Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO

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FXUS63 KEAX 302316

616 PM CDT Sat Aug 30 2014

Issued at 406 PM CDT SAT AUG 30 2014

All quiet this afternoon as much of the fcst area now resides in a
post frontal airmass following this morning/s weak cold front passage.
Latest visible satellite images show developing/ongoing convection
just east of the CWA border this afternoon as convergence along
lingering boundary combines with weak destabilization and upper
shortwave forcing from a wave now found over eastern IA. Latest look
on SPC meso page indicates best deep layered convergence remains just
east of our area but will continue with a slgt chc mention across
our far eastern zones just in case any activity does develop a little
further west than expected. Any convection that does develop will
quickly erode by early evening with loss of daytime heating. Through
the overnight...expect starlit skies with lows falling into the
middle to upper 60s...with a few low 70s possible in the immediate KC

Fcst becomes much more interesting as we head into the latter stages
of the weekend...but not before another beautiful and dry Sunday
across the lower Missouri Rvr Vly. 850 temps ranging from 16-19C this
afternoon will continue warming a few degrees on Sunday as southerly
flow again returns to the area. This should support high temps
climbing back into the upper 80s to lower 90s across most
locations...under partly to mostly cloudy skies as upper-level
moisture begins to approach from the central Plains. While we enjoy
the nice day down here...areas to our north will be under the gun for
a pretty decent severe weather event as a long advertised upper
trough and associated cold front track east from the central Plains
into the upper Miss Rvr Vly. Fortunately for us impacts
from this storm system will hold off until later Sun ngt/early Mon.

As has been alluded to in recent days...concerns by Sunday night
quickly shift to the severe situation to our north on Sunday. Fcst
models remain in decent agreement that isolated convection across
eastern NE and western IA will begin congealing into a developing MCS
during the early overnight hrs before gradually spreading south
towards northern MO/eastern KS during the overnight period. Out ahead
of this feature...moderate levels of instability will be in place
with MLCAPE values expected to range from 1500-2000 J/kg. As front
continues to head south during the early overnight...preceding
airmass will be characterized by steep mid-level lapse rates as an
elevated mixed layer plume advects east through the day on Sunday.
Quick look at high-res models supports convection extending south
into our northern zones after NE/IA afternoon convection
spreads a cold pool south along/ahead of the southward sagging cold
front. Models today seem to be a little further south with the
mid-level speed max associated with the main trough with
a low-level jet expected to increase to near 50 kts during the
overnight...plenty of shear looks to be available for organized
severe wx across northern portions of the fcst area. Convective mode
definitely difficult to pin down as bulk shear magnitudes definitely
support the possibilities of isolated cells ahead of the cold
pool...while overall bulk shear vector orientation would suggest a
linear morphology. In any event...enough directional shear and
instability looks to be in place to support damaging winds as the
main threats...while an isolated tornado or two cannot be ruled out
due to enhanced vorticity/cold pool interactions resulting with such
strong winds right off the deck. Later model runs will certainly be
interesting and if cold pool actually spreads out over our area
early Monday morning...the severe threat could quickly switch over to
hydro as the low-level jet continues to pump moisture northward.

Front to continue sagging south across the region on Monday with
continued chances for shwrs and storms. Severe threat to continue
right through the day as upper trough and associated mid-level speed
max remain positioned over the area. Front finally looks to clear the
area Monday night/early Tuesday as high pressure slowly builds into
the central Plains. This should allow for drier weather for Thursday
and Friday before precip chances increase late in the period as the
next front/upper trough approaches.


.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 616 PM CDT SAT AUG 30 2014

VFR conditions are expected for much, if not all, of the next 24
hours. Surface moisture will likely be too shallow for much haze
Sunday morning outside the KSTJ terminal. Otherwise, southerly winds
will increase in speed and gustiness Sunday ahead of a cold front
that will wash out across the region Monday.




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