Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

000 
FXUS63 KTOP 240501
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
1201 AM CDT Sat Aug 24 2019

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Saturday)
Issued at 349 PM CDT Fri Aug 23 2019

Slight chances for showers and storms will be the norm through the 
first half of the weekend.  

Currently, a very weak ill-defined mid level shortwave/convectively 
induced vort max continues to work through western into central 
Kansas helping to give support to a small cluster of storms over 
central Kansas which has been back building into south central and 
southwestern portions of Kansas within a more unstable airmass. 
Little flow in the pattern remains over the area with tropical air 
residing over the southern portions of the CONUS and the main 
Westerly flow displaced well to the north of the area over the 
extreme northern tier of the CONUS.  A positively tilted trough 
extends back into the Great Lakes region while a weak cut-off low is 
over the northern Rockies.  

Convection over the foothills of the Rockies is anticipated to 
continue to develop and organize into late over night which will 
have potential implications for the Saturday morning forecast for 
mainly north central Kansas.  Current afternoon showers and storms 
should diminish as the boundary layer stabilizes after sunset over 
north central areas.  Steepening low level lapse rates may cause 
some gusty outflow winds with these storms but severe weather is not 
anticipated.  As for the previously mentioned convection over 
eastern CO, an MCS should be allowed to be supported into the 
overnight as storms congeal and advance east and make a run for the 
area by early morning.  The LLJ overnight remains focused mainly out 
over western Kansas, so storms should be allowed to weaken as they 
move into north central areas.  Expecting the result will be remnant 
showers and storms into Saturday morning across western portions of 
the area.  Can't rule out spotty afternoon convection with daytime 
heating.  High temperatures top out around 80 degrees with cloud 
cover in place much of the day beginning with low stratus due to the 
moist low levels. 

.LONG TERM...(Saturday night through Friday)
Issued at 349 PM CDT Fri Aug 23 2019

The mid to long range forecast will likely see periodic chances for 
showers and storms with possibly some severe potential on Monday 
afternoon associated with a fairly strong cold front for this time 
of year.  

Saturday night into Sunday morning will see another complex of 
storms develop over northwestern KS into south central NE before 
advancing southeast overnight mainly bringing a heavy rain threat to 
western portions of the area.  Exact track of most intense storms 
may just be west of the area though, so flash flood concerns right 
now would likely also be focused over central in western portions of 
Kansas.  The LLJ does appear to veer and weaken as storms move 
through the area on Sunday morning as well again with focus for the 
strongest convergence over western areas should storms with heavy 
rainfall move into the area.  

Afternoon storms move through the area, upper pattern transitions to 
a more northwest flow component into Monday with a surface boundary 
bisecting the area from southwest to northeast.  An area of low 
pressure deepens over the panhandle of TX.  Strong instability and 
sufficient shear ahead of the boundary could give rise to afternoon 
storms during this Monday afternoon time frame and can't rule out 
severe weather with mainly a wind and hail threat along with heavy 
rainfall.  Winds appear to be more southwesterly along the boundary 
so a tornado threat would appear low at this time.  

Main change with the long term forecast was to reduce POPs during 
the Wednesday time frame as high pressure sets up over the area and 
an overall dry airmass should set up across the area.  Dewpoints 
could be the best part of this setup as they may fall into the
50s. 

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1154 PM CDT Fri Aug 23 2019

VFR conditions this evening should deteriorate as MVFR to IFR
stratus builds in after 08-10Z. These ceilings should only slowly
improve during the day on Saturday, possibly reaching low VFR in 
some locations by the afternoon. Occasional showers and 
thunderstorms are possible throughout the period, but confidence 
in timing was not high enough to go beyond VCSH in the TAFs.

&&

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

$$

National Weather Service Glossary of Abbreviations