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

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000
FXUS63 KEAX 190931
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
431 AM CDT FRI AUG 19 2016

.Discussion...
Issued at 428 AM CDT FRI AUG 19 2016

Next 24 hours looks a little stormy with a cool weekend to follow.
Water vapor imagery this morning shows a large trough moving east
across Canada into the Hudson Bay. Lee side troughing across the
northern Plains States, in response to the Canadian trough, has
already helped establish a frontal boundary from eastern South Dakota
back into western Kansas with a warm front pointed east along the
Iowa-Minnesota border. The Canadian trough will continue its trek
east through weekend as a notable shortwave disturbance sweeps in
under the larger trough, helping amplify the Canadian trough as it
moves east of the Mississippi River later this weekend.

For today and through the weekend, the bit of shortwave energy,
dropping into Montana this morning, will help push the frontal
boundary out west towards northern Missouri through the day, likely
pushing the front to arrive in northwest Missouri late this
afternoon or this evening. Expect some thunderstorm activity to be
going up along the front as it arrives later today as the front will
be working into an environment advertised to have CAPE values
running above 2000 J/KG by this afternoon with 0-6KM shear values,
coincident with the better instability, looking to range between 20
and 30 knots. Add in precipitable water values around 2 inches, and
there is enough there to make one think that some severe threat will
accompany the storms late this afternoon or this evening. Main
threats are thought to be from large hail and damaging straight line
winds along with a flooding threat from torrential rain. Storms may
push into far northwest Missouri as early as 4 to 6 PM this evening,
taking much of the night to push east through Missouri with
lingering storms into the day Saturday. However, after tonight`s
activity expect a quite rest of the weekend as a cool surface high
oozes south, resulting in some very cool August temperatures; highs
in the 70s with lows into the 50s Saturday!

Next work week...our cool temperatures over the weekend will
moderate up a little, but still be rather nice for late August with
highs only in the 80s and lows in the 60s. Next shot at storms will
arrive mid-work week as another large trough works east across the
Canadian Plains, which might provide for more stormy weather during
the periods from Tuesday night through Thursday.


&&

.Aviation...(For the 06Z TAFS through 06Z Friday Night)
Issued at 1203 AM CDT FRI AUG 19 2016

Clear skies and a light southerly wind will dominate the early
portion of the forecast leading to some potential fog formation near
sunrise along the Missouri River valley. Patchy MVFR is possible
along this area with STJ having the best chance of going IFR being
closer to the moisture source and lighter winds. Colder air will
advect in from the south combining with daytime heating and the
lifting moisture from fog to develop a MFVR ceiling over the region
just after sunset. Most guidance has this deck around 1500ft with
coverage mainly from MCI and south. It will slowly rising with
surface temperatures into VFR ceilings around 18z. A cumulus field is
expected to stick around most the day with a chance of isolated
convection possible in the late afternoon, but the timing and
location are too uncertain to add to any TAFs as of now. A cold
frontal boundary over Nebraska will advect into NW Missouri just
after sunset moving through all TAF locations. Some guidance has the
storms coming through in a solid line, but others have it
disorganized with timing varying 1-2 hours either way. With this
uncertainty of exact timing and placement only VCTS has been added to
the TAFs for now.


&&

.EAX Watches/Warnings/Advisories...
KS...None.
MO...None.
&&

$$

Discussion...Cutter
Aviation...Barham/MJ



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