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

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054
FXUS63 KEAX 161749
AFDEAX

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
1149 AM CST Thu Nov 16 2017

.Discussion...
Issued at 302 AM CST THU NOV 16 2017

Dry conditions and slightly below normal temperatures are expected
today as northwest flow continues aloft. This pattern will
precede a more active pattern now in the early makings across the
Pacific Northwest, which will impact the local area as early as
Friday morning. Until then, the existing surface ridge will slowly
move eastward through the day, which will transition surface flow
from northerly to southeasterly by this afternoon. Upper-level
moisture advecting over a broad upstream ridging pattern will
provide for some overhead cirrus today, though ample sunshine will
continue until Thursday night into Friday morning. Deep warm
advection will overspread the area at that time, along with
increasing cloud cover, which looks to persist until early
Saturday afternoon. A non-diurnal temperature trend will commence
early Friday morning as southerly surface flow sends Thursday
evening temps from the low to mid 40s into the upper 40s to low
50s by Friday at sunrise. Surface temps will steadily climb
through the morning and early afternoon, eventually peaking in the
low to mid 60s for areas south of Highway 36. Temps in the mid
60s south of I-70 will rise just over ten degrees above normal for
November, though this will be short-lived and easily the warmest
day of the upcoming seven day period.

Increasing low-level moisture will replace the mid-week dry air
mass, which will present the opportunity for drizzle Friday
morning. The pattern looks very similar to what was experienced
earlier this week, with moisture confined to the lower-levels only
early on. Thus drizzle and resulting reduced visibility is
possible once again during the Friday morning commute. With that
said, moisture fields are slightly deeper at the lower levels,
thus could see some light rain showers mixed in with areas of
drizzle. This should transition to light rain showers by Friday
afternoon as moisture continue to deepen and as at least some
instability develops ahead of a cold front. This could also lead
to isolated thunderstorms Friday afternoon and evening, though the
severe weather threat continues to be unlikely. Given the
displaced mid-level trough from surface forcing, the greatest
chance of precip looks to be post-frontal at this point,
coincident with the passage of the trough axis. There is at least
a hint that the thermal profile could support a brief period of
a wintry mix across northern Missouri Saturday morning. However,
there are still discrepancies in a saturated vs unsaturated
dendritic growth zone, and 850 hPa temps overall look to remain
near or above freezing across northern Missouri. As of now, going
with an all liquid rain event for the area Friday night into
Saturday, considering the antecedent thermal profile and the
progressive nature of the front itself.

Below normal temps will continue through the weekend until a brief
warmup returns temps to slightly above normal on Monday. The
remainder of the week looks dry as of now, though a progged embedded
disturbance moving through the region during the mid-week will be
worth watching. As of now, moisture fields looks meager for much in
the way of precip. Thanksgiving Day continues to look slightly on
the cool side with dry conditions expected.

&&

.Aviation...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1147 AM CST THU NOV 16 2017

VFR conditions will prevail for the remainder of the daytime
hours, but will see conditions deteriorate through the overnight
hours as low stratus moves in. Higher certainty for IFR/LIFR CIGS
during the early morning hours on Friday, accompanied by some
light drizzle knocking VIS down to MVFR/IFR levels. Could see some
marginal improvement through the day on Friday, but MVFR/IFR
expected through the duration.

&&

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

$$

Discussion...Welsh
Aviation...Leighton



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