Atlantic Invest Thread 2010

[The PIT]

Surprised really with la Nina getting going I would have expected more. Perhaps the fish spinners have made the SST's a little less favourable????

Strange year very quiet suddenly wham then quiet again.

[Somerset Squall]

Well, the Cape Verde season is coming to an end now, as the SST's in the Eastern Atlantic are falling which is normal. Activity in October generally therefore trends towards the Caribbean and GOM. There are two disturbances in the Caribbean at present but there is a rather large ULL (upper level low) parked nearby (much like the beginning of the season), so they are struggling to develop. I expect activity to pick up again, the waters are still really toasty in the Carribean and IMO, if it was not for the ULL in the Caribbean, we would have seen Otto by now, continuing the active period.

[Cookie]

We now have 98L

[Somerset Squall]

98L looking quite impressive now, looked very lopsided earlier but the circulation is now clear to see with convection beginning to wrap around from the western quadrant. If this continues, 98L could become a tropical depression from as early as tomorrow.

[Cookie]

98L

sitting at 60% this afternoon

[Cookie]

98L

up to 100%

TROPICAL WEATHER OUTLOOK

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL

200 PM EDT MON OCT 11 2010

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

SATELLITE IMAGES...SURFACE OBSERVATIONS...AND DATA FROM AN AIR FORCE

RESERVE HURRICANE HUNTER AIRCRAFT INDICATE THAT A TROPICAL STORM

MAY BE FORMING NEAR THE NORTHEASTERN COAST OF HONDURAS. ADVISORIES

WILL LIKELY BE INITIATED LATER THIS AFTERNOON...AND WATCHES AND/OR

WARNINGS WILL BE REQUIRED FOR PORTIONS OF THE COAST OF HONDURAS...

BELIZE...AND THE YUCATAN PENINSULA OF MEXICO. THERE IS A HIGH

CHANCE...NEAR 100 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL

CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES NORTHWESTWARD AT

AROUND 10 MPH. HEAVY RAINFALL IS POSSIBLE OVER PORTIONS OF

NICARAGUA...HONDURAS...BELIZE...THE YUCATAN PENINSULA...THE CAYMAN

ISLANDS...AND WESTERN CUBA DURING THE NEXT COUPLE OF DAYS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE

NEXT 48 HOURS.

$$

FORECASTER BERG/BRENNAN

[Somerset Squall]

98L became Hurricane Paula.

Invest 99L formed a few days ago in the southwestern Carribean. The system has tracked northwestwards with little organisation until now. A broad LLC with 30kt winds has formed in association with increasing convection. NHC give a 70% chance of a tropical depression forming from 99L in the next couple of days. All 99L needs is the LLC to be a little tighter and it could be upgraded tomorrow.

[Paranoid]

GDFL brings 99L up to a Category 4 south of Cuba, although the other models dont back this up. One of the other models, maybe CMC shows another system making its way into the Carribean from the open Atlantic, and could be worth watching if it materialises.

[Paranoid]

As an update to my previous post, the GFDL continues to forecast agressive strengthening of what could potentially become Richard. Last 2-3 model runs have brought it up to a Cat 5 just about the thread the needle between the Yucutan and Cuba. The GFDL is the only model that forecasts this though, all the others forecast a lanfall in Belize/Mexico.

[Iceberg]

Looking at the tracks attached, this could realistically go anywhere.

HWRF supports the GFDL in the cuban/yucatan bypass and also makes it a Major if this route is taken.

Globals still not keen at all with ECM showing no development of this system and GFS showing little until landfall in central america.

[Somerset Squall]

99L has become TS Richard.

Invest 90L has formed south of the Cape Verde Islands. The system looks well organised with fairly deep convection forming near a developing low pressure area. Tropical cyclone formation in this area at this time of year is VERY rare as sea temps are usually too cool and the upper level environment too hostile. Upper level winds are expected to increase over the coming days reducing the risk of development. However, conditions are unusually good in the short term, and NHC give 90L a medium chance, 30%, of becoming a tropical cyclone within the next 48hrs.

Edited October 21, 2010 by Somerset Squall

[Cookie]

their has never been anything to form in this area before at this time of year, very interesting system indeed!!

[Somerset Squall]

90L has travelled northwestwards over the last week and now lies at 27N, 41W. The disturbance has struggled to develop due to high shear and proximity to an upper level low (which now, oddly enough, is showing signs of tropical development itself). However, shear is expected to ease, and with a 30kt circulation in place, a subtropical or tropical depression could form in the next couple days. NHC give a 30% probability of this occuring.

Invest 91L has formed much further south, just 6 degrees north of the equator. Waters are plenty warm here, though 91L is suffering from a lack of spin at present. As the invest lifts out towards the warm waters of the Caribbean, some slow development is possible, and thus this disturbance bears watching. In the next 48hrs however, NHC gives a 10% chance of tropical depression formation.

The upper level low I described hindering 90L has become invest 92L, located to the west of the former. Convection is increasing over the circulation, and this could help bring it down towards the surface. Shear is easing which could also aid this development. NHC give a 20% chance of TD formation in the next 48hrs, though chances may rise after this as upper level lows can take their time extending to the surface.

[Cookie]

A view of the Atlantic

[Somerset Squall]

90L looked close to tropical storm status this morning, but convection has been sheared away from the LLC again. The well defined LLC has winds of 35kts though, so if convection became more organised, then a tropical storm would be declared.

91L has become much better organised over the last 24hrs, rotation is strong and convection is increasing. The system could become a tropical depression soon but land interaction may be a problem at first. Once the system moves into the Central Carribean, development chances are good.

92L looks close to tropical depression status. Winds are 30kts and convection is concentrated around the proposed centre. Quickscat shows that the LLC may not be fully closed yet, but NHC give a 60% chance of TD formation in the next 48hrs.

[londonsnow]

hello shary

[Jack Wales]

91L looking really good now with excellent outflow, strong bursting convection plus good circulation and symmetry. Could go straight to TS by tonight.

[Somerset Squall]

I agree Jack, banding is really impressive along with building central convection. 91L looks set to become a tropical cyclone later tonight.

92L became Tropical Storm Shary.

[Paranoid]

92L looks like it could easily be a TS already, so we may have Tomas on the 10pm advisory (only the 3rd "T" storm ever if it forms). Might make it up to minimal Hurricane strength in the Caribbean judging from the models (GFDL has a lot of problems picking it up and tracking it though), but i'll need to have a look at shear and SSTs.

[Somerset Squall]

TC formation chances have been upped to 90% in the latest TWO. Recon are flying in and as Parnoid says, they could well find a tropical storm. Has the structure of a biggie if the environment plays ball.

[Paranoid]

Probability has been upped to near 100% and NHC have pretty much acknowledged that 91L is now TS Tomas.

[Somerset Squall]

So yes, 91L has become TS Tomas.

Very interesting to note there are only two names left on the list before the greek alphabet starts to be used? Will this happen for the 2nd time in recorded history?

[Paranoid]

Depends whether activity gradually winds down or stops abruptly. We may still see a few storms in November/December if conditions are good, keep in mind we are still a full month away from the offical end of the season, although most systems tend to end in late October/early November.

[Somerset Squall]

I think there is a good chance, October has been more active than normal with 5 named storms (with the possibility of all of them being hurricanes- Shary looks very close this morning and Tomas should become a hurricaane), so unless there is an abrupt stop in activity we could well see the greek alphabet bing used again.

[Cookie]

we have invest 94L