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Area Forecast Discussion (AFD)

Issued by Topeka, KS (TOP)

                            
000
FXUS63 KTOP 200748
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
248 AM CDT Sat Jul 20 2019

.SHORT TERM...(Today and tonight)
Issued at 247 AM CDT Sat Jul 20 2019

For today, the broad, expansive mid-level ridge will remain anchored 
across the southern half of the CONUS.  At the surface, the CWA 
remains wedged between high pressure over the southeastern U.S. and 
an area of low pressure over the High Plains region, with a decent 
pressure gradient resulting in breezy southerly winds gusting 
upwards of 20-25 mph through this afternoon.  These gusty winds will 
support continued warm, moist-air advection with dewpoints looking 
to reach into the low/mid 70s once again.  

The mid-level and surface patterns will start to break down during 
the weekend as a mid-level trough over Canada slides southward into 
the Northern Plains, which will help to push a surface cold front 
southward into the area.  However, models have been trending a 
little bit slower with the advancement of the front into the area, 
with the better forcing lagging further behind.  As a result, do not 
anticipate mid/high clouds moving into northern KS until this 
evening, so have a dry forecast in place through the daytime hours. 
Additionally, with the slower advancement of cloud cover, expect WAA 
from the persistent southerly flow to result in another very hot and 
humid day.  850mb temperatures look to range from 25C to 30C this 
afternoon, so anticipate high temperatures today to be very similar 
to yesterday with readings soaring into the upper 90s to low 100s 
with heat index values ranging from 107 to 115 degrees.  As a 
result, the Excessive Heat Warning remains in effect for the entire 
outlook area through this afternoon.  

As the cold front slowly tracks southward into north central to 
northeast KS this evening, models show some of the better forcing 
finally sliding into the area by the late evening and overnight 
hours.  As a result, have slowed the spread of PoPs across the CWA 
tonight and have PoPs predominantly focused north of I-70 and 
especially near the KS/NE border.  Also, with the better forcing 
staying along and north of the KS/NE border and effective bulk shear 
looking somewhat weak, anticipate the potential for any stronger 
storms to remain north of the CWA for tonight. 

.LONG TERM...(Sunday through Friday)
Issued at 247 AM CDT Sat Jul 20 2019

Better chances for scattered showers and storms are expected Sunday 
into Sunday evening as the front progresses through the area. 
However, there is still some model variability with the exact timing 
of the frontal passage through the CWA, which will have an impact on 
temperatures and how expansive the area of destabilization ahead of 
the boundary will be.  In general, though, the combination of 
destabilization across east central KS ahead of the frontal passage, 
effective bulk shear values getting closer to around 30kts, and 
better forcing in place with the advancing front will result in the 
potential for some strong to severe thunderstorms to develop Sunday 
afternoon/evening, with gusty winds, small hail, and locally heavy 
rainfall be the primary hazards.  Models have been trending toward 
having the higher QPF amounts being focused across northeast and 
east central KS and further northeast from there into northwest MO 
and southern IA.  However, there is still model variability with 
regards to just how much QPF can be expected as the GFS continues to 
be notably higher with QPF compared to other models.  As the cold 
front tracks east of the CWA Sunday night, post-frontal showers and 
storms should gradually exit the area overnight into early Monday 
morning.  

Dry conditions are expected through this upcoming week as an 
expansive area of surface high pressure builds into the central 
CONUS behind the exiting low pressure system, with a deep mid-level 
ridge building across the western U.S.  Temperatures through the 
first half of next week will be cooler than the seasonal normals 
with highs in the low/mid 80s and lows in the upper 50s/low 60s.  As 
the surface high shifts further east of the area by late week, the 
shift back to southerly winds will result in a gradual moderating 
trend with highs into the upper 80s by Thursday and Friday.  


&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1142 PM CDT Fri Jul 19 2019

The low-level jet will remain in to 40-45 KT range at about 1500 
feet above the surface through the night. Surface winds should 
remain under 11l KTS which cause low-level wind shear to remain 
at or over 30 KTS across the terminals through 13Z SAT. 
Otherwise, expect VFR conditions.


&&

.TOP WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning until 8 PM CDT this evening for 
KSZ008>012-020>024-026-034>040-054>056-058-059.

&&

$$

SHORT TERM...Hennecke
LONG TERM...Hennecke
AVIATION...Gargan