Isaac approaching hurricane strength

By: Angela Fritz , 9:14 PM GMT on August 27, 2012

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Isaac is walking the line of hurricane status this afternoon after a hurricane hunter mission investigated the storm and found winds of 80+ mph with the SFMR instrument, which looks down at the surface from the plane and estimates what wind speeds are. This instrument has a notoriously rough time in doing so when there's heavy rain, and since the strongest winds were recorded coinciding with the strongest rain, you can imagine that this region of high wind speed could be suspect. The hurricane hunter mission is still in the storm, so I imagine they will issue a special update if needed. Currently the best estimate of wind speed within the storm is 70 mph. Isaac's pressure has been dropping today as well and is now 981 mb. Isaac is moving northwest at 12 mph--no change since this morning. Satellite loops show that Isaac remains large, though asymmetric, with most of the strong thunderstorm activity on the west and southwest side. Isaac's southeast side continues to struggle with dry air and wind shear, which could help to moderate Isaac's intensity as it approaches the coast.

An oil platform in the northern Gulf of Mexico is reporting sustained winds from the north-northeast at 40 mph this afternoon. A buoy west of Tampa, Florida is recording sustained winds around 30 mph, and platforms south of Louisiana are recording winds from 35-40 mph. The widespread heavy rain of yesterday has lightened up in Florida, but a strong line of thunderstorms in one of Isaac's outer bands is training northward along and offshore of the east coast of Florida, affecting everyone from Miami to Jacksonville.

This afternoon the AP reported that Isaac's death toll in Haiti jumped to 19, which puts Isaac's total death count at 21. It appears most of the deaths in Haiti were due to collapsing structures.


Figure 1. Satellite imagery of Tropical Storm Isaac around 3pm EDT on Monday.

Track forecast:
Models seem to be coming into better agreement today on where Isaac will make landfall, closing in on Louisiana and New Orleans as most likely landfall point. The ECMWF, HWRF, and UKMET all suggest New Orleans as the landfall location. The GFS is only slightly west of that. The GFDL is the farthest west, predicting landfall near the Louisiana-Texas border. Landfall timing remains Tuesday night. Beyond landfall, Isaac is expected to move north toward the Midwest through the rest of this week, however, models are showing that the system will likely slow down around landfall time, prolonging impacts like surge and inland flooding.

Intensity forecast:
The closer Isaac gets to landfall without having formed an eye, the better it is for intensity at landfall. Isaac has strengthened only modestly in the past 24 hours, and is still struggling with a less-than-conducive atmospheric environment. The HWRF remains on the high end of the intensity spectrum, suggesting Isaac will be a weak category 2 upon landfall. Other models suggest it will be a strong category 1, but the difference is splitting hairs. The National Hurricane Center's official forecast is for Isaac to continue strengthening over the next day, reaching category 2 at landfall.


Figure 2. Tide gauge data from St. Petersburg, Florida. The green line shows the storm surge. As Isaac's counterclockwise winds blew offshore this morning, water levels feel two feet at St. Petersburg. The winds switched to onshore this afternoon as the center of Isaac moved more to the northwest, bringing a storm surge of two feet to the city.

Storm surge observations from Isaac
This morning, as Isaac's counter-clockwise winds brought offshore winds to the Tampa/St. Petersburg area, ocean waters fell two feet along the coast. This afternoon, winds have shifted to blow onshore, and a two foot storm surge has been observed at Naples, Fort Meyers, and St. Petersburg on the west coast of Florida. Water levels have also begun to rise along the coast of Louisiana, with a storm surge of 1.5 feet already occurring at Shell Beach on the east side of New Orleans in Lake Borgne.

Angela and Jeff

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3304. Patrap
ISAAC RainbowTop Loop

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Hurricanes Thrive off of moisture ....

It as if Isaac has spent it's whole life over the top of Dry Air
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Quoting MississippiWx:
Well, Isaac seems to finally have his act together. He will strengthen all the way through landfall.

Which is not good wind wise for NOLA and since Isaac is larger it will take him longer to weaken.
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Hey JasonRE - just saw this posted in the Advertiser's site:

Lafayette Consolidated Government is activating four sandbag sites today. The sites will open by noon and are at the following locations:
-LCG North District Barn 130 Shantel Road (old landfill)
-LCG South District Barn 1017 Fortune Road
-George Dupuis Center (Brown Park) 1212 E. Pont Des Mouton Road
-Robichaux Center (Neyland Park) 1919 Eraste Landry Road
Sand and shovels will be provided a these locations and residents will be required to fill their own bags (self-service). Lafayette Consolidated Government will provide the bags.
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3300. zawxdsk
Quoting Masquer08er:
Best estimate, what time will landfall happen? Just heard president say he was told later today. I was thinking tomorrow morning.


Depends if you consider the little 60 mile jut of Mississippi River Delta land or not. He could may landfall there as early as 7 pm, but at 6 to 7 mph, it might be 3 am to hitting mainland Louisiana.
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Product: NOAA Vortex Message (URNT12 KWBC)
Transmitted: 28th day of the month at 14:15Z
Aircraft: Lockheed WP-3D Orion (Reg. Num. N42RF)
Storm Number & Year: 09L in 2012
Storm Name: Isaac (flight in the North Atlantic basin)
Mission Number: 30
Observation Number: 23
A. Time of Center Fix: 28th day of the month at 13:39:21Z
B. Center Fix Coordinates: 28°00'N 88°30'W (28.N 88.5W)
B. Center Fix Location: 166 miles (267 km) to the SE (145°) from New Orleans, LA, USA.
C. Minimum Height at Standard Level (Undecoded): NA NA
D. Estimated (by SFMR or visually) Maximum Surface Wind: 58kts (~ 66.7mph)
E. Location of the Estimated Maximum Surface Wind: 49 nautical miles (56 statute miles) to the NE (42°) of center fix
F. Maximum Flight Level Wind Inbound: From 124° at 84kts (From between the ESE and SE at ~ 96.7mph)
G. Location of Maximum Flight Level Wind Inbound: 56 nautical miles (64 statute miles) to the NE (43°) of center fix
H. Minimum Sea Level Pressure: 977mb (28.85 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 15°C (59°F) at a pressure alt. of 2,461m (8,074ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 19°C (66°F) at a pressure alt. of 2,456m (8,058ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 14°C (57°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Open in the southwest
M. Eye Shape: Elliptical (oval shaped)
M. Orientation of Major Axis in Elliptical Eye: 130° to 310° (SE to NW)
M. Length of Major Axis in Elliptical Eye: 25 nautical miles (29 statute miles)
M. Length of Minor Axis in Elliptical Eye: 20 nautical miles (23 statute miles)
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: Other - Not surface, 1500ft, 925mb (if vortex is newer than about mid 90's; see note for more), 850mb, 700mb, 500mb, 400mb, 300mb or 200mb
Remarks Section - Remarks That Were Decoded...
Maximum Flight Level Wind: 84kts (~ 96.7mph) in the northeast quadrant at 13:25:42Z
Maximum Flight Level Wind Outbound: 59kts (~ 67.9mph) in the southwest quadrant at 13:51:05Z
Maximum Flight Level Temp: 19°C (66°F) which was observed 7 nautical miles to the NE (52°) from the flight level center
Remarks Section - Additional Remarks...
SEC MAX FL WIND 68 KT BRNG:43 deg RNG:96 nm
Member Since: April 29, 2009 Posts: 75 Comments: 14073
3298. GetReal
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3296. Pastey
Denham Springs city council just created a dusk-to-dawn curfew starting now until Friday excluding workers both utility and emergency, those going to and from work and those traveling to "help". "Help" is up for interpretation so if you don't have to go somewhere, I recommend staying home. If you do go, be ready to be stopped and explain your traveling. Be safe and be SMART people. Don't go out sightseeing because you're bored. Let's keep the streets clear so that work crews can move around efficiently.
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Quoting Patrap:


Word.

But then again, Hockey and well, alcohol comes to mind.

: P



i hop you are all boarded up pat with the windows so i would be get the last few things done why you can then chating here on the blog lasting time
Member Since: May 21, 2006 Posts: 5091 Comments: 114783
Well, Isaac seems to finally have his act together. He will strengthen all the way through landfall.
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3293. hydrus
Storm tracks so far ..
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Choctawatchee Bay just north of destin has risen maybe a foot in the past hour.
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Quoting Tropicsweatherpr:


That update was released at 8:19 AM EDT. We know after that time what the new data has revealed.


Do they go with GMT or UTC with those times? Would make sense since they release updates saying it came out at 12pm and it's only 9am.
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Quoting dogsgomoo:
You know... I'm not that old but I recall a time when live weather events and emergency news preempted most commercials and regular programming. But i guess when you're TWC and you want to treat everything as if it was an emergency and Cat 42 equivalent (complete with dramatic music) you'd never air another commercial again. ;)


You couldn'tve said it better! This last commercial break Norcross had plenty of notice before the break - however if I worked there and was in the middle of an on air analysis and was cut to commercial I'd be cussing somebody out in Master Control or the director. Unbelievable...
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Quoting Patrap:
Never be concerned about "landfall"..as at that time the Storm is fully half inland with effects already occurring Hours before that misused TERRIBLE wording.

My strongest objection always stated.

And a Fact.

So naaaaaaaaa.

: )
It probably means more for Isaac, since most of his convection is S of the center.
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Quoting Charmeck:

Get real!! It was 170 miles from the mouth of the Mississippi at 7:00 EDT and traveling at 10 mph so it looks to me like it will be 17 hours before landing.


Its 80 miles from Burwood Bayou (closest point of land)
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Definitely the calm before the storm here in Mandeville. I plan on taking my GoPro out to the lake in a little while to see what is going on out there.
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3285. Patrap
Quoting Tazmanian:



the NHC norml dont go with D



some time they go with what fight level says


Word.

But then again, Hockey and well, alcohol comes to mind.

: P
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Quoting Charmeck:

Get real!! It was 170 miles from the mouth of the Mississippi at 7:00 EDT and traveling at 10 mph so it looks to me like it will be 17 hours before landing.


at 7 Am it was moving at 7 MPH according to NHC, I think that was conservative. His moving at a snails pace
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3283. mod4
Longtime reader, first time poster.

St. Augustine, FL here. We did not get near the rainfall totals that south and central Florida did.

I enjoy getting thoughts from many different folks on weather events.

Lived here since '74, have been through a few storms (never have left) with 2004's three TS in a row actually being the worst personally.
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Anyone know if it's actually raining in the greater NOLA area? or is the radar just out to lunch?

I ask because radar shows some light showers approaching my location.


I figure between the cable company, Intergy,and my own house, it's only a matter of time now before something breaks and I won't be on here any longer.

But maybe you NOLA people lose power first so I'll know ahead of time if the post rate drops to nothing.
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3281. Patrap
Never be concerned about "landfall"..as at that time the Storm is fully half inland with effects already occurring Hours before that misused TERRIBLE wording.

My strongest objection always stated.

And a Fact.

So naaaaaaaaa.

: )
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Hello Everyone - I live on Plash Island in Gulf Shores, AL. We are located on the north bank of the ICW where it empties into Bon Secour/Mobile Bay. We are north of the Ft. Morgan Peninsula. My concern is storm surge. Can anyone tell me what we can expect as far as surge goes? My thought is that with the wind out of the east and southeast, that the water would pile up more on the western side of Mobile Bay, say around Bayou la Batre. I appreciate any input. TIA!
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Quoting Orcasystems:


From the Vortex report

D. Estimated (by SFMR or visually) Maximum Surface Wind: 60kts (~ 69.0mph)



the NHC norml dont go with D



some time they go with what fight level says
Member Since: May 21, 2006 Posts: 5091 Comments: 114783
Quoting Orcasystems:


From the Vortex report

D. Estimated (by SFMR or visually) Maximum Surface Wind: 60kts (~ 69.0mph)


From the Drosponde report, straight from the surface.
Significant Wind Levels...
Level Wind Direction Wind Speed
988mb (Surface) 195° (from the SSW) 70 knots (81 mph)
983mb 190° (from the S) 67 knots (77 mph)
970mb 185° (from the S) 77 knots (89 mph)
939mb 190° (from the S) 81 knots (93 mph)
909mb 195° (from the SSW) 74 knots (85 mph)
896mb 200° (from the SSW) 67 knots (77 mph)
850mb 210° (from the SSW) 64 knots (74 mph)
752mb 220° (from the SW) 54 knots (62 mph)

And..
Maximum Flight Level Wind: 89kts (~ 102.4mph) in the northeast quadrant at 13:17:00Z
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Quoting aasmith26:


That REALLY made me angry. How unprofessional of TWC if I was Norcross, i'd be rather angry...
You know... I'm not that old but I recall a time when live weather events and emergency news preempted most commercials and regular programming. But i guess when you're TWC and you want to treat everything as if it was an emergency and Cat 42 equivalent (complete with dramatic music) you'd never air another commercial again. ;)
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3276. hydrus
72 hours..
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Quoting CybrTeddy:
Wow, they might actually no upgrade Isaac to a hurricane. I'm interested to hear their reasoning to disregard the dropsonde data if so.
AL, 09, 2012082812, , BEST, 0, 278N, 882W, 60, 976, TS


That update was released at 8:19 AM EDT. We know after that time what the new data has revealed.
Member Since: April 29, 2009 Posts: 75 Comments: 14073
Quoting GeorgiaStormz:


its gonna half to stall now, its nearly on grand isle already

Get real!! It was 170 miles from the mouth of the Mississippi at 7:00 EDT and traveling at 10 mph so it looks to me like it will be 17 hours before landing.
Member Since: August 21, 2011 Posts: 0 Comments: 143
Quoting JasonRE:
Well I guess this storm isn't as serious as I've been reading about. Our company in Lafayette has us open tomorrow for business. Am I losing my mind? I've been tracking this thing since it began and now I'm going to have to sit through this at work? It sure as hell doesn't seem to bother the owner enough.


Your workplace will *probably* be cancelled tomorrow AM, they usually make that decision come early once they really know where it is going as Isaac will be approaching landfall. I doubt they're going to make you drive to work in TS force winds. My transmitter in my car blew out during TS Debby at that was only in 40mph sustained.
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Quoting CybrTeddy:
Wow, they might actually no upgrade Isaac to a hurricane. I'm interested to hear their reasoning to disregard the dropsonde data if so.
AL, 09, 2012082812, , BEST, 0, 278N, 882W, 60, 976, TS


From the Vortex report

D. Estimated (by SFMR or visually) Maximum Surface Wind: 60kts (~ 69.0mph)
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My thoughts and prayers with all in the path of Isaac. I hope the levees doesn't break this time.
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Quoting ILwthrfan:


Edit sorry. Officially he has moved .18 degrees North and .28 degree West in the last hour since Recon has investigated.


Should pass over 30N 91.6W then, unless it corrects to the north again.

Closest approach to NOLA will be a tad SE of there, but NOLA would get the eastern eye wall, not much difference either way between WNW and NW for now...
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Quoting CybrTeddy:
Wow, they might actually no upgrade Isaac to a hurricane. I'm interested to hear their reasoning to disregard the dropsonde data if so.
AL, 09, 2012082812, , BEST, 0, 278N, 882W, 60, 976, TS

Hmmm, that would be interesting. I still think it a hurricane and recon is going for another fix.
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3268. hydrus
Wave train going strong..
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Quoting hydrus:
This is a clickable wind map. Click anywhere to find the windspeed. Highest I found was 58 mph..Link


Nice thanks. :)
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3266. Wiebel
Pretty impressive forecasted Surge with thisone.

Predicted surge is well below the threshold levels of the new 1:100 year NOLA Surge barriers although you can never rule out weak spots.

Interesting to see that the surge models haven't incorporated the Great Louisiana wall yet. They still predict a significant surge behind the wall, and I dont think it is open right now is it?
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To my friends East. Take care and good luck!!! We will be praying for a weak storm and everything will work out fine. You guys are always welcome to hag out in Texas.

For anybody trying to bring Issac West to Texas, here is what the local NWS says:

FORECAST FOR TODAY
REMAINS RELATIVELY UNCHANGED AS DRIER MID LEVEL AIR IS EXPECTED TO
WORK INTO THE REGION. THIS WILL ALLOW TEMPERATURES TO WARM INTO
THE MID TO UPPER 90S ACROSS MOST OF SOUTHEAST TEXAS THIS
AFTERNOON. HAVE KEPT SLIGHT CHANCE POPS IN PLACE AS LOW LEVEL
MOISTURE REMAINS PRESENT BUT COVERAGE IS EXPECTED TO BE FAIRLY LOW
ACROSS THE REGION.

THE FORECAST FOR THE NEXT SEVERAL DAYS REMAINS RELATIVELY
UNCHANGED AS TROPICAL STORM ISAAC IS EXPECTED TO MOVE INLAND
ACROSS SOUTHERN LOUISIANA EITHER LATE TONIGHT OR EARLY WEDNESDAY
AND TRACK TO THE NORTH NORTHWEST. THE 00Z GFS REMAINS RELATIVELY
UNCHANGED FROM ITS PREVIOUS TRACK ALTHOUGH THE ECMWF NOW BRINGS
THE SYSTEM A BIT FURTHER TO THE WEST...SIMILAR TO PREVIOUS GFS
RUNS. FURTHERMORE...DATA FROM AN AIR FORCE HURRICANE HUNTER
AIRCRAFT SHOW THAT THE CENTER OF ISAAC HAS WOBBLED TO THE WEST
OVER THE LAST SIX HOURS. THIS WESTWARD SHIFT IS EXPECTED TO BE
TEMPORARY BUT BASED UPON THIS MOTION THE TROPICAL STORM WATCH HAS
BEEN EXTENDED WESTWARD TO INCLUDE PORTIONS OF THE UPPER TEXAS
COASTLINE EAST OF HIGH ISLAND. WITH THE LATEST ECMWF TRACK AND
THIS WESTWARD JOG HAVE DECIDED TO INCREASE POPS SLIGHTLY ACROSS
OUR FAR EASTERN COUNTIES FOR THE NEXT SEVERAL DAYS AND ALSO LOWER
MAX TEMPS GENERALLY ACROSS AREAS ALONG AND EAST OF INTERSTATE 45.
WHILE ISAAC IS NOT EXPECTED TO DIRECTLY THREATEN OUR CWA...ANY
FURTHER SHIFT WESTWARD IN TRACK WOULD NECESSITATE ADDITIONAL
CHANGES TO POPS AND TEMPS LATER TODAY OR TONIGHT BEFORE THE SYSTEM
MOVES INLAND.

So maybe Communities such as Orange or Beaumont *MIGHT* see a little bit, chances are we are in store for some HOT weather as the storm moves off to the east of us.

I am glad for the previous rain we have experienced this summer. Last year at this time we are under that Death Ridge that brought 105 Degree temps that really caused Fire problems to the point we had fires so close to Houston that smoke was visible from my office in The Woodlands. So lets enjoy the Hot but less humid air and pray for our neighbors to the East.
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3264. Patrap
There are now 114 Days until the 2012 Winter Solstice
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3263. mfcmom
There are more than enough political blogs on the internet. Some of us are actually trying to follow the storm to protect our families. I would sincerely appreciate if you all take your political opinions elsewhere, if you need I can give you blog sites on WUmail. Jeesh.
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Wonder if this will pull dry air into its NW side now near landfall, lots of tropical systems seem to do that on a gulf landfall
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LSU Low Cloud Product
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Quick look at pacific storms

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3259. JasonRE
Well I guess this storm isn't as serious as I've been reading about. Our company in Lafayette has us open tomorrow for business. Am I losing my mind? I've been tracking this thing since it began and now I'm going to have to sit through this at work? It sure as hell doesn't seem to bother the owner enough.
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Wow, they might actually not upgrade Isaac to a hurricane. I'm interested to hear their reasoning to disregard the dropsonde data if so.
AL, 09, 2012082812, , BEST, 0, 278N, 882W, 60, 976, TS
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Quoting FelixTheKat:
isaac starting to look rather poor again.

dry air is once again destroying his little core lol. thank goodness he is such a pathetic little system.


Rather poor??? Pathetic little storm???
Isaac is still firing convection around the center and is producing very strong TS to hurricane force winds. Isaac will have a big storm surge and be dumping a lot of rain. Isaac is not a pathetic little storm.
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Quoting Patrap:
ENTERGY Louisiana just rang 300,000 Customers with the Following

Tropical Storm Force winds are expected for 30 hours and the yada, yada, yada, ..
Got a lot of rain in Fl with him as well as tornado so be prepared Gulf states!
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Quoting FelixTheKat:
isaac starting to look rather poor again.

dry air is once again destroying his little core lol. thank goodness he is such a pathetic little system.



Trolling?
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Quoting LargoFl:
is this rain going into the drought area's of georgia?
The rain has passed over some drought area in central GA. But one band isn't nearly enough. :\ It's misting just north of Atlanta Metro and winds are dead calm. I'm wondering what the rest of the day will bring since it seems there's only the one band and then no more rain bands. Isaac throwing some weight off and will spin up a bit before land fall?
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.