Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO
FXUS63 KEAX 201712
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1212 PM CDT Wed Aug 20 2014
Issued at 1212 PM CDT WED AUG 20 2014
Have issued a small update to account for likely cooler temperatures
in the northeastern portion of the forecast area. Persistent cloud
cover is keeping temperatures from warming up as high as previously
forecast. While these clouds are thinning and may move out by peak
heating, the loss of earlier-in-the-day warm-up should limit highs in
the Kirksville area to the mid 80s.
Also added isolated shower/storms to southern portions of the
forecast area. A slug of moisture is lifting northward from Oklahoma.
Forecast soundings suggest we hit our convective temperatures south
of the MO river and higher resolution models depict isolated to
widely scattered convection developing in the afternoon. Have kept
chances less than 15% as coverage is anticipated to be very isolated.
Issued at 402 AM CDT WED AUG 20 2014
Summer. August. Hot and Humid. These are all phrases that will aptly
apply to our weather forecast for the next several days. Early this
morning water vapor imagery shows a rather messy pattern in place
across the Nation with a with a shortwave ridge axis across central
Kansas leaving a locally northwest flow in place across the Lower
Missouri River Valley. A shortwave trough is noted heading northeast
across the northern Rockies as it tries to crest the ridge in the
Plains States. Resulting lee-side enhancements have resulted in a
modest 30 to 35 knot southwest nocturnal jet, with its nose pointed
at eastern Nebraska into northwest Missouri.
Thunderstorms this morning...have already been noted on radar,
having developed off the nose of the nocturnal jet where moisture
convergence and and isentropic assent have forced some ascending
parcels above the modest CAP in place. Some hi-resolution model
solutions have this activity settling into far northern Missouri
this morning as it puts down a cold pool that moves south out of
Iowa. Not convinced that this scenario will play out as the storms
developing are shifting due east under the influence of the
nocturnal jet at this time. Still, expect there might be some storms
wallowing across north central to northeast Missouri around sunrise
as there is some potential for back building scattered convection.
Will monitor this early this morning and may pull out POPs all
together depending on radar trends. However, if any storms can get
into far northern Missouri should not be severe, but will dump
torrential rain as precipitable water values are 1.7 inches where
the storms are occurring.
After this mornings storms the focus will turn to the heat and
humidity that is more typical of August in Kansas and Missouri.
The ridge just to our west will shift a little farther east over the
next couple of days as a trough develops over the West Coast. This
will force warm temperatures into the Central Plains as the upper
level flow turns to the southwest, keeping a ridge of H8
temperatures in the low to mid 20s centigrade pinned across the
northwest half of Missouri through Sunday. This will likely result
in surface temperatures well into the 90s for most locations in the
forecast area. Currently, Thursday looks to be the most oppressive
day of the next several, but they will all be hot and humid with
heat index values ranging over 100 degrees. Today we might have a
little cloud cover that might take a degree or two off the afternoon
heat, but Thursday will likely not benefit from this. Currently,
forecast conditions for Thursday are around criteria for a heat
advisory along the Kansas-Missouri border. Will leave it to the day
shift to coordinate with neighboring offices, but anticipate a heat
advisory along the Kansas-Missouri border for at least Thursday.
However, the rest of the Summer is not a total loss. Cooler
temperatures --think 80s into low 90s-- will return to the region
Monday. This will occur as a result of a synoptic West Coast trough
trying to move east, which in turn may result in cooler air moving
in along with a return threat of thunderstorms.
.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1212 PM CDT WED AUG 20 2014
VFR conditions are expected at the terminals. There is a very small
chance for showers and storms to develop generally south and east of
the terminals this afternoon. So have kept the forecast dry for all
sites. Instead we may just see few to scattered diurnal cumulus.
Winds will back slight this evening and remain around 10 kts from the
south before veering to the southwest again and becoming gusty again
late tomorrow afternoon. Diurnal CU are likely again by the afternoon.