New and Improved 30 day Global Forecasts
New and Improved 30 day Global Forecasts
New and Improved 30 day Global Forecasts
Mild temperatures by early winter standards across the vast majority of the U.S. during the 1st weekend of December represent early stages of a multi-week warming trend which recent model forecasts prolong deeper into late month. Even the Northeast which verified coolest in November is on track to experience only one additional modest cold air outbreak (3°-6° below average) peaking Wednesday and Thursday before temperatures skyrocket more than 10° above average (50s) by next weekend (Dec 9-10). This initial surge of late week Eastern warmth is part of even warmer Southwestern (80s) to central U.S. (70s) midweek temperatures that latest model forecasts only briefly interrupt with seasonal level cooling next weekend, before warming back several degrees above average early the following week (Dec 11-12). This 2nd surge of western-central U.S. warmth in mid December was nonexistent in model runs all last week, and more importantly includes all of Western Canada where prior forecasts indicated onset of prolonged arctic air transport. Most extended range models still gradually shift colder across Western Canada but later in December at a much slower rate which delays significant U.S. cooling until the final week of the month at the earliest. Even then intensity of U.S. cooling between Christmas week and early January appears limited (mainly seasonal) by relatively mild split jet stream flow typical of El Niño.