Talking the Tropics With Mike: Gordon well inland far from Jacksonville

Cat. 3 hurricane Florence over Central Atlantic

Talking the Tropics With Mike: Gordon well inland far from Jacksonville

Watch "Surviving the Storm".....

Local - Jacksonville/NE Fl./SE Ga - No direct impacts from the tropics through the upcoming weekend... 

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Gordon made landfall as a weakening tropical storm (just too much shear + nearby dry air) between 10:30 & 11:00pm EDT Tue. very near Pascagoula or about the Mississippi/Alabama border.  The main concern has been - & will be - flooding from heavy rain & - to some degree - storm surge... isolated tornadoes & waterspouts.  Squalls & rain bands far to the east & southeast of the center will continue to stream northward off the Gulf into the Fl. Panhandle & coastal Alabama resulting in additional flooding before diminishing Wed. night/early Thu. Heavy rain & flooding will accompany what's left of the surface low & upper level disturbance north all the way into parts of the Midwest.

Meanwhile.... it's back to business as usual for the Keys & S. Fl. after the Labor Day soaking.... & things will return to normal relatively quickly along the I-10 corridor from the Western Fl. Panhandle to Biloxi with no widespread significant damage.

(Radar imagery courtesy S. Fl. Water Management District)

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Elsewhere... "Florence" became the 3rd hurricane of the '18 Atlantic season Tue.... went "major" (Cat. 3) Wed. morning...  & continues over the Central. Atlantic.  While a full recurve is not a sure thing, don't get too caught up in individual run output of any particular model.  We've seen huge swings on virtually all the models with where Florence might be next week.  Even the "Euro-loved" model has shown differences of thousands of miles from one day to the next!  Bottom line at this point: East Coast needs to stay alert & up to date & one should always be prepared for mother nature's "wrath".

For the moment.... Florence is moving swiftly west/northwest & will turn more northwest over the Central Atlantic, slow then even stall - or edge slowly west - as strong high pressure moves across the N. Atlantic late week into the weekend & - an important point - becomes reinforced next week.  The turn west/northwest &/or stall will be something to place close attention to as the next upper level trough / surface cold front approaches & could then pick up the system again which would lead to a full recurvature, OR miss Florence which could allow for a more westward move.

The European model has generally shown a weaker tropical cyclone initially which is proving to not be the case. The GFS model has been showing a sharper & complete recurvature to the north with a stronger tropical cyclone earlier in the period as we're seeing now.  The two models have recently come into better agreement which, quite frankly, is meaningless this far out (week or so)... before the critical "fork in the road" over the weekend into early next week which is when the next upper level trough either swoops up the storm or leaves the tropical cyclone behind.  The UKMET model is in-between the GFS & European models. But all of the models are doing some flip-flopping & realize - as I've always said - they are just models.

I'm not ready to fully bite on any of the scenarios but the slowing of the storm over the Central Atlantic later this week/weekend/early 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. I will say that the tendency the latter part of this season has been for a pretty strong upper level ridge + surface high pressure from the upper U.S. east coast eastward into the N. Atlantic.  If this pattern remains in place or even strengthens then Florence will not likely have the escape route to the north.

Plenty of time to see how things evolve with Florence.  It would seem to me that any direct impact on the U.S. would not be until the middle to end of next week - from approximately Sept. 12-16th.  However, easterly swells emanating west from the hurricane will start arriving at Jacksonville & other east coast beaches over the upcoming weekend.

The map below is a mirror of the above spaghetti plots but shows an ensemble of all the model runs. DEFINITION OF ENSEMBLE MODELING: A set of forecasts that present the range of future weather possibilities. Multiple simulations are run, each with a slight variation of its initial conditions and with slightly perturbed weather models. These variations represent the inevitable uncertainty in the initial conditions and approximations in the models. They produce a range of possible weather conditions.

It's worth noting that there are model runs all the way to the U.S. and are model runs showing recurvature.  BUT there has been a definite trend west the last several days.

Otherwise.... the well advertised Atlantic changes - regarding potential storm development - are underway & should continue into at least the middle of Sept. 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).  The upper level map below from early Sunday shows a strong ridge of high pressure over the Eastern U.S.  This ridge guides Gordon on beeline from the Keys to the Central Gulf coast.  The upper level ridge will be critical the next few weeks as tropical cyclones & waves move westward across the Atlantic.  The orientation, position & strength of the ridge will help determine any possible hits on the Caribbean, U.S. &/or Mexico.  Combine this set-up with the approach of the peak of the season, less shear overall, warm ocean temps., lots of moisture & a MJO pulse, & you get an active period in the tropics/Atlantic Basin.

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Also of concern.... another wave - possibly two - that will move off the coast of Africa during the next week or so.  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.

The map below shows - in simplest terms - rising (green) & sinking (brown) air (related to the MJO).  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.

Florence followed by a couple strong tropical waves:

Spaghetti (model) plots for wave '92-L' over far E. Atlantic:

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 hurricane Norman moves west but likely to stay far enough northeast of Hawaii to only result in some sea & surf impacts on the north facing beaches... & Olivia west of Mexico moves westward.

Norman:

Olivia: