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

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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
FXUS63 KEAX 251758

National Weather Service Kansas City/Pleasant Hill MO
1158 AM CST WED NOV 25 2015

Issued at 340 AM CST WED NOV 25 2015

The main focus for this forecast issuance remains potential wintry
precipitation Thursday evening through Friday as a trough slides
across the northern Plains and pushes a surface cold front through
the forecast area. Ahead of the front, low-level moisture advection
and isentropic lift will support increasing chances of drizzle or
very light rain today into this evening, then rain will increase in
coverage and intensity on Thursday as surface low pressure bulges
out from the High Plains and the front begins to push southeastward.
Very minor instability builds Thursday morning & early afternoon
ahead of the surface boundary, possibly resulting in an isolated
rumble of thunder or two and periods of heavier rain showers south
of I-70. In total, widespread rain amounts will reach 1.5" to 2"
from today through Friday morning, which could result in isolated,
minor flooding issues.

Elevated frontogenesis and moisture pooling just behind the surface
cold front continue to support a broad region of post-frontal
precipitation. At the same time, near-surface cold air will surge
into the region behind the front Thursday evening and night, and the
combination of cold-air advection and diurnal cooling will help
temperatures drop while precipitation is ongoing. Precipitation type
remains very tricky in this post-frontal regime, for a number of
reasons. First, warm air will be thoroughly in place ahead of the
front, with pre-frontal temperatures in the upper 50s to lower 60s.
In addition, the widespread rain ahead of the system will wet the
warm ground and make ice accumulation more difficult, and without a
break in rain even as temperatures fall, flash freezing of standing
rainwater will be unlikely. Finally, model soundings continue to
show a loss of mid-level saturation as surface temperatures drop
below freezing, hinting more at a short period of light freezing
drizzle than any significant freezing rain. As a result, the most
likely scenario, given the conceptual model for this system and the
antecedent conditions, is that temperatures will hover a few degrees
above freezing while post-frontal rain is occurring, and will not
drop below the freezing mark until most precipitation has ended late
Thursday night or Friday morning. The only exception in our CWA
could be in extreme northwest MO where temperatures will start out a
bit cooler and could drop a bit more efficiently behind the surface
front, but the threat for accumulating ice decreases very quickly to
the south and east. It is, however, important to note that better
moisture availability and colder temperatures west and northwest of
our forecast area will make freezing rain and significant ice
accumulations much more probable, so those with travel plans in
those directions should exercise extreme caution and plan ahead for
difficult travel conditions Thursday night and Friday.

The front may briefly stall near our southern CWA border this
weekend and into early next week, then cut-off low pressure that
will linger over the desert southwest this weekend will eventually
eject eastward by the end of the forecast period, allowing low-end
precipitation chances to linger through the weekend and into early
next week. Low temperatures will hover around freezing making brief
periods of mixed wintry precipitation possible, but impactful winter
weather is not anticipated in the long-range forecast period at this
time. Diurnal temperature rises will be dampened by clouds and any
precipitation, resulting in a chilly, damp holiday weekend and start
to next week.


.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1151 AM CST WED NOV 25 2015

MVFR CIGS stationed off to the southwest of the terminals as of
forecast issuance time. This area of low stratus is lagging a bit
from previous forecast, but should be in the area shortly. Expect
those MVFR CIGS to remain in the area through the evening/overnight
before eventually going to IFR with some drizzle. With forecast CIGS
around 010 it`s possible that there could be brief periods of IFR
CIGS before they go prevailing. Light rain then commences early
Thursday and will be steady through the day.


.EAX Watches/Warnings/Advisories...


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