July hurricane outlook

By: Dr. Jeff Masters , 7:26 PM GMT on July 02, 2009

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Atlantic tropical cyclone activity typically picks up a bit during the first half of July. Since the current active hurricane period began in 1995, seven of 14 years (50%) have had a named storm form during the first half of July. The busiest first half of July occurred in 2005, when three hurricanes formed. These included Hurricane Dennis and Hurricane Emily--the strongest hurricanes ever observed so early in the season. As seen in Figure 1, most of the early July activity occurs in the Gulf of Mexico, Western Caribbean, and Carolina waters. However, a few long-track "Cape Verdes" hurricanes begin to occur. These are spawned by tropical waves that come off the coast of Africa. Tropical waves serve as the instigators of about 85% of all major hurricanes. Last year's Hurricane Bertha was one such rare early July Cape Verdes hurricane. Bertha's 120 mph winds made it the sixth strongest early-season Atlantic hurricane on record. Bertha also set the record for farthest east formation as a tropical storm, hurricane, and major hurricane, so early in the season.


Figure 1. Tracks of all tropical storms and hurricanes 1851 - 2006 that formed July 1-15. North Carolina and the Gulf of Mexico coast from the Florida Panhandle to Texas are the preferred strike locations. Oddly, the Florida Peninsula has been struck by only two storms that formed in the first half of July.

Sea Surface Temperatures
Sea Surface Temperatures (SST) anomalies have warmed slightly over the past two weeks, but are close to average over the tropical Atlantic between Africa and Central America (Figure 2). These are the are the coolest SST anomalies we've seen since 1994. The strength of the Azores-Bermuda high has been near average over the past two weeks, driving near-average trade winds. Stronger-than-average trade winds were observed through most of the period November 2008 - May 2009, which helped cool the tropical Atlantic substantially. Strong winds mix up colder water from the depths and cause greater evaporative cooling. The latest 2-week run of the GFS model predicts continued average-strength trade winds through mid-July, so SSTs should remain near average during this period.

Typically, July tropical storms form over the Gulf of Mexico, Western Caribbean, and Gulf Stream waters just offshore Florida. SSTs are about 1.0°C above average for this time of year in the Gulf of Mexico, but near average elsewhere. July storms typically form when a cold front moves off the U.S. coast and stalls out, with the old frontal boundary serving as a focal point for development of a tropical disturbance. There will be one or two fronts moving off the U.S. coast over the next two weeks, and we will need to watch these for development. Wind shear is too high and SSTs are usually too cold in July to allow African tropical waves to develop into tropical storms. African tropical waves serve as the instigators of about 85% of all major hurricanes,

Figure 2. Sea Surface Temperature (SST) departure from average for July 2, 2009. SSTs were near average over the tropical Atlantic's Main Development region for hurricanes, from Africa to Central America between 10° and 20° North Latitude. Note the large region of above average SSTs along the Equatorial Pacific off the coast of South America, the hallmark of a developing El Niño episode. Image credit: NOAA/NESDIS

El Niño
El Niño conditions continue to amplify over the tropical Eastern Pacific. Ocean temperatures there rose 0.5°C over the past two weeks, and are now 0.45°C above the threshold for El Niño, according to the Australian Bureau of Meteorology (Figure 3). NOAA's Climate Prediction Center issued an El Niño Watch in early June, saying "that conditions are favorable for a transition from neutral to El Niño conditions during June - August 2009". The pattern of changes in surface winds, upper-level winds, sea surface temperatures, and deeper water heat content are all consistent with what has been observed during previous developing El Niños, and latest set of mid-June runs of the El Niño computer models are almost universally calling for El Niño conditions to become well-established for the peak months of hurricane season, August - October. It is likely that Atlantic hurricane activity will be suppressed in 2009 due to the strong upper-level winds and resulting wind shear an El Niño event usually brings to the tropical Atlantic.


Figure 3. Sea Surface Temperature (SST) departure from average for the the equatorial Eastern Pacific (the area 5°N - 5°S, 120°W - 170°W, also called the "Niña 3.4 region"). El Niño conditions exist when the SST in this region rises 0.5°C above average. As of June 28, 2009, SSTs in the Niño 3.4 region had risen to 0.95°C above average. To be considered an "El Niño episode", El Niño conditions must occur for five consecutive months, using 3-month averages. Image credit: Australian Bureau of Meteorology.

Wind shear
Wind shear is usually defined as the difference in wind between 200 mb (roughly 40,000 foot altitude) and 850 mb (roughly 5,000 foot altitude). In most circumstances, wind shear above 20 knots will act to inhibit tropical storm formation. Wind shear below 12 knots is very conducive for tropical storm formation. High wind shear acts to tear a storm apart. The jet stream's band of strong high-altitude winds is the main source of wind shear in July over the Atlantic hurricane breeding grounds, since the jet is very active and located quite far south this time of year.

The jet stream over the past two months has been locked into a pattern where a southern branch (the subtropical jet stream) brings high wind shear over the Caribbean, and a northern branch (the polar jet stream) brings high wind shear offshore of New England. This often leaves a "hole" of low shear between the two branches off the coast of North Carolina, which is where Tropical Depression One formed at the end of May.

The jet stream is forecast (Figure 4) to maintain this two-branch pattern over the coming two weeks. This means that the waters offshore of the Carolinas are the most likely place for a tropical storm to form during this period.


Figure 4. Wind shear in m/s between 200 mb and 850 mb, as forecast by the 06Z July 02, 2009 run of the GFS model. The position and strength of the subtropical jet stream is forecast to change little over the next two weeks, and this jet will bring high wind shear to the Caribbean and Gulf of Mexico into mid-July. There will at times be a region of low shear between the polar jet (northern set of arrows on the plots) and the subtropical jet, allowing for possible tropical development off the coast of North Carolina. Wind speeds are given in m/s; multiply by two to get a rough conversion to knots. Thus, the red regions of low shear range from 0 - 16 knots.

Dry air and African dust
June and July are the peak months for dust coming off the coast of Africa, and the Saharan dust storms have been quite active over the past month. Expect dust from Africa to be a major deterrent to any storms that try to form between Africa and the Lesser Antilles Islands in July.

Steering currents
The steering current pattern over the past few weeks has not changed much, and is typical for June and July. We have an active jet stream bringing many troughs of low pressure off the East Coast of the U.S. These troughs are frequent enough and strong enough to recurve any tropical storms or hurricanes that might penetrate north of the Caribbean Sea. Steering current patterns are predictable only about 3 - 5 days in the future, although we can make very general forecasts about the pattern as much as two weeks in advance. At present, it appears that the coming two weeks will maintain the typical July pattern, bringing many troughs of low pressure off the East Coast capable of recurving any July storms that might form. There is no telling what might happen during the peak months of August, September, and October--we might be in for a repeat of the favorable 2006 steering current pattern that recurved every storm out to sea--or the unfavorable 2008 pattern, that steered Ike and Gustav into the Gulf of Mexico.

Summary
Recent history suggests a 50% chance of a named storm occurring in the first half of July. Given that none of the computer models are forecasting tropical storm formation in the coming seven days, and SST and wind shear patterns look pretty average, I'll go with a 20% chance of a named storm forming during the first half of July.

Vote for Mike Theiss as an Antarctica blogger
Extreme weather photographer Mike Theiss, who wrote our Ultimate Chase photography blog for two years until a new job took him to South America, wants your help. He's entering a Quark Expeditions competition to receive an expense-paid 2-week trip to Antarctica, where he will do some intensive photography and blogging. In order to go, he needs the votes to show that he's a popular blogger. So, if you liked his posts while he was blogging for wunderground, and want to see him blog for wunderground during this potential Antarctica voyage, go to http://www.blogyourwaytoantarctica.com/blogs/view /220 and cast a vote. It takes about 3 minutes navigate through the registration and voting process. Mike will be back chasing hurricanes this August, and has promised to post his excellent storm photos on wunderground should we help him secure the Antarctica gig.

Have a great holiday weekend, and I'll be back Monday with a new post.

Jeff Masters

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2197. Patrap
.."I gotta tell ya Folks,this Wave is Impressive for early July"..

..Back to you in the Studio.

Member Since: July 3, 2005 Posts: 426 Comments: 129093
2196. scott39
Thanks levi i learned something. would you say this wave is toast, or if not what would you give it % wise in next couple of days?
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2195. Levi32
Quoting stillwaiting:
the area to watch for the possiblity of a new invest over the next 36hrs would be the area off the hondurous/nicaruaga border in the SW carib.,almost the same set up as a week ago.....


Not really. 93l formed from a mid-level low that moved north from the eastern pacific and interacted with a tropical wave that was much farther north than the current wave near the Nicaraguan coast. It will be in the eastern Pacific within 36 hours where it has better chances to develop.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The only area where I think we could see anything of remote interest over the next week will be off the SE US coast as old fronts get dragged through there. We could get cyclogenesis at the tail-end of those fronts and depending on how things evolve we might see something try to go warm-core.
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Quoting Drakoen:
Nothing is going to form over the next 10 days. Enjoy your week.


Yeah, I'm not really looking for tropical cyclogenesis until near the end of the month, when the next surge of moisture associated with the upward MJO pulse enters the basin.
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Quoting Patrap:
Hah,..those swilly Bloggers,they hav no Idea that the NHC is on my Side now.

Team WUBA cant find a INvest no where.

Swilly Bloggers.

Proceed wit da plan.

Is that Ed Rappaport ?
Member Since: Posts: Comments:
2191. Levi32
Quoting KoritheMan:
Think about it guys. This wave is moving around 30 mph, so even if upper-level conditions were ideal (which they clearly aren't, and like I said earlier, shear is only going to become briefly favorable to marginally favorable for tropical cyclogenesis in the Gulf of Mexico starting around 72 hours before it increases again with the approach of another trough), this wave would have a very hard time developing. Fast moving tropical waves have a notorious reputation for failing to significantly organize. In fact...

ZCZC MIATCPAT4 ALL
TTAA00 KNHC DDHHMM
BULLETIN
TROPICAL STORM CHANTAL SPECIAL ADVISORY NUMBER 7
NATIONAL WEATHER SERVICE MIAMI FL
8 PM AST THU AUG 16 2001

...CHANTAL BECOMING A TROPICAL WAVE...

AT 8 PM AST...0000Z...ALL WATCHES AND WARNINGS ARE DISCONTINUED FOR
THE ISLANDS OF THE LESSER ANTILLES BY THEIR RESPECTIVE
GOVERNMENTS...EXCEPT THE TROPICAL STORM WATCH FOR MARTINIQUE AND
GUADELOUPE WHICH WILL BE DISCONTINUED AT 8 AM AST TOMORROW.

REPORTS FROM AN AIR FORCE HURRICANE HUNTER PLANE INDICATE THAT
CHANTAL NO LONGER HAS A CENTER OF CIRCULATION...AND THE SYSTEM IS
BECOMING A STRONG TROPICAL WAVE.

AT 800 PM AST...0000Z...THE DISSIPATING CENTER OF TROPICAL STORM
CHANTAL WAS ESTIMATED IN THE VICINITY OF LATITUDE 13.0 NORTH...
LONGITUDE 61.0 WEST OR NEAR ST. VINCENT IN THE WINDWARD ISLANDS.

THE WAVE IS MOVING WESTWARD NEAR 29 MPH...47 KM/HR...AND A RAPID
WESTWARD MOTION IS EXPECTED TO CONTINUE FOR THE NEXT DAY OR SO.

MAXIMUM SUSTAINED WINDS ARE NEAR 40 MPH... 65 KM/HR...IN A FEW
SQUALLS.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 115 MILES
...185 KM FROM THE CENTER.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 1011 MB...29.85 INCHES.

RAINFALL AMOUNTS OF 2 TO 4 INCHES...WITH LOCALLY HIGHER AMOUNTS
IN MOUNTAINOUS AREAS...ARE STILL POSSIBLE OVER SOME OF THE LESSER
ANTILLES.

REPEATING THE 800 PM AST POSITION...13.0 N... 61.0 W. MOVEMENT
TOWARD...WEST NEAR 29 MPH. MAXIMUM SUSTAINED WINDS... 40 MPH.
MINIMUM CENTRAL PRESSURE...1011 MB.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITOR
PRODUCTS ISSUED BY YOUR LOCAL WEATHER OFFICE.

THIS IS THE LAST PUBLIC ADVISORY ISSUED BY THE NATIONAL HURRICANE
CENTER ON CHANTAL UNLESS REGENERATION OCCURS.

FORECASTER PASCH


NNNN


None of these waves are going to have a good shot at tropical cyclogenesis as long as they continue to move that quickly, even if the upper winds are favorable. If the trade winds slacken off some, then they will have a better chance at developing, but until then...


Exactly, that's why I don't give this wave much of a chance. Easterly trades are very strong right now screaming through the Caribbean and that ruins surface convergence. I don't see any tropical waves developing in there anytime soon. We would need a system to develop east of the islands first and then move into the Caribbean, but at this time of year that is also unlikely. Tropics south of 20N are shut down for the moment.
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From the Houston/Galveston NWS earlier discussion....


The last time the high temperature failed to exceed 95 degrees at
iah was June 8th.

And the drought continues. Issued a new dgthgx (drought statement) last night. Many climate and supplemental sites have
received less than 10 percent of the normal rainfall expected
since may 1st. Folks...it is as dry as I have ever seen it here.
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Quoting Drakoen:
Nothing is going to form over the next 10 days. Enjoy your week.
You are just being conservative :)
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2188. Patrap
Thank you O' mighty oracle...2186

Member Since: July 3, 2005 Posts: 426 Comments: 129093
the area to watch for the possiblity of a new invest over the next 36hrs would be the area off the hondurous/nicaruaga border in the SW carib.,almost the same set up as a week ago.....
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2186. Drakoen
Nothing is going to form over the next 10 days. Enjoy your week.
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2185. scott39
Hunkerdown i never questioned the nhc ability to forecast. i just said they in so many words were being more concervative.to your comment that some people think they can forcast better than the nhc. well now thats just silly. LOL
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Think about it guys. This wave is moving around 30 mph, so even if upper-level conditions were ideal (which they clearly aren't, and like I said earlier, shear is only going to become briefly favorable to marginally favorable for tropical cyclogenesis in the Gulf of Mexico starting around 72 hours before it increases again with the approach of another trough), this wave would have a very hard time developing. Fast moving tropical waves have a notorious reputation for failing to significantly organize. In fact...

ZCZC MIATCPAT4 ALL
TTAA00 KNHC DDHHMM
BULLETIN
TROPICAL STORM CHANTAL SPECIAL ADVISORY NUMBER 7
NATIONAL WEATHER SERVICE MIAMI FL
8 PM AST THU AUG 16 2001

...CHANTAL BECOMING A TROPICAL WAVE...

AT 8 PM AST...0000Z...ALL WATCHES AND WARNINGS ARE DISCONTINUED FOR
THE ISLANDS OF THE LESSER ANTILLES BY THEIR RESPECTIVE
GOVERNMENTS...EXCEPT THE TROPICAL STORM WATCH FOR MARTINIQUE AND
GUADELOUPE WHICH WILL BE DISCONTINUED AT 8 AM AST TOMORROW.

REPORTS FROM AN AIR FORCE HURRICANE HUNTER PLANE INDICATE THAT
CHANTAL NO LONGER HAS A CENTER OF CIRCULATION...AND THE SYSTEM IS
BECOMING A STRONG TROPICAL WAVE.

AT 800 PM AST...0000Z...THE DISSIPATING CENTER OF TROPICAL STORM
CHANTAL WAS ESTIMATED IN THE VICINITY OF LATITUDE 13.0 NORTH...
LONGITUDE 61.0 WEST OR NEAR ST. VINCENT IN THE WINDWARD ISLANDS.

THE WAVE IS MOVING WESTWARD NEAR 29 MPH...47 KM/HR...AND A RAPID
WESTWARD MOTION IS EXPECTED TO CONTINUE FOR THE NEXT DAY OR SO.

MAXIMUM SUSTAINED WINDS ARE NEAR 40 MPH... 65 KM/HR...IN A FEW
SQUALLS.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 115 MILES
...185 KM FROM THE CENTER.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 1011 MB...29.85 INCHES.

RAINFALL AMOUNTS OF 2 TO 4 INCHES...WITH LOCALLY HIGHER AMOUNTS
IN MOUNTAINOUS AREAS...ARE STILL POSSIBLE OVER SOME OF THE LESSER
ANTILLES.

REPEATING THE 800 PM AST POSITION...13.0 N... 61.0 W. MOVEMENT
TOWARD...WEST NEAR 29 MPH. MAXIMUM SUSTAINED WINDS... 40 MPH.
MINIMUM CENTRAL PRESSURE...1011 MB.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITOR
PRODUCTS ISSUED BY YOUR LOCAL WEATHER OFFICE.

THIS IS THE LAST PUBLIC ADVISORY ISSUED BY THE NATIONAL HURRICANE
CENTER ON CHANTAL UNLESS REGENERATION OCCURS.

FORECASTER PASCH


NNNN


None of these waves are going to have a good shot at tropical cyclogenesis as long as they continue to move that quickly, even if the upper winds are favorable. If the trade winds slacken off some, then they will have a better chance at developing, but until then...
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2183. Levi32
Quoting scott39:
levi please explain to me in layman terms, why i am being fooled by my eyes.


My post #2116:

Quoting Levi32:
Let me try explaining this. Look at the upper winds. There is a TUTT (basically upper trough) positively tilted through the Central Caribbean and extending north of Hispaniola. Look on the east side of this trough near and north of Hispaniola and Puerto Rico. See the batch of strong wind barbs pointing NE? That is creating upper divergence over the tropical wave that is taking air out of the top of the system. Since air is being taken out of the top air has to rise from the bottom to replace it. The rising air condenses and forms all those thunderstorms that makes it look so menacing. At the same time there is 30-40 knots of shear over the entire central/eastern Caribbean due to the upper trough. Just because a tropical wave has thunderstorms doesn't always mean it is a threat to develop. In this case it is not, at least for the next 2-3 days.


To add to that, even though the divergence aloft is enhancing thunderstorm activity, the shear that accompanies it is causing t-storms to collapse, come back in another area, collapse, pop up again, etc...the cycle never ends because the tops of the thunderstorms get blown apart by the shear. You need sustained convection that is allowed to grow, which requires light winds aloft (light wind shear). Once you get that, you can get a surface low and a more organized system. Right now this tropical wave is not organized. It is a well-defined wave but until it gets into a more favorable environment aloft that is all it will be, and a rainmaker for Caribbean countries.
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Quoting Levi32:


No I have not seen an invest put on any system like this. You're going on looks alone and ignoring the actual anatomy of the system.
People, please have some sense and listen to Levi. He has been repeating himself for at least three pages now explaining in simple terms WHY the tropical wave is not named, an invest, and not developing.

Please do a little research and you will see the large numbers of t-waves that transverse the Atlantic in every season and the majority never become anything more that what they are, a t-wave, regardless of the amount of awe-inspiring convection they may contain.
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Quoting KEEPEROFTHEGATE:


a little pop up

25.6n/39.9w
Looks more like Casper the Ghost waving at us.
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2180. scott39
levi please explain to me in layman terms, why i am being fooled by my eyes.
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Quoting scott39:
Ive seen the nhc put an invest on worst looking developing garbage then this one in the carrb.They do not want to lose thier credibility any more than they have,after the 93L fizzle!
Yeah, cause an ULL did not move the way some of the models predicted, the NHC lost credibility...NOT ! Not all numbered invests develop, as a matter of fact, the percentages are higher that dont. The NHC has not lost, and will not lose credibility except by some of the people on here who feel they know more and can do a better job of forcasting.
Member Since: Posts: Comments:
2178. Patrap
Hah,..those swilly Bloggers,they hav no Idea that the NHC is on my Side now.

Team WUBA cant find a INvest no where.

Swilly Bloggers.

Proceed wit da plan.

Member Since: July 3, 2005 Posts: 426 Comments: 129093
2177. Levi32
Quoting scott39:
Ive seen the nhc put an invest on worst looking developing garbage then this one in the carrb.They do not want to lose thier credibility any more than they have,after the 93L fizzle!


No I have not seen an invest put on any system like this. You're going on looks alone and ignoring the actual anatomy of the system.
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2176. KEEPEROFTHEGATE (Mod)


a little pop up

25.6n/39.9w
Member Since: July 15, 2006 Posts: 175 Comments: 54847
2175. scott39
Ive seen the nhc put an invest on worst looking developing garbage then this one in the carrb.They do not want to lose thier credibility any more than they have,after the 93L fizzle!
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Well good night all and to those Floridians who come on here waiting for a storm to develop.Im Floridian but will take whatever comes.Don't worry shear models are projected to drop a bunch in the next few weeks.Enjoy!
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Quoting tennisgirl08:
I know the NHC are the experts, but we have a clear TD or STD in the Atlantic - not labeled. And a very well-defined wave in the caribbean, that IMO, should be coded yellow. I am confused! They are sure being conservative. I know they must have their reasons, though.
They are not being conservative, you are wishcasting based on a picture you see. In both cases, the facts are that neither a name/classification nor a color code are warranted.
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Quoting Acemmett90:
however unless the carib wave gains more vorctiy i will only watch it with the corner of my eye
Hence the reason you thought it was moving north.
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2171. Patrap

Currently Active Tropical Cyclones,RAMMB


Last Updated 13 Minutes Ago
Member Since: July 3, 2005 Posts: 426 Comments: 129093
2170. beell
gosh, all this talk about the TUTT enhanced activity and the shear and the slightly better short term conditions in the BOC seems familiar.

Make it rain in TX!

Good Night, all.
)
Member Since: September 11, 2007 Posts: 144 Comments: 16876
2169. Levi32
Quoting StormFreakyisher:
Shear below 20 knts will allow for tropical systems to develop.And with 5-10knt shear in the Western Carib. will allow us for something to watch in the near future and no that is not high shear.I don't know why you said that fsumet.


Well the reason there's low shear in the NW Caribbean is because the TUTT axis cuts through there. If you think about it, at the very center of a low, or the center of an axis where the wind changes direction sharply, the wind speed has to be near 0. At the axis of an upper trough the wind will be very light near the trough axis, but the upper trough isn't a favorable environment for a tropical disturbance to develop, so really there is no favorable conditions in the NW Caribbean right now. In 2-3 days the TUTT may lift far enough north to allow lighter winds aloft but still less-than-ideal for development. Like I said we'll keep an eye on it but development is unlikely.
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Quoting StormFreakyisher:

That's kinda harsh cause if this goes into Mexico and Belize, mudslides are a big problem there.I don't don't think it would be "good" if it went there.IN MY OPINION, I would let it come to Florida because we don't get mudslides and we are more safe with better protection.I am not saying Belize has bad storm protection but just not as imroved in some places there like here.


Ok, so that was harsh. I wish this wave would go POOF!

Quoting fsumet:


I edited what I said cause the far western/northwestern Carib does have lower shear. However, the wave will plow into the Yucatan or Belize and possibly has a chance to move into the far southern BOC. At best if we saw anything form in the southern BOC it would last about 5 minutes (exaggeration) before making landfall in Mexico lol


I agree!
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Good night
Member Since: June 29, 2009 Posts: 13 Comments: 5315
Shear below 20 knts will allow for tropical systems to develop.And with 5-10knt shear in the Western Carib. will allow us for something to watch in the near future and no that is not high shear.I don't know why you said that fsumet.
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2165. Levi32
Quoting fsumet:


I changed what I had in there. The far western/northwestern Carib has lower shear. However, the wave will plow into the Yucatan or Belize and possibly has a chance to move into the far southern BOC. At best if we saw anything form in the southern BOC it would last about 5 minutes (exaggeration) before making landfall in Mexico lol


Lol yeah.

The TUTT might pull out enough to allow lower shear in the western Caribbean but the upper environment will still be less than ideal. We'll see how the wave looks by the time it gets there but I personally think the low-level easterlies screaming through the Caribbean are enough all by themselves to keep this wave from developing.
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Quoting tennisgirl08:


Good! Then it will simply then become a problem for the EPAC, not us.

That's kinda harsh cause if this goes into Mexico and Belize, mudslides are a big problem there.I don't don't think it would be "good" if it went there.IN MY OPINION, I would let it come to Florida because we don't get mudslides and we are more safe with better protection.I am not saying Belize has bad storm protection but just not as imroved in some places there like here.
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2163. fsumet
Quoting tennisgirl08:


Good! Then it will simply then become a problem for the EPAC, not us.


I edited what I said about 30 seconds after cause the far western/northwestern Carib does have lower shear. I was looking more central as it should keep moving due west into Belize. However, it has a chance to move into the far southern BOC. At best if we saw anything form in the southern BOC it would last about 5 minutes (exaggeration) before making landfall in Mexico lol
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I'm still waiting for the first person to say its coming to Florida! lol
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Quoting tennisgirl08:
atmoaggie - nowhere near TD or TS status. But, are you saying that it should be labeled an invest at this point? Or not?


Barely... yes. But I reserve the right to revoke my support. 8-)
Member Since: August 16, 2007 Posts: 6 Comments: 12463
2160. KEEPEROFTHEGATE (Mod)


latest 10 58 pm edt
Member Since: July 15, 2006 Posts: 175 Comments: 54847
So, after all the points being made we have all come to the same conclusion! The wave should be watched!! LOL!!
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Quoting fsumet:


The western Carib has high shear as well. No, the shear will not kill the wave but it will not allow it to develop. Looking at the winds it should move west and into Central America somewhere near Belize.

Really?Look at the shear map here.
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Quoting fsumet:


The western Carib has high shear as well. No, the shear will not kill the wave but it will not allow it to develop. Looking at the winds it should move west into Belize.


Good! Then it will simply then become a problem for the EPAC, not us.
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2156. Levi32
Quoting tennisgirl08:
I see both Levi and FSUmet's points about the Caribbean wave. However, I do think this wave will be something to watch over the next few days. Tropical waves are not really affected by shear. So, moving through 30-40kts shouldn't kill it. Afterwards, it will be moving into a more favorable environment in the western caribbean, at which time, it will become an invest.

Hopefully it will keep moving west and make its way into the EPAC and form. And not drift NW into the GOMEX.


Well the tropical wave itself is not killed by shear but the thunderstorms can't organize in the face of shear and therefore a surface low can't form. The environment may be a little more favorable in the western Caribbean and southern Bay of Campeche in 2-3 days which is where this is going but we'll have to see. I think it's unlikely but it should be watched in case it tries to pull something.

Quoting StormFreakyisher:

But isnt that how we start tracking storms in the first place when they develop.So your saying it is not an area of interest like every other tropical wave that passes and sometimes develop BUT it is not an area of interest?Not to watch?


Sure all storms start from nothing, but in this situation it is not an organized tropical disturbance. The thunderstorms are not being generated by a warm-core feedback process (warm moist air over the ocean being lifted). They are being caused by divergence aloft. In this light it is just a well-defined tropical wave that right now is not showing signs of development, and likely won't as long as it is under 40kts of shear. The NHC doesn't put an invest on every strong wave they see. Strong waves have a better chance of developing but that doesn't mean they will. They still need a distinct set of conducive atmospheric conditions to develop.

Quoting tennisgirl08:


Thanks FSU met! I think Levi was getting very frustrated trying to explain it to us! LOL!!


Lol...no, I like trying to answer people's questions =) That doesn't mean everybody always pays attention though lol. As long as those thunderstorms last the wave will get hyped but that's ok. I'm just trying to help some people see what is actually going on.
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Quoting tennisgirl08:
I see both Levi and FSUmet's points about the Caribbean wave. However, I do think this wave will be something to watch over the next few days. Tropical waves are not really affected by shear. So, moving through 30-40kts shouldn't kill it. Afterwards, it will be moving into a more favorable environment in the western caribbean, at which time, it will become an invest.

Hopefully it will keep moving west and make its way into the EPAC and form. And not drift NW into the GOMEX.

FIANLLY!You have made my day.Tropical waves don't die out over shear because they keep on going and yes we should keep on watching it because it will be moving into a favorable environment once it gets through the worst.
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Quoting AllStar17:


Wow, email that to the NHC now! Wait until it actually gets into the WCAR before jumping to conclusions.


Just my opinion!! And, no, I am not wishcasting and hoping for a storm. This wave has just been very persistent for a long time and I don't think shear will kill it. By 2-3 days out it will be in more favorable conditions, and I will eat crow if it is not an invest at that point. We will see!!
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2153. fsumet
Quoting tennisgirl08:
I see both Levi and FSUmet's points about the Caribbean wave. However, I do think this wave will be something to watch over the next few days. Tropical waves are not really affected by shear. So, moving through 30-40kts shouldn't kill it. Afterwards, it will be moving into a more favorable environment in the western caribbean, at which time, it will become an invest.

Hopefully it will keep moving west and make its way into the EPAC and form. And not drift NW into the GOMEX.


The western Carib has high shear as well until the very far western to northwestern Carib. No, the shear will not kill the wave but it will not allow it to develop. Looking at the winds it should move west and into Central America somewhere near Belize.
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2152. beell
Does this look like an Invest?
Link
Member Since: September 11, 2007 Posts: 144 Comments: 16876
Shear may become favorable over the next three days or so, but after that, it quickly returns due to the approach of a mid- to upper-level trough. I don't think this wave has a chance if it moves into the Gulf of Mexico. Perhaps it will spawn off Blanca in the East Pacific if 94E doesn't do it first.
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Quoting tennisgirl08:
I see both Levi and FSUmet's points about the Caribbean wave. However, I do think this wave will be something to watch over the next few days. Tropical waves are not really affected by shear. So, moving through 30-40kts shouldn't kill it. Afterwards, it will be moving into a more favorable environment in the western caribbean, at which time, it will become an invest.

Hopefully it will keep moving west and make its way into the EPAC and form. And not drift NW into the GOMEX.


Wow, email that to the NHC now! Wait until it actually gets into the WCAR before jumping to conclusions.
Member Since: June 29, 2009 Posts: 13 Comments: 5315
atmoaggie - nowhere near TD or TS status. But, are you saying that it should be labeled an invest at this point? Or not?
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Quoting atmoaggie:


Watch it yes, but say it is a TD or TS and NHC is asleep at the wheel? If they were to call every wave that develops any convection a TS, the term TS loses meaning and the general populace grows complacent.

Not unlike a 70% false alarm rate for nadoes. I can tell ya, the city of Tulsa doesn't scurry in basements at the first alert of a nado warning...and ultimately will wish they had one day.

Why have any serious public announcements (i.e. forecast advisories, etc.) thus alerting the general public over a wave with no future? No good reason I can come up with. Until the threat is there for a system to have the potential to actually cause any damage, simply labeling it an invest and watching it further is plenty of action on it.


Well said
Member Since: October 1, 2007 Posts: 81 Comments: 26511

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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.