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Area forecast discussion 
National Weather Service Kansas City/Pleasant Hill MO
1141 PM CDT Tuesday Jul 7 2015

Update...
issued at 950 PM CDT Tuesday Jul 7 2015

Model trending towards tracking the approaching vorticity Max and
associated surface low a bit further south as the OK/Texas upper trough
lifts northeast tonight and Wednesday. 00z NAM qpf output continues
this trend of shifting the higher rainfall southeast. First day back
so went the conservative Route and trimmed away a handful of
counties on the northwest side of the current Flash Flood Watch.
One could argue being more aggressive and trimming another tier of
counties on the northwest side, possibly even the northwest portion
of the kc Metro. Will leave that decision to the midshift after
they've seen all of the operational and short term models.

Also lowered temperatures on Wednesday for much of the southeast
half of the County Warning Area where rain will fall for most of the day. Highs won't
make it out of the 60s, just like much of OK, southeast Kansas and
southern MO this afternoon.

&&

Discussion...
issued at 411 PM CDT Tuesday Jul 7 2015

Well, it still looks wet and cool for the next 36 hours with more
Summer like conditions returning for the end of the work week and
the weekend. Looking at the big picture, a rather broad trough
resides across North America with a cutoff low spinning over the
eastern Pacific. This has left the Central Plains with a locally
zonal flow under the base of the North American trough, which in
turn has allowed a nice moisture fetch to develop from the Gulf
northeast through the lower Missouri River valley as shortwave
troughs have moved though the central and Southern Plains. One of
these little troughs is currently noted slowly moving east across
Kansas and Oklahoma and it is this trough that will bring wednesdays
rain.

Wednesday...looks wet. The trough in southern Kansas will lift into
Missouri early Wednesday. The associated surface trough/low will
then track through central Missouri during the day Wednesday with
our forecast area remaining on the cool side of the low. This should
preclude much in the way of strong thunderstorm activity for
Wednesday as the low moves through, but with perceptible water
values between 1.5" and 2" moderate rain with decent accumulations
still looks possible. Models and forecast analysis point at the
heaviest band of rain likely setting up between I-44 and Highway 50
have left the going Flash Flood Watch in place for Wednesday as a
result, though the overnight shift might have enough confidence to
trim a row of counties from the north side of the Flash Flood Watch.
Additionally for Wednesday, temperatures will be very cool for early
July with afternoon highs only in the 70s.

Thursday...will likely be wet again and could have some rather nasty
severe weather with it if some of the models are right. Another
subtle shortwave trough is noted over The Four Corners and models
advertise that perturbation heading through the Central Plains
Thursday afternoon and evening. GFS is a bit slower and farther west
with this trough while the NAM brings it right through our forecast
area late Thursday. This will be of interest as a warm front will
likely lift north with the associated surface features as the upper
level wave moves across. If the 12z/Tuesday NAM is right severe
weather will be an issue, but if the GFS is right the severe threat
will be more out in Kansas and might not be that bad. Current
forecast reflects a compromise between the two with likely pops
across much of the forecast area by Thursday night, with the highest
pops along the Iowa border.

Friday and through the weekend...Summer temperatures will will
quickly return with highs in the 80s and 90s. For the tail end of
the work week and weekend, the broad North American trough axis will
sweep to our east leaving an upper level ridge to spreads across the
plains. This will bring return of more normal Summer like
conditions, and should push the storm track to our north. Therefore,
while we have some on-again-off-again pops in the forecast through
the weekend the pops are not very high and are mostly focused along
the Iowa border.

Early next week...mesoscale convective system systems rolling off the northern plains might
drag there feet through northern Missouri, but the current strength
of the ridge might keep the activity out of our section of Missouri.

&&

Aviation...(for the 06z tafs through 06z Wednesday night)
issued at 1124 PM CDT Tuesday Jul 7 2015

Initially, will see periods of light precipitation surrounding the
kc terminals with the exception of kstj. The latest thinking is
that the approaching storm system will stay to the south slightly
more than previously discussed. IFR ceilings are still expected to
develop around 12z, though any moderate to heavy rainfall looks to
remain to the south. The activity near kc looks to exit the area
in the early to mid afternoon Wednesday. Convection will likely
not be a factor with cool surface temperatures in place throughout
the morning and afternoon hours. Conditions will gradually
improve through the afternoon, ultimately becoming VFR by the end
of the period.

&&

Eax watches/warnings/advisories...
Kansas...Flash Flood Watch through Wednesday evening for ksz057-060-
103>105.

MO...Flash Flood Watch through Wednesday evening for moz016-017-
021>025-028>033-037>040-043>046-053-054.

&&

$$

Update...mj
discussion...cutter
aviation...Welsh

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