Debby Dissipates; Tropical Outlook for July
After over 5 days of tormenting forecasters everywhere, Tropical Storm Debby dissipated just off the east coast of Florida as of the 5PM advisory from the National Hurricane Center. Debby proved to be one of the greatest forecasting challenges of all time, particularly in its track forecasts, as models struggled to agree on a Florida or Texas landfall. In the end, the GFS model performed the best by far, as it was the only model to consistently bring Debby into Florida. Intensity forecasts were tricky also, mostly because of changes in the track forecast. Original predictions for Debby to become a hurricane fizzled, and she peaked with winds of 60mph. Debby's biggest impact by far was torrential rainfall across Florida, with some amounts exceeding 30 inches in localized areas. This triggered serious flooding.
Figure 1: Remnants of Debby
Figure 2: Tropical Storm Debby turned roads into rivers in Florida. (Photo courtesy of USA Today)
Debby's remnants are located over a marginal environment for restrengthening. Some models do redevelop the system, and the NHC has indicated this as a possibility in its 5PM advisory. I do not personally see Debby redeveloping.
Outlook for July
At this point it appears unlikely we will see anymore development in June as we approach the end of the month. A tropical wave is currently located about 1500 miles east of the Windward Islands. It is being given a 10% chance of development in the next 48 hours by the National Hurricane Center. I do not foresee development of this disorganized system, and I give it a near 0% chance of developing in the next 48 hours.
Figure 3: 8PM TWO from the NHC, showing the small, disorganized wave mentioned
Looking out farther, it appears the Atlantic will be very quiet during the month of July. The main reason for this will be the loss of the MJO that helped form Tropical Storm Debby. Having the MJO is key to development before August. In addition, wind shear is high in the Caribbean where we would typically look for development this time of year.
Figure 4: Atlantic wind shear map.
These factors will make it difficult to get any storms of truly tropical origins through at least July 20. It is much harder to predict storms of non-tropical origins like recent Hurricane Chris. I think we will probably see one of these at some point this month, so I believe we will see Ernesto in July. With El Nino approaching, August is the month to watch this year as activity will mostly shut down by the end of September. At this point a total of 11-13 named storms still seems likely at this point.
Tropical Storm Dukshuri is currently drenching the northern Philippines. It currently has winds of 40mph, and slight strengthening is forecast as it heads towards a final landfall near Hong Kong Friday or Saturday. Heavy rains will be the biggest concern.
Figure 5: Tropical Storm Dukshuri. The deepest convection is well west of the center.
I've mentioned this on Dr. Master's blog a couple times this week, but I'll mention it again here. It's been my pleasure to work at the Blue Hill Observatory in Milton, Massachusetts over the past two days. Home of the oldest set of continually recorded weather data in North America, it's truly an amazing facility and it's an honor for me to work there this summer. I contributed in the writing of the daily discussion today, which you can find here. My name is Jonathan (there's a typo in the discussion, it's spelled Jonathon there instead of Jonathan). I wrote it with the Observatory's chief observer Mr. Robert Skilling, who has worked there for over 50 years.
Thank you as always for reading, and have a great rest of your week!