A norlun trough set up will bring plowable snowfall to the region once again Wednesday Night and into Thursday. A norlun trough is an instability trough created by easterly onshore flow. This particularly favors elevational snowfall, with widespread 2 to 4 inches but isolated windward locations receiving up to a foot of snow. The GFS and NAM are starting to come in line with stronger downstream ridging along with coastal development transporting sufficient moisture on easterly winds to the region Wednesday Night into Thursday. Precipitation type will be an issue for much of the region because of the flow off of the warm ocean waters, however Keene may be far enough inland to escape any mixing precipitation, and to stay snow. Generally expecting a water content of .3" to .7" with higher elevations of Keene receiving .4" to .8".
Snowfall forecast for 12z Wednesday through 00z Thursday: 3" to 6"
This may need some upward adjustment, but remaining conservative for now. Again, the amount of emphasis on banding and isolated amounts make for a tricky snowfall forecast. First and final forecast map will be issued tomorrow.
|posted by Sam Lillo @ 12/18/2007 07:06:00 PM
