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Area forecast discussion 
National Weather Service Springfield MO 
258 PM CST Thursday Jan 8 2009 


Discussion... 


Currently...high pressure is working its way through the 
area...now centered over The Boot heel of Missouri. Winds are 
light and variable. Dewpoints have mixed out nicely with full sun 
today...which will make the low temperature forecast tonight 
rather tricky. Temperatures at this hour vary from the middle 30s 
over central Missouri to the middle 40s near the MO/Kansas state line. 


Tonight and Friday...southerly winds will gradually ramp up in 
speed tonight as high pressure continues to move off to the 
southeast. Low temperatures tonight will most likely occur this 
evening. A dry airmass and clear sky will lead to ideal 
radiational cooling conditions for a few hours. A very quick drop 
in temperatures into the middle 20s is expected over the Eastern Ozarks... 
the potential exists for it to be slightly colder. Over the rest 
of the area...temperatures will quickly drop into the upper 20s to 
middle 30s then level off as southerly winds will be the quickest 
to manifest in this area. 


Southerly winds will increase later tonight and Friday as the next 
area of low pressure approaches from the northwest. Winds will be 
gusty to around 30 miles per hour. Warm air advection regime will result in a pleasant day 
across the area...though moisture advection will lag a bit. 
Stratus will increase over southern Missouri during the afternoon 
hours and keep temperatures a touch cooler versus the remainder of the 
area. Highs will range from the 50s over the Eastern Ozarks to the 
60s over the remainder of the area. 


Friday night...aforementioned area of low pressure will push a 
cold front through the area. Confidence in precipitation with this 
front is on the low side. Low level moisture does return in the 
form of a stratus deck...though deep moisture is lacking. The 
better opportunity for scattered -shra will be over the Eastern 
Ozarks...though quantitative precipitation forecast will be on the order of a few hundredths of an 
inch. Behind the front...a strong cold air advection regime will quickly set up 
and send temperatures back down into the 20s with wind chills in the 
teens. 


Saturday and Sunday...quiet...dry and seasonably cold conditions 
can be expected. Aloft...northwest flow will take control of our 
weather regime. High pressure will dominate at the surface on Saturday 
with a clipper front expected for Sunday. Moisture looks sparse... 
though a snow flurry is not out of the question. 


Monday through Thursday...northwest flow will remain in place next 
week. The latest 12z suite of model output is coming into 
agreement that two solid pushes of Arctic air will be sent our 
way. GFS five wave charts indicate strong...deep troughing over 
the central and eastern Continental U.S.. as such...high pressure will 
accelerate southward into the middle of the nation sending 
temperatures well below average. There remains some minor timing 
differences regarding the exact timing of each frontal passage. 
Overall Monday into Tuesday will be the time frame for the first 
shot of cold with a the second...more substantial blast expected 
late Wednesday through Friday. As is typical with northwest 
flow...moisture will be hard to come by...but enough forcing 
should exist for occasional bouts of flurries from time to time. 
This cold blast is timed for our coldest time of the year... 
climatologically speaking. At this time...lows in the single 
digits and highs struggling to break 20 are possible for the 
latter half of next week. 


Gagan 


&& 


Aviation... 


VFR conditions will persist through Friday morning. We will see 
some middle level clouds increase this afternoon with bases averaging 
around 7000 feet above ground level. Mainly high clouds are then expected from 
this evening into Friday morning. We will have to closely monitor 
for stratus development from middle to late morning on Friday as 
moisture increases from the south. Thinking right now is most of 
the low clouds should stay east of the area...but could see some 
scattered low clouds at ksgf. Surface winds will steadily increase 
overnight out of the south and become somewhat gusty later Friday 
morning. Low level wind shear will also develop overnight and 
persist into Friday morning. 


Schaumann 




&& 


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


$$