The maps on the right, courtesy of the Ok Mesonet, show very graphically how dry most of our state is. The first map shows the total precipitation so far this calendar year and the second shows the percentage of normal for the calendar year. Clearly, the western 2/3 of the state is below normal with some of the far western counties at less than 20% of their normal precipitation for the year. This does not bode well as we are past our ‘wet season' and into the time of year in which the hot summer weather leads to high evaporation rates and a further expansion of drought conditions.
And speaking of hot, this June so far is the second hottest June on record, second only to the record setting June of 1911. That particular June had 18 days at or over 100 so it was particularly brutal during the day. But, it is interesting to note that this time around, June of 2011 is averaging even warmer at night than did June of 1911. There are several reasons for this, not the least of which is the much larger urban area and all the concrete and asphalt that goes along with the larger metropolitan area of today. This leads to the well known urban heat island which is most evident during the overnight hours.
Having said all that, the heat just goes on as far as our forecast goes. Temperatures today and tomorrow will be on the order of 10 degrees warmer than normal both at night as well as during the day. Our rain chances will be in the slim to none category till Tuesday night when a weak cool front will arrive. Right now, the latest guidance suggests the front will be reaching the I-44 corridor along about 10-11 PM Tuesday evening and then on through the state by Wednesday morning.
Gusty southerly winds today and tomorrow ahead of the boundary will shift to a more NE direction for much of the day Wednesday. This will provide at least a brief break in the excessive heat. The boundary should also set off at least some shower and storm activity although the surface winds are not particularly favorable for a widespread rainfall event. The convergence along the front does not look very impressive up to this point, so we will keep the chances on the order of 30% for Tuesday night and into the day Wednesday. Some of these may become severe with winds and hail the primary threats.
After that, hot and humid conditions return for the latter part of the week. Also, conditions aloft will be supportive of at least a slight chance of a shower or storm on any given day so we will carry a 20% chance of rain and keep our fingers crossed. Keep in mind, although the chances are in the slight category, those storms that do form in this kind of environment will be capable of dropping some pretty good rainfall totals in a short period of time.
So, stay cool, stay tuned, and check back for updates.