Why it’s so cold today in Washington, D.C.

Temperatures today, thus far, have only risen into the mid-to-upper 40s and will struggle to go much higher.

GFS model forecasts highs stuck mostly in the 40s in the D.C. region today (WeatherBell.com)

GFS model forecasts highs stuck mostly in the 40s in the D.C. region today (WeatherBell.com)

These temperatures are 10-15 degrees colder than normal.  Our “normal” high for November 4 is in the low 60s.

Our local temperatures are some 10 degrees colder than Chicago, and 3-5 degrees colder than Des Moines and Milwaukee. They are more typical of the average temperatures in Portland, Maine on this date.

Two weather features explain today’s chill in the Mid-Atlantic to Northeast:

1) A strong area of cold high pressure to the north

Map showing surface pressures in the eastern U.S. and difference from normal (color shading) (WeatherBell.com)

Map showing surface pressures in the eastern U.S. and difference from normal (color shading) (WeatherBell.com)

This circulation around this high pressure is driving cold winds from the north and northeast southward. It’s exactly this kind of high pressure system snow lovers will want to see this winter, as it’s the feature the provides the necessary cold air for snow rather than rain when storms approach from the west and south.

2) Clouds/moisture

A developing storm system in the central U.S. is pumping moisture over 1,000 miles east, helping to build a blanket of clouds over the region.

Water vapor image (NOAA)

Water vapor image (NOAA)

These clouds have blocked out much of the sunshine which might have helped us pass 50 degrees today.

The weather pattern doesn’t change much tomorrow, so we can expect a second straight cloudy, chilly day.

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