Tuesday, November 12, 2019



Tuesday Night - Partly cloudy and cold. Low: 14-18

Wednesday - AM sun, PM increasing clouds. High: 42-46

Wednesday Night - Mostly cloudy skies. Low: 24-28

Thursday - Mostly cloudy. High: 36-40

Friday - Mostly sunny. High: 40-44

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Tuesday night will remain chilly as the high pressure system moves off to the east, shifting the winds to a more southerly direction. This southerly wind will bring warmer temperatures on Wednesday, with increasing clouds through out the day. Winds begin to shift from southerly to northerly late Wednesday night into Thursday morning bringing temperatures down with a weak cold front moving in, but temperatures won't get as cold Wednesday night as they will tonight. Temperatures begin to warm again Friday as wind shifts back to the south.

Forecasters: Heaven, Savoy, Vanderpool
Issued:  5:00pm, November 12, 2019

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

12z WPC model diagnostics prefer a general model blend through forecast hour 48. After that, the 12z GFS is preferred. We have therefore gone with the 12z GFS for most of our forecast, with attention also given to the 18z HRRR and 15z SREF for short term temperatures.

Current pattern across the CONUS is rather odd for this time of year. A 1039-mb high was centered over Missouri at 20z, with a large cold front marking the leading edge of the arctic airmass stretching from east central Mexico to the panhandle of Florida. METAR reports indicate 20z temperatures in Missouri in the 20-25 degree range, which is 30 degrees below seasonal averages. RAP upper air analysis reveals the 300mb jet diving southward into the upper Midwest, before curving back north and east into New England and southeastern Canada. Thus, a meridional regime is in place over the United States.

Tonight, the hefty surface high will begin to move off to the east, causing winds to switch around to the south by the middle of the night. This will stop lows from crashing into the single digits, and it may even warm things up a few degrees as we approach daybreak tomorrow. Therefore, we have gone with lows in the lower to middle 10s, with the coldest conditions probably occurring around 06z.

For Wednesday, warm air advection will strengthen. Sunshine is likely for the first half of our day, with high clouds moving in by midday/early afternoon. This may serve to put a tiny dent in the warming. Still, it will be a rather impressive warm-up, with highs in the lower to middle 40s. This will also melt off most of the snowpack. The warm-up won't last long, however, as a weak cold front makes its way through the region Wednesday night. The air on the backside of this front will be nothing like what we are currently experiencing, but there should be just enough cold air advection to knock lows down into the mid to upper 20s for Wednesday night. Later shifts will need to monitor this closely, as models are trending downward with temperatures here. 

On Thursday, cold air advection will serve to keep temperatures down in the mid to upper 30s. Additionally, plentiful moisture in the lowest ~100mb may provide for a decent cloud deck for much of the day. We have therefore elected to introduce mostly cloudy skies into the forecast throughout the day Thursday. This too will need to be monitored by later shifts. Behind the front, sfc high will build in, causing winds Thursday night into Friday to be calm.

For Friday, the core of the surface high will pass over Missouri. Mostly sunny skies should provide just enough of a kick to get temperatures into the lower 40s, which, although warmer than most of this forecast - are still over ten degrees below average for this time of year.

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