CW3E AR Update: 10 December 2024 East Coast Outlook

December 10, 2024

Click here for a pdf of this information.

Strong East Coast AR Forecast to Bring Significant Precipitation and Snowmelt to the Northeast

  • A strong atmospheric river is forecast to develop over the southeastern US and transport significant tropical moisture up the East Coast into the Mid-Atlantic and New England, with the highest IVT > 1600 kg m-1 s-1.
  • GEFS and EPS ensemble models combined probabilities of IVT show high confidence of a period of IVT > 1000 kg m-1 s-1 over Providence, RI, with 15 combined ensemble members forecasting max IVT > 1750 1600 kg m-1 s-1.
  • This AR is associated with anomalously high PWAT over the Northeast, with 3-week percentile rank PWAT values of 99.5 percent rank. An AR with IVT 1600 kg m-1 s-1 would rank as the 14th strongest AR over the area since 1959 and be the highest non-tropical IVT since 18 Dec 2023, a major flooding event over the Northeast.
  • The NWS WPC has forecast 72-hour precipitation totals > 1.5 inch over much of the eastern US, with localized regions of 3-5 inches of precipitation over the Southeast, Mid-Atlantic, and New England. WPC also issued marginal and slight excessive rainfall outlooks over these areas of elevated precipitation between 10-12 Dec.
  • Snow depths are forecast to reduce dramatically during this event in association with warm air temperatures and significant rainfall, leading to substantial river level rises and significant flooding along rivers in New England.
  • The NWS Northeast RFC has highlighted the possibility of significant river flooding over much of the Northeast. Wind gust are forecast to exceed 40-50 mph for coastal locations between New York City and northern Maine.

Click images to see loops of GFS IVT and IWV forecasts

Valid 0600 UTC 10 December 2024 – 2100 UTC 12 December 2024

Summary provided by S. Bartlett, J. Cordeira, and M. Steen; 10 December 2024

To sign up for email alerts when CW3E post new AR updates click here.

*Outlook products are considered experimental

For any unfamiliar terms, please refer to the American Meteorological Society Glossary.