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FXUS63 KTOP 052337

Area Forecast Discussion
National Weather Service Topeka KS
537 PM CST Thu Dec 5 2019

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Friday)
Issued at 322 PM CST Thu Dec 5 2019

Upper low currently over the Four Corners region will continue to 
weaken as it moves east onto the Plains and towards the area 
tonight. At the surface, an accompanying cold front moving into 
northwest Kansas will continue to move south and east. This will 
lead to an increase in clouds this evening and overnight across the 
region. A spotty shower is still possible overnight south of I-35, 
near the track of the upper low, but most areas should remain dry. 

The cold front associated with the upper low will move through 
overnight, with an increase in northerly winds just behind the 
front. Behind the front, low level clouds will persist for portions 
of the morning, but skies will clear out in the afternoon as surface 
high pressure moves overhead. Despite clearing skies, cold advection 
behind the front will keep highs Friday in the low 40s.

.LONG TERM...(Friday night through Thursday)
Issued at 322 PM CST Thu Dec 5 2019

The weekend periods continue to look dry and warmer through there 
are a few minor things to monitor. Lee troughing behind the
exiting surface high under zonal flow aloft will lead to some 
gustiness in winds Saturday though impacts to fire danger look 
small with minimum RH values still well into the 40s and 50s. 
There is a decent signal for stratus development and perhaps 
persistence through much of the day Sunday as south to southwest 
winds return off the Gulf of Mexico which could impact highs 
Sunday. Have kept them in the low to mid 50s for now but this 
could be optimistic, especially in southeastern areas. A few 
solutions produce some very light and spotty precip in the stratus
but moisture depths and any forcing for ascent look too weak for 
any mention. 

A positive tilt shortwave moves southeast around the northern 
Canadian upper low Sunday night into Monday and crosses the central 
Plains. Moisture depths continue to look rather low for anything 
more than a slight chance for light precip with this wave, though 
much colder and windier conditions should occur by late Monday. 
Highs could occur early in the day and may not break freezing in 
some locations. Northwest flow persists into the mid week though a 
more zonal regime looks to set up by Thursday with little
opportunity for precipitation. There are some notable differences
in how much the cold air can be reinforced from the northwest in 
these periods. Have kept values on the cool side of normals at 
this point. 


.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 510 PM CST Thu Dec 5 2019

For the 00Z forecast period, FROPA will continue from northwest to
southeast backing winds to a northerly component at all sites by
about 05Z. Lagging stratus should reduce categories to MVFR
overnight until mid to late morning. Have some question on exact
bases but not expecting IFR CIGS for now. With the CAA could see
the winds gust also until mid to late morning.  



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