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December 9, 2009

Next up: coastal flooding, colder temps, "brief" snow

 Loch Raven Dam

Woke up this morning to the sound of heavy rain on the roof and, soon after, a forecast of more rain, and more snow chances for late Saturday into Sunday. Nothing dull about this autumn's weather so far.

Loch Raven DamSo I drove out to Loch Raven Dam (above, and left), where the water was roaring over the top and flooding portions of the valley below. (Many thanks to the very nice Baltimore County police officer who did not give me a parking ticket.) The Jones Falls (below) was over its banks, too.

More immediately, we're looking for minor coastal flooding as southerly winds and heavy runoff push high tides as much as two feet above the predicted levels. Then there will be gale-force winds, a chance for thunderstorms (and more rain) in parts of the state this afternoon as a cold front passes behind the storm. And once the front passes, we'll see plummeting temperatures ahead of the weekend snow.

Where to start on this storm, which has clobbered much of the country with rain, wind and snow.?

The rain. We measured about 1.5 inches on the WeatherDeck in Cockeysville overnight. BWI airport reported 1.71 inches, which is almost exactly what we had in our gauge here at The Sun, North Calvert and Centre streets. It fell at rates exceeding 1.1 inch an hour at times. 

For the month, the airport has seen almost 4 inches of rain, well above the 3.35-inch average for the entire month at BWI. The total for 2009 is now about 51.5 inches. That makes this the fourth-wettest year in the last 20 years, after:

2003:  62.66 inches

1996:  58.31 inches

1989:  51.88 inches

Many locations on the Eastern Shore reported well over 2 inches of rain overnight. Here are the totals from CoCoRaHS.  Closer to Baltimore, the rain totals ranged from 1.08 inches in Ellicott City, to 1.76 inches in Sverna Park, to 1.96 inches in North East, up in Cecil County.Jones Falls

As the cold front approaches today, we will remain on the warm side of this storm, with persistent winds from the south pushing water up the Chesapeake Bay and holding it there. That is going to mean minor coastal flooding along the western shore. The NWS has issued a Coastal Flood Advisory from Harford to St. Mary's counties, forecasting high tides two feet above normal levels. (Annapolis tide graph below.)

A Gale Warning is also up today for the lower tital Potomac River and lower portions of the Chesapeake Bay.

Then there's the snow. Forecasters say once the cold front blows through this afternoon, temperatures will drop as "modified" arctic air pours in. The overnight low forecast for Baltimore on Friday night into Saturday morning is 21 degrees. A quick-moving disturbance will pass to our south, strengthening a developing coastal low. There's a 30- to 40-percent chance that will bring us "accumulating snow" late on Saturday into Sunday. No depth predictions yet, but the storm is described as "brief."

Beyond the weekend, forecasters see more arctic air arriving early next week.

NOAA Tides Online

(SUN PHOTOS by Frank Roylance)

Posted by Frank Roylance at 11:23 AM | | Comments (3)
Categories: Forecasts


Nothing is going to happen Saturday. We might see snow changing to rain on Sunday.

The position of the surface high for this event will be to far to the east and will change our winds to the southeast as the storm (if it forms) approaches.

We might get accumulation in the AM but the temps and rain in the PM will turn it in to another slushfest by Sunday afternoon.

I'd love to see a good snow, but I doubt it will happen this weekend.

There was a cold front this afternoon?

FR: Yes. The barometer bottomed out between 3 and 4 p.m. EST, and winds were gusting to 35 mph at BWI. That looks like about the time it went through. BGE had about 12,000 outages, most in Anne Arundel County. Cold, dry air is moving in today. You'll notice it soon.

You folks in Baltimore should consider moving to Rochester, NY. We have NO snow here today!!! All day, I have been harassing my sister who lives a bit North of Cockeysville, about the lack of snow here. Even though I have lived in Rochester for 30 years, the worst snow storm that I experienced was the "Blizzard of '66", when I was living in Towson.

Sure, we've got high taxes in Upstate NY, but you've got more snow!!!

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About Frank Roylance
This site is the Maryland Weather archive. The current Maryland Weather blog can be found here.
Frank Roylance is a reporter for The Baltimore Sun. He came to Baltimore from New Bedford, Mass. in 1980 to join the old Evening Sun. He moved to the morning Sun when the papers merged in 1992, and has spent most of his time since covering science, including astronomy and the weather. One of The Baltimore Sun's first online Web logs, the Weather Blog debuted in October 2004. In June 2006 Frank also began writing comments on local weather and stargazing for The Baltimore Sun's print Weather Page. Frank also answers readers’ weather queries for the newspaper and the blog. Frank Roylance retired in October 2011. Maryland Weather is now being updated by members of The Baltimore Sun staff

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