Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO
FXUS63 KEAX 292119
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
319 PM CST SUN NOV 29 2015
Issued at 320 PM CST SUN NOV 29 2015
A different day but the same old story. The persistent Rex block
over the Intermountain West has been feeding Pacific moisture into
the region with surface temperatures only a few degrees warmer than
they were yesterday. Fortunately this has kept precipitation in the
form of rain. The main question then is how will temperatures evolve
this evening/overnight and what the resultant weather will be. The
preponderance of short-range models, as well as medium range models,
keep the forecast area at or above freezing tonight. After some
coordination with WPC, factoring in a degree or two warm bias in the
model surface temperatures and blending with a cooler LAV guidance,
temperatures still remain at or above freezing. So for now, the
threat of accumulating ice over northwestern Missouri and extreme
northeastern Kansas looks fairly low through the overnight. That
said, there is enough uncertainty and with temperatures so close, a
half degree or so error could mean accumulating ice or just rain.
Given that, have added some freezing rain mention in far
northwestern Missouri and minimal amount of ice accumulation, about
a hundredth of an inch, to better depict this uncertainty and to
blend national guidance and surrounding offices.
The other aspect of this system is the snowfall. Forecast soundings
in far northwestern Missouri show a very stout warm nose aloft. This
has been persistent and appears to be well sampled comparing
forecast sounding analysis to area 12Z RAOBS. With temperatures at
the surface already borderline for freezing precipitation, and such
a pronounced warm nose aloft, the threat of accumulating snow looks
very low for extreme northwestern Missouri and extreme northeastern
Kansas. There will be a tight gradient but for now that gradient
doesn`t look to be over the forecast area. We also don`t look to
cool off aloft until after the system passes by and we`re in the
backside of the wave and subsident area of the storm. While there
could be a few snow showers and/or flurries, the chance for
accumulating snow should have passed us by.
So overall, the next 12 to 24 hours look to be mainly wet for the
forecast area. There is a small area in northwestern Missouri and
extreme northeastern Kansas, where temperatures are close to
critical values, that may see light amounts of freezing rain
Once this system moves away from the area Monday night into Tuesday,
the rest of the forecast looks quiet with a general warming trend.
Broad high pressure builds into the middle part of the country
through mid week and by the later half of the week should be
centered to our southeast. This will allow for southerly flow.
Aloft, an upper ridge with increasing thicknesses will build into the
center of the country. This combination will allow for temperatures
to climb back into the to start the weekend off. By late Saturday
and into Sunday, models move another upper low into the middle of
the country, spreading precipitation chances through the Plains and
Lower Missouri valley.
.AVIATION...(For the 18Z TAFS through 18Z Monday Afternoon)
Issued at 1105 AM CST SUN NOV 29 2015
IFR and lower conditions are expected through the entire forecast
with off and on rain and/or drizzle. Temperatures look to remain
above freezing through the forecast so there won`t be any threat for
icing. Winds will generally be from east-northeast to the east around
5 to 10 kts.
MO...Winter Weather Advisory from 9 PM this evening to 9 AM CST
Monday for MOZ001.