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652 AM CDT Thu Oct 23 2014

Updated aviation section for 12z tafs


.SHORT TERM...(Today through Saturday night)
Issued at 335 AM CDT Thu Oct 23 2014

Main concerns early this morning are patchy frost and fog. The 
coldest temps so far have been in the mid 30s across parts of 
southern Illinois...from the kmvn/kmdh corridor east to Harrisburg. 
Temps elsewhere were still in the 39 to 44 degree range at 08z. For 
most of our appears frost coverage will be patchy this 
morning. As far as the fog...there has not been any dense fog so 
far...but there will likely be some dense fog patches around 
sunrise. Added mention of patchy fog to zones/grids for early this 

Satellite indicates mid and high clouds over western Missouri and 
Arkansas are making steady eastward progress. This cloudiness is 
associated with a weakening 500 mb shortwave trough that will reach 
the Mississippi River this afternoon. Very dry air in the low levels 
/associated with the surface high over our region/ will negate any 
mention of precip today. Model high temp guidance has been running a 
little too cool on recent will keep forecast highs a 
degree or two above mos.

During the night tonight...another shortwave trough will move 
quickly southeast across the Great Lakes into the Ohio Valley. This 
system will keep some mid and high cloudiness over our region. Temps 
will be milder due to the clouds and light southwest winds behind 
the retreating surface ridge.

On Friday...light southwest winds and clearing skies should combine 
to push high temps to at least 70 degrees in much of our region. The 
relatively mild conditions will continue Friday night.

On Saturday...model guidance is in good agreement that a weak 
surface cold front will move southeast across our region. The nam is 
the most aggressive with moisture return ahead of this front. The 
nam indicates some light precip will accompany the front...but it 
remains an outlier. Will keep the forecast dry...but a band of low 
cloudiness is likely to precede or accompany the front. Given the 
warm start to the day and increasing afternoon sunshine...guidance 
highs in the mid to upper 70s look reasonable. Cooler and drier 
conditions will arrive behind the front Saturday night. 
.LONG TERM...(Sunday through Wednesday)
Issued at 335 AM CDT Thu Oct 23 2014

The long term is based on a blend of the latest and previous 
ensemble means from the GFS and ECMWF. This should minimize any 
model errors and discrepancies in handling more specific features 
within broad progressive w/e flow across the conus. Moderate run to 
run issues exist with the operational runs of the GFS and ECMWF.

Sunday and Monday should be dry with above normal temperatures. SW 
flow aloft will develop, while a warm front lifts north of the 
region. By 18z Monday, a strong high should cover the Atlantic 
states and coast with low pressure over the upper Midwest, and a 
trailing front into the southern high plains. No precip with a very 
dry airmass over the region.

Tuesday, energy aloft will move out of the nations mid section, 
accompanied by the arrival of a modest cold front. Think most of 
Monday night will be dry. However chances for showers increase
substantially Tuesday. As the energy moves NE, with the surface
low moving north of the Great Lakes, the movement of the boundary 
and progression of forcing and moisture should slow. Carried higher
PoPs into Tuesday night, then lowered them from NW to SE Wednesday, 
dry for now Wednesday night. Have added a thunder mention as 
instability parameters suggest the possibility.  


Issued at 652 AM CDT Thu Oct 23 2014

Shallow ground fog will burn off quickly after sunrise. Mid and high 
clouds will increase later this morning and this afternoon...but 
cigs will be above 10k feet. Winds will be light as surface high 
pressure holds sway through this evening. The potential for fog 
appears lower tonight due to mid and high cloudiness...but some 
shallow ground fog is possible if clouds become scattered. 




Short term/aviation...MY
Long term...CTN

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