Tuesday, August 27, 2013

Weather It Is (The Winds Of Fall (Or, Is That War?))

Good evening:

The winds are about, and my wife was heard to comment that these are the winds of fall.  We hope that  fall transitions into winter without incident, but the winds of war are also blowing, and of course we're being threatened.

There was some very interesting research published by Dr. Amir Givati and Professor Daniel Rosenfeld (of the Israel Hydrological Service and The Hebrew University of Jerusalem, respectively).  They found that December through February changes in pressure related to the "Artic Oscillation" (AO) correlate very well with precipitation changes in the Middle East. Quite interestingly, positive manifestations of the AO correspond to decreases in rainfall over the northern part of Israel (and even stronger decreases to our north), but there is an increase in precipitation over the central areas).  The negative manifestations correspond to comparatively more rain over the northern areas. As Greenhouse gases have grown during the last few decades, the AO has been more positive than negative, and there has been  a downward trend in precipitation amounts over our north, and more rain in central/southern Israel.   This also leads to a more northerly flow -- meaning that winters can actually be cooler in our area as large parts of the rest of the world warm up (with higher Greenhouse gas concentrations).

So, how do we look seasonal prediction wise (from the Climate Forecast System model)?  We look average in temperature and precipitation for this upcoming winter. Perhaps, then, it is not ironic that the next two weeks look to be more of the same with little change.

Shana Tova,

Barry Lynn