Area forecast discussion National Weather Service quadrant cities Iowa Illinois 1248 PM CDT Thursday may 23 2013 Synopsis... issued at 253 am CDT Thursday may 23 2013 Deformation zone moving south across area at 2 am with areas of mostly light rain and drizzle noted. Dubuque though in past 2 hours has picked up .23 inches. AWIPS distance and time feature shows end of precipitation to pass quickly across area between 11-16z. Upper air and surface shows seasonably strong and cool Canadian air mass to move in with below normal temperatures next 24 hours and then unsettled weather into early next week with waves along stalled front to our southeast. && Short term...(today and tonight) issued at 253 am CDT Thursday may 23 2013 Today...use of Nowcast tools supports light rain and patchy drizzle to slide southeast by middle morning. Skies should clear from north to south between 14-21z as strong subsidence and cooler and drier moves in. Northerly winds will be breezy at 15 to 25 miles per hour into late afternoon as highs reach mostly into the middle 60s and some lower 60s in the east and northeast. These temperatures are about 10 degrees below normal. Tonight...clear skies...strong subsidence and calm winds by early overnight hours will allow for strong decoupling of bl and mins in the northeast 1/3 area to see upper 30s with isolated cold air drainage spots possibly seeing middle 30s with patchy frost risk. This is the main concern for day shift to reassess. Mins will be within 2-4 degrees of records at mli/dbq (see climate section below). Nichols Long term...(friday through wednesday) issued at 253 am CDT Thursday may 23 2013 Dry and cool conditions will be seen Friday with temperatures below normal. Initially...Friday evening will be dry. Return flow aloft is prognosticated to bring moisture back north into the Midwest. Schc probability of precipitation were placed in the extreme western part of the County warning forecast area during the late evening hours. The better low level jet and moisture return is still west of the County warning forecast area at midnight. The mesoscale convective system/lift tools generally suggest something just west of the County warning forecast area at midnight that should stratify out due to the dry air over the area. After midnight...the low level jet veers into the County warning forecast area with a respectable Theta-E gradient moving across the area. Internally...the models are indicating significant evaporative cooling due to the dry air feeding in from the east. Thus the mesoscale convective system that forms in the plains would stratify out as it moves into the area. The extreme west/southwest would have the best potential at seeing a thunderstorm while the remainder of the area should see showers. Saturday will be extremely cool with mainly stratiform rain across the area as strong evaporative cooling continues. Any thunder would be across the extreme southwest/south parts of the County warning forecast area as the nocturnal mesoscale convective system continues to decay. Saturday night the next disturbance will develop an mesoscale convective system in the plains that tops the ridge into the area. Again relatively dry air feeding in from the east should result in the mesoscale convective system stratifying out as it reaches the area. Any thunder would be isolated and across the south third at most. Sunday on... the model consensus continues an active weather pattern across the Midwest with numerous disturbances topping the upper ridge over the area. The overall set up is comparable to a middle Summer ring of fire. Thus mesoscale convective system events are expected to develop and move into the area at night with the mesoscale convective system decaying across the area during the day time. Boundaries left over from each mesoscale convective system event will provide the focus for diurnal convection during the afternoon and evening. The model consensus has chance probability of precipitation from Sunday through Wednesday reflecting this scenario. There will be periods of dry weather but they cannot be resolved due to smoothing of the model features. Temperatures will remain below normal on Sunday followed by moderating temperatures Monday through Wednesday. 08 && Aviation...(for the 18z tafs through 18z Friday afternoon) issued at 1235 PM CDT Thursday may 23 2013 Some lingering MVFR ceilings through 20z...otherwise cumulus field should continue to lift through VFR levels and mix out/decrease through early evening. North to northeast winds of 10-15 kts with higher gusts to become light easterly by late evening as Canadian high pressure takes hold from the north. Drier boundary layer influx from the north/NE should also inhibit much of any fog development tonight except in river valleys away from the taf sites. Mainly clear and VFR for much of Friday. ..12.. && Climate... issued at 253 am CDT Thursday may 23 2013 Record lows for may 24... Moline.........36 in 1925 Cedar Rapids...34 in 1925 Dubuque........35 in 1925 Burlington.....38 in 1925 && Dvn watches/warnings/advisories... Iowa...none. Illinois...none. MO...none. && $$ Synopsis...Nichols short term...Nichols long term...08 aviation...12 climate...Nichols