ATL : HARVEY - Tropical Depression - Discussion

[Vortex]

In 2-4 days, id be shocked if she didnt make a robust comeback...50w is her magic number IMO....

[Gustywind]

Here is this morning's discussion of 93L by Rob of Crown Weather.
http://www.crownweather.com/?page_id=4557

Invest 93L Located 700 Miles Southwest Of The Southern Cape Verde Islands:
Invest 93L, which is a broad area of low pressure, was located about 700 miles to the southwest of the southern Cape Verde Islands. Shower and thunderstorm activity has greatly diminished over the past 24 hours and is producing very little in the way of shower activity this morning. At this point, immediate development is highly unlikely. Given that this system is expected to stay weak for the next few days means it will take advantage of the low-level wind flow and remain on a westerly course towards the Caribbean.

Our friends in the Lesser Antilles should keep an eye on this system as it is expected to track across the Lesser Antilles on Tuesday. Both the latest GFS model forecast shows 93L tracking across Barbados and the Windward Islands on Tuesday as a weak system, perhaps a tropical depression.

Once Invest 93L enters the eastern Caribbean early Wednesday, the European model guidance forecasts that this system will track across the entire length of the Caribbean and into the Yucatan Peninsula 10 days from now. The GFS model forecasts that 93L will track west-northwestward across the northern Caribbean next week and then turn northward across central and western Cuba late next weekend before traveling north-northeastward right along the US Eastern Seaboard between August 23 and August 26.

The strong trough of low pressure that will be responsible for taking Invest 92L out into the open Atlantic will lift out by the middle part of next week. This will be replaced by a ridge of high pressure that will develop over Quebec province. A weakness in the ridge of high pressure may exist along the US Eastern Seaboard next week leading to the possibility of 93L curving northwestward out of the Caribbean and towards the US Southeast coast, much like what the GFS model is forecasting.

At this point, the Lesser Antilles are the ones that should watch 93L in case it develops late this weekend into early next week before it tracks across Barbados and the Windward Islands on Tuesday. Right now, I don’t think it will develop very much, if at all before it reaches the Caribbean. However, once it gets into the Caribbean during the middle and later parts of next week, I think it has a chance to develop and intensify, especially given that the upward motion pulse of the Madden Julian Oscillation will be kicking in during the second part of this month and also just because of climatology.

[Kory]

The Euro continues to show a weak system entering the southern Gulf of Mexico after crossing the Yucatan with a ridge building over the East Coast. Its going to be an interesting week ahead. Too bad school starts up next Wednesday...

[Kory]

What I'm looking for is consistancy and the Euro on the past few runs has been pointing at the Yucatan and southern Gulf. Unlike the GFS which has been all over, the Euro is somewhat consistant. We shall see if it continues come 12z model runs...

[Kennethb]

Yes, I concur with the looking for consistency in model runs and not the specifics and especially in the long range. I noted that both GFS and Euro were consistent with the feature near the Yucatan at 240 hours on the 0z run, including trough near the great lakes. Timing, strengths, locations of the troughs and ridges obviously in the long range will play a role in the specifics.

[GCANE]

In 2-4 days, id be shocked if she didnt make a robust comeback...50w is her magic number IMO....

Agreed Vortex. They just about always have a hard time before 50W.

After that another challenge would be east Carib.

Action typically gets going in the mid / west Carib.

[cycloneye]

No 12z run by the Bamms.

[cycloneye]

Invest 93L is still active at the atcf site,despite the no run made at 12z by the Tropical Models.

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

[underthwx]

https://my.sfwmd.gov/sfwmd/common/image ... orm_93.gif


morning all, not sure if these models have been as of yet, but, here we go.

[otowntiger]

While the models depict an interesting track with this system the bigger question seems to be what shape will it be in by the time it approaches any land masses if it even still exists by then.

[ROCK]

No 12z run by the Bamms.

nope...they will probably deactivate it once it starts looking better....never fails...

[ROCK]

In 2-4 days, id be shocked if she didnt make a robust comeback...50w is her magic number IMO....

Agreed Vortex. They just about always have a hard time before 50W.

After that another challenge would be east Carib.

Action typically gets going in the mid / west Carib.

good...I am can stop staying up for the EURO for a few days....

[Nimbus]

So 94L and 92L follow Franklin out to sea where they become extratropical. Bad news is 93L stays weak and misses the first trough. We don't know how 93L will track once it gets into the Caribbean but if it doesn't start to spin up near 50W it may go harmlessly west into Mexico as a weak TS.

[SoupBone]

000
AXNT20 KNHC 131153
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT AUG 13 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...TROPICAL WAVES...

A 1011 MB LOW IS OVER THE E ATLANTIC OVER THE E ATLANTIC ABOUT
650 MILES WEST-SOUTHWEST OF THE SOUTHERN CAPE VERDE ISLANDS AT
12N34W. A TROPICAL WAVE EXTENDS N FROM THE LOW TO 17N36W. ONLY
LIMITED SHOWER ACTIVITY IS NOTED. THE SYSTEM IS MOVING W AT
13-18 KT.


$$
FORMOSA

13-18 knots? That's pretty quick. Is it possible that this thing could keep moving West, slam into Central America and die?

[lonelymike]

So Rock how does treated sewerwater taste?

[Macrocane]

13-18 knots? That's pretty quick. Is it possible that this thing could keep moving West, slam into Central America and die?

It coud slam in Central America but before that it may develop but that would happen only if the ridge amplifies west, anyway it won't be moving that fast always, in the Caribbean it will surely slow down as the flow is slower in that region.

[Epsilon_Fan]

on the visible, it looks like 93L is on a leash attached to 92L

[cycloneye]

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

So far in 2011,the pattern has been for waves to look very good as they emerge Africa,but as soon they hit the zone of dry air,they go down. Will this be the rule for the rest of the CV season? I know the wet MJO is comming very soon,but is interesting to see this going on. We may have to wait for the waves to start to develop closer to the Antilles or Western Atlantic if this keeps up.

[Rgv20]

0zECMWF and 12zGFS forecast the 850mb vorticity of 93L almost to disappear today with a decent 850 vorticity coming back by tomorrow night early Monday morning around 50W. The new 12z run wants to develop 93l just before crossing the Lesser Antilles but looking at weak state it is now I would put more weight on the Euro which keeps it weak as it crosses the Lesser Antilles.

[Sanibel]

Plenty moist here if anything makes it across the mid-Atlantic dry air gaunlet.