Question Box:

[angelwing]

Maybe this should be a sticky? The info from here is very helpful and I'm getting questions answered that I would have asked!

[wjs3]

I am going to try on the warm vs core-cold core question...

For all the professional mets and well-educated amateurs that read this, I know I am skimming over a lot.

A2K, you've asked a great question that really requires delving into some more advanced stuff to fully "get". But I'll try.

Cold-Core lows are essentially baroclinically driven. They get their fuel for development from zones of temperatre contrast (baroclinic zones) and their "spark" from mid level troughs and or lows (at 500 MB). They are characterized by cold air aloft (troughs/lows aloft are signs of colder air). Cold core/extratropical lows are characterized by being near a baroclinic zone. That means that you'll see cold/warm fronts around them.

Tropical Cyclones (Warm core) develop and get their energy totally differently. In a classic tropical cyclone, there's no baroclinic zone (temperature contrasts are small in the tropics). In warm core (tropical) development, a disturbance (like a tropical wave) starts things off. If conditions are right, that disurbance taps into the all the water vapor avaiable over the oceans, and big-time storms can fire. These storms can work together to lower surface pressures and create HIGH pressure (not low!) above the "surface" system that is a hurricane (this takes advantage of latent heat--a whole other topic). High pressure means sinking air...and, in the eye of a hurricane, or center of a developing tropical cyclone, you'll see signs of this sinking as air will actually warm--air warms as it sinks. (by the way, no baroclinic zone means no fronts, etc in a mature tropical cyclone)

In fact, in a mature, strong hurricane, one sign of strength is the temperature difference between air outside the eye and air inside the eye. It's actually reported in the Vortex Data Message from Recon. A sharp temperature contrast means that the processes I describe above are well under way.

I got kind of technical (yet glossed over a bunch of stuff) here. Hope this helps.

And hope anyone who catches a technical error in the above will correct me.

Best--

WJS3

[mvtrucking]

TUTT and what bearing it has on tropical waves? I have seen it used recently and was unable to find it in the NWS glossary of terms or NHC acronyms.

jusforsean wrote:

TUTT cells are basically cut off upper lows that just meander around in the tropics. A TUTT to the north or east of a tropical system can help out by enhancing outflow. A TUTT to close to a system will shear it. Sometimes TUTT's can develop into a tropical system themselves.

TUTT stands for Tropical Upper-Tropospheric Trough.[/quote]
_______________________________________________

Thank you for defining that.. Also to A2K, Wxmann91, Senorpeper

[Audrey2Katrina]

Maybe this should be a sticky? The info from here is very helpful and I'm getting questions answered that I would have asked!

I know a lot of folks who read through these things and feel they would seem silly asking these questions; but I feel that's what the board is here for... to add to our base of meteorological knowledge. Never be shy... just ask away... I will, not the least bit shy about it, and I teach science.

A2K

[Audrey2Katrina]

Thanks Wis3, I had a "kind'a sort'a" concept of the two, and your explanation seems to have reinforced those concepts with still more appreciated insights.

A2K

[stpeteweathergal]

I've seen "MJO" (I think that's what they call it) in discussions? What does that stand for and it's impact to storms?

[wxmann_91]

I've seen "MJO" (I think that's what they call it) in discussions? What does that stand for and it's impact to storms?

The Madden-Julian Oscillation. Different phases and amplitudes of the MJO affect the convection in the tropics. It's pretty tough to understand, but I googled some links

http://www-das.uwyo.edu/~geerts/cwx/not ... 2/mjo.html

http://www.apsru.gov.au/mjo/index.asp

http://www.icess.ucsb.edu/asr/mjo_forecasts.htm

http://www.cpc.noaa.gov/products/precip ... index.html

This one has acronyms for other indexes and oscillations - http://ggweather.com/enso/mjo.htm

[stpeteweathergal]

Yikes!! Looks like I asked for a doozie. I have some reading to do. Thank you very much wxmann_91.

[wxmann_91]

No problem. This is a great thread idea

[wjs3]

Glad to help.

Great question re: MJO too.

[wxmann_91]

I've been responding to so many questions, I really should ask some of my own...

1) What constitutes lower, mid, and upper levels of the atmosphere (in mb)?

2) I don't really get what are lapse rates. I know it must have something to do with instability.

[HurricaneHunter914]

What exactly is the cause of shear and what causes it to increase or decrease?

[wxmann_91]

What exactly is the cause of shear and what causes it to increase or decrease?

Shear is caused by anticyclones, cyclones, wind cells, TUTT's, troughs, and there are a lot more. Nearly all weather systems on earth create shear in one way or another, otherwise, cyclones and anticyclones couldn't fulfill their purpose of moving air across the globe (which basically what shear is). The movement of these systems causes shear in localized areas to increase or decrease. So, pretty much, when you want to forecast shear (during the summer - winter the westerlies are dominant so there's not much forecasting), look at the systems that cause the shear. I would think that the net shear across the globe would remain fairly constant throughout the year. Anyway that's my take on it.

EDIT: Wikipedia has a good article, localized wind shear can be induced orographically. http://en.wikipedia.org/wiki/Wind_shear

[angelwing]

If I remember last year I think someone was talking about a "1028" line? (I think that's the correct number) Could someone explain the significance of that?

[chadtm80]

Maybe this should be a sticky? The info from here is very helpful and I'm getting questions answered that I would have asked!

There is a link to it on our homepage.. Right under the 91L Invest info.. Its a BIG animated Question Box image.. You cant miss it

[angelwing]

Cool! Thanky Chad!!!

[Cyclenall]

If anyone wants to answer a question, mine on the first page has not been answered yet. It's not really a question but something different.

[Audrey2Katrina]

Is that the one asking exactly what different conditions can wind up developing into a TC? I know that beside the things you mentioned they can develop from a TUTT; albeit rarely.

A2K

[wjs3]

If I remember last year I think someone was talking about a "1028" line? (I think that's the correct number) Could someone explain the significance of that?

Angelwing, that sounds like it may have been in reference to an Isobar--a line that marks places of equal pressure. That's pretty high surface pressure (1028 MB) and probably marked part of a surface high/ridge. I'm guessing here, but we normally watch that stuff because forecasting TC track often has to do with finding weaknesses in a ridge...or assessing the shape of a ridge/high. So knowing where particular isobars are located can help us in doing so.

Hope that helps.

WJS3

[wjs3]

I've been responding to so many questions, I really should ask some of my own...

1) What constitutes lower, mid, and upper levels of the atmosphere (in mb)?

2) I don't really get what are lapse rates. I know it must have something to do with instability

1) Let's use CIMSS as a guide for purposes of this...see here:

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

Lower is "about" 600 MB down
Mid is maybe 400-600
Upper is above 400 to the tropopause

I would guess there's a lot of judgement involved in this assessment, but those seem reasonable.

2) Lapse rates are the change in air temperature with altitude. You are right on that "steep" lapse rates--quick cooling of the atmosphere altitude--means instability--a parcel that ascends in such an environment (given certain other conditions) will tend to continue to ascend. Slow lapse rates--where the atmosphere cools only a little (or even warms...an inversion) are indicative of stability--here, a parcel that begins to ascend will either stop ascending, or may even sink.

WJS3