Pressure Charts Vs. Wind Forecasts

[Pennine Ten Foot Drifts]

I had always been fairly clear in my mind about the relationship between charts and wind, (basically, the tighter the isobars the stronger the wind, and wind direction loosely linked to the directional flow of those isobars). So how does a Met Office forecast for Yorkshire for tomorrow of strong SW winds:

fit with a chart for the same period of this?:

As far as I can see a chart like that would result in light W - NW winds ?

Edited January 8, 2012 by Pennine Ten Foot Drifts

[knocker]

I had always been fairly clear in my mind about the relationship between charts and wind, (basically, the tighter the isobars the stronger the wind, and wind direction loosely linked to the directional flow of those isobars). So how does a Met Office forecast for Yorkshire for tomorrow of strong SW winds:

I think that maybe a bit simplistic but no doubt someone will hopefully correct me.

Curved flow with friction comes into play.

• Friction slows motion (always opposite to the motion).
  

• Friction is important only in the lowest 1 kilometer of the atmosphere.
  
• The wind direction changes such that the flow is across the isobars toward lower pressure.
  Hence, near the surface, air converges into the center of a low and diverges away from the center of a high. Because this convergence or divergence is on the surface and air cannot go down through the ground, we have vertical motion above the surface.
  

I would have thought from the chart easing westerlies looks okay. But what do I know?

[Terminal Moraine]

I think the Met' Office are basing their forecast on the fax chart which shows a similar synoptic situation to the one posted above but with the isobars closer together and the high pressure exerting less of an influence.

There's also a cold front moving south on Monday which isn't immediately evident on the GFS chart and which is likely to increase the wind speed.

[knocker]

I had a glance at those charts as well TM if these are the ones to which you refer.

[Terminal Moraine]

Yes, they're the ones W.S. Certainly a more enhanced north westerly flow there than on the GFS charts.

[Pennine Ten Foot Drifts]

Thanks for the replies, I guessed it might well be a bit more complicated ! Mind you I notice the Met Office has gone from 'strong' to 'fresh' SW winds, so perhaps I wasn't all wrong

[Pennine Ten Foot Drifts]

Well, far be it from me to keep banging on about something like a broken record, but today's wind map: