The Hurricane Hunters flew out to Invest 91L this afternoon to investigate the system. They found a broad area of low pressure along with tropical storm force winds on the northeast side of the low. However it does not currently have a well defined low level circulation that is needed to classify it as a tropical storm. Once the system organizes and develops that defined low we’ll go directly to a tropical storm. I do believe we will see that process occur tonight or on Monday. As such I expect by this time tomorrow night we’ll have Tropical Storm Bill in the western Gulf of Mexico.
TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT SUN JUN 14 2015
For the North Atlantic…Caribbean Sea and the Gulf of Mexico:
1. Data from an Air Force Reserve Unit Hurricane Hunter aircraft
indicate that a broad area of low pressure has formed in association
with the surface trough and upper-level low over the south-central
Gulf of Mexico. However, the low’s circulation is not well-defined,
and the current shower and thunderstorm activity remains somewhat
disorganized. The aircraft also found a large area of tropical
storm force winds well to the north and northeast of the low.
Upper-level winds are forecast to gradually become more favorable
while this system moves northwestward during the next couple of days
across the western Gulf of Mexico, and a tropical depression or
tropical storm could form during that time. Another Hurricane
Hunter aircraft will investigate this system Monday morning.
Interests in and along the northwestern Gulf of Mexico should
monitor the progress of this system. Regardless of tropical cyclone
formation, tropical storm conditions are possible along portions of
the middle and upper Texas coast and the western Louisiana coast
Monday night and Tuesday. There is also a risk of heavy rainfall
and possible flooding across portions of eastern Texas and western
Louisiana. For additional information, please see High Seas
Forecasts and products issued by your local National Weather Service
* Formation chance through 48 hours…high…80 percent
* Formation chance through 5 days…high…80 percent
Tropical Storm Bill will bring a multitude of hazards to Texas. Landfall looks like it will occur somewhere between Galveston and Corpus Christi on Tuesday. Conditions are not favorable for significant strengthening of this system and I don’t expect this to become a hurricane. Those along the coast along and east of the storm’s track may receive a minor storm surge of one foot to two feet with waves on top of that. Tropical storm force winds of 40 to 50 MPH with higher gusts could create some localized issues with tree and power line damage where the highest winds occur. Both the surge and wind threat will depend greatly on the strength of the storm at landfall along with the eventual track. Those details should become more clear once a defined low level circulation develops and we start getting official forecasts from the National Hurricane Center.
We have two threats that I am pretty concerned about related to Bill. The first is going to be the heavy rain and resultant flooding. With extreme amounts of moisture in place and arriving with Bill we could be talking about a dangerous flood event. Folks that end up under or just east of the storm’s track from the Gulf Coast north into Oklahoma could receive widespread 4 to 7 inches of rain with isolated totals near 10 inches. Much of that could fall in a one to two day period – resulting in a significant threat to life and property due to flooding. The specific rain forecast will depend greatly on the track of the storm.
The second primary threat I’m concerned about is tornadoes to the east of the storm’s track. Tropical Storm Bill will create strong low level wind shear to the east of the storm’s track, even after its well inland and no longer tropical in nature. The result will be the potential for spin up tornadoes in the outer bands of the storm. At this time the greatest tornado threat appears to be across Northeast, East, and Southeast Texas. If the storm’s track shifts further west the Interstate 35 corridor along with North and Central Texas will also face a tornado threat. These tornadoes would likely be short-lived but completely rain-wrapped and fast moving.
I’ll be hosting a live video discussion at 9 PM on our YouTube channel to talk more in depth about Bill and what threats it poses to Texas. Be sure to join me at https://youtu.be/9GU3judH6EA