Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO
FXUS63 KEAX 110351
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1051 PM CDT Thu Apr 10 2014
Issued at 349 PM CDT THU APR 10 2014
Short Range (Tonight-Friday Night):
This period will pretty much see benign weather with a continuation
of above average temperatures. Two weak shortwaves embedded within
the northwest flow will pass through the CWA this evening/overnight.
The lead feature will temporarily clear out the multi-layered higher
based cloudiness early this evening with a second feature following
close behind. Should see generally clear skies once this passes by
early Friday morning.
A weak cold front has moved into central MO and will eventually
stall over southern MO. Very dry air behind the cold front and
models appear to have not caught onto how dry the air is upstream.
Have lowered dewpoints across northern MO through tonight. Really
isn`t much cooling behind the front as 925mb temperatures are little
changed by Friday afternoon. So max temperatures in the upper 60s to
lower 70s seem reasonable.
While the current forecast is dry for Friday night the 12z NAM and
to a lesser degree the ECMWF show a weak signal for elevated
convection due to moderately strong warm air advection and a layer
of moisture around h8. Should the next couple of runs of both models
continue showing this will need to consider adding at least low
chance PoPs for late Friday night.
Medium Range (Saturday-Monday):
This will be a very active period as a southern stream upper trough
ejects east-northeast while a deepening upper trough dives southeast
from southern British Columbia into the central Rockies.
Concurrently, downstream pressure falls in response to the southern
stream system and departing surface high will generate increasing
southerly winds through h8. These winds will pull up moisture from
the Gulf of Mexico into KS and MO just as a slow moving cold front
edges southeastward through NE and IA. Models are in pretty good
agreement although they have slowed down the arrival of the front
over the past 24 hours. The airmass within the warm sector will
become moderate to very unstable with MUCAPES from 2000-3000 J/kg
possible over KS and northwest MO. While convection is expected to
form along the cold front Saturday afternoon the NAM/GFS/ECMWF all
develop pre-frontal convection across northwest MO. This seems to be
in response to a h7 shortwave ejecting northeast out of CO. However,
GFS/NAM BUFR soundings show an elevated mixed layer spreading across
the warm sector and effectively capping the warm sector. So, have
shifted PoPs later in the day on Saturday and focused on northwest
MO. Strong/isolated late afternoon/evening convection is possible
over this region.
Showers and thunderstorms will become more numerous with time as the
cold front sinks southeast and through the CWA. Will likely see
several rounds of convection Saturday night through Sunday night.
Some concern for heavy rains due to potential training as the cold
front will be nearly parallel to the mid level winds.
Will likely see areas of post-frontal stratiform rain Sunday night
into Monday morning until the Central Rockies upper trough axis
Much colder air will filter in on Monday with below average
temperatures likely. Will probably struggle to reach 50 for a high.
Long Range (Tuesday-Thursday):
Benign weather pattern through Wednesday as northwest flow
transitions to an unstable zonal flow. Temperatures should warm a bit
but likely remain below average.
GFS/ECMWF do signal the potential for some unsettled weather moving
into the region. GFS looks too strong with the upper system but they
both generate some precipitation. Since it`s day 7 and there is much
uncertainty on timing and strength of the next system will start off
with slight chance PoPs.
.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
Issued at 1043 PM CDT THU APR 10 2014
VFR conditions are expected at the terminals over the next 24 hours.
Calm winds late tonight will turn to the south Friday morning as the
center of the surface high slides off to the east. Southerly winds
should prevail through the day with mid-level --VFR-- clouds
beginning to advect in late Friday night.