12/01/2022, 5:48 pm EST

U.S. Week 2-4 Outlook: Steadily, -AO/-NAO causes a colder national pattern.

Highlight: Steadily, -AO/-NAO causes a colder national pattern. Chart of the day: Titanic blocking ridge pattern first half of December. Discussion: Both the North Atlantic oscillation (NAO) and arctic oscillation (AO) dip to -3.0 to -3.5 later next week which is represented by the 500 MB anomaly ridge pattern over Greenland throughout the first half of December. Gradually, the U.S. turns cold in this pattern. Week-2 Ahead Forecast valid December 12-18, 2022: Cold sprawl. Discussion: -AO/-NAO steadily cause a cold pattern to sprawl across the U.S. as mid-December approaches. Generally, dry weather accompanies the East cold while the prevailing storm track brings more snow to the West. Week-3 Ahead Forecast valid December 19-25, 2022: Cold pattern persists. Discussion: Cold pattern hangs on as -AO/-NAO persist Christmas Week. Snow bias is in the West. All states are colder than normal except the Southwest U.S. Week-4 Ahead Forecast valid December 26, 2022-January 1, 2023: Cold pattern eases. Discussion: The last week of December indicates moderation and south of snow cover temperatures could easily be warmer than shown. Most of the anomalous precipitation remains over the Northern Rockies and Louisiana.
11/21/2022, 5:04 pm EST

U.S. Week 2-4 Outlook: More cold (and snow) and less warm areas in U.S. week 2-4 outlook.

Charts of the day: First and second third of November 2022 temperature anomalies. Discussion: November 2022 has featured two extreme thermal patterns. The first third of November featured unusually mild temperatures across the Central and East U.S. while the West was cold. The second third of November 2022 was cold to very cold for almost the entire U.S. except the East Coast. Week-2 Ahead Forecast valid November 28-December 4, 2022: Cold and snow Northwest to North-central. Stays chilly in New England. Discussion: Regenerating cold across deepening snow cover across Western Canada to the Northern U.S. The California to Upper Midwest stretch is snowy. The Gulf States are the warm zone. Week-3 Ahead Forecast valid December 5-11, 2022: Warm South/cold North. Discussion: The upper air forecast by ECM supports a warmer than forecast regime across the southern half of the U.S. not dissimilar from the previous forecast. However, despite weak support aloft for cold air, the expansive Northern U.S. snow cover forces Northern U.S. cold which may also include New England. Week-4 Ahead Forecast valid December 12-18, 2022: West/Northwest are snowy, colder than indicated. Discussion: ECM indicates a longwave upper trough extending from Northeast Canada to California. An attendant storm track stretches from California to the Central States and features mostly snow. The Southeast warmth could be stronger.