A Weak System Soon


Friday, September 9th 2011, 5:40 am
By: News On 6


What a week we have been experiencing in the weather arena.  Talk about a break.  We have gone from 108 to 78 for highs in less than two weeks.  But we have plenty of summer left.  The pattern is suggesting a possible return to some lower or mid 90s by early next week.  The next weather maker for our area is clearly seen via vapor imagery near the Illinois-Iowa region.  This spin the atmosphere is the former Tropical Storm Lee.  It is now "cut off" from the upper air flow and is slowly retrograding into the Missouri and Tennessee Valley areas.  This feature will give us a slight chance of showers and storms late tonight and Saturday before the low begins to rapidly weaken and form more of an open wave.  

The NAM is pretty consistent with a precip signal for later tonight across the southern Kansas and extreme Northern OK areas, while offering a chance of scattered storms Saturday afternoon and evening across the NE part of the state.  We should see an increase of cloud cover from the northeast within the next 6 to 12 hours with mostly cloudy conditions expected overnight and Saturday.  This should keep the temps down into the lower 80s Saturday. 

The mid level ridge of high pressure currently to our southwest will be nudging back into the region soon bringing a return of lower 90s Monday and mid 90s Tuesday.  The surface air flow will return from the south and this will attempt to bring additional low level moisture back into the region ahead of a cold front scheduled to arrive Tuesday night or Wednesday morning. 

 The GFS has been overly aggressive with the moisture, but may not be able to model the lower levels correctly due to the tropical system currently in the southern Gulf region.  The GFS and EURO have had big differences regarding the outcome of this system, and the jury remains out at this hour.  The EURO of two days ago was taking the storm to Louisiana but backed off the solution yesterday.  The official NHC forecast has the system moving westward in the next 3 to 5 days.  A quick glance at some of the hurricane models this morning indicates a westerly track.

 The last runs of the GFS and EURO both suggest a strong front will arrive Tuesday night into Wednesday morning bringing cooler air back to the state along with a chance of some post frontal precipitation.  The EURO tends to wash out the boundary late next week while the GFS keeps it south of the area and brings a large area of rain to the region Thursday.  The jury is still out, but I have lowered the highs for Wednesday and Thursday from previous forecasts but I have not increased the rain chances at this point in the forecast cycle.