Weather

Talking the Tropics With Mike: Atlantic trio of Jerry, Humberto & Imelda & E. Pacific crowded too

Sept. 19, 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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*** Though the Atlantic is very active, there are no threats to Jacksonville/NE Fl. & SE Ga. or most of the coastal U.S.  Dangerous rip currents will continue at area beaches along with rough seas & surf due to a combination of distant tropical cyclones & persistent onshore flow.

BUSY ATLANTIC BASIN:

(1) hurricane Humberto, Central Atlantic

(2) Jerry over the Central Atlantic - tropical storm WATCH for Northern Lesser Antilles

(3) "Imelda" low pressure area inland over Texas - severe flooding SE Texas

(4) parade of tropical waves from the Caribbean to Africa....... see why the next few weeks should be active at the bottom of this post.

HURRICANE HUMBERTO:

The combination of Humberto far to the east/northeast & high pressure to the north will result in a continuation of dangerous conditions at our (Fl./Ga. & much of east coast & Bahamas) beaches.  Rough seas & surf will only slowly & slightly subside & a very high rip current risk will continue through the weekend.

Tropical depression #9 was upgraded late Friday afternoon... to tropical storm Humberto late Fri. evening... & to a hurricane Sunday evening - while east of Florida & north of the Bahamas.  The hurricane sideswiped Bermuda with the eye moving north & west of the island but close enough for a brief period of sustained hurricane force winds. Weather conditions are rapidly improving on the island as Humberto moves away.

The positioning & strength of the Bermuda high over the Atlantic plus an incoming upper level trough over the Northeast U.S. is again (like Dorian & Humberto) playing an important role in the track of Jerry.

Sunday afternoon - at about 30-35,000 feet - there was a weakening trough will be over New England while the Bermuda high shifted some to the east.  This essentially left an alleyway over Fl. giving Humberto an "out" well to the east of Fl.  After a brief "rest" or stutter/wobble to the north or even northwest while northwest of Bermuda, Humberto will resume its northeast movement while accelerating to the N. Atlantic.

Ensemble model forecasts for Humberto show a nice shift east:

JERRY:

T.D. #10 formed from an African tropical wave & was upgraded to a depression Tue. morning & the 10th tropical storm of the season early Wed. with a move steadily - though slowly - west/northwest.  Though thriving for the moment, Jerry will be moving through a zone of high shear, so the tropical cyclone may become mostly steady state - high end tropical storm or low end hurricane - into the weekend.  While uncomfortably close by Fri. into the weekend to Puerto Rico, it looks like Jerry will be north of the Greater Antilles.  However, all the folks in the Caribbean nations/islands need to stay up to date on the latest forecasts.  Beyond this weekend, Jerry turns sharply northward following the "wake" of Humberto & the persistent weakness over the Western Atlantic staying east of the Bahamas & far to the east of the U.S. coast.

Bermuda may again be impacted by a hurricane by the middle of next week as Jerry moves into an area favorable for intensification upon turning north then northeastward.

IMELDA:

Time ran out for more significant development as Imelda made landfall at Freeport, Texas about 2pm EDT Tue. within hours of being upgraded near the Texas coast with sustained tropical storm force winds verified by several coastal reporting stations.  Very heavy rain & flooding will plague coastal SE Texas as far inland as Houston & as far east as Louisiana.  Catastrophic flooding has been occurring in & around Beaumont.

More than 2 feet of rain! for parts of SE Texas since Tuesday:

CENTRAL & EASTERN ATLANTIC:

There are a several active tropical waves over the Central & East Atlantic that will likely develop with long term track the big question mark (of course!).  Plenty of time to watch/monitor/track & "cipher".  Most of the more reliable global forecast models - European/GFS/UKMET - are bouncing around on development not to mention the location.  Also of interest.... a lead wave that had been weakening has now flared with some disorganized t'storms upon moving into the Eastern & Northern Caribbean - something to keep an eye perhaps over the Western Caribbean &/or Gulf of Mexico by the weekend into next week. And there are multiple strong tropical waves moving off the coast of Africa with at least one likely to develop by the weekend or shortly therafter.

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..... "Karen" 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 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 - 3 named storms over the E. Pacific & now 2 named storms over the Atlantic.  This pattern of the MJO implies an active period over the Atlantic that may very well continue into the first 10 days of 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!

Humberto & Jerry over the Atlantic (+ Imelda remnants).... Kiko, Mario & Lorena over the E. Pacific:

Lorena will be very close to the SW coast of Mexico through Fri.  If Lorena survives the land interaction, the storm will then move to near the Baja Peninsula by the weekend.