(click to enlarge)
STORM STAYING SOUTH?
Winter won’t quit, and all eyes are on the storm gathering strength to the west and south. On the map above it is the feature extending as a dashed orange line from Minnesota down to fronts in Arkansas. Ordinarily the part in Arkansas would develop and speed north or northeast up into the Great Lakes, however we are stuck in a “blocking pattern,” which means storms run into a wall, and get squashed south and east. Once the storm gets off the coast it will “bomb out,” and there are already warnings for Washington DC. However the question is: Will the storm head up the coast and clobber Boston (and we little people north of Boston?)
The important feature on the map is actually the storm out to sea from us, stalled south of Nova Scotia. It is actually the same storm that was discussed here on February 28, in “The Color Of Slush.” https://sunriseswansong.wordpress.com/2013/02/28/the-color-of-slush/ which was trapped by the “blocking pattern,” which shows as the high pressure at the top right of the map.
During a blocking pattern that storm will just sit there, rotating and gobbling up various features that pass to its south, sometimes moving east but then backing back west, and driving people in New England slowly crazy, for by March people start yearning for spring. People hunger for a southwest wind, and a day, just a single day, when temperatures get balmy, however when a storm stalls out over the Atlantic to our east we get day after day of north winds, until it seems like it will never end.
As the storm sits out there it absorbs passing features, which lose their distinct warm fronts and cold fronts and become occlusions that rotate right around the low, like spokes in a wheel, and come in off the ocean and down on us from the north. They are so stirred into the batter of the storm they sometimes don’t even rate a dashed orange line on the weather map, and are basically the left-over shreds of old storms called “junk” by some weathermen, but they continue to exist as an impulse, and sometimes gather a bit of moisture off the ocean that manages to interact with a bit of arctic air sucked in from the northwest.
That happened yesterday, when the forecast was for “flurries.” I never trust a forecast for “flurries” this time of year, especially in a blocking pattern. Yesterday our “flurry” turned into a steady snow, which grew heavy for long enough to coat everything with a half inch, and briefly grew blinding as the wind picked up and roared. The children at our childcare are so toughened by the long winter they barely paused their sledding, but I glowered at the sky, because I didn’t want to shovel.
To my relief the flakes again grew sparse, and went back to wandering about as loners, but never ceased, so I could never completely relax, for I’m old and cynical, for I have seen a forecast of “flurries” be six inches of snow, in my time. I got up in the night to be sure no sneaky snow had whitened the streets, and was glad to see stars and the half moon rising, as the north wind sighed.
The good thing about such persistent north winds is that they often shunt storms to our south out to sea. That is what I am hoping happens to the approaching storm. When the GFS computer created an imaginary blizzard for Boston, last night, I winced. I’ve had enough of shoveling.
I suppose the storm could swerve north. In such cases the new storm joins the old one, and stalls out to sea to our east, and the north winds go on and on. However in other cases the southern storm tugs the stalled storm to our east away, and they can even head off across the Atlantic towards Europe swinging around each other like a bola.
Guess which scenario I am hoping for.