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000
FXUS63 KTOP 181743
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
1243 PM CDT Sun Jun 18 2017

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 252 AM CDT Sun Jun 18 2017

07Z water vapor imagery shows a shortwave moving through the upper
Midwest with upper ridging over the southwest. At the surface, a
frontal boundary has pushed into northern OK and southwestern MO
with a broad area of elevated showers and thunderstorms across the
state stretching back to western KS. This precip behind the front
appears to be a combination of frontogenesis and isentropic upglide.

For this morning, the RAP and NAM indicate that while the
frontogenesis should diminish, there may still be enough isentropic
upglide for scattered showers and storms through at least mid
morning. This idea is supported by the HRRR/NMM showing scattered
precip over east central KS through about 14 or 15Z. Once the shower
activity pushes south, the forecast is for dry weather for the rest
of today and tonight. Models are in good agreement for surface
ridging to remain over the forecast area with northwest flow aloft.
While there may be some weak perturbations within the flow aloft,
dryer and cooler air in low levels with the surface ridge will
stabilize the atmosphere limiting precip chances. The cooler air
advecting into the area with the surface ridge is expected to keep
afternoon highs in the lower 80s for today. Lows tonight are
forecast to be in the mid and upper 50s. Some mid clouds moving from
west to east tonight may keep lows from cooling off any more than
that.

.LONG TERM...(Monday through Saturday)
Issued at 252 AM CDT Sun Jun 18 2017

By Monday, surface high pressure will be centered over the region
with northwesterly flow aloft as the deep mid-level trough
progresses into the eastern U.S.  This pattern will support dry and
more seasonal conditions for Monday with high temperatures in the
mid 80s.  The surface high pressure will shift east of the CWA
Tuesday into Wednesday with the mid-level flow transitioning to a
more zonal flow as the mid-level trough lifts into the New England
region.  Models show this zonal mid-level flow remaining in place
over the central U.S. through late week before a mid-level trough
develops in the flow and dives into the Northern and Central Plains
Friday into Saturday.  While the zonal flow is in place mid-week,
models show the potential for scattered shower and thunderstorm
chances as a few weak embedded shortwaves may develop and skim
across the CWA during the Tuesday night through Thursday night
period.  At this time, the strongest shortwave looks to develop and
track over the area Thursday night into Friday morning, in which it
may push a cold front into north central KS.  As the mid-level
trough dives into the central U.S. by late week, it will aid in
pushing this cold front southward across the CWA Friday into Friday
night with thunderstorms likely developing along and behind the
front. This system may provide the best potential for some strong to
severe thunderstorms.  High pressure will begin to nose into KS
behind this exiting system, with mostly dry and cooler conditions
expected for the start of next weekend.

As for temperatures, expect high temperatures to rise back into the
90s by Tuesday as the eastward-shifting high pressure will support
southerly winds into the region.  Temperatures will continue to
moderate through mid-week with the warmest conditions expected Wed.
and Thu. with highs in the low/mid 90s and heat index values rising
back into the upper 90s to low 100s.  Seasonal conditions will
return behind the frontal passage with Saturday high temperatures
looking to be in the 80s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1239 PM CDT Sun Jun 18 2017

VFR conditions are expected through the TAF period with
northwesterly winds of 10 to 15 kts decreasing below 10 kts
after sunset. A mid level cloud deck may bring some very light
showers/virga tomorrow morning, possibly transitioning into
widely scattered showers in the afternoon.

&&

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

$$

SHORT TERM...Wolters
LONG TERM...Hennecke
AVIATION...Skow