Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO

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000
FXUS63 KEAX 160519
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1219 AM CDT Sat Aug 16 2014

.UPDATE...
Issued at 937 PM CDT FRI AUG 15 2014

Will be issuing a flash flood watch into mid Saturday morning for
much of our northern counties. Will have watch out shortly. A
developing southwesterly low level jet from OK into northwest MO is
fueling multi-cell low-topped convection well north of stationary
front. Precipitable water values progged to reach 2.25 inches which
is the 99th percentile. Strong isentropic ascent on the 305K surface
is aiding and will maintain lift to support continued convection
overnight as moderately unstable upstream airmass is lifted above the
stationary front. 00z TOP and OMA soundings showed skinny CAPE within
a tropical airmass. The low-topped convection is a clue to warm-rain
processes which is a very efficient rain-making process. Potential
exists for back-building and repeat convection with northern MO the
most likely destination for this activity. Have increased overnight
QPF to 1.5 to 2 inches in the watch area with potential for local
amounts to exceed 4 inches.

&&

.SHORT TERM...(This Evening through Sunday Night)
Issued at 359 PM CDT FRI AUG 15 2014

Isentropic lift along the 305K-315K surfaces across northern
Missouri has continued showers and isolated thunderstorms through
the afternoon hours. An upper level shortwave will move into
southeastern Nebraska this evening developing a surface low across
northeastern Kansas tonight. This surface low is expected to push
east in the VC of the MO/IA border tonight. Light rain and isolated
thunderstorms associated with this system are moving through
southeastern Nebraska into eastern Kansas this afternoon and will
progress eastward this evening. Tonight a 40-50kt southwesterly LLJ
will develop and nose in northern MO and we may see an increase in
coverage and intensity of showers and thunderstorms after 02Z across
northern Missouri. This upper level shortwave will then slow down
and close off tonight across swrn IA/nwrn MO tonight. This will
continue to focus the potential for heavy rainfall on the nose of
the LLJ across northern Missouri where PWAT values are ranging between
2-2.25". A flash flood watch was considered but with flash flood
guidance between 2.75-3.5" across northern Missouri any flash
flooding, if it does occur, should be localized.

Tomorrow the upper level low will push slowly eastward along the
Missouri/Iowa border with a nearly stacked surface low. A cold front
extending southwest from the surface low will be the main focus for
showers and thunderstorms. Showers and thunderstorms will continue
across northern Missouri in the vicinity of the low. Expect
thunderstorms to develop tomorrow afternoon out ahead of the cold
front south of a Kirksville to Kansas City line in an area of
differential heating. With 2000-2500J/Kg of CAPE available it is
possible that there will be enough instability to produce a few
strong to isolated severe storms despite shear and forcing being
weak. The main threats would be for damaging winds with small hail
possible. This front will push slowly east across the CWA during the
afternoon and evening continuing thunderstorm chances. By tomorrow
night the nearly stacked low will push into northeastern MO
continuing shower and thunderstorm chance across the northeastern
CWA.

Sunday, the stacked low shifts into central Illinois but there will
still be the potential for showers and isolated thunderstorms mainly
across the eastern CWA. Shower chances should diminish by Sunday
evening as the upper system continues to push eastward into the Ohio
River Valley.

.LONG TERM...(Monday through Friday)
Issued at 359 PM CDT FRI AUG 15 2014

For the beginning of the work week...much less amplified flow and so
there will continue to be a chance of showers and thunderstorms as
minor shortwave troughs move through the upper flow. Further north in
the Dakotas the pattern includes a deeper trough which will induce
surface cyclogenesis and better chances of precipitation.

In addition...given this pattern temperatures will remain in the 80s
to lower 90s with ample moisture from the south thanks to the low
level fetch off the Gulf.

The northern plains trough mentioned above will move into the
western Great Lakes area and lower heights over the Missouri Valley
through mid week. This will keep the chances of showers and
thunderstorms through Wednesday.

Upper ridging amplifies in the Central US late in the week...drying
the CWA and turning up the heat a bit for Thursday and Friday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 1215 AM CDT SAT AUG 16 2014

Widespread showers with embedded thunderstorms producing very heavy
rains will affect the northern third of MO overnight. Isolated
convection over east central KS and west central MO with convection
increasing in coverage further east into central MO. The
precipitation will gradually shift east overnight. Additional showers
and thunderstorms are expected Saturday afternoon and evening from
west central into central MO as a weak cold front moves through.

IFR ceilings with MVFR fog over northwest MO and northeast KS will
nudge southward towards KMCI overnight but don`t think they will
reach. Otherwise, VFR conditions with considerable mid-level
ceilings. As a cold front drops southeast through the region
southeast and southerly winds will give way northwest winds with the
passage of the front.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...FLASH FLOOD WATCH until 10 AM CDT this morning FOR MOZ002>008-
     012>017-023>025.

&&

$$

UPDATE...MJ
SHORT TERM...73
LONG TERM...Adolphson
AVIATION...MJ





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