Threat to New Orleans grows

By: Dr. Jeff Masters , 9:36 PM GMT on August 26, 2005

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Latest compter model runs have shifted significantly west in the past six hours, and the threat of a strike on New Orleans by Katrina as a major hurricane has grown. The official NHC forecast is now 170 miles west of where it was at 11am, and still is to the east of the consensus model guidance. It would be no surprise if later advisories shift the forecast track even further west and put Katrina over New Orleans. Until Katrina makes its northward turn, I would cast a very doubtful eye on the model predictions of Katrina's track. So much for the model prediction being high confidence, as I was surmising at 8am this morning! Recurvature is a difficult situation to forecast correctly.

The pressure of Katrina has continued to slowly drop, to 965mb. Dry air on the northwest side of the hurricane has interfered with the strengthening process, and may continue to do so over the next day. I still expect Katrina to attain Category 3 status Saturday, but Category 4 is looking less likely due to the dry air to the north. As one can see from the latest long range radar out of Key West, the northwest side of the eyewall is fragmented.

Some fairly prodigious rain amounts fell in the Miami area today. Homestead south of Miami measured 13.2 inches, and isolated amounts of 15 - 20 inches were observed between Homestead and Miami. The 7.55 inches at Key West was its 10th heaviest rainy day in history.

Jeff Masters

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1193. spacecoastgirl
9:26 PM GMT on August 28, 2005
YIKES!
1192. MSY68
2:59 PM GMT on August 27, 2005
CAT 5 direct hit for NO....say good bye to NO forever if that happens
1191. MSY68
2:58 PM GMT on August 27, 2005
wind is now forecast for 140 mph at landfall with cat 5 still a possibility
1190. MSY68
2:57 PM GMT on August 27, 2005
Pressures at 940MB...10am advisory is finally out
1189. MSY68
2:55 PM GMT on August 27, 2005
LaFleur...i know..i checked and flight are all sold out...no seats available
1188. LaFleur
2:49 PM GMT on August 27, 2005
MSY68 I'm in the SAME boat. My big problem is trying to decide WHERE to go. If you don't have a reservation, you're out of luck. Closest rooms are Dallas and Memphis.
1187. MSY68
2:17 PM GMT on August 27, 2005
ANY THOUGHTS HERE on whether this will miss NO and hit further east...im in NO and am still trying to decide whther to stay
1186. leftyy420
1:59 PM GMT on August 27, 2005
well she is in the midest of a eye wall replcement, she has grown is size. i expect her to satrt rapidly stregthening again in 3 hrs
Member Since: August 24, 2005 Posts: 35 Comments: 1987
1185. WeatherSpotter
12:16 PM GMT on August 27, 2005
None the less even if it does hit Biloxi - its still going to get NO hard with the rain and storm surge. It will be interesting to see what happens today and tonight with the hurricane.
1184. gbundersea
11:57 AM GMT on August 27, 2005
The latest GFDL and GFS models have swung eastward to the Biloxi-Pascagoula, MS area.

Hmmm...
1183. stmarylalady
11:52 AM GMT on August 27, 2005
yep, nothing new, my shift is over, gonna try to catch some zzzs if I can, after a trip to the store. Will be reading you guys' posts this afternoon.
1182. wxgssr
11:51 AM GMT on August 27, 2005
breakfast and woodworking...will check back later.
1181. WeatherSpotter
11:48 AM GMT on August 27, 2005
No change from the 5am advisory - I'm outta here for the day - will be back tonight - Have a great day everyone.
1180. Weareallgunnadie
11:48 AM GMT on August 27, 2005
nothing new on the 8AM advisory
1179. wxgssr
11:41 AM GMT on August 27, 2005
Yeah, then I need to start sawing away...
They may or may not get a DS in time for the 0800 update, I was just pointing out that it was an extrapolated SLP.
1178. WeatherSpotter
11:40 AM GMT on August 27, 2005
wxgssr, are you going to stick around the forum for the 8 am advisory?
1177. bayoubamaboy
11:40 AM GMT on August 27, 2005
Traffic is light in NOLA. http://www.dotd.state.la.us/press/traffic_cameras/cameras_no.asp?camera=Cam4
It will not be pretty when evac orders are issued.
1176. wxgssr
11:37 AM GMT on August 27, 2005
"WV indicates a sw trof in TX pandle is begging t oerode teh ridge a bit...first evidence I have seen of the forecasted erosion. One it makes it over the ridge axis, it will begin to move se toweards teh GUlf caost...opening the predicted "soft spot" for Katrina ot traveres through."

Let me clean that up..like I should have before I hit send, DOH!

WV indicates a s/w trof in TX panhandle is beggining to erode the ridge a bit...first evidence I have seen of the forecasted erosion. Once it makes it over the ridge axis, it will begin to move SE towards the Gulf coast...opening the predicted "soft spot" for Katrina to traverse through.


1175. WeatherSpotter
11:36 AM GMT on August 27, 2005
We'll see in 25 minutes are you going to stay round for the 8:00 advisory
1174. wxgssr
11:33 AM GMT on August 27, 2005
Weatehr Spotter, the 942 mb is extrapolated from FL...it may be deeper or higher when they get a dropsonde reading.
1173. wxgssr
11:30 AM GMT on August 27, 2005
WOW 12 degree C thermal spread. Cue the "shark is approaching" music from Jaws...lol
1172. wxgssr
11:28 AM GMT on August 27, 2005
WV indicates a sw trof in TX pandle is begging t oerode teh ridge a bit...first evidence I have seen of the forecasted erosion. One it makes it over the ridge axis, it will begin to move se toweards teh GUlf caost...opening the predicted "soft spot" for Katrina ot traveres through.

Big day of cutting plywood ahead of me...already have it here just need to shape it to the windows. Needed to get done anyway, and nothing like mama nature's cattle prod to help "get er done..."

Said this before, but NHC really wasted their 11:00 am opportunity yesterday, IMO. They could have "walked west" at 11:00 and 5:00 instead of making the "giant leap" at 5:00 yesterday pm. Watch, Max Mayfield will answer this by saying NOLA was in the 72 hour cone at 11:00 yesterday morning...which they were...but instead of being on the extreme left flank, and having a Govt Official prodding move closer to centerline of the track would have been a better solution. Some of us saw all the same stuff they did before the 11:00 was issued. In their defense, it could be argued that they were still concerned about a right hook close to the Fl west coast both meteorologically and politically.
Empirical evidence was NOT supporting that hook though...the SW dive and the real world environmental analysis did not support it at all. I remember posting on this blog somewhere wondering what I was missing to keep them so far right. Apparently, nothing.
Now, the entire SE LA governmental decision makers are behind the curve. They need to order an evacuation RIGHT NOW...if they have a hope of getting people outta there before conditions deteriorate to the point that further movement is not an option on Monday.
1171. WeatherSpotter
11:25 AM GMT on August 27, 2005
Millibars have seemed to level out at 940 - 942 MB's at this time
1170. WeatherSpotter
11:25 AM GMT on August 27, 2005
000
URNT12 KNHC 271119
VORTEX DATA MESSAGE
A. 27/11:07:50Z
B. 24 deg 23 min N
084 deg 32 min W
C. 700 mb 2594 m
D. NA kt
E. deg nm
F. 158 deg 085 kt
G. 053 deg 031 nm
H. EXTRAP 942 mb
I. 8 C/ 3042 m
J. 20 C/ 3046 m
K. 13 C/ NA
L. CLOSED WALL
M. C9
N. 12345/ 7
O. 0.03 / 2 nm
P. AF304 1212A KATRINA OB 29
MAX FL WIND 106 KT SE QUAD 09:34:20 Z
MAX FL TEMP 23 C, 52 / 7NM
SLP EXTRAP FROM 700 MB
PRELIMINARY!
1169. WeatherSpotter
11:05 AM GMT on August 27, 2005
Yea she seems off in my opinion - I'm surprised they even keep her cause she's a disguist watching her in the mornings.
1168. kerigangirl
11:04 AM GMT on August 27, 2005
Hey WeatherSpotter - ditto on the Hillary Andrews post. Not a fan of WC in the morning. Trying to get too "cute" or something. Wish they would go back to being more technical. Used to offer a lot more detail and just some plain old weather maps instead of all the graphics. If I wanted that I could watch the other morning shows.

1167. kerigangirl
10:55 AM GMT on August 27, 2005
Where's StormTop? Have to say he called it right Friday morning. Ridge doesn't seem to be breaking down.
:( dissapointed kerigangirl in columbia, sc - sure hoping it would come this way and keep temps down all week.
1166. MaryEstherFLA
10:47 AM GMT on August 27, 2005
well, would of been nihs class of 66, except we moved to Baton Rouge just in time for Betsy!
Member Since: August 4, 2005 Posts: 26 Comments: 1190
1165. stmarylalady
10:46 AM GMT on August 27, 2005
nish....class of 84
1164. MaryEstherFLA
10:42 AM GMT on August 27, 2005
yes, I wanted to let you know I knew what it's like to be on "an island in the swamp" in an older house. Lydia was on the way to almost everywhere for us. I went to highschool in New Iberia.
Member Since: August 4, 2005 Posts: 26 Comments: 1190
1163. stmarylalady
10:39 AM GMT on August 27, 2005
omg...you grew up on weeks island?...how cool.....i live in st mary parish now but grew up in new iberia...my mom's family is from coteau and my dads is from lydia.

isn't it funny how so many of those old houses hold up so well.
1162. MaryEstherFLA
10:38 AM GMT on August 27, 2005
sorry to get you all off topic...just be safe and prepared...from northwest Florida
:-)
Member Since: August 4, 2005 Posts: 26 Comments: 1190
1161. WeatherSpotter
10:33 AM GMT on August 27, 2005
LSUGIRL are you still there?
1160. MaryEstherFLA
10:33 AM GMT on August 27, 2005
Town?!...Weeks Island...it was a company village then, but high elevation. I was a teenager but remember the sound of "locomotives" in the woods. We were in a small frame house, but didn't have damage to us.
Member Since: August 4, 2005 Posts: 26 Comments: 1190
1159. stmarylalady
10:29 AM GMT on August 27, 2005
LOL MaryEsther, yes, that sounds like a familiar saying.

Our house has been around over a 100 yrs so I am kinda hoping it can weather one more storm if need be.

You sure were in our neighborhood. Hilda was a couple of years before me but I use to hear stories from my mom and grandma about her. What town were you living in back then?
1158. MaryEstherFLA
10:18 AM GMT on August 27, 2005
stmarylalady...my dad says "run from the water...hide from the wind" I grew up in your neighborhood and we went through Hurricane Hilda in the '60's. He said the eye was about 4 miles from us.
Member Since: August 4, 2005 Posts: 26 Comments: 1190
1157. nola
10:18 AM GMT on August 27, 2005
Dragoon - please explain significance of "thermal gradient"... What does that mean?
1156. WeatherSpotter
10:16 AM GMT on August 27, 2005
Yea I've asked her to come north - I'm in Kentucky we've been together for 1 year and we see each other about a week every 2 to 3 months once things get straighten out one of us is going to move. LOL
1155. lsugirl
10:14 AM GMT on August 27, 2005
Hello WeatherSpotter,

I'm not even going to try to leave BR at this point. I've seen how bad I-10 gets when the evacs start. I do not want to be caught in that chaos! I figure I will ride it out, or find a shelter if the worst scenario occurs,
1154. Dragoon
10:12 AM GMT on August 27, 2005
The only thing that doesn't seem so healthy about Katrina is the fact that the thermal gradient is only 2 degrees C

For a storm of this pressure and strength it should be closer to 9 or 10 degrees
1153. Dragoon
10:11 AM GMT on August 27, 2005
000
URNT12 KNHC 270953
VORTEX DATA MESSAGE
A. 27/09:32:40Z
B. 24 deg 22 min N
084 deg 22 min W
C. 700 mb 2591 m
D. NA kt
E. deg nm
F. 045 deg 090 kt
G. 316 deg 010 nm
H. 940 mb
I. 17 C/ 3045 m
J. 19 C/ 3049 m
K. 10 C/ NA
L. CLOSED WALL
M. C10
N. 12345/ 7
O. 0.02 / 1 nm
P. AF304 1212A KATRINA OB 23
MAX FL WIND 104 KT NE QUAD 07:08:10 Z
SMALL HAIL SE EYEWALL.
1152. Dragoon
10:10 AM GMT on August 27, 2005
940 mb is on the nhc site.
1151. WeatherSpotter
10:08 AM GMT on August 27, 2005
Hey LSUGirl,

My GF works as a PD dispatcher in baton rouge la, I'm trying to get her to come up where I am but I think she's going to stay and help the Police Department.
1150. WeatherSpotter
10:07 AM GMT on August 27, 2005
Does anyone thing Hillary Andrews is about half kooo kooo - How she bob's that head and all that I'm surprised she doesn't break her neck...

Where did you see the 940 MB Update?
1149. Dragoon
10:00 AM GMT on August 27, 2005
Pressure is now down to 940 mb.
1148. nola
9:59 AM GMT on August 27, 2005
Still nothing yet from NO officials but I expect that to change very soon. Just got back from Walmart to stock up - traffic was light, just a few people getting gas, no run in the grocery stores. Models look bad for us; only thing worse would be if the eye comes in slightly west of the city. This makes me remember Betsy - 40 years ago. It should get pretty hectic here in the next few hours.
1147. stmarylalady
9:55 AM GMT on August 27, 2005
I am about 85/90 miles(as the crow flies) or so west of NO. I am on the coast, about 8 or 9 miles from Vermilion Bay. But my little town sits on a patch of land that is relatively high compared to the swampland that surrounds it.

We took a direct hit from Andrew and didn't flood. Our house took the beating pretty well also. No trees near our house. Our landlord has cut them all down. LOL. Unfortunately we are a family of 6(was 7 but oldest daughter is safe and sound in north Texas) and only a small truck for transportation.

We are safe from storm surge and flooding. Our biggest risk will be from wind if she ends up coming any closer.

We rode out Andrew and then fled from Lili, who wimped out and made it a wasted trip. All the way to Tyler, Tx.

So far nothing from our parish officials. I figure that will happen later today.
1146. lsugirl
9:50 AM GMT on August 27, 2005
Wow, this is such a great site, you all are so informative! Unfortunately this is a very scary situation! I am in Baton Rouge, and I bet that I-10 is going to be a mess in the morning with early evacuations.
1145. Selu
9:41 AM GMT on August 27, 2005
stmary. Look at the new NHC track. Where are you, in relation to the new track? I'd get the he77 out of dodge, if I were you, if you are within 50 miles of NOLA.
Member Since: February 5, 2004 Posts: 7 Comments: 312
1144. WeatherSpotter
9:41 AM GMT on August 27, 2005
Sure feel for them guys - My girlfriend lives in Baton Rouge - she is a police dispatcher for the City.
1143. Selu
9:39 AM GMT on August 27, 2005
Guys, look at the new NHC Track. Dead center through NOLA. OMG. On the image, see where that 2AM Tuesday dot is? Well, that's about 30 miles northeast of my house.

http://www.nhc.noaa.gov/storm_graphics/AT12/refresh/AL1205W_sm2+gif/085817W_sm.gif
Member Since: February 5, 2004 Posts: 7 Comments: 312

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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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