At the beginning of last week, when it became apparent that the northeast would be bracing for a rare hurricane, I started researching hurricanes that have hit New York City. At the same time, I started linking my website to other TV stations in the line of fire: Wilmington, Norfolk, New York City. I happened to watch Lee Goldberg of WABC in New York. He’s a favorite of my mother-in-law’s–and her son, my husband, is a meteorologist.

Goldberg was taking a look back at the hurricanes that have affected New York City and the northeast. There are a couple noteworthy ones; the 1821 Norfolk/Long Island Hurricane, the 1893 NYC Hurricane, the 1938 Long Island Express and the 1944 Great Atlantic Hurricane. Then, there are a couple of noteworthy storms of recent memory: Hurricane Donna, Hurricane Gloria and Hurricane Floyd. (For hurricane research, you can also go to the National Hurricane Center website, but storm information only goes back to 1958.)

Goldberg decided the storm that came closest to Irene was Floyd. I applaud him for his bravery. Other national outlets were forecasting Lower Manhattan, Queens and other areas would be under water. He was forecasting major power outages and flooding rains from torrential downpours. He forecast that some low-lying areas would take on water. I can’t quote him on every thing he said, his forecast was very area specific because he knows the area. I don’t. I live in New Orleans. I can look at maps, try and find elevations levels, figure out which areas face the water, figure out all the inlets and outlets, which areas are prone to flooding, which areas are better protected. I can look at the bathymetry of the coastline and try and figure out why certain areas will flood and some won’t. I’ve done it for hurricanes here.

But honestly, that kind of research can take years. When you are forecasting for a local TV market, you take the time to look up all that information, so you can give an accurate and meaningful forecast. You live in the area you are forecasting, amongst the people you are forecasting to. When you broadcast for a national outlet, you’re just trying to get viewers.

I rarely comment in this blog. But watching the misinformation provided by national media outlets made me turn the cable TV off this week, and rely on my online TV forecasters. The ones from the local markets, the ones who actually care what speed the winds are, how much rain they get, how high the storm surge will actually be. They try and give an accurate forecast because they are personally relying on it.

Irene Infrared Imagery, Image: NOAA

To track Irene, go to MWL’s hurricane tracking page. Latest track available from National Hurricane Center. You can check out expert weather bloggers on the links to your left. I’ll have more analysis of Hurricane Irene later in this post.

I’ve been researching land falling hurricanes close to the track of Irene and it appears Hurricane Floyd (1999) may be the storm with the closest track and intensity to estimate the damage residents along the Mid-Atlantic and East Coast can expect.

Hurricane Floyd 1999 Track

Hurricane Floyd 1999, Image: NOAA

Floyd made it’s first US landfall in Cape Fear, North Carolina on September 16th as a Category 2 hurricane with 105 mile per hour winds. (Hurricane Irene currently has maximum sustained winds of 100 miles per hour. It is 265 miles south-southwest of Cape Hatteras, North Carolina.)

With maximum sustained wind of 105 miles per hour, storm surge along the southeastern portion of the state was 9 – 10 feet. This caused significant destruction along coastal communities. Most of the damage from Hurricane Floyd occurred as a result of inland flooding. Rainfall totals from 15-20″ of rain fell across portions of the state. River levels were high as a result of Hurricane Dennis passing through North Carolina weeks earlier, dumping 15″ of rain. (Coincidentally, another Hurricane Irene passed by North Carolina weeks after Floyd, dumping even more rain on the state.)

Hurricane Floyd Track and Rainfall Accumulations, Image: NOAA

Floyd continued to move north toward Virginia, crossing the Delmarva Peninsula, briefly entering the Atlantic Ocean once again before making another landfall as a tropical storm in Long Island, New York. Torrential rainfall was reported in Virginia, Maryland, Delaware, Pennsylvania, New Jersey, New York and other portions of the Northeast and New England. Floyd produced a storm surge of 2.8 feet in Philadelphia. The greatest threat from Floyd was widespread power outages ( close to 1.3 million people in three states) due to strong winds and heavy rains. Mudslides occurred along bluffs overlooking the Hudson River due to heavy rains.

Irene tracked due north for the past 12-hours, but as of the latest advisory has made turns to the north-northeast.

Dry air is being pulled into the storm from the south and southwest weakening the storm slightly as it makes its way toward the Carolina coast. It is still a powerful storm.

Irene Rainfall Forecast, Image: NOAA

Damage impacts include 10 – 15″ of rainfall.  Storm surge along the North Carolina coastline could be anywhere from 6 – 11′, similar to Hurricane Floyd. The National Hurricane Center is also warning:

"STORM SURGE WILL RAISE WATER LEVELS BY AS MUCH
AS 4 TO 8 FEET ABOVE GROUND LEVEL WITHIN THE
HURRICANE WARNING AREA FROM THE NORTH CAROLINA/VIRGINIA
BORDER NORTHWARD TO CAPE COD
INCLUDING SOUTHERN PORTIONS OF THE CHESAPEAKE BAY AND ITS
TRIBUTARIES. NEAR THE COAST...THE SURGE WILL BE ACCOMPANIED BY
LARGE...DESTRUCTIVE...AND LIFE-THREATENING WAVES."

Storm surge is dependent on many factors; including the shape of the coastline, the terrain of the earth underwater, the shape of the inland waterways. Storm surge can wash over barrier islands if its higher than the elevation. Persistent winds can drive water up tidal bays and rivers such as Chesapeake Bay and and the Delaware River and cause inland flooding due to rising river levels.

Here are links for coastal flood impacts for the following locations: Virginia, Delmarva Peninsula, New York City and Long Island.

Other storms of note for the New York area with a similar path include the 1821 Long Island/Norfolk Hurricane, the 1893 New York Hurricane, and the 1944 Great Atlantic Hurricane. However, when I looked back at the history and strength of the storms on their path toward North Carolina, the storm that best estimates the possible impacts from Irene is Hurricane Floyd.

My previous post has links to local TV forecasters in the impacted regions.

Dawn Brown, FOX 8 New Orleans.

Irene Visible Satellite, Image: NOAA

To track Hurricane Irene, head to MYL’s Hurricane Tracking page or the National Hurricane Center website.

On Saturday, when the NHC issued its first advisory on what was then Tropical Storm Irene, the Turks and Caicos Islands were not within the National Hurricane Center track forecast. Five days later, the island chain was squarely in the most dangerous section of a major hurricane.

National Hurricane Center forecasters are emphasizing the error and uncertainty in their discussion today. Currently, the NHC is uncertain whether Irene will affect the most populous area of the United States once it starts its trek northward, turned by steering currents over the United States and the Atlantic Ocean basin. The current track has landfall on the far outer edge of the Outer Banks and then a second landfall in Montauk, New York, the most eastern point of Long Island, before moving through coastal Connecticut, Rhode Island, Massachusetts, coastal New Hampshire and then Maine. The track has been nudged farther east but hurricane forecasters aren’t confident in that forecast.

This storm is gaining strength over the warm waters of the Bahamas and the East Coast of the United States will have to continue to monitor Irene.

Dawn Brown, FOX 8 New Orleans

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

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

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

National Hurricane Center Track, Image: NOAA

Computer Model Tracks, Image: Colorado State Track Model Guidance

Dawn Brown, FOX 8 New Orleans

Tropical Storm Harvey, the 8th storm of the 2011 Hurricane Season, is moving through central Belize tonight. It will likely degenerate over Guatemala and Mexico, but is producing quite a bit of rainfall in and around the center of circulation.

Infrared Satellite, TS Harvey, Image: NOAA

Harvey formed in the central Caribbean and didn’t pose a threat to the United States from its inception. At the same time Harvey or TD 8 was forming, a very unimpressive tropical wave was catching our attention in New Orleans, merely based on the long-range computer models.

The models, mostly notably the GFS, or Global Forecast System, was projecting a major hurricane to form as it approached the Caribbean and making landfall somewhere along the US coastline in the end of August.

In 2006, the GFS predicted a similar occurrence about 10-15 days out.

2006 Hurricane Ernesto, Image: Unisys

It turned into Hurricane Ernesto, a category 1 hurricane, that weakened substantially over western Haiti and eastern Cuba, before hitting Florida as a tropical storm. The only reason I bring up Hurricane Ernesto is to touch on the current unreliability of long range computer models. And really what I mean by long-range, is past 3 or 4 days. As I state this, the global computer models have improved. Last year, I noticed that the GFS was doing a fairly good job of forecasting the inception of a storm, meaning in 10-15 days, the global computer models could pick up on a closed circulation (or a tropical depression) forming. I emailed an expert the National Hurricane Center about it, and they concurred, that they had made some improvements to the GFS. What the GFS could not do and still has trouble telling us, is how strong this system will be when it arrives. However, there is another global computer model that is being heavily relied on by hurricane forecasters that is doing a fairly good job in telling us which storms will strengthen and where they will go.

National Hurricane Center

Last year, while attending the annual Broadcaster’s Conference of the American Meteorological Society in Miami, attendees were privileged to meet, not only the entire staff of hurricane forecasters from the National Hurricane Center, but we also got every insight they could offer to how they put together the forecast. One of the forecasters/researchers also told us the ECMWF, the forecast put other by the European Centre for Medium Range Weather Forecasts had been beating their track forecast for the past couple of years. The percentage was small, but somehow, their global forecasting model was able to beat forecasters with 20-30 years of experience. This may get some guffaws from readers, but keep in mind that the official track by the National Hurricane Center was statistically better than all of the other computer models out there. That means—don’t tie yourself to one model.

Ever since they told me that, I can’t help it.  I rely on the “European”.

But then, last year, I noticed the GFDL, the United States’ global hurricane model, nailing the forecast track as well. I was hopeful, proud. I’m not sure why, but I guess it bothered me a little bit that Europe, which is barely affected by hurricanes, could forecast them better than us! Then the GFDL started really performing well on the track and intensity.

That was last year. This year, I’m back to the European. I don’t know what happened to the GFS and GFDL, but this hurricane season, it’s been having some wild swings when it comes to storm tracks. It also ratchets some storms into a major hurricanes 10-15 days out like it did back in 2006.  The European only goes out 8 days, but in the last few years, I felt confident telling my viewers which way the storm was headed and relatively how strong the storm was going to be when it got there. This year, it’s been guiding me through Arlene, Bret, Cindy, Don and Emily. It forecast Emily forming briefly, dying somewhere north of Hispaniola and then possibly reforming as a weak system before getting carried northeast with a trough of low pressure off the East Coast. Guess what happened? Exactly that. Now, the GFS did eventually forecast a similar scenario. And, it’s much easier to be confident with a forecast when more of the computer models are in alignment.

And the European only guides me in track and possible strength. It doesn’t give particulars, what’s causing the weakening/strengthening, how weak/strong will the storm be, what areas could suffer torrential downpours or high winds. It’s merely guidance. We still have to do all of our own analysis of the wind shear, upper air pattern, the water vapor (these tropical systems really struggle with dry air), the Saharan Air Layer, everything that tells us what kind of storm we’ll be dealing with. But, it gives me confidence to let me know if I need to be gearing up for a 5-day stretch of spending the night in the weather center. (Technically I got to go home during Gustav—I lived 3 blocks from the station!)

Infrared Satellite, Invest 97L, Image: NOAA

In terms of Invest 97L, it’s been undergoing some interaction with dry air and wind shear that has kept it from developing into Tropical Depression # 9 or Tropical Storm Irene. It looks like it’s going to be a tropical storm in the next 24-hours. It also looks like despite dry air still to its north and west and its possible interaction with Hispaniola and Cuba, it will most likely hit Florida as a tropical storm or possibly even category 1 hurricane.

It looks like the persistent trough off the East Coast will keep it from affecting the northern Gulf Coast states.

I say this in confidence at this point because of my faith in the European. Also-because the other computer models are lining up with a similar forecast.

But… since I live along the Gulf Coast and not along the beaches of the Mediterranean, I still keep my hurricane plan in place until October 15th.

Dawn Brown, FOX 8 New Orleans

P.S. This is my anecdotal account of forecasting with models, Wunderblogger Jeff Masters has a much more studious approach to explaining the performance of models in his blog, click here.

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

Tropical Storm Arlene, Image: NOAA

The National Hurricane Center began issuing advisories on Tropical Storm Arlene at 7pm Central Daylight Time this Tuesday, June 28th. The storm’s satellite presentation isn’t all that impressive, but it’s kicking up some good wave heights in the central Gulf of Mexico (up to 12′). The area of showers and thunderstorms west of the Yucatan Peninsula has been fairly persistent over the last few days and observations near the center of the storms show maximum sustained winds of about 40 miles per hour.

Arlene is expected to make landfall just south of Tampico, Mexico sometime on Thursday. It could provide some heavy rainfall for Tampico, Ciudad Valle and San Luis de La Paz Mexico. This is a mountainous region of central Mexico and tropical storms can dump copious amounts of rain over this region.

For the latest statistics on Arlene, go to the National Hurricane Center website. This is expected to be a fairly active hurricane season.

Dawn Brown, FOX 8 New Orleans