Ex Tropical Depression KAREN: Discussions & Images

[SouthFLTropics]

There is no question about it, she is fighting for her life. It seems like she is attempting to take the path of least resistance and try and avoid the shear to stay alive. The convection is not all that impressive but the circulation is still very evident.

SFT

[chris_fit]

Just the opposite. The northerly motion means relative shear is down. Convection is returning to very near the center. Could hang in there and actually BE a TS by this afternoon.

I was just about to ask about this. My thinking too... By going north it will actually have a greater chance at survival.

[Chacor]

some good news for the Karen fans... the working best track file does have Karen as a hurricane for 12 hours

I noticed that, Derek. NRL, based off ATCF, was carrying Karen at 65 kt for a while (but the TPC adv went with 60 and a note that it probably was a hurricane).

Anyway, any idea why the TPC went from a restrengthening scenario (50 kts) to 30 knots flat out for five days? That seems to be quite big a change in an intensity forecast in just six hours.

[BigA]

Just the opposite. The northerly motion means relative shear is down. Convection is returning to very near the center. Could hang in there and actually BE a TS by this afternoon.

Would moving north move it out of the high shear area more quickly than a WNW/NW course?

[AnnularCane]

Karen looks so tiny all of a sudden.

[Air Force Met]

Karen is moving due north. I cannot understand how one could derive a WNW track out of due north

Because they weren't forecasting a due north motion...so its still moving WNW until they have no choice.

Now...if they were forecasting a turn to the north you can bet your last dime the 11 Am advisory would have stated it was moving north.

Its that whole forecast verification thing.

[Lifesgud2]

Karen is moving due north. I cannot understand how one could derive a WNW track out of due north

Because they weren't forecasting a due north motion...so its still moving WNW until they have no choice.

Now...if they were forecasting a turn to the north you can bet your last dime the 11 Am advisory would have stated it was moving north.

Its that whole forecast verification thing.

I know it is difficult, but what is this thing going to do in the coming days? Is the shear supposed to let up?

[wxman57]

Karen looks so tiny all of a sudden.

That's because it's intensifying as relative shear decreases. Convection isn't 150+ miles from the center now, it's only 20 miles from the center.

[tolakram]

Sudden move to the north and now convection very close to the center, eastern side. This is why I love the tropics!

Now I wonder why, when, and if it will help.

[storms in NC]

You can see in this Vloop that she is tring very hard to wrap Convection around her. As she goes NORTH

http://www.ssd.noaa.gov/goes/flt/t1/loop-vis.html

[tolakram]

Karen is moving due north. I cannot understand how one could derive a WNW track out of due north

Because they weren't forecasting a due north motion...so its still moving WNW until they have no choice.

Now...if they were forecasting a turn to the north you can bet your last dime the 11 Am advisory would have stated it was moving north.

Its that whole forecast verification thing.

I respectfully disagree. It seems to me that there's a fine line between wobble watching and direction changes. I bet they will admit in the next discussion that what they thought was a large wobble turned out to be a direction change. Six of one, half a dozen of the other. Nothing predicted a due north motion so I think they chose the most reasonable route.

[wxman57]

6-hr movement toward 2 deg (North) at 13.5 kts. It moved 81 miles due north the past 6 hours.

[Air Force Met]

I know it is difficult, but what is this thing going to do in the coming days? Is the shear supposed to let up?

Well...it's hard to deny the current trend and that the models didn't see it. As far as the shear goes...I don't think it will let up any time soon...other than the relative fact that it is moving north with the flow. It will be an uphill climb.

[wxman57]

Comparing current motion to NHC 10am track, the center will cross 16N near 49.1W in just under 2 hours. NHC has the center crossing 16N at 51W near 10pm-11pm this evening. That's about 120 miles west of where the center will cross 16N. From its current position, it needs to move at 283 deg. to reach 16N/51W.

[Fego]

There she goes.. up north. 12:30 p.m. The red x is the NHC initial point, and the yellow line is the proyected path... aprox...

[otowntiger]

Karen is moving due north. I cannot understand how one could derive a WNW track out of due north

Because they weren't forecasting a due north motion...so its still moving WNW until they have no choice.

Now...if they were forecasting a turn to the north you can bet your last dime the 11 Am advisory would have stated it was moving north.

Its that whole forecast verification thing.

I respectfully disagree. It seems to me that there's a fine line between wobble watching and direction changes. I bet they will admit in the next discussion that what they thought was a large wobble turned out to be a direction change. Six of one, half a dozen of the other. Nothing predicted a due north motion so I think they chose the most reasonable route.

Isn't it true little weak storms like this don't really wobble. Its a term that should only apply to those tightly wound systems with a clear eye. Those wobble, because the eye within the whole storm sometimes is spinning like a top, and moves around withing the storm. A little weak storm like this just moves one way or the other. It has no tight spin in order for it to wobble. That's just my opinion.

[Air Force Met]

I respectfully disagree. It seems to me that there's a fine line between wobble watching and direction changes. I bet they will admit in the next discussion that what they thought was a large wobble turned out to be a direction change. Six of one, half a dozen of the other. Nothing predicted a due north motion so I think they chose the most reasonable route.

You are free to disagree but it doesn't change the fact that they do this all the time...I've watched them do it for years and its usually predictable. Movement is movement. From the earliest visible images is was obvious it wasn't a wobble. Sheared systems don't wobble in one direction for hours at a time at 12+ knots. That's a movement that is caused by a change in the steering flow.

And it is a certainty that if a northward turn had been forecasted...what they were observing this morning would have been described as "KAREN IS NOW MOVING NORTH NEAR 9 MPH." You can bet on it and that is what I am saying. But...since WNW is the forecast...they hold off until they can't any longer. So I guess the point is don't call it one thing when it is convenient and fits the forecast and another when it doesn't.

What would have been prudent would have been to say "KAREN HAS BEEN MOVING TOWARDS THE NORTH AT 9 MPH OVER THE LAST FEW HOURS BUT A TURN BACK TO THE WNW IS FORECASTED."

And actually the BAMD did predict the turn. It sees the deep layer steering flow would direct a storm northward because of increasing shear. Karen was deeply stacked apparently and responded.

[Blown Away]

Definite convection building to the E and it looks much better than earlier this morning. I'm stunned how far off track Karen is from the NHC track, I can picture those guys over at the NHC glued to a monitor watching Karen go N and scratching their heads.

[tolakram]

Thanks for taking the time to explain AFM.

[DelrayMorris]

some good news for the Karen fans... the working best track file does have Karen as a hurricane for 12 hours

What does that mean, Derek? (the working best track file)

I don't see how Karen can be a hurricane in 12 hours. She seems to be impressively holding on to BARELY TS status right now. Does the 'working best track file" actually have any accuracy?

No, that's not it...

"the working best track file does have Karen as a hurricane for 12 hours"

That means, at one point, for 12 hours, it was a hurricane.

Thanks, everyone. I learned something new today. I was heartily confused by that for a bit.