Little change to Isaac, but storm poses a serious storm surge threat

By: Dr. Jeff Masters , 3:25 PM GMT on August 27, 2012

Share this Blog
48
+

Tropical Storm Isaac has changed little in strength or organization this morning, as the storm heads northwest at 14 mph towards the Central Gulf Coast. There are two hurricane hunter aircraft in the storm, and Isaac's central pressure held steady at 989 mb at the 8:30 am and 9:15 am center fixes. Top surface winds remain near 65 mph. Infrared and visible satellite loops show that Isaac is a very large storm, but isn't very symmetric. Heavy thunderstorm activity is lacking on the southeast side, where 10 knots of wind shear is driving dry air into the circulation. The center is surrounded by a ring of echoes now, which was not the case on Sunday. However, the echoes are weak. The 8:30 am center report from the Hurricane Hunters reported about half of a ragged eyewall, but the 9:15 am report did not mention any evidence of an eyewall. Isaac will have to form an eyewall in order to intensify significantly.


Figure 1. Morning satellite image of Isaac. Note the lack of heavy thunderstorm activity on the storm's southeast side, where dry air and wind shear are combining to interfere with development.

Isaac's rains
Isaac's heaviest rains have fallen along a swath from the east coast of Florida near West Palm Beach to the center of the state, just south of Orlando. West Palm Beach received 7.57" of rain from Isaac as of 10 am EDT this morning. A trained spotter in Western Boynton Beach reported 10" of rain from midnight to midnight Sunday. Heavy rains from Isaac are lingering over Cuba but have ended in Haiti and the Dominican Republic; flash floods in Haiti from Isaac's torrential rains killed at least nineteen, and two died in the Dominican Republic.


Figure 2. Radar-estimated rainfall from Melbourne, Florida radar shows that Isaac has dumped a wide swath of 3+ inches of rain (orange colors) across the state.

Latest model runs for Isaac
The latest set of 0Z and 06Z (8 pm and 2 am EDT) model runs are fairly unified taking Isaac ashore near Southeast Louisiana late Tuesday night or early Wednesday morning, but continue to show major differences in what happens after that. It is still uncertain if a trough of low pressure passing to the north of Isaac will be able to turn the storm due north, as the ECMWF model is predicting, or bypass the storm, allowing a more west-northwest motion into western Louisiana, like the GFS model is predicting. In either case, Isaac is likely to slow down as it approaches the coast, which will increase the damage potential fro m its wind, storm surge, and rains. The latest 8-day precipitation forecast from the GFS model calls for 10 - 20 inches of rain over much of Louisiana. The ECMWF model predicts that these heavy rains will fall more over Mississippi. It appears likely that Arkansas will see some heavy rains from Isaac late in the week, which would help put a dent in the exceptional drought conditions there.


Figure 3. Predicted precipitation for the 8-day period from 2 am Monday August 27 to 2 am Tuesday September 4, from the 2 am EDT August 27 run of the GFS model. This model is predicting a wide swath of 5 - 10 inches of rain (orange colors) will affect portions of Louisiana. Additional very heavy rains are predicted for the Midwest, as moisture from Isaac interacts with a cold front. Image credit: NOAA/NCEP.

Intensity forecast for Isaac
Isaac is currently crossing over a relatively cool eddy of water, which will keep intensification slow today. By tonight, the total heat content of the waters increases, which should aid intensification. Low wind shear of 10 knots or less is likely until landfall. An analysis of upper level winds from the University of Wisconsin CIMSS shows that upper-level outflow to the north is not as strong as yesterday, which should also slow intensification today. The models forecast the upper-level outflow should improve by Tuesday. A storm this large will have trouble undergoing rapid intensification, and Isaac's most likely intensity at landfall will be as a Category 1 hurricane, which is what most of the intensity models are forecasting.


Figure 4. Track of Hurricane Gustav of 2008, which followed a path very similar to that of Isaac's predicted path.

Storm surge forecast for Isaac
Storm surge is the primary damage threat from Isaac. Isaac is a huge storm, with tropical storm-force winds that extend out 205 miles from the center. For comparison, Hurricane Katrina at landfall had tropical storm-force winds that extended out 230 miles from its center. Isaac's large size will enable it to set a large area of the ocean into motion, which will generate a large storm surge once the storm approaches land on the Gulf Coast. Water levels at Shell Beach, Louisiana, just east of New Orleans, were already elevated by 1' this morning. Conversely, water levels have fallen by 2' this morning at St. Petersburg, Florida, where strong offshore winds due to Isaac's counter-clockwise circulation have carried water away from the coast. The latest 6:30 am EDT Integrated Kinetic Energy analysis from NOAA's Hurricane Research Division put the destructive potential of Isaac's winds near 0.6 on a scale of 0 to 6, but the destructive potential of Isaacs's storm surge was 2.1 on a scale of 0 to 6. I expect this destructive potential will rise above 3 by time Isaac makes landfall, making Isaac's storm surge similar to that generated by Category 2 Hurricane Gustav of 2008, which followed a path very similar to Isaac's predicted path. Gustav brought a storm surge characteristic of a Category 1 hurricane to New Orleans: 9.5' to Lake Borgne on the east side of the city. A higher Category 2-scale surge occurred along the south-central coast of Louisiana, and was 12.5' high in Black Bay, forty miles southeast of New Orleans. Recent model runs indicate Isaac may slow down to a forward speed under 5 mph on Tuesday evening and Wednesday morning, close to the coast. If Isaac is just offshore at this time, the coasts of Southeast Louisiana, Mississippi, Alabama, and the Florida Panhandle will be exposed to a large storm surge with battering waves for two high tide cycles. This sort of extending pounding will be capable of delivering more damage than the storm surge of Hurricane Gustav of 2008.

The affect of storm size and angle of approach on storm surge
A 2008 paper by Irish et al., The influence of storm size on hurricane surge, found that large storms like Isaac are capable to delivering a 30% larger storm surge to the coast than a smaller storm with the same maximum wind speeds. The angle with which the storm hit the coast is important, too--a storm moving due north or slightly east of north will deliver a storm surge about 10% greater than a storm moving NNW or NW. Consult our Storm Surge pages for detailed information on what the risk is for the coast. I expect that Isaac's storm surge will be about 30% higher than the typical surge one would expect based on the maximum wind speeds.

Isaac's storm surge will provide the first test of the newly-completed New Orleans levee system upgrade. In the wake of the disastrous storm surge flooding from Hurricane Katrina in 2005, Congress appropriated $14.5 billion to upgrade the New Orleans levee system to withstand a Category 3 hurricane storm surge. Katrina was a Category 3 storm at landfall, but the storm passed far enough to the east of the city that its storm surge was characteristic of a Category 1 - 2 storm at the places where the city's flood walls and levees failed. The new flood defenses were only partially completed in time for the arrival of Hurricane Gustav in 2008, which hit Central Louisiana as a Category 2 storm. Gustav brought a storm surge characteristic of a Category 1 hurricane to New Orleans: 9.5' to Lake Borgne on the east side of the city. Since that time, the imposing 2-mile long IHNC Flood Barrier has been completed to block off the funnel-shaped pair of canals on the east side of the city. I expect New Orleans' new flood defenses will be able to hold back Isaac's surge, but areas outside the levees are at risk of heavy storm surge damage.


Figure 5. A portion of New Orleans' new $14.5 billion dollar flood defenses, as taken from an Army Corps of Engineers map.

New Orleans flood defense info
Army Corps of Engineers map of the new flood defenses
Army Corps of Engineers video showing the flood defenses
New York Times article, Vast Defenses Now Shielding New Orleans

Invest 97L off the coast of Africa
A tropical wave (Invest 97L) is located in the Middle Atlantic, about 1050 miles west-northwest of the Cape Verde Islands. The storm has a modest amount of spin and heavy thunderstorms, and is under moderate wind shear. In their 8 am EDT Tropical Weather Outlook, NHC gave 97L a 30% chance of developing by Wednesday morning. None of the reliable models foresee that 97L will be a threat to the Lesser Antilles Islands, and high wind shear should begin to tear the disturbance apart on Tuesday.

Another tropical wave that moved off the coast of Africa on Sunday is located just south of the Cape Verde Islands. This disturbance is moving west at 10 - 15 mph, and could arrive in the Lesser Antilles around September 2. Several models develop the disturbance into a tropical depression late this week, and NHC is giving the disturbance a 10% chance of becoming a tropical depression by Wednesday morning.

Angela Fritz will have a new post here by 6 pm EDT. I'm in Atlanta to help out The Weather Channel with their on-air hurricane coverage, and will doing a few 3-minute tropical updates at 30 minutes past the hour between 2:30 - 7:30 pm EDT today.

Jeff Masters

Tropical Storm Isaac (chelina)
View from the north side of the Sunshine Skyway Bridge.
Tropical Storm Isaac
our street at noon today (seflagamma)
Aug 26, 2012: Isaac floods our street really bad. Now nearly 11
our street at noon today

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 1259 - 1209

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36Blog Index

1259. Levi32
With 80kt winds showing up in the SW eyewall and the pressure falling quickly now, down to 982mb, Isaac looks like he is tightening his core and starting to isolate a bubble of moisture from the dry air in the NE quad. Once the core is insulated like this, the deepening really starts. This will be a hurricane at the 4pm CDT advisory.

Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
MH09 is impressed. A dropsonde released into Isaac's eye has brought back an MSLP of 982mb plus a 13mph surface wind, which would further reduce the pressure an additional millibar to 981mb. The splash location was 26.23N 85.94W. Isaac could potentially be undergoing rapid intensification.

000
UZNT13 KNHC 272002
XXAA 77208 99262 70859 08165 99982 27607 20511 00658 ///// /////
92534 24810 22015 85276 22248 23011 88999 77999
31313 09608 81936
61616 AF306 2709A ISAAC OB 11
62626 EYE SPL 2623N08594W 1938 MBL WND 21014 AEV 20802 DLM WND 21
514 982841 WL150 21012 083 REL 2622N08595W 193613 SPG 2622N08594W
193731 =
XXBB 77208 99262 70859 08165 00982 27607 11895 22802 22850 22248
21212 00982 20511 11931 22015 22911 21017 33871 21013 44856 23011
31313 09608 81936
61616 AF306 2709A ISAAC OB 11
62626 EYE SPL 2623N08594W 1938 MBL WND 21014 AEV 20802 DLM WND 21
514 982841 WL150 21012 083 REL 2622N08595W 193613 SPG 2622N08594W
193731 =
;


Well, if it's 981, that's a 3 mb drop in the last hour.
Member Since: July 15, 2006 Posts: 17 Comments: 10284
Wind readings are CLOSE to a hurricane, but it's clear the winds are catching up to the pressure. 982mb is roughly a 85mph storm usually, he isn't there yet.
Member Since: Posts: Comments:
1256. Dsntslp
The newest (layman and non expert)theory here in regards to our local flooding is that it is because there are so many cars in the ditches and canals stopping the water flow in culverts. A big crane has been seen moving into the area and it is thought that it will be used to remove vehicles from the waterways.
Member Since: Posts: Comments:
Anyone else notice this from the AF Recon ----Time: 19:54:30Z
Coordinates: 25.6N 86.65W
Acft. Static Air Press: 841.3 mb (~ 24.84 inHg)
Acft. Geopotential Hgt: 1,482 meters (~ 4,862 feet)
Extrap. Sfc. Press: -
D-value: -
Flt. Lvl. Wind (30s): From 287° at 69 knots (From the WNW at ~ 79.3 mph)
Air Temp: 17.4°C* (~ 63.3°F*)
Dew Pt: -*
Peak (10s) Flt. Lvl. Wind: 70 knots (~ 80.5 mph)
SFMR Peak (10s) Sfc. Wind: 48 knots (~ 55.2 mph)
SFMR Rain Rate: 7 mm/hr (~ 0.28 in/hr)
(*) Denotes suspect data
Member Since: August 21, 2011 Posts: 0 Comments: 143
1254. HadesGodWyvern (Mod)

Japan Meteorological Agency
Tropical Cyclone Advisory #79
TYPHOON TEMBIN (T1214)
3:00 AM JST August 28 2012
====================================

SUBJECT: Category Three Typhoon In Bashi Channel

At 18:00 PM UTC, Typhoon Tembin (975 hPa) located at 21.8N 121.0E has 10 minute sustained winds of 65 knots with gusts of 95 knots. The cyclone is reported as moving east northeast at 16 knots.

Dvorak Intensity: T4.0

Storm Force Winds
================
50 NM from the center

Gale Force Winds
=================
150 NM from the center in southeast quadrant
90 NM from the center in northwest quadrant

Forecast and Intensity
========================

24 HRS: 25.6N 123.2E - 65 knots (CAT 3/Strong Typhoon) Yaeyama Islands
48 HRS: 29.8N 123.0E - 55 knots (CAT 2/Severe Tropical Storm) East China Sea
72 HRS: 33.5N 122.9E - 55 knots (CAT 2/Severe Tropical Storm) Yellow Sea

Japan Meteorological Agency
Tropical Cyclone Advisory #63
TYPHOON BOLAVEN (T1215)
3:00 AM JST August 28 2012
====================================

SUBJECT: Category Three Typhoon In East China Sea

At 18:00 PM UTC, Typhoon Bolaven (960 hPa) located at 32.8N 125.4E has 10 minute sustained winds of 65 knots with gusts of 95 knots. The cyclone is reported as moving north at 15 knots.

Dvorak Intensity: T4.0

Storm Force Winds
==================
150 NM from the center in east quadrant
120 NM from the center in west quadrant

Gale Force Winds
==================
350 NM from the center in east quadrant
300 NM from the center in west quadrant

Forecast and Intensity
======================

24 HRS: 41.0N 126.1E - 55 knots (CAT 2/Severe Tropical Storm) Overland Korean Peninsula
48 HRS: 48.5N 132.7E - Extratropical Cyclone Near Amur River Basin
Member Since: Posts: Comments:
The 982mb drop was with 11 knot surface winds, so chances are the pressure is 981mb. This thing is really deepening.
Member Since: Posts: Comments:
Had the first day of school today, taking AP Calculus and AP Physics... should really help with my meteorology future :)
Member Since: Posts: Comments:
I see no gulp of dry air...but I see a moist environment.
Member Since: Posts: Comments:
Quoting TXHuRRicanE:
my eyes are telling me that its going more W-WNW but people saying its going NNE? which is it?

People in Texas see it going west, Florida people east.
Member Since: Posts: Comments:
Still not seeing much here in St Pete, occasional wind and rain. Nothing severe, I thought that east band would have reached over here by now, but it is just sitting there. I am sure they want it to move..
Member Since: Posts: Comments:
1248. flcanes
Quoting NICycloneChaser:
Level
982mb (29.00 inHg)

Here we go.

upgrade time
Member Since: Posts: Comments:
MH09 is impressed. A dropsonde released into Isaac's eye has brought back an MSLP of 982mb plus a 13mph surface wind, which would further reduce the pressure an additional millibar to 981mb. The splash location was 26.23N 85.94W. Isaac could potentially be undergoing rapid intensification.

000
UZNT13 KNHC 272002
XXAA 77208 99262 70859 08165 99982 27607 20511 00658 ///// /////
92534 24810 22015 85276 22248 23011 88999 77999
31313 09608 81936
61616 AF306 2709A ISAAC OB 11
62626 EYE SPL 2623N08594W 1938 MBL WND 21014 AEV 20802 DLM WND 21
514 982841 WL150 21012 083 REL 2622N08595W 193613 SPG 2622N08594W
193731 =
XXBB 77208 99262 70859 08165 00982 27607 11895 22802 22850 22248
21212 00982 20511 11931 22015 22911 21017 33871 21013 44856 23011
31313 09608 81936
61616 AF306 2709A ISAAC OB 11
62626 EYE SPL 2623N08594W 1938 MBL WND 21014 AEV 20802 DLM WND 21
514 982841 WL150 21012 083 REL 2622N08595W 193613 SPG 2622N08594W
193731 =
;
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1246. WxLogic
Quoting mobilebayal:



What shift would this be?


It would depend on the orientation the C CONUS high takes as well as the Bermuda High to the E, but any point on the gap is a possibility, but assuming Isaac slows down considerably to allow steering to take a different configuration.
Member Since: Posts: Comments:
Quoting MAweatherboy1:

No.

Seeing consistent hurricane force flight level winds, doesn't look like they're getting down to the surface too well though. Probably a 70-75mph storm.


But they issued the vortex data message when they were coming from the NNW. I looked through every barb and found those readings but they were rain contaminated.
Member Since: Posts: Comments:
Quoting Caner:


Neither...

Track is still NW. Rapid expansion of the convection on the Western side made it appear to jog west for a few.

Microwave scan still shows path as being NW:


Thanks Caner :)
Member Since: Posts: Comments:
The strong SAL that spread all that dry sinking air to the W Atlantic and lack of instability has really put a hurting on storms this hurricane season. It seems every storm in the W Atlantic can't consolidate and stack worth a crap. It's still too early...but starting to wonder if this season will be a bust with the amount of hurricanes expected.
Member Since: Posts: Comments:
Quoting LADobeLady:
I'd rather have it saying it will hit LA now, chances are it will move.  Better to be the target two weeks out, then 1 day out.  Oh wait we are the target 1 day out .



Chances are it will move ....is an understatement .... hopefully it will not form...
i would hate to live in N.O. and have a second storm ...in 2 weeks
Member Since: Posts: Comments:
1241. flcanes
Quoting Gorty:
Henry's tweet:

"Latest recon showed 74kt winds SW of the center so chances are they are going to upgrade Isaac to a hurricane at 5pm edt."

i agree
Member Since: Posts: Comments:
Level
982mb (29.00 inHg)

Here we go.
Member Since: Posts: Comments:
1239. sar2401
Quoting Bluestorm5:
Angela is thinking Category 1...


‏@WunderAngela

I'd say there's a 95% chance that NHC increases Isaac's intensity to cat 1 in the 5pm EDT update.


Man, I sure hope so. Isaac has supposed to have become a hurricane "in a day or two" for about five days now. :)
Member Since: Posts: Comments:
Quoting flcanes:

ms/al border


That's what I'm thinking. Perhaps even a bit farther.

Link

He seems to have a mind of his own.
Member Since: Posts: Comments:
1237. JasonRE
Quoting hurricanehanna:

Jason - are you in Lafayette or Lafayette Parish? I can try to find out for you where to get the sandbags.


I am in Lafayette....about 10-12 minutes from Acadiana Mall. Thanks!
Member Since: Posts: Comments:
1236. Dakster
Quoting DelawareJack:
The Chicken Little of All Chicken Littles .. the Weather Channel has done it yet again .. scared people half to death for their own selfish wishes for ratings >> " Tampa was considered a possible landfall spot for Tropical Storm Isaac. The storm stayed well west of the city, bound apparently for Louisiana or Mississippi, and sunshine was drenching Tampa by Monday afternoon. " All this does is make things worse the next time there is a genuine threat .. people have already begun to see the " Hollywood -Like Antics " of the Weather Channel . and because of that some folks will not believe them the next time ..


Not that I could accuse News stations of down playing events -- BUT this is a damned if you do, damned if you don't scenario... So let's say the media says Tampa will be fine --- and Isaac strengthened and went further east as the models originally predicted. Tons of people show up, no one prepares and you have huge loss of life. What would your post look like then?

If you CHOOSE to never prepare after being shown what could be coming your way - that is your choice. However, I would rather prepare for what never happens, than not prepare for what does happen.

Just saying... Easy to Monday morning quarterback.
Member Since: Posts: Comments:
The stronger winds are located on the SW side due to dry air on the eastern side limiting thunderstorm growth there. The strongest convection on the west and southwest side has had to wrap around into the center this afternoon. This process is slower for intensification initially, but this could shield Isaac from further dry air entrainment up until landfall. Isaac might be able to strengthen quickly now.
Member Since: July 15, 2006 Posts: 17 Comments: 10284
Some mojo being blown around out there

Member Since: July 14, 2008 Posts: 1 Comments: 9630
1233. CJ5
Quoting kctinney:


For the lay person as myself, what does that exactly mean? TIA :)


That the southern part of the storm is much worse than the northern part.
Member Since: Posts: Comments:
1232. flcanes
Quoting GetReal:
It appears to me that Isaac has slowed down significantly this afternoon.

very much true
Member Since: Posts: Comments:
1231. Gorty
Henry's tweet:

"Latest recon showed 74kt winds SW of the center so chances are they are going to upgrade Isaac to a hurricane at 5pm edt."
Member Since: Posts: Comments:
Quoting tropicfreak:


But wasn't that 73.6 mph reading contaminated?

No.

Seeing consistent hurricane force flight level winds, doesn't look like they're getting down to the surface too well though. Probably a 70-75mph storm.
Member Since: Posts: Comments:
Quoting MAweatherboy1:
Its very borderline whether Isaac is a hurricane. Winds are probably right on the border. But the NHC should definitely call it one... Hopefully people will take it a little more seriously if it is declared a hurricane.



Funny how it has to be called a hurricane to care. I have been in tropical storms that actually did more damage than a hurricane. Many tropical storms have much more rain and more flooding. It all just depends.. People need to prepare in a TS as much as a Cat 1 cane , in my opinion.
Member Since: Posts: Comments:
Quoting WxLogic:
Gulp of dry air disrupting circulation:




Gulp of dry air? Nope, not even close.



That's about as much moisture as the atmosphere can possibly hold completely surrounding the center of Isaac and beyond. I've said this a million times but, I just want people to understand it because popular belief in these blogs is just to blame a lack of organization on dry air. Tropical cyclones can struggle with structure issues. When you're seeing a lack of convection it's because there isn't lift occurring in those regions which mean Isaac continues to struggle with balancing not only it's inner core but the whole structure.
Member Since: Posts: Comments:
1227. bwi
982mb at Splash Location: 26.23N 85.94W
Member Since: September 4, 2007 Posts: 0 Comments: 1385
1226. flcanes
Quoting kctinney:


For the lay person as myself, what does that exactly mean? TIA :)

nothing, really
Member Since: Posts: Comments:
1225. GetReal
It appears to me that Isaac has slowed down significantly this afternoon.
Member Since: Posts: Comments:
1223. FL1980
Quoting DelawareJack:
The Chicken Little of All Chicken Littles .. the Weather Channel has done it yet again .. scared people half to death for their own selfish wishes for ratings >> " Tampa was considered a possible landfall spot for Tropical Storm Isaac. The storm stayed well west of the city, bound apparently for Louisiana or Mississippi, and sunshine was drenching Tampa by Monday afternoon. " All this does is make things worse the next time there is a genuine threat .. people have already begun to see the " Hollywood -Like Antics " of the Weather Channel . and because of that some folks will not believe them the next time ..


I couldn't agree more!!!
Member Since: Posts: Comments:
Basically stalled out of the past hour or so.
Member Since: Posts: Comments:
1221. Caner
Quoting TXHuRRicanE:
my eyes are telling me that its going more W-WNW but people saying its going NNE? which is it?


Neither...

Track is still NW. Rapid expansion of the convection on the Western side made it appear to jog west for a few.

Microwave scan still shows path as being NW:

Member Since: Posts: Comments:
Quoting JasonRE:


Wish I could, but stuck at work. We are open tomorrow too. How nice! Can't wait to try and find sand bags at the last minute and put them out in the pouring rain!

Jason - are you in Lafayette or Lafayette Parish? I can try to find out for you where to get the sandbags.
Member Since: Posts: Comments:
Issac is ingesting some dry air through his NE quadrant on the vis loops......Not sure how much this will affect the jump to cane status (the 5-10 mph difference) in the short term.
Member Since: Posts: Comments:
1218. WxLogic
Quoting GetReal:
SAY WHAT????






UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 27 AUG 2012 Time : 184500 UTC
Lat : 26:30:36 N Lon : 85:56:18 W


CI# /Pressure/ Vmax
3.4 / 985.8mb/ 53.0kt


Final T# Adj T# Raw T#
2.9 3.4 3.4

Center Temp : -69.7C Cloud Region Temp : -59.0C

Scene Type : IRREGULAR CDO*

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : ON
Rapid Dissipation Flag : FLAG


C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 147km
- Environmental MSLP : 1009mb

Satellite Viewing Angle : 33.2 degrees


This is why I mentioned that any premature collapse in the convection near the center would disrupt it... unfortunately you can see it taking a nice chunk of dry air before is started having spasms.
Member Since: Posts: Comments:
1217. CJ5
The East coast of Florida may have been better off if Isaac would have taken that route. They are getting pounded with the rain and it still has plenty to go. My Bro in Sewell's Point said he has not seen it this bad in a long time.
Member Since: Posts: Comments:
Quoting Bluestorm5:
If I'm not mistaken, that's typical of West Pacific Typhoons, right?
Typical of southern hemisphere cyclone that typically have the strongest winds in the *southwestern quadrant.

Quoting TropicalAnalystwx13:
Isaac should be declared a hurricane at 5pm EDT.
A combination of flight-level data with the 20% reduction as well as SFMR data would lead to a 70-74mph cyclone. All up to the NHC at this point.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
If its a Hurricane at 5 then Pasch was still off...he thought it would be a hurricane by tuesday morning!
Member Since: Posts: Comments:
Quoting MAweatherboy1:

73.6mph surface winds would round to 74 which means Isaac is a hurricane... Am I right?


But wasn't that 73.6 mph reading contaminated?
Member Since: Posts: Comments:
12Z GFS Link
Member Since: Posts: Comments:
Quoting Tazmanian:




i would re move that wounder blog admin was this on here
It's gone already... did Press really just posted that? Wow, I am not sure if that was real Press because he's not that stupid...
Member Since: Posts: Comments:
1211. flcanes
Quoting Redbull77:


I am in Lafayette also. we stocked up yesterday as i had a kidney transplant in june, so i had to make sure i have all my meds and plenty to drink. I was actually supposed to go to N.O today for a dr. appt but i called and said i couldn't make it because i didn't want to get caught in that traffic coming back.I have noticed today the gas stations on the south side are running out of gas so at least some people are getting ready.

good for you
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Isaac's southern quadrant(s) are nearly twice as intense as the northern quadrant(s). It isn't everyday that you see such an occurrence with a northern hemispheric cyclone.


For the lay person as myself, what does that exactly mean? TIA :)
Member Since: Posts: Comments:
Member Since: Posts: Comments:

Viewing: 1259 - 1209

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.