Monday, December 04, 2023

Monday, December 4 Forecast Update

 Good day everyone.

Areas of drizzle/light rain along the shoreline in Lake County with some flurries mix in the snowbelt. 

Monday Morning Radar - 7:50am

Limited moisture so little accumulations.  Mainly wet pavement this morning with heavy cloud cover.  Temperatures remain in the mid/upper 30s this morning.  A few locations will climb to 40 in spots south.

Today's futurecast (future radar + temperatures) continues to highlight spotty lake enhanced drizzle/flurries through early afternoon. Intensity will be low.  Coverage will peak at 30-40% with a gradual drop in coverage by late afternoon/early evening.

Next system is developing along the US/Canadian border.  Clipper cold front arrives from the northwest early tomorrow.  This will be fast moving.  Arrival time is between 8 and 10am. Precipitation coverage will be higher than today.  Initially precip falls as rain then rain/snow mix later in the day as colder air arrives on the northern/western side of the low.

Any snow accumulation would be quick and brief.  Surface temperatures remain in the mid/upper 30s so snow will melt fairly rapidly.  Mainly wet pavement during the afternoon/evening commute. I chose to illustrate the snowfall coverage versus adding snowfall numbers due to the temporary nature of the accumulation.

Winds will come out of the north early Wednesday with some light snow Tuesday night/Wednesday morning with light accumulations.  Sun returns late Wednesday.

Thursday starts a 3-4 days milder period with mainly dry weather.   Yet another panhandle system arrives late Saturday/Sunday with locally steady rainfall.

Temperatures will rise into the mid 50s Friday and Saturday before the rain arrives.

Colder period starts late Sunday/Monday and last for 3-4 days next week.  Based on the depth of the cold, chances for lake effect snow development are much higher early next week.

Overall Snow Forecast through Dec 20

By the 15th, the mid month milder period will begin and last through the following weekend.

Longer Range Outlook:

The ongoing El Nino has influenced the southern storm track/rain events over the last 2-3 weeks. This will continue as El Nino continues this month and beyond.  

The polar vortex is showing signs of weakening. Why is this happening?  This is where it gets tricky. 

El Nino continues.  On top of this, other tropical influences are forecasted to enter a favorable phase for cold at the end of the month.  There is a link to high pressure over north central/Kara Sea/Siberia and its interaction with the Himalayan Mountains and ultimately the strength/position of the Polar Vortex. These interactions change the strength and depth of the polar jet stream which can influence the warming at the top of the atmosphere near the North Pole (Stratospheric Warming). This warming at the top can lead to colder conditions at the surface. This warming by itself doesn't always mean colder temps in the eastern US.  However, if the weaker Polar Vortex occurs when high pressure develops near Greenland and becomes persistent, the conditions become more conducive for colder then normal temps across portions of northern/eastern North America.  

Add the already active storm track (southwest to the northeast) and the late Dec/early January period could get pretty interesting. 

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