Gulf of Mexico's 94L Close to Tropical Depression Status

A tropical disturbance over the southern Gulf of Mexico (Invest 94L) has grown more organized since Saturday, and appears likely to develop into a tropical depression on Sunday or Monday as the storm heads west-northwest at 10 mph. Satellite loops late Sunday morning showed the disturbance had acquired a well-developed surface circulation, but 94L's heavy thunderstorms were not well organized and were relatively sparse, as seen on Mexican radar out of Sabancuy. Development was being arrested by the presence of high wind shear of 20 knots and a large area of dry air to the west, as seen on water vapor satellite images. Sea Surface Temperatures (SSTs) in the southern Gulf of Mexico are very warm, about 29 - 29.5°C (84 - 85°F), which will help development. An Air Force hurricane hunter aircraft will investigate 94L on Sunday afternoon to determine if a tropical depression has formed.


Figure 1. Latest satellite image of Invest 94L over the Gulf of Mexico.


Figure 2. Predicted total rainfall from 94L from the 00Z (8 pm EDT) Saturday June 18, 2016 run of the HWRF model. The model predicted 94L would develop into Tropical Storm Danielle with top winds of 40 - 45 mph and bring widespread rains of 4 - 8" to the coast of Mexico between Veracruz and Tampico, with a few isolated areas getting more than 8". Image credit: NOAA/NCEP.

Forecast for 94L
Steering currents favor a west-northwest motion for 94L across the Bay of Campeche, with landfall occurring between Tampico and Veracruz, Mexico on Monday afternoon or evening. In this region, 3 - 6" of rain are likely Sunday through Tuesday--with higher rainfall amounts of 4 - 8" with isolated 8 - 12" amounts if 94L ends up developing into a tropical storm. The 8 am EDT Sunday run of the SHIPS model predicted that wind shear would fall to the moderate range, 10 - 20 knots, by Sunday afternoon, giving 94L increased chances of development The Sunday morning operational runs of our three reliable models for predicting tropical cyclone genesis, the European, GFS and UKMET models, all supported development of 94L into a tropical depression; more than 80% of the 70 forecasts from the GFS and European model ensembles showed 94L developing into a tropical depression by Monday. In their 8 am EDT Sunday Tropical Weather Outlook, NHC gave 94L 2-day and 5-day development odds of 70%. If 94L becomes a tropical storm, it would be named Danielle. I don't see heavy rains from 94L reaching South Texas.

Jeff Masters