Sunday, August 28, 2011

Irene Impacts on New York's Catskill Mountains

There are some remarkable photos and videos of flooding in the Catskills on  Keep in mind this is not storm surge.  This is runoff from torrential rains.  A sample is below, taken by David France and appropriated from YouTube.

Radar-based precipitation estimates show widespread totals of 3+ inches across the region, with areas >6" or even >8" in areas of Greene County, which lies west of Hudson (click on images to enlarge).  This is the region where many of the flood photos and videos are from.

Source: Weather Underground.  Accumulations since 27 Aug.
I'm not very familiar with the KENX radar from Albany and am not sure how trustworthy those estimates are.  On the other hand, the radar reflectivity images overnight look legit, with realistic radar reflectivity maxima, for example, at 1256 UTC in the areas of great accumulation.

Source: NCAR/RAL
At this time, strong northerly to northeasterly flow was impinging on the Catskills, as suggested in the MesoWest analysis below.

As seen in the terrain image below, such flow is oriented normal to the two NW-SE oriented ridges in the Catskills.  The radar-derived precipitation maxima lie over these ridges.

Thus, it appears we may be looking at a case of local orographic precipitation enhancement over the NW-SE oriented ridges of the Catskills.

No comments:

Post a Comment