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FXUS63 KTOP 140818

Area Forecast Discussion
National Weather Service Topeka KS
318 AM CDT Mon Oct 14 2019

.SHORT TERM...(Today and tonight)
Issued at 305 AM CDT Mon Oct 14 2019

An  upper level trough across west central Canada will dig southeast 
into the northern high Plains late this afternoon. A low amplitude 
upper level trough across southern CA will begin to shear out as it 
moves east into the southwestern US. Nearly zonal flow across the 
central Rockies will cause a lee surface trough across eastern 
CO/western KS to deepen. The deepening surface trough across western 
KS will cause the surface pressure gradient to increase across 
eastern KS. South-southeast winds will increase to 15 to 20 MPH with 
some gusts up to 30 MPH during the afternoon hours. Deeper mixing 
and WAA will help to warm high temperatures into the lower to mid 

Tonight the H5 trough cross the northern high Plains will dig east-
southeast into the upper Midwest late Tonight. Low-level CAA across 
the northern and central Plains will cause a surface cold front to 
move southeast across the CWA. Late Tonight southwesterly winds 
ahead of the front may bring sufficient low-level residual gulf 
moisture northeastward into portions of east central KS, generally 
along and southeast of I-35. The combination of surface convergence 
ahead of the surface front and ascent due to DCVA ahead of the 
digging H5 trough may be sufficient for scattered showers and 
isolated thunderstorms to develop. Even with the passage of the 
surface front the elevated showers and isolated storms may 
continue across the far southeast counties through the mid morning
hours of Tuesday. Winds will shift and become northwesterly at 15
to 20 MPH with some higher gusts after FROPA. 

.LONG TERM...(Tuesday through Sunday)
Issued at 305 AM CDT Mon Oct 14 2019

Tuesday through Wednesday night, low-level CAA with northwest winds 
of 15 to 20 MPH with higher gusts will only allow highs to reach the 
upper 50s north to mid 60s south. A surface ridge of high pressure 
will build southeast across the central and southern plains and be 
centered across eastern KS Wednesday afternoon. Highs Wednesday 
will only reach the mid to upper 50s but at least the northwest 
winds will diminish through the day. Tuesday night lows will get 
close to freezing across north central and northeast KS with mid 
to upper 30s across east central KS.

Thursday through Saturday, an upper level trough will move onshore 
across the western US and move east into the Plains late Friday into 
Friday night. There may be enough residual gulf moisture return 
across eastern KS, along with ascent ahead of the H5 trough and 
convergence along a weak pacific front, that will move east 
across the CWA Friday night, for scattered showers and a few 
thunderstorms to develop. The H5 trough and weak Pacific cold 
front will move east of the area, ending the chance for 
rainshowers by Saturday afternoon. A more amplified through will 
move into the western US on Saturday. Southerly winds ahead of a 
deepening lee trough will help to warm high temperatures into the 
upper 60s to lower 70s on Thursday, with lower to mid 70s on 
Friday. Saturday highs may be slightly cooler with upper 60s to 
lower 70s behind the weak surface FROPA.

Saturday night through Monday, the upper level trough across the 
western US will amplify as if digs southeast across the central 
Rockies, then shifts east across the Plains Sunday night into Monday 
morning. The strong southwesterly mid level flow across the central 
Rockies combined with ascent ahead of the H5 trough will amplify a 
lee cyclone across northeast CO Saturday night. A strong LLJ will 
develop across the southern and central Plains and begin to 
transport rich gulf moisture northward across KS into NE. The 
resulting isentropic lift may provide enough ascent for elevated 
showers and thunderstorms to develop towards the early morning
hours of Sunday. 

Sunday the surface cyclone will track northeast 
into southeast SD by late afternoon and a surface trough/cold 
front will shift east across western KS into central KS by 00Z 
MON. The vertical wind shear will increase across eastern KS 
through the afternoon hours as a 50 to 60 KT H5 jet max lifts 
northeast ahead of the upper trough across much of KS. Southerly 850mb
winds will increase to near 50 KTS and surface winds will be 
backed. Given the pattern, the mid level lapse rates will be 
steep with deep moisture in place thus the instability should be
moderately high. Thunderstorms that develop along the Pacific 
cold front/dryline may start out as scattered supercells across 
central KS then congeal into a squall line as the Q-G forcing 
increases through the afternoon hours. If the 00Z ECMWF continues 
to converge on this model solution then there will be a chance of 
severe thunderstorms across the CWA Sunday afternoon into Sunday 
night. Of course the ECMWF model solution could change over the 
next few days which may diminish the chance for severe 
thunderstorms. A negative factor that may reduce the chances for 
severe thunderstorms is if the morning convection continues into 
the afternoon and the atmosphere is worked over before the main H5
trough shifts east across the Plains. Then the instability may be
reduced but then there may be potential flooding hazard Sunday 
into Monday.

Monday, the stronger ascent will shift east of the Plains along with 
a surface cold front. There may be lingering showers into the 
afternoon hours across the CWA and High temperatures will cool into 
the 60s.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1120 PM CDT Sun Oct 13 2019

VFR wind forecast at KTOP/KFOE/KMHK as calm winds pick up between
10 and 15 kts sustained aft 16Z. Gusts to around 24 kts are likely
in the late afternoon as the sfc pressure gradient tightens in
association with a deepening sfc trough. A weak passing wave
tomorrow evening will increase the likelihood of LLWS at 
KTOP/KFOE aft 02Z accompanied by a mid level cloud deck closer to 
06Z. Winds aloft were not as strong at KMHK so left out LLWS 
mention for tomorrow evening.




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