Ottawa, Kansas 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

158
FXUS63 KTOP 180829
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
229 AM CST Sat Jan 18 2025

.KEY MESSAGES...

- Very cold temperatures move in today and stick around through
  Tuesday.

- There is around a 20 percent chance of snow for north central
  and east central Kansas on Monday. Any impacts look to be
  minor.

- Be sure to dress in multiple layers including a hat and gloves
  when heading out these next several days.

&&

.DISCUSSION...
Issued at 229 AM CST Sat Jan 18 2025

08Z water vapor imagery showed a large upper trough over North
America with several shortwaves rotating through it. Surface obs
showed high pressure centered over western Canada and ridging
extending through the central plains with the cold front already
into the lower MS river valley.

The main change to the forecast was to spread slight chance POPs a
little more east into the forecast area for Monday. The latest
models are showing a more consistent signal for a frontogenetical
band of precip moving through central KS with the next surge of high
pressure. Most of the model guidance also shows enough saturation
with the frontogenesis for light snow to develop. And the 12Z
ensembles are showing probabilities for measurable snow from 15 to
35 percent on Monday. So have expanded the POPs from the NBM to
include more of the forecast area on Monday. Given how cold and dry
the airmass is likely to be, snow rations are likely to be around
20:1. Most ensemble members are around a half inch or less but the
envelop of possible outcomes goes up to an inch and a half (about 5
percent chance) mainly over central KS. This doesn`t seem
unreasonable since any snow is expected to be dry and fluffy. If
there is snow on Monday, impacts look to mainly be minor with some
snow on roads.

Very cold temperatures are on track to affect the area through
Tuesday, and confidence in the forecast is good. The biggest spread
in temps comes on Tuesday where the models have various solutions
for the boundary layer over the snow cover. Operational solutions
still show the center of high pressure passing across the forecast
area Tuesday morning with skies clearing out, so have stuck with the
NBM forecast for lows between zero and 9 below thinking there should
be adequate radiational cooling for temps to bottom out. The
forecast winds have also trended a little stronger for Sunday
morning. This has apparent temps flirting with advisory levels near
the NEB state line. The timing of apparent temps at 15 below is only
for an hour or so, so have not gone with an advisory at this time.
Later shifts can reevaluate the chances for reaching the cold
weather advisory for Sunday morning. Tuesday morning still looks
like the coldest for apparent temps. But winds are also likely to be
very light if not calm for some locations. So an advisory for the
entire area Tuesday morning is not necessarily a forgone conclusion.

For the end of the week, the longwave trough is progged to shift
east and should allow temps to moderate. There doesn`t appear to be
meaningful moisture advection to end the week so the forecast
remains dry with highs in the middle and upper 30s.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1036 PM CST Fri Jan 17 2025

North winds 12-16 kts with higher gusts will continue tonight and
through the afternoon before gradually weakening during Saturday
evening. Still a weak signal for some scattered MVFR ceilings during
the daytime hours, mainly further west towards KMHK, but otherwise
VFR conditions prevail.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Wolters
AVIATION...Reese