fact789 wrote:i think the fat ladys humming and ready to explode (in either way)
Rolling on the floor

Moderator: S2k Moderators
AJC3 wrote:If the shear is 25 knots, then it's 25 knots. The shear is the magnitude of a vector difference that is caluclated relative to a base level, and typically these charts uses H85 wind. If storm motion is roughly the same as the H85 wind vector (sans the storm circ itself), then the shear charts are fairly accurate. If the shear was calculated relative to ground level, then what you would have would be...ahem...250MB windspeed.![]()
AJC3 wrote:
Whoa! Hang on a sec, here. This isn't correct!
If the shear is 25 knots, then it's 25 knots. The shear is the magnitude of a vector difference that is caluclated relative to a base level, and typically these charts uses H85 wind. If storm is moving roughly with the H85 wind, then the shear charts are fairly accurate. If the shear was calculated relative to ground level, then what you would have would be...ahem...250MB windspeed.![]()
Now if someone was to look at an H25 isotach chart and say, "hey there's 35 knots of NE wind, that will start to rip away the convection, then you could pose your argument about storm motion.
southerngale wrote:Yep, she's definitely looking better with all this running on and off stage.
Air Force Met wrote:AJC3 wrote:
Whoa! Hang on a sec, here. This isn't correct!
If the shear is 25 knots, then it's 25 knots. The shear is the magnitude of a vector difference that is caluclated relative to a base level, and typically these charts uses H85 wind. If storm is moving roughly with the H85 wind, then the shear charts are fairly accurate. If the shear was calculated relative to ground level, then what you would have would be...ahem...250MB windspeed.![]()
Now if someone was to look at an H25 isotach chart and say, "hey there's 35 knots of NE wind, that will start to rip away the convection, then you could pose your argument about storm motion.
Hold on...I wasn't speaking of shear in those terms...I was speaking in terms of upper level winds. In other words...if the 300mb winds are 25 knots...etc. I am calling 25 knots of wind over the top of a tropical depression shear. It's less shearing if it is blowing in the same direction as the storm is moving..than if it is moving in the opposite direction. Hence the 250-850 shear maps.
I think the individual knew what I was saying....or I hope. Didn't mean to confuse. It's hard to break habits. When we are in the office...when we talk about shear...there...of course...certain things that are understood....and what you pointed out is one of them.
curtadams wrote:AJC3 wrote:If the shear is 25 knots, then it's 25 knots. The shear is the magnitude of a vector difference that is caluclated relative to a base level, and typically these charts uses H85 wind. If storm motion is roughly the same as the H85 wind vector (sans the storm circ itself), then the shear charts are fairly accurate. If the shear was calculated relative to ground level, then what you would have would be...ahem...250MB windspeed.![]()
All true. But what is the shear over Chris? CIMMS says it's in the teens, and my eyes agree. The convection SE of the LLC looks like it's under pretty moderate shear.
AJC3 wrote:
Ah. Gotcha. Just wanted people to remember that those shear values are actually computed, subtracting out the low level wind. I checked the CIMSS site again, and it's H70-H925 used as a basline. Sometimes upper level winds and upper level wind shear are used interchangably on here.
Air Force Met wrote:AJC3 wrote:
Ah. Gotcha. Just wanted people to remember that those shear values are actually computed, subtracting out the low level wind. I checked the CIMSS site again, and it's H70-H925 used as a basline. Sometimes upper level winds and upper level wind shear are used interchangably on here.
Yeah...but I don't look at those charts all the time...especially in real time. I try to look at the raw values when I am just examining a satellite pic.
Brent wrote:I hope the fat lady knows how to perform CPR...
Users browsing this forum: Ivanhater, StormWeather, Ulf and 49 guests