2:00 PM (Thursday) | **Colder-than-normal pattern likely to continue through November across much of the nation**

12Z GEFS forecast map of 5-day average 850 mb temperature anomalies in days 6-10 features a wide area of colder-than-normal; map courtesy NOAA, tropcialtidbits.com

Overview

Hundreds of daily low temperature records were set this week in the eastern two-thirds of the nation and, at several sites, the all-time low temperature for the month of November was recorded.  Monthly records that have been set for November are quite impressive indeed as they’ll typically take place in the last week or so of a given month during this time of year.   Computer forecast models have been somewhat mixed recently in their temperature anomaly predictions for the US during the remainder of November, but it appears to me that the colder-than-normal pattern will continue right to the end of November for much of the eastern two-thirds of the nation.

12Z GEFS forecast map of 5-day average 850 mb temperature anomalies in days 11-15 features a wide area of colder-than-normal; map courtesy NOAA, tropcialtidbits.com

Details

The month so far has been 3 degrees (C) below-normal across the nation with only the western US and southern half of Florida on the warmer side of normal.  All indications are that the colder-than-normal pattern for much of the eastern two-thirds of the nation will continue right to the end of the month.  In the short term, temperatures could actually reach the 50 degree mark on Friday in the I-95 corridor region, but that is still below-normal for the middle part of November.  In addition, a cold front will push through the Mid-Atlantic/NE US tomorrow night and its passage will result in temperatures some 10-15 degrees lower for the weekend in the DC, Philly, and NYC metro regions. 

The month of November so far has been around 3 degrees (C) below-normal across the nation; map courtesy Weather Bell Analytics, NOAA

Looking ahead to the latter stages of November, computer forecast models have been somewhat mixed in recent days for their temperature anomaly predictions.  Most of these same models, however, have been underplaying the influx of cold air into the central and eastern US over the last few weeks and I believe that same model trend is continuing.  In fact, the very latest run of the ensemble version of the GFS has turned even colder for its late month temperature outlook across the nation. 

Another example of model weaknesses in this type of weather pattern took place near the end of October with NOAA’s climate forecast model known as the CFS.  With a week or so to go before the month of November began, this model was predicting a warmer-than-normal month for virtually the entire nation and, in some cases, a significantly warmer-than-normal month.  This model - which is updated daily - finally “picked up” on the cold air by the first of November at which time it produced a dramatically different (and colder) monthly temperature outlook for the central and eastern US. [By the way, this updated colder model solution may actually turn out to be not cold enough).  We’ll continue to monitor the trend here over the next few days in what is looking more and more like a continuation of the colder-than-normal pattern across much of the eastern two-thirds nation right through the end of November.