Grace remnants (Is Invest 96L)

TheStormExpert · #61 Postby **TheStormExpert** » Thu Sep 17, 2015 6:39 am

8 am TWO.

A large area of disturbed weather extending from the southeastern
Gulf of Mexico northeastward across Florida is associated with a
broad surface trough interacting with an upper-level trough. This
system is expected to move northeastward and spread heavy rains over
portions of the Florida peninsula during the next day or two. A low
pressure area could form over the southwestern Atlantic this
weekend, and conditions there could become a little more conducive
for tropical or subtropical cyclone development.
* Formation chance through 48 hours...low...10 percent
* Formation chance through 5 days...low...30 percent

#62 Postby **northjaxpro** » Thu Sep 17, 2015 6:47 am

The Low Pressure area in the SE GOM is looking rather decent this morning, despite the 20 kts + shear values over the GOM currently. There is actually decent spiral banding rotating toward the LLC this morning as indicated on long range Key West radar. Also, surface pressure is gradually dropping, with 1011 mb now being analyzed with the broad LLC at 12Z by NHC and WPC.

I definitely see this being designated as 96L later today. NHC bumped up the percentage for development to 30% earlier this morning for when this system emerges into the Atlantic this weekend. Awaiting the TWO at 8 a.m. due out any minute.

EDIT: Right on cue, the new TWO is out. Still at 30% for the next 5 days.

LarryWx · #63 Postby **LarryWx** » Thu Sep 17, 2015 7:30 am

SW shear still looks strong to me. Am I missing something? The GFS suggests it is still over 20 knots.
Any one else have an opinion about the shear? If it is that strong, could it still develop purely tropically?

#64 Postby **northjaxpro** » Thu Sep 17, 2015 7:36 am

Shear is high in the GOM and it will remain that way. This will not have a real shot.at developing until it moves out into the Atlantic this weekend. The environment at that time may become better to allow sub'tropical or tropical development off the SE U.S. Atlantic coast.

TheAustinMan · #65 Postby **TheAustinMan** » Thu Sep 17, 2015 7:44 am

A plurality of the computer forecast models are not very optimistic as to the possibility of this storm developing in the Gulf of Mexico (or even off the SE US coast later on). However, one particular mesoscale model, the WRF-ARW, has been very bullish with this system over the last few days, and now takes the disturbance all the way up to strong-tropical storm/hurricane intensity less than 24 hours from now. Personally I think this is an unrealistic scenario given the strong wind shear and little model support for such cyclogenesis currently, but nonetheless it does represent the upper-end of model support for this system.

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The posts in this forum are NOT official forecasts 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.

#66 Postby **northjaxpro** » Thu Sep 17, 2015 7:47 am

highly unlikely to come to fruition, not in that fashion. I can't see this Low getting any lower than 1005 or q006.mb at best with the shear. But, we watch for a good reason of course.

LarryWx · #67 Postby **LarryWx** » Thu Sep 17, 2015 7:52 am

My guess as to why the WRF-ARW has it develop so much is that it has the track of the sfc low further south, which keeps it in lower shear. Is it realistic that it would take that far south a track? If so, then maybe it would be onto something.
Also, does anyone know anything about this model's general performance? Is it usually out in left field like the NAM and CMC when they're on their own with strong solutions? If so, then I'd be more apt to just dismiss it as very likely false.

blp · #68 Postby **blp** » Thu Sep 17, 2015 8:22 am

I see an improvement in the vorticity at the 500MB and 700MB levels versus last night. The 500MB is slightly south from the lower level vorticity but much stronger than last night.The 06z GFS holds onto voriticity longer. I think this has a chance to become a depression in the Gulf if it stays a little further south. I think it might be get going further south than the GFS is showing.

EDIT: Even the Euro is showing more vorticity in 24hrs. Could get interesting...

LarryWx · #69 Postby **LarryWx** » Thu Sep 17, 2015 8:32 am

Considering this possibility of a further south track, is that a LLC about 100-125 miles WSW of Naples? The radar makes me wonder and ronjon mentioned this earlier. IF so, then it may be tracking further south than the GFS where shear is under 20 knots.

#70 Postby **lrak** » Thu Sep 17, 2015 8:34 am

I can never understand the steering current map on the Steering Layer 700-850mb - West Atlantic. It shows lines with arrows pointing SW instead of this blob moving NE. Why would it move NE if the steering currents from the Wisconsin website show the arrows pointing SW?

Thanks.

LarryWx · #71 Postby **LarryWx** » Thu Sep 17, 2015 9:23 am

Dang, does the 12Z NAM really have this ~150 miles east of its 6Z NAM position as of hour 33 (near west coast of FL)?

http://mag.ncep.noaa.gov/Image.php?fhr= ... Size=M&ps=

Sanibel · #72 Postby **Sanibel** » Thu Sep 17, 2015 10:36 am

Rain here. Wetlands have bridged over to pond at high water mark for rainy season. Finally a good wet season to recharge the aquifer.

A weak elongated center appears to be off to its west in the Gulf.

Invest?

LarryWx · #73 Postby **LarryWx** » Thu Sep 17, 2015 10:56 am

The 12Z GFS has the sfc low the strongest of at least the last five runs off of the SE Conus coast as of hour 60:

http://mag.ncep.noaa.gov/Image.php?fhr= ... =M&ps=area

Edit: Soon afterward, it turns left and skims NC Outer Banks 9/23-4.

It looks like some part of the SE US may still be affected by this a week from now.

blp · #74 Postby **blp** » Thu Sep 17, 2015 11:36 am

The rotation seen on radar off naples looks to be mid level. The vorticity at the 700 & 800 are further SW and looks to be improving. Also wind shear is easing up to 20kts.

LarryWx · #75 Postby **LarryWx** » Thu Sep 17, 2015 11:44 am

Thanks for clarifying that.

Meanwhile, the 12Z CMC has a totally different solution from both the 12Z GFS and the 0Z CMC.

http://www.tropicaltidbits.com/analysis ... 0&ypos=224

#76 Postby **cycloneye** » Thu Sep 17, 2015 12:35 pm

2 PM TWO:

A large area of cloudiness, showers, and thunderstorms extending
from the eastern Gulf of Mexico across the Florida peninsula and
into the southwestern Atlantic Ocean is associated with a broad
surface low interacting with an upper-level trough. This weather
system will move generally northeastward and continue to produce
heavy rainfall across portions of Florida through Friday. This
weekend and early next week an area of low pressure is expected to
form off the southeast United States coast, where conditions could
become somewhat conducive for subtropical or tropical cyclone
development. For more information on this system, see products from
your local National Weather Service office.
* Formation chance through 48 hours...low...10 percent
* Formation chance through 5 days...low...30 percent

Hurricaneman · #77 Postby **Hurricaneman** » Thu Sep 17, 2015 1:35 pm

out of everything in the basin right now the GOM to east coast disurbance has the best chance at being a named system IMO

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

#78 Postby **NDG** » Thu Sep 17, 2015 2:11 pm

Still a messy disturbance, broad area of low pressure in the eastern Gulf of Mexico with several MLCs rotating around, still too much shear.

Hammy · #79 Postby **Hammy** » Thu Sep 17, 2015 2:18 pm

This reminds me of Gabrielle 2001 sort of setup, though this likely won't stick around long enough to actually develop.

Hurricaneman · #80 Postby **Hurricaneman** » Thu Sep 17, 2015 2:38 pm

The 12zEuro has this landfalling in New Jersey. Interesting

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

Grace remnants (Is Invest 96L)

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