PTC 16 / Invest 96L continues to drift to the NW across the Bay of Campeche. Cold cloud tops and some lightning has been noted on GOES 16 data. Some tropical meteorologists and researchers have noted that PTC 16 / Invest 96L looks pretty well put together this morning – and even more-so than Tropical Depression 15.
If PTC 16 / Invest 96L gets a name, it will be Nestor.
From the NHC
SUMMARY OF 1000 AM CDT…1500 UTC…INFORMATION
———————————————–
LOCATION…22.4N 95.7W
ABOUT 140 MI…225 KM E OF TAMPICO MEXICO
ABOUT 620 MI…995 KM SW OF THE MOUTH OF THE MISSISSIPPI RIVER
MAXIMUM SUSTAINED WINDS…35 MPH…55 KM/H
PRESENT MOVEMENT…N OR 355 DEGREES AT 8 MPH…13 KM/H
MINIMUM CENTRAL PRESSURE…1007 MB…29.74 INCHES
At 1000 AM CDT (1500 UTC), the disturbance was centered near latitude 22.4 North, longitude 95.7 West. The system is moving
toward the north near 8 mph (13 km/h). A turn toward the northeast is expected this afternoon or tonight, and a northeastward motion at a faster forward speed is expected on Friday and Saturday. On the forecast track, the system will approach the northern Gulf coast Friday and Friday night.
Maximum sustained winds are near 35 mph (55 km/h) with higher gusts. The disturbance is expected to develop into a tropical or subtropical storm later today or tonight, with slow strengthening then expected through Friday night.
* Formation chance through 48 hours…high…90 percent
* Formation chance through 5 days…high…90 percent
The estimated minimum central pressure is 1007 mb (29.74 inches).
Model data
It is still pretty early for PTC 16 / Invest 96L, but model data is in pretty good agreement for a forecast track.
The forecast track from the NHC follows the model guidance very closely. That should give the people along the northern Gulf Coast a bit more confidence when making preparations for this storm. The center of the storm is forecast to make landfall somewhere along the Florida coast.
The model data for intensity isn’t as ‘lined up’ so to speak. And there is some discrepancy between the guidance.
While most model guidance does show a tropical storm within 48 hours, the strength of the storm is still in question.
And that is normal.
If you’ve been reading forecasts on this site, you know that I love to talk about how ‘we won’t know how strong it will be until it forms’ and we still don’t have anything that has formed… So we can’t really know how strong it will be yet.
The good news is that the storm is only forecast to be over the warm Gulf of Mexico waters for 48 to 72 hours. IT is also going to start to interact will a mid-level area of low pressure currently in south Texas. As that mid-level low swings east, it will likely start to tug a bit at PTC 16 and help to shear it apart, a bit.
Because of that, and other factors, there may be a sharp northern edge to the rain.
Forecast impacts from the NHC and main concerns
LANDFALL: Between Friday night at 7pm and Saturday morning at 7am
STORM SURGE: The combination of a dangerous storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide…
Indian Pass FL to Chassahowitzka FL…3 to 5 ft
Chassahowitzka to Clearwater Beach FL…2 to 4 ft
Surge-related flooding depends on the relative timing of the surge and the tidal cycle, and can vary greatly over short distances. For information specific to your area, please see products issued by your local National Weather Service forecast office.
WIND: Tropical storm conditions are expected to first reach the coast within the warning area by late Friday, making outside
preparations difficult or dangerous.
RAINFALL: The disturbance is expected to produce total rainfall accumulations of 2 to 4 inches this weekend from the central Gulf
Coast and northern and central Florida to the eastern Carolinas, with isolated maximum amounts of 5 inches.
Key messages
1. Dangerous storm surge inundation of up to 5 feet above ground level is possible along the Florida Gulf Coast from Indian Pass to Clearwater, where a Storm Surge Watch is in effect. Residents in these areas should follow advice given by local officials.
2. Tropical storm force winds are likely along portions of the north-central and northeastern Gulf Coast where tropical storm
watches and warnings are in effect. Regardless of the exact track and intensity of the system, these winds will cover a large area, especially east of the center, and begin well in advance of the arrival of the center.
3. Wind and coastal flooding hazards along the U.S. East Coast will be covered by non-tropical watches and warnings issued by local NWS offices, since the system is expected to lose any tropical characteristics after it moves inland along the Gulf Coast.
NHC full discussion
Potential Tropical Cyclone Sixteen Discussion Number 1
NWS National Hurricane Center Miami FL AL162019
1000 AM CDT Thu Oct 17 2019
A complicated weather situation is evolving in the Gulf of Mexico. The circulation associated with the tropical disturbance over the southwestern Gulf of Mexico is getting better defined, and the associated convection is getting better organized. However, a
strong mid- to upper-level trough is moving eastward across southern Texas and northern Mexico, and a frontal system is present
over the northern and northwestern Gulf of Mexico. The ECMWF and GFS models suggest that the trough will spawn a low along the
front, with the tropical disturbance merging with that low. On the other hand, the UKMET suggests the tropical disturbance will become the primary low pressure system. Either way, it is likely that a low pressure area with gale-force winds and at least some tropical cyclone characteristics will move northeastward and affect portions of the northern Gulf coast during the next 36-48 h. Based on this, advisories are initiated on Potential Tropical cyclone Sixteen, and coastal tropical cyclone and storm surge watches/warnings are being issued.
The system should track generally northeastward in the southern portion of the mid-latitude westerlies, and the track model
guidance is in reasonably good agreement through 96 h. The forecast track lies a little to the south of the model consensus, as the UKMET has a somewhat more southerly track. The forecast track brings the system across the southeastern United States between 48-72 h, and then has it moving into the Atlantic east of the mid-Atlantic States.
Gradual strengthening is expected as strong upper-level divergence caused by the trough partly prevails over strong vertical shear. Thus, the intensity forecast calls for gradual strengthening along the lines of that in the global models. It is
unlikely, though, that the system will develop into a classical tropical cyclone. The system is expected to be fully extratropical by 48 h, with gradual weakening expected after that time.
Regardless of the exact evolution of this weather system, portions of the northern coast of the Gulf of Mexico will experience strong winds, locally heavy rains, and storm surge Friday and Saturday. Similar impacts are expected across portions of the Atlantic coast of the southeastern United States Saturday and Sunday.
