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

Irene Misses Hispaniola, Now a Category 2

Infrared Satellite, Image: NOAA

Hurricane Irene blew up into a category 2 hurricane with 100 mile per hour winds north of Hispaniola tonight. It missed the island is now poised to develop into a major (category 3 or stronger) hurricane as it makes its way toward the Bahamas.

At least one computer model previously forecast Irene missing Hispaniola and developing into a major hurricane. That computer model has Irene on track toward the border of South Carolina and North Carolina  between Charleston and Wilmington. Most of the computer models have developed the storm into a major hurricane off the East Coast of the United States. For at least three more days, it’s going to be in a favorable environment for intensification. There is the possibility that due to the trough developing off the eastern United States, it may weaken slightly before landfall.

Computer Models, Image: Colorado State University

This same trough is expected to draw Irene north toward the Carolinas. Computer models and the National Hurricane Center continue to shift east. If you look at the latest models, there is even a possibility that Irene could miss both North and South Carolina. This scenario is not forecast at this time by the National Hurricane Center.

The National Hurricane is urging residents along coastal United States to be aware the the forecast error for the 5-day forecast is from 200 to 250 miles. (The forecast error is how they develop the “cone of error or uncertainty) that you see in the graphic below.

Irene 5 Day Forecast, Image: NOAA

Dawn Brown, FOX 8 New Orleans

Hurricane Irene May Strengthen to Major Hurricane

Infrared Satellite, Image: NOAA

Hurricane Irene is forecast to strengthen to a category 3 hurricane packing 115 mile per hour winds before making landfall in South Carolina. That is the latest forecast from the National Hurricane Center. The landfall in South Carolina is five days from now. There may be some adjustments to that forecast track, as the hurricane center continues to edge the track farther east.

The eastward movement is now sparing Florida and a major portion of the Dominican Republic.

5 Day Forecast, Hurricane Irene, Image: NOAA

For the latest tracking information and analysis, go to MYL’s Hurricane Tracking page.

Dawn Brown, FOX 8 New Orleans

Arlene to Drench Drought Stricken Mexico

The Latin American Herald Tribune is reporting today that Mexico is experiencing its worst drought in 70 years.

Tropical Storm Arlene may alleviate some of the drought, although many mountainous regions may experience flash floods because of the amount of rainfall associated with the tropical storm.

Tropical Storm Arlene, Image: NOAA

The satellite presentation became much more impressive in the overnight hours, most likely due to the lack of wind shear in the southwestern Gulf of Mexico. Thunderstorms started sprouting up in the southern and eastern section of the storm early this morning. It’s possible Arlene could reach just below hurricane strength before making landfall between Tampico and Poza Rico. The topography in this section of Mexico makes it susceptible to flooding rains.

Although Arlene doesn’t have much time to strengthen, it could be just below hurricane strength before making landfall between Tampico and Poza Rica. For complete tropical storm coverage, visit TV stations in coastal towns of Texas like Houston and Corpus Christi.

Dawn Brown, FOX 8 New Orleans

Alex and the Oil Spill

Tropical Storm Alex forms off the coast of the Yucatan Peninsula in the warm waters of the Caribbean Sea.

Infrared Satellite, TS Alex, Image: NOAA

The current track takes Alex toward the Yucatan, weakening as it crosses the peninsula. Hurricane forecasters expect it to strengthen once again in the southwestern Gulf of Mexico, moving toward the south Texas coastline before possibly curving toward the west-southwest.

Official Forecast Track, Tropical Storm Alex

Most of the computer models agree on this forecast track. Hurricane specialists from the National Hurricane Center presented their post-season analysis of the 2009 Atlantic Hurricane Season at a meteorological conference in Miami this week. During their presentation, they announced the European Model, or the ECMWF, has delivered the most successful track forecast the past few years. That model takes Alex toward the southwestern Gulf of Mexico toward central Mexico. The ECMWF isn’t plotted on most computer model tracking maps, if you follow those.

You can find the link to the European model in my link to tracking hurricanes, but it’s hard to read for most people. Keep in mind that the hurricane specialists know which models are giving the best performance when they issue their track forecast, so you can be confident that when you are looking at the 5-day forecast from the National Hurricane Center, that is the most accurate information available.

This past week, two of the government models, the HWRF and the GFDL, were taking the disturbance in the Caribbean to the northern Gulf of Mexico. You can’t really follow computer models for tropical disturbances until there is a tropical depression, or a center of circulation. It’s hard to explain, but the mathematical models are set up to take a storm that has already formed and track it. They do a pretty good job of that. But, until a low, or depression has formed, you can’t rely on all those “spaghetti plots”, as they are familiarly called.

I walked up to Bill Read, the Director of the National Hurricane Center, and I said, “Hi, Mr. Read, I’m Dawn Brown from FOX 8 New Orleans. What’s up with the  HWRF?”

Well, he smiled and said, “We initialized the model with a fake storm…, ” to try and give people battling the oil spill an idea of where Alex might go if it formed. Basically, the hurricane specialists had to input some numbers into the storm, such as maximum winds, etc., to run the model, because once again, these models are not designed to work unless there is a storm.

This is why last week, when most of the models were taking the tropical disturbance toward the west, the HWRF and GFDL were headed straight north. Now those two models are more in line with the other computer models and the official track from the National Hurricane Center reflects that.

Does that mean workers near the oil spill need not worry? No. We still have to watch Alex cross the Yucatan and see how it fares in the southwestern Gulf in the beginning of next week.

By the way, I really like Bill Read. Straight shooter, very smart, great communicator.

-Dawn Brown

My New Gig at FOX 8. Check Out The Weather Lab!

It was a gorgeous day in New Orleans today. Dry, breezy and sunny. It’s the kind of weather we look forward to all year. It’s been a cold winter down here, we’ve been waiting for Spring.

Cirrus Clouds, New Orleans Sunset

On my way to talk to a community group tonight, I shot this photo as I was looking to the southwest. What a gorgeous sunset. Louisiana often has beautiful sunsets and sunrises. Interesting cloud formations reflect the sunlight as the sun rises and falls.

Meanwhile, I’ve been neglected my weather blog. My new job at FOX 8 is creating new and interesting challenges. I love my job. We launched a new show called FOX 8 Morning Call on February 1.

Here’s a picture of Chris Franklin and me from this morning at 5am.

Chris Franklin and Dawn Brown, WVUE New Orleans

We started this new show that’s kind of like the Weather Channel, but it’s focused on Southeast Louisiana. We do the usual temperatures, rain chances, forecast, but then we get to spend extra time talking about the wave heights and sea surface temperatures in the lakes and Gulf of Mexico, the kind of stuff fisherman and mariners are interested in. We have the buoy data from all the Gulf  Coast buoys plotted in our new weather system.

Here’s the pic I took Friday of the current sea surface temperatures on one of our new weather systems.

Sea Surface Temperatures, (3/12/2010)

Here’s Chris at the weather wall. Because I’m usually doing the weather, I never get to see how weird it looks that we’re pointing at a blank green wall.

Chris Franklin, WVUE New Orleans

Our weather graphics are projected onto the wall, and we are “keyed” out of the graphics. We can’t wear green or we would blend right into the graphics. We’ll probably both get pinched on St. Patty’s Day!

It’s awesome having two meteorologists in the mornings. Besides having the extra help with forecasts and graphics, we get to explain basic weather phenomenon, like hail, high pressure systems, sea fog, etc.

Every week, Chris and I also host a segment called “Weather Lab”, where we explain basic weather terms with experiments. Last week, Chris crushed a soda can with air pressure.

I’m having a blast! However, I’ve been remiss with my weather blog and adding new features to my website. I’m getting back on track… bear with me.

Thanks – Dawn Brown