FXUS63 KTOP 192337

Area Forecast Discussion
National Weather Service Topeka KS
637 PM CDT Wed Jun 19 2019

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Thursday)
Issued at 338 PM CDT Wed Jun 19 2019

19Z water vapor imagery showed an area of low pressure located over
extreme northeastern MO/southeastern IA, moving northeast. An upper
level trough was evident from central SD extending southward toward
the TX panhandle. Scattered showers and isolated storms that
developed over northeast KS during the afternoon in the wake of the
departing low pressure system are expected to dissipate during the
late evening/early overnight hours as the surface low advances into
the Great Lakes region, and upper trough moves over and to the east
of the area. Skies will clear a bit tonight and winds will become
very light. Following recent rainfall, the ground in many
locations is still damp due to the lack of sunshine and cooler
temperatures today. All considerations combined, a few locations
could see some patchy light fog by early Thursday morning,
however, fog should not be widespread.

The region will be in between systems Thursday. Afternoon
temperatures will be noticeably warmer as low level WAA occurs
throughout the day. 850mb temps are expected to reach +20/22C and
700mb temps should warm to near +12C. With PBL mixing, surface temps
will warm into the mid to upper 80`s in east-central KS and could
reach 90 degrees in central portions of the state. Instability will
increase dramatically throughout the day but the warmer air in the
low levels should help keep much of the area capped. As such, most
of the day tomorrow is expected to stay dry, however, we cannot
completely rule out a few thunderstorms late in the day, especially
in far northeastern KS along the edge of the capped area. If storms
are able to get going they could quickly reach severe limits given
abundant instability values and bulk shear values around 35 kts. All
modes of severe weather will be possible.

.LONG TERM...(Thursday night through Wednesday)
Issued at 338 PM CDT Wed Jun 19 2019

Mid-level flow late this week will be characterized by rising
heights and backing winds as short-wave ridge builds in ahead of
Rockies trough.  Despite warming mid-level temps, will still have
chances for thunderstorms, a few of which could reach severe levels.

Perhaps the best chance at organized thunderstorm activity prior to
arrival of Rockies trough would be Thursday night into early Friday.
Not clear at this point whether convection would initiate closer to
home along a very weak frontal boundary progged to be located in
north-central KS, or whether it may come in the form of more
organized activity that initiates much further west. Either way,
plentiful instability available and shear appears adequate to allow
for some conditional severe activity.

Other than maybe some lingering activity Friday morning, bulk of
Friday looks relatively quiet (and summer-like) as we wait for
Rockies trough to arrive.  Caveat to that is very unstable airmass
that will be present.  Decent cap should be in place late Friday
which is unlikely to be broken, but not out of question enough low-
level mass convergence could take place along weak boundary(ies) to
generate an isolated severe storm or two.

Models starting to come in to better agreement with regards to
evolution of system for this weekend.  Prefer GFS more western
placement of surface features.  Summer-like conditional instability
will be present again Saturday, although strength of mid-level winds
may be a limiting factor for a more active severe wx day.  Flooding
may end up being most significant risk.

As trough moves eastward on Sunday, mid-level winds would be more
supportive of active severe wx day, although positioning of surface
boundary will be a key factor.  GFS suggests it may be east of area
by storm initation time.  If not, could end up with a busier day,
but suspect best chance for active wx will be Saturday night.

Early next week looking relatively dry as trough clears area and
weak mid-level zonal flow sets in.


.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 632 PM CDT Wed Jun 19 2019

VFR prevails at KTOP/KFOE/KMHK through forecast period. VCSH are
expected to clear KTOP/KFOE before 02Z with forecast soundings
showing increasing confidence for the stratus to linger through
the overnight period. This should deter the shallow fog potential
models were trying to develop aft 10Z just east of KTOP. Will
need to monitor as clouds are expected to clear out near this
time. Southerly winds increase above 10 kts sustained aft 18Z
with gusts in upwards of 25 kts in the afternoon.




LONG TERM...Manion

NWS TOP Office Area Forecast Discussion