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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F5 time...
Member Since: March 10, 2006 Posts: 0 Comments: 10571
Quoting 175. Dakster:
Umm. The NHC may not buy the model shift just yet. They seem to move slowly and with an abundance of caution.


As they should. Nothing worse than having your rear handed to you and having to do an about face several hundred miles back in another direction.
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Do I see 65MPH Chantal and I was told they do not use the 5MPH winds it's either 60 or 70..... Can you help me out Taz

Tanks Taco :o)
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Quoting 179. MechEngMet:


Yes aware of that, so are the gas companies. Might this "tool" (the fed-gov just gave them) help them raise it just a bit before the evac gouging laws go into effect?


yes, but the energy price makers are not stupid. They already know and do it beforehand anyways.

Member Since: March 10, 2006 Posts: 0 Comments: 10571
Quoting 173. Luisport:
zerohedge‏@zerohedge3 min
U.S. IS RESPONDING TO A LOSS OF WELL CONTROL IN GULF OF MEXICO
zerohedge‏@zerohedge4 min
GULF SITE POSSIBLE SHEEN IS OVER 4 MILES WIDE BY 3/4 MILE LONG
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Quoting 162. MiamiHurricanes09:
A pretty decent leftward shift amongst most of the plots.



ewwww
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Quoting 156. 62901IL:

he meant when not where.
When they want to do.
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Quoting 159. Dakster:


That is illegal - many states, including Florida have anti-price gouging laws during emergencies. (Natural Disasters included) This even includes the evacuation time.

Florida sets up a hotline to report price gouging abuse. I am sure we will see that information posted should it become warranted.


Yes aware of that, so are the gas companies. Might this "tool" (the fed-gov just gave them) help them raise it just a bit before the evac gouging laws go into effect?
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Quoting 173. Luisport:
zerohedge‏@zerohedge3 min
U.S. IS RESPONDING TO A LOSS OF WELL CONTROL IN GULF OF MEXICO



Oh my *^&(*)&)(*&. Not another one.
Member Since: March 10, 2006 Posts: 0 Comments: 10571



you can clearly see a small weakness, will it still be there when she's in the bahama's is anyones guess
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176. SLU
The fast trades in the Caribbean are making Chantal look more like a squall line than a TS. It may even lose its LLC at this rate.

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Umm. The NHC may not buy the model shift just yet. They seem to move slowly and with an abundance of caution.
Member Since: March 10, 2006 Posts: 0 Comments: 10571
Chantal may be a gulf storm afterall.
Member Since: June 16, 2005 Posts: 0 Comments: 1412
zerohedge‏@zerohedge3 min
U.S. IS RESPONDING TO A LOSS OF WELL CONTROL IN GULF OF MEXICO
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San Juan
NEXRAD Radar

Base Reflectivity 0.50° Elevation
Range 248 NMI

A good squall is approaching from the Se..so it will only pick up,the winds.

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Quoting 151. DataNerd:
Convection is expanding in all quadrants and so is the size of the circulation. Hard to tell whats going on under there right now.


Of more interesting note is its moving almost due west. Wobbling between WNW and W for the last few hours.

Link


It will likely correct, but then again, the science is not perfected yet on predicting such storms' precise paths. It could change predictions tremendously if she turns more northerly, say, 100-200 miles more to the west than currently predicted, right? That would be just west of the tip of Florida instead of on the eastern tip of that state.
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NOT what we need. Most rivers in NC are already at flood stage.
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expect a noticable shift left
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What a mess. GFS suite still wants to go west on some runs and GFDL wants to go even further west a dissipate near jamaica.

In short we still have roughly 2 days of guidance and beyond that its anyone's guess.


If the pressure comes down some that would help.
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If the ULL moves out of the way what would that do for the forcast?

Any chance this thing never turns northerly and heads into the GOM.?
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Quoting 129. Patrap:
San Juan
NEXRAD Radar

Velocity Azimuth Display Wind Profile ° Elevation
Range 124 NMI




i just a wind gust of 39 mph in south east puerto rico, no rain, very breezy!
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Quoting 146. yannik29:
quick question...when does the next HH Aircraft takes off today?

It's said in the first paragraph in Dr M's blog.

"The Hurricane Hunters have departed Chantal, and the next plane is due in the storm at 8 pm EDT."

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if Chantal dont start turning soon PR may be out of the woods
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Quoting 158. rmbjoe1954:


i must have missed the 18Z..what shift was there?
A pretty decent leftward shift amongst most of the plots.

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Florida is disappearing slowly in the latest model runs. NHC is getting way out there too, lol.


Member Since: August 19, 2005 Posts: 5 Comments: 5452
Pretty sure Chantal is going to at least stay together until final landfall somewhere along the East Coast. The storm is ragged but has been able to hold on to higher winds and decent, albeit unorganized, convection. The models seem to not show less time spent over mountainous regions of Hispaniola, meaning the land disruption won't be as painful. I doubt it ever reaches hurricane strength, but it will be a rainmaker from Puerto Rico to the East Coast.

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Quoting 148. MechEngMet:


Oh dear GAWD! That's all we need. Now the FED GOV has given them an excuse to hike the gas/oil/energy prices even earlier. Get ready for $6.00 gas in an evacuation. sheesh.


That is illegal - many states, including Florida have anti-price gouging laws during emergencies. (Natural Disasters included) This even includes the evacuation time.

Florida sets up a hotline to report price gouging abuse. I am sure we will see that information posted should it become warranted.
Member Since: March 10, 2006 Posts: 0 Comments: 10571
Quoting 145. MiamiHurricanes09:
Interested to see the 5p.m. cone considering the 18z model shift.


i must have missed the 18Z..what shift was there?
Member Since: June 16, 2005 Posts: 0 Comments: 1412

Chantal winds about three hours ago.
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Quoting 152. prcane4you:
Maybe from San Francisco Intl.

he meant when not where.
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Quoting Tazmanian:



well well well look oh came out of hiding



hi ike
I was about to say the same thing Taz...
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Quoting 145. MiamiHurricanes09:
Interested to see the 5p.m. cone considering the 18z model shift.


Shouldn't be a drastic cone shift. A little further N, but nothing eye-popping. Not yet anyways.
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Maybe more rain in GA



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Quoting 146. yannik29:
quick question...when does the next HH Aircraft takes off today?
Maybe from San Francisco Intl.
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Convection is expanding in all quadrants and so is the size of the circulation. Hard to tell whats going on under there right now.


Of more interesting note is its moving almost due west. Wobbling between WNW and W for the last few hours.

Link
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Quoting 146. yannik29:
quick question...when does the next HH Aircraft takes off today?

8pm edt
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From NWS Charleston:

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MAIN FORECAST CHALLENGE THIS PERIOD IS WHAT HAPPENS TO TROPICAL
STORM CHANTAL. THE 12Z/09 GFS...ECMWF AND CANADIAN MODELS ARE IN
FAIRLY GOOD AGREEMENT TAKING THE SYSTEM FROM AROUND THE BAHAMAS
FRIDAY NIGHT TOWARD THE SC/GA COASTS SATURDAY...ALTHOUGH THEY ALL
DIFFER WITH RESPECT TO THE STRENGTH OF THE SYSTEM. THE CANADIAN HAS
PERSISTENTLY BEEN SHOWING A STRONGER SYSTEM MAKING LANDFALL ALONG
THE SC/GA COASTS SO IT MAY BE ON TO SOMETHING. HOWEVER...THERE IS
STILL QUITE A BIT OF UNCERTAINTY REGARDING HOW STRONG THE STORM WILL
BE AFTER HITTING HISPANIOLA AND THUS HOW DEEP OF ATMOSPHERIC FLOW IT
WILL BE STEERED BY. THE MORE NORTHERN TRACK TREND IS CERTAINLY
DISCONCERTING SO WE URGE EVERYONE ACROSS THE AREA TO PAY CLOSE
ATTENTION TO THIS SYSTEM THROUGH THE WEEKEND.

WHETHER CHANTAL REMAINS A NAMED STORM OR NOT THERE WILL STILL BE
QUITE A BIT OF RAINFALL ACROSS THE AREA THROUGH THE WEEKEND AND
POSSIBLY INTO EARLY NEXT WEEK GIVEN THE DEEP TROPICAL MOISTURE
MOVING IN AHEAD OF AN APPROACHING/WEAKENING COLD FRONT WHICH WILL
STALL OUT OVER THE AREA. SEVERAL INCHES OF RAINFALL COULD OCCUR
THROUGH THE PERIOD...WITH EVEN MORE RAINFALL POSSIBLE IN ISOLATED
SPOTS AND ESPECIALLY IF CHANTAL MOVES DIRECTLY TOWARD THE AREA.
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Quoting 122. nrtiwlnvragn:
This Hurricane Season Energy Traders Have New Forecast Tool

Excerpt:

The Department of Energy has just released a nifty new tool energy-market watchers may find useful this hurricane season.

It contains real-time information on tropical storms from the National Hurricane Center overlaid on a map of major U.S. energy infrastructure sites, including oil and gas rigs in the Gulf of Mexico, oil import sites, oil refineries, power plants and other facilities.


Oh dear GAWD! That's all we need. Now the FED GOV has given them an excuse to hike the gas/oil/energy prices even earlier. Get ready for $6.00 gas in an evacuation. sheesh.
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Quoting 144. hu2007:
waiting for action here in pr xD CHANTAL

It waits for you...
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quick question...when does the next HH Aircraft takes off today?
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Interested to see the 5p.m. cone considering the 18z model shift.
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waiting for action here in pr xD CHANTAL
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143. auburn (Mod)
Quoting 128. PalmBeachWeather:
Clapton joined him (Yardbirds) Jimmy Page was in the audience


Please stay on topic or take it to another blog.Thanks.
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Quoting 140. Dakster:
Homedepot is up in trading today too. Think that has anything to do with an anticipated US Landfalling Hurricane?
They got wood
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Homedepot is up in trading today too. Think that has anything to do with an anticipated US Landfalling Hurricane?
Member Since: March 10, 2006 Posts: 0 Comments: 10571
139. whitewabit (Mod)
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Quoting 134. nrtiwlnvragn:


That has been going on already for as long as Energy Traders have existed.


But nothing like a visual to further induce disillusional behavior ;)
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Quoting 130. daddyjames:


So th einflated panic that occurs on this blog will now be out-matched by the inflated panic in the marketplace? Fantastic. ;)


Seems as though the oil companies have managed to jack up prices pretty well on their own without the tool. Any Gulf action becomes an excuse to worry about its effect on refineries, rigs, etc.
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Quoting 128. PalmBeachWeather:
Clapton joined him (Yardbirds) Jimmy Page was in the audience


What's this? I gotta get out more.
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About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.