The Threat Invest 95L Poses to the Gulf Coast
Invest 95L Satellite Imagery, Image: NOAA
National Weather Service link tracking Gulf Low. (Click on the Gulf Low tab above the radar imagery.)
Meteorologists across the Gulf Coast are closely watching Invest 95L despite its lack of organization and poor chance of development. With oil still gushing from the bottom of the Gulf of Mexico, this low and its associated wind and wave action could drive more oil into sensitive marshes and estuaries along the northern Gulf Coast. Yesterday, hurricane specialists Lixion Avila and Chris Landsea identified the low and gave it a 10% chance of development. We’d already had our eye on it in the FOX 8 Weather Department. Today, Avila and Landsea give it a 20% chance.
Stalled Frontal Boundary, Image: Unisys
In early June and July, the main source of tropical development in the Gulf of Mexico is a low that forms off of a stalled frontal boundary in the gulf. You can see the position of the low is about 150 miles or so south-southeast of the boot of Louisiana. There’s a lot of wind shear and dry air affecting the low right now keeping it from developing into anything tropical. Wind shear is expected to remain fairly strong over the next couple of days. So, for this thing to develop, wind shear has to relax and the dry air will have to be replaced by a warm and tropical air mass.
Water Vapor Imagery, Image: NOAA
More troubling for Gulf Coast residents is the wind and wave action associated with a low pressure system east of Louisiana. With oil gushing offshore, a persistent southeast wind could drive the oil onshore. Wave heights are currently about 5 feet around the location of the Deepwater Horizon Incident. Wave heights are forecast to become 6′ offshore, keeping skimmers and other cleanup craft in safe harbor.
-Dawn Brown
Field Trip to the National Hurricane Center
Senior Hurricane Specialist Dr. Lixion Avila Studies Tropical Storm Alex
Field trip day! About 100 or so television meteorologists, including Bob Breck, my fiance Jonathan Myers and I, boarded a bus to the National Hurricane Center in Miami yesterday.
Bob Breck and Dawn Brown, FOX 8 New Orleans, National Hurricane Center
It was exciting for two reasons. One, I’ve never been there. And, two, there was a tropical storm in the Caribbean Sea. Alex doesn’t look like it will be much of a threat to New Orleans when it reemerges in the Bay of Campeche in the southwestern Gulf of Mexico. But, we don’t take anything for granted until a tropical system has dissipated. This was going to give me a chance to discuss the storm with the experts at the hurricane center.
When you enter the NHC, there’s a big media room to brief reporters during hurricane season. They now have the hurricane specialists separated from the media by glass walls. I can’t imagine it before they put in the glass. The hurricane specialists are trying to study all this satellite and storm data, and they have these cameras over their shoulder, studying them! Now, only one or two cameras are allowed in the media room during a land-falling hurricane.
National Hurricane Center
Behind the glass walls, hurricane specialists track tropical disturbances in both the East Pacific and Atlantic Ocean basins. Today there were 3 tropical cyclones. Hurricane Darby and Celia in the East Pacific and Tropical Storm Alex in the Atlantic.
Senior Hurricane Specialist Dr. Lixion Avila was the meteorologist tracking Alex. A Cuban native, he was issuing watches and warnings for Mexico, Belize and Honduras, the countries affected by the storm on Saturday.
There were 3 other meteorologists forecasting marine advisories for shipping in the Atlantic and Pacific Ocean basins. What an enormous area to cover. The hurricane center also has storm surge specialists, researchers, etc. All in all, they don’t have a huge staff. The hurricane specialists appear to be a tight knit group. It makes sense since they have to work closely together over a period of days while they are watching a storm.
I’ll add a little bit more about my visit to the Hurricane Research Division when I update this tomorrow.
Here’s the latest track forecast for Alex. -Dawn Brown
Alex 5-Day Forecast, Image: NOAA
Less Confusing Saffir-Simpson Scale Released
Hurricane Ike, Image: NOAA
When Hurricane Ike slammed into the Texas coastline in September 2008, hurricane forecasters rated it a category 2 hurricane on the Saffir-Simpson scale with maximum sustained winds of 110 miles per hour. The storm surge associated with Ike topped 15-20 feet. If you used the Saffir-Simpson scale as a guide, the storm surge associated with Ike should have been about 6′. (See the graphic below.) The mismatch between the wind speeds generated by the storm and the associated storm surge have led the National Hurricane Center to drop storm surge from the widely used scale.
Old Saffir-Simpson Scale, Image: NOAA
The Saffir-Simpson scale was developed in 1971 by engineer Herbert Saffir and National Hurricane Center Director Bob Simpson to help forecasters explain the potential damage from a hurricane to the public. It was mainly designed as a way to explain what damage would occur to structures if a hurricane hit with 75 mile per hour winds, 95 mile per hour winds, 110 mile per hour winds, etc. After the scale was developed, forecasters realized storm surge was a significant part of the damage from a hurricane, and they tried to come up with the height of the storm surge associated with different wind speeds. Unfortunately, it has led to errors in forecasting and misleading the public. The effect of storm surge on a coastline depends on the strength of the winds, the direction of the storm, the topography of the coastline, and the bathymetry (or topography of the coastline under the water.) Now, individual weather service offices, as well as universities, produce individual storm surge forecasts for each storm depending on the strength of the storm and its track. Here are the guidelines given today by the National Hurricane Center for the now called Saffir-Simpson Hurricane Wind Scale:
| Category | Winds | Effects |
|---|---|---|
| One | 74-95 mph | No real damage to building structures. Damage primarly to unanchored mobile homes, shrubbery, and trees. Also, some coastal road flooding and minor pier damage |
| Two | 96-110 mph | Some roofing material, door, and window damage to buildings. Considerable damage to vegetation, mobile homes, and piers. Coastal and low-lying escape routes flood 2-4 hours before arrival of center. Small craft in unprotected anchorages break moorings. |
| Three | 111-130 mph | Some structural damage to small residences and utility buildings with a minor amount of curtainwall failures. Mobile homes are destroyed. Flooding near the coast destroys smaller structures with larger structures damaged by floating debris. Terrain continuously lower than 5 feet ASL may be flooded inland 8 miles or more. |
| Four | 131-155 mph | More extensive curtainwall failures with some complete roof strucutre failure on small residences. Major erosion of beach. Major damage to lower floors of structures near the shore. Terrain continuously lower than 10 feet ASL may be flooded requiring massive evacuation of residential areas inland as far as 6 miles. |
| Five | greater than 155 mph | Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away. Major damage to lower floors of all structures located less than 15 feet ASL and within 500 yards of the shoreline. Massive evacuation of residential areas on low ground within 5 to 10 miles of the shoreline may be required. |
Better Hurricane Forecasting-More Time to Get Out
When a hurricane approaches, all the public wants to know is: Where is it going? And, do I need to evacuate?
The National Hurricane Center says better track forecasts will allow them to give you more warning if a hurricane is headed toward your city. Instead of just 24-hours notice, hurricane forecasters say the track forecasts have improved so much, they can now issued a hurricane warning 36-hours in advance of a storm. That gives residents 12 more hours to board up their house, and make preparations for the advance of the storm, including evacuating if need be. Hurricane watches will be posted along coastlines 48-hours in advance of the storm’s landfall. “With increases in population and infrastructure along vulnerable U.S. coastlines, emergency managers need more lead time in order to make life-saving decisions regarding evacuations,” said Bill Read, director of NOAA’s National Hurricane Center. (Source: NOAA)
Forecast Track: Hurricane Ida, Image: NHC, NOAA
(This is a forecast graphic. Click here for the actual track of Hurricane Ida.)
The image above is a forecast track advisory from Hurricane Ida on Sunday, November 8th when it was between Cuba and Cancun, Mexico. I’ve circled Ida’s position on the map at 12PM on that Sunday. In 24 hours, the storm was expected to still be a hurricane as it approached Southeast Louisiana, Mississippi, Alabama and the panhandle of Florida. The National Hurricane Center was giving the coastlines a 36-hour advance notice that the storm could be a hurricane or extra-tropical hurricane as it approached the coast. Now, this watch will be issued 12-hours earlier.
Will this advanced lead time in the track forecast give TV meteorologists better tools to warn the public? Yes and no. Yes, we will be able to tell the public “… We are under a hurricane watch this evening. That means National Hurricane Center forecasters believe the hurricane is going to make landfall along our coastline in the next 48 hours.”
But, we still won’t be able to tell the public with complete confidence how strong the storm will be once it approaches. We’ve said this over and over, that despite advances in forecasting the path of the storm, the intensity forecast is still far from perfect.
For example, let’s just take a look at the graphic above, when the storm was 2 days away from hitting the northern Gulf Coast.
Comparing Forecast to Actual Track, Image: NOAA
24 hours after this advisory was issued, Ida had actually weakened to a tropical storm. Thus all the hurricane watches and warnings became tropical storm watches and warnings for the northern Gulf Coast. Ida made landfall in Dauphin Island, Alabama at about 7am on November 10th as a tropical storm with 45 mile per hour winds. A substantial difference from what was forecast just 24 hours earlier.
However, the track forecast was spot on! That’s why the NHC has become more and more confident that they can tell you where the storm is headed.
And, despite the pitfalls I’ve shown you in this blog when it comes to the intensity forecast, more and more hurricane research is aiming to improve that forecast as well.
-Dawn Brown
Gulf Low Will Dump Rain, Snow
Computer Forecast, Tonight, Image: Unisys Weather
Computer Forecast, Thursday, Image: Unisys Weather
A storm system setting up over Texas and drawing moisture from the Gulf of Mexico is creating the possibility of snow over West Texas and heavy rain over Southern Texas, Louisiana, Mississippi and Alabama. (Click here for your local TV forecast.)
This same system will ride up the Appalachians Thursday, becoming a snow-maker for parts of the Great Lakes and a rain-maker for much of the Northeast.
Yesterday was November 30th, the last official day of the 2009 hurricane season. The National Oceanic and Atmospheric Administration has a full report on the less-than-average season.
-Dawn Brown
October’s Climate Report
Northeast Radar, Image: NOAA (Old)
Click for the latest Northeast Radar image.
New England is being pummeled by Ida’s rains this Friday. Marine storm warnings are in effect from Delaware and South Jersey to off the coast of Long Island to northern New England. Click on the foregoing links for the latest watches and warnings from local TV forecasters.
NOAA, the National Oceanic and Atmospheric Administration has released its climate report card for the United States. According to NOAA, the United States had the third coolest October this year and the highest precipitation totals on record.
Climate State Ranks, Image: NOAA
Precipitation State Ranks, Image: NOAA
According to NOAA, “The average October temperature of 50.8 degrees F was 4.0 degrees F below the 20th Century average. Preliminary data also reveals this was the wettest October on record with average precipitation across the contiguous United States reaching 4.15 inches, 2.04 inches above the 1901-2000 average.” (Source: NOAA)
-Dawn Brown
Remnants of Ida Flooding East Coast
National Forecast, Image: NOAA
Heavy rain continues to pound the Northeast as the remnants of Ida continue to drench Virginia, Maryland, D.C., Delaware and New Jersey. It doesn’t look like it’s going to let up until late Friday into Saturday.
Northeast Radar, Image: NOAA (Old)
Click here for the latest radar image.
Precipitation Forecast, Image: NOAA
The Hydrometeorological Prediction Center is predicting at least 5 inches of rain through Sunday for coastal areas from North Carolina to Northern New Jersey. Here’s a complete list of rainfall totals from the remnants of Ida:
...ALABAMA... OPELIKA 11.0 S 9.83 CENTREVILLE 6SW 6.35 WARRIOR LOCK AND DAM 6.15 CLANTON 5.69 SMITHS 5NW 5.54 BREWTON 3SSE 5.50 DEMOPOLIS LOCK & DAM 5.46 ATMORE 12N 5.41 WADLEY 1WNW 5.33 BREWTON 3ENE 5.20 LAFAYETTE 2W 5.10 USFS TALLADEGA 5.01 ...DELAWARE... GEORGETOWN 5.8 W 1.72 DOVER 6.4 WNW 1.65 MARYDEL 2.4 SE 1.47 SMYRNA 2.7 SSE 1.39 MIDDLETOWN 0.9 SSE 1.00 ...FLORIDA... GONZALEZ 2.5 NNW 6.78 PORT ST. JOE 0.6 SE 6.32 LAKELAND 1.5 W 5.75 CRESTVIEW/BOB SIKES 4.53 PENSACOLA RGNL ARPT 4.07 DE FUNIAK SPRINGS 12WNW 4.02 MOSSY HEAD 4.00 ...GEORGIA... COLUMBUS 15NW (GA POWER CO) 7.25 MANCHESTER 3.6 ENE 7.00 FORSYTH 6.0 NNW 6.86 WOODBURY 6.85 BERNER 0.4 ENE 6.62 DOUGLASVILLE 0.2 N 6.11 BOGART 4.2 SE 6.00 LA GRANGE 2.5 NE 5.96 WEST POINT 5.84 ATLANTA 5.67 ...MARYLAND... PARK HALL 0.2 SW 2.86 PATUXENT NAS 2.85 LEONARDTOWN 0.6 NE 2.71 RIDGE 1.0 N 2.47 HOLLYWOOD 1.5 NW 2.28 SALISBURY 3.7 SSE 2.20 BISHOPVILLE 3.1 E 2.07 PRINCESS ANNE 2.1 SSW 1.86 WALDORF 3.6 SSE 1.77 CAMP SPRINGS 0.1 ESE 1.68 ...MISSISSIPPI... WAYNESBORO 2W 4.13 WIGGINS 6E 4.11 ...NORTH CAROLINA ... SWANSBORO 3.3 NW 9.26 SNEADS FERRY 1.5 S 8.57 NEWPORT 0.2 SW 8.15 HAVELOCK 1.8 W 7.12 MOREHEAD CITY 6.0 WNW 6.96 ELIZABETHTOWN 6.2 NW 6.85 TRENT WOODS 1.3 SSE 6.57 MIDDLESEX 5.5 SSW 6.55 JAMES CITY 2.5 S 6.36 RALEIGH 4.5 NNE 5.10 ...NEW JERSEY... LOWER TWP 2.2 NE 1.18 LINWOOD 0.7 SSW 1.14 UPPER TWP 3.2 SE 1.08 MIDDLE TWP 4.4 SW 1.04 ESTELL MANOR 4.0 WNW 1.04 ...SOUTH CAROLINA... CLARKS HILL 2W 5.69 WALHALLA 1.5 NW 5.45 POMARIA 4.0 N 5.32 WEST UNION 1.5 ESE 5.14 SENECA 4.9 N 5.09 CLEVELAND 4S 5.08 GREENWOOD 0.5 SSE 4.91 NORTH MYRTLE BEACH 4.88 MARIETTA 1.8 SW 4.81 JACKSON 3.4 ENE 4.75 GREENVILLE/SPARTANBURG AP 4.24 ...TENNESSEE... MOUNT LECONTE 4.11 NEWPORT - FRENCH BROAD RVR (TVA) 3.62 COPPERHILL (TVA) 3.62 COSBY 3.44 GATLINBURG 2SW/PARK HQ (IFLOWS) 3.34 SEVIERVILLE/LITTLE PIGEON RIVER 3.33 DOUGLAS DAM (TVA) 3.31 GATLINBURG (TVA) 3.17 TELLICO PLAINS (TVA) 3.10 WILDWOOD (TVA) 3.06 OAK GROVE (TVA) 3.01 ...VIRGINIA... CHESAPEAKE 3.5 NE 6.60 VIRGINIA BEACH 1.2 SW 6.45 ROCKY MOUNT 3.6 W 6.25 BOONES MILL 12.6 E 5.80 MONETA 3.6 SW 5.79 ROCKY MOUNT 6.4 NE 5.72 COPPER HILL 6.2 S 5.55 JONES CREEK 5.52 MARROWBONE RESERVOIR 5.44 LYNCHBURG 2.5 NNW 3.75
-Dawn Brown
Ida Could Bring Flooding Rain
National Radar, (Old) Image; NOAA
Ida has finally made the transition to an extratropical cyclone (winter-type storm) this morning. Click here for the latest national radar imagery. Forecasters in Huntsville, Alabama, Atlanta, Georgia, and the Carolinas are following the storm. These areas could suffer from flooding rains over the next few days. Watch your local TV forecaster for the latest watches and warnings.
-Dawn Brown
High Winds, Heavy Rain… Ahead of IDA
Gulf Coast Radar, Image: NOAA Image is Old!
Click on the following link for the latest radar image of Ida. Ida continues to plow toward the Gulf Coast, creating high winds, and dumping heavy rain on Panama City, Florida, Mobile, Alabama and coastal areas outside of New Orleans, Louisiana. TV forecasters in those areas can give you the latest watches and warnings, and current position of Tropical Storm Ida. It appears the worst of the heavy rain is out ahead of the storm.
Ida Track, Image: NOAA click to enlarge
-Dawn Brown
Ida Weakens In Hostile Environment
Ida weakens due to wind shear, cold sea surface temps, and dry air. All hurricane warnings have been dropped. Tropical storm warnings from Louisiana to Florida. Isolated heavy rainfall along the northern Gulf Coast expected. It looks like Ida is transitioning from a tropical to an extra-tropical or winter-type low pressure system. High winds and isolated heavy rain will still be a problem.
9AM Update from National Hurricane Center:
The center of tropical storm Ida was located near latitude 26.5 North, longitude 88.3 West, or about 185 miles south-southeast of the mouth of the Mississippi river and about 285 miles south-southwest of Pensacola, Florida
Ida is moving toward the north-northwest near 17 mph. A turn toward the north and then to the north-northeast is expected over the next 24 hours. On the forecast track, the center of Ida is expected to make landfall along the northern Gulf Coast Tuesday morning. After landfall, a turn to the east is expected on Tuesday.
Maximum sustained winds continue to decrease and area now near 70 mph with higher gusts. Some additional weakening is expected today as Ida approaches the coast.
-Dawn Brown