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The 2017 Atlantic Hurricane Season Thread


George BM

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On 5/31/2017 at 10:02 PM, George BM said:

The GFS and some other models are hinting at some GOMEX mischief in the short/med range from TD Two-E's energy.

gfs-ememb_lowlocs_watl_16.png

www.tropicaltidbits.com

 

:thumbsup:

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45 minutes ago, Kmlwx said:

Not interested unless it's a pinhole eye cat 5 OR a big storm just to the west of us/the bay ;) 

Or an Ivan-esque tornado producer. 

If we get even a TS making landfall east of the MS river timed with an approaching front from the west we can have some fun with multiple EF0-1 quick hitting spinny things. And training rains of course. GFS/GEFS likes the idea of something running up the gulf but height pattern in the east is showing suppression depression for our area. I suppose it would be prudent to wait until a storm actually forms before thinking about that though. LOL 

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19 minutes ago, Bob Chill said:

If we get even a TS making landfall east of the MS river timed with an approaching front from the west we can have some fun with multiple EF0-1 quick hitting spinny things. And training rains of course. GFS/GEFS likes the idea of something running up the gulf but height pattern in the east is showing suppression depression for our area. I suppose it would be prudent to wait until a storm actually forms before thinking about that though. LOL 

I want 24 hours straight of tornado watches ;)

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22 hours ago, WxWatcher007 said:

This is my 12,000th post! 

Ok, for those of you who weren't here last season, I think we had a really nice thread for tropical weather, maybe the best on AmWx--especially during the down times. Many of you know that tropical season is my serious season (as opposed to the winter silly season) and I think the discussion we put together last season was of high quality, except for the typical banter sections that went off the rails and multiple threads tracking fails lol. 

We'll see what this season holds, but I think it could be the second consecutive year we see an uptick in activity. I think my forecast would track pretty closely with NOAAs late May outlook. I like what I see with regard to the SSTs, TCHP, and potential shear, but the biggest thing to me has been the trend away from a developing Nino, which tends to increase the amount of shear and dry air over the main development region (MDR). 

Just two months ago, the odds of a Nino developing were placed at 50%. Now, those probabilities have dropped to 39% during the peak of hurricane season (August, September, October). 

figure1.gif

Whether that gives us posters US threats to track remains to be seen. If we see persistent ridging (which has been hard to come by so far) over the northern Atlantic to provide blocking, that could increase the risk of landfalling systems. I think we're probably playing with an average risk during the season but that's a low skill forecast. 

---------------

Ok, all of that said I am starting to think we have our first real area of interest. All of the major operational guidance in "range" (Euro, GFS, Canadian:yikes:) have a sprawling area of activity in the far west Caribbean popping an area of low pressure by next Saturday. More importantly, both the EPS and GEFS have it too.

This far out, the details are meaningless but I think the overall pattern could support the development of a low in that region which consolidates a bit as it moves west or northwest. That's about as far as I think we're worth looking so far. 

We may see an uptick in overall tropical but so far I am not really liking what I see for potential in our region. Looking at the CANSIPS and CFS for July and August and the 500 mb doesn't look promising with the mean trough setting up in the east and little to no south Atlantic ridging to speak of. September is only marginally better with a less pronounced trough but it still lacks any south Atlantic ridging. And looking at both the GEFS and the EPS they are also moving towards reestablishing the troughiness in the east in the longer range.

In my mind, if the climate models are correct, the setup argues for predominately Caribbean and/or Gulf development with little to no action crossing the Atlantic from Africa. With any Caribbean development either moving into the gulf or those that do turn north being quickly shunted out to sea with little to no impact with eastern seaboard. Of course you could always get something to time right to give us a coastal impact in out general region but I would think the more likely scenario is to have a system impact the Gulf and then get swept up by a trough driving its remnants through the region.

*Looks as if the Enso models are now seeing a neutral for this winter.

 

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15 minutes ago, WxWatcher007 said:

Nice post. I'm not particularly fond of the seasonal guidance and I don't use it too much to gauge chances for EC strikes. For me, just I look for a sense of the broader environment to see whether the basin is active/inactive and then zoom in on the upper level pattern when something pops or appears likely to.

Given the persistence of the upper level pattern over the CONUS, I wouldn't be surprised to see east troughing remain dominant through the season (just in time to flip to a SE ridge for the winter lol), but as you said, all we need is a window, and I think there may be a couple if for no other reason than typical pattern oscillations and homebrew (my favorite). 

Remnants count as a win for me too :) 

Remnants are a 50/50 proposition with me. Some can be exciting with lots of rain, wind and hit and miss F0 and F1 spinups but others can be nothing more then your average rainy day. Then you have the grand daddy of them all. Agnes. Which was probably a top 5 weather experience for me.

Edit. Take the climate models with a grain of salt myself but I have to admit the Sips did a very good job last winter. See how it does this winter and I might have to reevaluate my thoughts on it. As far as the CFS that is another story.

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59 minutes ago, showmethesnow said:

Remnants are a 50/50 proposition with me. Some can be exciting with lots of rain, wind and hit and miss F0 and F1 spinups but others can be nothing more then your average rainy day. Then you have the grand daddy of them all. Agnes. Which was probably a top 5 weather experience for me.

Edit. Take the climate models with a grain of salt myself but I have to admit the Sips did a very good job last winter. See how it does this winter and I might have to reevaluate my thoughts on it. As far as the CFS that is another story.

Well........... As long as we stop getting "lefted" by them.

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000
ABNT20 KNHC 170554
TWOAT 

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Sat Jun 17 2017

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

A tropical wave located about 1600 miles east-southeast of the
southern Windward Islands is producing scattered showers and
thunderstorms.  This disturbance continues to show signs of
organization, and some additional development is possible
during the next couple of days before conditions become less
favorable for tropical cyclone formation. This system is expected
to continue moving toward the west at 15 to 20 mph over the
tropical Atlantic during the next several days.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...high...70 percent.

A broad trough of low pressure is producing a large area of
cloudiness and showers over most of Honduras and the northwestern
Caribbean Sea.  Conditions appear to be favorable for gradual
development of this large disturbance while it moves slowly
northwestward across the Yucatan Peninsula this weekend and into
the south-central Gulf of Mexico early next week.  Regardless of
development, heavy rains are likely to spread over portions of
Central America, the Yucatan Peninsula, and western Cuba during
the next several days.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...high...70 percent.

$$
Forecaster Stewart
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5 hours ago, WxWatcher007 said:

Not hard to see why the NHC has gone up on the odds over time. The environment has continued to become more favorable, and in response, we have a broad low that has developed to the north and east of Honduras and Belize. Looking at the wind analysis, it is broad, but it's there. Right on schedule. 

I can't recommend the GOM view of GOES-16 enough. We're getting our first look at exceptional satellite resources being put to work for tropical. 

gulf_02_20170617175718.jpg

gulf_10_20170617175718.jpg

gulf_13_20170617175718.jpg

 

Overall, the analysis hasn't changed all that much. We're still waiting to see how the evolution of the low proceeds. It looks like shear is diminishing over the region, which should help organization. SSTs are slightly above normal, though TCHP remains relatively low--as expected in mid June--in the GOM. This should limit the intensification potential of this low. 

Track remains the key challenge IMO. The Euro is running now, but past model suites have pitted the Euro and Ukie against the Canadian:yikes:, Para, and increasingly the regular GFS. The Euro and Ukie thus far have had a weak low that moves west to WNW across the central GOM toward Mexico, while the opposing camp bring a low toward the northern Gulf coast.

Given what we know about the Canadian:yikes:, I'm not fond of the Para handling tropical lows like its cousin. That said, I understand the reasoning behind the model forecast. The ridge in the SW is a bit weaker/less expansive, which gives this a window to head north and get caught up in the front/trough rolling through the east. IF that possibility were real, it'd be worth watching if we could get some moisture up here. Maybe a faster progression of the system to tug it north a bit?

All that said, money's on the Euro/Ukie until further notice. That's a baaaaad ridge in the SW. 

 

Would love to see some tropical moisture roll into the region but to be honest I haven't been impressed with this setup for awhile now.

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25 minutes ago, losetoa6 said:

Just looking from an impact senerio for a our region ..many ensemble members bring at the very least some residual moisture from the gulf low up here and some look to bring decent remnants. 

Just looking at the op Euro at 500 it would bring remnants verbatim to the mid Atlantic looking at this ..shooting around that sw atlantic high . Coming from the due south would be better of course but hey..

170618134946.gif

At this point the timing of the trough and the tropical system are off but definitely plenty of time for adjustments. Slow down that trough by roughly 24 hours or quicker development and movement northward of the system and I think we are in on the gravy train. Otherwise I think we see very little moisture, if any, make it into our region, especially the northern portions, as most of it gets shunted through the south east. Of course this is all in regards to the GFS because the Euro wants no part of it. Here's hoping. Really want the rain for the yard and the garden.

 

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2 hours ago, WxWatcher007 said:

Not sure it's worth talking about much, but there were some interesting changes with the 12z suite so far. GFS and Para continue pulling west. GFS has 93L basically stalling near the LA coast before it gets picked up and passes to our south on Saturday. That'd bring some moisture. Para quasi-stalls too before an LA landfall and trip up and to our west on Friday. 

Meanwhile, the Canadian:yikes: abandons ship on a FL landfall and brings 93L into Texas and the Ukie--which was once the furthest south of the guidance--now brings 93L into the TX/LA area probably early Thursday. 

Waitin' on the Euro...and hopefully the HH...

Euro says...

Image result for hasta la vista baby

 

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1 hour ago, WxWatcher007 said:

Weird run. Everything seemed to coalesce and it took the slp south. Not much to do until we have a well defined center.

Frustrating.

 

 

Think the difference in outcomes we are seeing are in relation to the different interactions between the system and the trough sliding through the east at day 2. GFS shows the trough influencing the system somewhat, pulling it just far enough north to get into the southwesterly flow. Euro on the other hand shows little to no interaction leaving the system farther south within the easterly flow. Considering the setups leading into day two are very similar on both models leads me to believe we are talking a somewhat fine line between both solutions. So at this point I think both solutions are very much on the table and we may not know what we have up until game time.

Edit: Forgot to mention the fact that the initial development farther south on the euro vs the GFS  probably is playing a key part in the lack of interaction between the trough and the system on the Euro.

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33 minutes ago, WxWatcher007 said:

Advisories forthcoming on the low east of the Windward Islands at 5pm. Not classified yet...these will be Potential Tropical Cyclone Advisories. 

BULLETIN
Potential Tropical Cyclone Two Advisory Number   1
NWS National Hurricane Center Miami FL       AL022017
500 PM AST Sun Jun 18 2017

...TROPICAL STORM WARNING ISSUED FOR PORTIONS OF THE WINDWARD
ISLANDS...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...7.5N 50.4W
ABOUT 815 MI...1310 KM ESE OF THE WINDWARD ISLANDS
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 23 MPH...37 KM/H
MINIMUM CENTRAL PRESSURE...1008 MB...29.77 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

The government of Barbados has issued a Tropical Storm Warning for
Barbados, St. Vincent, and the Grenadines.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* Barbados
* St. Vincent and the Grenadines
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47 minutes ago, WxWatcher007 said:

It's lost in our current severe day, but the odds seemed to have improved quite a bit for us getting remnant moisture. How much, idk, but a rainy tropical day in June works for me. 

I see LWX already has talked about it for Sunday into next week in their AFD

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3 minutes ago, WxWatcher007 said:

Now that's severe season's over, back to the tropics. 

We have Tropical Storm Bret west of the windward islands. Advisories will begin at 5pm for PTC 3 in the GOM.

Yep. Thinking it's a weekend deal though. We need to be squarely in the moisture plume lol. Just in time for the get together this Saturday.

Hmmm...could see Cindy within 24 hours.

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For PTC3 in the GOM

WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

A Tropical Storm Warning is in effect from Intracoastal City,
Louisiana, to the Mouth of the Pearl River.

A Tropical Storm Watch is in effect from west of Intracoastal City
to High Island, Texas.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* Intracoastal City to the Mouth of the Pearl River

A Tropical Storm Watch is in effect for...
* West of Intracoastal City to High Island

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area, in this case within the
next 24 to 36 hours.

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.

Interests elsewhere along the U.S. Gulf Coast from the central Texas
coast to the western Florida Panhandle should monitor the progress
of this system.
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