The 2009 Southwest US Monsoon

There are interest afoot trying to change the theme of “The Monsoon”, to the Summer Thunderstorm Season.  I’m not sure if the act has been accomplished yet, or if it will be.

Sunday May Showers in the Desert; Not Normal.



They have been saying that there is a 40% chance of an early monsoon season, perhaps weeks early.  Things like La Niña, which seem to add to this seasons precipitation, and the negative things that detract, are favoring the positive precipitation scenario.

It seems only fair, since these same conditions seem to detract from our winter rains.  El Niño often helps the winter rains and harms the summer ones.  At least that seems very consistent to the last many years of these tropical water phenomenon as they effect the Desert Southwest.

Today. Still May and not the “early” monsoon start date of mid June, today there were conditions somewhat like the monsoon.  This week is said to have a few more rain chances.  The question is; could our start be this early?  Often stars are sporadic.  Usually the monsoon start is determined by dewpoint and elevation.  Tucson’s is a 54 dewpoint for 3 consecutive days.  Phoenix is usually later with a 55 dewpoint.  But last year they perhaps began a shift to the Summer Thunderstorm Season, by declaring the Monsoon Season now starts on June 15, wet or not.

Who said we just talk about the weather but do nothing about it?

I will be meeting with real meteorologist this week.  I will be interested in seeing if I can coordinate with some other local weather spotters  when severe weather is occurring, such as last seasons funnel cloud.  If I can triangulate those of us viewing, we may be better able to identify the location of a severe event.  We live here in a non Doppler covered zone, so eyes on the issue in real time may make a warning difference and add up to better info as we call severe events in.  I’m going to check it out anyway.


To my experience; these summer tornado, and or funnel clouds, have occurred on “Gulf Surges” from the Gulf of California,  which are somewhat unpredictable; happening in Mexico often from the collapse of a mesoscale feature, sending surges of humid air into our present monsoon conditions. And the other enhanced monsoon creature causing  uplift, retrograde low’s/easterly waves, tropical disturbances that might have crossed the Gulf of Mexico into the US-Mexico, or otherwise came up from Mexico.  Last years funnel also seemed to have followed an upper low that may still have been sending upper level cool air aloft from the northwest, greatly energizing cumulus buildups.

We seem unlikely to receive tornado watches, but do get the warning on rare occasion.  I’ve managed to be living in a few of those in Tucson.  Usually these have occurred earlier in the Monsoon Season, but I do not know they cannot occur in late August or into September if some other feature is working with the waining monsoon.

Weather or not.