INVEST 91L IN SOUTHERN GULF MAY BECOME TROPICAL STORM IN GULF; LOCAL IMPACTS POSSIBLE… Higher rain chances are likely by midweek as a tropical disturbance moves near or directly over our local area, potentially as a tropical storm. The National Hurricane Center continues to indicate a low-end (30%) chance of this disturbance, currently branded as Invest 91L, developing into a tropical storm. Regardless of if this system becomes a named storm (next name: Mindy), deep moisture from the tropics will be moving into our local area by midweek. This means that higher rain chances are likely Wednesday into Thursday, perhaps even extending into Friday under some scenarios. Unfortunately, due to a wide spread in model guidance, it is too early to know if a tornado risk or risk of gusty winds will happen at the Alabama or northwest Florida beaches. Before we get to the potential for more tropical impacts later this week, we have a nice Sunday on tap in most spots. Low (10-20%) rain chances are likely today with high temperatures in the low-90s. This special Sunday edition of the RedZone Weather morning discussion highlights everything you need to know regarding the tropics and our local weather forecast, below.
FEW SHOWERS & STORMS NEAR COAST TODAY… Just like what happened yesterday, vast majority of our communities across south Alabama and northwest Florida will remain dry today. A few showers and thunderstorms may bubble up near the Alabama and northwest Florida beaches this afternoon into this evening. Rain chances remain in the 10-20% range today. These storms will primarily develop in areas along and south of Interstate 10. High temperatures this afternoon will be in the 89-93° range.
DISTURBANCE CENTERED NEAR YUCATAN… The tropical disturbance in the Bay of Campeche region of the southern Gulf of Mexico is broadly centered near the Yucatan Peninsula of Mexico. There is no low-level center of circulation, and thunderstorm activity remains highly disorganized. This means the system is “a mess” this morning. Nearly all weather models show the system remaining paltry and weak through Tuesday due to a hostile upper-level wind environment in the atmosphere over the system.
RANGE OF SCENARIOS; MOST POINT TO HIGHER RAIN CHANCES LOCALLY… We have quite a bit of forecast uncertainty (explained in detail in a paragraph below) with Invest 91L and what ultimately will happen with this system. I have found that it is sometimes good to give a worst case scenario, best case scenario, and a most likely scenario. These are current as of Sunday morning, September 5. Keep in mind these reasonable scenarios can and will change in the days ahead as more data comes in. These scenarios are outlined below:
Reasonable Worst Case Scenario: Weak to moderate (40-65 mph max. winds) tropical storm moves inland along the northern Gulf Coast with a landfall point somewhere from Intracoastal City, Louisiana eastward to Apalachicola, Florida. A few tornadoes happen locally. Heavy rain and flash flooding become likely with total rain amounts of 4-6” being likely. Gusty winds would be likely near the immediate coastal zones, but not inland. Minor coastal flooding may be possible.
Most Likely Scenario: Invest 91L moves north across the Gulf of Mexico today, tomorrow, and on Tuesday. The system becomes a tropical depression or a minimal tropical storm. Deep tropical moisture is transported into our local area in south Alabama and northwest Florida from the south, causing heavy rain at times Wednesday, Thursday, and Friday, particularly in areas closer to the coast. A risk of a few tornadoes may set up locally, depending on the exact future track of the system. Gusty winds may happen at the immediate beach zones. High wind impacts not expected inland.
Reasonable Best Case Scenario: Invest 91L is not able to develop into a tropical storm and, instead, dissipates. Tropical moisture streams into our area from the south Wednesday, Thursday, and Friday, causing higher rain chances.
FACTORS LIMITING RAPID DEVELOPMENT… For folks that may be concerned about this system ramping up quickly into a powerful storm, let me try to give you some calming information. This environment is a much different situation compared to what happened with Hurricane Ida just last week. The upper-level wind environment likely will be quite hostile to a tropical storm attempting to develop this week. Invest 91L will likely be a highly sheared system that is rather small and rather lopsided in nature, with most (if not all) of the more significant impacts happening on the eastern side of the storm. In addition, sea surface temperatures (SSTs) ARE warm, but not AS warm as the untapped Gulf environment that was ahead of Hurricane Ida. Even a small difference in SSTs could prevent this storm from developing into a named storm considering how hostile the upper-level environment will be.
FORECAST UNCERTAINTY; PLEASE CHECK BACK FOR UPDATES… Unlike Hurricane Ida that featured extraordinarily high forecast confidence, this system is a bit different. Right now, the system remains disorganized, thus models do not have a firm grip of where a low-level center of circulation may develop in a few days in the northern Gulf. In addition, because it isn’t known where a low-level center will form, that makes it tough to forecast where impacts like heavy rain and tornadoes may happen. These compounding bits of uncertainty in the forecast underscore the need to check back in for updates ever the next few days. I suspect forecast confidence will begin to increase Tuesday once we have a better handle on the system in the central or northern Gulf.
HURRICANE LARRY IN THE ATLANTIC… Hurricane Larry remains a powerful, category 3 hurricane in the open waters of the central Atlantic Ocean this morning. The center of the large, ragged eye associated with Larry is located about 910 miles east of the Lesser Antilles or about 1,440 miles southeast of Bermuda. Hurricane Larry may cause some impacts in Bermuda, particularly high waves, midweek. Direct impacts in the USA, other than high waves at the Atlantic beaches, are not expected as Larry remains well to the east of the continental U.S.
APP ALERTS… If you haven’t already, be sure to download the free RedZone Weather app to keep up with all the latest information on the world of weather in south Alabama and northwest Florida. redzoneweather.com/app is the link for the free download. Once you have the app downloaded to your iOS or Android device, be sure to visit the Alerts tab (lower right corner) and tap the large, yellow Alert Settings button to customize the alerts you would like to receive straight from me.
I will be posting updates throughout the day on this Sunday as needed in the RedZone Weather app. If we have any significant forecast changes to pass along, I’ll be sure to send out a Low-Level Alert or Medium-Level Alert in the app. Have a nice Sunday!
