ATL : TROPICAL DEPRESSION ERIKA (06L)

[cycloneye]

12 UTC Bam Models

157
WHXX01 KWBC 311212
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1212 UTC MON AUG 31 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) 20090831 1200 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
090831 1200 090901 0000 090901 1200 090902 0000

LAT LON LAT LON LAT LON LAT LON
BAMS 15.0N 52.1W 16.4N 54.6W 17.4N 56.7W 18.3N 58.3W
BAMD 15.0N 52.1W 16.3N 54.2W 17.4N 56.0W 18.2N 57.3W
BAMM 15.0N 52.1W 16.0N 54.3W 16.8N 56.1W 17.3N 57.5W
LBAR 15.0N 52.1W 16.6N 54.1W 17.6N 56.1W 18.2N 57.8W
SHIP 25KTS 28KTS 34KTS 43KTS
DSHP 25KTS 28KTS 34KTS 43KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
090902 1200 090903 1200 090904 1200 090905 1200

LAT LON LAT LON LAT LON LAT LON
BAMS 18.8N 60.0W 20.0N 62.7W 21.0N 66.1W 21.9N 70.1W
BAMD 18.6N 58.5W 19.4N 60.7W 20.0N 62.8W 20.0N 65.0W
BAMM 17.6N 58.9W 17.9N 61.1W 18.0N 63.7W 18.0N 67.1W
LBAR 18.6N 59.7W 18.7N 63.1W 19.4N 66.5W 19.8N 69.1W
SHIP 53KTS 67KTS 71KTS 71KTS
DSHP 53KTS 67KTS 71KTS 58KTS

...INITIAL CONDITIONS...
LATCUR = 15.0N LONCUR = 52.1W DIRCUR = 305DEG SPDCUR = 14KT
LATM12 = 13.5N LONM12 = 49.9W DIRM12 = 306DEG SPDM12 = 14KT
LATM24 = 12.0N LONM24 = 47.1W
WNDCUR = 25KT RMAXWD = 60NM WNDM12 = 25KT
CENPRS = 1008MB OUTPRS = 1010MB OUTRAD = 180NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM

[Gustywind]

Dr. Jeff Masters' WunderBlog
http://www.wunderground.com/blog/JeffMa ... rynum=1301

Last Updated: 07:50 GMT le 31 août 2009

Invest 94L Invest 94L is still out there, moving westwards to the Lower Antilles. People in the Lesser Antilles still need to keep an eye on this storm, as tropical storm formation is possible with this storm. This is still considerable uncertainty on the track of this feature as different models have different initializations of the storm. However, the Plan of the Day indicates that reconnaissance missions into Invest 94L could start as soon as Tuesday, September 1, which would give everybody more data to understand what's going on.

[Gustywind]

[KWT]

Very interesting, you can see the bend back west on quite a few models...of course it'll be interesting to see if shear is a big issue, esp as the models have ben awful this year for that problem.

['CaneFreak]

looks like good westerly shear has got to this this morning. Check the inflow bands. The center looks at the western edge or west of the convection

Kudos on your north-ward shift of the circulation call last night...

[Evil Jeremy]

A decent swing to the south and west with the 06z models and new BAM.

[KWT]

looks like good westerly shear has got to this this morning. Check the inflow bands. The center looks at the western edge or west of the convection

Very interesting, would make sense as well given the presentation, I think shear is going to be a big issue for this system pretty soon looking at the shear maps, huge shear to the north of it, though much depends on whether the ULL keeps moving westwards...won't get out of this shear though till about 65W it seems.

[Frank2]

I still think the models should have a built-in shear bias since all have been struggling to forecast around El Nino shear...

Good morning to all...

[KWT]

Its nothing to do with el Nino Frank, heck I remember with Hurricane Karen quite a few models totally missed the shear which killed it and that was in a year with a borderline La Nina...in fact that happened several times.

The models just need to get some sort of better way of forecasting upper level winds as they have been pretty poor this year.

[Derek Ortt]

035
WHXX04 KWBC 311113
CHGQLM
ATTENTION...NATIONAL HURRICANE CENTER

NCEP COUPLED GFDL HURRICANE MODEL FORECAST MADE FOR

TROPICAL DEPRESSION INVEST 94L

INITIAL TIME 6Z AUG 31

DISCLAIMER ... THIS INFORMATION IS PROVIDED AS GUIDANCE. IT
REQUIRES INTERPRETATION BY HURRICANE SPECIALISTS AND SHOULD
NOT BE CONSIDERED AS A FINAL PRODUCT. PLEASE SEE THE TPC/NHC
OFFICIAL FORECAST.


FORECAST STORM POSITION

HOUR LATITUDE LONGITUDE HEADING/SPEED(KT)

0 13.4 50.9 290./13.0

STORM DISSIPATED AT 0 HRS AT THE ABOVE PSN.

it's called the GFS has such an awful depiction, that the bogus GFDL vortex cannot even provide a vortex when it is blended into the environmental flow

[x-y-no]

Still early days, but with this northward relocation I have to favor a recurve prior to Florida, although the ECMWF does take it into the southeast Bahamas on day 7 with at least some mid-level ridging over it.

HPC keeps a stationary front off the EC throughout the week - which would seem to indicate a fair chance of keeping this offshore.

[tolakram]

Not very many frames yet, but here is the closeup loop:

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

from: http://rammb.cira.colostate.edu/product ... r=AL942009


There is a brick wall in front of it.
Shear Tendency map


from: http://cimss.ssec.wisc.edu/tropic/real- ... g8sht.html

[KWT]

Still early days, but with this northward relocation I have to favor a recurve prior to Florida, although the ECMWF does take it into the southeast Bahamas on day 7 with at least some mid-level ridging over it.

HPC keeps a stationary front off the EC throughout the week - which would seem to indicate a fair chance of keeping this offshore.

The HPC is probably based alot from the GFS but that model has rather overdone eastern troughs so far in the last 10 days, so has the CMC which is interesting given those aren't showing much of a high coming off the US, whilst the ECM has it upto 1030mbs, big differences!

Yep shows the shear is pretty high to its west, this system is going to struggle in the next few days despite its presentation right now.

[Weatherboy1]

hard to believe they'll let this go past 11 a.m. without calling it. Clearly a TD now, in my opinion.

[cycloneye]

West jog.

[wxman57]

Satellite appearances can be deceiving, particularly if you're using an infrared loop. To determine organization and movement, you need to look at a high-res visible loop. Fortunately, 94L is passing a buoy, and there are several observations around the area. The buoy's pressure has risen 1.5mb in the past few hours as 94L approached. Take a look at the wind field indicated by the obs throughout 94L. Crosshairs mark the NHC 12Z position. Still think it should be upgraded immediately?

[KWT]

Yeah clearly on the western side as Derek has also said. I think its probably the right idea the NHC waited till the Vis.imagery came in. It has taken a western jog though thats also true.

I wouldn't upgrade it either just yet, though Danny was upgraded with a similar presentation to be fair.

[otowntiger]

Well it all makes sense. In the 5 days or so that we've been watching this thing eagerly anticipating something, all the while virtually no convection, now that it finally seems to have a good burst, its encountering westerly shear and now the bouy readings are depicting a less than impressive system internally. Go figure.

[gatorcane]

seems that all models except CMC now bend it back to the west just north of the Leewards and Puerto Rico.....

[Derek Ortt]

if this deosn't develop today, it probably does not develop at all given the latest shear trends

I am curious, just how HORRIFIC does the upper shear forecasts have to be before changes are made? These shear forecasts are embarrassing. Last night, SHIPS was showing strong EASTERLY shear affecting this in 48 hours.