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Area Forecast Discussion (AFD)

Issued by Topeka, KS (TOP)

FXUS63 KTOP 191709

Area Forecast Discussion
National Weather Service Topeka KS
1209 PM CDT Tue Mar 19 2019


.SHORT TERM...(Today and tonight)
Issued at 335 AM CDT Tue Mar 19 2019

Today through Tonight, an upper level trough across the central high 
Plains this morning will dig southeast across eastern KS Tonight.
Ahead of the upper trough southwesterly winds at 850mb were 
transporting modified gulf moisture northeast across the CWA. The 
area of better isentropic lift was occurring north of I-70 where 
light rainfall has finally saturated the drier low-levels for 
rainfall to reach the surface. Through the morning hours the light
rain will expand northward as the stronger isentropic lift 
extends northward to the NE border. Most of north central and 
northeast KS will see periods of light rain through the morning 
and afternoon hours. An inverted surface trough will build 
northeast into east central KS during the early afternoon hours as
DCVA ahead of the digging H5 trough leads to lower surface 
pressures across south central KS. A bit of a warm sector will 
develop across east central KS this afternoon, with surface winds 
veering to the south ahead of the surface trough axis. High 
temperatures across east central KS will warm into the upper 50s 
to lower 60s and if the cloud cover can break up there could be 
some mid 60 degree readings. The surface warm front will only 
reach as far north as northern Shawnee county/southern Jackson 
County and points east. The remainder of the CWA will only see 
highs in the mid 40s to lower 50s. Surface winds across the 
western counties will become northerly with light rain developing 
northwest and west of the front as DCVA increases ahead of the 
advancing H5 trough and 850mb winds remain from the southwest, 
providing for weak isentropic ascent west of the front. As the 
surface front/trough shifts east across east central KS the band 
of post frontal light rain will move east across east central KS 
during the late afternoon and evening hours. As the upper trough 
axis digs southeast into north central and central KS the stronger
ascent will shift east of the CWA and 850mb winds will veer to 
the west and northwest across the CWA. The heavier band of post 
frontal showers will shift east of the CWA after 6Z WED. QPF will 
range from around 0.4" across northeast KS to 0.1-0.2" along and 
south of I-70.

.LONG TERM...(Wednesday through Monday)
Issued at 335 AM CDT Tue Mar 19 2019

Wednesday through Friday, the southern stream H5 trough across 
eastern KS Wednesday morning will dig east-southeast into the lower 
MS River Valley, while a northern stream H5 trough digs southeast 
out of central Canada into the Great Lakes States by 6Z THU. Both 
the northern stream and southern stream H5 troughs will phase 
together across the eastern US on Thursday. The central Plains 
will remain under northwesterly flow aloft with the stronger mid-
level flow shifting eastward into the MS River Valley Thursday 
night. An upper level ridge across the western US will move east 
towards the Plains late Thursday. A southern stream H5 trough 
will move onshore across central and southern CA by 18Z WED and 
then slowly shift east into the southwestern US by 00Z FRI. A 
broad surface ridge of high pressure will build southeast across 
eastern KS Wednesday night, then shift south-southeast across the 
lower MS River Vally by Friday. Highs Whitsunday and Thursday will
reach the mid to upper 50s. Increasing mid-level flow over the 
central Rockies will cause a lee surface trough to deepen across 
the central and southern Plains on Friday. Light and variable 
winds across the CWA Friday morning will become southeasterly 
through the day. Low-level warm advection will help high 
temperatures to reach the lower to mid 60s Friday afternoon. Gulf 
moisture will advect northward across northwest TX, into western 
KS through the day Friday, and the resulting isentropic lift and 
ascent ahead of the H5 trough lifting northeast across the 
southern and central high Plains will cause showers and 
thunderstorms to develop across western KS through the afternoon 
hours of Friday.

Friday night through Monday night, the H5 trough axis across the 
southern high Plains will lift northeast across KS on Saturday. 
Ahead of the upper trough low-level southerly winds will advect
modified gulf moisture northward and the resulting isentropic 
lift combined with DCVA ahead of the H5 trough axis will cause 
widespread showers and perhaps a few elevated thunderstorms but 
MUCAPEs looks to be under 400 J/kG, so we may not have enough 
instability for thunderstorms. The showers will last through the 
day but the heavier rain will shift east into MO during the 
afternoon hours of Saturday. A second upper level trough will move
onshore across northern CA and dig east-southeast across the 
Plains late Sunday afternoon. Rain chance will once again increase
Saturday night through the day Sunday. If there is enough 
instability there may be a few elevated thunderstorms late 
Saturday night into Sunday afternoon. The upper trough will 
amplify into a closed upper low across eastern KS, thus the light
rain will probably continue into Tuesday evening. Once the upper 
trough shifts east of the area Monday night, the rain should end 
by 6Z TUE across the eastern counties of the CWA. Highs Saturday 
through Monday will be in the 60s. 

Tuesday, Low-level CAA will cool high temperatures back into the mid 
to upper 50s. Skies will clear west to east across the CWA through 
the mid and late morning hours. North winds may be a bit gusty as
the pressure gradient tightens between a surface ridge across NE 
and western KS and a surface low over the mid MS River Valley.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1209 PM CDT Tue Mar 19 2019

There is pretty good consensus among the short term models for a
band of showers and possibly a thunderstorm to move through with
the FROPA this afternoon and evening. MVFR CIGS are expected to
overspread the area behind the front and remain over the terminals
until mid to late morning Wednesday. Timing of precip and CIG
changes based largely off the CAMs. 




LONG TERM...Gargan