Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 171028
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
528 AM CDT Tue Sep 17 2019

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 311 AM CDT Tue Sep 17 2019

Upper ridge axis this morning continues to edge eastward into the
Midwest region. Mid level moisture return continues today as several
embedded perturbations are noted lifting towards the western high
plains ahead of the mid level trough axis in Oregon. Despite the
decent low level mixing and gusty south winds this afternoon, cirrus
clouds should once again temper highs a few degrees to the low 90s.
A secondary upper trough is progged to cross the Pacific Northwest
coast this evening, shifting the first upper wave into the northern
plains. Upper level forcing upstream of the wave focuses in vicinity
of a front stretching across NE, with a cluster of thunderstorms
progged to develop and shift through Iowa after midnight tonight.
Moisture profiles from most guidance is more dry compared to
previous evenings with weaker lapse rates over east central and
north central areas. It remains possible that the storm cluster
could clip far northeast Kansas so I kept the chance pops in aft 06Z.
Weak 0-6 km bulk shear does not support severe updrafts.

.LONG TERM...(Wednesday through Monday)
Issued at 311 AM CDT Tue Sep 17 2019

Guidance in the extended period is becoming more consistent with
the sfc front setting up from southwest KS through northeast NE. A
weak capping inversion may allow for scattered convection to
develop by late afternoon Wednesday. Coverage is of question with
the optimal upper forcing in Iowa, but have increased pops for the
late afternoon. Additional storms are again possible overnight as
the LLJ overruns the front in NE, perhaps reaching as far south as
northern Kansas. Thursday and Friday should be mostly dry with
increasing cloud cover as the main upper trough arrives into the
northern plains. The latest GFS and ECMWF continue to vary from
here on out as the front shifts southward into Kansas on Saturday.
The GFS is consistent with the faster solution on frontal timing
compared to the ECMWF that swings the front through the CWA early
Sunday morning. Thunderstorms now appear likely overnight,
especially over east central Kansas where both the ECMWF and GFS
maximize qpf values to around 1 inch. The front is expected to
slow in southern KS by Sunday with the potential for occasional
thunderstorms through Tuesday, particularly south of Interstate
70. The drier airmass will finally relieve the area from the hot
and humid conditions Sunday with dewpoints around 60 degrees and
highs in the low 80s into early next week.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 521 AM CDT Tue Sep 17 2019

VFR prevails as south winds increase above 10 kts sustained
between 15Z and 17Z. Mid clouds increase west to east aft 06Z.
Any scattered TSRA that develops looks to remain north and east
of terminals between 06Z and 12Z.

&&


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

$$

SHORT TERM...22
LONG TERM...22
AVIATION...22


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