Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

FXUS63 KTOP 211939

Area Forecast Discussion
National Weather Service Topeka KS
239 PM CDT Mon Oct 21 2019

.SHORT TERM...(This evening through Tuesday)
Issued at 230 PM CDT Mon Oct 21 2019

A deep upper low was located across northeast NE/northwest IA this 
afternoon, with an upper level trough axis extending southward 
across far eastern KS into east central TX. Wrap around moisture has 
caused stratus to develop across much of the CWA. The cloud cover 
has limited the deeper mixing of the PBL, and thus winds have 
remained just below advisory criteria across north central KS. There 
are some breaks in the overcast beginning to develop across north 
central KS, which may lead to deeper mixing and better momentum 
transfer to the surface for winds to increase to or just above 
advisory levels. Some gusts across the southwest counties of the CWA 
may approach 50 MPH through the remainder of the this afternoon. 
Therefore, I'll keep the wind advisory going through 7 PM.

Tonight, the stronger winds will gradually diminish through the 
evening hours. The winds will remain around 10 to 15 MPH through the 
night, thus given clear skies and lower dewpoints, temperatures will 
only drop into the upper 30s to lower 40s.

Tuesday the upper low will shift northeast into the Upper Great 
Lakes States as the upper trough axis moves east across the 
eastern US. the central and southern Plains will remain in 
northwesterly aloft. A broad ridge of surface high pressure will 
build southeast from the central high Plains into OK and eastern 
TX. Surface winds will veer more to the west as the center of the 
surface ridge passes well south of the CWA. Highs will warm 
slightly into the upper 50s to mid 60s.

.LONG TERM...(Tuesday night through Monday)
Issued at 230 PM CDT Mon Oct 21 2019

Tuesday night through Thursday night, an upper trough will dig 
southeast out of western Canada and across the central Rockies, then 
shear apart as it moves across the Plains. The southern section of 
the H5 trough will become a closed upper low across western TX and 
become cut off from the northern branch of the upper jet according 
the ECMWF and Canadian models. The GFS keeps the southern stream 
trough as an open wave. A cold front will move south across the CWA 
on Wednesday, as low-level CAA across the northern Plains 
develops as the northern branch of the H5 trough shifts east 
across the northern Plains into the upper midwest. Northwest of 
the front there may be enough weak isentropic lift along with 
larger scale ascent, from the DCVA ahead of the positive tilt H5 
trough axis, for light rain showers to develop Wednesday night 
into Thursday. The best rain chances will be across the southeast 
counties of the CWA. As the surface cold front pushes southward 
across central and eastern TX, the better area of isentropic lift 
and mid-level ascent will shift southeast of the CWA and the rain 
showers will end Thursday evening. Highs on Wednesday, ahead of 
the surface cold front will warm into the mid to upper 60s. As the
front passes southeast across north central and northeast KS 
Wednesday afternoon, temperatures may begin to fall back into the 
50s by the late afternoon hours. North winds, cloud cover and 
scattered rainshowers will only allow highs on Thursday to reach 
the upper 40s to lower 50s. Skies may clear late Thursday night, 
allowing overnight lows to drop into the upper 20s to lower 30s.

Friday through Friday night, the ECMWF and Canadian model solution
show the closed upper low over west TX only drifting east across 
west central TX through the day. The GFS solution shows a southern
stream upper trough moving east across central and eastern TX. 
The stronger ascent will remain well south of the CWA, so we 
should remain dry. Given more insolation, high temperatures will 
warm slightly into the upper 50s to lower 60s.

Saturday through Saturday night, The ECMWF and Canadian models lift 
the upper low northeast into OK and southern MO. The ECMWF is more 
amplified and shows an area of stronger ascent ahead of the H5 
trough moving across east central and northeast KS Saturday into 
Saturday night. If the ECMWF verifies, then there will be a 
chance for light rain Saturday into Saturday night. The Canadian 
is less amplified and tracks the upper low a bit farther south of 
the CWA, which would keep any precip across far southeast KS on 
Saturday. The GFS has an open southern stream H5 trough which is 
more progressive and shifts east across the southern US. If the 
GFS were to verify, then Saturday will remain dry and warmer with 
highs in the mid to upper 60s. All models show another upper 
trough digging into the western US. 

Sunday through Monday, the upper trough across the western US will 
move east across the Plains. The GFS and Canadian are more 
progressive than the ECMWF. The GFS moves the surface front across 
the CWA Sunday morning with the stronger ascent ahead of the H5 
trough remaining north and northeast of the CWA. While the ECMWF 
solution amplifies the upper trough across the southwestern US and 
does not bring the front southward across the CWA until Monday 
afternoon. Both model solutions show dry conditions for most of the 
area Sunday and Monday. Highs will be dependent on FROPA but expect 
60s on Sunday and may be a cool down on Monday with mid to upper 50s.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1233 PM CDT Mon Oct 21 2019

The Broken Stratus at 4000 to 5000 feet will continue through he 
afternoon hours. This may help to keep northwest winds to remain 
under 25 KTS with gusts under 40 KTS the remainder of this 
afternoon. The winds will gradually diminish through the evening 
hours. However, northwest winds above 1000 feet will continue to 
be in the 40 to 45 KT range through the early morning hours of 
Tuesday. Therefore, all terminals may experience low-level wind 
shear from 3Z TUE through 13Z TUE.


Wind Advisory until 7 PM CDT this evening for KSZ008-009-020>022-



National Weather Service Glossary of Abbreviations