| berrywr |
| (Weather Analyst) |
| Wed Sep 24 2008 05:37 AM |
|
Re: San Juan Area Forecast Discussion afternoon version
|
Raymond's analysis is correct as long as this system remains "shallow". It's 24/0534Z and I just got home from work so I'm just now looking at the data for this evening. It's a broad circulation on satellite but not as organized as it was 24 hours ago. I'll post as soon as I look at all the new data from the 00Z.
Edited to include 24/00Z analysis:
24/00Z – 850mb analysis shows a closed high over NY state with a SW axis extending into TX this evening. Old frontal boundaries with lows are off the Eastern US coast extending SSW into the FL straits. 700mb analysis shows position of high over E Michigan and upper lows 300 miles east of Charleston, SC and over central Cuba. 500mb analysis shows closed upper low just south of Cape Hatteras and 589 decameter high over Indiana with an axis extending to a 590 decamter high the TX/LA border with slight height falls south of the upper low suggesting slight deepening. At 300mb upper low is either barely closed or open waved over E NC and difluence taking shape over the Atlantic Ocean near 25N 78W. 30 and 40 decamter height falls are noted over S FL. 200mb analysis this evening continues to show a deep longwave trough extending southward right along the eastern US to just off the FL coast and southward into the Carribbean. Winds are totally hostile above 25N latitude in the GOM and Atlantic Ocean off the coast of FL becoming much lighter east of 75W longitude and north-south axis of shortwave ridge at 68W. An approach to the SE US and GOM is impossible at this time. Water Vapor loop this evening shows E US longwave trough continuing to amply southward with strong subsidence and dry air well into FL which are reflected by height falls on upper air charts this evening. At this time, cyclogenesis is taken shape off the NC coast with with northerly winds aloft over the Caribbean extending from upper high 200 miles south of Brownsville, TX right along the MX coast. Closed upper low spinning about 600 miles ENE of system appears to be slowly moving NNW in last couple of frames. As for the system itself; there is no westward component to movement whatsoever and in fact it does have the organization it had 24 hours ago. Looking at model data from NCEP – Developing low pressure center along front as discussed in satellite analysis is taking shape and with diving trough into FL, will support low pressure system moving a bit unorthodox for a few days before moving up the coast as an extratropical cyclone. Gurus over at HPC believe system won’t be over water or be in the area long enough to develop subtropical or tropical characteristics. The fly in the ointment is what is likely to become Kyle. Upper air is forecast to become pretty straightforward with a trough along the east coast and a ridge over the Atlantic. It can’t be ruled out that the systems won’t merge down the road but and I’m not about going to speculate when and where at Day 5, but there is no threat to the SE US in this forecast cycle. Either Kyle stays up under that ridge or Kyle won’t survive and there is little room for it to operate at this time.
The upper air package is available at http://weather.noaa.gov/fax/nwsfax.html.
Microsoft Office Picture Manager or Windows Image Viewer will open these charts.