Area Forecast Discussion
Issued by NWS Topeka, KS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
930
FXUS63 KTOP 280416
AFDTOP

AREA FORECAST DISCUSSION
National Weather Service Topeka KS
1116 PM CDT SAT AUG 27 2016

...AVIATION UPDATE...

.SHORT TERM...(This Evening through Sunday)
Issued at 318 PM CDT SAT AUG 27 2016

A weak surface boundary currently stretches from central KS into
northeast KS. Low level moisture in the form of a cumulus field
resides along and south of the boundary. The surface winds are calm
near the boundary while more southerly south of the boundary.
Therefore one could imply fairly weak convergence across the area.
Soundings show that the cap may erode this afternoon mainly across
east central KS where the cap appears to be weaker so perhaps an
isolated storm could develop. There are no obvious waves within the
flow aloft, although some energy may be moving over western OK,
which may provide lift for some storms as well. The coverage appears
to remain isolated to scattered at best as depicted by most of the
model guidance. The models continue to struggle with the lack of
forcing overnight, and therefore confidence in chances are low at
his point. Models do suggest storms may develop this afternoon in
southwest KS in response to the wave, and then try to move into
central KS later tonight.

Winds will be relatively light tonight, but the models suggest the
chance for mid level clouds. Given the recent rainfall a brief
period of fog could be possible especially with any clearing skies.
Some elevated showers and storms could linger through the morning
hours tomorrow, which is evident on the NAM soundings. The same
scenario as today will be possible tomorrow with sufficient low
level moisture, a lack of forcing, and a weak cap in place. So have
kept generally low chances for storms across most of the area. Any
storms able to develop today through tomorrow will struggle to
produce any severe threats given the weak shear and poor lapse
rates. Perhaps localized strong wind gusts are possible during the
afternoon and early evening hours given the cape in this
environment.

.LONG TERM...(Sunday Night through Saturday)
Issued at 318 PM CDT SAT AUG 27 2016

Sunday night through Tuesday...Weak flow aloft during this period
with no upper systems of note.  Some models hint at weak
disturbances drifting eastward in this weak flow.  That combined
with surface boundaries forecast to remain over parts of eastern KS
and surface heating in an airmass characterized by near 70 degree
dewpoints, should lead to isolated to scattered thunderstorms during
the afternoon continuing on into the late evening hours.  Best
chances during this period may be over north central KS near where
both NAM and GEM have upper vorticity center forecast.  However,
confidence in location of higher POPs is not high.

Stagnant surface conditions should lead to lows in the 65 to 70
degree range with highs around the mid 80s both days.

Beginning Wednesday through Saturday night, mainly broad ridging is
progged to build over the region with perhaps a series of minor
waves advecting into portions of the Central Plains by late Friday
into Saturday.  This leaves northeast and east central Kansas under
the influence of a subtropical airmass the entire forecast period
and conditionally unstable.  That said, have kept POP forecast
slight to chance POPs with the main activity expected to be
diurnally driven but probably below severe limits at least until the
Friday time frame.  Depending on the strength of the eventual
shortwaves pulling out of the Central Rockies, shear profiles may
increase enough to support stronger storms during the overnight
hours Friday into Saturday time frame.  But any frontal feature
appears to be weak or ill defined at this point, so low level
convergence likely will be limited.  The main focus for lift appears
to be the veering of a LLJ into the night time hours.  Confidence in
this set-up is low at this time, but something to watch.  Near
normal highs and lows expected throughout the period with highs
around the mid 80s and lows in the mid to upper 60s.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday Night)
Issued at 1116 PM CDT SAT AUG 27 2016

There remains no obvious focus or forcing for storms. Models are
not that excited about fog or stratus either. Therefore a VFR
forecast is expected to persist. Convection could redevelop Sunday
afternoon in the heat of the day, but predictability is to low to
consider a mention in the forecast.

&&

.TOP Watches/Warnings/Advisories...
NONE.
&&

$$

SHORT TERM...Sanders
LONG TERM...Drake/GDP
AVIATION...Wolters



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.