97L Not A Tropical Cyclone Yet
Another update on Invest 97L currently in the tropical Atlantic. Over the past 24 hours, convection has been trying to consolidate towards the center mass of the system but has failed to do so. This is not unusal as it has entered into a region of high wind shear. Aircraft recon was conducted this afternoon and found no closed center of circulation. Given this finding, no tropical depression or tropical storm classification will be issued at this time. The aircraft recon sent the following vortex message:
URNT12 KWBC 241133
VORTEX DATA MESSAGE AL122016
A. 24/10:58:50Z
B. 32 deg 04 min N
063 deg 49 min W
C. NA
D. 40 kt
E. 119 deg 48 nm
F. 206 deg 57 kt
G. 121 deg 65 nm
H. 995 mb
I. 15 C / 2353 m
J. 19 C / 2353 m
K. 11 C / NA
L. NA
M. NA
N. 1345 / NA
O. 0.1 / 1 nm
P. NOAA3 WJ12A KARL OB 17
MAX OUTBOUND FL WIND 59 KT 086 / 59 NM 11:14:36Z
MAX FL WIND 63 KT 092 / 64 NM 10:28:30Z
CENTER DROPSONDE SFC WIND 015 / 8 KTS
DETERIORATING RADAR PRESENTATION IN CENTER
CONVECTIVE ORGANIZATION DECREASING
For those unfamiliar with these messages I will elaborate on the sections in bold. First, D, the recon found maximum wind speed estimates around 40kts (46mph) which is the same wind speed for a tropical storm. Once a closed center of circulation is established I expect that Invest 97L will skip tropical depression status and become Topical Storm Matthew (as long as wind speeds don’t decrease before that time).
Next, H, this is the minimum central pressure according to dropsonde data collected. This is impressive for a tropical system like this and would confirm my suspicions on potentially being a tropical storm upon finding a closed circulation.
Last, the description at the bottom of the message. This message is something that has been noticed from satellite images but confirmed from within the storm. With “deteriorating radar presentation in center” and “convective organization decreasing” this also indicates that the storm isn’t producing as much centralized convection as earlier. This goes back to my opening where I mentioned this very point. In situations like this, you would like to see convection above the center of the storm. This convection would contribute to the strengthening of the system and most likely form a closed circulation quicker. This doesn’t mean that this system is weak. As the vortex message indicated above, surface winds are at 46mph which is equivalent to tropical storm force winds. If you are in the path of this system, even if it isn’t called a tropical storm, you will see the same effects as a tropical storm.
Its future has been complex from the beginning and continues to be difficult to forecast. What is making this so difficult is the presence of a cutoff upper-level low which will travel over the Atlantic Seaboard. This will create a weakness in the strong ridge to the north which would allow a turn to the north.
Before we get there it still has a couple of days to get through the southern Caribbean. During this time it is most likely going to strengthen into a tropical storm or even a hurricane. If it takes a more southern path it will begin to interact with South America. The geography and topography make it difficult for a tropical cyclone to strengthen or may even cause some weakening.
It should survive its interaction with the continent and will move into a more favorable environment for strengthening. The limits on its strengthening is going to be minor and forecast intensities range from Category 1 to 3 hurricanes. These forecast might end up being raised or lower but these numbers aren’t unreasonable.
Now this is where the trough comes into play. The weakness in the ridge is forecast to be far enough south to influence the track of the storm. The models are similar with a rapid turn to the north once it reaches this weakness but the timing and placement of this trough is very important and where it turns becomes very important.
Some possibilities include a more westerly position of the trough. This would result in a later turn to the north and place the track over western Cuba where it would emerge off the coast close to the western side of the Florida Peninsula. The strength at impact in Florida would be determined by its interaction with Cuba and its terrain.
Another possibility is the trough remains where it is currently forecast to be and the storm makes the northward turn earlier tracking it along the east coast potentially making landfall over the North Carolina Outer Banks (or very close).
If the trough is further to the east, the storm turns even earlier and rides the trough well off the coast and out to sea.
In every scenario presented, this could very well be a hurricane in each. Watching this storm will take a lot of time since the first potential encounter with the US will occur early next week.
If you live from Florida to the northeastern US, make sure you are prepared if it does head your way. Make sure you have everything you will need in the event of a landfall and have an evacuation plan in place in the event that one is needed. If you live along the Gulf Coast, you are not out of the woods yet. Careful attention will need to be made over the next few days as we begin to get a better picture of where this storm might head.
Below are some of the forecast models for this storm. Do not concentrate on one model alone. This image gives you an idea of how wide the uncertainty is.
Continue to check back for further updates regarding this situation.
A special note: The information presented in this forecast are not an official forecast from the NHC or NWS. It is an opinion forecast based on my years of study and application. I do not represent a public or private institution and in the event of an emergency, consult with the NHC or other local officials and do not make any life or death decision based solely on the information from this site.