Pity the poor weather forecasters. This storm continues to vex them, just as those that have come before this winter have done.

Officially, they're calling for rain and snow at BWI-Marshall, beginning after midnight Wednesday morning, becoming all rain after noon as temperatures rise from the freezing mark to the upper 30s. Snow may mix back in after dark, changing to all snow after midnight Thursday morning. 

But even just 36 hours out, forecasters are still puzzling over exactly where the storm will go, exactly who will get rain, who will get snow, and where the slop between will fall. And the computer models still can't give them consistent answers.

The storm itself is gathering on the Gulf Coast tonight, sweeping up plenty of moisture to send north and east, along with milder temperatures.

"Unfortunately, the model guidance starts to diverge through this time frame," forecasters admit in this afternoon's forecast discussion from Sterling. "That places significant uncertainty in system evolution, during a winter season where that seems to be the norm."

A 42-degree high on Tuesday, followed by increasing cloud cover to put a sort of blanket over the region - holding in some of the daytime solar heating, would seem to argue against overnight temperatures cold enough to sustain "a big snowstorm," they reason.

So they lean toward a rain/snow mix beginning around dawn Wednesday. And not a lot of precipitation at that, despite the storm's Gulf origins.

They're talking about rain to the south and east, snow to the north and west, and a mix in between. At the same time, they confess, "[We] have low confidence on who will get what ...Maximum temperatures Wednesday should be above freezing most areas, which would cut [snow-to-water] ratios and make accumulations more problematic anyway."

Bottom line here: Take an umbrella. Wear sensible shoes.

What's everyone else saying?

Foot's Forecast still deals with the uncertainty by laying out a range of possibilities. And they still like Scenario A: "Some snow would be possible for areas west of I-95 in western Maryland and western Virginia. Areas from Southern Maryland to the upper Eastern Shore would have a mix of rain and snow or just rain, with all rain for the Atlantic beaches. Liquid precipitation totals for the I-95 corridor could exceed one inch in some places, however light snowfall amounts would be confined to a possible changeover to snow on the backside of the system."

Eric the Red, a professional forecaster from Baltimore offers: "My best guess: Snow and sleet will arrive in the predawn hours on Weds, and changeover to mixed precip or cold rain along the I-95 corridor, while moderate to heavy snow falls farther west.  As the day progresses, precip will change back to all snow from west to east, with some accumulations likely. Precip will taper off Weds night.  This does not look like a whopper, but will nevertheless have enough precip with it that snow totals - if the pcp stays all snow - would tally 4 to 8".  But before you start thinking about the impending 4-8" snowfall, know that the odds are stacked against this thing staying all snow."

And here's AccuWeather.com: "There are several factors influencing this storm, mostly that weigh in against heavy snow in the major I-95 cities from New York southward through Washington/Baltimore. However, some areas inland of the coast will get clobbered with snow from the storm."

Their rain/slop/snow map (above) shows a tightly banded stretch right through Central Maryland. Easy to see there why such a small shift in storm tracks could make a big difference in what happens here.

My bet? A very cold, rainy day for Baltimore on Wednesday, with lots of slush to the north and west.

(SUN PHOTO: Amy Davis, January 1994)