ATL : TROPICAL DEPRESSION ERIKA (06L)

[gatorcane]

so we are saying its not going to hit a weakness anytime soon? Now there is a ridge building in?

What happened to the ULL that was supposed to pull it more NW?

[wxman57]

Here's a recent analysis. The buoy reported a calm wind as the very weak LLC passed. Now it has a 5kt southerly wind. Lowest pressure was 1010mb.

[gatorcane]

12Z NAM image:

[tolakram]

http://rammb.cira.colostate.edu/product ... 051130.GIF

At least I can see the low level rotation, but it looks messy (amateur observation!) and I see outflow boundaries.

Don't 94L invests have a long and storied history of fooling sk2 members?

[Evil Jeremy]

Flights for tomorrow:

000
NOUS42 KNHC 311300
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
0900 AM EDT MON 31 AUGUST 2009
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 01/1100Z TO 02/1100Z SEPTEMBER 2009
TCPOD NUMBER.....09-095

I. ATLANTIC REQUIREMENTS
1. SUSPECT AREA (APPROACHING THE LESSER ANTILLES)
FLIGHT ONE - TEAL 75
A. 01/1800Z
B. AFXXX 01BBA INVEST
C. 01/1600Z
D. 17.5N 56.5W
E. 01/1730Z TO 01/2200Z
F. SFC TO 10,000 FT

FLIGHT TWO - TEAL 76
A. 02/0600Z, 1200Z
B. AFXXX 0206A CYCLONE
C. 02/0400Z
D. 18.0N 58.0W
E. 02/0530Z TO 02/1200Z
F. SFC TO 10,000 FT

2. OUTLOOK FOR SUCCEEDING DAY: CONTINUE 6-HRLY FIXES
IF SYSTEM DEVELOPS AND IS A THREAT.

II. PACIFIC REQUIREMENTS
1. HURRICANE JIMENA
FLIGHT ONE - TEAL 71
A. 01/1500Z
B. AFXXX 0213E JIMENA
C. 01/0915Z
D. 21.5N 110.5W
E. 01/1400Z TO 01/1800Z
F. SFC TO 10,000 FT

2. SUCCEEDING DAY OUTLOOK.....NEGATIVE.
JWP

[Dean4Storms]

I thought the Low was moving slower, could it be that the UL high is moving much slower?

[Blown Away]

so we are saying its not going to hit a weakness anytime soon? Now there is a ridge building in?

What happened to the ULL that was supposed to pull it more NW?

I think that ULL is pulling 94L NW for now but I think a ridge is going to start building in and push 94L more WNW, question is how far west?

[gatorcane]

12Z GFS finally on board with good initialization and projected movement (just NE of Leewards):

[BensonTCwatcher]

The synoptic pattern , to quote the Jedi master Yoda..."future hard to see it is" with all the ULL activity. The GFS does not handle these features well as Derek has pointed out. I looked at the vorticity at all levels of the GFS and they don't look what I see on WV initially. But, it does look like if somehow the low level structure survives with a low and convection carries westward by the winds it could actually be trouble west of the islands. I don't see how this survives if it gains much latitude given that the shear is forecast to remain pretty steep near 70W.

I do see an opportunity if it rides that little pocket of low shear and gets past the shear at say 72 hrs out at 20N 75W..just a thought

http://moe.met.fsu.edu/cgi-bin/gfstc2.cgi?time=2009083106&field=850-200mb+Shear&hour=Animation

[Sanibel]

I guess the question is whether the environment will improve if it can get past the hostile shear ahead.

That didn't happen with Danny.

[cycloneye]

Latest analyisis from Dr Jeff Masters

Invest 94L
The well-organized tropical wave (94L) near 14.5N, 52W, about 500 miles east of the central Lesser Antilles Islands, continues to be a threat to develop into a tropical depression. Visible satellite imagery and this morning's QuikSCAT pass do not show a surface circulation yet, though 94L does have a large envelope of moisture and some modest heavy thunderstorm activity. QuikSCAT noted winds up to 30 mph. Water vapor satellite loops show that 94L has moistened the region surrounding it considerably, and dry air from the Saharan Air Layer is not a major impediment to development. Wind shear is a low 5 - 10 knots, and the ocean temperature are a moderately warm 28°C. Visible satellite loops over the past two hours show low-level spiral bands developing on 94L's northeast side, and I give a 70% chance the Hurricane Hunters will find a tropical depression or tropical storm on Tuesday when they investigate 94L.

The center of 94L probably passed over Buoy 41040, located at 14.5N, 53W over the past hour. Winds blew northeasterly early this morning, then went calm, then shifted to southerly late this morning. The winds were less than 10 knots during the center passage, so the circulation of 94L is not yet well-defined. The pressure fell significantly as 94L moved over the buoy (seen only after one removes the wiggles due to daily atmospheric tide effect present in the tropics). 94L will appear on Martinique radar on Tuesday.

The forecast for 94L
Shear will remain low, 5 -10 knots, over the next 5 days, SSTs will be warm, in the 28 - 29°C range, and dry air should have only a minor inhibiting effect, so I can't see anything that will prevent 94L from developing into a tropical depression over the next 1 - 2 days. The HWRF model develops 94L into a hurricane 4 days from now, as does the SHIPS intensity model, but other models, such as the GFDL, ECMWF, and GFS, do not develop 94L at all.

Model solutions for the track of 94L are divergent. Water vapor satellite loops show two upper-level lows to the north and northwest of 94L that are pulling the storm to the west-northwest, and 94L's motion is expected to range between the west-northwest and northwest over the next three days. By Tuesday, 94L will slow down from its current 15 mph forward speed to about 10 mph. Most of the models predict that the steering influence of the upper-level lows will pull 94L far enough north that the storm will miss the Lesser Antilles, with a closest approach occurring Wednesday and Thursday. However, the ECMWF and HWRF models have 94L passing within 200 miles of the islands, and the northern Lesser Antilles may experience tropical storm conditions on Thursday.

At the longer ranges, the fate of 94L is highly uncertain. The Canadian model turns 94L to the north near Bermuda, then out to sea, while the NOGAPS model foresees a threat to the U.S. East Coast early next week. Both of these solutions are believable. The Hurricane Hunters are scheduled to make their first flight into 94L on Tuesday afternoon at 2pm EDT.

[Sanibel]

CMC develops it and takes it right out to sea.

[tolakram]

seen only after one removes the wiggles due to daily atmospheric tide effect present in the tropics

Is wiggle a scientific term?

[Evil Jeremy]

Is it me, or is 94L slowing down and making more of a NW jog in the last few frames?

http://www.ssd.noaa.gov/goes/flt/t2/loop-vis.html

[Evil Jeremy]

Is it me, or is the GFS running slowly this afternoon? It has been about 45 minutes since it should of started I think, and it is only up to 42 hours.

[vacanechaser]

Is it me, or is the GFS running slowly this afternoon? It has been about 45 minutes since it should of started I think, and it is only up to 42 hours.

broken... season canceled... lol... too many people hitting it!!!



Jesse V. Bass III
http://www.vastormphoto.com
Hurricane Intercept Research Team

[gatorcane]

models are diverging at this point. Seems that the CMC and MM5 models recurve it out to sea. But the GFDL/ECMWF/NOGAPS models move it towards the SE Bahamas as a somewhat weaker entity and maybe into Florida. The difference lies partly in how strong they make 94L but how they handle the potential for a High pressure system to move off the Eastern CONUS into the Western Atlantic in the long-range. The latter models think a Bermuda High will builds while the former think that it will not. The long-term future of this invest and whether it impacts the CONUS is still uncertain. I would have to lean towards a recurve but if I did, that would be going with the percentages as most systems do recurve anyway.

[x-y-no]

Is it me, or is the GFS running slowly this afternoon? It has been about 45 minutes since it should of started I think, and it is only up to 42 hours.

I've noticed this a lot this year - in the past it would dribble out two or three frames at a time - now it seems to come in big chunks. So one winds up waiting a long time between updates.

[Sanibel]

Looks to me like the disturbance just did an intensification pulse. The elongated surface swirl to the SW just had the inner bands cut into circular conformity instead of running all the way out SW and back into the center.

The inner convection burst is slightly improving and gaining slightly better curvature. I think this is an SST influenced change that will persist. We could be seeing straight development here?


Direction is something like 285*+

[Aric Dunn]

Latest Ascat is confirming mine as well as wxman57 center fix which by the way is very broad and still tilted NE SW. but it does seem to have a closed wind field.