textproduct: Kansas City/Pleasant Hill

KEY MESSAGES

* Gray conditions continue, largely through end of week - Low stratus along with periods of fog, drizzle, rain - Temps above freezing limit impacts * Best accumulating rain chances tonight through Friday - No hazardous weather expected

* Mild December temps give way to colder temperatures next week, Tuesday onward

DISCUSSION

Issued at 411 AM CST Thu Dec 26 2024

Hopefully everyone had a good Christmas indoors, because outdoors conditions continue to be quite gray and dreary. Across the region low stratus and fog continue remain, now with the addition of light drizzle. Dense fog remains over eastern areas of the CWA, largely in conjunction with the Dense Fog Advisory issued with the forecast package yesterday afternoon. Guidance has remained fairly consistent on a slow westward and northward migration of sub-1 mile visibilities this morning as a weak warm front lifts ahead of the inverted surface trough over SW Missouri. This may result a short- fused dense fog advisory over western areas of the CWA, including the KC metro. However, guidance may be responding to deepening moisture profiles/moisture advection and increased intensity of drizzle (if not light rain). Will continue monitor for need of the advisory this morning. Regardless, there will be patchy to areas of fog and low-lying areas may be dense throughout the CWA/outside of the existing advisory. Fortunately, temperatures are above freezing and will slowly rise through the day, limiting any travel impacts. Bigger potential travel impacts may revolve around aviation and airport minimums. Regarding temperatures, given under performance last couple of days and no real substantial change, have blended in NBM 25th percentile to bring down temperatures a couple degrees from baseline NBM. With persistent weak WAA, this still pushes temperatures warmer a couple/few degrees, into the mid 40s to low 50s from NW to SE.

By this evening, southern stream shortwave trough/cut-off low over Texas panhandle will begin a more NE path and approach the area. This will continue already persistent moisture advection and isentropic lift, further deepening moisture profiles. Prior to the arrival of deeper mechanical lift tonight, drizzle to periods of light rain will be moist prevalent with greatest accumulations over S/SE CWA. Widely under a tenth of an inch through midnight tonight. Deeper mechanical lift arrives overnight, switching areas of drizzle over to light rain and allowing potential accumulations overnight up to around 0.20". No thunder expected with model trend continuing to push any MUCAPE further S/SE and outside of the CWA. NW areas of the CWA may only receive a few hundredths of an inch QPF through today and overnight. Fog remains likely once again with plethora of guidance depicting visibilities once again under a mile over much of the CWA. Would not be surprised if another round of Dense Fog Advisories will be needed, but will allow the next shift time to assess and to avoid confusion with current/ongoing advisory. This system begins to fill and exits to the NE early Friday morning.

Quickly on the heels of the exiting wave will be a northern stream shortwave trough affecting the area Friday. There will be less low- level thermodynamic/isentropic support, but with existing/antecedent low level moisture and nothing scouring it out, stratus and periodic drizzle may continue early Friday ahead of arrival the deeper lift by late Friday morning and through the afternoon. An additional tenth to quarter inch of precipitation may result with this wave prior to exiting Friday evening/night.

Into the weekend, the southern and northern streams remain active with additional shortwave activity traversing the region. Deterministic guidance would suggest the potential for additional light precipitation Saturday night into Sunday, though ensembles are less bullish with majority depicting a dry weekend. To the end, see no strong reason to deviate from the predominantly dry NBM. Temperatures do look to warm a few more degrees in response to southerly to westerly prevailing winds, potentially pushing temperatures into the 50s for much of the area.

Into next week, deterministic and ensemble guidance have latched onto another northern stream shortwave trough. There are some subtle discrepancies in timing and track, but looks to return precipitation chances Monday night into Tuesday from central Missouri northward into Iowa. This system will be accompanied by more robust surface cyclogenesis than previous systems. That will mostly be notable in its helping user in a colder air mass and temperatures down back towards or just a bit below normal Tuesday onward. The large scale pattern too becomes more amplified in nature, looking to keep the area on the cool side of NW flow.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 520 AM CST Thu Dec 26 2024

Poor conditions will continue to prevail with LIFR conditions likely to prevail throughout. Possibility for a brief window of IFR conditions during daytime hours if ceilings can lift, but does not appear likely with ongoing -DZ and general saturation within low levels. Expect ceilings to be around 300 to 400 ft daytime before regressing back after 00z, with potential to broach KMCI minimums at that point. Visibilities unlikely to reach P6SM for any significant periods of time, if at all. Rather, 1SM to 4SM to prevail daytime and potential for <1SM evening/overnight. Winds to remain light out of the E/SE, going more variable after 00z.

EAX WATCHES/WARNINGS/ADVISORIES

MO...Dense Fog Advisory until 10 AM CST this morning for MOZ006>008- 015>017-023>025-031>033-038>040-044>046. KS...None.