TROPICAL CYCLONE FORMATION: BONNIE / INVEST 93L (60%)
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(T. F. “Storm” Walsh III)
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CURRENT 2016 TROPICAL CYCLONE TALLY:
TOTAL STORMS: 2
INTENSE HURRICANES: 0
Good day everyone!
Looking at various agency sites a couple days ago, it was unclear as to whether or not the circulation that exited into the Atlantic again was ex-BONNIE or INVEST 92L which was designated on a few sites. Since the NHC is issuing advisories again on Tropical Depression BONNIE, the logical choice is that although BONNIE’S convection totally dissipated, a LLC appears to have remained enough intact while over land, and upon exiting into the water once again has retained the name BONNIE, vice the naming of another system.
BONNIE has once again become a Tropical Storm. I had mentioned this in my previous past couple of forecasts that she might very well attain storm status again.
In any event, the latest advisory from the NHC provided the following information:
5:00 PM EDT Fri Jun 3
Location: 35.9°N 70.5°W
Moving: E at 13 mph
Min pressure: 1006 mb
Max sustained: 40 mph
BONNIE has had a nice flareup of convection during the past few hours, very close to, or over the LLC, which has maintained long enough for the upgrade, along with the increase in wind velocity
Being that BONNIE is moving to the east, and is forecast to continue in that general direction before and weakening into an open trof by 72 hours, this will be my final post on BONNIE.
Elsewhere, the possible tropical formation I’ve been discussing over the past 2-3 days, of which the global models have been consistent in development over the W. Caribbean Sea appears to be coming to fruition. Tropical Disturbance INVEST 93L has been designated over the west central Caribbean. As of the 18Z ATCF BTK (Automated Tropical Cyclone Forecasting System Best TracK) product, the following information was available on INVEST 93L:
Location: 16.6°N 83.5°W
Moving: WNW at 10-12 mph
Min pressure: 1012 mb / 29.88 in.
Max sustained: 30 mph
The NHC has designated a 60% (MEDIUM) chance a cyclone formation during the next 5 days.
The disturbance is moving to the WNW, and I expect this motion, with possibly more of a northern component, to continue during the next 36-48 hours, before possibly slowing and beginning a more northerly turn, based on the current forecast steering layers maps, valid 00Z this evening. Looking at the recent current steering layer maps, steering appears to have more of a NW flow, vice a true WNW flow. This, combined with the steering currents forecast, leads me to believe that development may begin to occur a little bit east of the Yucatan Peninsula, or more over the eastern tip, as opposed to right on the Peninsula. Analysis of the recent global models runs indicates this system may push further west into the GOMEX to near 85 west, before recurving. For all I know, the models may be correct, albeit they really have no LLC, warm core at the moment to initialize. Anyway, my thinking is just another possible scenario in the scheme of things.
The majority of the models do bring this ashore around the Big Bend, to just near the Panhandle of Florida in about 3-4 days. The outlier is the NAVEGM, which brings it closer to the west central Florida area. I will not totally rule this out, just yet, as believe it or not, the NAVGEM was the only model to correctly initialize both relative size and position in the Caribbean Sea. The remaining global models at the same time, initialized this near the Yucatan Channel/Peninsula. IF the NAVGEM is correct, it would be the first time in 3 hurricane seasons.
As far as strength, if we get development, at the moment, the majority of the models seem to keep this as a Tropical Depression, with the CMC GGEM indicating a Tropical Storm.
Based on my analysis of the current wind shear and 200 mb streamline forecast from the GFS, we should begin to see some better signs of development in about 48 hours, as westerly wind shear is forecast to relax, and upper level winds becoming more favorable for development. During this time, an upper level anticyclone is forecast to build over the Yucatan Peninsula / Yucatan Channel area, and move in tandem with the system. The key with this is, the system will have to remain east of 90W or 85W (depending on where and when development occurs) in order for it to take advantage of the upper level anticyclone and favorable conditions. This could allow for development into a Tropical Storm. IF the system stays further west, as indicated by the majority of the models, then I would not anticipate anything stronger than a Tropical Depression. Once something develops and the models have a LLC to latch onto, then I will be able to have a better idea of what we may be dealing with as the models should have better track guidance, along with allowing the wind shear forecast to update for a few cycles, then performing a re-analysis on Sunday. So based on the current unknown, the 18Z Intensity Guidance appears to be good at the moment, except I feel the SHIP model is a little overdone, which has a tendency to happen during initialization.
GFS 72 HOUR 200 MB STREAMLINE FORECAST
Elsewhere, a couple of the global models indicate another possible GOMEX low in about 7 days from now. Right now, given that there are no projected significant height falls forecast over that area, this could be a feedback issue. However, from what we have seen thus far, this early in the season, I will be monitoring the area over the next week.
I will not have another update until Sunday afternoon sometime.
Elsewhere, Tropical Storm formation is not expected during the next 5 days.
Have a blessed day!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST /SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS