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Area Forecast Discussion (AFD)

Issued by Topeka, KS (TOP)

                            
000
FXUS63 KTOP 152301
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
601 PM CDT Mon Jul 15 2019

...AVIATION UPDATE...

.SHORT TERM...(This evening through Tuesday)
Issued at 334 PM CDT Mon Jul 15 2019

As of 20Z Monday afternoon the remnants of Hurricane Barry continue 
to progress northward through the MS River Valley. At this hour the 
center of the midlevel low was across northwest AR. An expansive 
stratocumulus field has developed across eastern KS as low-level 
moisture streams northwestward on the northern periphery of the 
midlevel low. A stout EML above 850 mb should preclude any 
shower/storm development this afternoon and early evening. In 
addition, the increased cloud cover has tempered temperatures a bit 
with highs ranging from the low 90s in the west and low to mid 80s 
across far eastern KS. A quiet night is expected area-wide with 
cloud cover rotating across eastern KS as the midlevel slowly ejects 
northward. Overnight lows will reach the upper 60s tonight. 

The warming trend ensues tomorrow as the remnants of Barry pushing 
eastward while the midlevel ridge expands across the central US. An 
attendant 850 mb thermal ridge will overspread the the Central 
Plains with 850 mb temperatures 21-25 C tomorrow afternoon -- 
translating to surface temperatures in the low to middle 90s. 
Factoring in dew points in the upper 60s to near 70 will result in 
heat indices in the 100 to 105 range, especially across central and 
north central KS.

.LONG TERM...(Tuesday night through Monday)
Issued at 334 PM CDT Mon Jul 15 2019

The heat will further build Wednesday through the remainder of the 
week into the weekend as the aforementioned thermal ridge 
overspreads the area. Associated 850 mb temperatures are expected to 
range from +24 to +29 C, translating to surface temperatures in the 
mid 90s to low 100s. With little change in low-level moisture, 
confidence has increase for multiple days of excessive heat. Heat 
indices are likely to range from 105 to 110 each afternoon Wednesday 
through Saturday, and possibly Sunday. As a result have issued an 
Excessive Heat Watch beginning at 1 PM Wednesday through 7 PM 
Saturday. There is a very slight chance for a shower/storm across 
far northern KS Wednesday afternoon as a weak midlevel perturbation 
rounds the ridge across NE.

The persistent midlevel ridge looks to break down by late weekend 
into next week as a trough ejects across the Northern Plains, 
shunting a surface cool front through the area. GFS/ECMWF guidance 
suggests the most likely timeframe of the frontal passage would be 
late Sunday into Monday. This frontal passage could also bring the 
potential for showers and storms. 

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday) 
Issued at 601 PM CDT Mon Jul 15 2019

Models show some low level moisture from the remnants of Barry
remaining over eastern KS through the night. With the boundary
layer decoupling and RAP forecast soundings showing some fog
potential, will include a tempo for MVFR VSBY. There could also be
some stratocu persist through Tuesday morning. At this point
models keep RH values more in line with scattered clouds than one
would expect with a CIG. So will just keep a mention of scattered
clouds below 3 KFT. The last couple runs of the HRRR have
suggested convection from NEB may make a run at northern KS.
Unless a strong cold pool develops and drives south, this seems
unlikely with forecast soundings showing substantial inhibition
with not much moisture advection into north central KS. Something
to keep an eye on. 

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Watch from Wednesday afternoon through Saturday 
evening for KSZ008>012-020>024-026-034>040-054>056-058-059.

&&

$$

SHORT TERM...Baerg
LONG TERM...Baerg 
AVIATION...Wolters