ATL: IRENE - Remnants - Discussion

[WxGuy1]

The following is the UW-CIMSS wind shear analysis from 03 UTC:



That's 20-30 kts of shear over the northern 1/2 of Irene, which puts it almost into the "strong" category. Looking at IR satellite data, Irene certainly looks like it is experiencing some shear problems, though there also be a little bit of dry air entrainment into the storm's circulation as a result of that vertical wind shear.

Honestly, Irene has only look very good to me for a few hours when there was a nice circular eye Wednesday. The eye today has been very intermittent in terms of how well it's evident in satellite data.

As a reminder, the winds are a little weaker than many would expect for a ~940 mb hurricane as a result of the very large size of the wind field. Remember, we're interested in the sea-level pressure gradient, or how quickly the pressure changes over some distance. In the case of Wilma, when it was an intense Cat 5 with a 884-882 mb central pressure, the hurricane-force winds only extended out 15 miles. Yes, fifteen miles. Within that 15 miles, however, the pressure changed extraordinarily (which is an understatement) rapidly; this extreme pressure gradient led to the 150+ kt sustained winds.

Also remember that the strongest winds that you see in the NHC forecasts will likely only be found on the right side (east side) of the hurricane. The left/western side (which happens to be the land side) will likely see considerably weaker winds (20-40 mph weaker) by the time the storm gets to the latitude of NC/VA.

[bob rulz]

This has got to be among the strangest storms I've ever seen. She really can't make up her mind! I left for work to see a storm that appeared to be on the verge of bombing out and I come home to see her looking ragged and weak. It's got to be frustrating for those on the East Coast. The track forecast has been dead on so far, but the intensity forecast has been exceedingly difficult.

[bexar]

that should put a lid to prevent Irene's strengthening

I just didn't buy what air force met had said about Irene awhile ago that she is a deepening system.

models also sure are doing a poor job on Irene.

[gotoman38]

000
URNT15 KNHC 260800
AF304 2409A IRENE HDOB 41 20110826
075030 3029N 07847W 6968 03065 9938 +103 +091 061057 061 052 002 00
075100 3029N 07849W 6966 03067 9941 +101 +089 061053 054 051 001 00
075130 3029N 07852W 6970 03066 9945 +100 +090 060050 051 051 002 00
075200 3030N 07854W 6965 03074 9953 +095 +093 060048 049 053 002 03
075230 3029N 07856W 6962 03076 9956 +092 //// 057047 047 /// /// 05
075300 3027N 07857W 6968 03069 9960 +090 //// 054045 046 /// /// 05
075330 3026N 07855W 6973 03064 9949 +097 +095 052041 042 052 003 03
075400 3025N 07854W 6967 03066 9945 +099 +091 051044 046 052 002 00
075430 3024N 07853W 6967 03065 9939 +101 +088 053046 048 053 000 03
075500 3023N 07851W 6964 03065 9934 +105 +084 053047 048 052 001 03
075530 3022N 07850W 6967 03063 9929 +108 +083 052049 050 052 001 03
075600 3021N 07848W 6967 03060 9923 +110 +084 052049 050 051 003 00
075630 3020N 07847W 6967 03058 9917 +113 +084 049047 048 051 001 03
075700 3019N 07846W 6971 03050 9923 +107 +086 048049 052 051 000 00
075730 3017N 07844W 6965 03055 9927 +098 +093 050047 048 051 002 00
075800 3016N 07843W 6969 03047 9924 +098 //// 059048 048 051 002 01
075830 3015N 07842W 6965 03049 9917 +099 //// 063046 047 051 001 01
075900 3014N 07840W 6967 03043 9914 +100 //// 064045 046 050 003 01
075930 3013N 07839W 6967 03042 9907 +104 //// 065050 051 050 001 01
080000 3012N 07838W 6966 03041 9900 +105 //// 064052 052 049 002 01
$$
;

If anyone wants HDOBS, RECCOS, DROPSONDS, VDMS, or Graphics then the gift is yours

Starting run NW to SE

[caneman]

In terms of track the models are doing a great job! I can only assume you are referring to intensity which of course the models do struggle with.

[ConvergenceZone]

Thanks WXGUY1. Wow, I didn't think it would encounter such strong shear so early. The way they were talking before, I was thinking that the shear wouldn't show up this strong, this early. So that explains it. So now I definately think Irene is on it's way down, and much sooner than anyone anticipated. It will be interesting to see just how low it will go before it makes landfall. Will is still be a hurricane? who knows.... Wow, what a difference a few hours makes!

I'll cross my fingers maybe it will just end up being a huge rainmaker.....

[WxGuy1]

Yeah, there's an upper-tropospheric trough in the southeastern U.S. and northern Gulf of Mexico that is currently stronger than the models indicated it would be (for the geeks, look at the 12480 m isohypse on the 200 mb plots from the GFS yesterday vs. today). This may be the cause of the stronger-than-expected vertical wind shear that Irene is currently experiencing.

I chose the 18 hr fcst (valid Friday around noon) since the isohypse (squiggly lines) illustrate the trough a little better. Its evident in the winds earlier than this forecast (e.g. now) and, even you created your own plots to choose the contour levels appropriately, in the height data as well:

[gotoman38]

000
URNT15 KNHC 260818
AF304 2409A IRENE HDOB 42 20110826
080030 3011N 07836W 6967 03036 9898 +106 //// 066051 051 049 002 01
080100 3010N 07835W 6966 03034 9891 +109 //// 066053 055 050 001 01
080130 3009N 07834W 6967 03028 9880 +114 +110 066055 056 051 003 00
080200 3008N 07833W 6969 03025 9893 +099 //// 065057 059 051 005 01
080230 3006N 07831W 6967 03024 9894 +099 //// 068060 061 051 005 01
080300 3005N 07830W 6967 03021 9887 +100 //// 070062 062 052 004 01
080330 3004N 07829W 6967 03016 9884 +097 //// 067062 062 052 005 01
080400 3003N 07828W 6963 03017 //// +089 //// 066063 064 053 006 01
080430 3002N 07827W 6967 03010 //// +096 //// 068061 063 054 006 01
080500 3001N 07825W 6967 03006 //// +097 //// 067062 063 056 006 01
080530 3000N 07824W 6971 02997 //// +078 //// 067063 064 056 008 01
080600 2959N 07823W 6963 03004 //// +088 //// 068065 068 056 008 01
080630 2958N 07822W 6968 02993 //// +077 //// 067068 070 056 008 01
080700 2957N 07821W 6966 02992 //// +090 //// 066066 068 056 007 01
080730 2956N 07819W 6964 02988 //// +079 //// 068069 070 057 007 01
080800 2955N 07818W 6971 02977 //// +094 //// 066066 067 054 008 01
080830 2954N 07817W 6965 02982 //// +096 //// 064066 067 055 005 01
080900 2953N 07816W 6970 02971 //// +089 //// 063065 067 057 007 01
080930 2952N 07815W 6967 02969 //// +090 //// 060061 062 059 008 01
081000 2951N 07813W 6970 02963 9819 +105 //// 058063 064 058 005 01
$$
;

[bexar]

NY should get lucky this time.

[ConvergenceZone]

Yeah, there's an upper-tropospheric trough in the southeastern U.S. and northern Gulf of Mexico that is currently stronger than the models indicated it would be (for the geeks, look at the 12480 m isohypse on the 200 mb plots from the GFS yesterday vs. today). This may be the cause of the stronger-than-expected vertical wind shear that Irene is currently experiencing.

Wow, I can't believe how much good luck we are having this morning, this is awesome news, and at the right time!!!!! I can't wait to turn on the weather channel later to hear the new updates..... (all the weather channel segments now I think are recorded from earlier).

[gotoman38]

000
URNT15 KNHC 260820
AF304 2409A IRENE HDOB 43 20110826
081030 2950N 07812W 6964 02964 9814 +106 //// 057065 066 056 006 01
081100 2949N 07811W 6966 02956 9812 +103 //// 057064 065 055 009 01
081130 2948N 07809W 6973 02943 //// +100 //// 054064 065 056 009 01
081200 2946N 07808W 6964 02948 9799 +099 //// 054068 069 058 007 01
081230 2945N 07807W 6967 02941 9790 +107 //// 054071 073 058 006 01
081300 2944N 07806W 6966 02935 9773 +115 +114 051072 073 060 007 00
081330 2943N 07804W 6969 02925 9765 +117 +116 048073 073 062 010 00
081400 2942N 07803W 6966 02924 9777 +100 //// 045075 076 061 016 01
081430 2941N 07802W 6967 02915 //// +076 //// 043071 073 063 021 01
081500 2940N 07800W 6966 02911 //// +078 //// 039071 076 063 020 01
081530 2939N 07759W 6974 02897 //// +083 //// 048076 080 066 027 01
081600 2937N 07758W 6944 02920 //// +087 //// 062064 073 067 013 05
081630 2936N 07756W 6994 02848 //// +106 //// 048048 051 067 006 01
081700 2935N 07755W 6967 02874 //// +120 //// 042049 051 066 006 01
081730 2934N 07754W 6963 02871 9686 +128 //// 041050 050 062 005 01
081800 2933N 07752W 6970 02857 9684 +122 //// 042053 053 061 005 01
081830 2931N 07751W 6969 02848 9676 +121 //// 037053 054 057 005 01
081900 2930N 07749W 6965 02846 9658 +130 //// 037055 055 059 002 01
081930 2929N 07748W 6969 02833 9650 +129 //// 037054 054 058 002 01
082000 2928N 07746W 6965 02830 9636 +134 //// 035054 055 057 002 01
$$
;

[Chacor]

On IR, you really can't make out Irene's eye at all. Unfortunately no recent microwave passes on NRL...

[HurricaneBill]

Guys, this is still a dangerous storm. Don't write it off even if it is weakening. People were doing the same thing when Isabel and Frances were hit by dry air and shear. We all know how those storms turned out.

[gotoman38]

000
URNT15 KNHC 260830
AF304 2409A IRENE HDOB 44 20110826
082030 2926N 07745W 6965 02819 9619 +137 //// 033056 056 057 001 05
082100 2925N 07744W 6969 02805 9604 +143 //// 033057 058 053 001 01
082130 2924N 07742W 6972 02788 9590 +144 //// 032059 061 053 001 01
082200 2923N 07741W 6965 02787 9568 +151 //// 028059 059 051 002 01
082230 2921N 07739W 6967 02771 9549 +156 //// 023060 061 052 001 01
082300 2920N 07738W 6966 02759 9523 +168 +159 020061 062 051 002 00
082330 2919N 07736W 6966 02746 9501 +173 +162 012059 061 052 001 00
082400 2917N 07734W 6972 02721 9481 +176 +166 010056 057 055 001 03
082430 2916N 07733W 6963 02717 9449 +191 +170 004055 057 054 001 03
082500 2916N 07731W 6961 02697 9426 +190 +174 003052 056 052 003 00
082530 2915N 07729W 6975 02658 9413 +183 +178 002037 043 043 002 00
082600 2915N 07727W 6967 02656 9406 +175 //// 348026 029 038 002 01
082630 2915N 07724W 6971 02644 9408 +163 //// 343008 018 028 004 05
082700 2915N 07723W 6969 02642 9392 +176 //// 102010 013 024 002 01
082730 2916N 07721W 6974 02629 9391 +173 //// 111011 012 023 002 05
082800 2915N 07720W 6968 02636 9398 +164 //// 176009 011 /// /// 05
082830 2914N 07721W 6966 02637 9392 +171 //// 206005 007 022 002 05
082900 2914N 07722W 6971 02635 9398 +170 //// 304006 012 024 001 05
082930 2913N 07724W 6968 02646 9399 +175 //// 313021 026 029 003 01
083000 2913N 07726W 6963 02661 9393 +188 +183 332033 036 036 002 00
$$
;

[gotoman38]

000
URNT15 KNHC 260840
AF304 2409A IRENE HDOB 45 20110826
083030 2913N 07728W 6966 02669 9406 +189 +184 342041 043 042 003 00
083100 2913N 07730W 6972 02682 9438 +178 //// 337052 056 048 002 01
083130 2912N 07732W 6960 02712 9445 +185 +185 336061 061 052 002 00
083200 2912N 07732W 6960 02712 9459 +187 +185 341061 062 054 003 00
083230 2912N 07735W 6968 02734 9492 +172 //// 343061 063 055 001 01
083300 2912N 07737W 6962 02758 9512 +166 //// 345063 063 055 001 01
083330 2911N 07739W 6981 02749 9529 +167 //// 345061 062 054 001 01
083400 2911N 07741W 6963 02785 9551 +162 //// 345060 061 052 002 01
083430 2911N 07743W 6963 02796 //// +156 //// 344057 058 050 001 01
083500 2911N 07745W 6970 02798 9575 +161 //// 347057 058 049 001 01
083530 2910N 07747W 6963 02816 9589 +152 //// 348057 058 049 002 01
083600 2910N 07749W 6967 02821 //// +141 //// 348056 056 048 001 01
083630 2910N 07750W 6968 02826 //// +144 //// 346056 057 047 001 01
083700 2910N 07752W 6967 02836 //// +135 //// 344056 058 047 002 01
083730 2909N 07754W 6974 02833 //// +134 //// 344057 058 049 001 01
083800 2909N 07756W 6970 02844 9647 +141 //// 343057 058 051 002 01
083830 2909N 07758W 6969 02852 9649 +146 //// 343057 057 053 003 01
083900 2909N 07800W 6965 02864 9648 +153 +153 347058 060 058 002 00
083930 2908N 07802W 6973 02859 9651 +155 +152 349060 061 061 003 00
084000 2908N 07803W 6961 02880 9657 +156 +152 345058 059 065 005 00
$$
;

Looks like they're headed back to base

[gotoman38]

000
URNT12 KNHC 260842
VORTEX DATA MESSAGE AL092011
A. 26/08:26:40Z
B. 29 deg 15 min N
077 deg 24 min W
C. 700 mb 2607 m
D. 67 kt
E. 304 deg 35 nm
F. 050 deg 80 kt
G. 304 deg 38 nm
H. 943 mb
I. 8 C / 3049 m
J. 19 C / 3053 m
K. 17 C / NA
L. OPEN ESE-S-W
M. C20
N. 12345 / 7
O. 0.02 / 1 nm
P. AF304 2409A IRENE OB 22
MAX FL WIND 110 KT NE QUAD 07:00:00Z
MAX FL TEMP 20 C 278 / 6 NM FROM FL CNTR
BARELY HALF THE EYEWALL REMAINING. STRONGEST FL WINDS NOW ASSOC WITH SPIRAL BAND
WHICH MAY BECOME NEW EYEWALL.
;

[ncbird]

If this turns out to be a weaker storm than predicted, that of course is good news to all in its path. But I would like put up a caution for those who are new to dealing with these systems. DON'T LET YOUR GUARD DOWN! Just because a system does not have major status does not mean your in the clear. Even a tropical storm can do major damage. This is a large system that will be producing constant wind and rain for many many hours, and can still cause dangerous flooding to those in it path.

Please all be safe.

[gotoman38]

000
URNT15 KNHC 260850
AF304 2409A IRENE HDOB 46 20110826
084030 2908N 07805W 6980 02860 9679 +142 //// 342056 057 062 005 01
084100 2908N 07807W 6962 02888 //// +122 //// 348055 055 062 008 01
084130 2907N 07809W 6969 02895 //// +094 //// 355068 074 062 008 01
084200 2907N 07811W 6962 02904 9723 +114 //// 358078 083 060 007 01
084230 2907N 07813W 6978 02894 9732 +126 //// 357076 084 060 001 01
084300 2906N 07815W 6967 02916 9738 +128 +124 355069 072 061 001 00
084330 2906N 07817W 6967 02922 9750 +126 +123 354070 071 061 004 00
084400 2906N 07819W 6970 02925 9758 +123 +122 351070 071 059 004 00
084430 2906N 07820W 6965 02938 9762 +127 +119 352068 070 059 004 00
084500 2905N 07822W 6964 02947 9771 +125 +115 352066 067 059 003 00
084530 2905N 07824W 6972 02943 9779 +126 +111 354063 064 058 003 00
084600 2905N 07826W 6970 02954 9785 +130 +108 352061 062 059 003 00
084630 2905N 07828W 6967 02964 9795 +127 +108 350059 060 058 002 00
084700 2904N 07830W 6970 02966 9802 +125 +107 349058 059 057 001 03
084730 2904N 07832W 6962 02979 9811 +122 +108 350057 058 054 001 03
084800 2904N 07834W 6970 02977 9824 +117 +110 349056 057 054 001 00
084830 2904N 07836W 6969 02981 9825 +119 +111 347055 056 054 000 03
084900 2903N 07837W 6965 02989 9835 +113 +113 345052 054 054 001 03
084930 2903N 07839W 6969 02987 9846 +105 //// 347050 051 052 001 01
085000 2903N 07841W 6965 02994 9850 +105 //// 343049 050 052 001 05
$$
;

[funster]

If the pressure starts rising then the cheering and joy can commence. So far the pressure has only been falling despite the increased sheer, which is sad and bad. There is absolutely nothing to be happy about here. Only sadness, concern and despair as a powerful hurricane heads for the most populated regions of the U.S.

23 GMT 08/20/11 14.9N 58.5W 50 1006 Tropical Storm
03 GMT 08/21/11 15.3N 59.9W 50 1006 Tropical Storm
09 GMT 08/21/11 16.4N 61.3W 50 1006 Tropical Storm
15 GMT 08/21/11 17.0N 63.2W 50 1007 Tropical Storm
21 GMT 08/21/11 17.7N 64.4W 50 999 Tropical Storm
03 GMT 08/22/11 17.9N 65.5W 70 993 Tropical Storm
09 GMT 08/22/11 18.4N 66.4W 75 987 Category 1 Hurricane
15 GMT 08/22/11 19.2N 67.5W 80 988 Category 1 Hurricane
21 GMT 08/22/11 19.5N 68.6W 80 988 Category 1 Hurricane
00 GMT 08/23/11 19.7N 68.7W 100 981 Category 2 Hurricane
03 GMT 08/23/11 19.9N 69.2W 100 980 Category 2 Hurricane
09 GMT 08/23/11 20.3N 70.1W 100 978 Category 2 Hurricane
15 GMT 08/23/11 20.5N 71.0W 100 980 Category 2 Hurricane
21 GMT 08/23/11 20.9N 71.5W 90 976 Category 1 Hurricane
03 GMT 08/24/11 21.3N 72.4W 90 969 Category 1 Hurricane
09 GMT 08/24/11 21.6N 72.9W 110 962 Category 2 Hurricane
15 GMT 08/24/11 22.4N 73.9W 115 956 Category 3 Hurricane
21 GMT 08/24/11 23.1N 74.7W 120 954 Category 3 Hurricane
03 GMT 08/25/11 23.8N 75.4W 120 952 Category 3 Hurricane
09 GMT 08/25/11 24.6N 76.2W 115 950 Category 3 Hurricane
15 GMT 08/25/11 25.9N 76.8W 115 951 Category 3 Hurricane
21 GMT 08/25/11 27.0N 77.3W 115 950 Category 3 Hurricane
03 GMT 08/26/11 28.3N 77.3W 115 942 Category 3 Hurricane

[Chacor]

THE HURRICANE WATCH FROM THE NORTH CAROLINA/VIRGINIA BORDER TO SANDY
HOOK NEW JERSEY...INCLUDING DELAWARE BAY AND CHESAPEAKE BAY SOUTH
OF SMITH POINT IS CHANGED TO A HURRICANE WARNING.

THE TROPICAL STORM WATCH FOR CHESAPEAKE BAY FROM SMITH POINT
NORTHWARD AND THE TIDAL POTOMAC IS CHANGED TO A TROPICAL STORM
WARNING.

A HURRICANE WATCH HAS BEEN ISSUED FROM NORTH OF SANDY HOOK NEW
JERSEY TO THE MOUTH OF THE MERRIMACK RIVER...INCLUDING LONG
ISLAND...LONG ISLAND SOUND...BLOCK ISLAND...MARTHAS VINEYARD AND
NANTUCKET.

HURRICANE CENTER LOCATED NEAR 29.3N 77.2W AT 26/0900Z
POSITION ACCURATE WITHIN 15 NM

PRESENT MOVEMENT TOWARD THE NORTH OR 360 DEGREES AT 12 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 942 MB
EYE DIAMETER 20 NM
MAX SUSTAINED WINDS 95 KT WITH GUSTS TO 115 KT.