ATL: CHANTAL - Post-Tropical

[SFLcane]

12z GFS ensembles westward shift

[chaser1]

that ull is sure huge and it doesn't seem to be in hurry to get out of the way. I think shear and land interaction as it shows most spaghetti models having chantel cross western DR and Haiti and eastern cuba. so if this can hang on after all the crazy obstacles, what will the rest of the season bode? she got gusto that's for sure. dry air not as much of a factor eventhough north and south of chantel still has dry air but chantal continues to moisten environment around her. sheer and mountains going be her formidable enemies.

If Chantal somehow maintains tropical storm strength when in the Florida Straits or N.W. Bahamas, then "God Help Us All" if upper level conditions improve when "the big boys" start to roll around during August & Sept.!

[ScottNAtlanta]

Look familiar



Emily of 2011

[jhpigott]

Tropical storm conditions being mentioned by the national weather service in Miami.

http://forecast.weather.gov/MapClick.php?site=mfl&zmx=1.0416666666666667&zmy=1.0416666666666667&map.x=280&map.y=44#.Udxkk__D9es

Looks like Miami NWS has "Tropical Storm Conditions Possible" from about West Palm Beach north to the Martin County/Palm Beach County line.

[artist]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
225 PM EDT TUE JUL 9 2013

.AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
216 PM EDT TUE JUL 9 2013

...WET WEATHER WILL CONTINUE OVER SOUTH FLORIDA THROUGH THE WEEK...
...ALL EYES ON TROPICAL STORM CHANTAL FOR THE WEEKEND.TROPICAL SYSTEMS...
.....
TROPICAL STORM CHANTAL IS CURRENTLY FORECAST BY THE NATIONAL
HURRICANE CENTER TO MOVE TO THE BAHAMAS THIS WEEKEND. AT THIS
TIME...TROPICAL STORM FORCE WINDS CANT BE RULED OUT FOR SOUTH
FLORIDA...PARTICULARLY OVER THE COASTAL AND METRO AREAS OF PALM BEACH COUNTY
ALONG WITH THE ATLANTIC WATERS OF SOUTH FLORIDA FOR SATURDAY.
RESIDENTS AND VISITORS SHOULD CONTINUE TO MONITOR THE LATEST
FORECAST FROM THE NATIONAL HURRICANE CENTER THROUGHOUT THE WEEK AND
INTO THE WEEKEND...AS THE WEATHER OVER SOUTH FLORIDA WILL DEPEND ON
THE LOCATION AND STRENGTH OF CHANTAL.

http://www.nws.noaa.gov/view/prodsBySta ... ion#AFDMFL

[floridasun78]

Look familiar

http://img833.imageshack.us/img833/4171/zb1.gif

Emily of 2011

did she become hurr south haiti for shot life?

[ROCK]

Look familiar


Emily of 2011

Chantal not even close to Emily at the moment. She does not look all that great. Maybe after a 6 pack of shiner!!!

[adam0983]

Yes and stalled and got ripped to shreds by the mountains

[wxman57]

those outflow boundaries are usually a sign of weakening but this is not the case....this is an abnormal storm!

I think it IS the case. Clearly Chantal is struggling. So many outflow boundaries moving out away from the storm are not a sign of it becoming better organized. I'm not so sure it'll survive another 24 hours if the current forward speed doesn't decrease. And running into the DR won't help...

[robbielyn]

what are the current coordinates for the center?

[floridasun78]

let it die so we get rest see what else i n tropical

[Bocadude85]

those outflow boundaries are usually a sign of weakening but this is not the case....this is an abnormal storm!

I think it IS the case. Clearly Chantal is struggling. So many outflow boundaries moving out away from the storm are not a sign of it becoming better organized. I'm not so sure it'll survive another 24 hours if the current forward speed doesn't decrease. And running into the DR won't help...

Assuming she does survive her encounter with the DR what are you thoughts about the track?

[SapphireSea]

those outflow boundaries are usually a sign of weakening but this is not the case....this is an abnormal storm!

I think it IS the case. Clearly Chantal is struggling. So many outflow boundaries moving out away from the storm are not a sign of it becoming better organized. I'm not so sure it'll survive another 24 hours if the current forward speed doesn't decrease. And running into the DR won't help...

Seems like your also on the train with alot of mets being confused on how it can be closed while moving so fast. Seems like it's expanding as well, definitely not a sign of organization. **

[MortisFL]

Remember Debby from 2000.


Uploaded with ImageShack.us

[adam0983]

The cloud tops are cooling right now with Tropical Storm Chantal I think the rapid forward speed of this storm is finally taking its toll. Looks like Chantal could go poof and Dr McCoy is on standby. Just an opinion not a forecast.

[ROCK]

those outflow boundaries are usually a sign of weakening but this is not the case....this is an abnormal storm!

I think it IS the case. Clearly Chantal is struggling. So many outflow boundaries moving out away from the storm are not a sign of it becoming better organized. I'm not so sure it'll survive another 24 hours if the current forward speed doesn't decrease. And running into the DR won't help...

so I am not losing it! I was just going off the last RECON reports of falling pressures and higher winds...maybe the EURO was seeing something that the others were not..

[gatorcane]

those outflow boundaries are usually a sign of weakening but this is not the case....this is an abnormal storm!

I think it IS the case. Clearly Chantal is struggling. So many outflow boundaries moving out away from the storm are not a sign of it becoming better organized. I'm not so sure it'll survive another 24 hours if the current forward speed doesn't decrease. And running into the DR won't help...

Agreed she is struggling. It might be true the the NHC found her to be strengthening at 2pmEST but the SAT images coming in throughout the afternoon continue to show a more disorganized system with those outflow boundaries also showing she is struggling.

It also looks like some light to moderate WSW shear is starting to infringe upon her.

[Aric Dunn]

those outflow boundaries are usually a sign of weakening but this is not the case....this is an abnormal storm!

I think it IS the case. Clearly Chantal is struggling. So many outflow boundaries moving out away from the storm are not a sign of it becoming better organized. I'm not so sure it'll survive another 24 hours if the current forward speed doesn't decrease. And running into the DR won't help...

so I am not losing it! I was just going off the last RECON reports of falling pressures and higher winds...maybe the EURO was seeing something that the others were not..

its been doing this for 2 days now... you all seem to forget recon only been out of there for 2 hours and showed well defined circ and very tight pressure gradient as well as a wind profile that was a lot better than yesterday. looks can be deceiving...

[jlauderdal]

[quote="ROCK"]those outflow boundaries are usually a sign of weakening but this is not the case....this is an abnormal storm!

I think it IS the case. Clearly Chantal is struggling. So many outflow boundaries moving out away from the storm are not a sign of it becoming better organized. I'm not so sure it'll survive another 24 hours if the current forward speed doesn't decrease. And running into the DR won't help...

so I am not losing it! I was just going off the last RECON reports of falling pressures and higher winds...maybe the EURO was seeing something that the others were not..

its been doing this for 2 days now... you all seem to forget recon only been out of there for 2 hours and showed well defined circ and very tight pressure gradient as well as a wind profile that was a lot better than yesterday. looks can be deceiving...[/quote]
No access to ir would do this board some good at times

[cycloneye]

Dr Jeff Masters did a very long and interesting discussion this afternoon about Chantal.

Unusual Tropical Storm Chantal has strengthened a bit more as it speeds west-northwestwards at 29 mph away from the the Lesser Antilles Islands. Sustained winds of 38 mph, gusting to 52 mph, were observed at Martinique at 10 am AST as the storm passed. However, an automated weather station at the airport measured sustained winds of 60 mph, gusting to 78 mph, according to an official with Meteo-France. The Associated Press reported that Chantal ripped the roofs off of several homes on neighboring Dominica. An Air Force hurricane hunter aircraft measured top winds at their 1,000' flight level of 89 mph at 12:55 pm AST. Top winds seen by the aircraft's SFMR instrument were about 65 mph, in a small area east of Chantal's center. The Hurricane Hunters have departed Chantal, and the next plane is due in the storm at 8 pm EDT. Chantal's winds are unusually high considering the storm's high central pressure of 1006 mb and disorganized appearance on satellite imagery. Chantal is fighting dry air associated with the Saharan Air Layer (SAL), as seen on water vapor satellite loops. This dry air is creating strong thunderstorm downdrafts that are robbing Chantal of moisture and energy. Visible satellite loops show the outflow boundaries of these thunderstorm downdrafts at the surface, spreading to the northwest of Chantal. Martinique Radar shows a large area of heavy rain that is not well-organized, lying mostly to the west of the Lesser Antilles Islands.


An small-scale easterly jet creating high shear in Chantal

Chantal is not very impressive on satellite images, with a modest amount of heavy thunderstorms that are not well-organized. Only a small amount of upper-level outflow is visible. The reason for Chantal's rather disorganized appearance can be found by looking at this morning's balloon sounding from Guadaloupe. This island was just northwest of the center of Chantal when the balloon was launched at 8 am EDT. The sounding showed typical easterly trade winds at the surface of 12 knots (14 mph.) However, the winds rose quickly aloft, with a jet of easterly winds of 35 - 53 knots between 800 - 600 mb (about 7,000 - 15,000'.) But, by the time the ballon hit 500 mb (18,000'), the winds had died down to 15 knots. A change of wind speed from 12 knots to 53 knots and back down to 15 knots from the surface to 500 mb is a tremendous amount of wind shear, which will make it very difficult for a tropical storm to keep the surface center aligned with the upper level center. The traditional measure of wind shear, the difference in wind between 200 mb and 850 mb, was 44 knots in this morning's Guadaloupe sounding, but was a much higher 56 knots from 200 mb to 700 mb. The powerful easterly wind jet was not apparent at any of the other balloon soundings this morning at adjacent islands (Barbados, Puerto Rico, Saint Martin), and demonstrates that there is a lot going on the atmosphere at small scales we cannot see which makes intensity forecasting of tropical cyclones very challenging. Thanks go to Jason Dunion of NOAA's Hurricane Research Division for pointing out this morning's interesting Guadaloupe sounding.

Forecast for Chantal

Chantal will have difficulty intensifying much more before hitting Hispaniola on Wednesday afternoon. In their 11 am EDT wind probability forecast, NHC gave Chantal a 29% chance of becoming a hurricane before hitting Hispaniola. Working against intensification will be the high wind shear from the strong mid-level easterly jet discussed above, plus the fast forward speed of the storm--tropical storms moving faster than 20 mph in the deep tropics usually have trouble intensifying. In addition, the Eastern Caribbean is an area where the trade winds accelerate, helping drive sinking air that discourages tropical storm intensification. Dry air will also slow down the intensification process. Interaction with the high mountains of Hispaniola and high wind shear may be able to destroy Chantal by Thursday. The 2 pm EDT Tuesday wind shear forecast from the SHIPS model calls for shear to rise to the high range, 20 - 35 knots, Tuesday night through Friday. On Saturday, when Chantal is expected to be in the Bahamas, moderate wind shear of 10 - 20 knots is predicted. If Chantal survives until Saturday, it will then have the opportunity to re-strengthen. The latest 12Z run of the European model (ECMWF) dissipates Chantal as it crosses Hispaniola. The 12Z run of the American GFS model has Chantal barely surviving.

Chantal's fast west-northwest forward speed of 29 mph will slow to 20 mph by Wednesday morning and then 10 mph by Thursday night, as the storm "feels" the presence of a trough of low pressure over the U.S. East Coast. This trough will steer Chantal to the northwest and then north-northwest across Hispaniola and into the Bahamas. The trough of low pressure pulling Chantal northwards is expected to lift out the the northeast over the weekend, leaving Chantal behind off the coast of Florida. High pressure will likely build in, potentially forcing Chantal westwards into the Florida or Southeast U.S. coast, with a possible Sunday landfall.

http://www.wunderground.com/blog/JeffMa ... #commentop