Hurricane Issac skirts along the LA coast

Hurricane Issac made landfall early yesterday evening and then basically just stopped. It's been skirting along the Louisiana coastline essentially heading east all night maintaining its hurricane strength as it pumps heavy rain and wind into the city of New Orleans.

Complete radar track courtesy of Weather Underground

 



As the radar trace shows, once Issac reached the coast, it essentially turned a slight left and slowed down significantly. Forward motion decreased from 10 - 12 mph to 5 mph currently. Issac's direction is northwest right now which should bring the storm completely on land, however the shape of the coastline in this area allows a significant portion of Issac's strack to maintain at least part of this storm over water.

This morning, watching The Weather Channel, two things were quite apparent. First of all, the street flooding in the city did not seem too bad indicating that the drainage pumps were working as planned. The other key thing was the effect of the winds, especially when they were funnelled between tall buildings (venturi effect).

The image above is Jim Cantore of The Weather Channel fighting the worst of the winds. Dr. Cantore's report cvan be viewed on this link

Issac poses flooding threats for southeasatern Louisiana and southern Mississippi for the next few days at least but will eventually turn to the north. Then these heavy rains will bring much needed drought relief to the mid-west. The storm track continues to shift more to the west which will bring Issac's rains into Arkansas and possibvly eastern Oklahoma before turning east towards Indiana and Ohio.

Isaac: Major Flood Threat, Midwest Drought Relief (The Weather Channel)

Sometimes, tropical cyclones slow down or stall when moving ashore. Once the forward speeds slows, the rainfall potential of any tropical cyclone increases rapidly.  

This is particularly the case to the north and east of the cyclone's path, where deep tropical moisture can repeatedly be wrung out over a waterlogged area for hours, if not several days.  

We're not talking about, say, 2-4" of rain, either. In these persistent bands, that magnitude of rain would fall in just one hour. The U.S. record 24-hour rainfall, 43", deluged Alvin, Texas on July 25-26, 1979 during slow-moving Tropical Storm Claudette.  

In Isaac's case, eastern and southern Louisiana, as well as southern Mississippi will be in the epicenter of the heaviest rainfall totals. Over a foot of rain is expected in these areas, with local storm totals in excess of 20 inches! This includes the New Orleans metro area, which will give the city's pumps a stern test.  

This combination of heavy rain will pose an even larger danger near the coast of southeast Louisiana and southern Mississippi, where coastal flooding will potentially persist through early Thursday! There's simply no place for all this water to drain!

Hurricane Issac makes landfall

Hurricane Issac made landfall near Pass A Loutre State Wildlife Management Area at the southeastern tip of Louisiana. Issac had sustained winds of 80 MPH and gusts of 95 MPH as it came ashore.

Hurricane Isaac makes landfall in La. (Associated Press)

NEW ORLEANS (AP) -- Hurricane Isaac spun into the southern Louisiana coast late Tuesday, sending floodwaters surging and unleashing fierce winds as residents hunkered down behind boarded-up windows. New Orleans calmly waited out another storm on the eve of Hurricane Katrina's seventh anniversary, hoping the city's strengthened levees will hold. Isaac, a massive storm spanning nearly 200 miles from its center, made landfall at about 6:45 p.m. near the mouth of the Mississippi River. But it was zeroing in on New Orleans, about 75 miles to the northwest, turning streets famous for all-hours celebrations into ghost boulevards.

Hurricane warnings continue for southeast Louisiana, the MIssissippi and Alabama coasts up to the far western Florida panhandle. A flash flood warning exists for all of southeast Louisiana and south Mississippi. A tornado watch has also been issued for these areas.

Hurricane Warning in Southeastern Louisiana (Google Public Alerts)

A Hurricane Warning continues for the following locations: Washington, St. Tammany, Ascension, Livingston, Assumption. St. James, St. John the Baptist, Upper Lafourche, St. Charles, Upper Jefferson, Orleans, Upper Plaquemines, Upper St. Bernard, Upper Terrebonne, lower Terrebonne, lower Lafourche, lower Jefferson, lower Plaquemines, lower St. Bernard, northern Tangipahoa, Southern Tangipahoa, Pearl River, Hancock, Harrison and Jackson.  

For Marine interests, a Hurricane Warning continues for all of Southeast Louisiana and Mississippi Coastal Waters.  

A Tropical Storm Warning continues for the following locations: Pointe Coupee, West Feliciana, East Feliciana, St. Helena. Iberville, West Baton Rouge, East Baton Rouge, Wilkinson. Amite, Pike and Walthall.  

A Flash Flood Watch is in effect for all of Southeast Louisiana and South Mississippi. Please listen closely for any Flood Warnings that might be in effect for your area.  

A Tornado Watch is in effect for portions of Southeast Louisiana and South Mississippi. Please listen closely for any Tornado Warnings that might be in effect for your area.
 

Graphic courtesy of Weather Underground

 

Issac becomes a hurricane

Hurricane Issac continued its push towards Louisiana this afternoon having reached hurricane status at 12:20 EDT today. Dry air and particulates had been keeping Issac from strengthening but this has been overcome as a complete eyewall has formed around the center of Issac. As the radar image shows below, Issac has a full circulation of thunderstorms around its center as it continues its trek towards the shore.

Live Updates: Hurricane Isaac, Heading Toward Louisiana(AccuWeather)

Isaac has crossed the threshold at 12:20 p.m. EDT Tuesday, becoming a hurricane, while rolling toward the southern coast of Louisiana.  

An eye has formed with thunderstorms wrapping around the center of Isaac by noon Tuesday. During Monday afternoon and evening, dry air worked its way into Isaac, cutting off its flow of deep moisture, which put a halt to the thunderstorm activity on the north side of the storm.  

Dry air entrainment has been an issue with Isaac even as it entered the Caribbean.

TS Issac starts its march onshore

The outer rain bands of Tropical Storm Issac have started coming on shore this morning with the outermost band reachin across an arc from Mississippi to Georgia. Radar images are showing the tighter bands  of rain as the inner parts of the storm approach land.

Issac is poised right on the brink of becoming a hurricane. Surface winds have been measured only at 70 MPH but hurricane hunter aircraft have recorded windspeeds as high as 105 higher up. The central pressure from the storm has been dropping steadily since last night. All indications are that this storm should strengthen to a hurricane. Now that the storm is interacting with land, however, I am guessing that any further intensification will be minimal (and that is my uneducated guess).

Isaac makes its final approach towards Louisiana (Weather Underground - Dr. Jeff Master's Blog)

The winds and water are rising all along the coast from Louisiana to the Florida Panhandle as Tropical Storm Isaac makes its final approach. Two hurricane hunter aircraft in the storm are measuring a steadily lowering pressure and increasing winds aloft, but hurricane-force winds have not yet been observed at the surface. The 8:30 am center fix found a pressure of 976 mb, which is very low for a tropical storm. Top surface winds measured with the SFMR instrument were 70 mph, but the plane measured 102 mph at an altitude of 5,000 feet. It's more typical to see surface winds of 85 mph with a storm with these characteristics. Infrared and visible satellite loops and hurricane hunter reports from this morning have shown that Isaac has developed a 25-mile diameter eye, though the eyewall has not yet formed a full circle around the eye. Heavy thunderstorm activity is lacking on the north side, where light wind shear of 5 -10 knots is still pumping some dry air into the circulation.

Rain and the storm surge are the biggest threats with Issac and the heaviest effect will be in southeastern Louisiana and along the Mississippi and Alabama Gulf Coasts. AccuWeather is predicting that how the storm comes ashore could have a major effect on the level of flooding possible.
 

Isaac Not Another Katrina, But Still Dangerous UPDATED (AccuWeather)

Isaac is forecast by AccuWeather.com to make landfall as a hurricane in Louisiana Tuesday night and will bring the risk of storm surge flooding, inland flooding, damaging wind, tornadoes and beach erosion to part of the central Gulf Coast area.  

According to AccuWeather.com Hurricane Expert Dan Kottlowski, "The angle at which Isaac could come ashore could still drive a substantial amount of water inland over southeastern Louisiana and southern Mississippi."  

As a result a relatively weaker storm (up to a Category 1), when compared to Katrina (Category 3 at landfall in La./Miss.), could still pack a considerable punch.

TSR Storm Alert - Tropical Storm ISAAC

N Atlantic: Storm Alert issued at 28 Aug, 2012 9:00 GMT

 

Tropical Storm ISAAC (AL09) is forecast to strike land to the following likelihood(s) at the given lead time(s):

 

Red Alert Country(s) or Province(s)
    the United States
        probability for CAT 1 or above is 50% in about 21 hours
        probability for TS is 100% currently

Yellow Alert City(s) and Town(s)
    New Orleans (30.0 N, 90.1 W)
        probability for CAT 1 or above is 30% in about 21 hours
        probability for TS is 100% within 9 hours
    Mobile (30.7 N, 88.1 W)
        probability for TS is 95% within 9 hours
    Baton Rouge (30.5 N, 91.2 W)
        probability for TS is 95% in about 33 hours
    Pensacola (30.7 N, 87.0 W)
        probability for TS is 80% in about 21 hours
    Jackson (32.3 N, 90.2 W)
        probability for TS is 65% in about 21 hours
    Meridian (32.4 N, 88.7 W)
        probability for TS is 55% in about 45 hours

Note that
    Red Alert (Severe) is CAT 1 or above to between 31% and 100% probability.
    Yellow Alert (Elevated) is CAT 1 or above to between 10% and 30% probability, or TS to above 50% probability.
    CAT 1 means Hurricane strength winds of at least 74 mph, 119 km/h or 64 knots 1-min sustained.
    TS means Tropical Storm strength winds of at least 39 mph, 63 km/h or 34 knots 1-min sustained.

For graphical forecast information and further details please visit http://www.tropicalstormrisk.com/

This alert is provided by Tropical Storm Risk (TSR) which is sponsored by UCL, Aon Benfield, RSA Insurance Group, Crawford & Company and Aon Benfield UCL Hazard Research Centre.

North Gulf Coast Radar

Issac is still a tropical storm this morning but is slowly strengthening. With 71 MPH sustained winds, this storm is likely to intensify to hurricane status soon. This morning The Weather Channel was reporting that the storm was tightening up indicating that it would soon be stregnthening.

Either way - a strong tropical storm or a weak hurricane, the effect will be the same - heavy rain over the entire area. Mississippi can expect 15+ inches of rain with this storm and if the storm surge comes ashore during high tide, the wave heights can be as high as 12 feet. The key thing is to be prepared. This storm is a rainmaker and the storm stracks are showing the heaviest rain will likely go north into Louisiana,  Mississippi, and Arkansas with some bands coming further east. Alabama will probably get a fair amount of rain. It is my estimate that any rain from Issac in the Georgia area will be minimal.

At this point it looks like Issac is the type of storm we are looking for to fill up our lakes and releive the drought conditions we've all had all summer, but the rain will be heavy and flooding is always a major concern. So please be prepared.

Watch Isaac on Track for Direct Hit

Weather Channel Tropical Update on Issac

Isaac on Track for Direct Hit

Video:
Isaac poses a serious threat to portions of the northern Gulf Coast Tuesday and Wednesday. Hurricane warnings continue for New Orleans, Biloxi, and Gulf Shores.
http://link.brightcove.com/services/player/bcpid1543561897001?bckey=AQ~~,AAAAAAQxtuk~,N9g8AOtC12eobrWkZvrqKiXxOtGg-8h1&bclid=0&bctid=1282358292001

Tropical Storm Issac building strength; focusing on New Orleans

Tropical Storm Issac is still a tropical storm at the moment but is growing in strength and will likely be a hurricane during the night. Weather Underground is reporting sustained winds of 70 mph with some gusts reaching as high as 80 mph. Forward motion is currently at 10 mph and has been slowing. This will allow Issac to pull together and strengthen. Currently tropical storm force winds extend over 200 miles from the center of the storm. Issac is projected to grow to a category 2 hurricane with winds up to 100 mph.

Category 2 Hurricane Isaac projected to hit Louisiana coast south of New Orleans Tuesday afternoon: 4 p.m. update (Times-Picayune)

Tropical Storm Isaac is gaining strength over the warm waters of the Gulf of Mexico and is expected to reach Category 2 strength, with winds of 100 mph, as it hits the Louisiana coast at or just west of the mouth of the Mississippi River Tuesday afternoon. The forecast's slight nudge west of Isaac's track continues to put the more dangerous eastern side of the storm over the New Orleans area.

The entire New Orleans area remains under a hurricane warning. Forecasters with the Slidell office of the National Weather Service are predicting that tropical storm-force winds will be approaching central New Orleans by 4 a.m. Tuesday, with gusts approaching 82 mph as the center of the storm crosses Lake Pontchartrain on Wednesday at 7 a.m. Because of the long period of high winds, more than 24 hours, they warn of major electrical outages.

--snip--

"As Isaac comes ashore, it's going to be slowing down and somebody's going to get an awful lot of rain," said Hurricane Specialist Eric Blake, a native of Metairie, a 12-year veteran of the hurricane center. "The rain is right now approaching the mouth of the river and should strengthen overnight."

Isaac's unusually large size -- outer bands are dumping flooding rains on the east coast of Florida on Monday afternoon -- are believed to be one reason it has been slow to gain intensity, Blake said.
But that's changing, as seen by an increase in wind speed to 70 mph at 4 p.m., and another drop in its forward motion, to 12 mph, as it moves northwest toward the Louisiana coast from its present central Gulf of Mexico position 255 miles southeast of the Mississippi's mouth.

The storm appears to have a slight westward wobble in its track but all of the computer models are converging onto southeast Louisiana. This puts the dirty side of the storm over Mississippi and parts or all of New Orleans. It appears that the big threat from tis storm will be flooding from very heavy rain. Also the storm surge accompanying at Cat 2 storm as it makes landfall could be 6 - 12 feet along the Mississippi and Louisiana coasts.

Currently no mandatory evacuation is being ordered ahead of this storm, but anyone in the path of Issac should monitor its progress carefully and be prepared to evacuate or hunker down as recommended by the authorities.

Isaac Not Another Katrina, But Still Dangerous (AccuWeather)

While from a core meteorological standpoint Isaac will not be another Katrina in terms of intensity, it is still a dangerous storm.

Isaac is forecast by AccuWeather.com to make landfall as a hurricane in Louisiana and will bring the risk of storm surge flooding, inland flooding, damaging wind, tornadoes and beach erosion to part of the central Gulf Coast area.

According to AccuWeather.com Hurricane Expert Dan Kottlowski, "The angle at which Isaac could come ashore could still drive a substantial amount of water inland quickly over southeastern Louisiana and southern Mississippi."

As a result a relatively weaker storm (Category 1 or 2), when compared to Katrina (Category 3 at landfall in La./Miss.), could still pack a considerable punch.

Tropical Storm Issac entering the Gulf

Tropical Storm Issac left 8 dead as it crossed Haiti and drenched Havana and the Florida Keys over the weekend. Damage in the keys has been minimal but now Issac is entering into the warm Gulf waters and is expected to grow to hurricane strength over the next 24 hours.

The current track is sending Issac on a path towards New Orleans with SE Louisiana, Mississippi and Possibly Alabama getting the brunt of the storm.

Courtesy of Weather Underground

Isaac crossing Gulf with New Orleans in crosshairs (Associated Press)

Isaac blew past the Florida Keys and was rolling northwestward over the open Gulf of Mexico on Monday. The National Hurricane Center predicted it would grow to a Category 1 hurricane over the warm water and possibly hit late Tuesday somewhere along a roughly 300-mile stretch from the bayous southwest of New Orleans to the Florida Panhandle.

That would be one day shy of seven years after Katrina struck catastrophically in 2005, although Katrina was a much stronger Category 5 storm with winds over 157 miles per hour. Isaac is expected to have top winds of around 90 mph when it hits land.

The size of the warning area and the storm's wide bands of rain and wind prompted emergency declarations in four states, and hurricane-tested residents were boarding up homes, sticking up on food and water or getting ready to evacuate.

Issac is expected to grow to a Category 1 Hurricane before making landfall, however the storm's predicted track has been steadily moving west throughout the weekend. Issac was initially forecast to come ashore in Florida and that forecast has now shifted solidly into Louisiana with S. E. Texas being mentioned as potentially feling some effects from Issac.

Spaghetti Models are showing that the majority of computer models are converging on Louisiana and continue tp move westward. This graphic is updated regularly, so please check back thoughout the day to stay up to date with the storm's progress.

 

Courtesy: South Florida Water Management District

We're back to greet Issac

It's been over a year since I've posted to this blog. I've had some issues both on the personal front and the workfront that just became overwhelming and something had to give. I want to give a big thanks to all my loyal readers who continue to check the site for new and updated information. I know that the site keeps getting checked for information and with Issac heading for a landfall on the northern Gulf Coast, this would be a good time to get back in the saddle and get er going.

I also want to give a big thanks to Slipstream who gave us up to date and accurate reporting on all the activity happening in the western Pacific last year. It was a busy year last year and last month Hong Kong was hit with one of its strongest storms.

So everyone, as I get back to posting again, please leave comments letting me know if this information on storm activity, tracking and actions to take are valuable or if there is something I am missing. And of course if I mess up - call me out. We cannot improve unless we know what we are doing wrong. Remember I am just you humble hurricane hobbyist.