8/26/19 Update: Tropical Storm Dorian key messages from NHC with model data

Author: || Published: 8/26/2019 at 10:47pm

As of 11:30p CDT, Tropical Storm Dorian continues to try to organize itself.

8/26/19 11:30pm Infrared Imagery of Tropical Storm Dorian // Courtesy: College of DuPage Meteorology

Here is the latest forecast graphic from the NHC:

Courtesy: nhc.noaa.gov

Latest on Tropical Storm Dorian (10p CDT) has it slightly weaker than original satellite-based estimates. Take a look at the estimated wind field:

8/26/19 Experimental wind field estimation at 10p CDT // Courtesy: http://rammb.cira.colostate.edu

Tropical Storm Dorian continues to churn through Windward Islands and into the Caribbean. Latest Hurricane Hunter data suggests that Dorian may not be as strong as originally estimated.




Key Messages

SUMMARY OF 1100 PM AST…0300 UTC…INFORMATION
———————————————–
LOCATION…13.2N 59.7W
ABOUT 95 MI…155 KM ESE OF ST. LUCIA
MAXIMUM SUSTAINED WINDS…50 MPH…85 KM/H
PRESENT MOVEMENT…WNW OR 290 DEGREES AT 13 MPH…20 KM/H
MINIMUM CENTRAL PRESSURE…1003 MB…29.62 INCHES

Courtesy: nhc.noaa.gov

Key Messages:

1. Dorian is expected to bring tropical storm conditions to portions of the Lesser Antilles through Tuesday morning, where tropical storm watches and warnings are in effect. Rainfall of 3 to 8 inches is expected from Martinique to St. Vincent, including Barbados, with isolated totals as high as 10 inches possible.

2. Tropical storm conditions are possible in Puerto Rico on Wednesday, where a tropical storm watch has been issued. Rainfall of 2 to 4 inches with maximum totals of 6 inches are possibleacross Puerto Rico and St. Croix.

3. Watches will likely be issued for portions of Hispaniola early Tuesday, as the threat of wind and rain impacts continues to increase.

4. While uncertainty is high, wind and rain impacts are possible in the Bahamas and Florida later this week and this weekend. Residents in these areas should monitor the progress of Dorian and ensure that they have their hurricane plan in place.




Model Data

Full transparency here: The reliability of model data is likely going to be higher in the coming days as the Hurricane Hunter data continues to get dumped into the algorithms of the modeling. That said, here is a quick look at the data we have available tonight…

12z ECMWF Ensemble

The Euro ensembles really grabbed the attention of a lot of people today.

The reason for the extra chatter today was the shift in the number of members of the ensemble leaning toward Florida instead of out to sea. But that doesn’t guarantee Dorian is going to hit Florida. Again, as we continue to get Hurricane Hunter data in the coming model runs, we should start to get a much better idea about where this system is going.

Now, if this trend continues – even with the new data – then it is cause for heightened concern.

On thing that Brad Panovich posted earlier today was a look at Dorian from a few different “angles” of atmospheric parameters.

8/26/19 12z Multi-model view of Dorian // Courtesy: http://rammb.cira.colostate.edu

Earlier today, Dorian was at a point of lowest shear in the foreseeable forecast time frame. That means it should’ve had the easiest time – shear-wise, at least – getting organized. The only problem was, at the same time it was also battling the highest level of dry air. So, that may have been one reason for the difference between the estimated strength an actual strength.




More from the NHC

Tropical Storm Dorian Discussion Number 11
NWS National Hurricane Center Miami FL AL052019
1100 PM AST Mon Aug 26 2019

via GIPHY

An Air Force Reserve Unit Hurricane Hunter aircraft has been investigating Dorian this evening. Data from the plane indicate that the storm is not quite as strong as previously estimated, and based on flight-level winds and SFMR-observed surface winds the intensity is set at 45 kt. Fixes from the aircraft show that the center of the cyclone moved just south of the southern coast of Barbados within the last couple of hours, and tropical-storm-force winds were reported over that island. There is fairly well-defined upper-level outflow over the eastern semicircle of the circulation. Although some dry mid-level air is likely to continue to affect Dorian while it moves over the northeastern Caribbean, the dynamical guidance indicates that the shear will not become very strong. Therefore it is still expected that the cyclone will become a hurricane in a couple of days. Some disruption of the system will likely occur when the center moves near eastern Hispaniola. The official intensity forecast is on the high end of the model guidance and is subject to considerable uncertainty, particularly from days 3 to 5.

Courtesy: nhc.noaa.gov

Dorian continues to move west-northwestward, or 290/11 kt, while being steered by the flow on the south side of the subtropical ridge. In a day or two, the tropical cyclone is expected to turn northwestward due to a weakness in the ridge. The ridge is expected to build somewhat later in the forecast period, which should cause Dorian to turn slightly to the left. The ECMWF model is near the northern side of the guidance suite and the UKMET is near the southern side. The GFS model continues to practically dissipate the system so it was unable to generate a forecast track. The official track forecast was shifted a bit to the north, but lies south of the latest dynamical model consensus. It is advisable that one not focus on small changes in the forecast track due to uncertainties.

Bottom Line

Right now – unless you are reading this from the Windward Islands – we are in a wait-and-see position. Circling the airport, so to speak. For Gulf Coast folks, as I mentioned tonight on the 10p news, we may have to wait until Thursday evening before we get a better idea about what it means for the Louisiana, Mississippi and Alabama region.

So for now, check your Hurricane Preparedness Kit, Check your supplies, make sure you have a plan. But outside of that, just hang tight!




Author of the article:


Nick Lilja

Nick is former television meteorologist with stints in Amarillo and Hattiesburg. During his time in Hattiesburg, he was also an adjunct professor at the University of Southern Mississippi. He is a graduate of both Oregon State and Syracuse University that now calls Houston home. Now that he is retired from TV, he maintains this blog in his spare time.