NOAA, National Weather Service Middle Atlantic River Forecast Center Briefing 11am Tuesday, April 29, 2014

Key Message Heavy rain forecast through Wednesday in the Middle Atlantic Region. Minor River Flooding has already begun in isolated spots, but the majority of river flooding will be Wednesday and Thursday. Flooding could last into the weekend in spots. Majority of flooding will be minor. Two points forecast to reach moderate flooding: Millstone River at Blackwells Mills, New Jersey and Neshaminy Creek at Langhorne, Pennsylvania.

Timing of rain & flooding Rain began yesterday and should continue through Wednesday night. River rises will begin first in the smaller streams and creeks. It will take a longer time to get the larger rivers rising. Crests expected from Tuesday to Friday depending on the location.

Rain already on the ground This is the amount of rain that has occurred in our area since Monday morning. The lighter blue shades are the heaviest amounts, in the James River basin, of over 1.50”.

This is the amount of rain forecast to occur from 8am today (Tuesday) to 8am Wednesday. The dark purple shades are the heaviest amounts over 1.75”.

This is the amount of rain forecast to occur from 8am Wednesday to 8am Thursday. The bright red shades are the heaviest amounts over 3”.

This is the amount of rain forecast to occur from 8am Thursday to 8am Friday. This is the final bits of rain as the storm moves out. Rainfall will be light, under a half inch.

This is the grand total rainfall forecast from 8am today (Tuesday) to 8am Friday. The lightest red shades are the heaviest amounts over 3” over the lower Susquehanna River basin and the middle Potomac River Basin.

River Forecasts Moderate Flooding is forecast for the Millstone River at Blackwells Mills, NJ and the Neshaminy Creek at Langhorne, PA. Minor flooding is forecast for several points along the: – Assunpink Creek – Aughwick Creek – Brandywine Creek – Conococheague Creek – Conodoguinet Creek – Conostoga River – James River – Monocacy River – North Branch Rancocas Creek – Opequon Creek – Passaic River – Potomac River – Raritan River – Rivanna River – Rockaway River – Schuylkill River – Shenandoah River – Sherman Creek – Swatara Creek – Yellow Breeches Creek NOTE: These forecasts were valid as of 11am April 29. River forecasts may be updated often during this event as we get a better idea where exactly the heavy rain will fall. Please check for your most up-to-date river forecast at gov gov

Flood Outlook Significant flooding cannot be ruled out this week in the area colored in yellow.

MARFC Status MARFC began 24 hour operations this morning at 6:30 am. MARFC will remain open until the threat of flooding has ended. MARFC hydrologists and hydrometeorologists will be updating our rain and river forecasts throughout this event.

Remember MARFC graphics & info are focused on river flooding may not show your entire flood threat. See for info from your local NWS Weather Forecast Office about flash flooding, coastal flooding, etc..

Flood Inundation Maps Excellent resource to understand your flood risk. Shows coverage and depth of flood waters. Can be used to plan evacuation routes & travel. Available at for these points: – Chenango River at Greene & Chenango Forks. – Delaware River at: Montague, Matamoras/Port Jervis, Belvidere, Easton, Frenchtown, New Hope/Lambertville, Riegelsville, Stockton & Trenton – Passaic River at: Chatham, Clifton (Dundee Dam), Little Falls & Millington. – Pequannock River at Riverdale. – Pompton River at Pompton Plains. – Saddle River at Lodi, NJ – Susquehanna River at: Harrisburg, Bainbridge, Binghamton, Conklin, Owego, Unadilla, Vestal & Windsor – Unadilla River at Rockdale, NY – Upper Saddle River at Saddle, NJ. – West Branch Susquehanna River at Jersey Shore, PA

Flood Safety If flooding occurs, go to higher ground. Road beds may be washed out under flood waters. NEVER drive through flooded roadways. Do not camp or park your vehicle along streams particularly during threatening conditions. Be especially cautious at night when it is harder to recognize flood dangers. Monitor for your river forecast. Look for frequent updates. Realize the uncertainty in river forecasts.

Need more info? Contact your local NWS Weather Forecast Office – Binghamton, NY – Blacksburg, VA – Mt Holly, NJ – State College, PA – New York City, NY – Sterling, VA – Wakefield, VA MARFC at

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Next MARFC Briefing Unless forecasts change dramatically this afternoon, our next briefing will be sent out midday Wednesday.