winds, coupled with saturating soils, we will continue to message the possibility of at least isolated power outages as a result of falling trees. TC tornado threat looks likely to remain low, given the slight eastward shift in track.
The remnants of Ian is forecast to slowly drift north and east of the area, but may take it's time, as the medium range guidance doesn't have a kicker trough enter the Great Lakes and Ohio Valley until late Monday or early Tuesday. So we may keep unsettled weather across the forecast area Sunday and into Monday. Additional rainfall should be fairly light, as the low occludes, shunting the tropical 2+ inch PWAT air well to our east. Temps will feature a lower than normal diurnal range, with lows above normal, and highs below normal thru the period.