Wednesday, April 1, 2020

Wednesday Night - Increasing Clouds. Low: 46-50

Thursday - Cloudy with a possible isolated shower in the afternoon. High: 68-72

Thursday Night - Cloudy with showers possible. Low: 52-56

Friday - Cloudy with showers. High: 62-66

Saturday - Cloudy with showers. High: 52-56

 Thanks to for the icons!

Sunny skies will stick around for the rest of the day. Enjoy it, because the next few days will likely be overcast. This is due to a low pressure system which will impact the central US through the first half of the weekend. Clouds will start to increase overnight tonight as a high pressure system (which is currently producing our clear, calm weather) moves east. As the low pressure system moves closer, southeasterly winds out ahead of it will bring in moisture from the Gulf of Mexico. This will create chances for rain as early as Thursday afternoon, though the best chance will hold off until Friday into early Saturday. No severe weather is expected currently.

Forecasters: Vanderpool, Pauley, Ritter
Issued:  5:00PM: April 1st, 2020

Technical Discussion (The nerdy stuff we are discussing in class)

Model diagnostics from the WPC recommends a model blend of the GFS/ECMWF/UKMET. Therefore, this shift has decided upon the GFS for overall pattern guidance. The HRRR and NAM were used for short-term supplementary guidance as well, along with SREF and GEFS for temperature and sky cover guidance. 

Currently, Mid-Missouri weather is rather calm. Working from the top down and beginning with 250-mb wind/heights, the central US is currently under a ridge-like pattern. That ridge is still continuing to develop. The tropical jet streak is stretched from the boot heel of Missouri through Alabama, Georgia, and Florida. At 500-mb, the ridge is even more pronounced. 700-mb and 850-mb analysis revealed that the atmosphere (in the lower levels, at least) is rather moisture starved over much of the central US. However, a prominent jet max at 850-mb was observed over central Kansas. Hi-res model guidance indicates that this jet max will propagate east and strengthen over the next 18 hours, which will lead to an influx of moisture. 

Tonight, the low pressure system that is now located in Colorado will move into western Kansas by 09z Thursday. 500-mb vorticity advection will increase over Central Missouri around that time. Models suggest that vertical motion will start to increase in response to this, with moisture influx occurring around the same time. There should be enough moisture to form clouds. A line of showers should begin to form along the border of Missouri and Kansas, potentially stretching down into Oklahoma. Southerly winds will continue to support warm air advection over all of Missouri throughout the remainder of the night and into the daytime hours Thursday. Because of this, Thursday looks warm and cloudy, with isolated showers possible by the afternoon hours. 

Thursday night, mid-Missouri will remain in a regime of southerly flow. A trough approaching from the west will serve to bolster vertical motion, leading to a better potential for showers. This will be especially true after midnight, when the best support moves through. Continued warm air advection, along with overcast skies and higher dew points, will make for overnight lows in the 50s. 

Going into Friday, winds will begin to switch from south to north sometime between 15z and 21z as the cold front (attached to the surface low, which will likely be centered over southern Canada) moves in. Behind it, winds in the lower levels of the atmosphere will take on a backing profile, indicating cold air advection. During this time, a second line of showers should move into the area, mostly behind the cold front. For this round, moisture and lift will be more plentiful. However, a forecast sounding from the GFS at 15z Friday shows that CAPE -- both surface-based and elevated -- will be minimal. The GEFS concurs with this, showing only very low values of most-unstable layer CAPE. Therefore, any showers (or isolated thunderstorms) should not be severe. The rain will continue on into the overnight hours as a high pressure system starts to make its way into Missouri behind the front.

Saturday currently looks to be much cooler than the prior few days. A forecast sounding from the 12z GFS valid at 18z Saturday shows clear signs of cold air advection in the lowest 150 millibars of the atmosphere. The surface cold front will be well past central MO -- the GFS prognostic indicates that it should have reached the MO/AR border by then -- but its cold air looks to be relatively shallow. Above 850-mb, veering wind profiles suggest a continuance of warm air advection. This should continue to supply moisture, and therefore cloud cover, to central Missouri throughout the day. Because of this, temperatures look rather chilly as of now, with forecast highs in the low to mid 50s.

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