Thursday Morning Update

Thursday, July 5th 2012, 6:26 am
By: Alan Crone

Howdy friends!  Daytime highs will again move to near or slightly above 100 with sunshine and south to southwest winds around 10 to 15 mph.  The pattern will be changing soon bringing some storm chances  

The main interest continues to be the mid level ridge of high pressure and the model data suggesting this ridge will move westward during the next few days as a trough over the Northern Canada region also retrogrades.  This will open the gate for a cold front to slide over the area Monday bringing a round of showers and storms followed by near normal or slightly below normal readings.  This weekend a weak easterly type wave will slide underneath the ridge and bring a chance of late afternoon scattered showers and storms to extreme eastern Ok and western Arkansas.   

The temperatures today should be a degree or two warmer than yesterdays highs.  Some RAW model output suggests highs near 102 to 103 today with a one to two degree increase through the weekend.  This would place Saturday's highs around 103 to 105 as a cold front approaches locations to our north.  Moisture in the lower levels will also be increasing and this should keep the actual air temps from getting too out of hand.  I'll roll the dice and keep the Saturday high at 103, but reserve the right to change this number.  The temperature heat index values will also be increasing tomorrow through Sunday with an increase in the low level moisture across eastern OK.  This may require the issuance of another short term heat advisory for part of Eastern OK.  

Highs should drop significantly early next week due to the increase of cloud cover, some scattered showers, and eventually, the cooler air behind the surface boundary.  There's a chance we'll not get out of the upper 80s Tuesday and Wednesday, but I'll stick with highs around 90 along with northeast winds.   

Precipitation chances will remain around 10% for both Friday and Saturday across extreme Eastern OK due to the influence of the weak easterly type wave, but will move to near 30% Sunday.

 The front should arrive Monday and slowly sag southward into Monday evening.  This would mean the higher pops Monday with lesser pops Tuesday.  At this point, both EURO and GFS suggest the Wednesday period to be void of precipitation chances and I'll take the slight pop out of our package for Wednesday.  This active weather pattern will bring a break in the heat with morning lows in the upper 60s and highs in the upper 80s near 90.  

Tropical depression 4E is located about 620 miles south of the southern tip of Baja California and will move westward becoming a tropical storm either later today or tonight.  Again, this is a pacific basin storm.  There are no significant Atlantic basin systems this morning.