Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 212259
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
559 PM CDT Thu Mar 21 2024

.KEY MESSAGES...

- Up and down, but overall seasonable temperatures continue.

- Several chances for precipitation over the next couple of
  days, highest on Sunday.

- A dynamic system impacts the area on Sunday with strong winds
  looking increasingly likely.

&&

.DISCUSSION...
Issued at 310 PM CDT Thu Mar 21 2024

Split upper flow continues across the CONUS this afternoon with a
southern stream perturbation progressing east through the Southern
Plains. Mostly sunny skies have allowed for temperatures to warm
into the upper 50s and low 60s with a light easterly breeze. The
southern stream wave stays south of the local area, but a northern
stream perturbation leads to enhanced southerly low-level flow and a
northward advancing warm front this evening and overnight. Moisture
and lift could (15-20%) support a rouge shower across far southeast
portions of the CWA this evening, but any activity would wane by 01-
02z. Recent guidance has slowed the progression of the warm front,
but it is still progged to be near the KS/NE border by 6am. Some
guidance suggests low stratus or fog lifts north behind the warm
front and lingers into the morning Friday before a cold front races
across the area. The boundary is progged to be completely through
the area by mid-afternoon with gusty north winds building in post-
frontal. Sufficient lift will be present along and behind the front
to generate some showers and perhaps even a thunderstorm. The best
chances (30-40%) reside in the far northeast Kansas where the better
moisture is progged to be. Sunny skies after the front`s passage
will be offset by strong CAA with temperatures topping out in the
50s north of Interstate 70 and in the 60s to the south.

Colder air filters in for Saturday with 850mb temperatures cooling
to -2 to -5 degrees Celsius. Another perturbation in the flow
brings a quick shot of precipitation to the area on Saturday.
With the cold temperatures in place, light snow looks to be the
primary precipitation type Saturday morning before temperatures
warm and any precipitation changes over to rain. Model soundings
continue to show dry air in the low-levels which will work to
evaporate some this precipitation before it reaches the ground.
All-in-all, not expecting much from this fast-moving wave with
ensemble means showing less than 0.1" of precipitation. Saturday
will be chilly with mostly cloudy skies and highs in the 40s to
low 50s.

A more potent trough moves into the western CONUS Saturday into
Sunday, working to deepen a surface low across eastern Colorado. A
tight pressure gradient sets up across the Plains which, coupled
with a 55-60kt LLJ, will create very wind conditions. Confidence
continues to increase in wind advisory limits being met area-wide;
the NBM shows a 50-90% chance of wind gusts of 45mph or higher with
even some potential of wind gusts approaching 60mph. Uncertainty
arises in the amount of mixing that will be had during the day with
a lead wave generating precipitation Sunday morning. If low-level
clouds scatter out ahead of the main trough, deeper mixing and
stronger winds are more likely whereas cloud cover holding on
through the day would limit mixing and gusts of this magnitude.
Chances for showers and storms maximize Sunday evening and overnight
as the longwave trough ejects through the Plains. The axis of
highest instability looks to remain in western and central Kansas,
but models suggest a few hundred J/kg of MUCAPE into western
portions of the CWA. This will need to be monitored for a high
shear/low CAPE severe weather scenario. Precipitation on the
backside of the system could change over to snow as temperatures
cool on Monday, but probabilities for 1" of snow or more are low
(30% in north central Kansas). Temperatures cool as another cold
front moves through Monday. Lows Tuesday and Wednesday mornings are
forecast to be in the upper teens and low 20s, which could be
impactful for those with vegetation interests.&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1226 PM CDT Thu Mar 21 2024

VFR conditions remain through at least early Friday when some
low stratus or fog could advect north towards terminals.
Confidence in this scenario is too low for inclusion in TAF.
Better chances for a couple hour period of MVFR cigs come as a
cold front moves through Friday morning. East-southeast winds of
10-12kts this afternoon weaken slightly overnight and veer to
the south-southwest. Winds then become gusty from the north
after the front passes in the 16-18z Friday timeframe.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 559 PM CDT Thu Mar 21 2024

There is more consensus from the models for low level moisture
advection ahead of the front and MVFR CIGS developing. So will
introduce CIGS around 1500 feet. Looks like dry air advection
behind the front should scatter out the low clouds by early
afternoon. Precip chances are to low to include in the forecast
at this time, but there is a 15 to 20 percent chance for some
light rain with the FROPA.

&&

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

&&

$$

DISCUSSION...Flanagan
AVIATION...Wolters


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