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Lenexa, Kansas 7 Day Weather Forecast
Wx Forecast - Wx Discussion - Wx Aviation
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NWS Forecast for Merriam KS
National Weather Service Forecast for:
Merriam KS
Issued by: National Weather Service Kansas City/Pleasant Hill, MO |
| Updated: 9:52 pm CDT Jun 18, 2026 |
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Tonight
 Mostly Clear
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Juneteenth
 Mostly Sunny
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Friday Night
 Chance Showers
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Saturday
 Mostly Sunny
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Saturday Night
 Chance T-storms then Heavy Rain
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Sunday
 Showers
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Sunday Night
 Chance Showers
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Monday
 Partly Sunny
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Monday Night
 Partly Cloudy
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| Lo 61 °F |
Hi 86 °F |
Lo 67 °F |
Hi 86 °F |
Lo 69 °F |
Hi 82 °F |
Lo 63 °F |
Hi 78 °F |
Lo 62 °F |
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Hazardous Weather Outlook
Tonight
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Mostly clear, with a low around 61. Calm wind. |
Juneteenth
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Mostly sunny, with a high near 86. Calm wind becoming south 5 to 7 mph in the afternoon. |
Friday Night
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A chance of showers, mainly after 1am. Partly cloudy, with a low around 67. South southeast wind 3 to 6 mph. Chance of precipitation is 30%. |
Saturday
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Mostly sunny, with a high near 86. Southeast wind 3 to 8 mph. |
Saturday Night
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A chance of showers and thunderstorms, then showers and possibly a thunderstorm after 1am. Some of the storms could produce heavy rainfall. Low around 69. Southeast wind 8 to 11 mph, with gusts as high as 20 mph. Chance of precipitation is 90%. New rainfall amounts between three quarters and one inch possible. |
Sunday
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Showers and possibly a thunderstorm. High near 82. Chance of precipitation is 90%. New rainfall amounts between 1 and 2 inches possible. |
Sunday Night
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A chance of showers before 1am. Mostly cloudy, with a low around 63. Chance of precipitation is 40%. |
Monday
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Partly sunny, with a high near 78. |
Monday Night
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Partly cloudy, with a low around 62. |
Tuesday
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Mostly sunny, with a high near 81. |
Tuesday Night
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Partly cloudy, with a low around 65. |
Wednesday
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Mostly sunny, with a high near 83. |
Wednesday Night
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Partly cloudy, with a low around 65. |
Thursday
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A chance of showers. Mostly sunny, with a high near 83. Chance of precipitation is 30%. |
Forecast from NOAA-NWS
for Merriam KS.
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Weather Forecast Discussion
201
FXUS63 KEAX 190339
AFDEAX
Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
1039 PM CDT Thu Jun 18 2026
...Updated for 06z Aviation...
.KEY MESSAGES...
- Cooler weather today with light rain showers tracking south across
the region.
- Active weather returns late Saturday through Sunday. Some
strong to severe storms will be possible. Primary threat
looks to be heavy rainfall which may lead to flash flooding.
&&
.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 135 PM CDT Thu Jun 18 2026
Current/Today:
Surface high pressure resides over KS and spans into MO with
cyclonic flow aloft. This morning a few impulses are rounded
through the upper level flow across northern MN. Mixing with
the mid level moisture we are saw scattered rain showers with a
few rumbles of thunder. Further south there is a stalled out
boundary across southern KS into the Ozarks. Along this boundary
there is more robust showers and storms. This boundary is
expected to stay south of the CWA with the main focus of any
precipitation being the wave aloft from this morning
transitioning south through the day. Model soundings indicate
some dry air through the low levels which will keep rain totals
light through the day. Additionally, much cooler temperatures
today with highs in the upper 70s.
Friday:
Surface high pressure slides east to encompass MO with southerly
return flow beginning in the afternoon. This push of warmer air
will lead to highs climbing into the mid 80s. Isentropic ascent
will also increase through the afternoon and evening hours
leading to 20% chance of showers. Weak instability in play could
lead to a rumble of thunder at times, but no severe weather is
expected.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 135 PM CDT Thu Jun 18 2026
Weekend:
Saturday a low develops in the lee of the Rockies and quickly
strengthens as it moves east into KS. Southerly flow increases
across the midwest picking up a fetch of Gulf moisture. Shower and
storm chances will be increasing through the day with a 20-40%
in the afternoon. Forecast trends have been slowing the progression
of the system with better dynamics for severe weather being
shifted to the west. The latest from SPC has the metro and areas
west and northwest in a marginal risk (1/5) for severe weather.
Timing for the stronger to severe storms look to have a later
arrival in the evening hours when better instability builds in
and a shortwave moves overhead.
Perhaps the bigger problem will be the potential for heavy rain late
Saturday through Sunday. The strong low out of the Rockies draws on
a deep well of PWATs with the GEFS climatology hinting at
values of 2" which would be over the 99th percentile for this
time of year. The 12Z suite of deterministic guidance still
shows a fair bit of oscillation in placement of a developing
MCS. Previously the GFS and Euro were spilt between taking the
path through IA or northern MO. There is growing agreement for
northern MO track. Over the last 4 runs the EFI has shifted out
of the IA and into northern MO with values of 0.80. Shift of
tales has also shown an increase to 1 allowing for some over
achievement possible. Taking a look at QPF plumes across the
region shows a noticeable uptick in the Euro family with
clustering now emerging within the 2" total QPF values. The
deterministic GFS continues to remain an outlier, even amongst
its other GEFS members showing values in excess of 3".
Model soundings show deep saturation throughout the whole column of
air beginning Saturday night with synoptic forcing increasing
through the early morning hours. Warm cloud depth is expected to be
over 10kft allowing for some very efficient rain production. WPC
excessive rainfall outlook has the region highlighted in a
slight risk with a moderate risk just over the tip of NW MO.
Stay tuned as this set up looks favorable for flash flooding and
river rises.
Early next week:
The heaviest rainfall is expected to push off to the east late
Sunday with some lingering precipitation chances for Monday.
However, each updated model run seems to be slowing the system
down a bit which may lead to a higher rain chances then
currently advertised in this forecast package. High pressure
should build in after the low exits providing quieter
conditions through the mid week timeframe.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 1035 PM CDT Thu Jun 18 2026
VFR conditions are expected through the TAF period. Light
and variable winds will shift from S/SE at 5-10 kt on
Friday, as high pressure moves off to the east. There is
a low chance (20-30%) for a shower Friday evening with a
passing disturbance, but being the last 6 hours and the low
probability I have left out any mention.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...None.
KS...None.
&&
$$
SHORT TERM...Britt
LONG TERM...Britt
AVIATION...McClure
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