Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 231723
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
1223 PM CDT Sun Apr 23 2017

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 301 AM CDT Sun Apr 23 2017

Early this morning a mid-level ridge was building into Kansas with
the center of the surface high pressure situated over western and
central KS.  The combination of light winds and clear skies will
result in temperatures before sunrise plunging into mid/upper 30s.
As a result, some low-lying areas particularly near river valleys
may see some patchy frost development by sunrise.

Late morning into early this afternoon, models show the surface high
pressure beginning to shift eastward over the area, causing surface
winds to back to the south. A decent pressure gradient will set up
over western and central KS as an area of low pressure quickly
advances into the High Plains region.  As a result, these southerly
winds over central KS may become breezy this afternoon with gusts of
20-25mph. These southerly winds will support decent WAA with
afternoon temperatures quickly rising into the low 70s for much of
the CWA.  By tonight, the area of surface low pressure will continue
to advance eastward into western and central KS, resulting in a
tightening pressure developing over the CWA.  As a result, have
southerly winds increasing overnight with gusts of 25-30 mph
expected by Monday morning across north central KS.  Despite mostly
clear skies, these breezy southerly winds will keep overnight
temperatures a bit warmer with lows in the mid/upper 40s.

.LONG TERM...(Monday through Saturday)
Issued at 301 AM CDT Sun Apr 23 2017

Monday still on track to be warm and breezy across the area with
high temperatures rising to the middle/upper 70s. As a surface low
moves eastward out of southeast Colorado overnight into early
Tuesday, there is a slight chance for some showers and possibly
isolated thunder as the front and isentropic lift shift northward
over the area. Another northern stream wave moves quickly
eastward just to our north during the day on Tuesday, and ushers
a front southeast across eastern Kansas by late afternoon. GFS
advects more instability into the eastern counties ahead of this
front, while the EC shunts it farther to the south and east as
the trof moves overhead. Far southeast counties are outlined for a
marginal risk for severe storms given potential amount of
instability, shear and lapse rates, with better ingredients just
to our southeast. Depending on speed of the front, this area could
shift north or south with time. Chance for showers continues into
Wednesday as rain wraps behind the low. Bit of a break forecast
for Wednesday night as surface ridge moves overhead. Highs Tuesday
in the 60s to low 70s cool down into the 50s under the cooler high
pressure from the north.

At this time, weak lead shortwave brings more rain chances for
Thursday and Thursday night, with the GFS quicker to return
instability back over eastern Kansas on Friday. Added some thunder
to the eastern counties for this possibility. Both EC/GFS have a
large scale upper trof over the high plains and would bring ample
ingredients for strong storms over the state on Saturday,
possibly overnight Friday night into Saturday if storms develop as
the warm front lifts back northward. However model runs have
experienced notable timing and strength differences over the past
few days, so will just need to monitor and see how this trof
evolves.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1219 PM CDT Sun Apr 23 2017

VFR prevails through period. Main concern is llws from a deepening
low pressure area to the west. Timing of the strong ll winds from
west to east begins at KMHK in the 06 to 08Z time frame. TOP and
FOE are closer to 10Z. Forecast soundings show the speed shear
beginning in the 300-500 ft layer, continuing through the top of
the boundary layer. Aft 14Z, sfc winds increase and become gusty
through the afternoon.

&&


.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Hennecke
LONG TERM...67
AVIATION...Prieto



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