TS Emily: 215 Miles SSE Of San Juan, PR

[Typhoon Tip]

TROPICAL WEATHER OUTLOOK

NWS NATIONAL HURRICANE CENTER MIAMI FL

800 PM EDT SUN JUL 31 2011

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

AN ELONGATED AREA OF LOW PRESSURE EXTENDING FROM THE LESSER ANTILLES

EASTWARD SEVERAL HUNDRED MILES INTO THE TROPICAL ATLANTIC OCEAN IS

PRODUCING A LARGE BUT DISORGANIZED AREA OF SHOWERS AND

THUNDERSTORMS. CONDITIONS ARE EXPECTED TO REMAIN FAVORABLE FOR A

TROPICAL DEPRESSION OR TROPICAL STORM TO FORM...AND THIS SYSTEM HAS

A HIGH CHANCE...90 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING

THE NEXT 48 HOURS AS IT MOVES WEST-NORTHWESTWARD AT AROUND 15 MPH.

IF THE SYSTEM BECOMES A TROPICAL CYCLONE TONIGHT OR MONDAY...

TROPICAL STORM WATCHES OR WARNINGS WOULD BE ISSUED FOR PORTIONS OF

THE NORTHERN WINDWARD ISLANDS AND THE LEEWARD ISLANDS ON VERY SHORT

NOTICE...AND INTERESTS IN THESE AREAS SHOULD CLOSELY MONITOR THE

PROGRESS OF THIS SYSTEM. A HURRICANE HUNTER AIRCRAFT IS SCHEDULED

TO INVESTIGATE THIS SYSTEM MONDAY MORNING. REGARDLESS OF TROPICAL

CYCLONE FORMATION...THIS SYSTEM WILL BRING LOCALLY HEAVY RAINFALL

AND GUSTY WINDS TO PORTIONS OF THE LESSER ANTILLES TONIGHT AND

MONDAY.

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

NEXT 48 HOURS.

$

FORECASTER BRENNAN

Folks may want to watch that Wave that has just emerged from off the African continent in the far eastern Atlantic over the coming days. Typical convective recession has occurred post departing land but it is deeply embedded in the ITCZ trough with unabated anticyclonic flow aloft, with off course SSTs nearing seasonal max.

I bring it up because it has a massive cyclonic circumvallate and unlike predecessors, SAL appears to be displaced farther N of it axis.

Also, for those who know of ... The Roundy Probabilities are firing up the CV district by mid August, and showing even modest anomalies - more importantly - in that vicinity, eventually showing up along the EC. The product has shows some skill in the past.

[HurricaneJosh]

Right now it is an impressive but elongated mess. For much of today, there have been two distinct complexes, one which was along the wave axis and appears to have included a low level circulation (which is now lagging behind this front complex, falling back just a bit and is moving relatively slowly compared to the wave axis), and a region to the East which has contained the mid/upper level vort maxes and has been the main region of the disturbance. Recon was going in to see what was up, but little data from the storm made it out because of large communication problems (the most recent data is from before 2pm), making it even harder to tell what has been going on. As to the future track, a Northward track from a strong system in the short term seems more unlikely because it is likely going to take some time to consolidate, keeping the system weaker for the short term.

Awesome summary-- thanks, dude!

All can say is: I'm glad I haven't been following tue blow-by-blow with this. It sounds like it's been a tedious day for tropical dudes.

[Uncle Bobby]

Yo-- I've been roadtripping around Matagorda Bay the last 24 hr and I've essentially been offline. I see it's been a 100% cherry forever. lolz

Is this a fish? A shredded island-hopper? Summary, plz.

Josh, to summarize even shorter than Dan: Start getting tingles. Emily will be a threat to make a USA landfall, but where exactly is not yet known. Could be EC, could be GoM.

[HurricaneJosh]

Ha-- it's been demoted. I've never seen that happen to a 100% cherry before. They should have said 99%.

[dan88]

Recon data for the flight has finally come in over the past 20 minutes. It looks like the mission focus has been on the Eastern complex, reaching the low levels at 05530W

(all times UTC)

Looking through the data, the mission was done at 975mb or lower, so only has an idea of near surface conditions. There were at times some west winds, but rarely higher in degree then 210 degrees (so SW-SSW). Extrap pressures were mainly above 1010mb. The closest thing to a center they found was 1925 onward, where you had 25kt winds at ~150 degrees at 1444N 05246W (worth noting, 26kts was the peak for the mission) and 1011.9 pressure, become ~210 degrees at 3kts and a local minimum of 1010.8mb at 1450N 05314W.

Below is a link containing line by line from 1700-2045, which includes the entirety of the recon mission while at mission altitude in High-Density Observations format. The simple summary though, it is a very messy disturbance.

http://privatepaste.com/a65c9b84c2

[HurricaneJosh]

Josh, to summarize even shorter than Dan: Start getting tingles. Emily will be a threat to make a USA landfall, but where exactly is not yet known. Could be EC, could be GoM.

You think?? Interestin'. I've been hearing all this fish talk, and the models do show it gaining lots of 'tude (latitude, that is) later on.

[Typhoon Tip]

Diurnal flux looks like it's beginning ...

[EasternUSWX]

Diurnal flux looks like it's beginning ...

Wonder if this one can get it over the hump.

[phil882]

Josh, to summarize even shorter than Dan: Start getting tingles. Emily will be a threat to make a USA landfall, but where exactly is not yet known. Could be EC, could be GoM.

I'll say right now that there is a near 0% chance that this is going into the GOM... it would require a major shift in the modeling that is likely not in the cards.

The main thing to watch at this point is the subtropical high centered over the central United States. This feature has had a very difficult time moving westward throughout the summer, only making it across in a few instances. The GFS shows the subtropical high remaining anchored over the Central US, but pieces of ridging do manage to shift into the Eastern United States. However, There is also a subtropical ridge located to the east of our feature that will try to steer it more northward. As the first trough (the red dotted line) passes by, it will slow down the progress of our system, but likely not be able to recurve it as the trough will amplify too early (in the 72-96 hour period). There might be a brief period where ridging tries to rebuild, but it will likely be transient like the GFS suggests unless we get the entire subtropical ridge over the Central United States to move eastward. How long that brief period of ridging lasts will likely determine if we get a mainland US landfall or not. At this point though, the most likely solution is that the slight ridging will quickly shift over and merge with the building subtropical high to the east, which will eventually kick the storm northward and then northeastward late in the forecast period. I'm still thinking a turn northeast before the system reaches the east coast is more likely than not at this point.

[Uncle Bobby]

You think?? Interestin'. I've been hearing all this fish talk, and the models do show it gaining lots of 'tude (latitude, that is) later on.

Yes, based on what others have been saying, i.e.:

1) It's looking less likely that there will be quick organization due to it being a big blobby oval mess right now, and therefore

2) It will stay at a lower lat (than the early spaghetti) for enough time to pose that threat.

[hurricaneman]

The things that we have to look for is when is this going to develop and what will be the track, if this develops later, it probably will be farther west, but if it gets its act together sooner, this will probably head towards the Bahamas via unfortunately Puerto Rico and out, so this really need to be watched just in case

[28storms]

[Typhoon Tip]

I'll say right now that there is a near 0% chance that this is going into the GOM... it would require a major shift in the modeling that is likely not in the cards.

The main thing to watch at this point is the subtropical high centered over the central United States. This feature has had a very difficult time moving westward throughout the summer, only making it across in a few instances. The GFS shows the subtropical high remaining anchored over the Central US, but pieces of ridging do manage to shift into the Eastern United States. However, There is also a subtropical ridge located to the east of our feature that will try to steer it more northward. As the first trough (the red dotted line) passes by, it will slow down the progress of our system, but likely not be able to recurve it as the trough will amplify too early (in the 72-96 hour period). There might be a brief period where ridging tries to rebuild, but it will likely be transient like the GFS suggests unless we get the entire subtropical ridge over the Central United States to move eastward. How long that brief period of ridging lasts will likely determine if we get a mainland US landfall or not. At this point though, the most likely solution is that the slight ridging will quickly shift over and merge with the building subtropical high to the east, which will eventually kick the storm northward and then northeastward late in the forecast period. I'm still thinking a turn northeast before the system reaches the east coast is more likely than not at this point.

Eh, well you are probably right, I wouldn't set that at 0% - unless of course you are just being expressive

Anyway, there has been some flux in the SOI index lately and believe it or not there is a weak teleconnector out there for positive geopotential anomalies over the SE U.S. and adjacent SW Atlantic Basin with easterly waves passing through the SOI. Just fwiw, but if this remains weak and gets into the Caribbean as a "cruiser", ...just look at the UKMET at D6. It could be trapped on a WNW trajectory from a position in the Caribbean beneath blocking ridge with west -east axis N.

Perhaps remote as a possibility but certainly not 0.

[Ed Lizard]

Outer grid 500 mb heights on 18Z GFDL, is moving NW near the Bahamas, through a weakness in the subtropical ridge position, but it appears steering is light, and the ridge at 120 hours appears to be trying to rebuild in ahead of this. If the GFDL is generally correct, I could see extrapolating a threat (hit or near miss) to the SE US.

[Jaguars]

Wow, might have to keep my eye on this one. Looks like SE Fla too far south but the steering currents could be quirky enough for a rare NE Fla threat.

[phil882]

Eh, well you are probably right, I wouldn't set that at 0% - unless of course you are just being expressive

Anyway, there has been some flux in the SOI index lately and believe it or not there is a weak teleconnector out there for positive geopotential anomalies over the SE U.S. and adjacent SW Atlantic Basin with easterly waves passing through the SOI. Just fwiw, but if this remains weak and gets into the Caribbean as a "cruiser", ...just look at the UKMET at D6. It could be trapped on a WNW trajectory from a position in the Caribbean beneath blocking ridge with west -east axis N.

Perhaps remote as a possibility but certainly not 0.

Almost every model has a pretty expansive and deep upper level trough that will lift it out of the Caribbean in the day 3-4 period. This is already well established in the modeling and I see no reason to not believe it.

I don't have access to the UKMET at day 6, but at Day 5 I see it in the Bahamas.

[OSUmetstud]

Looks like we could see a track just east of that one. Looks like most models are hinting that this won't be a FL hit.

it won't hit NE, either

[#NoPoles]

i probably won't be up long enough to see how this next round of convective flare-up pans out...but in the beginning stages, it seems to be occurring around the center (i know it is broad and open, atm)

it has been struggling with the dry air...

[gkrangers]

it won't hit NE, either

I'm calling NJ.

[Doorman]

http://youtu.be/Oy1cDc4Pfdw

[#NoPoles]

this look familiar?

http://www4.ncsu.edu...floyd.track.jpg

that's all good and well, but how bout you try comparing the steering currents...just because a storm forms in the same area doesn't mean they will have the same track...that's so easy, a weenie should understand...

[Kmlwx]

this look familiar?

http://www4.ncsu.edu/~nwsfo/storage/cases/19990915/floyd.track.jpg

Try again...you need to look at the whole track as well as steering currents like thebigrombalski said. Come on. At least back up your posts with scientific evidence.

[Jaguars]

that's all good and well, but how bout you try comparing the steering currents...just because a storm forms in the same area doesn't mean they will have the same track...that's so easy, a weenie should understand...

calm down guy, i'm just throwing it out there

[Kmlwx]

calm down guy, i'm just throwing it out there

"he's" a she lol and you need to at least have something to back up your post. It is useless clutter without some kind of defense. At least give some analysis.

Example: I think this is a possibility given that ____ factors are in place and ____ so and so. Even if you are blatantly wrong just try.

[Sickman]

calm down guy, i'm just throwing it out there

Reel it back in. It has nothing to do with 91L, and it just clutters this thread up.

[winter_warlock]

i did also post a couple of tracks to compare too, but... i was just pointing out the similaritys, but i also understand there is so many variables with each system, that you have to account for, such as... steering currents, wind shere water temps, and so on. and the storm is more than a week away. still too far away to make any guesses.

[OSUmetstud]

[snowNH]

It's fairly easy to understand what it's showing if you read the heading.

So the model recognizes where the existing tropical system is, and then chooses the best analogous track and then comes up with a probability of landfall based on that BEST analogous track?

[David Reimer]

Explain? lol

I understand these instructions are based on common sense, so try to stick with me here for a moment. First, you read the title at the top of the image. After you read the title of the image, you look at the bottom of the image at the scale, which then gives you all the information you need in order to make an accurate judgement call on what the graphic is showing. Did you keep up or did common sense lose you? The image is based on past storms in the past that have been in the same position and conditions.

You and every other idiot noob that have contaminated this thread in the past two hours need to read more and post less, unless you enjoy the lack of any intelligent posts. If you do, go back to your snow threads.

[OSUmetstud]

So the model recognizes where the existing tropical system is, and then chooses the best analogous track and then comes up with a probability of landfall based on that BEST analogous track?

91L is an area where, climatologically, 15-20% of storms in that area have later hit the US East Coast. I would put the chances of an east coast impact at less than 10% since the pattern appears quite unfavorable for landfall.

Method:

The 6-hourly historical best-track dataset for the Atlantic, Eastern Pacific, and Western North Pacific were linearly interpolated to 10-minute increments. A 0.0833 degree (~6-10km) land-sea mask for the world (from http://polar.ncep.noaa.gov/sst/ophi/Welcome.html) was used to determine when each 10-minute interpolated position was over water or land. Tracking continued over land, such that the probability shown is for crossing an area, not only landfalling. For example, a tropical storm crossing New England after making landfall on the Gulf Coast still counts as "crossing" New England for these probabilities.In the near future, the track database will be extended in space and time using gridded reanalysis datasets. When this is done, similar risk maps for landfall in Europe and other locations will be produced.

Additional notes:

• Over-land tropical cyclone probabilities listed in the tables are Any Intensity / 64kt (hurricane/typhoon) / 96kt (major hurricane/super typhoon)
• A blank in the table means that all three probabilities are less than 1%.
• Shading in the table cells indicates "Any Intensity" threat at 10% (yellow), 25% (orange), 50% (red), and 75% (pink) thresholds.
• If a 1°x1° cell had less than 3 independent tropical cyclone occurrences, that cell was not used in the calculation shown here.
• A 9-pt smoother was applied twice to the 1°x1° grid, which leads to an underestimate of the risk close to the verification region. In other words, regions immediately near the coastline of verification regions should be much closer to 100%.
• No account is made for the evolution of observing or tracking technology over the period of record. This means that probabilities over the ocean distant from land masses likely have considerable biases -- perhaps including an overestimate of risk given storms far out to sea prior to satellites were less likely to reach land if undetected.
• Please remember that a TC doesn't have to make landfall to greatly impact a region. As a result, the probabilities here do not account for historical situations where a TC brushed land, but the TC never actually made landfall.
• Although Atlantic and East Pacific INVEST regions are plotted on the maps and probabilities displayed, the probabilties for INVESTs are obvious overestimates since a greater percentage of INVESTs do not develop than TDs and, further, no archive of INVESTs was included in the historical tracks from which the probabilities are calculated here. In other words, the probabilities for INVESTs should only be considered valid if they become TDs or stronger.
• We greatly appreciate the funding support of the Risk Prediction Initiative (RPI) of the Bermuda Institute of Oceanic Sciences (BIOS).
• This web page and its method are unrelated to the work of Brettsneider (2008; JAMC) [which was published while this work was underway unbeknowst to this author]. The method published in that 2008 paper is more robust than that used here and web users of this page are encouraged to read it.

http://moe.met.fsu.edu/tcprob/help.php