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

[Aric Dunn]

All the data I've looked at shows this very close if not a depression. Lets see if more convection can keep flaring up, then we should have a cyclone.

.
sounds good

I'm going to bed LOL im seeing double

[Cyclenall]

Does anyone else get the feeling they won't get much sleep tonight?

[Brent]

Does anyone else get the feeling they won't get much sleep tonight?

Does anyone feel they won't get much sleep for the next 10 days?

[marcane_1973]

I think we are going to see a center fix more toward the north than everyone thought. On the latest satellite you can see the deep reds there. Just wondering if that is where the center is starting to form now??? If the center is in fact locating more to the north then I would think the models would shift more to the North in time. Guess we will know more about that later on this morning. If indeed the center does relocate more to the north this could end up being bad news later on down the road for the SE from Florida to the Carolinas instead of a coarse that runs through the Caribbean and GOM. I know it is still very early in that ballgame. Thoughts on that anyone??? Here is a nice satellite photo of our invest. http://oiswww.eumetsat.org/SDDI/cgi/lis ... v=400,pp=0

[weatherman21]

From looking at the 6Z MeteoSat IR, I notice the wave is maintaining deep convection within its parameters and this has been the general case since it departed from the west coast of Africa about 36 hours ago or so. IR imagery shows a well organized wave with fairly established banding features. The wave appears to be tracking westward and is now just south of the Cape Verde Islands. I see no dry air nor shear affecting the wave and sea surface temps appear to be averaging 80 degrees F. Once the wave begins to be picked up by the GOES Satellite, I can get a better analysis as my access to the MeteoSat in the IDV is limited to every 6 hours.
Only time will tell as to how well the results will be of the performance of the GFS model. Up to this point, the GFS appears to have performed well in forecasting the wave to emerge off the west African coast and then a gradual increase in strength occuring thereafter. The timing of the wave to depart from the west African coast was predicted fairly well by the GFS model.
Once question, Is it true that the models have a more difficult time handleing cyclones once they begin to come closer to land masses, such as the United States and Mexico as opposed to when they are over the open Atlantic?

MeteoSat IR at 6Z:


Global GFS Run from 0Z; Forecast for 15Z on Wednesday, 8/15:


Global GFS Run from 0Z; Forecast for 9Z on Friday, 8/17:

[Chacor]

000
ABNT20 KNHC 120912
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
530 AM EDT SUN AUG 12 2007

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

A BROAD AREA OF LOW PRESSURE OVER THE WESTERN CARIBBEAN SEA IS
PRODUCING DISORGANIZED SHOWERS AND THUNDERSTORMS NEAR JAMAICA...THE
CAYMAN ISLANDS...AND CUBA. DEVELOPMENT OF THIS SYSTEM...IF
ANY...IS EXPECTED TO BE SLOW TO OCCUR AT IT MOVES WESTWARD INTO THE
YUCATAN PENINSULA AT ABOUT 10 MPH.

A VIGOROUS TROPICAL WAVE IS LOCATED OVER THE FAR EASTERN ATLANTIC
OCEAN ABOUT 300 MILES SOUTH-SOUTHEAST OF THE SOUTHERNMOST CAPE VERDE
ISLANDS. CONDITIONS APPEAR FAVORABLE FOR GRADUAL DEVELOPMENT OF
THIS SYSTEM...AND A TROPICAL DEPRESSION COULD FORM DURING THE NEXT
DAY OR TWO AS IT MOVES WESTWARD AT 15 TO 20 MPH.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER RHOME

[punkyg]

Noooooooooooooooooooooooooooooooooo!

[Normandy]

It looks much much better right now then it did 2 hours ago....I would venture to say that the center is now under the convection with some slight confidence, and it looks like it has consolidated.
http://oiswww.eumetsat.org/SDDI/cgi/lis ... v=400,pp=0

The good thing is:
Our wait for TD4 might be over....I can't see the NHC going through tomorrow without classifying this.

The bad thing is:
The islands could take it on the chin.....hard.

[tropicsPR]

First Visible:

[P.K.]

WONT50 LFPW 120747

A
SECURITE ON METAREA 2, METEO-FRANCE,

WARNING NR 385 , SUNDAY 12 AUGUST 2007 AT 0740 UTC

GENERAL SYNOPSIS, SUNDAY 12 AT 0000 UTC
NEW LOW EXPECTED 996 45N46W BY 12/12 UTC, MOVING NORTHEAST AND
DEEPENING, EXPECTED 990 47N40W BY 13/00 UTC, THEN 987 49N34W BY
13/12 UTC.
VIGOROUS TROPICAL WAVE ALONG 25W SOUTH OF 20N, WITH LOW 1006 NEAR
12N25W BY 12/06 UTC, MOVING WEST AT 15KT.

SIERRA LEONE
CONTINUING TO 13/12UTC AT LEAST.
CYCLONIC 8. SEVERE OR VIOLENT GUSTS. NUMEROUS STRONG THUNDERSQUALLS.

FARADAY
FROM 13/00 UTC TO 14/00 UTC AT LEAST.
SOUTHERLY 8, VEERING WESTERLY 8 OR 9, 10 AT TIMES IN NORTH. SEVERE
GUSTS. SEA BECOMING HIGH.

ALTAIR
FROM 13/03 UTC TO 13/15 UTC
IN NORTH: WEST OR SOUTHWEST 8. SEVERE GUSTS.=

[TSmith274]

This thing has got to be a depression. I'll be shocked if it doesn't achieve status at some point today.

[punkyg]

First Visible:

Hmmm it don't look bad.

[Vortex]

8/12 6z GFS rolling in..

Hour 102

http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_102l.gif

[WindRunner]

A quick run-through of the models on this system (or at least how they appeared at 00z before I left this morning) . . . even though 00z models have probably already been discussed already . . .


ECMWF is starting to realize that this is not the perfect situation . . . and is now adjusting its forecast accordingly. While both the GFS and CMC take this into the northern Caribbean at <1000mb around the day 6/7 time frame, the Euro instead opts for a weaker and more northerly track to a couple hundred miles NW of the Turks and Caicos by day 8. Upon further inspection of the GFS, the Euro seems to be a more sane option at this point. The GFS has an upper low drop southward just behind the cyclone as it passes 40W, and the trough coming off the East Coast now just misses the cyclone to the east about a day later . . . two awfully close (and awfully lucky) occurances. And of course if the negative upper level features are completely avoided, the environment is otherwise favorable . . . leading the GFS to really go wild with this system before it hits the islands. For example, the HWRF (based off the GFS) has a TS at 12z today, a hurricane by 06z Wednesday morning, and starts bombing it out beyond 114 hours (MSLP 960mb/100kts) through the end of the run at 126 hours (MSLP 948mb/110kts), at which point it is slightly northeast of the corresponding GFS position. Needless to say, as much as I'm sure some people would love to see it happen, the GFS and all related solution seem somewhat unreliable at this point . . . and until the storm gets going, similar idealized scenarios will be both commonplace and wrong.


Key feature to watch: Ridge over the southeast in the day 7-10 range (and associated weakness to the east) as that will be our main steering feature once it nears land.

[wjs3]

A quick run-through of the models on this system (or at least how they appeared at 00z before I left this morning) . . . even though 00z models have probably already been discussed already . . .


ECMWF is starting to realize that this is not the perfect situation . . . and is now adjusting its forecast accordingly. While both the GFS and CMC take this into the northern Caribbean at <1000mb around the day 6/7 time frame, the Euro instead opts for a weaker and more northerly track to a couple hundred miles NW of the Turks and Caicos by day 8. Upon further inspection of the GFS, the Euro seems to be a more sane option at this point. The GFS has an upper low drop southward just behind the cyclone as it passes 40W, and the trough coming off the East Coast now just misses the cyclone to the east about a day later . . . two awfully close (and awfully lucky) occurances. And of course if the negative upper level features are completely avoided, the environment is otherwise favorable . . . leading the GFS to really go wild with this system before it hits the islands. For example, the HWRF (based off the GFS) has a TS at 12z today, a hurricane by 06z Wednesday morning, and starts bombing it out beyond 114 hours (MSLP 960mb/100kts) through the end of the run at 126 hours (MSLP 948mb/110kts), at which point it is slightly northeast of the corresponding GFS position. Needless to say, as much as I'm sure some people would love to see it happen, the GFS and all related solution seem somewhat unreliable at this point . . . and until the storm gets going, similar idealized scenarios will be both commonplace and wrong.


Key feature to watch: Ridge over the southeast in the day 7-10 range (and associated weakness to the east) as that will be our main steering feature once it nears land.

This is an excellent and thoughtful piece of analysis. Thanks for taking the time to do it. I haven't compared the GFS and Euro runs yet, but will now.

WJS3

[Vortex]

GFS 6Z H-114 approaching islands

http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_114l.gif

[Vortex]

H-126 6Z Landfalling Hurricane near Guadeloupe



http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_126l.gif

[Vortex]

H-144 6Z South o Puerto Rico


http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_144l.gif

[wjs3]

A quick run-through of the models on this system (or at least how they appeared at 00z before I left this morning) . . . even though 00z models have probably already been discussed already . . .


ECMWF is starting to realize that this is not the perfect situation . . . and is now adjusting its forecast accordingly. While both the GFS and CMC take this into the northern Caribbean at <1000mb around the day 6/7 time frame, the Euro instead opts for a weaker and more northerly track to a couple hundred miles NW of the Turks and Caicos by day 8. Upon further inspection of the GFS, the Euro seems to be a more sane option at this point. The GFS has an upper low drop southward just behind the cyclone as it passes 40W, and the trough coming off the East Coast now just misses the cyclone to the east about a day later . . . two awfully close (and awfully lucky) occurances. And of course if the negative upper level features are completely avoided, the environment is otherwise favorable . . . leading the GFS to really go wild with this system before it hits the islands. For example, the HWRF (based off the GFS) has a TS at 12z today, a hurricane by 06z Wednesday morning, and starts bombing it out beyond 114 hours (MSLP 960mb/100kts) through the end of the run at 126 hours (MSLP 948mb/110kts), at which point it is slightly northeast of the corresponding GFS position. Needless to say, as much as I'm sure some people would love to see it happen, the GFS and all related solution seem somewhat unreliable at this point . . . and until the storm gets going, similar idealized scenarios will be both commonplace and wrong.


Key feature to watch: Ridge over the southeast in the day 7-10 range (and associated weakness to the east) as that will be our main steering feature once it nears land.

OK, in a quick look at these two, I woud argue that the GFS even places the upper low in a perfect spot for intensification--it sits right where it needs to in order to provide an outflow channel for the system in the mid-atlantic. I used the Penn State e-wall for the euro and it did not seem to see that upper low (hard to tell becasue the 4 panels really aren't helpful there). As such, the aggressive outflow did not exist, and the system seemed weaker.

The GFS seems to have it miss the trough because the GFS is faster than the Euro with the system--the system is west of (and a bit south of) where it needs to be for the trough to get it in the GFS. So I think there's a forward speed issue at play too.

WJS3

[Vortex]

Buoy has wind shift to the ssw..notice the approach had N winds and with its passage the wind shift. There's def an LLC



Air Temperature (ATMP): 78.8 °F
Water Temperature (WTMP): 81.0 °F
Atmospheric Pressure (PRES): 29.84 in
Wind Speed (WSPD): 14.0 kts
Wind Direction (WDIR): SSW (210 deg)








Station 13001 - NE Extension

Owned and maintained by the PIRATA (Pilot Research Moored Array in the Tropical Atlantic) Project
Atlas Buoy
12 N 23 W (12°0'0" N 23°0'0" W)

Anemometer height: 4 m above site elevation


Meteorological Observations from Nearby Stations and Ships

Latest Satellite Wind Map for this Area


08 12 0400 11.45 -22.99 WNW 8 - 29.83 - 77.5 81.1
08 12 0300 11.45 -22.99 NW 13 - 29.83 - 77.7 81.1
08 12 0200 11.45 -22.99 NW 10 - 29.86 - 77.7 81.1
08 11 2200 11.45 -22.99 NNW 9 - 29.87 - 79.7 81.1
08 11 2100 11.45 -22.99 NNW 10 - 29.85 - 79.5 81.1
08 11 1900 11.43 -22.97 NNW 12 - 29.81 - 80.4 81.3
08 11 1600 11.44 -22.99 N 11 - 29.83 - 80.2 81.3
08 11 1300 11.45 -22.99 N 11 - 29.87 - 80.4 81.3
08 11 1000 11.45 -22.99 N 9 - 29.88 - 80.2 81.1
08 11 0900 11.45 -22.99 N 10 - 29.87 - 80.4 81.1
08 11 0800 11.45 -22.99 N 13 - 29.84 - 80.4 81.3
08 11 0400 11.45 -22.99 N 12 - 29.84 - 79.7 81.3
08 11 0300 11.45 -22.99 N 13 - 29.85 - 79.9 81.3
08 11 0200 11.45 -22.99 N 13 - 29.88 - 79.9 81