please help me understand the senario setup

[boca]

I can't understand why if the two systems north of Frances are just sitting there pull Frances more north than what the GFS is calling for? The flow east of 98L is southwest and wouldn't that pull Frances more poleward even though the high pressure is supposeably building in to turn Frances West. It's just too confusing.

[B-Bear]

I can't understand why if the two systems north of Frances are just sitting there pull Frances more north than what the GFS is calling for? The flow east of 98L is southwest and wouldn't that pull Frances more poleward even though the high pressure is supposeably building in to turn Frances West. It's just too confusing.

As I understand it, the systems ahead of Frances are forecast to be long gone by the time she gets there, and the ridge will quickly fill in behind them as they leave. So they are not predicted to have any affect on steering her. The ridge will prevent her from steering north.

[boca]

thankyou ,but Frances is still moving,but the other two systems aren't so wouldn't that play in as a factor.

[lilbump3000]

Even though the others ones are not moving, once the high starts to build well that is what i think suppose to push gaston into the SC coast and for that other system, lord knows what its going to do with it.

[B-Bear]

thankyou ,but Frances is still moving,but the other two systems aren't so wouldn't that play in as a factor.

Frances has a slow forward motion--about 11 mph, last I heard. Those other systems are not currently moving, but they are forecast to start moving shortly. They are therefore predicted to be gone by the time she gets here. Of course, if they don't start moving as forecast, and if Frances' forward motion increased (seems unlikely at this point), then, yes, they could have an affect on her steering. But that seems rather unlikely at this point.

[frankthetank]

thats my thinking too...those systems are stationary??? or are they?

and there seems to be a lot of dry air around these 2...check out the WV loop

http://www.rap.ucar.edu/weather/satelli ... g&itype=wv

[B-Bear]

That is actually a very nice image to post for this conversation, because it will enable the original poster to see that ridge digging into the middle of the U.S. and moving east. It looks like it is quite strong to me, as predicted. As that ridge continues to move east, those other systems should start moving more and be out of Frances' way before she gets here.

[Guest]

I would think & dont quote me on this for as much as I love the tropics certain things still bewilder me.

Eventually TD #7/Gaston begins to move NW, N makes landfall gets caught up in the front & gets shunted NE rather quickly & is out of the picture by Tue/Wed @ the same time the developing system gets under the influence of the building ridge & begins moving W & then NW & eventually N.The High continues to build Wward behind the departing systems & keep Frances on general W/WNW track.

Just my thoughts I am certainly not an expert in steering currents...NHC has noted in there TWOs that a system south of Bermuda may develop so they know its there & yet their track stays consistent.