Wednesday, October 13, 2010

Ready for the first shot of some Cold Air?

Models and Ensembles starting to show some true signs of the first Cold outbreak across the East. This looks to take shape the week leading up to Halloween. Temperatures during this period across the Northern Plains, Ohio Valley and into the Northeast could be up to 20 degrees below normal. The pattern luckily won't stick around at least at that intensity. However will likely produce the first hard freezes and maybe first snow flakes. Lots of questions on timing, strength of trough and what kind moisture will be around. With that being said I wouldn't be surprised if Chicago, Indy, Cincy, Pittsburgh, Buffalo all see there first snowflakes by Halloween Weekend.

Ex. Chicago
Trace or More
Average Date: October 30th
Earliest: September 25, 1942
Average Date: November 16th
Earliest: October 18, 1989 (0.7 inches) October 18, 1972 (0.2 inches)
 Latest: December 16, 1965 (0.3 inches)

One Inch or More
Average Date: December 2nd
Earliest: October 19th, 1989 (3.8 inches) Latest: January 17, 1899 (1.0 inch)

Ex. Indianapolis
Average Date of First Measurable Snowfall: November 19
Average Date of Last Measurable Snowfall: March 30
Earliest Date of First Measurable Snowfall: October 18, 1989
Latest Date of Last Measurable Snowfall: May 8, 1923

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