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

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FXUS63 KEAX 161129

National Weather Service Kansas City/Pleasant Hill MO
529 AM CST Thu Nov 16 2017

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 12Z TAFS through 12Z Friday Morning)
Issued at 522 AM CST THU NOV 16 2017

Light surface winds out of the northeast will quickly veer and
become southeasterly Thursday morning. VFR conditions are expected
throughout much of the forecast period as upper-level cloud cover
gradually thickens heading into the overnight hours. At that time,
winds will increase slightly and become more southerly. The main
impact will be in the form of increasing low-level moisture and
resulting MVFR ceilings after 06Z Friday, and perhaps IFR
ceilings closer to 12Z Friday. Areas of drizzle will approach the
from the south Friday morning, and should impact the terminal
sites shortly after the end of this forecast period.




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