Ida Still Producing Heavy Rain, Flooding and the Threat of Tornadoes

Bill's Blog

Trop;ical Depression Ida is moving northeast, toward the mid-Atlantic states. The threats now are heavy rain, flooding and tornadoes.

It’s the 4th hurricane of 2021 in the Atlantic Basin. Six other years in satellite era (1966 onwards) have had 4+ hurricanes by August 27: 1966, 1995, 1996, 2004, 2005 and 2020. All but 1966 were hyperactive seasons based on NOAA definition.

cone graphic

* Last year a record 5 named tropical storms/hurricanes moved onshore in Louisiana. A Hurricane Watch has been posted for the Louisiana and Mississippi Coastal areas.

[Image of WPC QPF U.S. rainfall potential]
Click Here for a Printer Friendly Graphic

Heavy rain and flooding is likely, with amounts over 10″ forecast for SE Louisiana. Heavy rain could fall all the way north into the Ohio Valley. The rain from Ida should stay south of West Michigan.

Southern U.S. Radar
[Image of probabilities of 34-kt winds]

Tropical storm-force winds (steady winds of +39 mph) may extend well into Louisiana and Mississippi. The winds will cause considerable damage to trees and power lines.

[Image of cumulative wind history]
Forecast Storm Surge

Here’s forecast storm surge (increase in the water level). Add 15-20 foot waves on top of that and this could cause some real problems. The Louisiana Coast is mostly wetlands, swamps and bayous, unlike the built-up tourist areas with the sandy beaches to the east in Alabama and NW Florida.

time of arrival graphic

* Here’s the estimated arrival time of the strongest winds. The worst of the storm should be Saturday night into Sunday.[Spanish Key Messages]

Key messages about the storm in Spanish

Gulf of Mexico Water Temperatures

Here’s the latest Forecast Discussion, Public Advisory, Forecast Advisory, Links to NWS Forecast Offices in New Orleans, Mobile and Lake Charles, a Louisiana surface weather map. New Orleans NWS Forecast Discussion, New Orleans radar. Link to live webcams in the New Orleans Area. Current weather observations in Louisiana.

Satellite loop of Ida.

Summary of Hurricane Laura that hit Louisiana hard last year at this time. Summary of Hurricane Katrina that hit the Gulf Coast in 2005. Map of oil and gas infrastructure in the Gulf of Mexico. GasBuddy blog.

Active Storms  |  Marine Forecasts 2-Day Graphical Tropical Weather Outlook  |  5-Day Graphical Tropical Weather Outlook

The next tropical storm will be named “Julian” and that storm is already brewing in the Atlantic. After Julian will come “Kate”.

Graph of the Hurricane Season from NOAA

Here’s a graph showing the hurricane season in the Atlantic-Caribbean and Gulf of Mexico. It peaks on Sept. 10 with activity remaining strong through mid-October.

Meteorologists measure the severity of tropical storms with the ACE Index. It combines the duration and strength of each named tropical storm throughout the season. Here’s the ACE Index as of 8/27:

You can see daily updates of the Ace Index at the Colorado State University website.

There have been no hurricanes or tropical storms in the Southern Hemisphere (it’s winter down there and there are fewer tropical storms in the Southern Hemisphere than in the Northern Hemisphere. By far the most active area for tropical storms is the Northwest Pacific. That area had a record low ACE Index last year and is well below average at 68.1 so far this season (thanks partly to La Nina). The other sectors in the Northern Hemisphere have above average ACE, but the Northern Hemisphere (and hence the entire planet) has had below average hurricane/tropical storm activity in 2021.

Number of tornadoes in 2021 compared to average

While I’m at it…here’s the tornado count this year (937) compared to average (1,165). That’s only 80% of average. It’s also been a below average year for tornado fatalities. Worldwide, 56 tornado-related deaths have been confirmed with 28 in China, 13 in the United States, six in the Czech Republic, four in Russia, two in India, and one each in Canada, New Zealand and Turkey. There has not been an EF5 tornado in the U.S. this year – only one EF4 and just 12 EF3 twisters.

So far this year, the U.S. has tracked 41,768 wildfires that have burned 4,822,010 acres. You can compare that to past years here.

Copyright 2021 Nexstar Media Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

Weather Tools