Irene Shows Eyewall, Will Strengthen Near the Bahamas
Irene Visible Satellite, Image: NOAA
Irene Infrared Satellite, Image: NOAA
Visible satellite imagery showed a better defined eye and eyewall for Hurricane Irene this afternoon. Since then, the eye has become obscured. Irene is bearing down on the Turks and Caicos with 90 mile per hour winds. In the last 24-hours, Irene’s interaction with the island of Hispaniola has had an impact on the developing storm, maximum sustained winds were at 100 miles per hour for the last 18 hours. There was also a small amount of wind shear over the island. It’s possible that wind shear has played a part in the storm not undergoing a rapid intensification.
National Hurricane Center is reporting in its latest discussion that wind shear may limit rapid intensification for the next 24-hours. Wind shear is expected to relax near the Bahamas.
The track continues to shift east. Now, the Outer Banks of North Carolina and metro areas of New Jersey and New York need to prepare for a possible landfall.
Irene 5 Day Forecast Cone, Image: NOAA
However, if you look at the latest computer tracks from Hurricane Irene, I’m starting to wonder if this storm is going to be steered away from the East Coast of the United States by a deepening trough along the East Coast.
Computer Models, Image: Colorado State University
The official track from the National Hurricane Center continues to be the outlier or the track on the edge of the computer model forecasts. Usually the National Hurricane Center track line follows the consensus of the forecast guidance from the models. The model consensus now takes the storm toward Massachusetts and New England. The storm would weaken if it moves into the far northern Atlantic because of the cooler water and interaction with the strong winds of the mid-level trough.
Dawn Brown, FOX 8 New Orleans
Wind Shear is Ripping Ida Apart
Ida Weakens, Image: NOAA click to enlarge
Ida is looking pretty ragged this morning as wind shear over the Gulf Coast is starting to tear the storm apart.
Hurricane Ida’s winds are down to 80 miles an hour. 30 knots or 35 mile per hour wind shear is tearing the storm apart. National Hurricane Center forecasters still forecast a hurricane at landfall, but I think that’s generous to say the storm will maintain these winds over the next 24 hours. I think heavy rain and possibly up to 60 mile per hour winds at landfall are what Gulf Coast residents can expect out of this storm. The tropical storm force winds will be relegated to the Alabama/Florida border.
Hurricane watches and warnings remain for the northern Gulf Coast. For the latest watches and warnings, go to GET YOUR LOCAL TV FORECAST! on the right hand side of this page. It is the last green tab on the right. You can watch forecasters from New Orleans, Louisiana to Tampa, Florida forecasting this storm!
Ida Track, Image: NOAA click to enlarge
-Dawn Brown
Ida Strengthens… Cat 1 Hurricane Again
Hurricane Ida, Infrared Satellite, Image: NOAA click to enlarge
Update from the The National Hurricane Center:
1115 PM EST SAT NOV 7 2009 …IDA REACHES HURRICANE INTENSITY… DATA FROM NOAA BUOY 42056…LOCATED IN THE NORTHWESTERN CARIBBEAN SEA ABOUT 120 MILES…195 KM…EAST-SOUTHEAST OF COZUMEL MEXICO… RECENTLY REPORTED A 1-MINUTE SUSTAINED WIND OF 74 MPH…119 KM/HR. THIS INDICATES THAT IDA HAS ONCE AGAIN REACHED HURRICANE STATUS… WITH MAXIMUM SUSTAINED WINDS OF AROUND 75 MPH…120 KM/HR. AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT IS CURRENTLY APPROACHING IDA AND WILL PROVIDE ADDITIONAL INFORMATION ON THE INTENSITY AND STRUCTURE OF THE HURRICANE IN THE NEXT FEW HOURS.
Ida Track Forecast, Image: NOAA click to enlarge
The track forecast has not changed much over the last 24 hours, with the exception that Ida may retain tropical characteristics until it is near landfall in the panhandle of Florida. Portions of the northern Gulf Coast continue to be under coastal flood watches. Heavy rain will also be a problem as a cold front slams into the approaching tropical air mass. Why does the National Hurricane Center think Ida will weaken in the center of the Gulf of Mexico?
Wind Shear Analysis, Image: University of Wisconsin click to enlarge
Once again, we need to revisit wind shear. Taking a look at this current wind shear analysis from the University of Wisconsin, the yellow lines in the Gulf of Mexico show us how much wind shear the storm will run into once Ida cross the Yucatan Straits. This map is difficult to read. What you need to know is the current wind shear over the Gulf exceeds 30 knots or about 35 miles per hour. This can be a hostile environment for tropical systems. National Hurricane Center forecasters expect Ida to remain a hurricane for the next two days, let’s see if that occurs.
-Dawn Brown
Tropical Storm Ida Will Bring Heavy Rain
Tropical Storm Ida 5-day Track, Image: NHC, NOAA
Tropical Storm Ida has made a comeback, packing 60 mile per hour winds this Saturday morning as it quickly makes a beeline for the central Gulf of Mexico. The northern Gulf Coast could be slammed with heavy rain Monday and Tuesday. You’ll notice on the hurricane tracking map from the National Hurricane Center Ida will become extra-tropical or more like a winter-type cyclone by Tuesday. Strong winds and large waves could still affect portions of the Gulf Coast, and you need to watch your local TV forecast for the latest watches and warnings — go to GET YOUR LOCAL TV FORECAST! in the right hand column of this website. You can see from the tracking map that even though portions of Southern Louisiana, Mississippi, Alabama and the panhandle of Florida will receive some heavy rain and gusty winds, they will avoid the damaging winds and coastal surge associated with a tropical storm or hurricane.
Tropical Storm Ida Visible Satellite, Image: NOAA
The storm is looking fairly healthy this morning. This wasn’t unexpected as it is over a deep well of warm water over the northwestern Caribbean Sea. It is possible it could strengthen into a hurricane in the next 24-hours as it makes its way through the Yucatan Straits. Once Ida moves into the Gulf of Mexico, it will encounter cooler waters and high wind shear. (60-90 miles an hour) For more information on wind shear and how it affects storms, see my previous blog from earlier this week.
-Dawn Brown
Ida Still Weak, Heads Toward Gulf
Ida Heads Toward Gulf: Image, NOAA (click to enlarge)
This is a current satellite image of Tropical Depression Ida, which is still spinning on the coastal plains of the Nicaraguan/Honduran border (It is still inland-will move over the western Caribbean Sea later today.) For the last 24-hours, computer models continue to develop Ida back into a tropical storm or minimal hurricane and send it into the Gulf of Mexico.
That is where the forecast gets a little tricky. At this time of year, strong winds over the southern portion of the United States could either send Ida on a fast track toward Florida (possibly as a minimal hurricane), or tear the storm apart in the middle of the Gulf. Wind shear in the middle of the Gulf of Mexico right now is about 45-90 miles per hour. Tropical systems don’t like wind shear greater than about 20 miles per hour.
The National Hurricane Center is going with more typical thinking for the weather patterns at this time of year. Forecasters there believe the storm will transition from a tropical storm into a winter-type low pressure system somewhere in the middle of the Gulf of Mexico, and head toward Florida (possibly) as a heavy rainmaker.
Computer Model - Ida Tuesday, Image: Unisys Weather
This computer model image shows the storm pattern across the United States. (The color contours show areas of stronger winds and colder air–the blues and greens.) What is important for you to note about this image is where Ida is located on this model on Tuesday. It is just north of Cuba. Now, let’s take a look at the computer model image from Wednesday.
Computer Model - Ida Wednesday, Image: Unisys Weather
In this image, Ida has weakened, and the steering currents aren’t letting it move closer to the northern Gulf of Mexico. In fact, the steering currents aren’t letting the storm move much at all. That’s why I say the forecast gets a little tricky when the storm tries to get into the Gulf of Mexico, and why forecasters say things like Ida will be “stranded” once it gets into the Gulf. It’s because the upper level steering currents won’t let it move closer to the United States. This is why the spaghetti plot lines go straight north for the next 5 days, and then they bend BACK toward the South.
Ida Spaghetti Plots, Image: Weather Underground
These spaghetti plots from Weather Underground tell the story. For the latest track forecast on Ida, please go to my Hurricane Tracking links to your left.
Dr. Jeff Masters has some thoughts in his blog today on why Ida will strengthen in the western Caribbean Sea, despite some pretty good wind shear, because of the large amount of warm water. Also, I’d be interested to see what Max Mayfield, (former director of the National Hurricane Center), has to say about Ida in his blog later today, since he’s still based out of Miami. Check out their hurricane blogs to your left.
Meanwhile, have you checked out the heavy rain forecast for the northern Gulf Coast on Monday. Tropical moisture will be heading toward the northern Gulf ahead of Ida for Sunday through Tuesday.
-Dawn Brown
Tropical Storm Ida
- Wind Shear, Image: University of Wisconsin
Tropical Storm Ida is spinning off the coast of Nicaragua… and is expected to dump a lot of heavy rain in Central America. I’m a little embarrassed about the graphic I’m posting to my website, mainly because it’s very difficult to read. It’s important to show folks living in the United States, because it gives you an idea of the kind of environment a storm like Ida faces at this time of year if it moves close to the United States. Ida is the blob of white circled in red on the map. The white outlines to the left show Central America. The yellow lines on the map tell us the kind of wind shear occurring near Ida right now.
A New Invest In the Atlantic
Invest 98L (courtesy NOAA) Click to Enlarge
The National Hurricane Center’s hurricane models are trying to develop a tropical wave out in the Atlantic off the coast of Africa. It is currently called 98L. (You can always click on the image to make it larger.) I think it’s a good chance this system could develop into another tropical system based on warm sea surface temperatures and favorable wind shear where it’s currently located. However, as it continues its westward migration, it will run into a good bit of wind shear,
Wind Shear (Courtesy NOAA - Hurricane Research Division)
and that will cause problems for the developing storm. As I’ve mentioned in the past, global computer models have a tough time forecasting the strengthening of a storm, the track forecast is more reliable. And the track forecast has this system turning north in the middle of the Atlantic, if it does develop. With the current weather pattern, upper level troughs spinning off the East Coast of the United States, these storms are being turned north before they can come close to the United States this year. Tomorrow, I’ll explain what an upper level trough is… and why it’s helped us out this year!
These troughs have also created a cool summer for a good section of the country.
Dr. Jeff Masters from Weather Underground, looked at the climate data from this past summer, and had some interesting information about our summer.
Here’s the script from his blog:
“A cool August and cool summer for the U.S.
For the contiguous U.S., the average August temperature was 0.6°F below average, making it the 30th coolest August in the 115-year record, according to the National Climatic Data Center. The U.S. as a whole was below normal for the summer period (June – August). A recurring upper level trough held the June – August temperatures down in the central states, where Michigan experienced its fifth coolest summer, Wisconsin, Minnesota, and South Dakota their seventh coolest each, Nebraska its eighth, and Iowa its ninth. In contrast, the temperatures in Florida averaged out to be fourth warmest, while Washington and Texas experienced their eighth and ninth warmest summers, respectively.
U.S. precipitation in August was below average, as the month ranked 28th driest in the 115-year record. Arizona had its fourth driest August, New Mexico its fifth, and it was the eighth driest August for Colorado, Utah and Texas. Arizona observed its third driest summer, while both South Carolina and Georgia had their sixth driest. It was the 8th wettest summer on record in the Northeast.
At the end of August, 13% of the contiguous United States was in moderate-to-exceptional drought. This is a drop from the 19% figure observed at the beginning of the year. These extreme drought regions were exclusively in South to Central Texas. However, significant drought relief occurred in this region the second week of September, when a large area of tropical moisture settled in over the region, bringing heavy rains. About 19 percent of the contiguous U.S. fell in the severely to extremely wet categories in August.”
The link for Dr. Jeff Masters Wunderground Blog is on the left side of my screen. I’m sure he’ll have something about Invest 98L later today.
I’ll talk to you tomorrow! -Dawn Brown