Wind shear decline expected across the atlantic basin....

[SouthFloridawx]

Looking at the GFS 300mb wind/heights for 12Z today, it looks like we'll be seeing a decrease in the short term rather than just 2 weeks out.

I'd say the area to watch during the next couple of weeks is the W and NW Caribbean.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... loop.shtml

http://cimss.ssec.wisc.edu/tropic/real- ... g8sht.html

[SouthFloridawx]

Also to note is the ridge in the West and How Troughiness heads up and around it and down into the East Coast. This could be particularly worrisome for the The E. GOM and the Southern East Coast. Systems would be pulled up from the Caribbean into the Gulf.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... loop.shtml" target="_blank

Note here the lowered Upper Level winds in the Caribbean.
http://www.fileden.com/files/18682/gfs_250_090l.gif" target="_blank

http://www.fileden.com/files/18682/gfs_500_090l.gif" target="_blank

[Tampa Bay Hurricane]

Intriguing models. Perhaps some additional
moisture may be pulled into the GOM down the
line...perhaps some rain...at the least...

[Cyclenall]

Cyclenall,

Weather patterns do oscillate (even the jetstream in it's own way, since it behaves hose-like), that's a given, so, hopefully if there's a change to low-shear, then, it'll reverse itself soon enough...

What do you mean by "hose like"? The jetstream looks like a hose but in what way does it shift that would be like a hose?

Guess if I lived where you live I'd be more interested in seeing a few big hurricanes, too...

Yes.

[wxman57]

Shear always decreases in July in the Atlantic Basin. That's why most storms form in late July through early October. If the GFS is correct, then it's showing a ridge gradually building across the west Atlantic with decreasing upper-level winds in most areas. Just what you'd expect over the next few weeks.

[miamicanes177]

Dr. Jeff Masters says this is very unusual to have wind shear at values the models are forecasting in July. He said it is something you would expect a month later, in August. He seems very concerned about this late breaking development. His forecast on monday will be very interesting indeed.

Dr. Masters in his own words: "All of the computer models are forecasting that the subtropical jet will weaken substantially over the next ten days, bringing much lower than average wind shear to the tropical Atlantic. It is normal to see the subtropical jet weaken in the summer, but it usually happens a month later than this--in August."

[Aric Dunn]

sounds like we need to watch for that to see if it pans out

it is interesting.. because that could possible mean some intense hurricane in july again

[Frank2]

Oops, Cyclenall - I meant that the jetstream does undulate hose-like...

[Cyclenall]

Oops, Cyclenall - I meant that the jetstream does undulate hose-like...

I understand it does that but I thought the Jetstream doesn't dip down until the winter "pattern" is established? That means it doesn't oscillate during the summer/fall season and follows a seasonal trend instead.

[Frank2]

True the seasonal dip of the northern jet usually means the end of the hurricane season, but, the sub-tropical jet is also bad news (or good news) when it comes to approaching tropical systems...

Hurricanes are powerful, but, they are weak in the knees when it comes to shear from any source...

[Cyclenall]

True the seasonal dip of the northern jet usually means the end of the hurricane season, but, the sub-tropical jet is also bad news (or good news) when it comes to approaching tropical systems...

Hurricanes are powerful, but, they are weak in the knees when it comes to shear from any source...

That makes much more sense now, thanks. One thing that has always fascinated me is how shear at a certain position of a storm can help it strengthen or even rapidly strengthen by ventilating it. In that case, it's good for the storm. Classic example is Tropical Storm Ernesto early on when it was still in the south Caribbean on August 25, 2006 (didn't rapidly strengthen but the ULL may have helped it more then hurt it). Another was Typhoon/Hurricane Ioke at one point.

[philnyc]

At the bottom of this page:
http://www.ssd.noaa.gov/PS/TROP/genesis.html" target="_blank
Is the current shear compared to normal for different regions. It has other genesis products on that page that are very informative.

Love that link. Thanks a lot for that!