"Talking the Tropics With Mike": Remants of "Julia" along east coast - Sept. 21st

Sept. 21, 2016 — Tropical storm "Karl" over the Central Atlantic... "Lisa" far E. Atlantic....

JUST PAST THE PEAK OF THE HURRICANE SEASON...  You should always be prepared & aware.  First Alert Hurricane Center ** here **.  Reminder that flood insurance policies take 30 days to take effect..... & will not be written when/if a named storm is nearby.

The last NHC advisory on  "Julia"  was issued late Sunday.  Shear finally had its way with the system & that shear will only increase more with the approach of an upper level trough. But the remnants are interacting with a frontal boundary & upper level trough to produce a good deal of convection from coastal N. Carolina north to New Jersey.  No true & strong redevelopment is expected to occur but some lingering moisture + upper level disturbances rotating through the backside of the trough will bring a few showers & storms to the First Coast.

Tropical cyclone "Karl" continues to march westward & is trying fighting the good fight against shear & dry mid & upper level air.  A pretty vigorous upper level low is to the immediate west of "Karl" & until -- & unless -- the two systems become farther apart &/or the upper low weakens, it will be difficult for "Karl" to thrive.  The more shallow this system remains, the better chance it ends up farther west in the long run as models have been slowly trending west before a recurve.  In addition -- an important nugget to keep in the back of our mind -- forecast models as a whole this season have often been too far east or too early in other words - with recurvature.  So we have a couple of significant considerations while tracking & forecasting "Karl".  There are indications that conditions over the SW Atlantic late this week into the weekend could be quite favorable for strengthening.   Forecast models are generally pretty insistent on a full recurve for  "Karl", but the longer the cyclone stays weak, the more west the system is likely to get.   An upper level trough late in the week/weekend will also be pivotal as to whether or not "Karl" takes the sharp turn to the north which is the indication given that an upper level trough should hang over the east coast while a center of the Bermuda High is over the Central Atlantic.  This should create a decent alleyway for which "Karl" can follow.  "Karl" could be pretty close to Bermuda by the weekend as a hurricane reaching Jacksonville's latitude but hundreds of miles to the east late Fri. or so.  Given the distance from Jacksonville & expected intensification, easterly swells from "Karl" could reach First Coast beaches by late Thu./Fri.

Water vapor imagery below shows a good deal of dry air over the Central Atlantic which has been helping to limit the intensification of "Karl" so far.

The wind shear (red lines represent strongest shear) analysis shows shear gradually weakening in advance of "Karl" though the juxtoposition of an upper level trough up against "Karl" is resulting in a hostile overall environment for "Karl" so far.... lots of shear right now over the Southern Caribbean.

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Gulf of Mexico:

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East Atlantic:

Satellite imagery centered on Africa & the far E. Atlantic shows tropical waves continuing to move westward - pretty classic for this time of year.  A wave that moved off Africa over the weekend is now tropical storm "Lisa" - the 12th named storm of the season.  "Lisa" stays over the E. Atlantic & will be of no threat to the U.S.  Yet another wave will move off Africa in a few days with at least some potential for development.

"Lisa" is already nearing its peak as shear will be strongly increasing soon followed by a turn to the north then northeast over cooler water thanks to an approaching upper level trough of low pressure.

Lots of warm water to help "feed" tropical cyclones.  Water temps. of 28 degrees Celsius equates to 82 degrees Fahrenheit.  Tropical cyclones generally need at least 80 degree water to thrive.

Sea surface temps. vs. average:

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