#9 Postby Aslkahuna » Thu Jul 28, 2005 4:41 pm
Well, there is an idea running around that the heavy snows in the AZ mountains and the Intermountain West has something to do with the late start to the monsoon since it took some time for the interior to warm up enough to begin the process of establishing the monsoon. However, this does NOT explain the recent late starts that followed dry winters with little snow cover. I tend to think that it's more closely tied to atmospheric pattern changes associated with the development of ENSO warm phase (El Niño) events. It appears that during Summers that both preceed and follow the winter onset of a Warm Phase event we have late starts though rainfall is not closely dependent upon when the monsoon starts. The rainfall as of late seems to have been somewhat tied to the increase in ATL Tropical activity and, most importantly, the corresponding decrease in EPAC activity along with a general lack of systems traversing the GOM into Southern TX and NE MX. In addition the Drought, which contrary to Popular Opinion is still very much with us despite a single wet winter, is also affecting rainfall by virtue of drying out the low levels and preventing
normal rainfalls from storms. There has also been a pattern change whereby areas that usually get the most monsoon rain has been bypassed while western and NW AZ is getting more.
Steve
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