Tsunami Watch Issued for Hawaii

A Tsunami Watch has been issued for the Hawaiian Islands as a result of a 7.9 magnitude earthquake that took place near Sulangan, Philippines a short while ago.



According to the Pacific Tsunami Warning Center, "a Tsunami may have been generated by this earthquake that could be destructive on coastal areas even far from the epicenter".



The bulletin goes on to say "if tsunami waves impact Hawaii the estimated earliest arrival of the first tsunami wave is 12:28 PM HST Friday".  That would be around 5:28 PM CDT today.



The location of the earthquake is noted by the yellow star on the above map, and I've noted the location of the Hawaiian Islands which are located in the upper right hand corner of the same map.



Folks in Hawaii take tsunamis very seriously, much like we do for tornadoes here in the lower 48 states.  According to information provided by the Pacific Disaster Center, tsunamis have accounted for more lost lives in Hawaii than "the total of all other local disasters".  Most of the deaths, 221 during the 20th Century, took place on the Big Island during the tsunamis of 1946 and 1960.  Both of those tsunamis were very large and caused widespread damage, but were triggered by earthquakes that took place much closer to the islands than the one this morning.



The most recent significant tsunami to strike Hawaii did so on November 29, 1975.  It was caused by an earthquake that took place just offshore of the Big  Island.  Waves were reportedly as much as 26 feet high with the associated tsunami.



The Pacific Tsunami Warning Center has promised hourly or more frequent updates as needed today, and we'll pass along any significant information that may come forward.

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Isaac, Though Weakening, Still Causing Many Problems...

Regular blog readers know that one of my greatest fears all along with Isaac (prior to landfall) had nothing to do with the wind, but the storm surge, and fresh water flooding.  Compounding that fear was the knowledge that the system would likely be moving very slowly, which would significantly extend the duration of the event, even longer than we saw with Katrina 7 years ago. Unfortunately, we continue to see those affects today, and are likely to for several more days to come...



Most recently we've heard of a mandatory evacuation affecting 50-60,000 people to the Northwest of New Orleans along the Tangipahoa River in Tangipahoa Parish (see the general location on the image below):

Officials in the area fear that a dam is close to being breached there, unable to hold back the waters that have been pounding the region from both the sea and the sky for the last 36 hours.  Radar estimates indicate that 15-20 inches of rain have fallen in this general area, and it is still raining at this time (although at a much lighter intensity, thankfully).

A similar order was issued yesterday evening for the southeast New Orleans community of Belle Chasse.  A levee was breached in that area, affecting approximately 3,000 people.  Plaquemines Parish (in which Belle Chasse is located) has been hit particularly hard by Isaac, with numerous rooftop rescues taking place yesterday.  The President of the Parish stated that the situation in his communities was "worse than Katrina".

Water hasn't been the only problem, as widespread wind damage has been reported as well.  Just under 1 million people are without power in Louisiana, which according to the Louisiana Public Utility Commission accounts for nearly 50% of all customers in the state.  Downed trees and other debris are widespread, which will slow the power restoration efforts in many areas.

Below are some new photos of the impacts of Isaac so far, with credits given where the photographer was able to be identified:

LaPlace, LA - Getty Images

Top of a 1 story home in Braithwaite, LA - Associated Press

Braithwaite, LA - Suzy Dinger

Damage in New Orleans - Times-Picayune

New Orleans - James Perry

Gulfport, MS - Tom Winter NBC News

Before & After in Fowl River, AL - Abby Weems

You can also view my post from yesterday for other photos.

Tornadoes have also been a problem in association with Isaac, as is often the case with tropical cyclones.  One county in Mississippi (Harrison) was under 10 different tornado warnings during the day yesterday.

Most tornadoes in association with tropical systems are relatively weak and short lived, but can cause damage, injuries or even death if they strike a populated area.  One tornado in Pascagoula, MS was on the ground long enough to be captured on camera yesterday:

Additional tornadoes are possible today, and a Tornado Watch is currently in effect for portions of Mississippi, Alabama and the western Florida panhandle:

Not all of the news with Isaac is bad, however.  While heavy rains will continue to cause problems across portions of Louisiana and much of Mississippi and western Alabama today, much needed rain will fall over the drought stricken Midwest as the remnants of Isaac spread Northward over the weekend:

For additional information, including the latest satellite and applicable radar imagery, etc., please check out the dedicated page on our sister site, WeatherGuidance.com.

For more information from the Original Weather Blog, including "live blogging" during rapidly changing weather events, please be sure to follow me on facebook and/or twitter:

 

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Isaac Weakening (and moving) Very Slowy; Significant Impacts Continue...

Based on radar data at 5pm CDT (see below), the center of Tropical Storm Isaac was located between Convent and Donaldsonville, LA.  This is about 50 miles West of New Orleans.  Isaac continues to move very slowly toward the North/Northwest to Northwest at around 5 mph.  Maximum winds have decreased to around 70 mph, which resulted in the "downgrade" to Tropical Storm earlier this afternoon.  Despite the change in classification, Isaac is still causing widespread problems across the state of Louisiana as well as southern Mississippi, and this will continue into the night and early Thursday.

As you can see on the most recent radar presentation, the eye has become very small and will continue to slowly dissipate this evening.  Strong winds of 50-60 mph with gusts of 70-80 mph continue mainly to the East and Northeast of the center.  Winds will remain strong throughout the evening, but will gradually decrease into the 40-50 mph with gusts of 50-60 mph range by Midnight.

In addition to the widespread damaging winds of the last 12-18 hours, the other big story with Isaac, just as we feared, has been the pro-longed storm surge and related flooding.  I could bore you with some factual details, but I think the pictures below tell the story much more effectively (credit given when the photographer was known):

Pass Christian, MS - Riann Martin

Gulfport, MS - Riann Martin

French Quarter - Tripp Remmington III

Gas Station in Braithwaite, LA - Associated Press

McDonald's Near Braithwaite, LA - Charley Louise

Taken from 3rd story of a Braithwaite, LA Home - Unknown Photographer

More Rooftops in Braithwaite, LA - Lolo Jones

Lake Pontchartrain Overflowing - AP Photo

Beau Rivage Resort in Biloxi, MS - Sun Herald

Laplace, LA - Richard McDougle

Historic Home Destroyed in New Orleans - Melissa Perry

In addition to the persistent (though gradually decreasing) strong winds, additional heavy rainfall is on tap for much of the region tonight.  Here is how the rainfall is forecast to break-down for the periods 7pm to 1am CDT, 1am to 7am CDT and 7am to 1pm CDT tonight and tomorrow, respectively:

While several tornadoes have been reported today, it is unclear how much damage was caused by any actual tornadoes vs. the ongoing windstorm.  A Tornado Watch continues across much of the region until 12 Midnight this evening, and may be extended and/or reissued as Isaac continues to slowly move Northward:

For additional information, including the latest satellite and applicable radar imagery, etc., please check out the dedicated page on our sister site, WeatherGuidance.com.

For more information from the Original Weather Blog, including "live blogging" during rapidly changing weather events, please be sure to follow me on facebook and/or twitter:

 

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Isaac Still Battering Louisiana and Mississippi...

As feared, Hurricane Isaac continues to move at only a snail's pace across extreme southern Louisiana, producing widespread flooding rain, dangerous storm surge and damaging winds across the region.

Wind gusts have exceeded 50 mph for 13 hours straight at the New Orleans Naval Air Station.  Gusts over 60 mph have been recorded for 10 hours straight now, and there have been 5 hours within that time period with wind gusts over 70 mph.  Unfortunately, the winds will not subside for a number of hours more, as Isaac just lumbers along to the West or Northwest.

Dangerous storm surge flooding also continues across southeast Louisiana and southern Mississippi.  The President of Plaquemines Parish is reporting that people are "trapped on rooftops..." due to the 12 foot levee being overflowed there.  He said its "worse than Katrina".  Of course, many of you will remember that it was exactly 7 years ago today that Katrina was battering the same region.  Katrina was moving rather quickly, but Isaac's very slow motion means that additional wind-whipped flooding is likely across the region today and tonight.

Storm Surge Flooding in Braithwaite, LA

AP Photo of Flooded Area Near Lake Pontchartrain

In addition to the storm surge flooding and inundation threat, fresh water flooding will also be a continued hazard across the region.  Over 10 inches of rain will fall through today and tonight across a large portion of southcentral and portions of central Louisiana:

Isolated tornadoes will also be a continued threat, primarily to the East and Northeast of the center of the system.

As I alluded to above, strong, damaging sustained winds and gusts in excess of hurricane force will continue across much of southeast Louisiana and portions of southern Mississippi for much of the day today.  Based on the present location and expected movement of Isaac, hurricane force winds and gusts should end during the late afternoon or early evening hours, but tropical storm force winds and higher gusts will continue well into tonight across much of the region.

Beyond Louisiana, Isaac is forecast to move slowly toward the North, to the West of the Mississippi River, through the end of the week and the remnants will reach the Midwest over the weekend:

Some computer models are forecasting a more Westerly track, however the above National Hurricane Center (NHC) track assumes that the system will be drawn Northward around the Western edge of an area of high pressure in the middle and upper atmosphere, and I agree with that assessment at this time.  

Beneficial though at times heavy rains will spread along and ahead of the track of Isaac into the Midwest over the weekend, with amounts in excess of 3-6 inches possible (see the rainfall graphic 2 images above).

For the latest imagery and updates on Isaac, please refer to this dedicated webpage at our sister site, WeatherGuidance.com.  I will also post various shorter updates with additional images, etc., on both facebook and twitter throughout the day today and tomorrow.  If you would like to receive those updates, please be sure to follow me there if you aren't already:

 

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Outer Bands of Hurricane Isaac Reaching New Orleans...

Some of the outer spiral bands of Hurricane Isaac are spreading into the New Orleans area at this time, as you can see by the above radar image.  This trend will continue, and increase, throughout the day.

"Wait a minute, Rob - Isaac is a Tropical Storm, not a hurricane..." you say?  Wrong.  Isaac is a hurricane, it just hasn't been classified as such by the National Hurricane Center (NHC).  

With satellite presentations like this:

...and 80 mph winds being measured in a recent aircraft pass, surely and undoubtedly the NHC will finally decide to call Isaac what he has been since yesterday on the upcoming 10am advisory, but  I have given up trying to figure out what they are going to do.



The "official" classification is really irrelevant for purposes of our discussion, because if it looks like a pig and smells like a pig... you know the rest.  Where it is not irrelevant, however, is in the realm of public safety and preparedness.  You can have a "Hurricane Warning" up for as many areas as you want for as long as you want, but until the system in question is actually called a "Hurricane" by the government, some people, and in some cases, some county and municipal government agencies, won't act, or won't act in the same way that they would if the system were called a hurricane.  In a situation like this, with a storm surge of potentially disastrous levels likely to take place in the effected areas, I think the classification situation has been handled poorly so far.  



Ok, I'll get off of my soap box now and get back to the particulars on Hurricane Isaac:



The white arrow in the radar image back up at the top of the post shows the rough position of the center of Isaac as of 9am.  This is about 145 nautical miles Southeast of New Orleans.  Isaac has continued to move toward the Northwest at 7 mph for the last several hours, and this general motion is likely to continue today.  If anything, the system may actually slow its forward speed even further later today, which will make an already bad situation (with respect to storm surge, wind duration and flooding) even worse by tonight and early Wednesday.



The one thing that I do agree with the NHC on at this time is the track of the center, which is forecast to pass over or very near New Orleans late tonight or during the pre-dawn hours of Wednesday morning:

With a system as large as Isaac, it is important not to focus solely on the location or path of the center.  At this time, tropical storm force winds extend outward up to 205 miles from the center, and by the time landfall of the center takes place tonight, hurricane force winds will likely extend up to 100 miles or more from the center.

Due to the slow movement of Isaac, tropical storm and hurricane force winds will be felt across the Hurricane Warning area for an extended period of time, possibly 12-18 hours in some locations.  This, coupled with torrential rains and a long duration storm surge will create extremely dangerous, life threatening conditions from the coast of southeast Louisiana, across the New Orleans area, into southern Mississippi and portions of southern Alabama.

Tropical storm force winds will be felt along the coast of the above mentioned areas as early as this afternoon, with hurricane force winds likely later this evening and into tonight.

Similar to my concerns about the "tropical storm vs. hurricane" classification, I am also afraid that too many folks are focusing solely on the wind speed forecast with Isaac.  While a 90-100 mph hurricane will cause plenty of wind damage (and some models are still suggesting that winds will be even higher by the time of landfall), my main concern here for several days has been the storm surge and flooding potential, due to the way that Isaac will come in (with respect to the orientation of the center vs. land, etc.).  Here is the latest forecast for the storm surge impacts across the region:

As you can see, nothing has really changed.  Extreme storm surge and flooding impacts are expected within a large area of southeast Louisiana (including the New Orleans area), then Eastward along the Mississippi and Alabama coasts.  Not only will water levels be high as Isaac pushes waters from the Gulf of Mexico into the region, but this will last for a very long time, much longer than we saw with Katrina (due to the slower movement of Isaac).  I sincerely hope that the modifications that were made to the levee system over the last few years come through and do their job.

In addition to the storm surge from the sea, widespread fresh water flooding will also take place across the region due to very heavy rainfall.  Rainfall amounts in excess of 10 inches can be expected not only across southeast Louisiana, but also much of southern Mississippi and extreme southwestern Alabama:

As is typically the case with a landfalling tropical system, isolated to scattered tornadoes will also be possible, particularly to the East and Northeast of where the center makes landfall.

I hope that folks across this region are prepared for what is coming later today through Wednesday.  If you are still in the area, particularly the New Orleans area, southeast Louisiana and southern Mississippi, and have been debating whether or not to move inland, I strongly suggest that you do so immediately.  Most of the major computer forecast models suggest that rapid intensification is likely prior to landfall tonight as the center still has plenty of warm, previously undisturbed waters to travel across.  As I mentioned above, the winds are only one factor here, as the storm surge and flooding will be widespread and of a very long duration.  Conditions are likely to become very bad or worse before you have time to react, so please take the "better safe than sorry" approach.

For the latest imagery and updates on Isaac, please refer to this dedicated webpage at our sister site, WeatherGuidance.com.  In addition to more frequent posts here on the blog today and Wednesday, I will also post various shorter updates with additional images, etc., on both facebook and twitter.  If you would like to receive those updates, please be sure to follow me there if you aren't already:

 

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