522 
FXUS63 KTOP 071744
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
1244 PM CDT Sun Apr 7 2019

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 334 AM CDT Sun Apr 7 2019

Early this morning the mid-level trough axis was pivoting 
northeastward across the outlook area.  While the main line of 
showers and storms exited to the east early this morning, another 
batch of scattered showers and storms on the backside of the trough 
axis was tracking into north central KS.  There is still uncertainty 
with regards to whether or not this scattered precipitation will be 
able to sustain itself across the CWA, but it's worth noting that 
06z and 07z runs of the HRRR/RAP show it holding together and 
tracking eastward along the I-70 corridor through sunrise before 
dissipating. As a result, have kept some slight to low-end chance 
PoPs in the forecast through that time.  Where precipitation has 
cleared out, areas of fog have developed due to last evening's 
rainfall and the calm winds in place.  Reduced visibilities of 1/4 
mile to 1 mile have been common, so will need to continue to monitor 
these reduced visibilities to see if areas of dense fog become 
widespread enough to warrant the need for a Dense Fog Advisory.  

While models show the surface cold front still tracking eastward 
across the CWA this morning, model soundings do not show much in the 
way of residual moisture behind the exiting mid-level trough.  As a 
result, have trended a little faster with diminishing PoPs and have 
a dry forecast by mid morning.  While surface winds should veer to 
the west and northwest late morning through this afternoon, there 
doesn't look to be much in the way of colder air behind this front. 
As a result, expect deep enough mixing to occur to once again boost 
high temperatures into the middle 70s across much of the CWA as 
skies become mostly sunny through this afternoon.  Surface high 
pressure will quickly track south of the area tonight into Monday, 
causing winds to back to the southwest once again.  However, these 
winds will be very light, so combined with mostly clear skies 
anticipate decent radiational cooling to support cooler temperatures 
with lows into the mid/upper 40s.  

.LONG TERM...(Monday through Saturday)
Issued at 334 AM CDT Sun Apr 7 2019

A weak front associated with a modest wave moving across the 
northern Plains passes through in the afternoon but should have 
little impact on highs reaching the middle to upper 70s with only 
some afternoon cirrus to hinder insolation. Model differences begin 
to increase Tuesday with differences in handling shortwaves rotating 
around an eastern Canadian low impacting how fast the modest surface 
ridge exits to the east and local low-level winds. With cirrus 
likely to increase downstream of the approaching upper trough, this 
could have notable impacts on temps. An average approach produces 
highs in the mid 70s to lower 80s. 

Solutions with the faster exit to the low-level ridge bring the 
entire area well into the warm sector of the developing cyclone 
Wednesday while northern and western locations struggle to see deep 
mixing in the slower solutions. Plenty of mid-level warm-air 
advection Tuesday into Wednesday keeps surface-based convection 
unlikely with the associated front's/fronts' passage Wednesday into 
Thursday so the main impact with the warm sector location Wednesday 
will be on wind speeds (possibly near Advisory levels) and thus fire 
weather with Very High RFD category possible in a better-mixed 
scenario. The system is now back to a more progressive state and 
brings strong cold-air advection Wednesday night into early Friday 
with much greater potential for deformation precipitation to impact 
at least northern locations as well as more Wind Advisory potential 
as the roughly 985 mb low exits to the east-northeast Wednesday 
night into Thursday. The CAA results in snow potential (likely 
light) in northeastern areas as the precip exits Thursday night. 
Temperatures both Thursday night and Friday night could pose a 
hazard to early vegetation with lower 30s quite possible. 

There is fairly good model agreement in the next upper wave emerging 
from the southwestern states next weekend. The window for 
temperatures to recover significantly bring some concern for mixed 
precipitation again.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1236 PM CDT Sun Apr 7 2019

At TAF issuance time, a batch of MVFR CIGS continued to impact 
the TOP terminals. Further scattering and lifting to VFR
conditions is expected by 20Z. A weak front is moving through 
northeast KS, which will cause winds to veer to a northwesterly 
direction early this afternoon. Gusts of 20-25 kts are possible.
Some conditions tonight look favorable for radiational fog
development, however, confidence is not currently high enough to 
include in TAFS. Will monitor for possible inclusion in the next 
TAF period. 

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Hennecke
LONG TERM...65
AVIATION...Teefey