Watch "Surviving the Storm".....
Local - Jacksonville/NE Fl./SE Ga - No direct impacts from Gordon...
Tropical storm WARNINGS are in effect for the Keys, S. Fl. .... a hurricane WARNING is effect for the east tip of Louisiana & coastal Mississippi & Alabama... tropical storm WARNING for SE Louisiana & the far Western Fl. Panhandle... & storm surge WARNING for coastal Mississippi & Alabama... & storm surge WATCH for SE Louisiana & the Western Fl. Panhandle. Main concern will flooding from heavy rain & - to some degree - storm surge... isolated tornadoes & waterspouts. Meanwhile.... it's back to business as usual for the Keys & S. Fl. after a Labor Day soaking.
The circulation of "Gordon" improved dramatically early Monday only to seem to give in to a significant shear "zone" over the Northern/Central Gulf by late Mon./early Tue. But satellite & radar imagery show perhaps a bit of a comeback by midday Tue though the western & southwest portion of the circulation is still eroded to due to shear. There has also been at least a modest drop in the estimated central presure. (Radar imagery courtesy S. Fl. Water Management District)
"Gordon" - is moving swiftly west/northwest & will make landfall between approximately midnight & 4am CDT very near Biloxi, Mississippi a little east of New Orleans - as a high end tropical storm or low end Cat. 1 hurricane. The European model definitely wins the forecast model on this one & has stabilized on a move to the coast near New Orleans but as a weak storm. The GFS model shows a very weak system but with similar timing & location to the European model. While the water is very warm, Gordon is rather fast moving as tropical cyclones go + shear is formidable over the Gulf of Mexico & won't change much thanks to a stagnant upper level pattern of high pressure near the U.S. east coast north of Jacksonville. This makes exact intensity problematic but does make the track pretty straight forward - Central Gulf Coast. There is some chance that the upper high expands to the west which would make for more of a westward move upon approach to the Gulf Coast (as indicated by UKMET model) but not likely. Whether or not Gordon becomes a hurricane before reaching the Gulf Coast but it would really be more about semantics vs. true impacts. Either way - water will be the big issue. Gordon will quickly weaken once inland Wed./Thu. while moving northward into the Midwest but still enough upper level "energy" + a weak surface reflection to continue to produce heavy rain in the system's vicinity well inland.
Shear early Tue.... red lines indicate strongest shear... yellow moderate shear... green weak shear:
Elsewhere... "Florence" has become the 3rd hurricane of the '18 Atlantic season & continues over the E. 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.
For the moment.... Florence is moving swiftly west/northwest & will turn more northwest over the Central Atlantic, slow then stall - or even edge slowly west - as strong high pressure moves across the N. Atlantic late week. The turn west/northwest &/or stall will be something to watch but indications are that the next upper level trough / surface cold front could 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 generally shows a weaker tropical cyclone initially 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. But - again - all of them are doing some flip-flopping. 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. Plenty of time to see how things evolve with Florence. It would seem to me that any direct impact on the U.S. is at least 7-11 days away IF anywhere on the U.S. coast.
The map below is a mirror of the above spaghetti plots but shows an ensemble of all the model runs. It's worth noting that there are model runs all the way to the U.S. but the majority - SO FAR - indicate recurvature.
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 will guide the tropical wave near the Southern Bahamas into the Gulf of Mexico & away from Fl. by midweek. This 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.
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 strong tropical wave:
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....
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:
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.
In the W. Pacific.... once super typhoon "Jebi" has hit Japan & will continue to weaken but flooding & landslides will continue to be a problem for Japan through midweek.
Cox Media Group