Tropical Soaking Ahead For Alabama

An all new edition of the ABC 33/40 Weather Xtreme video is available in the player on the right sidebar of the blog. You can subscribe to the Weather Xtreme video on iTunes by clicking here.

Be sure and watch the afternoon Weather Xtreme video for all of the graphics that go along with this discussion….

New NHC track just out…

RIGHT NOW: Most of Alabama is rain-free, although the first feeder bands of Isaac have moved into the southeast part of the state. From here on this, our weather will be determined by Isaac.

ISAAC NOW: A new NHC update will be issued soon, probably by the time you read this, and it could be a minimal hurricane. It is certainly close now with sustained winds of 65 mph. Isaac is moving NW at 14 mph.

TRACK: We are now very confident that Isaac will move into Southeast Louisiana, around the mouth of the Mississippi, tomorrow, followed by a recurving track through Louisiana and Arkansas with gradual weakening as the system moves inland. Don’t expect much change in this between now and time of landfall. Alabama will be on the wet, unsettled side of the circulation (the east side).

INTENSITY: Three things I believe have prevented Isaac from growing stronger rapidly… dry air (clearly seen on the southern and eastern sides now on satellite images), the large nature of the circulation (it needs to be smaller and tighter for rapid deepening), and the shallow nature of the warm Gulf of Mexico temperatures. The SSTs are pretty warm, but the warm water is not very deep. Accordingly, I think NHC is correct in showing Isaac as a category one hurricane at the time of landfall.

COASTAL ISSUES: No, there won’t be major structural damage with a category one hurricane, but I do think there will be some power outages along the Gulf Coast, especially from New Orleans over to Orange Beach, with some potential for downed trees from the gradient wind. A few tornadoes are possible from New Orleans all the way around to Apalachicola tomorrow as Isaac makes landfall.

But, the biggest issue to me is the potential for flooding. NHC suggests a 6 to 12 foot storm surge will effect the MS/AL Gulf Coast late tomorrow, which means some coastal flooding. No, nothing like Ivan or Katrina, but still this is significant.

And, the rains will be tremendous. Guidance shows a very slow motion through Louisiana, and some of the QPF charts are showing rains of 10 to 20 inches over the next 72 hours for places like Gulfport, Biloxi, Mobile, Daphne, Foley, Gulf Shores, and Orange beach. Flooding, most likely, will be the biggest problem associated with Isaac for the Gulf Coast. Conditions will slowly improve by Thursday along the coast.

UP THIS WAY: Let’s go to bullet points….

*POWER OUTAGES? I don’t think the gradient wind will enough over North/Central Alabama for major tree damage, or widespread power outages. No doubt it will be breezy tomorrow night into Wednesday, with south winds of 15-25 mph, but that isn’t enough to really cause serious issues. We are not recommending that people in mobile homes leave.

*FLOODING POTENTIAL: With the slower motion, I now think the heaviest rain here will come Wednesday, and possibly into the day Thursday. For the I-20/59 corridor (Tuscaloosa, Birmingham, Anniston, Gadsden), rain amounts of 3 to 5 inches are likely, with lighter amounts up north over the Tennessee Valley. Not sure we see all that much flooding around here, but it is possible.

The most significant flooding threat for inland areas of Alabama will come over the southwest part of the state, generally south of a line from Livingston to Demopolis to Greenville and south to Andalusia. This part of Alabama could see 5-12 inches of rain through Thursday.

*TORNADO THREAT: I do believe a few small, isolated tornadoes are possible across North and Central Alabama Wednesday and Thursday. Remember, the tornadoes in spiral bands around a decaying tropical system tend to be small, short lived, low topped, and hard to detect. They are not like the truly violent tornadoes we see in spring or fall, but that can produce significant damage, and the NWS does issue tornado warnings if they believe one has formed. So, be close to a good source of severe weather information this week in case warnings are needed.

*TRAVEL: I believe incoming and departing flights from Birmingham-Shuttlesworth Airport will not be hampered too much by Isaac, but there might be a ground stop or two along the way in event of torrential rain, or a tornado warning. If you are flying to the Alabama/Michigan game in Dallas this week you should be able to get there just fine, although your flight from Birmingham might be delayed a bit.

If you are driving somewhere by car, just be aware of the flooding potential; that is the biggest concern. And, be sure you can hear tornado warnings if they happen to be needed.

*SCHOOL CLOSINGS? I honestly don’t think they will be needed, but if the flooding threat becomes more serious that could change.

*LABOR DAY WEEKEND: Isaac will be long gone by the holiday weekend, so it won’t interfere with a beach trip. But, very tropical air rich in moisture should linger across the Deep South, meaning you will have to dodge at least scattered showers and storms through Monday with a fairly limited amount of sunshine each day.

WEATHER BRAINS: Don’t forget you can listen to our weekly 90 minute netcast anytime on the web, or on iTunes. This is the show all about weather featuring many familiar voices, including our meteorologists here at ABC 33/40. We will produce this week’s show tonight at 8:30 as usual… you can watch it live here.

CONNECT: You can find me on all of the major social networks…

Facebook
Twitter
Google Plus

Stay tuned to the blog for running updates on Isaac through the week. Also, thanks to my friends at the Walker County ARC in Jasper for allowing me to drop by for a while today. They were great audience.

Look for the next Weather Xtreme video here by 7:00 a.m. tomorrow…

Tags: Isaac

Category: Alabama's Weather