Talking the Tropics With Mike: Tropical depression six forms but no impact on Jacksonville

Aug. 31, 2018 — The "Buresh Bottom Line": Always be prepared!.....First Alert Hurricane Survival Guide... City of Jacksonville Preparedness Guide... Georgia Hurricane Guide.

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Local - Jacksonville/NE Fl./SE Ga - impacts from the tropics through the holiday weekend: NONE......

The Atlantic Basin will be more active over the next couple of weeks....

The Atlantic changes - regarding potential storm development - are underway & should continue into at least the middle of Sept. Tropical waves moving west off Africa are increasing in number & intensity & at least a couple waves are pretty likely to develop.  The uptick in activity coincides with a very persistent pattern of surface & upper level high pressure is anchored over or near the N. Atlantic which implies lower pressures to the south (the ol' what goes up, must come down postulate).

Tropical depression #6 is just off the coast of Africa & will gradually become "Florence".  There is the potential for heavy rain + some wind for the Southern Cabo Verde (Cape Verde) Islands where a tropical storm WARNING has been issued.  This system - as the storm becomes stronger/deeper - will turn more northwest over the Central Atlantic then stall as strong high pressure moves across the N. Atlantic next week.  This pause - & even a turn west/NW - will be something to watch but indications are that the next upper level trough / surface cold front will then pick up the system again causing full recurvature, but the pause will be something to monitor.

Of note - & interesting - is the European model which has been trying to develop a tropical system near Fl. by Sunday/Monday but now has recently backed off showing a weaker, later to develop system.  Social media & some die hard European model-bent forecasters - including some local "yocals" -  are jumping all over this development.  I remain not ready to go there yet.  Such development would fit the pattern overall, but the details don't lend a lot of support yet for this scenario.  The European seems to be latching on to the northern portion of a wave that's producing disorganized showers & t'storms over the NE Caribbean & far SW Atlantic. Shear is strong in the area of the wave now.  This is a situation to watch, but I have my doubts.  In any case, any low pressure that develops near Fl. Sun./Mon/Tue. would be slow to organize & relatively weak then have perhaps more potential over the Gulf next week but even then I don't see this low as becoming something real strong.

So I see no changes to the local - Jacksonville/NE Fl./SE Ga. holiday weekend forecast: hot/humid... onshore flow off the Atlantic... scattered overnight/morning/midday convection at the beaches/intracoastal... scattered inland afternoon showers & storms with bands of rain & storms increasing by Monday.

Also of concern.... another wave - possibly two - that will move off the coast of Africa next week.  Either or both of these waves would likely move farther west over the Atlantic compared to what will become "Florence" but still a long ways to go on this development.

The overall pattern - less shear... a little more moisture... an MJO pulse ..... + approaching the peak of the hurricane season all adds up to staying vigilant in the coming weeks.

The map below shows - in simplest terms - rising (green) & sinking (brown) air.  The green areas - in the tropics - are more favorable for tropical development & this kind of pattern is likely to overspread the Atlantic Basin in the coming weeks.

Note the disorganized showers & storms around Puerto Rico, Hispaniola & the SE Bahamas....

Forecast model plots for the likely soon to be tropical cyclone (90-L) off the coast of Africa... the wave that moves into the Gulf of Mexico next week... & hurricane "Norman" over the E. Pacific:

Mid & upper level wind shear (enemy of tropical cyclones) analysis (CIMMS). The red lines indicate strong shear......

0

The Atlantic Basin....

1

Caribbean:

Gulf of Mexico:

Water vapor imagery (dark blue indicates dry air):

Deep oceanic heat content continues to increase over the Caribbean & Gulf of Mexico as one would expect now that we're in August.....

Sea surface temp. anomalies show a general recent warming over a good portion of the Atlantic Basin ....

SE U.S. surface map:

Surface analysis centered on the tropical Atlantic:

Surface analysis of the Gulf:

Caribbean:

The E. Pacific remains a busy basin.  Twin storms Miriam (left in the imagery below) will turn sharply north while Norman moves west.  Both will stay over open water through the weekend though Norman may be a storm for Hawaii to keep an eye on in 7-10 days or so.

In the W. Pacific.... super typhoon "Jebi" is forecast to hit Japan during the early to middle part of next week as a weakening system but still possible at Cat. 1 intensity leading to heavy rain, strong winds & rough seas.

Cox Media Group