Archive for August 23rd, 2012
Isaac More Of A Threat To The Central Gulf Coast
The new model set tonight has shifted west…
And, the new NHC track just in brings Isaac to near Mobile Bay Tuesday night…
Below is the discussion from the Friday morning forecast package just posted over on the seven day page. I will have a new Weather Xtreme video and blog discussion up here by daybreak tomorrow. Stay tuned…
ISAAC MORE OF A THREAT TO THE CENTRAL GULF COAST: Quite a challenging forecast this morning with potential for a Gulf of Mexico hurricane in coming days. But, in the short term Alabama’s weather will remain quiet with mostly sunny days and fair nights through the weekend. Humidity levels will slowly rise, and we will mention a small risk of a shower tomorrow and Sunday, but most places should remain dry. Then, next week, our weather will all depend on the track of Isaac.
THIS MORNING: Isaac is still a disorganized, weak tropical storm in the Caribbean south of Hispaniola. The circulation center has been reforming to the south over the past 24 hours, and position more to the south over the Caribbean will mean a threat to the Gulf Coast more to the west than initially thought. Isaac will move over Cuba tomorrow, and should emerge into the southern Gulf of Mexico Monday morning. Isaac is expected to remain well below hurricane strength this weekend due to the interaction with Cuba.
NEXT WEEK: Computer models have shifted to the west, and most show a potential landfall on the Gulf Coast somewhere between the mouth of the Mississippi River and Panama City Tuesday or Wednesday. Unfortunately, it looks like conditions are favorable for Isaac to not only to grow into a hurricane, but potentially a dangerous hurricane due to high ocean heat content and a favorable upper air pattern. Isaac will be crossing the warm loop current over the Gulf, and could spin up in a hurry. However, there is little skill in forecasting hurricane intensity five days in advance.
CALL TO ACTION: Keep in mind the forecast track could very well change again, it is still early in the development stage with Isaac, but based on model trends, we advise those that live on the coast from New Orleans to Dauphin Island to Gulf Shores to Destin and Panama City to begin preparations for a hurricane as a course of least regret. Get a readiness kit together now, and think about where you will go if an evacuation is needed at some point next week.
NORTH/CENTRAL ALABAMA: We will go ahead and increase the chance of rain here, along with increasing wind on Wednesday. We simply don’t have enough confidence in the forecast track of Isaac to forecast any specific rain amounts here, but there is potential for a heavy rain/flooding event at mid-week if we wind up on the wet side (the east side) of the storm circulation.
Isaac, And Model Madness
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.
LET THE FUN BEGIN: Much uncertainty has now been introduced in the future track of Tropical Storm Isaac with a westward shift in the 12Z model runs. Let me say this up front… a NOAA Gulfstream IV research aircraft is in the region this afternoon gathering detailed upper air data that should be ingested in the 00Z model runs tonight, which should bring more clarity to the situation. I think the 00Z and 12Z Friday runs will tell a much clearer story.
THE ISSUE: Isaac now is a very disorganized storm, and it has been hard really getting the exact circulation center nailed over the past 24 hours. But, simple satellite observations suggest the circulation center is displaced to the south over the Caribbean, and this new initialization has led to the westward adjustment in the 12Z model runs.
So… there are more questions than answers now, and we really need to see the 00Z and 12Z runs with the Gulfstream upper air data before totally jumping on the westward shift. Take some time to watch the Weather Xtreme video for the graphics and complete details.
Here are the afternoon talking points on Isaac…
*With a system more to the south, that means there will be less interaction with Hispaniola, and a better chance of intensification over the next 24 hours over the Caribbean.
*Isaac will still have to move over Cuba, but this won’t take long, and the system should emerge into the Southeast Gulf Monday morning as a hurricane.
*If indeed the track more to the west is correct, there is plenty of latent heat energy available along with high SSTs, which would increase the chance of Isaac becoming a significant hurricane early next week on the journey northwest. Remember, there is little skill in forecasting hurricane intensity 5 days in advance. But, a major hurricane is a very real possibility without the interaction with Hispaniola and if the system stays west of the Florida Peninsula. And, that is still a big IF.
*The ECMWF, which has been horrible with tropical systems this summer, remains an outlier to the west; it tries to take Isaac to near the Sabine Pass (the TX/LA border), and that is rejected. The NAM remains the outlier to the east as it keeps Isaac east of Florida. Most of the tropical models, and the GFS ensembles, are now pointing to the Florida panhandle. But, is is very important to note that this not a forecast… just model output. There isn’t much skill in getting a hurricane track correct beyond five days; this is just guidance for planning purposes. The models can shift just as easily to the east over the next 24 hours.
*Having said all of that, a small window is opening for a possible impact on the Central Gulf Coast in the Tuesday-Wednesday time frame next week. I still believe the greatest threat is east of Panama City, but everybody as far west as New Orleans will now need to pay attention. And, if the west track is correct, Isaac could be a very significant hurricane. The east track, which I still believe is more correct, would mean a weaker system and much more rain for the Florida Peninsula, and little impact on the Alabama Gulf Coast. One way or another we will have some long days ahead in weather offices across the Southeast U.S.
*In terms of the inland impact over North and Central Alabama, we will assume for now the main rain shield will remain east of here, but with the westward adjustment just be aware that that could change in a big way over the next 24 hours.
BOTTOM LINE: We will be able to provide a much higher confidence track/intensity forecast of Isaac tomorrow, but for now anybody from New Orleans to Key West could be impacted. The exact impact where you live is simply yet to be determined.
Below is the new NHC track just released…
OUR SHORT TERM FORECAST: No real change in our weather through the weekend; generally dry with mostly sunny days and fair nights. Highs around 90 with slowly rising humidity levels. The weather next week all depends on Isaac.
BEACH WEATHER: Great weather for the Central Gulf through Sunday… about 7 to 9 hours of sunshine each day with just a few widely scattered showers or storms. Highs 87-90; the sea water temperature at the Dauphin Island Sea Lab this afternoon is 85 degrees. The weather beyond Sunday all depends on Isaac.
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.
CONNECT: You can find me on all of the major social networks…
Look for the next Weather Xtreme video here by 7:00 a.m. tomorrow…
Another Cool Morning
Remember, we still have September down the road. That month can be very hot. On September 5 and 6, 1925, it was 106 in Birmingham–two of seven days in a row with 100 or higher! Later that month, there were two more 100+ days. As if Mother Nature was trying to rub it in, two years later, in September 1927, Birmingham suffered through five more days with 100 or hotter.
By the way, on September 5, 1925, when Birmingham had 106, down the road in Bibb County, Centreville recorded an official 112–the hottest ever for all of Alabama!.
Enough of that!
Let’s back up until this morning and celebrate a few more cool “getting-up-time” lows. Remember, these are for the 24 hours ending around 6 or 7 am and some of these could have been recorded at 6:01 yesterday morning but most were this morning. NOTE: Because of continuing computer problems, I have been unable to download reports from the ABC 33/40 Skywatchers. Those are some of the best reports. Still working on the problem.
59 Anniston and Huntsville
55 Fort Payne
61 Albertville
58 Cullman
60 Courtland
56 Crossville
64 Guntersville
56 Scottsboro
54 Valley Head and Hamilton
60 Alexander City
58 Centreville
53 Sylacauga
62 Birmingham
63 Tuscaloosa
Air conditioning was virtually unheard of. I know of one farmer, in West Alabama, that planted sprigs of kudzu on the south and west sides of his house to shade out the hot sun. It soon covered his entire house and he had to chop away an opening to his front door to get in and out!
How lucky we are!
Dry Pattern For Alabama Continues
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.
SUNNY DAYS: Before we get into the details on Tropical Storm Isaac, we need to point out that our benign weather pattern will continue for the next 5 to 7 days with little in the way of significant rain opportunities here. Afternoons will be a little warmer, with a high around the 90 degree mark through early next week, and humidity levels will rise a bit as well. Still, nothing too hot for August.
TROPICS: Tropical Depression 10, the system east of Isaac, will be a higher latitude storm, and should recurve before reaching the U.S. It could become Tropical Storm Joyce along the way, and could be close to Bermuda early next week, but any U.S. impact is very, very unlikely.
Remember, take a little time to watch the Weather Xtreme video for all of the graphics and details that go along with this discussion….
EYES ON ISAAC: Isaac remains a very disorganized and weak tropical storm, with sustained winds of only 40 mph this morning. It is finally slowing down a bit, which should help it get better organized, but interaction with Hispaniola and Cuba will most likely keep this a fairly minimal tropical storm in the short term.
We should point out it will produce very heavy rain across the Dominican Republic and Haiti, and serious flooding issues will be possible there.
Here are our Thursday morning bullet points…
*Isaac will not be able to really intensify until it clears the northern coast of Cuba, and should not be a major, destructive hurricane when it impacts the Florida Peninsula.
*There is actually pretty decent model agreement in the track. The ECMWF remains the outlier to the west, showing a landfall near Pensacola (but it has shifted east), and the NAM remains the outlier to the east, keeping Isaac east of Florida. The 00Z GFS ensembles look good; the system will run from near Key West north, near the Florida West Coast, or perhaps just offshore in the far eastern Gulf, with a landfall somewhere around Apalachee Bay Tuesday.
*Remember, the heaviest rain will be on the east side of the circulation, and this track puts much of the Florida Peninsula (NOT the panhandle) in a position to receive soaking, tropical rains that could lead to flooding. Places like Miami, Orlando, Tampa, Daytona Beach, and Jacksonville will be soaked in the Monday-Tuesday time frame.
*The amount of intensification will all depend on the track. If Isaac’s center is over the far eastern Gulf, it could strengthen pretty quickly, but if the center remains inland over the peninsula it will have a hard time. One way or another, I still believe the main threat is from heavy rain and flooding, but we will have to watch for any surprise intensification. The ability to forecast intensity of tropical systems is not good 5 days in advance.
*Alabama stays on the dry side, and for this part of the state our weather looks mostly dry next week. The far southeast part of the state, in the general area from Eufaula to Dothan, could see some rain from Isaac, but even that is “iffy”.
*I do not expect any really significant rain from Isaac on the Central Gulf Coast from Gulf Shores over to Destin, based on everything we see now. However, the surf should be pretty rough and red flags will most likely be flying early in the week; the surf will calm down over the latter half of the week as Isaac moves away.
*Rain is possible from Isaac from Panama City east, but again this is a bit “iffy” and will all depend on the track of Isaac. Gut feeling says the most widespread rain shield will be from Apalachicola east.
*As Isaac moves northeast, soaking tropical rain is likely over the Carolinas and the middle Atlantic coast region by the middle of next week.
Remember, with most tropical systems there is a surprise or two along the way, so keep an eye on the forecast here for changes.
BEACH WEATHER: The weather actually looks great on the Central Gulf Coast through Saturday, with about 7 to 9 hours of sunshine each day from Gulf Shores to Panama City and only widely scattered showers. The weather from Sunday on will depend on the track of Isaac as discussed above.
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.
CONNECT: You can find me on all of the major social networks…
Look for the next Weather Xtreme video here by 3:30 or so this afternoon… enjoy the day!
