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Area forecast discussion 
National Weather Service Springfield MO 
504 am CST Monday Nov 23 2009 


..update to aviation... 


Discussion... 


Forecast challenges continue to deal with temperatures through the 
week along with precipitation timing this evening as next storm system 
appears to be slowing down some. 


Currently...area still under the effect of surface ridging that 
extends from a surface high located over the Great Lakes area. 
Surface winds remain out of the southeast this morning and the 00z 
sgf sounding...lower layers remain fairly dry. There is some low 
level moisture though slowly streaming north into south central 
and southeastern Missouri that will need watching through the day. 
Do believe though...that most of this will remain south of the County Warning Area 
with not much of an impact. Two shortwaves seen on water vapor 
imagery. First just approaching eastern Kansas and will make its 
way through the County Warning Area this morning. The second...and more potent 
shortwave...currently moving southeast into western Wyoming and 
northeastern Utah. 


For today...a pleasant day on tap once again with dry conditions 
through the day. First shortwave that will move through the area 
this morning will drop 850/925mb temperatures several degrees over 
yesterday. With variable cloudiness and periods of 
sunshine...should still see temperatures climb back into the low 
60s once again today. GFS coming in about 6 hours slower on precipitation 
with the second shortwave this evening...now showing onset of 
precipitation moving into southeast Kansas and western Missouri 
after midnight tonight. European model (ecmwf) even slower with low...bringing 
precipitation into southeast Kansas and western Missouri more towards 
Tuesday 12z. Slower onset of precipitation should help overnight lows to 
remain warmer than guidance and have gone a few degrees over mav 
MOS forecast. Instability still looks meager with this 
front...though upper jet still fairly strong...so will continue 
mention of thunderstorms in the forecast for overnight. 


Bulk of precipitation looks to move through the area Tuesday 
morning into the afternoon hours. With fairly quick progression of 
low through the area...thinking is that we should see maybe a 
widespread quarter to a half inch of rainfall with this system with 
rain exiting east by Tuesday afternoon. Wrap around moisture 
behind the low may give US some drizzle into the evening hours 
before 850mb thermal trough moves through around midnight 
Wednesday morning. 


Clipper system still looks on track for Wednesday night into 
Thanksgiving day with 850mb temperatures dropping to -6 to -8c 
behind the system and staying with US through Friday morning. 
Highs will struggle to reach the low 40s with overnight lows into 
the middle 20s expected both Thursday and Friday mornings. Start to 
see a warm up commencing Friday afternoon as surface ridge passes 
through and low level winds shift to the southwest Friday evening. 
By Saturday...upper ridge forecast to be overhead with 850mb 
temperatures climbing back to around +8/+10c across southwestern 
Missouri. Warmer and dry conditions expected for the weekend with 
highs in the upper 50s to low 60s. 


Claycomb 




&& 


Aviation... 


For the 12z tafs...satellite imagery shows stratus field beginning 
to increase and believe this trend will likely continue this 
morning. Have ceilings generally between 3500 and 5000 feet much 
of the day with ceilings dropping into IFR category this evening 
in advance of approaching shortwave. Low level wind shear will 
also be possible overnight with the approach of the shortwave. 


Lindenberg 


&& 


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


$$