ATL: TROPICAL LOW ex-FRED (ex-07L)

[Derek Ortt]

not sure what is going on the the GFDL model... but something is wrong witht he initialization. The GFS has a strong vortex, but no initial vortex for the GFDL

[artist]

Anyone has the 12z model package,GFS,GFDL,HWRF,NOGAPS,UKMET,CMC,Bams,ECMWF? I ask because I am without my PC for today as the keyboard is being repaired and I dont have links as I am on another PC.

http://www.meteo.psu.edu/~gadomski/ewall.html

I think this covers most of them for you cycloeye. Enjoy your day!

[jinftl]

Update from Dr. Jeff Masters late this morning:

A tropical wave (96L) that emerged off the coast of Africa yesterday has organized rather quickly, and will likely become a tropical depression by Tuesday night. Satellite imagery from the European satellite shows a well-organized circulation, but not enough heavy thunderstorm activity near the center of circulation to be considered a tropical depression. The storm is far enough south that the dry air of the Saharan Air Layer is not a major impediment to development. Wind shear is moderate, 10 - 15 knots, and ocean temperatures are 1 - 2°C above the threshold needed for tropical cyclone formation.

Most of the models develop 96L, and the chances are that this disturbance will become Tropical Storm Fred later this week. The system will initially move west-northwest, but by Thursday, a strong trough of low pressure passing to 96L's north will pull the storm to the northwest, and may be capable of fully recurving the storm to the northeast. However, most of the models foresee that 96L will not move far enough north for this to happen, and that the storm will have to wait for the next trough of low pressure. With the steering pattern for this year continuing to feature plenty of deep troughs of low pressure moving off the U.S. East Coast, the odds of 96L making it all the way across the Atlantic to threaten land areas appear low. Still, much that is unexpected can and does happen in the world of tropical meteorology, and 96L bears watching.

[senorpepr]

AL, 96, 2009090718, , BEST, 0, 124N, 239W, 25, 1007, DB, 0, , 0, 0, 0, 0,

[senorpepr]

^^ Also of note. When the 06Z position was updated to increase the winds to 30 kt and drop the pressure to 1005 hPa. Conditions returned to 25 kt and 1007 hPa, respectively, at 12Z.

[jinftl]

Indicative of weakening or just changing estimates of an evolving system? I tend to think it is due to the estimates, the outlook for this system developing is still very bullish.

NHC Tropical Weather Discussion this afternoon mentions a 1008 mb system....at 11.5N...almost a full degree south of most estimates.

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN SEP 06 2009

...SPECIAL FEATURE...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 21W/22W TO THE SOUTH OF
20N MOVING WEST ABOUT 15 KT. A 1008 MB LOW PRESSURE CENTER IS
ALONG THE WAVE NEAR 11.5N. STRONG SHOWERS AND THUNDERSTORMS ARE
FROM 11.5N TO 13N BETWEEN 14W AND 16W. OTHER SHOWERS AND
THUNDERSTORMS COVER THE AREA FROM 10N TO 15N BETWEEN 23W AND 26W.
ITCZ PRECIPITATION IS TO THE SOUTH OF THE WAVE. THE CHANCE THAT
THIS SYSTEM MAY BECOME A TROPICAL CYCLONE DURING THE NEXT
48 HOURS IS HIGH.

^^ Also of note. When the 06Z position was updated to increase the winds to 30 kt and drop the pressure to 1005 hPa. Conditions returned to 25 kt and 1007 hPa, respectively, at 12Z.

[CrazyC83]

If only they could fly Recon out of Cape Verde to prove things for us...

[lester]

If only they could fly Recon out of Cape Verde to prove things for us...

prove what? that it's a 25-30 kt storm?

[cycloneye]

I found the link to dvorak at the first pages of thread

07/1745 UTC 12.3N 23.5W T1.5/1.5 96L -- Atlantic

http://www.ssd.noaa.gov/PS/TROP/tdpositions.html

[jinftl]

Get what you mean from a data standpoint, but the reality is that if a recon was flown to check out this system given the limited funds available and the cost of each flight, heads would...and should... roll. Fortunately, the point is moot given the logistics of from where and when recon flights are made.

Whether we are talking an invest at 12.3N or 11.5N, with a pressure of 1005 mb or 1007 mb, and winds of 20 or 25 mph isn't material. A developing system doesn't have a clear center by definition. The winds and rain are most likely in scattered convection, not an organized mass yet. Gusty squally whether may effect parts of the Cape Verde Islands, but estimates from satellites and ships are more than sufficient to prepare forecasts and alert folks.

If only they could fly Recon out of Cape Verde to prove things for us...

[RL3AO]

BEGIN
NHC_ATCF
invest_RENUMBER_al962009_al072009.ren
FSTDA
R
U
040
010
0000
200909071913
NONE
NOTIFY=ATRP
END

[cycloneye]

We have TD 7.

TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1918 UTC MON SEP 7 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

TROPICAL CYCLONE SEVEN (AL072009) 20090907 1800 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
090907 1800 090908 0600 090908 1800 090909 0600

LAT LON LAT LON LAT LON LAT LON
BAMS 12.4N 23.9W 13.0N 26.8W 13.7N 30.3W 14.1N 34.0W
BAMD 12.4N 23.9W 12.9N 26.5W 13.7N 28.9W 14.7N 31.1W
BAMM 12.4N 23.9W 13.0N 26.5W 13.8N 29.2W 14.7N 31.9W
LBAR 12.4N 23.9W 12.8N 26.5W 13.6N 29.3W 14.4N 31.9W
SHIP 30KTS 35KTS 42KTS 50KTS
DSHP 30KTS 35KTS 42KTS 50KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
090909 1800 090910 1800 090911 1800 090912 1800

LAT LON LAT LON LAT LON LAT LON
BAMS 14.3N 37.3W 14.3N 40.2W 13.3N 38.6W 12.0N 36.1W
BAMD 15.9N 33.2W 19.2N 35.9W 22.4N 35.8W 24.6N 36.0W
BAMM 15.6N 34.4W 17.6N 37.3W 18.8N 37.4W 19.6N 37.2W
LBAR 15.4N 34.3W 17.9N 37.0W 22.5N 37.5W 26.4N 36.9W
SHIP 55KTS 63KTS 58KTS 48KTS
DSHP 55KTS 63KTS 58KTS 48KTS

...INITIAL CONDITIONS...
LATCUR = 12.4N LONCUR = 23.9W DIRCUR = 280DEG SPDCUR = 15KT
LATM12 = 11.9N LONM12 = 20.9W DIRM12 = 277DEG SPDM12 = 13KT
LATM24 = 11.8N LONM24 = 17.8W
WNDCUR = 30KT RMAXWD = 60NM WNDM12 = 30KT
CENPRS = 1005MB OUTPRS = 1009MB OUTRAD = 170NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM

[somethingfunny]

Get what you mean from a data standpoint, but the reality is that if a recon was flown to check out this system given the limited funds available and the cost of each flight, heads would...and should... roll. Fortunately, the point is moot given the logistics of from where and when recon flights are made.

Whether we are talking an invest at 12.3N or 11.5N, with a pressure of 1005 mb or 1007 mb, and winds of 20 or 25 mph isn't material. A developing system doesn't have a clear center by definition. The winds and rain are most likely in scattered convection, not an organized mass yet. Gusty squally whether may effect parts of the Cape Verde Islands, but estimates from satellites and ships are more than sufficient to prepare forecasts and alert folks.

If only they could fly Recon out of Cape Verde to prove things for us...

Speaking of rolling heads, were the repeated flights of Danny and Erika to determine if sustained winds in their highly sheared convective masses were still at TS force....excusing the run on sentence, were those flights any more necessary? I'd think make one flight to get a handle of what you're dealing with, and then let that guide the satelite obs and estimates. Send another flight out if something significant changes and it becomes more threatening.


Back on topic, it looks like we'll have 07L here shortly.

[HURAKAN]

NRL: 07L

Looking very good

[jinftl]

Looking better and better....nice outflow....cirrus fanning that you see in developing systems in a conducive environment.

[RL3AO]

Where can you find this information

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

[jinftl]

Update to 18z coordinates data on wunderground shows pressure of 1005 mb and wind up to 30 mph....this is on it's way

Time Lat Lon Wind(mph) Pressure Storm type
-------------------------------------------------------------
18 GMT 09/6/09 12.5N 18.0W 25 1007 Invest
18 GMT 09/7/09 12.5N 18.0W 25 1007 Invest
00 GMT 09/7/09 12.6N 19.6W 25 1007 Invest
12 GMT 09/7/09 12.0N 21.9W 25 1007 Invest
18 GMT 09/7/09 12.4N 23.9W 25 1005 Invest
18 GMT 09/7/09 12.4N 23.9W 30 1005 Invest

[senorpepr]

Yup, 18Z best track has it at a 30 kt 1005 hPa depression.

[cycloneye]

Another sign that it will be upgraded at 5 PM is that the automated graphic at the top of forum doesnt have invest 96L anymore as it will update with TD 7 after the advisory is out.

[wxman57]

Great! Pure fish storm. That's the kind everyone here likes to track. Should get a lot of chatter here on the forum now, debating back and forth as to whether it recurves at 33W or 38W. I imagine this thread will top 100 pages in a few days.