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

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FXUS63 KEAX 201529
AFDEAX

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
929 AM CST Tue Feb 20 2018

.Update...
Issued at 929 AM CST TUE FEB 20 2018

Have expanded the winter weather advisory to the east.
Temperatures have cooled quicker behind the front with light to
moderate rain moving into the area. With temperatures falling
below freezing shortly in the expansion area, minor icing seems
likely, mainly impacting elevated surface like bridges, and
untreated areas like sidewalks or untreated roads.

In the northwestern portions of the advisory area, in
northwestern MO, it`s likely the advisory will be dropped early as
wintry precipitation moves to the east. Will give it a few more
hours and will reconfigure things as needed. Based on reports from
various sources, social media, law enforcement, NWS employees in
the Northland, the ice storm warning is on track. While
southeastern portions of the metro may not see the amount of icing
on main roads that the northwestern portions have, there is a good
amount of ice on elevated surfaces and untreated areas are slick.
As temperatures continue to cool off, main roads will likely
become slick in southeastern sections as well.

&&

.Discussion...
Issued at 431 AM CST TUE FEB 20 2018

The cold front that pushed through yesterday has stalled across
the center of MO from Joplin to Quincy. This has kept the rain and
embedded storms going overnight as well as the freezing rain. The
sub-freezing temperatures that ushered in behind the front have made
it as far south and east to a line from the Olathe, KS to
Unionville, MO. While observation sites have been reporting freezing
rain for a few hours now, not much, if anything, has accumulated on
the roadways due the road temperatures being about 32 degrees in the
northwest corner of the forecast area and mid 30s in the KC Metro.
While, road temperatures are not expected to increase, it is
probably going to take a little more time for them to decrease below
freezing. This is because the cold front hasn`t moved much
keeping temperatures steady. Am starting to see a decreasing
trend in surface temperatures though, so would expect a similar
trend in the roadway temps soon as well. This doesn`t mean we
aren`t seeing any ice accumulations on elevated surfaces
vegetation though. We have received reports of up to 0.20 of an
inch on elevated surface north of the KC metro and a light glazing
in the KC metro. The front is slated to start pushing east again
this morning thanks to an upper level shortwave moving across the
Plains. As the front moves, the sub- freezing temperatures will
start to spread across the forecast area throughout the day.
Precipitation chances will continue along and behind the front
throughout the day as well. Therefore, the rain/freezing rain line
will push southeast, providing everyone with a chance for
freezing rain. Given the convective nature of the expected
precipitation and the amount of moisture coming in from the
Eastern Pacific, we expected a significant amount of ice (up to
0.30 of an inch) in the KC Metro and a few counties north of the
KC Metro. Therefore an Ice Storm Warning is in effect now through
6 PM tonight. Accumulations up to 0.25 of an inch are expected
across northern MO and northwest MO/northeast KS, so the Winter
Weather Advisory remains in effect until 6 PM tonight in those
areas.

Atchison County, KS to Harrison County, MO will continue seeing
on/off freezing rain this morning with up to 0.25 of an inch of
ice expected. The precipitation should move out by early
afternoon.

Linn County, KS to The KC Metro to Schuyler County, MO will
continue seeing on/off freezing rain this morning as well, with
more widespread freezing rain expected during the afternoon hours.
Up to 0.30 of an inch of ice is expected for KC Metro and
surrounding counties, with up to 0.25 expected along the MO/IA
border. The precipitation should move out near sunset.

Everyone else will see on/off showers and embedded storms this
morning with a change over to freezing rain around late afternoon.
Up to 0.05 of an inch of ice is possible. The precipitation should
move out by midnight tonight.

After this system moves out we will see a brief break from the
precipitation Wednesday, but a few more rounds of precipitation is
forecast through the rest of the week. Temperatures during the day
support liquid, with colder temperatures at night supporting more
wintry precipitation. There are some model differences, so things
like timing and precipitation type will need to be fine-tuned as
we get closer. The active pattern should move out of the area
Sunday.

&&

.Aviation...(For the 12Z TAFS through 12Z Wednesday Morning)
Issued at 552 CST TUE FEB 20 2018

LIFR and IFR conditions are expected to continue through the
morning across the area as the cold front stays stretched across
MO. The front is also providing on and off precipitation with
freezing rain being observed west of a line from Linn County, KS
to Putnam County, MO and rain east of the line. More widespread
freezing rain is expected later this morning into the early
afternoon, for western MO and eastern KS. The precipitation will
then start to move east with the front, exiting the STJ area
around 18Z, the KC metro around 21Z, IRK around 00Z, and central
MO closer to 03Z. As the precipitation moves east, the freezing
rain will move east with it. Around STJ should see up to 0.25 of
an inch, with the KC metro and surrounding areas are expected to
see the most ice (up to 0.30 of an inch) and up to 0.02 possible
around IRK and central MO. The lower ceilings and visibility will
exit the area with the precipitation and front, leaving everyone
VFR by 06Z.


&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...Winter Weather Advisory until 6 PM CST this evening for KSZ025-
     102.

     Ice Storm Warning until 6 PM CST this evening for KSZ057-060-
     103>105.

MO...Winter Weather Advisory until 6 PM CST this evening for
     MOZ001>007-011-012-015-016-020-023-024-031-032-038-039-044-
     045-053-054.

     Ice Storm Warning until 6 PM CST this evening for MOZ013-014-021-
     022-028>030-037-043.

&&

$$

Update...CDB
Discussion...Grana
Aviation...Grana


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