Archive for March, 2011

According to the National Weather Service:

THE FLOOD WARNING CONTINUES FOR THE DELAWARE RIVER AT RIEGELSVILLE.  AT 8:30 PM FRIDAY, THE STAGE WAS 24.8 FEET.  FLOOD STAGE IS 22.0 FEET.  MINOR FLOODING IS OCCURRING AND MINOR FLOODING IS FORECAST. THE RIVER WILL CONTINUE RISING TO NEAR 25.0 FEET JUST AFTER MIDNIGHT TOMORROW, AND WILL FALL BELOW FLOOD STAGE TOMORROW EVENING.

Though there have been breaches of the towpath into the canal above Riegelsville and water over the road in Upper Black Eddy, there is no serious flooding occurring in Nockamixon Township, and so our EMA will not be activated for this flooding event. We do continue to monitor weather conditions for any important changes.

FLOOD WARNING NOW IN EFFECT UNTIL 430 AM EST FRIDAY

* AT 430 PM EST BANDS OF HEAVY RAIN WERE DEVELOPING NORTHWARD IN THE WARNING AREA OF EASTERN PENNSYLVANIA…FAR NORTHERN SECTIONS OF NEW JERSEY AND DELAWARE AND EXTREME NORTHEAST MARYLAND. THIS RAIN WILL EVENTUALLY CAUSE FLOODING OF AT LEAST SOME SMALL STREAMS IN THE WARNING AREA TONIGHT.

* AT 4 PM…ONE TO 2 INCHES OF RAIN HAD FALLEN ACROSS MUCH OF THE WARNING AREA. ANOTHER 1 TO 2.5 INCHES IS EXPECTED BETWEEN NOW AND 4 AM FRIDAY WITH ISOLATED STORM TOTALS NEAR 4 INCHES EXPECTED IN NORTHEAST PENNSYLVANIA AND FAR NORTHERN NEW JERSEY. THIS RAIN IS RUNNING OFF RAPIDLY DUE TO SATURATED GROUND FROM SUNDAY NIGHTS HEAVY RAIN.

A FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR HAS BEEN REPORTED. ALL INTERESTED PARTIES SHOULD TAKE NECESSARY PRECAUTIONS IMMEDIATELY.

PRECAUTIONARY/PREPAREDNESS ACTIONS…

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SOME SMALL CREEKS AND STREAMS…HIGHWAYS AND UNDERPASSES. ADDITIONALLY…COUNTRY ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS…STREAMS AND OTHER LOW LYING AREAS ARE SUBJECT TO FLOODING.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE DANGERS OF FLOODING. IF FLOODING IS OBSERVED ACT QUICKLY. MOVE UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

TO REPORT FLOODING…HAVE THE NEAREST LAW ENFORCEMENT AGENCY RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE.

TODAY’S RAINFALL SO FAR HAS ALREADY BROKEN THE RECORD DAILY TOTAL IN ALLENTOWN WITH 1.31 INCHES. PLEASE REMAIN ALERT AND MONITOR NEWS AND WEATHER SOURCES FOR FURTHER UPDATES.

According to the National Weather Service, a flood watch remains in effect through Friday morning:

* RAIN WILL OVERSPREAD THE REGION THIS MORNING…AND CONTINUE THROUGHOUT THE DAY AND INTO TONIGHT. THE HEAVIEST RAIN IS EXPECTED TO FALL THIS AFTERNOON INTO TONIGHT. STORM TOTAL RAINFALL AMOUNTS SHOULD AVERAGE TWO TO THREE INCHES WITH LOCALIZED HIGHER AMOUNTS POSSIBLE…WITH THE HIGHEST AMOUNTS OVER NORTHERN AND WESTERN PORTIONS OF THE AREA.

* THE ESTIMATED RAINFALL AMOUNTS WILL CAUSE FLOODING OF LOW LYING AREAS…AS WELL AS CAUSE SMALLER STREAMS AND CREEKS TO RISE OUT OF THEIR BANKS. THE RUNOFF SHOULD ALSO CAUSE FLOODING ALONG MAIN STEM RIVERS. THE PASSAIC RIVER IS THE MOST VULNERABLE DUE TO ONGOING FLOODING. THE RARITAN…DELAWARE AND SCHUYLKILL RIVERS ALSO ARE VULNERABLE. MANY RIVERS AND STREAMS REMAIN AT HIGHER THAN NORMAL LEVELS AND WILL NOT RETURN TO NORMAL FLOW BEFORE THIS NEXT ROUND OF HEAVY RAIN.

PRECAUTIONARY/PREPAREDNESS ACTIONS…

A FLOOD WATCH MEANS THERE IS A POTENTIAL FOR ADDITIONAL FLOODING BASED ON CURRENT FORECASTS.

YOU SHOULD MONITOR LATER FORECASTS AND BE ALERT FOR FLOOD WARNINGS. THOSE LIVING IN AREAS PRONE TO FLOODING SHOULD BE PREPARED TO TAKE ACTION SHOULD FLOODING DEVELOP. PLEASE MAKE ALL THE NECESSARY PREPARATIONS TODAY. IF YOU EXPERIENCED FLOODING WITH THE LAST EVENT THE COURSE OF LEAST REGRET WOULD BE TO PREPARE FOR IT AGAIN. BECAUSE OF THE RECENT HEAVY RAIN THE LIKELIHOOD EXISTS FOR THIS UPCOMING EVENT TO AFFECT EVEN MORE WATERWAYS AND CAUSE POSSIBLY HIGHER CRESTS.

The NWS estimate of flood crest has dropped overnight to about 26 feet at Riegelsville. You can find that gauge and other conditions monitors here. Our EMA is monitoring the situation and the team has been elevated to Alert Status. We are likely to activate on Friday if forecasts remain steady. Please watch this site for further information.

According to the National Weather Service in Mt. Holly, NJ, the Delaware River has already moved past alert stage of 18 feet and is expected to exceed flood stage of 22 feet this afternoon, 3/8/11. Levels at the measuring gauge at the Riegelsville Bridge are expected to crest at 23.2 feet by tonight, causing minor flooding.

Unfortunately, a second significant rain event is headed our way on Thursday. Currently, the expectation is for 2.42 inches of new rain on the entire headwaters area of the Delaware River, down to about an inch and a half in our area, as shown on the map below.

 

March 10 rain estimate map

Estimated precipitation from late-week event

Since it’s what falls north of us that creates river rises here, this is obviously not a good thing, since the river will already be high. We urge all residents and businesses with interests along the river to carefully monitor this situation.

The Nockamixon Emergency Management Agency has begun monitoring developments in an approaching weather scenario that involves the interaction of several systems, which could result in a prolonged heavy rain event. Several scenarios are possible, depending on how these systems interact, with one possible outcome being the deposit of 2-4 inches of rain on already saturated or frozen ground in the Delaware River Valley.

Potential Precipitation Map

Projected precipitation potentials from one standard weather model

This, combined with the still substantial snow pack remaining in the Pocono Mountains and areas to the north that drain into the Delaware Basin, could conceivably create anything from localized flash flooding to possible significant rises on the river itself.

Current snow pack in the Poconos and other areas near the Delaware's headwaters

Current snow pack in the Poconos and other areas near the Delaware's headwaters

The systems are still too far out to tell specifically where the precipitation will fall, but those with interests along or near the river should begin paying attention to weather forecasts and river gauges. We recommend bookmarking our Weather Conditions Monitors page for a collection of many such sites covering our region, and staying tuned to regional radio, TV and Internet news sources.

It’s also a good idea to check the battery in your NOAA All Hazards Weather Radio for this season of potential flooding and our official entry into severe storm season (here’s a link about preparing for severe storms in Illinois, but the information is accurate pretty much anywhere severe weather strikes).

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