Some Rain with Cooler Air

Thursday, September 15th 2011, 5:23 am
By: News On 6

A cloudy and cool afternoon is expected across the state with highs in the lower 60s.  Some showers will be possible but not for all locations. 

 The radar indicates several areas of rain and isolated thunder this morning across portions of the state.  Our rain and storm chances will remain around 50% to 60% for today.   

 The second surge of cool air is moving across the region this morning with northeast breezes and mostly cloudy conditions.  A weak upper level system will be moving near the area today and will attempt to bring some showers back to the region. The models have been very inconsistent with the precipitation forecast for this event and the lower levels of the atmosphere will make for a tricky temperature forecast.  Dry air at the surface may inhibit precipitation amounts for the first hour or so of any area that experiences the precip potential. If the showers become widespread in the form of steady rain, a process of wet bulbing will take place allowing the temperatures to drop into the upper 50s.  The RAW NAM data for the past two days indicate a very unlikely but still possible scenario of temps dropping into the mid 50s across extreme northern OK with widespread rain.  The GFS and EURO surface T plots have been consistent with highs today in the mid and upper 60s, but these data have not been consistent regarding the precipitation forecast.  Needless to say, we have some confidence issues regarding the "exact" temperature for the afternoon highs across northern OK, but a much cooler reading will occur today regardless of the outcome.  At this hour, I will go with a high near 63 for Tulsa with some locations in central and western OK in the upper 50s.  Locations across extreme eastern OK should make the upper 60s.

 The extended data continues to offer varying solutions regarding the weekend but the most probable includes a retreating warm front Saturday into Sunday with a chance of showers and storms Saturday morning along and north of the boundary.  This would place Tulsa in a favorable position for morning storms before the boundary lifts northward into southern Kansas Saturday afternoon.  Sunday evening another upper level system is expected to move near the region and additional storms would be possible Sunday evening into Monday across the state.

 Today's activity will not be severe but storms this weekend into early next week would have at least a slight chance at becoming strong to severe due to the influence of southerly winds, increased low level moisture, and slightly better upper air support early next week. 

 The next frontal passage will more than likely occur around the Tuesday or Wednesday period of next week, but this air mass appears more to be of pacific origin and should not be a significant cool down.  The EURO is now faster with the fropa compared to the GFS.  We'll make no big changes to the extended but some changes will be likely as we get closer to next week.  Temperatures next week will be closer to normal with highs in the mid 80s and lows in the mid to upper 60s.