Preview of NWS' New Version of Forecast
This preview is not operational and should not be used for support decisions.

Area Forecast Discussion (AFD)

Issued by Topeka, KS (TOP)

FXUS63 KTOP 202331

Area Forecast Discussion
National Weather Service Topeka KS
631 PM CDT Sat Apr 20 2019

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Sunday)
Issued at 245 PM CDT Sat Apr 20 2019

Mostly clear skies this afternoon and the first half of the evening 
as upper ridge gradually moves eastward and the upper trough 
advances towards western Kansas by Sunday morning. With highs 
climbing into the lower 80s this afternoon and cirrus deck 
increasing west to east overnight, overnight lows are forecast to be 
much warmer in the low to middle 50s. As the sfc pressure gradient 
tightens around the developing low Sunday morning, southerly winds 
become strong from morning onward with sustained speeds between 15 
and 25 mph with gusts up to 40 mph. Moisture increases ahead of the 
sfc low and attendant cold front across much of central and eastern 
Kansas as most guidance peaks in the upper 50s to near 60 degrees by 
late afternoon. Ample mixing of warm air aloft combined with decent 
warm advection to the south lead to increasing highs Sunday a few 
degrees, especially in north central areas with lesser insulation 
from the high clouds. Overall readings range from the low 80s east 
central Kansas to the middle 80s central Kansas.

.LONG TERM...(Sunday night through Saturday)
Issued at 245 PM CDT Sat Apr 20 2019

A stout capping inversion across the CWA should preclude any 
thunderstorm development until early evening, centered closer to the 
frontal boundary stretched from western Kansas through south central 
Nebraska. Forecast soundings towards far north central Kansas and 
southern Nebraska indicate a weakening mid level inversion layer and 
steepening mid level lapse rates from 23Z-01Z. Ample CAPE is 
supportive of convection with some uncertainties remaining on the 
strength of the cap and therefore storm coverage, indicated by all 
guidance. If storms are able to develop, it will likely form west of 
the CWA and track into north central Kansas after 7 PM. Deep layer 
shear remains on the marginal end from 25 to 30 kts with some 
question as to how long cells will be able to sustain themselves. 
Regardless, isolated storms that are able to form given the 
environment could become strong or severe with large hail and 
damaging winds the main hazards. As the cold front advances 
southeast overnight, elevated storms are expected to weaken as they 
push eastward over the northern half of the CWA.

The frontal boundary slows across the CWA on Monday with the cooler 
air entering north central Kansas during the afternoon. Highs 
therefore range from the upper 60s in north central Kansas, to the 
upper 70s in east central Kansas reaching the middle 70s for most of 
the area on Monday with mostly cloudy skies and gusty north winds. 
Elevated thunderstorms may redevelop during the late afternoon over 
east central Kansas. With around 1500 J/KG of MUCAPE and 35 kts of 
effective bulk shear, a few marginally severe storms may be possible 
once again for these areas. 

As the front stalls Monday evening, it becomes the focus for decent 
lift as a lead upper wave lifts out into the central plains. Models 
are pretty wide ranging between extent of moisture and location of 
the front to correlate with more widespread coverage of showers and 
thunderstorms through Tuesday. Current thinking is the optimal 
chances for precip are generally south of Interstate 70 through 
Tuesday as the upper low gradually meanders across the southern 
plains through mid week. Mostly sunny skies return Wednesday onward 
as temps quickly warm above normal values in the upper 70s for highs 
and lows in the lower 50s.


.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 631 PM CDT Sat Apr 20 2019

Low level wind shear is forecast to develop in the 04Z to 06Z time
frame at the Terminals and continue through 13Z. WInds generally
south around 10 kts will increase to near 15 kts with gusts to
around 25 kts by 15Z.




LONG TERM...Prieto