The long awaited cold northerly outbreak seems to have slipped back in each successive run of the models, but there seems to be no doubt that the first ten days of April 2021 will be cold, and perhaps very cold in the north, as a cold trough extends southward from the Arctic with 1000-500 hPa thicknesses falling well below 528 dm and perhaps 510 dm for a time. These thickness values are as low as any we saw at anytime during the winter just ended. I say northerly outbreak, but winds on the surface will generally be just west of north for much of the time. If the above surface charts of the ECMWF model aren’t dramatic enough for you look at this sequence of 850 hPa (~5,000 feet) temperature charts that demonstrate just how cold it is by height, but as always forecasts beyond T+120 should always be taken with a large pinch of salt. The contrast between the recent warmth of this week and this abrupt change back into winter means that Easter 2021 is going to be one that we won’t forget in a hurry.