ATL : TROPICAL DEPRESSION ERIKA (06L)

[tolakram]

I don't see this dodging the shear. Perhaps that's what the models are seeing.

[cycloneye]

SHIP still likes 94L. A tad slower down from 19kts to 17kts.

182
WHXX01 KWBC 291236
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1236 UTC SAT AUG 29 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) 20090829 1200 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
090829 1200 090830 0000 090830 1200 090831 0000

LAT LON LAT LON LAT LON LAT LON
BAMS 11.1N 41.2W 12.5N 43.3W 13.6N 45.8W 14.7N 48.3W
BAMD 11.1N 41.2W 11.9N 43.9W 13.0N 46.5W 14.1N 48.6W
BAMM 11.1N 41.2W 12.1N 43.8W 13.0N 46.3W 14.0N 48.6W
LBAR 11.1N 41.2W 11.8N 44.2W 12.8N 47.3W 13.8N 50.1W
SHIP 25KTS 30KTS 36KTS 45KTS
DSHP 25KTS 30KTS 36KTS 45KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
090831 1200 090901 1200 090902 1200 090903 1200

LAT LON LAT LON LAT LON LAT LON
BAMS 15.3N 50.8W 16.3N 54.9W 17.3N 57.3W 18.4N 59.5W
BAMD 14.9N 50.4W 15.9N 53.3W 16.8N 55.8W 18.3N 58.0W
BAMM 14.6N 50.5W 15.2N 53.8W 15.7N 56.3W 16.4N 58.7W
LBAR 14.8N 52.8W 16.3N 56.8W 16.8N 59.1W 17.6N 60.5W
SHIP 50KTS 68KTS 81KTS 85KTS
DSHP 50KTS 68KTS 81KTS 85KTS

...INITIAL CONDITIONS...
LATCUR = 11.1N LONCUR = 41.2W DIRCUR = 270DEG SPDCUR = 17KT
LATM12 = 11.2N LONM12 = 38.1W DIRM12 = 272DEG SPDM12 = 19KT
LATM24 = 10.7N LONM24 = 34.0W
WNDCUR = 25KT RMAXWD = 75NM WNDM12 = 25KT
CENPRS = 1010MB OUTPRS = 1012MB OUTRAD = 170NM SDEPTH = S
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM

[cycloneye]

12 UTC Best Track

AL, 94, 2009082912, , BEST, 0, 111N, 412W, 25, 1010, DB

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

[Derek Ortt]

Man i hate El Nino years Easterlies are winning the war this year. Seems Bill just got lucky being at the right place at the right time. This season might just wrap up early.

please explain how el nino causes easterlies. This is something that does not match the accepted theory at all and I'd like to be enlightened

[wxman57]

This is what I see with 94L (below). There's a wave axis and a broad surface circulation located east of where the NHC initialized the models. Don't see anything out at 41W any more. That was just a transient vorticity max. The low is free of any significant convection. And lacking convection, it will have a hard time developing.

If it continues moving westward without developing, then it'll probably die when it reaches the Caribbean. If it develops, then it could pose a threat to the NE Caribbean, or it might pass north of the Caribbean. Most likely, it won't develop and it will move across the Caribbean late next week as a convectionless wave.

[otowntiger]

I have to disagree with you wxman57. I think this thing will absolutely vanish before it ever gets to the islands. It won't even be a convectionless wave. It will only be a memory.

[gatorcane]

I'd say there is a decent chance by tomorrow its back to code yellow, with diminished convection as the reason. It's not looking well tonight. Despite the pretty good conditions it just doesn't seem to be getting its act together. There is also alot of dry air out to the west it will start bumping into.

Obviously given the time of year its something to watch but right now nothing to get concerned about.

Tonight there has been convection developing on the SE side of 94L, which means the E shear is easing a bit.
The center is still very broad but we are seeing the convection starting to tighten up. Over the past few hours there has been more of a cyclonic rotation and maybe a very slight N component.

Well I know my call that it was going to get downgraded (my call from last night) and that I was not worried about this area didn't make sense yesterday but anyway.....

I have to agree with Wxman, likely a wave passing through the Caribbean....time to look elsewhere.

[Derek Ortt]

looks like I wont need that dunce cap

[HURAKAN]

An interesting system to study. It's always puzzling why a system with favorable conditions to develop doesn't.

[wxman57]

An interesting system to study. It's always puzzling why a system with favorable conditions to develop doesn't.

If it doesn't develop, then conditions weren't favorable. There's an inhibitor you/we aren't seeing if we think conditions are favorable. A big problem out in the tropics is a lack of good data at the surface and aloft. Models are initiated with data, but is it good, reliable data? Probably not in many cases.

[cycloneye]

My opinion as a hurricane follower for more than 40 years is that even in the peak weeks of the season,if there is El Nino around,even if is a weak one,the Atlantic turns to negative conditions as we haved seen this year.

[Blown Away]

Convection building a little, maybe 94L's last breath!

[Derek Ortt]

An interesting system to study. It's always puzzling why a system with favorable conditions to develop doesn't.

because conditions were downright hostile. Mid level shear is far more destructive than upper shear and this had high mid level easterly shear

[otowntiger]

An interesting system to study. It's always puzzling why a system with favorable conditions to develop doesn't.

If it doesn't develop, then conditions weren't favorable. There's an inhibitor you/we aren't seeing if we think conditions are favorable. A big problem out in the tropics is a lack of good data at the surface and aloft. Models are initiated with data, but is it good, reliable data? Probably not in many cases.

That's why when I comment on this particular subject I aways say "seemingly" favorable conditions. Because as you say something not apparent to us inhibited development. We've got a long ways to go in this field don't we? I think the NHC has pretty well conquered storm tracks but has made no progress on predicting intensity and/or development potential.

[Gustywind]

Latest from Meteo-France 9am:

[lonelymike]

looks like I wont need that dunce cap

Live you #@%&^% live

[capepoint]

4 letter word...starts with P and ends with F....May I buy an O please?

[Derek Ortt]

An interesting system to study. It's always puzzling why a system with favorable conditions to develop doesn't.

If it doesn't develop, then conditions weren't favorable. There's an inhibitor you/we aren't seeing if we think conditions are favorable. A big problem out in the tropics is a lack of good data at the surface and aloft. Models are initiated with data, but is it good, reliable data? Probably not in many cases.

That's why when I comment on this particular subject I aways say "seemingly" favorable conditions. Because as you say something not apparent to us inhibited development. We've got a long ways to go in this field don't we? I think the NHC has pretty well conquered storm tracks but has made no progress on predicting intensity and/or development potential.

some of it is forecaster error. Too much focus is placed on SST and upper winds. That may explain about 30 percent of what goes into formation. You also have mid level winds, low level convergence, moisture, lapse rate, etc

[Sanibel]

Bust. No tightening last night. Only satellite illusion.

2009 continues to have good wave presentation followed by a negative subsidence-like atmospheric that dries out storms.

This one could still form further west but the dry air ahead could kill it like Ana.


Our African land-cane could suffer the same fate. Maybe we need another MJO before anything will form.

[gatorcane]

Snippet from NWS Miami. They use the word "trough" several times (four times to be precise) in this extended forecast snippet. Pattern is like a late Fall pattern out there as far as troughs are concerned, with the heat of summer. The troughs have been strong all summer and even last winter which brought low to mid 30s way down into Southern FL a few times (very rare). Even if 94L develops and attempts get past 60W say north of the islands....there are alot of troughs ahead.

I may start looking in the Caribbean now, this pattern so long as it lasts will not bring Cape Verde systems into the CONUS.

THE EASTERN U.S. TROUGH AMPLIFIES AGAIN BY THE MIDDLE PART OF NEXT
WEEK. MEANWHILE...AN INVERTED TROUGH MOVES INTO THE AREA FROM THE
EAST LATE TUE/WED. THE MID/UPPER TROUGH ACROSS THE EAST REMAINS
NEARLY STATIONARY WITH A SURFACE FRONTAL TROUGH FORMING OFF THE
EASTERN SEABOARD SOUTHWESTWARD INTO FLORIDA. GFS/ECMWF BOTH SHOW
THIS SIGNAL...SO INCREASED POPS A BIT FOR THE MIDDLE PART OF NEXT
WEEK. STILL...NO "SIGNIFICANT" WEATHER FEATURES ARE LOOMING AT THIS
TIME.

http://forecast.weather.gov/product.php ... glossary=1