Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO
FXUS63 KEAX 030438
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1138 PM CDT Sat May 2 2015
Issued at 424 PM CDT SAT MAY 2 2015
Tonight - Sunday:
The combo of isentropic ascent on the 305K surface and a weakening
h7 vorticity max are the driving forces of an area of elevated
showers that has affected northern MO for most of today. The showers
are expected to exit the northeastern counties by sunset. Lacking
much CAPE will continue to leave thunder out of the forecast with
this precipitation. Associated mid-level cloud deck will also clear
from west to east this evening. Thinning high level convective cloud
debris from the CO Rockies expected to gradually spread east
Will be monitoring evolution of CO convection this evening as HRRR
has been allowing the convection to slowly weaken as it rolls off
the Front Range and across KS. No other model depicts this. The 12z
NAM does generate some weak signals as do the GFS, ECWMF and SREF.
The NAM once again generates moderate moist isentropic ascent but
not as deep as what was associated with today`s convection. All of
the models generate weak convectively induced vorticity maxima but
their locations vary greatly so confidence to low to insert any PoPs
at this time.
A strengthening low level jet on Sunday should yield a warm and
breezy day. Will maintain a dry forecast but as noted above will
monitor CO convection tonight.
Sunday night - Tuesday:
A large shortwave trough aloft tracking east across southern Canada
will force a Northern Plains cold front southeast Sunday night. Much
of the push will occur Sunday night and early Monday and as
suspected yesterday the models are not taking the front as far
south. With h5 heights increasing on Monday this looks like the
correct trend. Would not be surprised if the front never reaches
northern MO. Lacking any discernible trigger south of the stalled
front will focus highest PoPs across far northern MO and tighten the
gradient southward. Lacking confidence have lowered PoPs south of
I-70 to 20%.
As h5 heights continue to increase Monday night through Tuesday the
frontal boundary will lift sufficiently far enough north of the CWA
to basically go with a dry forecast on Tuesday. Should be able to
reach 80+ for highs on Tuesday.
Tuesday night - Saturday:
Looks like an unsettled pattern and period. While it is not likely
to rain every period there is too much uncertainty on timing the
numerous shortwaves and other perturbations that track northeast out
of the southwestern U.S. With a likely subtropical connection can
envision increasing chances for heavier convection.
The medium range models continue to advertise a shortwave trough
lifting northeast through the Central Plains on late Tuesday
night/Wednesday. Will bring convection back into the CWA Tuesday
night favoring the western portion of the region.
After this feature lifts away from the Mid MO River Valley the
operational models swing a few more through the region Thursday
through Saturday. Mid range chance PoPs seem reasonable but timing
.AVIATION...(For the 06Z TAFS through 06Z Sunday Night)
Issued at 1138 PM CDT SAT MAY 2 2015
VFR conditions are expected to persist through the TAF period.
Scattered midlevel clouds may build into the region around sunrise,
and winds will increase out of the SSW, gusting to 25 kts from mid
morning through the early evening. A thicker cloud deck may begin to
overspread the region late in the TAF period as showers and isolated
storms approach from the northwest, but no precipitation is expected
until after 06z.