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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Is this western movement just a jog in the last two frames or a trend
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By all information from recon Isaac is moving WNW....Dont understand why they said NW. They are the professional so we just have to take their word.
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2402. GetReal
Isaac has managed to get into the record books as the first ever 977MB TS.... He is literally a CAT 2 TS....
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Quoting Carnoustie:
BBC reports its now a Hurricane.


oops changed their mind,back to a TS,lol.
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Quoting StormThug:
They found flight level winds around 90mph I don't see how this isn't a hurricane

I don't know. I think it's a half-a-cane, at best.
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Good morning,

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They found flight level winds around 90mph I don't see how this isn't a hurricane
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2397. GetReal



No surprises here!
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BBC reports its now a Hurricane.
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still 70mph...

4:00 AM CDT Tue Aug 28
Location: 27.5°N 88.1°W
Moving: NW at 12 mph
Min pressure: 977 mb
Max sustained: 70 mph
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mississippi coast here. very cool night outside. the first light rain and the clouds rotating hard. bout damn time, feel like ive been watching isaac half my life. my family is thankful our area wont see another nightmare.7 years ago to the day i woke up and checked the radar, then went to tell my wife (then girlfriend) it wasnt too late to leave. we typically dont go. she said she was still ok with staying and i said " you know we could die, right"? we stayed and didnt die. good luck to all, keep ur heads down.
Member Since: June 28, 2009 Posts: 0 Comments: 79
2393. GetReal



Moonlightcowboy had predicted that Isaac may turn west at this point and slowdown near this latitiude. He also said this track would tale Isaac over the warmest waters of the Gulf loop, providing Isaac with the best oppurtunity at strengthening.... Let's see if he is going to be right about a landfall in south of Layfayette, La.
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Quoting sar2401:


Whoops, missed this before. The storms are being manipulated? By who? Do you have some actual evidenc eof this or just from reading chemtrail sites? I wouldn't consider you a troll but a quack may be a possibility. It seems more likely your tinfoil hat has gotten out of adjustment again
While I would tend to agree with you, silver iodide cloud seeding used to disrupt an eyewall is hardly as looney as chemtrails. I'm not saying that's what happened here, but that you should perhaps read up on weather modification before chastising the guy.
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Quoting sar2401:


Now that is funny. Thanks for the laugh.

:=)
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2390. GetReal
Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 28th day of the month at 07:57Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 309)
Storm Number & Year: 09L in 2012
Storm Name: Isaac (flight in the North Atlantic basin)
Mission Number: 29
Observation Number: 18
A. Time of Center Fix: 28th day of the month at 7:26:10Z
B. Center Fix Coordinates: 27°19'N 87°59'W (27.3167N 87.9833W)
B. Center Fix Location: 221 miles (355 km) to the SSW (192°) from Pensacola, FL, USA.
C. Minimum Height at Standard Level: 1,234m (4,049ft) at 850mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 52kts (~ 59.8mph)
E. Location of the Estimated Maximum Surface Wind: 12 nautical miles (14 statute miles) to the W (262°) of center fix
F. Maximum Flight Level Wind Inbound: From 3° at 57kts (From the N at ~ 65.6mph)
G. Location of Maximum Flight Level Wind Inbound: 22 nautical miles (25 statute miles) to the W (265°) of center fix
H. Minimum Sea Level Pressure: 977mb (28.85 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 16°C (61°F) at a pressure alt. of 1,528m (5,013ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 22°C (72°F) at a pressure alt. of 1,526m (5,007ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 19°C (66°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Open from the southwest to the northeast
M. Eye Shape & Diameter: Circular with a diameter of 26 nautical miles (30 statute miles)
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Levels (sfc and flt lvl centers are within 5nm of each other): Surface and 850mb
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 1 nautical mile
Remarks Section - Remarks That Were Decoded...
Maximum Wind Outbound: 78kts (~ 89.8mph) in the east quadrant at 7:52:00Z
Maximum Flight Level Wind: 78kts (~ 89.8mph) in the east quadrant at 7:52:00Z
Remarks Section - Additional Remarks...
MAX OUTBOUND SFMR SURFACE WIND 54 KT E QUAD 07:44:30Z


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2389. sar2401
OK, gang, I swore I wasn't going to stay up to watch the 5am update again tonight. If I don't go to bed now, it's going to sneak up on me. Keep watch and start posting in ALL CAPS with lots of exclamation points if rapid intensification sets in while I'm in the arms of Morpheus. See y'all later.
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Despite appearance, ISAAC is still strengthening. The pressure continues to drop, yet the winds remain the same. I believe its time to patent the term SI (slow intensification) that was mentioned earlier in the blog for this type of situation.

Appropriately used in a sentence such as:

OMG, the storm is undergoing SI!! (Exciting yet mild)
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2387. LargoFl
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2386. sar2401
Quoting lopaka001:
A moment of silence please!



Now that is funny. Thanks for the laugh.
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2385. LargoFl
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2384. LargoFl
Good morning folks!.here's the tampa bay area 7-day, we still have some of the effects of issac lingering with us today, supposedly nothing like yesterday, storms moving towards the northern gulf coast..have a safe day.....
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A moment of silence please!

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2382. sar2401
Quoting uncwhurricane85:


yeah im ready for him to be over so we can track a real storm!


Better get used to it. These ghastly storms are being caused by global warming...or cooling...or cloud seeding...or HAARP. This is the new normal. Regular, normally sane people, up at 0830 UTC watching really crummy looking storms do nothing for days and weeks on end. The fun times ended in 2005. :)
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this is one of the weirdest storms i've ever seen no doubt
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2380. sar2401
Quoting HurricaneHunterJoe:
Im gonna call it a night and go snuggle up to to my wifes booty................so carry on and hold down the fort.

Buenos Noches


Sure, Joe, rub it in for us single guys. :) Have a good morning.
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Quoting sar2401:

http://classic.wunderground.com/tropical/tracking /at201209_sat.html#a_topad. He's looking pretty ghastly right now.


yeah im ready for him to be over so we can track a real storm!
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2378. sar2401
Quoting uncwhurricane85:
does anyone have the latest satellite image of weak isaac!?

http://classic.wunderground.com/tropical/tracking /at201209_sat.html#a_topad. He's looking pretty ghastly right now.
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2377. sar2401
Quoting tomas5tex:
West trend......


Man, I sure wish I knew what that little tiny picture was supposed to show. I'll bet it's interesting. :)
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does anyone have the latest satellite image of weak isaac!?
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2375. sar2401
Quoting GBguy88:
On Pensacola Beach, between Portofino and Navarre, there are several areas where the waves are rolling up to the side of the road already. Wasn't expecting that.


High tide, full moon in three days, and some modest storm surge, I suspect. Compared to three days ago, not too bad. Do you have your official Weather Channel™ approved safety googles on while observing these waves? Can't be too careful with these monster storms, you know. :)
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West trend......
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2373. sar2401
Quoting jake436:
I figure you're kidding about hitting the Yuc, but not so much about the "south of west" movement. If you are serious about the "south of west" movement, you're watching the blob, and not the center of circulation. That's easy to do, considering the COC is ill defined. But that little blob, that's not the center (anymore). It's LEAVING the center. It's done that every time it's tried to ramp up and build convection overthe at the COC.


Yeah, I'm kidding, Jake. We just haven't had any Bold panic posts with lots of exclamation points lately since Isaac has turned into a steaming hot mess...again. I thought I'd just wake a few folks up. It does still appear to be moving west though. I'll be interested to see what track changes come up tomorrow...well, today, actually. :)
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2372. GBguy88
On Pensacola Beach, between Portofino and Navarre, there are several areas where the waves are rolling up to the side of the road already. Wasn't expecting that.
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Quoting sar2401:

Is this two foot rise significant, like in terms of a storm surge that's going to cause damage, or just a data point? Since I know nothing about the Delta, I can't tell.

The green line represents the storm surge.
The blue line is basically your predicted high and low tides.
The red line is the observed water levels.
Interesting about those charts is the winds are out of the north and the water is still rising.
You can check all the data points on this map:
ODIN
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2370. jake436
Quoting sar2401:

Is this two foot rise significant, like in terms of a storm surge that's going to cause damage, or just a data point? Since I know nothing about the Delta, I can't tell.
The bigger question is, where are the "outer banks" of LA??

A two foot rise isn't going to cause damage. The point is, it's ALREADY risen two feet. It takes 20' to top the levees around NOLA. But there are populated areas outside the levees that will flood, yes. Not from two feet, but from the 6'-12' forecast storm surge. A typical high tide is about 2' above 'normal', and during strong east winds in the spring time, it's quite common for 3'-4' of "surge" if the easterlies are persistant enough. But this will be more than that. You also have to factor in whenever normal high tide is, as that will only add to the equation.
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2369. sar2401
Quoting OBXNCWEATHER:


Lol. The first time, I let it slide. The second time he felt the need to show me where the gulf coast was I literally spoke to the tv and said "are you freaking kidding me?"

Speaking to your TV while watching The Weather Channel™ is a sign that the absoption process has begun. You'll soon be involutarily getting out your credit card and ordering arthritis cream and official Weather Channel™ beach safety goggles. I suggest you turn it off right away before things get worse. :)
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Im gonna call it a night and go snuggle up to to my wifes booty................so carry on and hold down the fort.

Buenos Noches
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2367. jake436
Quoting sar2401:
On the last few frames of the IR, in addition to looking like my ex-wife with the forked tail, Isaac appears to be moving south of west. OMG, this thing could hit the Yucatan!!!!!!!!!!!
I figure you're kidding about hitting the Yuc, but not so much about the "south of west" movement. If you are serious about the "south of west" movement, you're watching the blob, and not the center of circulation. That's easy to do, considering the COC is ill defined. But that little blob, that's not the center (anymore). It's LEAVING the center. It's done that every time it's tried to ramp up and build convection overthe at the COC.
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2366. sar2401
Quoting lopaka001:
Water levels rose almost 2 feet in the outer banks of LA.




Is this two foot rise significant, like in terms of a storm surge that's going to cause damage, or just a data point? Since I know nothing about the Delta, I can't tell.
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Quoting CoastalAlabama:
Another laugh about TWC throughout the day:

Along with my newfound knowledge of skin tags, I have been reminded about 28 times that the picture I am looking at on the screen shows the N. Gulf land mass and the Florida peninsula...with white squiggly lines to augment and highlight the need to show me where the northern gulf states are and where Florida is.

And that Obama 'approved' the emergency requests for Louisiana.

I needed to know that, of course.


Lol. The first time, I let it slide. The second time he felt the need to show me where the gulf coast was I literally spoke to the tv and said "are you freaking kidding me?"
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2364. sar2401
On the last few frames of the IR, in addition to looking like my ex-wife with the forked tail, Isaac appears to be moving south of west. OMG, this thing could hit the Yucatan!!!!!!!!!!!
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Water levels rose almost 2 feet in the outer banks of LA.



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isaac going to mexico for tacos......in a western beeline
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2361. sar2401
Quoting Bamawatcher:
Wonder what the odds are it continues to slide west with any descent impact on galveston there are probably about 100-150 boats here at anchor just outside the jettys...


I think he is moving west but he'd have to move west a lot to have any impact on Galveston. In terms of odds, I think you have better odds at keno at an indian casino. :)
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Quoting leftlink:


The reason there are no high winds is that there is no tight pressure gradient. From the recon images posted by Levi, 100 miles from the storm the pressure is around 999 and going down steadly to 995, then 990, then 988, with 55mph winds all the way in. When you get closest to the center the winds actually are decreasing because the loose eye is 44 miles in diameter, according to the hurricane hunters. The pressure is then decreasing more rapidly to 982, but the 6mb drop is not enough to support a hurricane-force eye.

If the system continues west and bumps into the high pressure ridge in Texas the pressure gradient could get steep on the west side even if the storm does not strengthen much. Resulting in high winds on what is usually the weaker (west) side of the hurricane.


Finally the real data came in. Pressure decreased to 985 before the winds started to decrease, and the final pressure at flight level was 977.4. Here is the center fix, same as reported a few posts above:

072630 2719N 08757W 8429 01304 9774 +211 +209 178007 009 020 003 00
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did tom leave?
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Wonder what the odds are it continues to slide west with any descent impact on galveston there are probably about 100-150 boats here at anchor just outside the jettys...
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2357. sar2401
Quoting franckinator:
These storms are being manipulated...for seven years it has been the case. Anyone who suggests it is considered a quack or a troll or such. Either the storms are being manipulated, or present-day weather scientists are morons. Look at the forecasts for this storm, and what actually happened.


Whoops, missed this before. The storms are being manipulated? By who? Do you have some actual evidenc eof this or just from reading chemtrail sites? I wouldn't consider you a troll but a quack may be a possibility. It seems more likely your tinfoil hat has gotten out of adjustment again
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Quoting CoastalAlabama:


Concur on all fronts.

I think Tacky Jacks is staying open as long as it makes sense for them...??

Closing the old tunnel in the a.m...

Will get some rising water, Felix's et al are up high enough on stilts that they'll be fine...downtown will get alot of rain, likely...if anything like Miami on Monday. Ugh.



lol...wonder if veet's is open?
Member Since: September 3, 2009 Posts: 0 Comments: 495
Quoting HurricaneHunterJoe:
The last I saw Kirk, he was just northwest of Puerto Rico heading wnw or nw.



tell spock not me cuz the doc was looking for him....lol
Member Since: September 3, 2009 Posts: 0 Comments: 495
Quoting tomas5tex:
This and the last 2 fixes has shown a west trend. Maybe a wobble...then again maybe something else. Also pressure is down again since last fix.


me: 07:26:00Z
Coordinates: 27.3167N 87.9833W
Acft. Static Air Press: 843.9 mb (~ 24.92 inHg)
Acft. Geopotential Hgt: 1,302 meters (~ 4,272 feet)
Extrap. Sfc. Press: 977.8 mb (~ 28.87 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 4° at 2 knots (From the N at ~ 2.3 mph)
Air Temp: 21.1°C (~ 70.0°F)
Dew Pt: 20.4°C (~ 68.7°F)
Peak (10s) Flt. Lvl. Wind: 5 knots (~ 5.8 mph)
SFMR Peak (10s) Sfc. Wind: 20 knots* (~ 23.0 mph*)
SFMR Rain Rate: 2 mm/hr* (~ 0.08 in/hr*)


Maybe Isaac running from the dry air to his northeast?
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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.

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