ATL : TROPICAL DEPRESSION ERIKA (06L)

[Stormcenter]

It sure looks like it's moving more northward then westward. IMO

[Derek Ortt]

CMC is far too intense with this system. I don't look for conditions to improve until at least the week-end. Maybe no development until this is in the Bahamas now

[tolakram]

The shear just to the west of the blob is extreme. I really expect this to be stripped naked unless something changes quickly.

[Ivanhater]

CMC is far too intense with this system. I don't look for conditions to improve until at least the week-end. Maybe no development until this is in the Bahamas now

Great,where it will be under a building high

[expat2carib]

Observed Weather for past 24 hours
Reported by the Barbados Meterological Service
Grantley Adams International Airport

Time
EDT (UTC) Temperature
F (C) Dew Point
F (C) Pressure
Inches (hPa) Wind
MPH

1 PM (17) Aug 31 86 (30) 75 (24) 29.85 (1011) ENE 16
Noon (16) Aug 31 87 (31) 75 (24) 29.88 (1012) E 16
11 AM (15) Aug 31 86 (30) 75 (24) 29.91 (1013) ENE 15
10 AM (14) Aug 31 86 (30) 75 (24) 29.91 (1013) ENE 17
9 AM (13) Aug 31 86 (30) 75 (24) 29.91 (1013) E 17
8 AM (12) Aug 31 84 (29) 75 (24) 29.88 (1012) E 16
7 AM (11) Aug 31 82 (28) 73 (23) 29.88 (1012) ENE 13
6 AM (10) Aug 31 80 (27) 73 (23) 29.85 (1011) ENE 13
5 AM (9) Aug 31 80 (27) 73 (23) 29.85 (1011) ENE 14
4 AM (8) Aug 31 80 (27) 73 (23) 29.85 (1011) ENE 13
3 AM (7) Aug 31 80 (27) 73 (23) 29.85 (1011) ENE 15
2 AM (6) Aug 31 80 (27) 73 (23) 29.85 (1011) ENE 14
1 AM (5) Aug 31 82 (28) 73 (23) 29.88 (1012) ENE 18
11 PM (3) Aug 30 82 (28) 75 (24) 29.91 (1013) ENE 16
10 PM (2) Aug 30 82 (28) 75 (24) 29.91 (1013) ENE 17
9 PM (1) Aug 30 82 (28) 75 (24) 29.91 (1013) ENE 17
8 PM (0) Aug 30 82 (28) 77 (25) 29.88 (1012) ENE 16
7 PM (23) Aug 30 82 (28) 75 (24) 29.85 (1011) ENE 16
6 PM (22) Aug 30 82 (28) 75 (24) 29.85 (1011) ENE 15
5 PM (21) Aug 30 84 (29) 75 (24) 29.85 (1011) ENE 20
4 PM (20) Aug 30 84 (29) 75 (24) 29.83 (1010) ENE 21
3 PM (19) Aug 30 87 (31) 75 (24) 29.85 (1011) E 20

[tailgater]

I looking at some HI res visible loops and can't find a distinct center, so I can't see why folks are saying it's moving this way or that way. 57 maps don't actually prove there is a LLC to follow.

[Derek Ortt]

there are no guarantees of a building high in the Bahamas. Not if the UL to the west does not move. This could go from one UL to another

[Ivanhater]

there are no guarantees of a building high in the Bahamas. Not if the UL to the west does not move. This could go from one UL to another

From what I've seen from the models, they are stongley suggesting building heights along the east coast. But you are right, if there is an ULL present, it would change things.

[wxman57]

strong shear from the upper low and a low level easterly wind surge. 700mb winds at Barbados are close to 30KT

Here's the 00hr GFS 12Z analysis of 700mb wind isotachs. Crosshairs represent center of 94L - heading for the increasing 700mb winds. Now the GFS does forecast this high wind area to be gone in the next 24 hours.

[Derek Ortt]

not sure I trust anything SAL related from the GFS though

[wxman57]

I looking at some HI res visible loops and can't find a distinct center, so I can't see why folks are saying it's moving this way or that way. 57 maps don't actually prove there is a LLC to follow.

You have to "step back" away from your monitor and force your eyes to ignore all the bright white cirrus clouds and focus only on the dim, small lower clouds streaming toward the weak center. If you do that, you'll notice a NW movement.

[AtlanticWind]

Latest analyisis from Dr Jeff Masters

Invest 94L
The well-organized tropical wave (94L) near 14.5N, 52W, about 500 miles east of the central Lesser Antilles Islands, continues to be a threat to develop into a tropical depression. Visible satellite imagery and this morning's QuikSCAT pass do not show a surface circulation yet, though 94L does have a large envelope of moisture and some modest heavy thunderstorm activity. QuikSCAT noted winds up to 30 mph. Water vapor satellite loops show that 94L has moistened the region surrounding it considerably, and dry air from the Saharan Air Layer is not a major impediment to development. Wind shear is a low 5 - 10 knots, and the ocean temperature are a moderately warm 28°C. Visible satellite loops over the past two hours show low-level spiral bands developing on 94L's northeast side, and I give a 70% chance the Hurricane Hunters will find a tropical depression or tropical storm on Tuesday when they investigate 94L.

The center of 94L probably passed over Buoy 41040, located at 14.5N, 53W over the past hour. Winds blew northeasterly early this morning, then went calm, then shifted to southerly late this morning. The winds were less than 10 knots during the center passage, so the circulation of 94L is not yet well-defined. The pressure fell significantly as 94L moved over the buoy (seen only after one removes the wiggles due to daily atmospheric tide effect present in the tropics). 94L will appear on Martinique radar on Tuesday.

The forecast for 94L
Shear will remain low, 5 -10 knots, over the next 5 days, SSTs will be warm, in the 28 - 29°C range, and dry air should have only a minor inhibiting effect, so I can't see anything that will prevent 94L from developing into a tropical depression over the next 1 - 2 days. The HWRF model develops 94L into a hurricane 4 days from now, as does the SHIPS intensity model, but other models, such as the GFDL, ECMWF, and GFS, do not develop 94L at all.

Model solutions for the track of 94L are divergent. Water vapor satellite loops show two upper-level lows to the north and northwest of 94L that are pulling the storm to the west-northwest, and 94L's motion is expected to range between the west-northwest and northwest over the next three days. By Tuesday, 94L will slow down from its current 15 mph forward speed to about 10 mph. Most of the models predict that the steering influence of the upper-level lows will pull 94L far enough north that the storm will miss the Lesser Antilles, with a closest approach occurring Wednesday and Thursday. However, the ECMWF and HWRF models have 94L passing within 200 miles of the islands, and the northern Lesser Antilles may experience tropical storm conditions on Thursday.

At the longer ranges, the fate of 94L is highly uncertain. The Canadian model turns 94L to the north near Bermuda, then out to sea, while the NOGAPS model foresees a threat to the U.S. East Coast early next week. Both of these solutions are believable. The Hurricane Hunters are scheduled to make their first flight into 94L on Tuesday afternoon at 2pm EDT.

One thing I have noticed, Jeff Masters has a high bias with his predictions

Relly disagree on this point , I have read Jeff Masters for years , always has a reasoned approach does not hype storms like JB . His blogs give balanced info and possibilties,

[george_r_1961]

I think this system is going bye bye real soon.

[otowntiger]

there are no guarantees of a building high in the Bahamas. Not if the UL to the west does not move. This could go from one UL to another

Not to be argumentative but really there are no guarantees regarding this system. No one can guarantee that this system won't or will develop. No human nor computer alike seems to have a real grasp on intensity forecasts for any tropical system. It seems we are time and time again surprised by a system that either develops when it 'shouldn't' or does not develop when it 'should'.

[wxman57]

not sure I trust anything SAL related from the GFS though

You're not a very trusting person. OK, how about the text version of the TBPB sounding from 12Z today to demonstrate what you were saying about the 700mb winds? (below). This increasing low-level easterly flow across the Caribbean (and sometimes just east of the Caribbean) has created a "zone of death" in 2009.

[Aric Dunn]

I looking at some HI res visible loops and can't find a distinct center, so I can't see why folks are saying it's moving this way or that way. 57 maps don't actually prove there is a LLC to follow.

You have to "step back" away from your monitor and force your eyes to ignore all the bright white cirrus clouds and focus only on the dim, small lower clouds streaming toward the weak center. If you do that, you'll notice a NW movement.

the rgb is better way than looking at just regular visible as it highlights the different levels ... the low levels are yellow tint and the midlevel is a brighter white and the highest is blue-ish.

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

but there is a illusion of a NW motion. the elongated circulation that is tilted gives that appearance but tracking the overall center still leads to wnw as the nhc has said.

[Derek Ortt]

and I'm not sure that "zone of death" is going away as fast as GFS says

[Gustywind]

[Steve H.]

I disagree with Master's take on the shear. The shear has been relentless in the Tropical Atlantic and if it doesn't abate soon the GFS/EC solutions may be correct.....a very weak system at best.

[cycloneye]

ABNT20 KNHC 311755
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT MON AUG 31 2009

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

SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A BROAD AREA OF LOW
PRESSURE LOCATED ABOUT 500 MILES EAST OF THE LESSER ANTILLES
CONTINUE TO SHOW SIGNS OF ORGANIZATION...HOWEVER THERE IS NO
WELL-DEFINED SURFACE CIRCULATION CENTER. CONDITIONS ARE MARGINALLY
FAVORABLE FOR THIS SYSTEM TO BECOME A TROPICAL DEPRESSION DURING
THE NEXT DAY OR SO AS IT MOVES WEST-NORTHWESTWARD AT AROUND 15 MPH.
THERE IS A HIGH CHANCE...GREATER THAN 50 PERCENT...OF TROPICAL
CYCLONE FORMATION IN THIS AREA DURING THE NEXT 48 HOURS. INTERESTS
IN THE LESSER ANTILLES SHOULD MONITOR THE PROGRESS OF THIS SYSTEM.

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

$$
FORECASTER PASCH