MikeC
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The latest recon shows about the same windspeed as in the advisory, and the pressure down to 926mb, and since the next two or three days are going to be critical for the ultimate mainland landfall location, I'm sure there is a lot of "no it's moving more north-- no it's moving more west" type of observations, which are always interesting...
Intense Hurricanes with eyes like Dean tend to wobble around like a spinning top, and it's hard to gauge if something is a trend, or a wobble. The SSD satellites with the forecast track overlays are helpful here, but I think bare minimum is a 4 frame change to really see if something is a wobble or a true movement.
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dem05
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Good morning everyone, I got a few messages from folks that were kind of hoping that I would have put some more meat and potatoes into my post last night, so I will try and do that this morning. Sorry 'bout that guys! 
First, NLU is certainly correct...I also agree with this mornings post that we may be getting closer to "moments of truth" on the interaction of the ULL. Dean has broken free of Route 15 as I am sure that most of you have noticed this already morning. There are one of two thoughts toward this mornings motion. The first one is more straightforward and in line with my thinking last night. Second one will be many hours away from any confirmation.
- Thought 1: As Dean had done yesterday, he is moving a little north of track. Later this evening we may se him bend more to the west again like he did last night, when at 15 degrees north. If so, the overall average motion would basically be in line with the forecast track.
-Thought 2: Dean may be getting close enough to the "Bahamas ULL" (Which I will now refer to as the FL ULL), to feel some of the effects. I am giving option 2 a little more weight this morning than I would have when I posted last night. However, my reasoning for this is not due to the Satellite motion, which is depicting a more northward component. If there is any hint that this wobble may be indicative of some interaction with the ULL, the indication is in Dean’s forward speed. In this mornings 5AM Discussion, the has stated that the forward speed of Dean has decreased again. It would be expected that if Dean was going to feel some of the effects of the ULL, then Dean would have to get close enough to the ULL that it would approach the edge of the ridge...Hence, the forward speed would decrease. While Dean has closed the gap on the ULL over the last few days, I don't think it has closed the gap enough to feel any big influence...However, this may be a sign of things to come. So forward speed will be something to watch today and I imagine there will be some more ground truth as to whether or not this maybe what is going on in about 24 hours or so.
I'd like to take some time to review this morning’s satellite loops and data in a little more detail, but I'll be back in a bit with another post this morning.
Edited by dem05 (Sat Aug 18 2007 12:36 PM)
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madmumbler
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Loc: SWFL
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Quote:
<<snipped>>While Dean has closed the gap on the ULL over the last few days, I don't think it has closed the gap enough to feel any big influence...However, this may be a sign of things to come. So forward speed will be something to watch today and I imagine there will be some more ground truth as to whether or not this maybe what is going on in about 24 hours or so.
So are we rooting for Dean to speed up or slow down? *LOL*
What is our "best case" scenario that we want to look for to see Dean doing in relation to the ULL? And what is the "worst case?" (Considering I'm in FL, best case means not making a hard turn *LOL* -- sorry everyone in the west!)
I'm NOT panicking or worrying. I know that everything is still up in the air. But i heard talking about the ULL this morning and last night, and I'm still not sure what is "good" and what is "bad" in terms of Dean's movement and forward speed. (Obviously, it's all "bad" in the long run because wherever this hits is going to get whomped.)
Thanks,
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Lesli in SWFL.
Friends help you move. Real friends help you move bodies.
Edited by madmumbler (Sat Aug 18 2007 12:43 PM)
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mp3reed
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Loc: Abilene, Texas USA
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My rain gauge this morning is at 5 1/2 inches. Last 24 hours.
Erin is still making it's mark here in Abilene and west Texas.
If Dean heads this way, it can't be good.
Lot's of flooding this morning.
Lakes are above spillway.
So much for hot dry west Texas.
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craigm
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Loc: Palm City, Florida
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Dean is almost on top of this bouy located at 15.01N 67.5
http://www.ndbc.noaa.gov/station_page.php?station=42059&unit=E&tz=EST
Actually, looking at the wind speed, direction and pressure it looks like Dean passed just to the north about 4 hrs ago
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Why I'm here:
Weather hobbyist
Edited by craigm (Sat Aug 18 2007 01:04 PM)
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CaneTrackerInSoFl
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By the way, has Dean's pressure down to 924 mbs.
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Andrew 1992, Irene 1999, Katrina 2005, Wilma 2005
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MikeC
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Some interesting signs to watch to see if they hold. Seems like the (and thusly a lot of models based on it) initialized the Upper Level Low over Florida much much too weak, and are downplaying it too much. Also the slight jog north of Dean is a bit troubling. Not saying it really means much now, bu the potential is there for changes to happen. So it may be a good idea to keep close watch on these two things and see if they persist over the next several hours or not.
It will be very interesting to see what newer model runs do with all this, it's very important.
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charlottefl
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Everyone has been paying attention to the ULL in the Bahamas, which is obviously important to the track of Dean.
I'm curious though. The hurricane has slowed it's forward motion. There is a 2nd ULL to the NE of Dean gaining ground
on Dean. Will this ULL have any impact on the future track of Dean? Lots of variables in the track of these storms.
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flanewscameraman
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Loc: Palm Beach County, FLA
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A question for those of us not versed in the sciences. Would the effect of the ULL over Florida be to erode somewhat the ridge that is keeping Dean on a Westward heading, and thus allow it to take more of a WNW or NW jog.
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Thunderbird12
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Loc: Oklahoma
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Dean has resumed its WNW after moving due west for much of the evening last night, but overall it appears to be right on track (unfortunately) for Jamaica. While it is slightly north of the projected path at its current position, keep in mind that the last forecast had a more westerly motion early in the period before more of a turn to the WNW towards Jamaica. Dean will end up right on the forecast track again around Jamaica if it keeps its present bearing long enough.
The 06Z came in a lot further south. It is still on the northern fringe of guidance, but brings Dean through the Yucatan for the first time before heading into the Gulf and making landfall in south Texas.
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danielw
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Quote:
139
URNT12 KNHC 181212
VORTEX DATA MESSAGE AL042007
A. 18/11:51:20Z
P. AF304 0604A DEAN OB 03
MAX FL WIND 145 KT NE QUAD 11:48:40 Z
SMALL HAIL INBOUND NE QUAD
RADAR PRESENTATION EXCELLENT
Small hail is usually indicative of a storm trying to gain More intensity. Also unnerves the flight crew to some degree.
Imagine hail hitting your car while traveling at 300 mph instead of 60mph. 
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Hugh
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Quote:
Small hail is usually indicative of a storm trrying to gain More intensity. Also unnerves the flight crew to some degree.
Imagine hail hitting your car while traveling at 300 mph instead of 60mph.
The 8am advisory mentioned that the satellite presentation of Dean over the last several hours hinted at some weakening, yet all signs I have read from the recon - small hail, and pressure now down to 920mb according to one report I saw - indicate that Dean is on the verge of the Cat 5 threshhold, if not already on the other side of it. Why did the mention the possibility of weakening based upon satellite images?
Edit: Read latest vortex message which shows pressure actually UP to 929mb, so go figure
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Hugh
Eloise (1975) - Elena and several other near misses (1985) - Erin & Opal (1995) - Ivan (2004)
Edited by Hugh (Sat Aug 18 2007 01:47 PM)
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Random Chaos
Weather Analyst
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Loc: Maryland
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New recon:
090
URNT12 KNHC 181340
VORTEX DATA MESSAGE AL042007
A. 18/13:23:30Z
B. 15 deg 28 min N
068 deg 14 min W
C. NA mb 2475 m
D. 102 kt
E. 122 deg 006 nm
F. 220 deg 117 kt
G. 125 deg 007 nm
H. 929 mb
I. 11 C/ 3046 m
J. 18 C/ 3045 m
K. 12 C/ NA
L. CLOSED
M. C12
N. 12345/7
O. 0.02 / 2 nm
P. AF304 0604A DEAN OB 09
MAX FL WIND 145 KT NE QUAD 11:48:40 Z
RADAR PRESENTATION EXCELLENT
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Random Chaos
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Loc: Maryland
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Looking at satellite, it appears that there was some disruption in the western portions of the system. This disruption appears to have closed up and the storm looks beautiful on IR now. In fact, the storm looks to be growing in size.
Latest recon recorded a drop in wind speeds and rise in pressure, so we can assume that is the weakening that mentioned might occur. Based on radar, I suspect next recon will show the system re-strengthened.
Also, the strongest winds seem to have been in the NW quad, where the recon plane didn't pass through this time.
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tekkrite
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The wave at about 10N 35W looks more formidable than Dean did at that point, and is starting to form up. Any observations from the mets here?
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danielw
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Loc: Hattiesburg,MS (31.3N 89.3W)
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Probably because the "weakening flag" has been turned on as of 0845Z per the AODT page.
http://cimss.ssec.wisc.edu/tropic/adt/04L-list.txt
And Dean looks rather weak here:
Dean
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Thunderbird12
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The satellite indicated the possibility of some weakening because the cloud tops had warmed somewhat and the was somewhat asymmetric. Based on the latest recon (pressure back up to 929 mb), it seems to have peaked momentarily in intensity. Cloud tops around the center have begun to cool again on the last few frames, so it may attempt to begin another intensification cycle soon.
The warmest waters of the Caribbean are still further west, so it may be about as strong as the environment will allow right now.
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h2ocean
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tekkrite, yeah, I have been watching to the east of Dean. Models are picking up on one or two features out there. Here is an exceprt from the Melbourne, FL NWS discussion early this morning:
EXTENDED...STRONG TROPICAL WAVE OR POSSIBLY CLOSED LOW INDICATED BY
GFS APPROACHING BAHAMAS IN EASTERLIES LATE WED/EARLY THU WITH
MOVEMENT TOWARD S FL ON THU AND THERE IS SOME REFLECTION OF THIS
WAVE AS WELL IN . SYSTEM IS SHOWN INTERACTING WITH AN EAST
COAST TROUGH AND PULLING NWD ALONG THE FL EAST COAST SLOWLY ON FRI
AND INTO SAT. HAVE INCREASED POPS AND OTHER FORECAST ELEMENTS TO
REFLECT THIS BUT HAVE DECREASED WINDS OVER THE MARINE AREA AT THIS
EARLY JUNCTURE DUE TO UNCERTAINTIES.
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Merritt Island, FL Home Weather Station
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HanKFranK
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i'm still not sure what to make of dean's jogs. don't suspect that the relationships for steering that existed yesterday have changed all that much, as dean has bled some speed and is making up for the due westward motion in the evening. model guidance is more to the left (though some of the upper initializations are called into question for the ) overall... same basic camps persist. i don't think we'll see much aside from the official today or tomorrow, with the only interesting side notes being how the hurricane interacts with the caribbean islands. be interesting to see if hispaniola and then maybe cuba do the windfield-warp thing and tug the hurricane north of jamaica.
back behind dean it's hard to make any sense of the wave jumble. the one behind dean slowed down so that it's follower is catching it... with most of its energy shunting ahead off to the north, and the leader tucking up underneath closer to the . it's hard to resolve how this complex mess will initiate another system. the part going by to the north is progged to get north of the islands and interact with the upper trough off the east coast, split some, and have a bit of its energy drift towards the bahamas. makes a storm out of this (has for days), while the other globals see just an inverted trough. none of the models buy much into the leader wave east of the islands, with outflow from dean washing over it. the bump further east from the trailer wave seems to spawn another system on the suite, though, and that creates another storm on it by next weekend. hard to trust exactly what the is thinking from there.. it moves nw towards a then large trough near the east coast, and ends up in the gulf by labor day weekend. of course these individual features can't be trusted right now, only watched for persistence. the niggardly way the has suggested tropical activity this season and it's seeming enthusiasm for sending more to the table has me thinking that there will be something there regardless of whether the details are close to right.
HF 1412z18august
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OUSHAWN
Weather Guru
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Loc: Clear Lake,Tx
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Well, looks likw this will be a Mexico storm. The models are starting to all agree on that...even the is really coming south to almost the Mex/Tex. border. Looks like the US really dodged a huge bullet on this one. Looks like there won't be anymore back and forth with the models now. Man I feel alot better now.
Shawn
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