Unusual Chantal Disorganized, but has 65 mph Winds

By: Dr. Jeff Masters , 8:06 PM GMT on July 09, 2013

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Unusual Tropical Storm Chantal has strengthened a bit more as it speeds west-northwestwards at 26 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.


Figure 1. MODIS image of Chantal taken at approximately 1 pm EDT Tuesday, July 9, 2013. At the time, Chantal had top winds of 65 mph, but looked very disorganized, due to high wind shear and dry air. Dry air is creating strong thunderstorm downdrafts that are robbing Chantal of moisture and energy. Outflow boundaries from these downdrafts are spreading out to the northwest of Chantal, as seen on this satellite image. Image credit: NASA.

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 26 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.

Jeff Masters

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Quoting 2024. StormTrackerScott:
It's too early in the am for trolls. May have to get some troll repellent if this keeps up.


I need a case of repellent, where can I get some????
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2034. LargoFl
Quoting 2027. StormTrackerScott:
Folks don't count Chantal out yet as there is almost no shear close to fl. Chantal has been fighting some westerly shear the last 24 hours but once Chantal emerges in the sw Atlantic then conditions will be very favorable for regeneration.
yes and as it rides up the east coast of florida it gets into the warm gulfstream waters..NHC has it back to tropical storm about mid florida
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2033. KEEPEROFTHEGATE (Mod)
Quoting 2027. StormTrackerScott:
Folks don't count Chantal out yet as there is almost no shear close to fl. Chantal has been fighting some westerly shear the last 24 hours but once Chantal emerges in the sw Atlantic then conditions will be very favorable for regeneration.
don't tell sweetpie that I want him in that lawn chair
out front and centre just as it runs him over
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Chantal wanted to go over the less mountainous Central Cuba. Seems to be "trying" to make another comeback this morning. She's down but I sure wouldn't count her out. She is a tenacious little "B" and conditions could become very favorable once north of Cuba.

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2030. LargoFl
where's georgiastormz lately...he may want to see this track..
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Lol. GFS nothing for two weeks then this...that they lose the next frame. Patience will be in order. :)

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Quoting 2024. StormTrackerScott:
It's too early in the am for trolls. May have to get some troll repellent if this keeps up.

And a bunch of downcasters. Dealt with them all night.
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Folks don't count Chantal out yet as there is almost no shear close to fl. Chantal has been fighting some westerly shear the last 24 hours but once Chantal emerges in the sw Atlantic then conditions will be very favorable for regeneration.
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It's too early in the am for trolls. May have to get some troll repellent if this keeps up.
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2023. LargoFl
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Good morning all.

I have to say I had no intention of being awake at this hour... lol... however the thunder woke me up. Seems the western edge of the ULL is kicking up a storm or two.

I think this ULL has been a kink in the NHC forecast, since its behaviour has been more difficult to forecast than Chantal's the last couple of days. I expected it would have scooted over into the GoM by now, but it seems it will be still drifting over the Keys tomorrow.

Furthermore, instead of Chantal slowing down, I see it has sped up! No wonder it's the next best thing to an open wave. And with the high as strong as it is, it's starting to look like Chantal may be a Brownsville darling after all.

We'll see if Chantal falls in behind the upper trough and turns up along the FL coast. That GA landfall is unusual, even in a forecast. I gotta say, just about the only place that is more overdue for a landfalling storm than FL is GA... be interesting if Chantal does end up there, and then sets a trend for landfall in that area...
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2020. LargoFl
Quoting 2016. jeffreeysweetypie:
like i said our daily t storms are far far worse then what chantal will bring we want to trade
yeah last night we had an amazing thunder and continous Lightning storm..just kept on going for hours here on the coast.
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Good morning to all,evening Aussie.

The models don't have anything of significance in the short/medium range so we may have to wait a while for the next development.
Member Since: April 29, 2009 Posts: 75 Comments: 14000
2017. WxLogic
Good Morning... Hope Chantal doesn't pull a Fay LOL...
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2015. KEEPEROFTHEGATE (Mod)
Quoting 2013. jeffreeysweetypie:
we are all prepared for 10 mph winds and drizzle here dont worry we will hunker down


maybe set up a lawn chair out front so you can see it approach
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2014. LargoFl
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
538 AM EDT WED JUL 10 2013

FLZ039-042-043-048>052-055>057-060>062-065-GMZ830 -850-853-856-870-
873-876-110100-
LEVY-CITRUS-SUMTER-HERNANDO-PASCO-PINELLAS-HILLSB OROUGH-POLK-
MANATEE-HARDEE-HIGHLANDS-SARASOTA-DESOTO-CHARLOTT E-LEE-
TAMPA BAY WATERS-TARPON SPRINGS TO SUWANNEE RIVER OUT 20 NM-
ENGLEWOOD TO TARPON SPRINGS OUT 20 NM-
BONITA BEACH TO ENGLEWOOD OUT 20 NM-
TARPON SPRINGS TO SUWANNEE RIVER OUT 20 TO 60 NM-
ENGLEWOOD TO TARPON SPRINGS OUT 20 TO 60 NM-
BONITA BEACH TO ENGLEWOOD OUT 20 TO 60 NM-
538 AM EDT WED JUL 10 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WEST CENTRAL AND SOUTHWEST
FLORIDA.

.DAY ONE...TODAY AND TONIGHT.

...THUNDERSTORM IMPACT...
SCATTERED TO NUMEROUS MAINLY AFTERNOON AND EVENING THUNDERSTORMS
ARE EXPECTED TODAY. THESE THUNDERSTORMS WILL BE CAPABLE OF
PRODUCING HEAVY RAINFALL...GUSTY WINDS...AND FREQUENT LIGHTNING.

...WATERSPOUT IMPACT...
WATERSPOUTS ARE POSSIBLE ALONG THE COAST TODAY. MARINERS AND THOSE
ALONG THE COAST SHOULD REMAIN VIGILANT AND BE PREPARED TO ACT TO
REACH SAFETY IN CASE OF A LANDFALLING WATERSPOUT THREAT.

...RIVER FLOOD IMPACT...
A COUPLE OF AREA RIVERS REMAIN ABOVE FLOOD STAGE. ANY ADDITIONAL
RAINFALL COULD CAUSE A FURTHER INCREASE IN WATER LEVELS AND MORE
PRONOUNCED FLOODING ALONG THE RIVERS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

...THUNDERSTORM IMPACT...
SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS ARE EXPECTED
EACH DAY. THE STRONGEST STORMS WILL BE CAPABLE OF PRODUCING HEAVY
RAINFALL...GUSTY WINDS...AND FREQUENT LIGHTNING.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS SHOULD MONITOR THE WEATHER AND SELF ACTIVATE IF NEEDED.

$$

GARCIA
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2011. KEEPEROFTHEGATE (Mod)
Quoting 2007. jeffreeysweetypie:
Our local mets on channel 13 here in florida just said on the tropical update, that now is the time to prepare for a tropical depression or tropical wave thats comming this weekend...... now thats to funny , we are all going to board up for this monster of a wave
give yer head a shake
by being prepare means to expect periods of rain and breezy conditions to develop
as the system approaches
and expect such conditions for a period of time as it passes

you seem to be pushing a little drama here or maybe you have nothing better to do
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Quoting 2002. KEEPEROFTHEGATE:


don't worry
fla will be getting an ass whipping
in a really big way

lots of season yet to come

and there are plans for fla

this season


Plans? What plans?
I hope they're not plotting against us!
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Talked to Dr Louis Ucellini yesterday, doing climate work.

Was interesting....
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Quoting 2004. MahFL:
The shear tendency is still downwards for Chantal's path.


which is why i believe this WNW movement is just a jog.
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Palm Beach County residents Be Advised -

The PBC 'Evacuation Tool' via the PBC website, will ONLY work on Windows Explorer. I also have an issue where even on WE, my EZ is not identified.

The "Information Technology" team for PBC is attempting to fix the first issue, and is "looking into" the 2nd issue.

There is an app (Android and iPhone) called PBC DART that will ID EZ (along with some other nifty stuff). I have only found 1 error on the app (1 block off in north WPB EZ#2), and again, the IT team is "working on it."

A copy of the latest response from our Emergency Manager:

Rob Shelt C.
4:46 PM (13 hours ago)

Mike,
As a follow up, we will put language next to the link to the Evacuation Tool that Internet Explorer is required. I spoke to our Information Technology staff and the County designs programs to work on Internet Explorer.

As to the address lookup in Internet Explorer, the IT staff are still looking into this. I’ll let you know when I hear something.

Rob
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2005. barbamz

Have a good day everybody!
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2004. MahFL
The shear tendency is still downwards for Chantal's path.

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Quoting 1991. GetReal:



For those looking for the next model generated storm, you may have to wait a little longer than anticipated yesterday.


Going by the GFS anyway, the trades don't look to let up and give anything a foothold.
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2002. KEEPEROFTHEGATE (Mod)
Quoting 1999. jeffreeysweetypie:
Here in florida we would rather have chantal then our daily afternoon t storms.... our t storms are so much worse then what chantal will bring


don't worry
fla will be getting an ass whipping
in a really big way

lots of season yet to come

and there are plans for fla

this season
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Chantal looks gone on the GFS remnants look caught up in low level flow riding north over Fl. best I tell. But any farther south with that cutoff low and it will be tracking westward in the gulf.

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China just can't get a break this year (no pun intended). I hope the US's competitive spirit doesn't try to play catch-up with the 2013 Atlantic season.
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Quoting 1989. jeffreeysweetypie:
the way chantal keeps shifting west , if it even stays together it might hit mexico by friday///// does this sound familiar all week?

I'm still saying freeport.
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DMAX is helping our little storm that could...
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1993. barbamz
Good morning! Very bad pictures are arriving from China. I hope (the remnants of?) Chantal will behave better when crossing Haiti.

China Sichuan landslide 'buries up to 40 people'
BBC News with video: 10 July 2013 Last updated at 09:58 GMT

A landslide has buried between 30 and 40 people in China's Sichuan province, state media say.

The landslide occurred in Zhongxing town on Wednesday morning. More than 100 rescuers with rescue dogs were at the scene, Xinhua news agency said.

The landslide followed days of torrential rain across parts of China that has caused floods in some areas.

On Tuesday, a bridge in Sichuan's Jiangyou collapsed, with at least 12 people missing.

Footage from Chinese state media, meanwhile, showed the dramatic rescue of a Deyang factory worker, who was stranded by
the floods after the factory was washed away.
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1992. Kumo
Quoting 1977. bigwes6844:
k i couldnt find it on the map though




Pardon the sloppy editing, I just have paint on this PC.

http://i.imgur.com/mfFgyNg.jpg
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1991. GetReal



For those looking for the next model generated storm, you may have to wait a little longer than anticipated yesterday.
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1988. GetReal



Nothing much there ATT.
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Email me @ andrbrooks0@gmail.com to tell me we have a new AOI.
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1986. GetReal
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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