Jet stream dips way down into the southeastern United States, picking up moisture from the Gulf of Mexico and the Atlantic Ocean – leading to a possible significant rain event Tuesday night into Wednesday.
Here’s a map of the jet stream – the green and yellow colors are the highest wind speeds.
Notice how the jet stream streamlines go all the way from western Canada to the Gulf of Mexico to Maine – that’s what they call a high amplitude trough – a big, deep wave in the jet stream.
See the highest winds are where the wind arrows are pointing northward. That usually means that the trough is not going to deepen much more. That would keep the storm to our north.
But look at the map for winds and temperature at 850mb (about one mile up).
See that the warmer temperatures in orange are being pushed up the east coast. That will bring lots of moisture and the warm air will rise (as warm air wants to do) and that upward velocity will condense out lots of that moisture – perhaps right over us.
There are other considerations as well – the Weather Service Office in NYC http://forecast.weather.gov/product.php?site=NWS&issuedby=OKX&product=AFD&format=CI&version=1&glossary=1&highlight=off
has more details.
We’ll see if the storm pans out as planned, but now you’ll see the atmospheric magic behind the weather this week.
The maps are from the NAM model, found at the UNISYS Weather site at