Smitty's attempt to educate and to a much lesser extent, entertain, about all facets of life; but primarily the meteorological and the climatological aspects of the earth sciences.
And the title is not referring to the cold front that will blast through our region sometime when "Joy To The World" is being sung at midnight mass tonight! Just ahead of the passing of the strong cold front, warm air will invade our region on some gusty SSW winds...look at these temp anomalies...
Wind gusts well over 30 mph will be occurring around midnight; first to help scour the low level cold air, then briefly spike temps to near 60°F prior to the temps crashing back to near 40°F by morning. This is a very well mixed air mass, so Christmas Day should be relatively mild with temps near 50°F for maxes. And a visit from the sun is guaranteed! Haven't had many of those sightings over the last 3 weeks! Here is a close-up map centered on Harrisburg indicating wind gusts well over the 30 knot threshold...so make sure those air filled Santas and Snowmen are tightly secured. There will be quite the pressure gradient accompanied with this frontal passage, so gusty conditions are also guaranteed!
But the real purpose of this posting is to quickly discuss the potential of winter weather arriving in spades early next week. There will be several wrinkles in quite a strong jet as arctic air bleeds and presses south and east into the Mid-Atlantic region. Below is the jet stream map for next Tuesday. Note the direct discharge of arctic air from...well...the arctic and then the baroclinic zone setting up very close to southern PA! (Location of the jet). In addition, the upper level divergence with the fast jet streaks should lead to several bouts of snowfall for us in the Monday-Wednesday time frame. The timing of each little wrinkle is simply to difficult at this time parameter!
The map below shows the moisture available for precipitation...precipitable water along with the sea level pressures. Note the low pressure over TN-MS-AL and that low, although weak should track across northern VA and then up towards Nova Scotia. This is the arctic boundary where just to the NW of the purple colors, very cold and dry air will begin to claim. A nice overrunning event should occur here across PA! The Euro has been pretty consistent in its solution over the last several runs.
Once this system passes, the model is sensing snow on the ground as some very cold anomalies are being modeled! Brrrr...you will hear about the polar vortex next week once again I do believe! Look at the UP of Michigan. That is from deep fresh snow pack from lake effect with this arctic air invasion.
The 850 mb temps are quite cold and high pressure will rule the roost for several days after the New Year! But don't get to used to that as many more jet disturbances look poised to wiggle along this arctic boundary and more snowfall is likely into the first part of January.
So that is my Christmas Week Synopsis and I'm sticking with it! And with the wind this evening, I believe you'll hear to wind chimes, trash cans, rafters, etc...but play this video below so you can hear The Bells On Christmas Day!
Merry Christmas y'all...and as always...THANKS for reading!
Smitty
AA: Windy this evening to get rid of this rain/wet/mess. Then a few clearer and drier days prior to some potentially nasty winter-like weather early next week. Then quite cold around New Years Day...and a bit beyond! Merry Christmas my friend!
