Talking the Tropics With Mike: Intense hurricane Lorenzo while Karen struggles

Sept. 26, 2019 — The "Buresh Bottom Line": Always be prepared!.....First Alert Hurricane Survival Guide... City of Jacksonville Preparedness Guide... Georgia Hurricane Guide.

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RECAP "Hurricane Dorian: A True Tropical Beast"

*** Though the Atlantic remains active, there are no hreats to Jacksonville/NE Fl. & SE Ga. or any of the coastal U.S. anytime soon. Dangerous rip currents will continue at area beaches along with rough seas & surf due to a combination of distant tropical cyclones & persistent generally onshore flow.

ATLANTIC BASIN:

(1) tropical storm Karen over the SW Atlantic

(2) Hurricane Lorenzo far E. Atlantic.

Lorenzo is certainly no problem for the U.S. Karen will slow & likely struggle to survive while turning gradually to the west/southwest.

Jerry became post-tropical Wed. leaving us with two named storms over the Atlantic.

TROPICAL STORM KAREN:

Tropical storm Karen was upgraded early Sunday over the Eastern Caribbean & has been battling shear since its inception & the next few days will be no different. Nearby dry mid & upper level air may also become an issue. An upper level low to the storm's west - near & east of the Bahamas - is adding to the shear but even more importantly helping to keep Karen - for now - moving northeast deeper into the Atlantic & farther to the east of the U.S. The upper low will weaken & peel back to the west & southwest eventually losing its influence on Karen.

Lots to consider regarding Karen & its future. Conditions continue to look marginal - at best - & Karen could devolve into a depression or open wave at just about anytime. However, Karen has had a tendency to sort of reinvent itself just when one thinks it may be on its last leg.

If Karen can survive shear becomes less for a time over the weekend into early next week over some very warm ocean water. The center will probably jump around some as the system continues to try to organize & develop in the short term (this has already been evident since Tue). Steering currents collapse by the weekend as high pressure builds to the north of Karen effectively trapping the storm over the SW Atlantic. Once the high is strong enough (& as Karen remains weak), Karen will begin a westward movement (possibly after a small loop) that may even become more southwest. By the middle of next week, shear begins to increase again over & east of the Bahamas & Karen will re-enter a very hostile wind environment. If Karen is still "a thing" at this point, it would seem this next area of high shear could finally be Karen's demise.

The European model has continued west & slower but is now not as strong. The GFS model maintained its west & rather weak track. The UKMET model has Karen turning west as well as generally a weak tropical cyclone. The UKMET has not had a great season so far this year. Models are hinting at another stall once in/near the Bahamas &/or Florida next week but Karen may little more than a tropical wave at that point.

Spaghetti plots for Karen:

Ensemble plots for Karen:

HURRICANE LORENZO:

A large/impressive tropical wave came off the coast of Africa Sunday & was deemed t.d. #13.... then upgraded to tropical storm "Lorenzo" Mon. morning & to a hurricane early Wed. - over the E. Atlantic. All indications are that sprawling Lorenzo will be an early turn to the north staying over the Eastern & Central Atlantic as the tropical cyclone maintains "major" intensity as a Cat. 3/4 over open water.

An examination of dust over the Atlantic shows generally less dust over the basin vs. past months which is fairly typical for September & the peak of the hurricane season. Much too much is made of the dust & tropical cyclones. It's not all uncommon for tropical waves to simply "wait out" the dry air & dust organizing once the wave is clear of the dry atmosphere.

2019 names..... "Melissa" is next on the Atlantic list (names are picked at random... repeat every 6 years... historic storms are retired (Florence & Michael last year) & Dorian is almost certain to be next:

East Atlantic:

Mid & upper level wind shear (enemy of tropical cyclones) analysis (CIMMS). The red lines indicate strong shear of which there is plenty across the Atlantic at the moment:

The Atlantic Basin:

Water vapor imagery (dark blue indicates dry air):

Deep oceanic heat content:

Sea surface temp. anomalies show a warm Gulf of Mexico, Central & Northwest Atlantic while the "Main Development Region" (MDR) remain cooler than avg. Note the leftover upwelling (cooler water) left behind Dorian near the Bahamas (though starting to "mix out"):

While the MDR is cooler than avg., it's important to realize the water is still warm enough to support tropical systems....

SE U.S. surface map:

Surface analysis centered on the tropical Atlantic:

Surface analysis of the Gulf:

Caribbean:

You will see me fairly often refer to the "Velocity Potential Anomalies" - usually in stride with the Madden-Julian Oscillation (MJO). In simplest terms, the green lines correlate with rising air which can help lead to conditions favorable for tropical cyclone development. And such is the case as a very strong "pulse" of rising air spread from the Pacific into the Atlantic Basin. & right on cue - a number of named storms have popped over both basins the past couple weeks. This pattern of the MJO implies an active period over the Atlantic that may very well continue into early Oct. Realize active does not necessarily mean "bad" - as in landfalling. Track will come down to the orientation of the jet stream, Bermuda high & other large & even small scale weather features that will ultimately steer the tropical cyclones. Bottom line: stay up to date on what's going in the tropics!