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

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000
FXUS63 KEAX 122159
AFDEAX

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
359 PM CST Thu Jan 12 2017

.Discussion...
Issued at 359 PM CST THU JAN 12 2017

Short Term (Tonight - Sunday night):

A dangerous and potentially crippling ice storm is expected this
weekend as several rounds of prolonged freezing rain is expected.
Travel will be extremely dangerous and roads may become impassable
and power outages may result from ice accumulating on trees and
powerlines. Precautions should be taken to be prepared if power is
lost or if you are traveling and your car becomes disabled.

Tonight will be the calm before the storm as an Arctic high will
move into the Upper Midwest and impinge on the area continuing to
pump cold air into the region. The cold air in place will set the
stage for the freezing rain event. Lows tonight will be in the lower
teens to the lower 20s.

The synoptic set up for tomorrow is...the main system in the form of
an closed upper level low will drop south along the California coast
to off the Baja Coast. This will allow for a Pacific moisture plume
to begin to filter into the region. A mid-level ridge of high
pressure over the southeastern CONUS will allow the western Gulf to
open up and moisture to spread north into the region. At the
surface, the aforementioned Arctic high will keep cold air in place
while the front that came through the area yesterday, which brought
the colder temperatures, will reside across central Arkansas.
Tomorrow morning Gulf moisture will begin to override the cold front
and allow for light freezing rain to move into the southern CWA.
This freezing will expand slowly north through the day Friday
affecting areas mainly along and south of Interstate 70 during the
day. High tomorrow will range in the 20s. Tomorrow night, light
freezing rain will continue to expand northward with the entire CWA
experiencing light freezing rain. Saturday the freezing rain will
continue as highs are only expected to reach the upper 20s to lower
30s. However, the freezing rain will be scattered in nature and
there actually may be a lull in activity for periods of the day. The
best chance for seeing moderate ice accumulation on Saturday will be
across east central Kansas and central Missouri where a quarter of
an inch of ice will be possible.

The greatest chance for moderate to heavy freezing will occur in the
Saturday night to Sunday timeframe as a lead shortwave ejects out
from the main upper level trough which by Saturday night will have
moved into northwestern Mexico. Moisture will be plentiful as
Pacific moisture and Gulf moisture being pumped into the area will
allow PWAT values to rise to near an inch. The entire CWA will be
below freezing Saturday night with temperatures ranging from the
lower 20s to near 30 allowing for an additional tenth to quarter of
an inch of ice accumulation south of Highway 36 and lighter
accumulation north. The amount of ice that we receive on Sunday will
hinge on how quickly we warm above freezing. As has been the case
the past several days the EC and Canadian have been colder solutions
with the NAM and GFS warming conditions faster on Sunday. The
preferred solution right now is the colder EC as the Arctic high
residing to the north of the area should make it difficult for the
warm front to lift north across the area as quickly as the NAM and
GFS depict. Consequently this should lead to most of the area with
the exception of the southern forecast area to accumulate another
tenth to quarter of an inch of ice before temperatures warm above
freezing. This will also be the window Sunday) where the northern
CWA, north of Highway 36, which may not experience a lot of freezing
rain through this event will get some moderate ice accumulations.
Especially with the colder EC not lifting the freezing line across
northern Missouri until midnight on Sunday. All told, accumulations
of 1/4 to 3/4 of an inch are expected across the CWA with the
northern CWA experiencing the lower end and the southern and western
CWA experiencing the higher amounts. Consequently, a Ice Storm
Warning has been issued from 15Z Friday until 06Z Monday.

Medium Range (Monday - Thursday):

By Monday, the entire CWA will be in the warm sector as the closed
upper level trough will move into the central Plains. Temperatures
will rise into the 40s and 50s before a cold front pushes through
the CWA as well as bring another round of showers and perhaps a
thunderstorm as weak CAPE is evident. PWATs will still be around an
inch so modest rainfall will also be possible. Monday night the
upper low will move into the upper Midwest with rain continuing
before finally exiting the area Tuesday morning. Conditions finally
look to dry out for the middle portion of the work week with
temperatures generally in the 40s.


&&

.Aviation...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1111 AM CST THU JAN 12 2017

MVFR cigs have pushed east of the terminals and VFR conds with
sct-bkn high cirrus are expected thru the duration of the TAF pd.
Towards the end of the TAF pd ovc cigs around 4kft will move into
the terminals with pcpn holding off until after 18Z tomorrow.
Winds will veer from the north today to the NE tonight and ENE
tomorrow morning while remaining btn 8-15kts.


&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...Ice Storm Warning from 9 AM Friday to midnight CST Sunday night
     for KSZ025-057-060-102>105.

MO...Ice Storm Warning from 9 AM Friday to midnight CST Sunday night
     for MOZ001>008-011>017-020>025-028>033-037>040-043>046-053-
     054.

&&

$$

Discussion...73
Aviation...73


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