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

Home | Current Version | Previous Version | Graphics & Text | 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
000
FXUS63 KEAX 061729
AFDEAX

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
1129 AM CST Wed Dec 6 2017

.Discussion...
Issued at 327 AM CST WED DEC 6 2017

Water vapor imagery with 1.5PVU pressures overlaid shows several
shortwave troughs diving southward through the Northern Plains.
Upstream observations and radar imagery show scattered light snow
occurring ahead of the leading wave. Forecast soundings show steep
low level lapse rates developing and deepening as the cold air aloft
associated with the shortwaves move overhead. This actually produces
weak, shallow instability in northwestern MO. Even though
temperatures are above freezing, wetbulb temperatures fall below
freezing just above the surface. Moisture is limited however and
think as a result, for late this morning and into the afternoon
hours, have added low PoPs with a flurry or sprinkle mention, as the
shortwave rotates through the area. It`s possible, if the forcing is
stronger, that these could be heavier but don`t be surprised to see
some snow flakes and/or sprinkle flying today.

Otherwise, persistent northwesterly flow will keep the area
generally dry. But with the northwest flow comes the chances for
several clipper-type systems to quickly reveal themselves and lead
to light precipitation that isn`t currently depicted. The one
thing that is more certain is the pattern lacks moisture and thus
anything that does happen should be light.

With regards to temperatures, another shot of colder air will move
into the area tonight and by Thursday morning we should see
temperatures in the middle teens to lower 20s. Little recovery is
expected during the day with temperatures likely staying below
freezing during the afternoon for most folks. Warmer temperatures,
but really just close to normal, are expected Friday as low level
flow becomes southwesterly. Similar conditions are expected
Saturday. For Monday, temperatures look to warm to near 50 with
southwest flow ahead of the next system. Confidence lowers into the
middle of next week as the ensemble spread in 500 mb heights really
increases over the area. Deterministic guidance shows the upper
pattern becoming very amplified across North America with a deep
trough over eastern Canada and the eastern US and a strong ridge
over the West Coast. But here we area, stuck in the middle, with
potential for a greater effect from either the ridge or the
trough. The forecast for Tuesday shows temperatures in the middle
30s to middle 40s. This could easily be 10 degrees too warm if
the deterministic models are correct. It could also too cool if
some of the ensemble members are correct.

&&

.Aviation...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1129 AM CST WED DEC 6 2017

BKN low-level clouds centered near 4kft will move into the area
this afternoon as a shortwave trough passes overhead. Northwest
winds of 10-15 kts with gusts to 25 kts will continue this
afternoon, before weakening some this evening. Winds will remain
from the northwest through the conclusion of the fcst period with
clearing skies expected after daybreak.

&&

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

$$

Discussion...CDB
Aviation...32



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