Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO
FXUS63 KEAX 271742
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1242 PM CDT Sat Sep 27 2014
Issued at 411 AM CDT SAT SEP 27 2014
Today - Tuesday:
Seasonably mild early Fall weather will continue during this period.
Minor day-to-day fluctuations in 925mb and 850mb temperatures favor
using persistence for high/low temperatures.
A pesky closed upper low now over south central IA with isolated
convection near its center is all that stands in the way of an
extensive region of dry conditions east of the Rockies. For today
have removed any mention of showers/isolated thunder from the CWA as
best lift resides in the eastern quadrant of the upper system which
now lies over IA. However, since this upper low is caught in no-mans
land within a broad upper ridge spanning between the two mountain
chains the operational models allow for this same system to rotate
back to the southwest and through northern MO on Sunday. This would
place the best, albeit weak, lift over northeast and central MO
during the afternoon hours. So, with that in mind will allow for
slight chance PoPs Sunday afternoon for this region.
The rest of the period will be dry with the upper ridge axis
shifting east across the Plains.
Tuesday night - Friday:
Medium range models continue to advertise a significant shift in the
upper pattern with increasing chances for rain starting as early as
Tuesday night and lasting through Thursday night. Model consensus
open up and lift the large closed upper low now over central CA
northeast into the Central High Plains and then almost due north
through the Northern Plains. An associated cold front could get as
far as northwest MO Tuesday night before stalling as the now open
shortwave trough heads into south central Canada.
An amplified mean upper trough will gradually progress eastward from
the western states to near the MS River by late in the week. The
front which was stalled near northwest MO on Tuesday will shift
slowly eastward in response to falling upstream heights. Increasing
amounts of gulf moisture will be pulled northward and interact with
the frontal boundary and increasing upper support to provide several
rounds of showers and thunderstorms. Moderate to heavy rainfall will
be possible over the CWA Tuesday night through Thursday night as the
surface front shifts through MO. Temperatures are likely headed
south, due to excessive cloud cover and rain-cooled air and
especially with the passage of the cold front on Thursday. The
medium range models have now latched onto this and are trending
colder so have greater confidence in going colder.
.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1242 PM CDT SAT SEP 27 2014
VFR conditions expected through the fcst period. Fair wx cu centered
between 4-5 kft will give way to clear skies overnight. Drier low-
level conditions should preclude much fog development early Sunday
morning. Winds from the south between 8-12 kts this afternoon will
weaken slighly and back to the southeast overnight.