Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO
FXUS63 KEAX 231138
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
638 AM CDT Thu Mar 23 2017
Issued at 420 AM CDT THU MAR 23 2017
Focus on the forecast is on Friday afternoon and evening due to the
potential for severe weather; though in general it will be a bit
active over the next week as there will be three different events
that may bring some much needed spring rains.
Satellite imagery this morning shows a ridge amplifying across the
Plains in response to the large trough swinging onshore across the
West Cost. Water vapor imagery in particular highlights the east
Pacific moisture this through is scooping up and will be bringing
with it over the next few days. Farther south, surface observations
show a frontal boundary stalled over the Red River Valley, which
will shift north quickly today with the help of the West Coast
Today and tonight...will be rather benign compared to the rest of
the forecast. The front across the Red River Valley will move north
today as the Western trough inches east towards the Plains. Over-
running moisture advection will keep the region cloudy today and may
bring some scattered showers or drizzle to the region during the
day. Any rain that occurs today wont amount to much as moisture is
still rather limited locally. We will have to wait for the more
abundant moisture advecting from the Eastern Pacific and the western
Gulf before rainfall totals get above a few hundredths of an inch.
Otherwise, with the warm front lifting north today, expect
temperatures to climb back into the 70s.
Friday and Friday night...is where our focus for weather will be
with a chance of severe weather for Friday afternoon and evening.
Models are still trying to pin down the trajectory that the upper
level trough and surface low will take as they move through the
Plains Friday and the weekend, but the latest trend does shift the
surface low a bit farther north, which would allow more instability
to advect north ahead of the surface low during the day Friday.
Looking closer at the various model data, they advertise MUCAPE
values around 1000 J/KG advecting north into western Missouri by the
afternoon hours; which will be coincident with 0-6KM shear values in
the 70 knot range by the mid to late afternoon hours of Friday; thus
inching up the potential threat of severe weather. Given the liner
shear along much of the expected line of storms, hail and damaging
winds are the main threats, but backing winds at the surface as you
move into central and southern Missouri may result in a tornado
potential across southern Missouri and points south Friday afternoon
and evening. Also, with precipitable water values running over
one inch, expectations are that any and all the these storms will
be efficient rain makers. So, while the overall expected line of
storms should be progressive, there could be enough training of
storms along the line coupled with efficient rain making to result
in localized flooding. Otherwise, while the main focus for
thunderstorms and severe weather is along the leading line of
advertised storms, the fact remains that the core of the upper
level trough will swing across Missouri Friday night, with the
cold core possibly initiating more late night thunderstorm
activity. The severe potential for any late night activity will be
very dependent on what happened earlier in the day.
Saturday through the rest of the weekend into next work week...the
potential for storms will persist through Saturday as the upper
level low and wrap around precipitation persist across eastern
Kansas and northern Missouri through the daylight and evening hours.
However, the severe threat will have moved off to our east as we
find ourselves on the back side of this system. Fore the most part
the rainy activity will have moved to our northeast by early Sunday
morning, leaving the tail end of the weekend likely rather nice.
However, our next chance for rain will arrive Sunday night and last
through Monday as a secondary trough slips in behind the trough that
brought Friday and Saturday`s weather. And, this isn`t even the last
chance of rain in the forecast, as there is a persistent single in
the mid-range and ensemble models of another rain making system
moving through the Plains towards the end of next work week.
.Aviation...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 638 AM CDT THU MAR 23 2017
Combination of low VFR to high MVFR CIGs prevail across eastern
Kansas and western Missouri this morning along with a few showers.
The CIGs should not lower any this morning as a dry southeast wind
is blowing in under the cloud deck. In fact, the afternoon hours
into the overnight hours will likely be VFR as clouds lift behind
the warm front as it lifts north. Winds will be gusty from the
southeast to start the day, but will veer to the south by this
afternoon, remaining rather gusty through the day. Tonight the low
level jet ahead of an approaching Friday and Saturday storm
system will likely induce some low level wind shear.