Weather

Talking the Tropics With Mike: Tropical storm Florence develops over the far E. Atlantic

Sept. 1, 2018 — The "Buresh Bottom Line": Always be prepared!.....First Alert Hurricane Survival Guide... City of Jacksonville Preparedness Guide... Georgia Hurricane Guide.

Watch "Surviving the Storm".....

Local - Jacksonville/NE Fl./SE Ga - impacts from the tropics through the holiday weekend: NONE (but there still will be rain, heavy at times along with a moderate to high rip current risk at area beaches)......

The Atlantic Basin will be more active during Sept. which, of course, would be climatologically expected...

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 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 has strengthened into tropical storm "Florence" over the far E. Atlantic.  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 which would lead to a full recurvature, but the pause will be something to monitor & consider.  The European model shows a weaker tropical cyclone which would allow for farther west movement (with the trade winds) while the GFS model shows a sharper & complete recurvature to the north with a stronger tropical cyclone.  The UKMET model is in-between.  I'm not ready to fully bite on any of the scenarios but the slowing of the storm over the Central Atlantic by the middle next week will be a crossroads after which will be the critical move north as Florence is picked up by the next upper level trough or a miss by the trough which would lead to a storm with a higher potential to get farther west.  Plenty of time to see how things evolve with Florence.

Also of note - & interesting - is the European model which continues to try to develop a tropical system near Fl. by Sunday/Monday but has generally 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 partly due to an upper low just east of Jacksonville.  This is a situation to watch, but I have my doubts in the short term.  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 while moving away from Florida as shear becomes weaker.

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.  A moderate to high rip current risk at area beaches.

Also of concern.... another wave - possibly two - that will move off the coast of Africa next week.  Either or both of these waves will have the potential to move farther west over the Atlantic as high pressure tries to assert itself across parts of the Central/Northern Atlantic.  Just how strong the Bermuda high is - or is not - will go a long ways in determining whether or not waves/tropical cyclones can move all the way across the Atlantic.

Again - 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....

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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:

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

The Atlantic Basin....

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.  Triplets are spread out between Hawaii & Mexico: Miriam (left in the imagery below) is turning sharply north & will weaken while Norman moves west... & a new tropical depression west of Mexico moves westward.  All 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.... once super typhoon "Jebi" is forecast to hit Japan during the early to middle part of next week as a weakening system - tropical storm or Cat. 1 intensity - leading to heavy rain, strong winds & rough seas.