Area Forecast Discussion
Issued by NWS Springfield, MO
FXUS63 KSGF 181137
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
637 AM CDT Sat Apr 18 2015
.SHORT TERM...(Today and Tonight)
Issued at 325 AM CDT SAT APR 18 2015
Upper level low pressure over the central Rockies during the
predawn hours will slowly move east and open up later today and
tonight as additional upper level energy dives southeast across
the southern Canadian provinces. This will result in a continued
diffluent upper level flow aloft. With broad mid/upper level
ascent in place, it will be smaller scale features (e.g. mid-level
short wave troughs and theta-e advection) that provide a focus for
shower and thunderstorm activity through tonight.
The first concern for today will be a mid-level wave currently
moving northeast into southwestern Oklahoma. This wave has
triggered a large corridor of scattered convection from central
Kansas into northeastern Texas. The convection across the southern
Plains is likely being aided by an approaching upper level jet
streak from northern Mexico. Extrapolation of these lifting
mechanisms will bring this corridor of convection into far western
Missouri during the predawn hours...with activity then spreading
towards Highway 65 by mid-morning. We may also see some additional
widely scattered convection try and develop early this morning
farther east across central Missouri as short range models
indicate a weak cap in place for elevated parcels.
Precipitation chances this afternoon and this evening then become
a bit more unclear for a couple of reasons. First off, morning
convection may throw out some outflow boundaries which could
refocus convective development in other parts of the Ozarks.
Additionally, models are not indicating any real focusing
mechanisms at this time with the area being in between mid-level
short waves. Given that we will still see large scale lift across
the area with the approach of the main energy, scattered to even
numerous showers and thunderstorms will certainly remain possible.
Temperatures today will be held down by clouds and precipitation
over many areas. However, areas of central Missouri may be able to
climb into the middle 70s.
By later tonight, another mid-level wave should approach the
region from the southwest. Meanwhile, models develop surface low
pressure across the Lower Mississippi Valley and swing it north-
northeast towards the Ohio River Valley. These features should
provide additional focus for showers and thunderstorms. While
heavy rainfall will be possible over localized areas, low
confidence in the placement and spatial extent of heavy rainfall
preclude any kind of Flood Watch issuance at this time.
.LONG TERM...(Sunday through Friday)
Issued at 325 AM CDT SAT APR 18 2015
That upper level wave will track right over the Missouri Ozarks on
Sunday with a cold front moving southeast through the area from
late Sunday afternoon into Sunday evening. More showers and
thunderstorms will therefore be likely. The prospects for severe
storms have waned a bit as appreciable instability may be hard to
come by. We will have to continue to watch the hydro
situation...especially if locations pick up decent rainfall early
We will then get into a northwesterly flow aloft for the early and
middle portions of next work week. Temperatures will be below
normal with low temperatures in the upper 30s and lower 40s
appearing increasingly likely for Monday night and Tuesday night.
We will have to watch this situation closely as slightly cooler
temperatures may open the door to frost potential. Medium range
models do bring a few ripples through in the northwest flow. Thus,
a shower or two cannot be ruled out on Tuesday.
The northwest flow should then lose its grip by later next week
with global models advertising a decent short wave trough sliding
out into the central Plains to end the work week. This type of
regime should promote warmer temperatures along with increasing
chances for showers and thunderstorms as we head towards next
.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
Issued at 610 AM CDT SAT APR 18 2015
VFR conditions currently prevail across the region. Showers and
thunderstorms were continuing to develop and increase in coverage
in the KJLN vicinity. Could see some MVFR conditions with the
stronger cells through about 19z.
After that...the picture becomes a little more blurry. As the
upper low slowly traverses across the area and with no well
defined surface front...focus mechanisms for convection become a
challenge. Believe that there is a good chance of showers and
occasional thunderstorms through the remainder of the period.
However...have had to kind of broad brush the timing as confidence
is not high as to when a particular aerodrome will be affected.