Scientific Forecaster Discussion

NWS Discussion
			
				

Area forecast discussion 
National Weather Service Kansas City/Pleasant Hill MO 
557 am CDT Thu may 23 2013 


Short term...(today through saturday) 
issued at 325 am CDT Thursday may 23 2013 


Light rain showers/sprinkles have been moving south through Iowa 
early this morning around the upper-low moving across the upper 
Mississippi Valley. There is a chance that these could last into 
northern and northeastern Missouri this morning, so have added a 
mention of sprinkles. Otherwise, quiet conditions are expected with 
thicker stratocu persisting through much of the day across northern 
and northeastern Missouri. This area will see highs in the mid 60s as 
cloud cover and continued cool northerly/northeasterly winds keep 
temperatures seasonally cool. Southern and western portions of the 
forecast area will see temperatures in the lower 70s as cloud cover 
will be less persistent there. 


Friday should be a bit warmer across the area but temperatures are 
still expected to be in the lower 70s. The next decent chance for 
rain will come late Friday night and into Saturday. A strong 
low-level jet is expected to develop over the plains, focusing on 
western to central Nebraska and Kansas. This will likely trigger 
storms across the region and as the low-level jet veers and shifts 
east, the focus and stronger, moist isentropic ascent will as well. 
This may bring whatever forms in the plains into mainly northern 
Missouri late in the night. We will also be seeing more broad 
isentropic lift through the area earlier in the night, so cannot 
rule some isolated showers or storms out earlier. But the best 
chances will be later when better moisture and ascent arrive. 


Mid-level flow will become more persistently from the south to 
southwest allowing continued moisture advection into the region. 
This will result in at least a chance for thunderstorms through the 
day and into the overnight. While it doesn't look like the start of 
the Memorial Day weekend will be a washout with thunderstorms 
everywhere, the chances will be there throughout the day for 
scattered showers and storms unfortunately. The threat for severe 
weather looks low at this through Saturday night as shear and 
instability will be rather limited. 


Long term...(sunday through wednesday) 
issued at 325 am CDT Thursday may 23 2013 


Upper-level ridging will remain in place across the central U.S. For 
much of next week. Despite this ridge, all medium range guidance 
continues to produce multiple rounds of convection across the plains 
into the upper Midwest through most of the extended period as the 
upper trough to the west sends continuous weak impulses into the 
region. Airmass in place will be somewhat unstable, so several 
rounds of thunderstorms are certainly a possibility, but the 
presence of weak capping aloft and the lack of any well-defined 
forcing mechanism suggest these model pops are probably overdone. 
While it is unlikely we will see thunderstorms every day next week 
like the models suggest, its not yet possible to pinpoint when/where 
the highest chances will be. Therefore kept low-end chance pops for 
much of the extended period but tried to trend drier by Wednesday as 
upper level heights begin to rise overhead. Wind fields will be weak 
so significant severe weather seems unlikely at this point. 


&& 


Aviation...(for the 12z tafs through 12z Friday morning) 
issued at 545 am CDT Thursday may 23 2013 


MVFR ceilings are expected through early this afternoon. And based on 
upstream observations and model guidance, there will likely be 
several hours of fuel-alternate MVFR cigs from late this morning 
through early afternoon. Winds will shift from the northwest to the 
northeast through the day but should generally be light. Ceilings are 
expected to break up and scatter out by late this afternoon. Once 
this occurs skies should remain clear to mostly clear through the night. 


&& 


Eax watches/warnings/advisories... 
Kansas...none. 
MO...none. 
&& 


$$ 


Short term...cdb 
long term...hawblitzel 
aviation...cdb