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fxus63 kdvn 110745 
afddvn 


Area forecast discussion 
National Weather Service quadrant cities Iowa Illinois 
245 am CDT Sat Oct 11 2008 




Synopsis... 
southerly flow will allow temperatures to climb above normal across 
the region for the weekend. A storm system developing in the plains 
is expected to affect the area the first part of next week. High 
pressure building in behind the storm system will bring cooler than 
normal temperatures for the second half of next week. 


$$ 


Short term...today and tonight... 
quiet and warm weather expected for the next 36 hours as southerly flow 
continues across the area. Current high clouds to clear the area 
during the morning but models indicate relative humidity to increase again in the 
afternoon/overnight time frame. Thus only expect a gradual increase 
in high clouds today/tonight. High temperatures to be a little warmer than 
yesterday and mins tonight a bit warmer than this morning. ..08.. 




Long term...Sunday through next Friday... 
..warm early October weather to continue into Sunday night...Then 
showers and storms Monday afternoon into Wednesday night with next 
slow moving front... 


Average model initialization with convective feedback problems with 
upper low and moisture plume from hurricane "norbert". This suggests 
impacts to phasing energy with system beyond 36-48 hours all 
solutions...especially NAM-WRF and GFS. Hi-res European model (ecmwf) overall best on 
moisture and used with inputs of thermal and kinematic fields of GFS 
and NAM-WRF through Sunday night. Then primarily weighted toward hi- 
res European model (ecmwf) and UKMET. 


Sunday night through Monday night...skies to become partly to mostly 
cloudy with lots of high level moisture ahead of next system to keep 
highs Sunday in middle to upper 70s to around 80f. Clouds...kept mins 
Sunday night in lower 60s with some middle 60s possible for later shifts 
to consider. Kept dry as forcing still well to SW and west. Monday... 
highs of middle to upper 70/S expected ahead of front for southeast 2/3 with 
lots of filtered sunshine. Due to clouds...appears highs will not 
push past 78f and this an issue for later shifts to monitor. Some 
potential with October sun if thicker clouds...then highs may need 
trimming. Most probability of precipitation to occur along and behind front which doesn/T 
arrive until Monday PM and have delayed probability of precipitation accordingly. If front 
is even slower...highs in northwest 1/3 may need upping. High clouds to 
limit instability with just showers and a few embedded storms in PM 
that will stay below severe levels into Monday evening. Likely probability of precipitation 
west to high chance east sections with mainly moderate amounts of 
precipitation expected as front passes with some embedded storms. 
Phasing of upper energy from South Branch of ejecting upper low with 
front still a major issue for later shifts to reassess. 
Conceptually...appears South Branch energy to be stronger than most 
solutions a concern. 


Tuesday and Wednesday...timing of southern energy lifting along slow 
moving front remains a question for day shift to reconsider. Kept 
skies mostly cloudy with high chance to to likely probability of precipitation with cooler 
temperatures. Main issue is precipitation and clouds impacts on 
highs and lows and went middle of Road with guidance but highs 
Tuesday and Wednesday may need trimming if more rain falls due to 
evaporative cooling from upglide over front. 


Thursday and Friday...no changes made. Prefer trend of northwest flow 
to keep area near to below normal with some risk of cool rain 
late Friday with next digging upper level wave. ..Nichols.. 


&& 


Aviation... 
VFR weather expected through Saturday night. Models indicate only an 
increase in high clouds expected through sunrise Sunday. 88d VAD 
profile indicates winds at 1kft are around 15 knots which is weaker 
than yesterday so low level wind shear should be a non-issue. Wind direction will be 
southeast which is a climatological favored direction for fog 
development at kdbq/kmli. However...dry ground should prevent visibilities 
from dropping below 6sm tonight. ..08.. 


&& 


Dvn watches/warnings/advisories... 
Iowa...none. 
Illinois...none. 
MO...none. 


&& 


$$ 


08/Nichols