Friday, November 27, 2020

Major Pattern Change Coming...

For most of November we have been enjoying temperatures above normal, which means highs generally in the 70s & nights in the 50s.  That is about to dramatically change as the upper trough over the west shifts to the east coast resulting in much colder air coming here for the next 2-3 weeks.

You can see why in these 2 graphics.  The top one is the current upper 500 mb (18,000') flow while the bottom is the forecast for Dec. 10th.  The deep trough over the east should result in freezing temperatures over the North Shore possibly reaching the South Shore once we get into December.


You can see how cold it is out west.  Once the upper trough shifts to the east, we'll be scrambling for the heavy weather gear.


In the short term, we're stuck under an extensive cloud cover associated with a stalled frontal boundary. Temps are in the 50s & 60s north of the front while we're 75-80 south.  Dew points around 70 give us a soupy, summer like feel to the air.  Most of the rains today should be north of the Lake shifting south towards dark.  The front may briefly sag southward on Saturday before jumping back to the north on Sunday.  Sunday looks to be the wettest day before the cold dry air plows in for next week.


There remains the potential for widespread heavy rainfall (4-6"+) to our west with locally 3-5"+ amount here during the next 2-3 days.



The upper low is back over New Mexico with lots of clouds hugging the Gulf from Texas to Florida.  Expect the rain shield to shift over us later this afternoon and evening.  This will not be a pretty weekend.  Stay tuned!



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