|George R. Kasica
Tucson, Arizona Climatology
As you can see on the map below the city of Tucson, Arizona is located on a valley plain about 15 miles in diameter at the base of the Catalina Mountains. The mountains rise to over 5,000 feet on the north, east and south sides of the city and to about 4,000 feet on the western edge.
The area around Tucson, Arizona in February and March (the period for which we were forecasting was from February 26 to March 9, 2007) typically experiences high temperatures in the low 70's and lows in the middle 40's. Precipitation is very sparse with the average day receiving only about about 0.03" of liquid precipitation. Looking at the extremes for the high and low temperatures in the detailed table you can see however that temperatures have reached to the mid 90's for a high and been as cold as the mid 20's for low temperatures. So while you might expect extreme heat in the area given its desert reputation, it is also not unheard of for it to see extremely cold temperatures as well.
The large variations in normal high and low temperatures in the Tucson area, by as much as 30 degrees from low to high on a daily basis, are a direct result of the strong heating effects of the sun under the usually clear daytime sky and the equally rapid cooling under clear nighttime skies and light wind conditions. The area around Tucson actually receives more sunshine on a yearly basis than any other area in the United States and you can see the result of this in the wide range of temperatures and relatively low precipitation totals mentioned above. Coincidentally it also has one of the highest number of clear nights as well, a fact along with it's tall mountain peaks that led to the construction of the Kitt Peak National Observatory not far from the city (about 50 miles to the southeast) in 1958. Over the years it has become a location that contains the most extensive array of optical telescopes for solar and celestial observation on Earth.
Most of Tucson's precipitation (over 50%) comes during it's rainy season of July 1 to September 15 and another 20% is received during the period of December through March. A portion of which is when we were forecasting for.
Winds in the Tucson area are also normally quite light and follow a typical daily pattern of starting out the early morning hours from the southeast as shown below and then throughout the day gradually switching to the northwest before retuning to the southeast as night falls once again. The strongest winds tend to occur from the southwest and southeast as you can see below. Also, you can see there are not major differences in the directions or speeds for the two months below, and as a matter of record, more or less the entire year follows a similar pattern as these two months in terms of direction, speed and time of occurrence.
(February and March prevailing wind directions courtesy of
National Resources Conservation Service - click pictures for full size
As you can see the above items show clearly that the climate of Tucson Arizona, while not extreme as other cities we've forecasted for such as International Falls, Minnesota it still can offer significant challenges in terms of temperature extremes and precipitation predictions