Seasonal Indicators (Beyond Day 16): Instability / SST's / MSLP / Steering / Sal

[USTropics]

what causes the atlantic hurricane season not really Activity anymore but why ???? I know july ,,



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There are multiple reasons why July does not see activity (14% of the Atlantic activity occurs in June/July). For starters, the Atlantic is typically still in a transitioning phase. We usually see a very strong Bermuda High, suppressing activity in the MDR. This also enhances the flow of SAL, as well as contributes to drier air in the MDR region. Cold fronts, a source of tropical genesis, do not propagate into the tropics at high frequencies.

As you can see on the graphic that Tolakram posted earlier (and the one below), a large portion of activity is based westward, off the East Coast and in the GOM during July.




As we transition to August, we generally see the ITCZ lift north and an increase in vigorous AEWs. This combination allows for tropical waves to either gradually form as they cross the MDR or at least provides a suitable environment until they reach the Caribbean.

[xcool22]

Okay thanks

[CaliforniaResident]

Remember that 2004 didn't even get its first named storm until August and we all know what happened once things got going!

[TheStormExpert]

 https://twitter.com/tropicaltidbits/status/756873206292684800




 https://twitter.com/tropicaltidbits/status/756873738042372096

[ninel conde]

WXrisk gives me some back-up as i have been saying conditions will just get worse as aug/sept gets here.

Wxrisk.com added 3 new photos.
42 mins ·

GREAT NEWS AUGUST 2016 LOOK A LOT COOLER

All Model data shows mean trough returning to the Eastern US and probably the East coast in 1st week of AUG and staying there for all or most of the month.... and it turns wetter !! Euro weeklies keeps mean trough over eastern us thru aug 15-20


That will definitely be a damper to those saying the gom and east coast will be threatened or where storms will form. Should create alot of shear in the west atlantic and GOM. looks like a 1976 or 1986 looks likely though possibly without a charlie or belle. I have to assume the trof will just get stronger in sept. except for an exteme fluke i think a fla cane landfall of major landfall anywhere in US seems rather unlikely.

[psyclone]

The CPC 6-10 and 8-14 day outlooks both show above normal temps in the east with the latter warmer overall than the former. That's not what I'd expect to see if things were getting troughy.

[ninel conde]

The CPC 6-10 and 8-14 day outlooks both show above normal temps in the east with the latter warmer overall than the former. That's not what I'd expect to see if things were getting troughy.

I guess we will see. Im betting on pattern persistence which has kept us major free for 10 years now and cane free in FLA for 10 years.

[Alyono]

of course there is going to be an eastern trough. Long range EC was showing this. It also was showing a lingering surface trough in the Gulf

THAT IS WHERE WE NEED TO LOOK FOR DEVELOPMENT

[MGC]

Well, SST are cooking in the GOM. 93 in the central gulf, 90 just off the coast from Mississippi. Hope all activity avoids the gulf this year.....MGC

[ninel conde]

Well, SST are cooking in the GOM. 93 in the central gulf, 90 just off the coast from Mississippi. Hope all activity avoids the gulf this year.....MGC

has the rain been well above normal due to the high sst's?

[TheStormExpert]

Well, SST are cooking in the GOM. 93 in the central gulf, 90 just off the coast from Mississippi. Hope all activity avoids the gulf this year.....MGC

has the rain been well above normal due to the high sst's?

Warm SST's I believe correlates to little or no rain.

[ninel conde]

Well, SST are cooking in the GOM. 93 in the central gulf, 90 just off the coast from Mississippi. Hope all activity avoids the gulf this year.....MGC

has the rain been well above normal due to the high sst's?

Warm SST's I believe correlates to little or no rain.

You could be right. perhaps its keeping land areas dry.

[ninel conde]

LC, a true gentleman, provides some news for atlantic cane followers.


"There are now six fully developed impulses along the ITCZ straddling equatorial Africa. With the heat ridge now firmly ensconced over the Mediterranean Sea, the constant output of hot/dry/dusty Saharan air should decline markedly. With a less-impressive SAL to deal with, impulses exiting the vicinity of Cape Verde should have a better chance of organizing into tropical cyclones. And with that, perhaps threaten populated locations on the west rim of the Atlantic Basin."

[Hammy]

has the rain been well above normal due to the high sst's?

Warm SST's I believe correlates to little or no rain.

You could be right. perhaps its keeping land areas dry.

There's definitely a correlation, but given how dry it's been, I wonder if the same high pressure that's causing it to be dry is causing the water temps to further warm by removing much of the cloud cover.

[Ntxw]

Warm SST's I believe correlates to little or no rain.

You could be right. perhaps its keeping land areas dry.

There's definitely a correlation, but given how dry it's been, I wonder if the same high pressure that's causing it to be dry is causing the water temps to further warm by removing much of the cloud cover.

In the subtropics higher pressures, warmer conditions is a feedback loop to higher SST anoms. The lack of convection to turn the ocean and bring up deeper, cooler water just leaves it undisturbed to warm near the surface which promotes more high pressure and more warm temps. In the deep tropics the phenomenon is opposite, warmer waters promotes thunderstorms and convection.

[ninel conde]

Warm SST's I believe correlates to little or no rain.

You could be right. perhaps its keeping land areas dry.

There's definitely a correlation, but given how dry it's been, I wonder if the same high pressure that's causing it to be dry is causing the water temps to further warm by removing much of the cloud cover.

I wonder if a lack of runoff is also causing sst's to warm

[Alyono]

for all the howling about a quiet season, the 3 named storms have struck the USA already

well above normal

[gatorcane]

I agree with Wxman57's post from a bit earlier in this thread. Things look pretty "normal" for this time of year across the Atlantic looking at things like SAL, shear, instability, etc...the EPAC will eventually quiet down and the Atlantic should start to become more active. During a normal season, you start to see the ramp up around mid-August so for those reasons, that is why I have been thinking second or third week in August for our next named system of tropical origin. I say tropical origin because it is always possible for something to spin up sooner from something liked a stalled front or trough.

[hcane27]

I am not sure where the idea of warm sea surface temps in the Gulf equates to less rain came from , but where I live , near Mobile/Pensacola , we are above normal rain and runoff.

[blp]

You can see the transition happening now with the upward motion of the EPAC diminishing and the E. Atlantic/W. Africa taking over. I expect it to continue to move off the coast into the MDR right in time for the heart of the season.

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