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Area Forecast Discussion (AFD)

Issued by Topeka, KS (TOP)

FXUS63 KTOP 150752

Area Forecast Discussion
National Weather Service Topeka KS
252 AM CDT Sun Sep 15 2019

.SHORT TERM...(Today and tonight)
Issued at 245 AM CDT Sun Sep 15 2019

Several mid-level, weak vorticity maxima are observed shifting 
eastward through the Midwest region this morning. Elevated showers 
and storms as a result have developed over portions of northwest 
Missouri and our CWA within the past hour. Despite the low signal 
from short term models, IR satellite imagery is depicting cooling 
cloud tops from Jackson through Morris counties. Isolated showers 
and thunderstorms should continue to develop through sunrise before 
dissipating as the low level jet weakens. Storms are not expected to 
be severe with much of the speed shear associated with the LLJ in 
the lower levels. Main hazards are isolated strong wind gusts and 
lightning. Midlevel clouds clear out by early afternoon, leading to 
another warm and humid afternoon. Sided closer to Consraw guidance 
on temps, especially given that we are starting out warmer with lows 
and strong boundary layer mixing up to 850 mb should lend to warmer 
temps compared to Saturday. Overall forecast highs range in the low 
to mid 90s. 

Upper ridge expands northward this evening, giving way to clear 
skies overnight. Meanwhile, northeast Kansas remains wedged between 
an area of sfc high pressure to the southeast and the lee trough 
towards the western high plains. South winds from east to west 
increase from calm up to 10 mph in north central areas. Monday 
morning lows are generally around 70 degrees.

.LONG TERM...(Monday through Saturday)
Issued at 245 AM CDT Sun Sep 15 2019

Dry and warm weather persists through Wednesday as the upper ridge 
amplifies in response to the deepening upper trough over the western 
CONUS. Current pops in the forecast remain low beginning late 
Tuesday onward, given the high variability in guidance. All guidance 
with the exception of the ECMWF signal the leading upper trough to 
lift into the northern plains Tuesday evening, developing a line of 
storms along a cold that sweeps across northern Kansas on Wednesday 
morning. The ECMWF brings the weak front through northern Kansas by 
late afternoon Wednesday with the focus for redevelopment being near 
the boundary. With the vicinity boundary and several mid level waves 
lifting out of the main system Thursday through Saturday, it seemed 
reasonable to keep the low chance pops in each period, especially 
given the differing solutions. For this forecast, it appears that 
Saturday afternoon and evening is depicting a similar signal in the 
main upper low occluding into far northern Dakotas, sending a 
stronger cold front through the region. Higher pops were mentioned 
for this period. A cooler, more seasonable airmass returns to the 
area by Sunday. While a few stronger storms are possible throughout 
the week, very weak effective bulk shear will preclude a widespread 
severe threat.


.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1140 PM CDT Sat Sep 14 2019

Low level wind shear will continue through 14Z at the terminals as
the low level jet remains near 40 kts near 1200 ft to 1300 ft
before weakening after sunrise. Winds forecast to range near 
12 kts with gusts to near 20 kts through 21Z before decreasing to
less than 10 kts by 23Z. VFR conditions are expected as convection
looks to remain isolated and north of the terminals.