ATL : TROPICAL DEPRESSION ERIKA (06L)

[cycloneye]

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU AUG 27 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...

A TROPICAL WAVE IS ALONG 27W S OF 19N MOVING W NEAR 15-20 KT. A
1009 MB LOW IS EMBEDDED ON THE WAVE AXIS NEAR 11N27W. SLOW
DEVELOPMENT OF THIS SYSTEM IS POSSIBLE OVER THE NEXT COUPLE OF
DAYS. THERE IS A CHANCE OF THIS SYSTEM TO BECOME A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS. SATELLITE IMAGERY SHOWS AN
AREA OF SCATTERED MODERATE TO STRONG CONVECTION WELL W OF THE
SYSTEM FROM 8N-12N BETWEEN 31W-35W.

http://www.storm2k.org/weather/hw3.php? ... hwvmetric=

[Blown Away]

I have to agree with Derek right now this system doesn't look that impressive, sure its flaring a heap of convection but its lop-sided still, any circulation is going to have a tough time getting going in that sort of set-up.

Also BA, thats very interesting, the longer this one stays weak the less its going to feel those upper level weaknesses, somewhat like we saw with Ana FWIW.

Looks pretty good for a wave w/ a low pressure in the far eastern Atlantic. For now it seems 94L is not going to rapidly become a hurricane and will likely continue farther west.

Yep, and quite possibly like we saw with Ana, this one may not develop either. There's probably a reason that several models aren't doing much with it.

Ana did develope but struggled w/ shear and ultimately died going over PR and Hispaniola.

[KWT]

The convection is very displaced from the center, sure something could develo but it'd look very much like Danny did yesterday but with the LLC showing on the eastern side rather then western side I'd suspect.

As Derek said, keeps up this presentation and its going to have a hard time really doing much...

Saying that we will see, it probably still has a decent shot at developing IMO eventually and as you say in this set-up the weaker it stays the greater the chance it misses those upper troughs.

[Dean4Storms]

Looks to me that for a far eastern wave it seems to be well on its way to developing. Last I checked the shear was suppose to lighten up pretty much and I don't see any dry air or SAL so I would expect this to get its act together overnight and become a TD tomorrow!

[KWT]

Needs to get that deep convection probably at least a 100-150 miles closer to the developing center for the NHC to even think about upgrading it IMO, remember they are far less hasty to upgrade with a system like this generally then say a system like Danny or something closer to the US.

We shall see whether the center reforms closer to the convection, that IMO is more then possible but we shall see, in its current state and strengthening is going to be painfully slow until it gets the center much closer to the deep convection.

[Bocadude85]

Yep it is further west, still pretty far north though at 50W for it to be a real threat to the US unless a big high develops...remember between 144-192hrs there appears to be a big weakness around 60-70W which would probably lift out 94L a lot if it gets there around that time, probably enough for a total recurve if its there at that time.

Yes there is a weakness at the end of the run but your assming that the weakness will remain. A lot of the models forecast that weakness to fill in possibly forming a omega blocking pattern.
A lot of storms pass 50w near 18n and still make it all across.. a good example would be hurricane Frances

Table 1: Best track for Hurricane Frances, 25 August - 8 September 2004. Date/Time
(UTC) Position Pressure
(mb) Wind Speed
(kt) Stage
Lat.
(°N) Lon.
(°W)
25 / 0000 11.1 35.2 1009 25 tropical depression
25 / 0600 11.2 36.8 1008 30 "
25 / 1200 11.3 38.3 1007 30 "
25 / 1800 11.5 39.8 1005 35 tropical storm
26 / 0000 11.9 41.5 1003 40 "
26 / 0600 12.3 42.9 1000 45 "
26 / 1200 12.8 44.5 994 55 "
26 / 1800 13.3 45.8 987 65 hurricane
27 / 0000 13.7 46.8 984 70 "
27 / 0600 14.2 47.8 980 75 "
27 / 1200 14.7 48.5 970 90 "
27 / 1800 15.4 49.3 962 100 "
28 / 0000 15.9 50.0 962 100 "
28 / 0600 16.6 50.9 962 100 "
28 / 1200 17.2 51.6 958 105 "
28 / 1800 17.7 52.3 948 115 "
29 / 0000 18.1 52.9 948 115 "
29 / 0600 18.4 53.6 948 115 "
29 / 1200 18.6 54.4 948 115 "
29 / 1800 18.8 55.0 948 110 "
30 / 0000 18.9 55.8 954 105 "
30 / 0600 19.0 56.8 958 100 "
30 / 1200 19.2 58.1 956 100 "
30 / 1800 19.4 59.3 948 110 "
31 / 0000 19.6 60.7 946 110 "
31 / 0600 19.8 62.1 950 115 "
31 / 1200 20.0 63.5 949 120 "
31 / 1800 20.3 65.0 942 125 "
01 / 0000 20.6 66.4 941 120 "
01 / 0600 21.0 67.9 939 120 "
01 / 1200 21.4 69.1 937 120 "
01 / 1800 21.8 70.4 941 120 "
02 / 0000 22.2 71.4 939 120 "
02 / 0600 22.7 72.5 937 125 "
02 / 1200 23.2 73.5 939 120 "
02 / 1800 23.8 74.3 948 115 "
03 / 0000 24.2 75.0 948 105 "
03 / 0600 24.7 75.7 954 100 "
03 / 1200 25.3 76.3 958 95 "
03 / 1800 25.7 77.1 960 90 "
04 / 0000 26.0 77.5 960 85 "
04 / 0600 26.4 77.9 960 85 "
04 / 1200 26.8 78.5 962 90 "
04 / 1800 26.8 79.1 962 90 "
05 / 0000 27.0 79.4 958 95 "
05 / 0600 27.2 80.2 960 90

[cycloneye]

00 UTC Best Track

AL, 94, 2009082800, , BEST, 0, 102N, 300W, 25, 1009, DB

ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/ ... 009.invest

[cycloneye]

00 UTC Bam Models

WHXX01 KWBC 280028
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0028 UTC FRI AUG 28 2009

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 (AL942009) 20090828 0000 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
090828 0000 090828 1200 090829 0000 090829 1200

LAT LON LAT LON LAT LON LAT LON
BAMS 10.2N 30.0W 11.0N 32.2W 12.0N 34.6W 13.0N 37.6W
BAMD 10.2N 30.0W 10.5N 32.0W 11.1N 34.2W 12.0N 36.4W
BAMM 10.2N 30.0W 10.4N 32.5W 10.9N 34.9W 11.7N 37.5W
LBAR 10.2N 30.0W 10.5N 33.0W 11.0N 36.2W 11.7N 39.6W
SHIP 25KTS 32KTS 42KTS 53KTS
DSHP 25KTS 32KTS 42KTS 53KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
090830 0000 090831 0000 090901 0000 090902 0000

LAT LON LAT LON LAT LON LAT LON
BAMS 14.0N 40.9W 14.7N 47.3W 14.3N 51.9W 14.0N 54.5W
BAMD 13.0N 38.4W 15.0N 41.5W 16.0N 43.1W 16.6N 45.2W
BAMM 12.8N 39.9W 14.4N 44.1W 14.8N 46.5W 15.3N 48.7W
LBAR 12.7N 42.9W 14.5N 48.9W 15.0N 52.0W 16.9N 51.8W
SHIP 63KTS 79KTS 81KTS 87KTS
DSHP 63KTS 79KTS 81KTS 87KTS

...INITIAL CONDITIONS...
LATCUR = 10.2N LONCUR = 30.0W DIRCUR = 270DEG SPDCUR = 15KT
LATM12 = 10.3N LONM12 = 26.3W DIRM12 = 264DEG SPDM12 = 22KT
LATM24 = 10.9N LONM24 = 22.6W
WNDCUR = 25KT RMAXWD = 75NM WNDM12 = 25KT
CENPRS = 1009MB OUTPRS = 1011MB OUTRAD = 200NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM

[KWT]

Yeah but the block isn't going to form quickly enough if most of the models are right, for example the ECM has a weakness there in that same general area till 192hrs, if thats the case this one will be just about certain to go into that weakness.

What the models do is opening it up around 96hrs as Danny comes through, then the low you see moves away but on the front it leaves behind through the weakness a new low develops and strengthens and keeps the weakness open for at least another 48hrs, so its safe to assume that weakness would still be there more or less in the same place till at least 168hrs.

Of course plenty of systems have made it from that location...but not many with a glaring weakness progged from 60-70W that probably won't close up quickly enough for this system.

Of course what may happen is this system stays quite far south and then the weakness lifts it up but closes before the job is done...thats the biggest risk IMO right now.

[Blown Away]

Convection not that far removed from the center.

[OURAGAN]

I AGREE

[cycloneye]

Convection not that far removed from the center.

You have to fix the red circle as best track made an update of position=10.2N-30.0W

[AtlanticWind]

When you have a strong wave at the near peak of Hurricane season in this area it has to at least peak your interest, true most systems recurve but this is where many famous storms were bred!!

[KWT]

By a little over 2 degrees from the deepest convection, so probably close to 150 miles as Derek said. As Danny showed that sort of distance can be worked with but I personally don't think its that impressive.

Thats not to say I think its looks awful but its not striking me as something that is going to be upgraded in the next 12hrs put it that way.

If the convection was within half of a degree of the center then I'd be far more impressed.

However for a threat to the US, obviously the longer it takes to pull itself together the bigger the risk becomes IMO to the US east coast.

[otowntiger]

Here is the animation of this 18z GFDL run.

http://moe.met.fsu.edu/cgi-bin/gfdltc2. ... =Animation

That one looks to be real similar to Bill, if not further east. yawn.

[KWT]

Also on top of that take a look at the AVN:

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

If any center is at 30W or any developing center is there then its got pretty much no convection over it now...if thats not a sheared profile I don't know what is...

Still I wouldn't be surprised if there is some sort of MLC in that convection.

[KWT]

Saying that though its still not picking up any latitude at all and most models are strongly suggesting we should be having WNW/NW motion right now.

Whilst I think recurve is most probable I bet it gets further west then the models expect, unless this one starts to develop better then it is now.

[Bocadude85]

Yeah but the block isn't going to form quickly enough if most of the models are right, for example the ECM has a weakness there in that same general area till 192hrs, if thats the case this one will be just about certain to go into that weakness.

What the models do is opening it up around 96hrs as Danny comes through, then the low you see moves away but on the front it leaves behind through the weakness a new low develops and strengthens and keeps the weakness open for at least another 48hrs, so its safe to assume that weakness would still be there more or less in the same place till at least 168hrs.

Of course plenty of systems have made it from that location...but not many with a glaring weakness progged from 60-70W that probably won't close up quickly enough for this system.

Of course what may happen is this system stays quite far south and then the weakness lifts it up but closes before the job is done...thats the biggest risk IMO right now.

Looking at the 12z Euro I see a weakness between 70-80 west and this system is still at 55w at 168hours
http://www.meteo.psu.edu/~gadomski/ECMWFTROPATL_12z/f168.gif which in my opinion would be enough time for the weakness to fill and allow the system to continue west to wnw

[AtlanticWind]

Also on top of that take a look at the AVN:

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

If any center is at 30W or any developing center is there then its got pretty much no convection over it now...if thats not a sheared profile I don't know what is...

Still I wouldn't be surprised if there is some sort of MLC in that convection.

This has many days to develop , large systems in the east atlantic often take their time,still a strong disturbance at this point.

[Ivanhater]

GFS Ensembles