Next Blast of Cold Weather arrives Thursday, How long will it last?

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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.

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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)

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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.

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And finally just how cold will it be? 

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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. 


More Beneficial Rainfall Headed for the Washington Area

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The image above shows our next two waves of rainfall moving through the Washington Area. The image is courtesy TropicalTidbits and the forecast model is the NAM, or North American Model (a short-range model).

The time-lapse loop (future-cast image above) begins at 01z (Zulu, or 8PM this evening) and runs through 00z Wednesday (7pm Tuesday EST).

Bottom Line Up Front (BLUF):  

  • Heaviest rain should remain south and east of D.C. on Monday with a lull in activity on Monday evening across our area.
  • A wave of moderate to potentially heavy rainfall is likely across the immediate Washington Area during the day on Tuesday.

How much rainfall could fall across the Mid-Atlantic?

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Most locations should pick up around a half-inch of rain with some locations across southern Maryland picking upwards of 1 to possibly 2″ of rain.