819
FXUS63 KEAX 112307
AFDEAX
Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
607 PM CDT Tue Mar 11 2025
.KEY MESSAGES...
* After being a bit cooler today, much above normal temperatures
continue through Friday
- 20+ deg F above normal highs
- KC area records low 80s this week
* Strong storm system moves across Plains Friday into Saturday
- Windy/gusty conditions expected
- Conditional severe thunderstorm risk
- Elevated fire weather conditions possible
* Cooler, closer to normal weekend, then warming again next week
&&
.DISCUSSION...
Issued at 302 PM CDT Tue Mar 11 2025
Quiet conditions prevail over the region today with nary a
significant disturbance within a couple/few hundred miles. Upper
level pattern yields predominantly split zonal flow and broad 500mb
ridging across much of the CONUS east of the Rockies. Large upper
low over Hudson Bay sliding across the northern Great Lakes has
allowed surface high pressure to build in over the Northern Plains
and western Great Lakes, pushing a cool front into portions of
northern Missouri. Concurrently, elongated area of surface low
pressure finds itself draped across central Missouri. With regard to
sensible weather, this will prevent cool front from moving too much
more southward over Missouri today and yield 15 to nearly 20 deg F
high temperature differences from N to S across the CWA, with I-70
roughly the delineation from the cooler northeasterly surface flow
and the warmer southwesterly surface flow. Ultimately, a pleasant
day regardless with highs expected to range form the low to mid 60s
near the Iowa-Missouri-Nebraska border region to the upper 70s
toward central Missouri. Very dry overall conditions continue as
well with dew point values generally in the 30s deg F. While deep
boundary layer mixing is again expected today, helping push RH
values into the mid 20s - mid 30s percent RH, winds will be lighter
across much of the area, preventing elevated fire weather (headline)
concerns. Today through Friday, have blended in NBM75th percentile
temperatures to better align with what has transpired over this
period of dry, warm conditions compared to baseline NBM guidance.
Have also blended in NBM25th dewpoints, predominantly today into
tomorrow. This also tends to align closer to available CAM guidance
which has verified current warm/dry regime better.
Through the middle portions of the week, cutoff low currently
sitting just off the southern California coast, will slide across
the Rockies and into the central/southern Plains. Its already
weakening/filling trend will continue as it takes on a negative tilt
and becomes more of an open wave. Deterministic and ensemble
guidance is in good agreement with regard to progression, pushing
its influence into the area by latter half of Wednesday and
overnight. Strongest/deepest lift remains depicted over southern
Missouri into Arkansas, leaving much of the lift over northern
Missouri and NE Kansas of the isentropic variety. And with
substantially dry air in place and no substantial moisture return
with this weakening system, a dry forecast remains for the CWA. NBM
probabilities strongly reflect this with only up to around 10 to 15%
probabilities or measurable rainfall in southern portions of the CWA
(think around Sedalia southward).
End of the work week remains the biggest weather story of the 7+ day
forecast. Large northern stream trough will dig in off the PNW coast
behind the aforementioned cutoff/filling low through the middle
portions of this week. By Thursday night/early Friday, this trough
will work across the Rockies and into the central/southern Plains.
Coupled with a >100kts jet streak support, expectation remains
across deterministic and ensemble guidance for rapid Lee
Cyclogenesis to occur. And the strength/extent of which is well
defined in various tools including ensemble situational awareness
tables (NAEFS/ENS/EFI/SOT) with near to extreme climatological
values for this time of the year. Further, the Euro EFI/SOT overlap
signifies additional confidence in potential extreme/rare nature
among the ensemble members. System too will be quite mature by the
time it reaches the area, seen via its taking on negative tilt by
the time it comes off the Rockies. This both complicates and
simplifies different aspects of the forecast for Friday into
Saturday.
Among the higher confidence aspects are the increasing surface
pressure gradient/strong sustained winds and gusts, and continuance
of much above normal temperatures (upwards of 25 deg F above
normal). NBM probabilities for wind gusts in excess of 45mph are
seemingly muted a bit, appearing to largely be influenced by some
expectation for shower/storm development to limit deep mixing. It
should be noted though, that just to the west in Kansas and Oklahoma
that areas that remain dry slotted/dry yield wind gusts well into
the 50s if not 60s mph are depicted within deterministic Euro/GFS as
well as their ensemble means. Can glean uncertainty among ensemble
members with increased spreads into Missouri due to that uncertainty
in where/when/if showers/storms develop. Areas that remain dry
slotted/dry appear increasingly likely to experience the higher end
wind gust potential (50s/60s). Takeaway should be that it will be
windy out of the south regardless, but strongest of wind gusts will
occur in areas that remain dry throughout. This too will also
introduce a period of elevated fire weather conditions. The deeper
mixing potential too would further drop dew point/RH values and
potentially introduce period of Red Flag Warning, especially with
the very strong wind gust potential. Keeping an eye on the need for
wind and/or fire weather headlines for the Friday time frame.
Of lesser overall confidence is the potential for
rain/showers/storms/severe storms. Again, the mature wrapped up
nature of this system will present challenges on this front, in
large part with what the areal potential and peak strength potential
are for showers and storms. Initiation within the CWA is expected
along and ahead of a pseudo-dry line wrapping up into the low. Ahead
of the dry line, speed of the system will limit any substantial
moisture return, yielding
NWS EAX Office Area Forecast Discussion