Tucson Weather

May was Cool and Dry. Don’t get used to it!

Saguaro in Bloom, May 8, 2010

Saguaro in Bloom, May 8, 2010

The numbers are back from the National Weather Service office in Tucson and the numbers show what you already know.  May was nice and cool.  Almost a full degree below “normal.”  It was dry too.  Only .02″ fell at the official rain gauge at the International Airport, .22″ below normal.

The cool May continued the streak of a cool year so far.  For the first time since 1988 the average temperature through May in Tucson was below normal and May was the 4th month in a row below normal as well.

You can read the entire summary here.

Now the bad news.  This Summer is likely to heat up.  The National Weather Service says there is a good chance that we will be hotter than normal this June, and this Summer, with equal chances of normal rainfall during Monsoon.  AccuWeather.com is also predicting a hot Summer pretty much for all of the country except maybe the West Coast and the Northern Plains.

As for our Monsoon, the National Weather Service office released this forecast a few weeks ago.  Assuming that the Pacific flips to a La Nina this Summer I think we will see a slow start to Monsoon with an active finish!  We may end up with normal, or above normal rainfall, with periods of heavy rain in August and September.  I hope that forecast bears out.

Joe Bastardi with AccuWeather and others are calling for a very active Hurricane Season in the Atlantic.  The Gulf of Mexico is warming quickly and the coming La Nina in the Pacific will negate the shear that comes with El Nino years.  Bastardi is already calling it the Hurricane Season from Hades and we haven’t seen any activity yet.  The good news is a couple of hurricanes in the Gulf of Mexico may actually help disperse the oil from the BP oil spill!

Joe Bastardi is also predicting a lot of melting ice in the Arctic this Summer.  Folks will likely point to that as more evidence of Global Warming.  However, the Pacific Decadal Oscillation has entered a cold phase.  La Nina and a cold Pacific for the next year and a half will bring the ice back in a hurry and the country will be cold and colder the next two Winters.  Time will tell.

El Nino on the Wane, Monsoon Lovers Delight?

(I posted this yesterday on the Tucson Weather Facebook page)

Last Summer’s Monsoon got off to an early start but was ultimately thwarted as El Nino kicked in. The weather pattern marked by warming waters off of the equatorial Pacific caused a persistent area of high pressure to form over northern Mexico. Southern Arizona missed out on much of the best time of the year and the rains that come with it.

However that all changed this past Winter. The same El Nino brought not only beneficial rain to the desert, but TONS of mountain snow that is still running off. Those Winter, and now Spring, showers have brought beautiful desert flowers. Allergy sufferers are suffering, and hikers are fawning, as flora and fauna are full of life.

But what of this Summer? Will we repeat the misery of a mostly missed Monsoon? I say probably not. The good news is the El Nino currently in place is weakening. Most of the computer models now show ENSO neutral (no El Nino nor La Nina, aka “normal”) conditions by Summer. That should mean a return to a “normal” pattern in time for Monsoon.

The bad news is some of the models are indicating that we may see La Nina conditions by next Winter. La Nina Winters around here tend to be warm and dry, so I hope that doesn’t happen. However, as the Pacific Decadal Oscillation returns to a cold phase we can expect more La Nina’s than El Nino’s over the next 25-30 years.

In the meantime, we are still in somewhat of an El Nino Winter pattern. An unusually cold and strong storm (for this time of year) is moving in Wednesday. We may even see some high elevation snows from this one!

One thing about the weather, it’s always oscillating!

Read more about it: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.html

Tucson Weather