UPDATE: A Winter Storm Watch is up for central and southern Virginia, with 5 inches of snow or more possible for Charlottesville. Three to 8 inches are possible across the watch area, including the Virginia Eastern Shore. Farther north, in Maryland, there are no watches or warnings, just a Hazardous Weather Outlook.
This morning we have a pretty good demonstration of why forecasters at the National Weather Service decline to make snow accumulation predictions more than 36 hours in advance of the event.
Early this week, as AccuWeather.com and FootsForecast.org began chirping about a 6-to-12-inch snowfall (or more) in Baltimore by Friday and Saturday, the NWS was content to post 60 percent chances for some sort of snow on the weekend. It was too far out to be confident about such things, they insisted.
The federal forecasters took some heat from WeatherBlog readers for their reticence. After all, Accuweather's bloggers were all aflutter about the storm. Mr. Foot acknowledged his team's stance was "bold," but stuck with it.
Now the computer models - which all agreed on Monday that we'd see a pounding by the weekend - now all agree that the storm track will send the low across the Carolinas and out to sea.
The NWS this morning predicts no more than a 30 percent chance for snow in the Baltimore region Friday night and Saturday, with North Carolina and Southern Virginia looking at the best chances for snow. Accumulation forecasts, if any, should be out this afternoon.
Maryland may not get off scot-free. "Accumulating snow will still be possible, especially the southern zones," Sterling says in its morning forecast discussion. "But at the moment, [moisture] appears insufficient for more than 1 to 3 inches in southern portions of the forecast area ... Some light snow may approach the Washington, D.C. metro ... but any accumulations should remain light."
AccuWeather.com began shifting its snow track south (map) on Wednesday, with Southern Maryland and the Lower eastern Shore still in the bullseye. "MeteoMadness" blogger Henry Margusity has scaled back his prognostications, but this morning still manages to make it sound scary for the urban corridor: "I know folks in Baltimore-Washington are watching this real closely. You're going to be pretty close to the heavy snow area." And then, "It could be a case where DC gets maybe 4-5 and Baltimore gets 1 to 3. It's a real tough call."
Mr. Foot, too has had to back down. "The polar vortex is in charge," he concedes. "We will have to remain patient for a fantastic February."
UPDATE: Mr. Foot's team of student meteorologists has been watching developments. One Sparrows Point 10th grader has authored an update suggesting the storm track has moved north again, a bit. See below:
SNOW THREAT UPDATE
Ryan K. Grade 10 (01/28/10: 12:15PM)
So the waiting game continues here in Central Maryland to see what happens with the previously expected snow event. Things went away, but the trends definitely point to one thing: this is coming back north. Precip is back into the area, and if this occurs, say only 50-75 miles more north which is definitely possible, we could get a decent hit. At this point, the amount of snow only looks to be 1-2 inches, but as I said in last nights e-mail things could change (and that has already begun to occur.) All of the afternoon models so far have pointed to that farther north solution, leaving DC in a good area for snow and our area on the northern fringe.
The most aggressive model at this point is the Canadian model which at its latest run gave the area 4-6” of snow. This model has led the models on their trek northward, and in the 12-19/20 blizzard, this model led the way. Also, the ECMWF (European model) which has been the best model according to statistics, trended north last night. In my opinion, if this trend is one that continues this afternoon with the 1PM run, then we will have a legitimate risk for a nice snow event.
Thoughts at this point:
---Currently model runs depict a 1-3’’ snowfall in our area
---The storm is currently trending north and certainly has the potential to continue that trend, giving us the formidable snow threat
---The storm’s timing is steadily moving back so at this point an overnight Friday into Saturday threat would be the time when the storm (if things come to fruition) arrives.
Things to watch: The way the media outlets present the storm and the way they present the storm, as well as the emails we send out. If you want to do basic observations, simply check out the way the storm is moving on radar and nowcast a bit.
Indicator of threat:
This map (12z GFS snow output) shows how close we are to the good snows, the 1-2 is here now, but the slightest shift, 25-50 miles puts us in 3-4’’ with any more than that giving us a 6’’ snowstorm. The chance is definitely there, so stay alert.
Next Update: This afternoon and a possible frequent updates tonight and tomorrow. Will have a snowfall map done as well to be sent out.