"Isaac" Remnants into Ohio & Tennessee Valley; "Leslie" Battles Shear But Still Producing Intense Thunderstorms...........
The remnant low/upper level disturbance that was "Isaac" is moving east into the Ohio Valley & turning southeast toward the Tennessee Valley. Forecast models show the mid & upper level disturbance maintaining itself & dropping south/southeast then south across the Eastern & Southeast U.S. this week reaching the Gulf Coast mid to late week(!). "Ivan" made a somewhat similar loop in 2004 (see 4th & 5th images below). It doesn't appear a surface low will accompany the disturbance, but the upper level energy could enhance showers & t'storms during the middle of next week. There may also be possible interaction with an upper level cold core low near Fl. While little surface low development is currently indicated by the forecast models, we'll have to watch for possible surface development near or just east of Fl. about Wed.-Fri. Click
here for updated storm summaries on 'Isaac" from the Hydrometeorological Prediction Center.
IVAN'S TRACK IN 2004:
"Leslie" has been putting up a good fight against moderate shear
& -- so far -- has had no problem surviving. Strong shear & some dry air will hammer away at the cyclone the next few days as "Leslie" is sandwiched between a compact but strong upper low in the Bahamas & an upper level trough to Leslie's northeast over the Central Atlantic. Shear will relax starting midweek which could allow for significant strengthening. The upper level trough tugging "Leslie" north/northwest will not entirely pick up the cyclone leaving "Leslie" in a weak steering flow midweek which will cause the storm to stall at or just north of Jacksonville's latitude in the Central Atlantic. There could be some jog west at that point but early indications are that "Leslie" will still get steered north then northeast in time. Still a long way out with plenty that can change. And if we look at the W. Pacific last week, the 2nd typhoon moved to the China coast west & southwest of Japan, so we'll have to beware of a farther west track in the long run than forecast models are currently indicating. All will hinge on the timing & intensity of what look to be a strong upper level trough that will dig into the Eastern U.S. late this week into the weekend. "Leslie" should start to increase its forward speed to the north or north/northwest as the trough approaches. This move north could be helped the upper low near Florida as the upper low moves east/northeast though -- in the long run -- what looks like an expansive "Leslie" circulation could end up absorbing the upper low.
In any case... "Leslie" should be strong enough & large enough to send an easterly swell to First Coast beaches this week increasing the rip current risk.
The last advisory was issued on "Kirk" in the Northeast Atlantic late Sunday.
The rest of the Atlantic Basin has gone quiet. The parade of tropical waves coming off Africa has eased (see last satellite image below), & it looks like we're in for a period of less activity -- from a tropical standpoint & excluding "Leslie", of course) -- in the Atlantic Basin that could 1-2 weeks. The one area to watch will be possible close-in development (to the U.S.) with the upper level trough that will be persistent over or near the east coast of the U.S. (as alluded to earlier in this discussion at the top) possibly in combination with the upper level disturbance that was "Isaac". Waves coming off Africa will pick up again by the weekend with some development possible the following couple of weeks as we reach the peak of the Atlantic Basin hurricane season.
