The image above (courtesy TropicalTidbits) shows the 500mb pressure anomaly at 18k feet above the surface. Red colors show ridges of high pressure and blue colors show troughs of low pressure (dips in the jet stream).
- The image time-lapse above begins this morning (12z, or 7AM today) and runs through 1pm EST January 15th.
Bottom Line Up Front (BLUF):
- A deep trough (dip in the jet stream) will bleed very cold air into the Mid-Atlantic beginning on Thursday and likely sticking around through next weekend.
- The image below from the ECMWF EPS (European Ensemble Prediction System) shows the mean temperature anomalies (in Celsius) at 5k feet (850mb) between January 5th (Thursday) and Tuesday January 10th.
How long will the cold weather stick around?
The same model (image below) suggests that temperatures will begin to moderate on the east coast days 10 through 15 (Wednesday January 11th – Monday January 16th)
The Global Ensemble Forecast System agrees with the European (image courtesy WxBell):
- Second row first column shows the mean temperature anomaly the 5th and 6th of January
- Third row third column shows the cold air beginning to leave the East Coast (10th/11th of January)
- A second wave of cold may move back into the east before a final warm up.
And finally just how cold will it be?
The image above suggests highs may dip into the upper 20s to around freezing next weekend with low temperatures dipping into the middle teens in D.C.