97L Will Bring Heavy Rains to U.S. Central Gulf Coast Friday and Saturday

October 24, 2019, 1:39 PM EDT

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Above: GOES-16 visible image of 97L at 10:50 am EDT October 24, 2019. Image credit: NOAA/RAMMB.

An area of disturbed weather over the Gulf of Mexico’s Bay of Campeche will bring heavy rains to the central Gulf Coast over the weekend. This disturbance, designated 97L by NHC on Thursday morning, has a 50% chance of developing into a tropical depression or tropical storm. A hurricane hunter aircraft is on call to investigate 97L on Friday afternoon, if necessary.

Thursday morning satellite images of 97L showed an expanding area of heavy thunderstorms that were steadily growing more organized. Winds at buoy 42055, located in the central Bay of Campeche near some of 97L’s heaviest thunderstorms, gusted as high as 38 mph on Thursday morning. Conditions were favorable for development, with wind shear light to moderate (5 – 15 knots), warm ocean temperatures near 29°C (84°F), and a very moist atmosphere with a mid-level relative humidity near 75%. The sea surface temperatures are about 1.5 – 2.0°C (2.5 - 3.6°F) above average for this time of year.

Precipitation forecast

Figure 1. Predicted 7-day precipitation amounts ending at 8 am EDT Thursday, October 31, 2019. Image credit: NOAA.

Forecast for 97L

97L was headed to the north-northwest at about 10 mph on Thursday morning. By Friday, a trough of low pressure over the central U.S. will force 97L on a more north-northeasterly track, and will begin funneling moisture from the disturbance into Louisiana, eastern Texas, Mississippi, Alabama, and the Florida Panhandle. This system will likely spread rain farther northeastward into the Mississippi and Tennessee Valleys Friday evening into early Saturday, with a widespread region of 3 – 5” of rain likely. Another heavy dose of rain is expected across the region next week, which could push 7-day rainfall totals into the 5 – 7" range (see Figure 1).

As 97L approaches the U.S. Gulf Coast on Friday, wind shear will increase and dry air will invade the Gulf system from the north. By Friday night, the SHIPS model predicts that wind shear will rise to a prohibitively high 30+ knots, so 97L has a short window of opportunity for development, and the disturbance has relatively weak support for development into a tropical cyclone from our top computer models. In a special 9:50 am EDT Thursday Tropical Weather Outlook, NHC gave 97L 2-day and 5-day odds of development into a tropical cyclone of 50%. The next name on the Atlantic list of storms is Olga.

Tropical depression forms off the west coast of India

The India Meteorology Department (IMD) stated that a tropical depression had formed at 3 UTC October 24 off the west coast of India. The Joint Typhoon Warning Center (JTWC) had yet to classify the system as a tropical depression as of 11 am EDT Thursday, though. IMD predicted that the new depression would move slowly towards India through Friday morning, then reverse course and head west towards Yemen and Oman, intensifying to Category 1 hurricane strength on Saturday. The 0Z Thursday runs of the GFS and European models predicted that the cyclone would be very near the coast of Oman by Tuesday. The next name on the list of storms for the northern Indian Ocean is Kyarr.

Also of interest today is a warm-core "Medicane" that may be forming in the southeast Mediterranean Sea; see the tweets below.

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.

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Dr. Jeff Masters

Dr. Jeff Masters co-founded Weather Underground in 1995 while working on his Ph.D. in air pollution meteorology at the University of Michigan. He worked for the NOAA Hurricane Hunters from 1986-1990 as a flight meteorologist.


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