Invest 90L:East Atlantic,Discussions,Analysis and Sat Pics

[MiamiensisWx]

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

I'm going out on a limb, but with careful observations, I'm beginning to doubt the validity of an East Coast system (north of FL and GA). Currently, the trough off the Northeast appears to be pulling out, and it is leaving a weakening piece of energy beneath a building upper ridge. That trend would not be sufficient to induce a weakness, even if 90L will develop more rapidly as it approaches the islands. Additionally, the upper low in the southeastern Gulf of Mexico continues to retrograde westward, while the Caribbean system has been showing no signs of further organization (kept in check via strong upper divergence and too much low-level shear). It looks like the Caribbean disturbance may not develop before it interacts with the Yucatan Peninsula. The unfolding synoptic setup is ominous, IMO - this is a classic scenario that has preceeded many long-tracked systems, none of whom made landfall north of FL (synoptics closely resemble the upper-air pattern for Gilbert, Claudette, and other systems).

This trend is an indication of big (potential) implications for 90L. The model guidance appears to be latching on to the strong upper ridge over the southern Plains and Southeast. The quick forward motion of 90L (approximately 20 mph) could continue over the next few days (possibly longer because of the deep layered subtropical ridge). That factor would reduce the odds of a northward trend, and recent data seems to support some models' suggestions. Additionally, if 90L does move north of the Leeward Islands, the trough would seem to weaken by this time - the Euro remains consistent in its attempts to close the weakness when the system nears the southeastern Bahamas. The strong low that was originally progged over the Plains does not receive ample support from the longwave pattern, so we could witness a series of weak shortwaves "pumping" the 500 mbar ridge over the Southeast. That would fortell an ominous sign for the Florida peninsula and Gulf of Mexico - the most northward projections (per current synoptics) would place the system over the Bahamas when the ridge "bridges" the gap, which would induce another turn to the west.

Here's some supporting evidence:

http://www.ssd.noaa.gov/goes/east/natl/loop-ir2.html

There are no indications for a significant breakdown in the pattern; note the series of weak shortwaves moving over the strengthening Southeast ridge, and most guidance does not bring the next significant disturbance into the Pacific Northwest until the end of this week (90L's fast forward motion would bring it to the Caribbean or islands earlier than progged, which would negate this system's effects).

It is too early to draw specific conclusions, but I think we could see a real threat to the islands - I do not see an East Coast impact. The increasingly evident setup is starting to strongly suggest an impact to the islands, FL, Caribbean, or Gulf of Mexico.

On another note, I think we may see a TD by 5 or 11 p.m. EDT, IMO.

Edit: I decided to "clear the air" - I'm not specifically highlighting a landfall location, but I feel these general regions could be at risk (based on my personal observations).

[miamicanes177]

Code: Select all

966
WHXX01 KWBC 121828
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1828 UTC SUN AUG 12 2007
 
DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.
 
ATLANTIC OBJECTIVE AIDS FOR
 
DISTURBANCE INVEST (AL902007) 20070812 1800 UTC
 
        ...00 HRS...   ...12 HRS...   ...24 HRS. ..   ...36 HRS...
        070812  1800   070813  0600   070813  1800   070814  0600
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS    12.4N  25.6W   13.6N  28.7W   14.6N  32.6W   15.7N  37.1W
BAMD    12.4N  25.6W   12.6N  29.8W   12.8N  34.0W   13.0N  38.2W
BAMM    12.4N  25.6W   13.1N  29.5W   13.7N  33.8W   14.1N  38.2W
LBAR    12.4N  25.6W   12.5N  29.2W   12.8N  33.4W   13.1N  37.9W
SHIP        25KTS          27KTS          31KTS          36KTS
DSHP        25KTS          27KTS          31KTS          36KTS
 
        ...48 HRS...   ...72 HRS...   ...96 HRS. ..   ..120 HRS...
        070814  1800   070815  1800   070816  1800   070817  1800
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS    16.9N  42.1W   18.6N  52.3W   19.8N  62.2W   19.3N  71.9W
BAMD    13.3N  42.3W   14.0N  50.5W   15.0N  58.4W   15.6N  65.2W
BAMM    14.6N  42.9W   14.7N  52.6W   13.9N  61.2W   13.6N  67.0W
LBAR    13.4N  42.7W   13.5N  50.6W     .0N    .0W     .0N    .0W
SHIP        42KTS          54KTS          65KTS          70KTS
DSHP        42KTS          54KTS          65KTS          70KTS
 
         ...INITIAL CONDITIONS...
LATCUR =  12.4N LONCUR =  25.6W DIRCUR = 275DEG SPDCUR =  16KT
LATM12 =  12.2N LONM12 =  22.3W DIRM12 = 275DEG SPDM12 =  17KT
LATM24 =  11.8N LONM24 =  19.5W
WNDCUR =   25KT RMAXWD =   35NM WNDM12 =   25KT
CENPRS = 1008MB OUTPRS = 1011MB OUTRAD =  140NM SDEPTH =   M
RD34NE =    0NM RD34SE =    0NM RD34SW =    0NM RD34NW =   0NM
 
$$
NNNN


[cycloneye]

Is the first run that SHIP goes to hurricane intensity.

[Brent]

SHIPS up to a hurricane now at 96 hours which should be before it reaches the Lesser Antilles.

[Scorpion]

I don't even think Florida will be getting this now... it looks like an Ivan-like track perhaps into the GOM or Mexico

[windstorm99]

I don't even think Florida will be getting this now... it looks like an Ivan-like track perhaps into the GOM or Mexico

There's absolutely no way off telling were this system is going in 7-10 days....Right now the main concern is the islands and after that its anybodys guess.Adrian

[ConvergenceZone]

I don't even think Florida will be getting this now... it looks like an Ivan-like track perhaps into the GOM or Mexico

The local weather guy here also just said that it looks like this may be more of a Mexico threat down the road, but I guess we'll just have to wait and see, like ya said, it's early...

[ekal]

I don't even think Florida will be getting this now... it looks like an Ivan-like track perhaps into the GOM or Mexico

The best indications are, now, that it slides to the south of us. However, we are dealing with a system that is still near the Cape Verde Islands. Those best indications, we all know, will change many times in the coming days. There is no reason, therefore, to really think that anyone between the Lesser Antilles and the FL-GA line is more at risk than another location within that area. We just have to wait and see. I agree with MiamiensisWx that the evolution of the weakness that develops to the north of the Greater Antilles later this week is crucial in determining the exact track of the system.

[RL3AO]

Forecasting a Mexico, a GOM or Florida landfall is USELESS!

[El Nino]

SHIP respecting the tendancy making this system a hurricane approaching the Islands. And I thinkit's only the beginning. I'm going for a cat2 in the Islands, and a major short after this place. I have a friend who worked in Haiti and I'll talk to him because this poor land is under a big risk !

[JonathanBelles]

I am also beginning to rule out the northerly option because too many models are taking it south of the islands. I know that the models can change, but haven't done so thus far in terms of going north. There has been a trend to the south.

[Derek Ortt]

newer version of SHIPS is far less aggressive and has been

just looked at the sats, and I would NOT upgrade at 5... has a little while to go yet

[hurricanefloyd5]

well I hope the that if this is a fish so and i doubt it is then let this puppy blow to a Cat.5 cane for all i care but let's hope if it acrosses any land mass then let's hope everyone stays safe lol!!!!!!!!

[cycloneye]

Look how almost all the models are tightly clustered.

[wxman57]

The problem with looking at IR imagery is that you're not looking at the surface, you're looking 5 miles above the surface. Take a look at a visible image and you can see why 90L won't be upgraded yet. The center is exposed well east of the convection. I measured the forward speed at 19.1 kts the past 12 hours. It'll have to slow down before it can organize. If it keeps up this speed it'll reach the eastern Caribbean a day sooner - Thursday afternoon. But it won't be as strong moving so fast.

[Cyclone1]

It has an exposed LLC, but it has a discernible LLC. That's something.

[ekal]

The problem with looking at IR imagery is that you're not looking at the surface, you're looking 5 miles above the surface. Take a look at a visible image and you can see why 90L won't be upgraded yet. The center is exposed well east of the convection. I measured the forward speed at 19.1 kts the past 12 hours. It'll have to slow down before it can organize. If it keeps up this speed it'll reach the eastern Caribbean a day sooner - Thursday afternoon. But it won't be as strong moving so fast.

That easterly speed shear again. Looking at the sounding from the CVs, those are some fast winds right above the surface.

[srainhoutx]

The problem with looking at IR imagery is that you're not looking at the surface, you're looking 5 miles above the surface. Take a look at a visible image and you can see why 90L won't be upgraded yet. The center is exposed well east of the convection. I measured the forward speed at 19.1 kts the past 12 hours. It'll have to slow down before it can organize. If it keeps up this speed it'll reach the eastern Caribbean a day sooner - Thursday afternoon. But it won't be as strong moving so fast.

Thanks wxman57. Enjoy your day off as things are getting interesting Basin Wide

[ConvergenceZone]

Those models don't scream USA anymore that's for sure, and they all seem to be in good agreement.....Mexico/C America needs to keep an eye out for this storm...I've got some friends down in Mexico(fairly close to the shoreline), I'm going to let them know about this pronto just in case...

[Derek Ortt]

wont it need to speed up since the upper easterlies are faster than the low level flow? If it slows down, wouldn't that increase the easterly shear?