ATL: EMILY - Remnants

[AHS2011]

I live on Cape Cod, so should I be monitoring this system?

[weatherwindow]

as i mentioned earlier..luis or gusty have mentioned the 15/50 "rule" in the past ...for those unfamiliar with that rule of thumb ....i am paraphasing here...if a TC reaches 50deg W longitude prior to passing 15deg N latitude it tends to be a serious threat to the leewards and puerto rico..obviously this is not sufficient to "guarantee" a leeward/pr landfall, just a rule of thumb and i am sure many exceptions can be quoted....anyway extrapolating the ATCF TC alert box, it does appear that 91L/emily will meet that criteria.....rich

[chrisjslucia]

This is the extract from the NHC Tropical Discussion of 8am today. The text differs slightly from the Tropical Forecast, in that it makes specific mention forecasts of possible impact on Lesser Antilles:

A TROPICAL WAVE IS MOVING ACROSS THE EASTERN TROPICAL ATLC
ANALYZED FROM 19N49W TO A 1008 MB LOW CENTERED NEAR THE SOUTHERN
EXTENT OF THE WAVE NEAR 11N45W. THIS WAVE IS EMBEDDED WITHIN A
BROAD AREA OF DEEP MOISTURE ON TPW PRODUCT. BROAD CYCLONIC FLOW
IS WELL OBSERVED IN THE LOW LEVEL CLOUD PATTERN ON SATELLITE
IMAGERY. THIS WAVE WARRANTS WATCHING AS SOME MODELS FORECAST
DEVELOPMENT WITH A THREAT TO THE LESSER ANTILLES AND PUERTO
RICO. ENVIRONMENTAL CONDITIONS APPEAR FAVORABLE FOR A TROPICAL
DEPRESSION TO FORM OVER THE NEXT COUPLE OF DAYS. THIS SYSTEM HAS
A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48
HOURS AS IT MOVES WEST-NORTHWESTWARD AT 15 TO 20 KT. SCATTERED
MODERATE TO STRONG CONVECTION IS FROM 8N-14N BETWEEN 37W-50W.
THIS AREA OF CONVECTION IS ALSO RELATED TO THE ITCZ.

Given the potential to reach TS status or more by the time it reaches the Leewards and the track similarities to Tomas, I wonder how the NHC is going to advise on this over the next 48 hours. Many were critical last year at the delayed naming of Tomas. It is helpful they are including here specific points from the models, "..a threat to the Lesser Antilles and Puerto Rico" but as we know here, local reaction is often only triggered after NHC confirms a named system.

Always a difficult balancing act for the forecasters and one we all hope they get right!

[cycloneye]

Here is this morning's discussion of 91L by Rob of Crown Weather:

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For Official Information please refer to the NHC and NWS products.

http://www.crownweather.com/?page_id=4557

Invest 91-L Over The Central Atlantic Likely To Develop Into Tropical Depression #5/Tropical Storm Emily By Late Today Or Early Sunday & Is A Threat To The Islands Of The Northeastern Caribbean
Rob Lightbown on July 30, 2011, 7:57 am

Tropical Storm Don:
Don is essentially dead over southern Texas this morning. The storm evaporated over southern Texas due to the very dry air across the area due to the extreme drought conditions. I could find little, if any convection on satellite or radar imagery and it is expected that what is left of Don will open up into a trough of low pressure sometime today and unfortunately little additional significant rainfall is expected from Don. This will be the last discussion regarding Don.

Invest 91-L Located 900 Miles East Of The Lesser Antilles:
I think we have our first potential significant tropical cyclone threat of the 20111 Hurricane Season. Invest 91-L, located about 900 miles or so east of the Lesser Antilles, continues to become better organized as shower and thunderstorm activity has become more concentrated during the overnight hours. It does appear looking at data this morning that a fairly well organized surface circulation exists with Invest 91-L and I fully expect this system to be upgraded to Tropical Depression #5 either later today or at the latest during Sunday morning.

My thinking this morning is that this system will track in a general west-northwestward direction and track across the Lesser Antilles somewhere between the islands of Martinique and Guadeloupe on Monday night or early Tuesday morning.

As for strengthening over the next 48 to 72 hours, the circulation, while well established is elongated and satellite imagery indicates dry air both to the north and west of Invest 91-L. The HWRF and GFDL models do very little with this system while the SHIPS and LGEM intensity guidance forecasts strengthening to a hurricane by Monday. My opinion is that the HWRF/GFDL models may be too weak and the SHIPS/LGEM models may be too strong with intensity. So, I would say tropical depression by tonight or Sunday morning, then intensification into a tropical storm by Monday morning and a forecast of this to cross the Lesser Antilles as a 65 mph tropical storm Monday night or early Tuesday morning.

After crossing the Lesser Antilles, the global and track model guidance have some differing opinions on where they track future Emily.

The GFS model, which is the most aggressive of the global models, forecasts a landfall in Puerto Rico on Wednesday night and then tracks across the Turks and Caicos islands Thursday afternoon and Thursday night missing the Bahamas just to the east and missing the US Southeast coast due to a large trough of low pressure tracking off of the East coast at that time.

The Canadian model is also pretty aggressive and forecasts a track after the Lesser Antilles that takes it across the Virgin Islands and eastern Puerto Rico late Tuesday night and Wednesday morning and then forecasts this storm to miss the Bahamas and the US East coast well to the east due to a large trough of low pressure.

The European model forecasts a track that takes it across the eastern and northern Caribbean and onshore into Hispaniola on Wednesday where it dissipates.

The consensus track guidance like the TVCN and TVCC models forecasts a track that takes this storm across the island of Dominica on Monday night and then west-northwest from there that would take it very close to the coast of southwestern Puerto Rico on Wednesday morning and then inland into the Dominican Republic on Thursday morning.

So, here are my thoughts: The big question after future Emily tracks across the Lesser Antilles will be where will it track. A large trough of low pressure is forecast to track off of the US East Coast by the middle part of next week and will try to pull this system northward and out into the open Atlantic. My problem with this is that models like the GFS model tend to curve storms too quickly out into the open Atlantic. Remember, initially many of the model guidance members forecasted that Don will pull northward and near the Bahamas several days ago and well that didn’t happen. The global models forecast this trough of low pressure to track off of the US East Coast and then lift out by later next week with a ridge of high pressure building back in. This type of synoptic setup may be one where the trough does not pick up future Emily fully and causes the storm to turn back to the west. The forecast for later next week is obviously a long ways off and a lot can happen between now and then.

My main concern right now are the northeastern Caribbean Islands, including the Leeward Islands from Martinique northward to Anguilla, the US and British Virgin Islands, Puerto Rico and Hispaniola. Everyone across the islands of the northeastern Caribbean should prepare for this potential storm this weekend. Do not wait until watches and warnings are posted and become entangled in the last minute rush to buy supplies. This system is forecast to start affecting the islands of the northeastern Caribbean as early as Monday afternoon and potentially could be a moderate to strong tropical storm or even a hurricane.

Finally, the Bahamas, as well as the Turks and Caicos islands are my other concern as this storm may affect you by later next week. Everyone across the Bahamas and the Turks and Caicos Islands should closely monitor this system and go over your hurricane disaster supply kits this weekend.

Needless to say, I will be monitoring this system very closely and will keep you all updated.

[SouthFLTropics]

Very good write up by Crown Weather...Very in depth!

SFT

[crownweather]

Thank you SFT!! Appreciate your nice comments.

[RL3AO]

Someone mentioned it yesterday that troughs don't dig deep in early August combined with the point that Crown made with the models liking to curve early on means everyone from the East Coast to the Gulf Coast to Mexico to the entire Caribbean needs to keep their eyes on this.

[Aric Dunn]

ITs not looking to good this morning.. the vorticity seems to have weakened and it has become even more linear. likely due to its forward motion. will see what happens today..

[cycloneye]

ITs not looking to good this morning.. the vorticity seems to have weakened and it has become even more linear. likely due to its forward motion. will see what happens today..

In your view, no TD today?

[cycloneye]

12z Best Track

Reaches 12.0N.

AL, 91, 2011073012, , BEST, 0, 120N, 489W, 30, 1007, LO

ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/ ... 011.invest

[Aric Dunn]

ITs not looking to good this morning.. the vorticity seems to have weakened and it has become even more linear. likely due to its forward motion. will see what happens today..

In your view, no TD today?

Well for Now I will stick to my forecast from 3 days ago of a TC today. But after looking at everything this morning the chances have gone down quite a bit. I know there is still a LLC in there but its weak and only thing that is going to save it will be some deep convection.

[cycloneye]

12z Tropical Models

Code: Select all

WHXX01 KWBC 301302
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS NATIONAL HURRICANE CENTER MIAMI FL
1302 UTC SAT JUL 30 2011
 
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 (AL912011) 20110730 1200 UTC
 
        ...00 HRS...   ...12 HRS...   ...24 HRS. ..   ...36 HRS...
        110730  1200   110731  0000   110731  1200   110801  0000
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS    12.0N  48.9W   13.1N  51.7W   13.9N  54.5W   14.7N  57.1W
BAMD    12.0N  48.9W   13.0N  51.6W   13.9N  54.4W   14.4N  56.9W
BAMM    12.0N  48.9W   12.8N  51.5W   13.5N  54.2W   14.1N  56.6W
LBAR    12.0N  48.9W   13.5N  52.0W   14.8N  55.2W   15.9N  58.0W
SHIP        30KTS          34KTS          43KTS          50KTS
DSHP        30KTS          34KTS          43KTS          50KTS
 
        ...48 HRS...   ...72 HRS...   ...96 HRS. ..   ..120 HRS...
        110801  1200   110802  1200   110803  1200   110804  1200
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS    15.3N  59.6W   15.9N  64.0W   16.7N  67.4W   18.5N  70.1W
BAMD    14.7N  59.1W   14.8N  62.8W   15.7N  65.5W   18.5N  68.1W
BAMM    14.3N  58.8W   14.4N  62.3W   15.7N  65.0W   18.8N  67.6W
LBAR    16.7N  60.6W   17.6N  64.0W   18.9N  66.1W   21.4N  68.1W
SHIP        59KTS          72KTS          83KTS          82KTS
DSHP        59KTS          72KTS          83KTS          57KTS
 
         ...INITIAL CONDITIONS...
LATCUR =  12.0N LONCUR =  48.9W DIRCUR = 295DEG SPDCUR =  19KT
LATM12 =  10.3N LONM12 =  45.2W DIRM12 = 297DEG SPDM12 =  19KT
LATM24 =   9.0N LONM24 =  42.0W
WNDCUR =   30KT RMAXWD =   90NM WNDM12 =   30KT
CENPRS = 1007MB OUTPRS = 1010MB OUTRAD =  200NM SDEPTH =   M
RD34NE =    0NM RD34SE =    0NM RD34SW =    0NM RD34NW =   0NM


[cycloneye]

Is important to follow the movement because the islands are ahead and every bit it goes up,less threat will be for the islands from south to north.Right now Trinidad and Tobago is a place that it looks like is safe.Now lets see upstream as it continues moving WNW.

LATCUR = 12.0N LONCUR = 48.9W DIRCUR = 295DEG SPDCUR = 19KT

[Aric Dunn]

Is important to follow the movement because the islands are ahead and every bit it goes up,less threat will be for the islands from south to north.Right now Trinidad and Tobago is a place that it looks like is safe.Now lets see upstream as it continues moving WNW.

LATCUR = 12.0N LONCUR = 48.9W DIRCUR = 295DEG SPDCUR = 19KT

yeah 19kts... moving way to fast. if it were moving slower we would likely be looking at a TC already.

[x-y-no]

That Best Track position is on the very leading edge of the convection. Seems the low is outrunning it for now.

[RL3AO]

I live on Cape Cod, so should I be monitoring this system?

Its worth monitoring it.

[cycloneye]

12z Tracks.

[Ivanhater]

Yep, still too linear for my taste. Significant development still looks a few days away. The weaker it stays in the short term is good news for the Islands, but not so much for the mainland U.S.

[cycloneye]

Yep, still too linear for my taste. Significant development still looks a few days away. The weaker it stays in the short term is good news for the Islands, but not so much for the mainland U.S.

When you say significant development is a few days away, you mean it wont develop after it pass the Lesser Antilles?

[BobHarlem]

My guess is that it keeps moving west and stays generally in the Caribbean, Jamaica more than Hispaniola, maybe. Too many people want to jump on the models too soon and not look at the satellites, it happens over and over again here. Especially if it stays weaker and does this quick run to the west like it has now.