Thursday, February 27, 2020

Thursday Night - Mostly Cloudy. Low: 26-30

Friday - Mostly Cloudy. High: 42-46

Friday Night - Cloudy becoming clear. Low: 28-32

Saturday - Mostly Sunny. High: 54-58

Sunday - Becoming cloudy. Possible late evening rain. High: 62-66

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Northwesterly winds and moderate cloud cover make tonight and tomorrow similar to last night and today in terms of temperature. However, these winds will transition to southwesterly and cloud cover will clear out Friday into Saturday, causing significant warming that will continue into midday Sunday. At that point, clouds will return as low pressure from the west brings moisture and the possibility for precipitation in the evening.
Forecasters: Lieberman, Ritter
Issued:  5:00pm: February 27, 2020

Technical Discussion (The nerdy stuff we are discussing in class)
A general blend of the GFS and NAM was supplemented with SREF plumes. The WPC recommends a general blend. At 250MB, a jet max is located northeast of New England and meridional flow dominates the CONUS with a longwave trough centered from Ontario to the Gulf of Mexico. At 500MB, meridional flow is reflected downward and a significant low pressure system is centered over the Great Lakes and southern Ontario. At 700MB, it is clear that the low is not stacked as the center is located over eastern Ontario, further east than at 500MB. This trend continues down to 850MB where the low is centered slightly further east over the border of Ontario and Quebec. At the surface, the effects of the low are negligible for central Missouri and a stationary front is located on the Missouri Iowa border.

Going forward, both the GFS and NAM show zonal flow setting in from west to east at 250MB as the cyclone matures and fills in and the longwave trough moves east and out of the CONUS. A jet max oriented west-east moves east along the southeast US putting Missouri in the left exit region. This is reflected at 500MB where flow will transition from a more northerly component on the backside of the low in Missouri to westerly as zonal flow sets in. Additionally, a ribbon of higher rotational energy associated with the backside of the cyclone will pass over Columbia Friday evening. Soundings indicate UVM; additionally, the GFS and SREF plumes indicate trace precipitation is possible. However, both the NAM and GFS show insufficient moisture in soundings and inspire very little confidence for precipitation.

Both soundings and 850MB RH charts show moisture clearing out Friday night into Saturday morning. Additionally, as zonal flow sets in aloft, significant veering is observed along with tight pressure contours running perpendicular to thickness contours creating multiple solenoids over the greater Missouri area. Therefore, significant WAA is expected along with radiational heating throughout Saturday and persisting until late Sunday. This will result in unseasonably warm and increasing temperatures through the forecast period.

Midday Sunday, a small disturbance shows moderate rotational energy entering Missouri. This is complemented with moderate UVM according to both NAM and GFS soundings. However, moisture will likely be insufficient for precipitation until late Sunday. Future forecasters should monitor the energy of this disturbance and moisture advection.

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