Area forecast discussion National Weather Service Kansas City/Pleasant Hill MO 412 PM CDT Wed may 22 2013 Short term...(this evening through Friday afternoon) issued at 408 PM CDT Wednesday may 22 2013 The forecast area will remain under the influence of a seasonably cool and dry cyclonic flow around a nearly vertically stacked low pressure system now over eastern Iowa. A secondary cold front with another surge of cooler air is expected to drop south across NE and Iowa later this evening and through the County Warning Area overnight. Considerable cold air stratocu will begin to scatter out across the southwestern County Warning Area this evening but much slower over the rest of the region. The far northern counties will likely remain under a blanket of clouds through the night. The stratocu will likely hang around over the County Warning Area for most of the morning before finally scattering out. Temperatures through h8 will be similar to today but should have the benefit of afternoon sunshine to support warmer readings than today. Favored the slightly cooler mav MOS guidance due to the north to northeast surface winds. A surface high building south through the Great Lakes Thursday night into Friday will maintain a pool of cool air that will be drawn westward on Friday. This will keep temperatures below average for a third day. An amplifying upper level ridge will press eastward through the plains on Friday which will allow warm air advection aloft to spread increasing mid and high level cloud cover towards MO. However, the easterly boundary layer winds will maintain a cool and dry fetch such that not overly impressed on rain chances through Friday. Best one could hope for are sprinkles or a brief afternoon shower over northwest MO. Long term...(friday evening through wednesday) issued at 408 PM CDT Wednesday may 22 2013 The forecast for Friday night and on through the Holiday weekend into next week remains relatively unchanged with a prolonged period of unsettled weather. By Friday evening models advertise a shortwave ridge having migrated into the plains, where it will linger through the weekend into next week as it remains stuck between troughs anchored across either coast. Thoughts are this blocking pattern will hold steady as advertised, thus allowing temperatures to rebound slowly into early next week. This will keep temperatures around normal through the weekend, slowly lifting them into the 80s early next week. Major issue for the Holiday weekend will be the potential for storms. Shortwave ridge, as mentioned earlier, will be a persistent feature over the region. Shortwave troughs moving through, or ejecting from, the larger synoptic West Coast trough will spend the next several days riding up and over the ridge. These small perturbations will have the potential to bring repeated rounds of rain as they are swept over the ridge. At this time, confidence is highest that stormy activity will occur Saturday as the first of many ejecting troughs sweep through the region. Therefore, have kept the focus for likely pops on Saturday. Confidence generally drops off in the later periods though this is mostly due to the uncertainties of antecedent convection; depending on whether a boundary has been left across the region and/or where available moisture will be. However, with the ridge not moving much, and a endless parade of shortwave troughs looking to exit the West Coast over a plains states ridge, thoughts are storms will be possible throughout the later periods. Have left the latter half of the forecast broad brushed with chance pops as a result. Otherwise, the potential for severe weather continues to look very low owing to a mismatch between shear and instability in these outer periods. && Aviation...(for the 18z tafs through 18z Thursday afternoon) issued at 1235 PM CDT Wednesday may 22 2013 Cold air advection tied to cyclonic circulation around deep low over Iowa will maintain large area of MVFR cigs across northern/central MO and northeast Kansas through mid afternoon. Mixing should allow cigs to rise to low end VFR later this afternoon and continue through tonight. Low level moisture should remain plentiful and BUFKIT soundings and condensation pressure deficit progs indicate another southward surge of MVFR cigs out of Iowa/northern MO will push into the terminals Thursday morning. Any instability showers this afternoon should remain north of the terminals over northern MO and dissipate a few hours after sunset. && Eax watches/warnings/advisories... Kansas...none. MO...none. && $$ Short term...mj long term...mj/cutter aviation...mj