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

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KEAX 011751
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1251 PM CDT Wed Apr 1 2015

.UPDATE...
Issued at 950 AM CDT WED APR 1 2015

Have made some significant adjustments to the short term forecast.
First, have added chance PoPs for this afternoon and early evening to
the far southeastern counties in response to MCV (mesoscale
convective vortex) lifting northeast out of northeastern OK. HRRR
has picked up on this for a number of runs and radar composites shows
scattered showers moving into southwest MO while satellite imagery
depicts accas clouds further west over southeast KS. The OK vorticity
is expected to lift to just south of the southern CWA border by mid
afternoon with scattered convection increasing with time. Have also
lowered temperatures a bit where PoPs added.

Second idea is to slow down the arrival of convection tied to the
approaching Northern Plains cold front. With the passing of each new
model run the trend has been to slow down the arrival of convection.
Considering the moisture, aka instability, will take time to arrive
in sufficient quantity to support robust convection plus the low-
level jet veers this evening which limits the eastward extent of
downstream convection have no problem pairing back the evening PoPs.
Will hold off on adjusting PoPs after midnight until the rest of the
models arrive.

&&

.DISCUSSION...
Issued at 335 AM CDT WED APR 1 2015

Quite a lot to get to this morning so we might as well jump right to
it. Water vapor imagery showing a split flow regime across the CONUS
this morning with a southern stream shortwave fueling nocturnal MCS
activity over central Oklahoma. Looking further to our
northwest...northern branch wave now working through the northern
Rockies with trailing cold front extending southwest through the
Intermountain West. Meanwhile to our south...latest sfc analysis
places stalled frontal boundary extending from southwest Missouri
east through the Tennessee Vly. As northern stream energy drops into
the Plains later this morning...strengthening southerly flow will
quickly lift this feature north through our region by early
afternoon. Following its passage...strong moisture advection to get
underway with fcst models showing mid-upper 50 dewpoints working as
far north as southern IA later this afternoon. With daytime temps
expected to warm well into the upper 70s and lower 80s...expect
plenty of boundary layer mixing as low-level lapse rates steepen with
time. For now...would not be surprised to see gusts in the mid 30 mph
range during peak heating later today. Despite strong moisture
advection from the south...strong winds combined with dry sfc fuels
will create elevated fire weather conditions later today...and will
address these concerns in the HWO and a fire weather special weather
statement.

Of more concern however will be developing convection off to our
northwest later this afternoon. As discussed in recent
days...increasing wind fields combined with moisture convergence
along the approaching front will support surface based convection
upstream across eastern Nebraska...north-central Kansas...and
western Iowa this afternoon. After developing...activity will quickly
congeal into a squall line before slowly tracking southeast towards
northwest Missouri after sunset. Overall thoughts for organized
severe across our area continue to lower this morning as models
remain consistent in advertising incoming convection should quickly
becoming elevated as it enters our region due to boundary layer
stabilization. Cannot rule out some sfc based activity working into
far northeast Missouri early tonight...but isolated severe threat
across these areas should decrease as convection continues to track
southeast overnight. With further southeastward
progression...concerns will quickly changeover to heavy rain as low-
level wind vectors become parallel to the incoming frontal boundary.
With PWATs running anywhere between 2-4 standard deviations above
normal...highly efficient rainfall will be possible...especially
across far northwest Missouri where over 1 to 1.50" of new precip
will be possible by daybreak. Lower precip amounts are expected
further downstream as convection weakens and becomes more stratiform
in nature during the early morning hrs.

Front to still linger across our region through the day on Thursday.
Some concerns for renewed severe potential across our far southern
zones by afternoon as daytime heating leads to modest destabilization
south of the front. Wind fields aloft will be more than supportive
for severe and frontal boundary position will be critical for
possible severe activity. This morning/s models now advertising a
further northward position than in recent days...so have increased
daytime highs for Thursday afternoon.

Next wave to start tracking east along the stalled front Thursday
night/early Friday. With moisture advection continuing from the
Gulf...potential for heavy rainfall exists mainly south of the CWA
before activity clears later in the day. This should set the stage
for a dry but noticeably cooler weekend as high pressure settles
south across our region. Precip chances look to increase once again
by Monday and Tuesday as another frontal boundary begins slowly
working through the area. Out ahead of this feature though...temps
look to rebound nicely heading into early next week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1236 PM CDT WED APR 1 2015

Scattered convection over southwest MO will move into parts of west
central and much of central MO after 19z and last into the early
evening hours. Generally VFR ceilings except briefly MVFR with the
strong storms.

Gusty southerly winds into early evening. Winds veer to the northwest
with passage of cold front after midnight.

Otherwise, will delay arrival of line of convection associated with
approaching cold front by a few more hours with activity crossing
into far northwest MO after midnight. Strongest storms/heaviest
precipitation should be across northern MO with activity becoming
more scattered and less intense to the southwest. Line should weaken
as it shifts southeast into west central and central MO towards
sunrise. MVFR ceilings most likely with the convection, probably
several hours of IFR over northern MO. Precipitation will end from
west to east by late morning with ceilings improving to VFR by mid
morning.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&

$$

UPDATE...MJ
DISCUSSION...32
AVIATION...MJ





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.