Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 272315
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
615 PM CDT THU AUG 27 2015

...Update to aviation forecast discussion...

.SHORT TERM...(THIS EVENING THROUGH Friday)
ISSUED AT 242 PM CDT THU AUG 27 2015

Thunderstorm chances and degree of strength remain the challenges
in the short term. Morning convection out east provided a robust
outflow boundary that continues to reinforce in the east and
advance into south central Kansas at this hour. Clouds have also
lessened instability to the east, while elevated weak echoes have
started to develop out ahead of the surface low in southwest
nebraska into NW Kansas. True surface front appears to be just
through Goodland with dryline extending to the SSE, and a weak
prefrontal trof having become commingled with the outflow across
the central part of the state. Clouds and outflow has likely
impacted surface based instability, although lapse rates aloft
remain steep above the warm nose.

For the evening hours, expect weak echoes to continue to develop
over Central Kansas and move eastward with most activity remaining
east of Manhattan through midnight. CAPE dissipates quickly as the
evening progresses, and wind shear remains on the low end around
30kts 0-6km. NAM soundings suggest some help from LLJ in getting
storms started overnight, and along with the weakly defined front
moving through the area, should bring storms through overnight
and into Friday afternoon. A few of the storms could be severe,
but think SPC outlook keeping marginal threat in the northwest
part of our area is a good representation. Lows tonight with
clouds and precip remain around 70, with highs tomorrow in the low
to middle 80s.

.LONG TERM...(Friday NIGHT THROUGH Thursday)
ISSUED AT 242 PM CDT THU AUG 27 2015

Friday night through Sunday

By Friday evening, sfc frontal boundary is similar with guidance
positioning southwest to northeast over east central areas of the
CWA. While subsidence increases behind the trough over north central
areas, it is possible scattered convection could continue to develop
along the boundary.  Weak instability above 850 mb and 0-6 km bulk
shear up to 20 kts precludes widespread severe storms from
developing. Otherwise cloud cover will gradually clear behind the
wave Saturday morning with lows starting out in the upper 50s and
low 60s. Light cool advection from the north during the afternoon
keeps temps cooler than previous days in the 80s. High pressure
continues to build in through Sunday as highs gradually modify back
into the upper 80s and lower 90s for Sunday. No major changes were
made to this period.

Upper flow will become amplified with organized westerlies forecast
to remain displaced well NW of northeast Kansas. As a result...do
not expect any fronts to approach/pass through the area and any high
plains storms should remain west/northwest of the area given weak
flow.

In a nutshell, the extended looks dry for the most part and warm
with stubborn ridge expected to remain just east of the state
keeping any eastward progression of the west coast trough limited.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z Friday EVENING)
ISSUED AT 610 PM CDT THU AUG 27 2015

Scattered thunderstorms over central Kansas should move east to
more stable air tonight, but even so, expect areas of showers and
storms to move through northeast Kansas late tonight. Kept TEMPO
groups for thunderstorms going with slight time adjustments. The
airmass is forecast to be moist on friday and somewhat unsettled
on Friday. Not enough certainty to mention anything beyond VCTS
with prevailing VFR conditions.

&&

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

$$

SHORT TERM...67
LONG TERM...Bowen/Omitt
AVIATION...Johnson



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