Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 111744
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1244 PM CDT Fri Jul 11 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 321 AM CDT FRI JUL 11 2014

A very few isolated showers popping south of the forecast area, with
larger complex of showers and storms across Nebraska into Iowa at
this hour.  Temperatures remain in the middle 70s with south winds
across eastern Kansas.

For today, opted to keep a brief shot of showers or isolated TS out
of the far eastern counties, as most solutions keep precipitation at
bay. Can see isentropic lift generating clouds at this time, but
saturation surfaces around 305K race east quickly and don`t look to
generate convection until east of the area.  Highs should mix into
the middle 90s east to upper 90s west as 850mb temps of 22-24c shift
over the area.  Dewpoints are enough for heat indices in the upper
90s to near 100 for much of the forecast area.  Guidance for
overnight lows tonight were on the low side considering warm air and
weak mixing remain in the overnight hours, and have adjusted to lows
in the lower to middle 70s.

.LONG TERM...(Saturday through Thursday)
Issued at 321 AM CDT FRI JUL 11 2014

For tomorrow a weak shortwave tracking along the northern periphery
of the upper level ridge passes to our north over NE and IA. A
trailing cold front will then drop south into the forecast area
during the overnight hours. As the front moves through the area mid
level support looks to be limited as the main shortwave tracks into
the Great Lakes region at that point. The better instability appears
to be confined to areas along and near the KS/NE state line during
the late evening hours. Although shear is marginal at best therefore
do not expect much organized severe weather. Have kept the better
chances for thunderstorms north of interstate 70 as the instability
decreases further south and into the early morning hours.
Temperatures will warm again ahead of the front with heat indices
likely reaching the low 100s across the area. On Sunday the boundary
progress southward as well as the left over showers from the
overnight convection. Have kept a slight chance for precip along the
boundary as not certain if any redevelopment will take place during
the afternoon. High temperatures should be a good 5 to 10 degrees
cooler on Sunday with the boundary in the area and possible cloud
cover/precip.

The strong mid/upper level low pressure is still on track to dig
southeast out of central Canada on Monday. A reinforcing shot of
cold air/secondary front looks to bring the next best chances for
showers and thunderstorms during the day Monday. The ECMWF does
track the system further west and south, which means more mid/upper
level support over eastern KS and the possibility of more widespread
precip. It also shows decent instability on the order of 1000 to
1500 j/kg, and better deep layer shear, which may support strong to
severe storms Monday afternoon and evening. This strong system will
usher in a unseasonable cool air mass into the region. Temperatures
from Tuesday night on will rival record lows and cool highs. An
expansive surface high pressure takes over keeping the forecast dry
through the rest of the extended.

&&

.AVIATION...(For the 18Z TAFs through 18Z Saturday Afternoon)
Issued at 1244 PM CDT FRI JUL 11 2014

VFR conditions will dominate. Should have last batch of isolated
high-based SHRA ending shortly as upper ridge builds. Less humid
low/mid levels keeps any low cloud from reforming tonight. A few
gusts possible in increased mixing around 22Z, with more
persistent gusts expected by 16Z Saturday.

&&

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

$$

SHORT TERM...67
LONG TERM...Sanders
AVIATION...65





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