TS / Hurricane Isaac

tomcosgrave

This looks to be the first serious cyclonic system of the 2012 Atlantic Hurricane Season. At present, headed for the Carribean and perhaps Florida.

What looks troubling about this storm is that it could hit Haiti via the Dominican Republic which would be bad news for the impoverished population there.

premiercad

And a good chance of at least a TS begining to develop behind Isaac.

NOAA...
1. SHOWERS AND THUNDERSTORMS HAVE BECOME BETTER ORGANIZED IN ASSOCIATION WITH A LOW PRESSURE SYSTEM LOCATED ABOUT 650 MILES WEST-SOUTHWEST OF THE CAPE VERDE ISLANDS. ENVIRONMENTAL CONDITIONS APPEAR CONDUCIVE FOR A TROPICAL DEPRESSION TO FORM LATER TODAY AS THE LOW MOVES WEST-NORTHWESTWARD AT ABOUT 15 MPH. THIS SYSTEM HAS A HIGH CHANCE...90 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

tomcosgrave

Premiercad, that system is now TD Ten. NOAA predict that it will become a Tropical Storm, but at the moment do not forecast it going beyond that level of development - Isaac will prevent it from doing so because it is larger - wind shear caused by Isaac will retard development.

In terms of Isaac itself, the previous forecasts had it as a hurricane all the way to Florida, but have no corrected the forecast to show it will become a Hurricane just before it hits the Dominican Republic, then degrade to TS until well after it passes over Cuba before becoming a hurricane again as it hits Florida. It will be interesting to see how the system copes with Cuba, the mountain systems there can really impede a storm.

Meanwhile spare a thought for the people of Haiti, this will be very unpleasant for them.

maquiladora

The ECM is out on it's own with this idea, but for the past few runs it's been sending Isaac out into the Gulf of Mexico and up to the northern Gulf Coast as a major hurricane.



Long way off though and anything could happen yet but the ECM has a good track record with hurricanes.

premiercad

If it gets into the Gulf it would gain huge energy on it's sea track from Cuba before hitting land again..

maquiladora

Isaac is a bit of a mess at the moment. Recon flights have found multiple areas of circulation and barely any tropical storm winds.

A special Gulfstream IV jet will be doing a high altitude sampling mission this evening. The data from that will be put into the models so on Friday the models should show a more accurate forecast track.

irishgeo

its been a very quiet hurricane season.

Iancar29

Issac could make landfall to florida as a near Cat 1 Hurricane and possibly Cat 2 hurricane as it enters the Gulf Of Mexico

Iancar29

This sure would not be good!

Iancar29

Very cool animation (warning: large image may crash browser) of Tropical Storm Isaac's overshooting tops producing gravity waves.

http://cimss.ssec.wisc.edu/goes/blog/wp-content/uploads/2012/08/800x900_GOES_B1_RSRSO_ISAAC_animated_2012236_111500_182_2012236_134100_182_X.gif

tylercollins

Iancar29 wrote: »

This sure would not be good!

That would be more or less the same path as hurricane Irene last year?

maquiladora

Recon is flying in Isaac at the moment and still finding him to be a big mess. Winds are barely strong enough to support it being classified as a Tropical Storm and there is no single center of circulation. The weaker he stays the more westward he will lean, but it's really hard for the models to get a good handle on the track when there isn't even a clear center.

Down the road, Isaac has real potential to be a serious problem for someone, but at the moment he is a bit of an enigma.

Tomorrow's models should be a bit better because they will have data put into them collected from some special sampling missions done today.

Rikand

tropical storm "Joyce" going a little bit north for a US landfall ?

http://www.ssd.noaa.gov/goes/east/tatl/avn-l.jpg

Particularly with how close it is to isaac ?

maquiladora

Recon flight have found that the center of Isaac has relocated more than 100 miles further south than it's last official estimated position....

bamboozle

maquiladora wrote: »

Recon flight have found that the center of Isaac has relocated more than 100 miles further south than it's last official estimated position....

good news for the 400,000 living in tents in Haiti

Airports in Haiti and DomRep shut down for a few days i believe.

maquiladora

bamboozle wrote: »

good news for the 400,000 living in tents in Haiti

Airports in Haiti and DomRep shut down for a few days i believe.

Isaac is a large system so flooding will still be a problem for Haiti even if the center misses the island.

Still moving west now, winds up to 50mph, slowly getting into shape.

maquiladora

Winds up to 60mph, has started making a northwest turn. The center looks like it will pass over the far west, narrow part of Haiti.

Harps

The current ECMWF track has it making landfall just east of New Orleans as a minor hurricane

maquiladora

Recon has found that its strengthening, slowly but surely.

Should be 65mph and 995mb on the next update.

Could be a hurricane by the end of the night if that keeps up.

tylercollins

When is this due to hit?

maquiladora

5:00 PM EDT Fri Aug 24
Location: 17.2°N 71.9°W
Moving: NW at 16 mph
Min pressure: 994 mb
Max sustained: 65 mph

Rikand

tylercollins wrote: »

When is this due to hit?

hit where ? heh

Cuba Tomorrow and Sunday
Florida by Monday
New Orleans by Tuesday/Wednesday if it goes that direction/gets that far

tylercollins

It has hit Haiti today as a tropical storm. Just heard it briefly on the news so I know zero details on it.

maquiladora

tylercollins wrote: »

It has hit Haiti today as a tropical storm. Just heard it briefly on the news so I know zero details on it.

Only just daylight there so will be a while before they know how bad it was but I heard there are trees and powerlines down all over the country.

Isaac is currently going a bit more north of west than expected so he may only briefly pass over a small part of eastern Cuba and spend a more time over waters than previously expected.

The latest HWRF run is showing probably a worst case scenario for northwest Florida....



Scary that is only 78 hours away but hopefully it is wrong.

tylercollins

Here's an image from NOAA as well, predicted to go over the Florida Peninsula.

maquiladora

Isaac's position is already east of all the latest models.

Rikand

maquiladora wrote: »

Isaac's position is already east of all the latest models.

if thats the case - could it possibly keep going east and miss landfall on mainland USA altogether ?

Su Campu

The latest NHC discussion points to uncertainty in track due to probable Fujiwara interaction with another circulation centre. A slight westward shift in track would spare southwestern Florida somewhat, but could leave the door wide open for uninterrupted strengthening as it heads towards the Gulf Coast states.

THE INITIAL MOTION IS NOW 310/18. ISAAC IS CURRENTLY PART OF A
LARGE LOW/MID-LEVEL LOW PRESSURE SYSTEM COVERING THE NORTHWESTERN
CARIBBEAN SEA AND THE ADJACENT LAND AND OCEAN AREAS. THIS LOW
PRESSURE AREA HAS A SECOND VORTICITY CENTER BETWEEN JAMAICA AND THE
CAYMAN ISLANDS...AND FOR THE NEXT 24-36 HR ISAAC AND THIS CENTER
WILL LIKELY ROTATE AROUND EACH OTHER. BASED ON THIS EXPECTATION...
THE FORECAST TRACK SHOWS ISAAC MOVING NORTHWESTWARD FOR 12 HR OR
SO...FOLLOWED BY A TURN TOWARD THE WEST-NORTHWEST. IT IS POSSIBLE
THE STORM COULD MAKE A SHARPER TURN THAN FORECAST...AS THE UKMET IS
SHOWING AN ALMOST DUE WEST MOTION BETWEEN THE FLORIDA KEYS AND CUBA
NEAR THE 36 HR POINT. THE EARLY PART OF THE FORECAST TRACK IS
SHIFTED A LITTLE TO THE LEFT OF THE PREVIOUS FORECAST...BUT STILL
LIES TO THE RIGHT OF THE CONSENSUS MODELS AND THE BULK OF THE
DYNAMICAL MODELS. AFTER 36 HR...ISAAC SHOULD BREAK FREE OF OR
ABSORB THE REST OF THE LOW...WITH THE SUBTROPICAL RIDGE TO THE EAST
BECOMING THE DOMINANT STEERING INFLUENCE. THIS SHOULD ALLOW THE
STORM TO GRADUALLY TURN TOWARD THE NORTHWEST AND NORTH OVER THE
EASTERN AND NORTHERN GULF OF MEXICO...WITH AN EVENTUAL LANDFALL
ALONG THE NORTHERN GULF COAST IN 72-96 HR. WHERE THIS MIGHT OCCUR
IS STILL RATHER UNCERTAIN...WITH THE TRACK GUIDANCE SPREAD BETWEEN
SOUTHEASTERN LOUISIANA AND THE CENTRAL FLORIDA PANHANDLE. THIS PART
OF THE TRACK FORECAST LIES IN THE CENTER OF THE GUIDANCE ENVELOPE
NEAR THE CONSENSUS MODELS AND IS SIMILAR TO THE PREVIOUS FORECAST.

Harps

Still no real guidance on strength or intensity when it hits the US gulf coast

The latest HWRF forecast has it as a strong Cat 3 storm hitting northern Florida, the ECMWF wind scale only goes up to 74kts on wunderground so I can't tell how strong it is but also hitting northern Florida, GFS has it just east of New Orleans

Iancar29

Yes , very considerable shift west now on the models , not good for the gulf coast. Could turn into a reapeat of Katrina with the amount of potential strenghtenig over the warmer sees. Loos like the ECM was onto something . Shall be keeping a close eye on the NHC website this evening...

maquiladora

Yep, a big west shift on most of the models. Further west = more time over the Gulf bathwaters.

As a result of that some of the models really want to bomb it. New Orleans might be under the gun once again.



It's still only a 65mph storm at the moment though but there is the potential for something like that anyway.

maquiladora

Thought some of you might like this, I think it's fantastic.

http://www.ssec.wisc.edu/data/1min/

The GOES-14 weather satellite has been taken out of stand-by/storage mode and is taking rapid scans of Isaac every minute with 1km resolution.

One frame per minute and it is literally up to the minute! If you use the zoom feature and click in you can see fantastic smooth detail of the convention and cloud movements.

You can also choose water vapor/IR and change increase/decrease the number of frames in the loop in the options below.

tylercollins

I love this guys determination!

https://www.youtube.com/watch?v=f5-vgQDld1E

Can we please not use this young man as a source of entertainment.

M.T. Cranium

Isaac now well into radar range from Key West, FL

http://radar.weather.gov/ridge/radar.php?rid=byx&product=N0R&overlay=11101111&loop=no

(if looking in after midnight, go to "long range reflectivity" for a wider view and eventually choose other radar sites using the directional arrows, although for some time later Monday it may be out of all radar ranges in the east-central Gulf of Mexico.

My landfall prediction at this point would be eastern MS near Biloxi with a strong storm surge into Mobile Bay (Wed 1200 UTC or 0700h CDT local time).

maquiladora

The HWRF model just doesn't want to let up.

This would be on 7 years to the day that Katrina was bearing down on the Gulf Coast.

929 hPa



I think this model is overdoing it, but it's only a couple of days from now....

Latest ECM has it further east down to 950 on this chart, which in reality would probably be lower.



Edit : Looking on the Wundermap version of the ECM, it's down to 944 just off the coast from Pensacola.

Iancar29

Interesting Blog post ...

http://www.accuweather.com/en/weather-blogs/weathermatrix/isaac-turns-to-new-orleans-are-levees-ready/71023


EDIT :JUST NOW , New Orleans Mayor Mitch Landrieu declares a State of Emergency for the city as Isaac moves into the Gulf.

Harps

Still plenty of spread in track and intensity between models, worst case scenario seems to be the HWRF model which has it as a cat 4 hurricane aimed directly at New Orleans.

SnowDrifts

The 5pm NHC advisory seemed to delay the classification as a hurricane to Monday night which is surprising.

Min

À powerful Cat 2 hurricane is the prediction right now, but we have seen in the past how the NHC has underestimated the strength of the hurricanes once they enter the gulf.
My own prediction is it will bomb and become far more powerful than a Cat 2.

SnowDrifts

Seems to be building

http://www.ssec.wisc.edu/~rabin/goes14/loop_srso.html

sirpsycho

Wow, large cyclone!

sirpsycho

ps. Great link for the latest tracks and intensity forecasts. Not sure if anyone else posted recently:

http://ral.ucar.edu/hurricanes/realtime/plots/northatlantic/2012/al092012/

maquiladora

Latest recon has found pressure is down to 989, but there has been no increase in windspeed. Isaac just doesn't seem to be able to pull it together. The official forecast track is bad for New Orleans, but the intensity forecast has been downgraded to just a 90 mph Cat 1.

ninebeanrows

maquiladora wrote: »

Latest recon has found pressure is down to 989, but there has been no increase in windspeed. Isaac just doesn't seem to be able to pull it together. The official forecast track is bad for New Orleans, but the intensity forecast has been downgraded to just a 90 mph Cat 1.

I don't know, this still has upto 48hours of brewing time.

I think it is going to explode to life in the coming hours.

It's looking quite well on satellite imagery at the moment.

maquiladora

Recon flight says an eye is trying to form now. Should have visible sat soon as dawn breaks there.

Rikand

Eyewall replacement the cause of it looking a little disorganised mayhaps. Still expect this to gain significant strength

sirpsycho

edit: Opps, old image. No updated one yet.

No eye visible yet.

only one

Eye see what ye mean

maquiladora

Still 65mph. Pressure down to 988.

Recon saying that clouds and radar (on their plane) show an eye forming.

It's not an eyewall replacement because this thing has never had an eye yet. Still a tropical storm.

12:56 image : http://www.ssec.wisc.edu/data/1min/goes-14/2012/08/27/11/goes14_1_2012_240_1156.jpg

Microwave :

sirpsycho

They updated their microwave images now.

Appears to be something forming in the bottom left image?