Tuesday, October 12, 2010

Another Possible Fall Nor'easter for Thursday-Friday of this week?

Once again another interesting weather scenario appears to be in store for Upstate New York (and probably all of the Northeast U.S. for that matter) for Thursday through Friday (14th-15th October) of this week. Well, at least from this forecaster's perspective it is interesting.

After a cool start to the weather for the first almost two weeks of this month the pattern across the Lower 48 appears to be undergoing a change: For much of this month (even going back to the end of September) the jetstream has been rather active and strong as well as having many "dips" in its flow as it work blows across the Northern Hemisphere. These "dips", also known as troughs (which are areas of lower pressure aloft), have resulted in low pressure systems at the surface of the earth to move across the Northeast U.S. bringing much needed rainfall. With the passing of these lows cooler than normal air has followed with many areas, especially across interior Eastern New York State experiencing temperatures averaging below normal along with nighttime frosts and or freezes for many locales.

By the end of this upcoming weekend and into the start of next week it looks like the jetstream will be having less in the way of significant "dips" in it. It will likely be blow in a fairly west to east flow pattern (called a zonal flow). This sort of a jetstream tends to result in weak and fast moving weather systems. Temperatures tend to be closer to normal if not somewhat above normal, especially during the daytime hours.

As often happens when there is a pattern change or the jetstream transitions from one state (like the current one with the "dips")  to the forecast one ('zonal" flow for next week), the atmosphere tends to "react" to this change with a storm development.

Latest data is indicating that this storm development will likely be along the East Coast of the U.S., however the question is where? Anywhere from the NJ coast to the Virginia Capes is possible.

The next question is once the storm does develop what track will it take? Here too data is indicating mixed signals: Tracks vary with the data tracking the storm either across Western New England to Northern Maine or moving it east and passing across Eastern Massachusetts to the Gulf of Maine and Nova Scotia.

Newer data will be coming in throughout the day and I'll post some more tonight, work permitting.

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