Wednesday, December 21, 2011

Latest forecast update through Christmas Day

In our last blog post on Sunday, we noted computer models were having a very tough time figuring out the weather pattern over the Mid-South for the latter part of the week, including Christmas weekend, and that the forecast was subject to change as the week progressed. Now, 72 hours later, models have come into agreement on one potential storm system during this period for Thursday, but unfortunately there still remains some disagreement and uncertainty concerning the weather on Saturday, Christmas Eve, especially. A closer look at the latest possibilities for the holiday weekend is coming up.

First, model agreement and confidence for the next 24 to 48 hours has considerably increased as the next storm system to impact the area will soon be developing and moving through the area. After a warm and rainy Tuesday, much cooler air has filtered into the region following the passage of a cold front overnight. However, this front will be stalling later today just to our southeast, as low pressure develops over Louisiana tonight. This low pressure area will track northeastward along the stalled boundary Thursday which should spread more rain into the Mid-South. Rain should begin by morning and persist much of the day, tapering off during the late afternoon. It will be a much colder rain than what we experienced Tuesday, with temperatures likely to hold in the upper 40s to near 50 degrees during the day. Rainfall amounts look to be rather heavy, around an inch (see image below). You’ll want to have the rain gear ready again for Thursday and allow for extra commute time, especially during the morning rush.

GFS model rain totals from 6am-6pm Thursday, with 1” totals indicated across the Memphis metro .
As the low pressure area departs Thursday evening, drier conditions will once again return as weak high pressure begins to take hold. Friday should be a dry day, but low-level clouds will likely linger with temperatures remaining on the cool side, in the upper 40s. Uncertainty comes back into play for Saturday, as models continue to struggle over a potential storm system developing and passing to our south during this period. Models appear to finally be coming into agreement over the actual presence of a low pressure system, but continue to differ on its exact track and placement of any associated precipitation, which will impact whether the metro area sees any rainfall.

At this time, there still appears to be at least a low chance for rain, with the greatest opportunity likely to occur around Saturday night. Rainfall, should it occur, would be on the light side, and temperatures appear as if they will remain warm enough to keep rain as the only possible precipitation type. No matter the impacts it brings to our area, it looks to move off to the east Christmas Day, which means drying conditions and clearing skies should occur, with temperatures remaining near the seasonal average, in the lower 50s.
GFS weather depiction for Christmas Day at Noon. Any light rain Sat night will have exited to the east, with the best chances for precipitation nationally across the Pacific Northwest and light snow possible in the Great Lakes region. Much of the nation is likely to have a dry Christmas.
Of course, this means those looking for a white Christmas are likely to be disappointed again this year, but this should be no surprise given our area’s history. Measureable snow has only fallen once on Christmas Day itself, in 1913 (3.5” total), though snow flurries have fallen on several other years, including last year. Snow has been on the ground Christmas Day from previous storms several times, most recently in 2004, with the greatest snow depth recorded in 1963 when a whopping 10” was still on the ground! That white Christmas followed one of the biggest snowstorms in Memphis history on December 22, which also resulted in the coldest low temperature on record for the city, a bone-chilling -13F on Christmas Eve morning!  Video below is taken from public domain footage of a news story about the record snow just before Christmas 1963.

With confidence still rather low on Saturday’s weather, and the forecast subject to change, you’ll want to continue to stay with MemphisWeather.Net for the very latest updates.  We'll keep you updated via the MWN Forecast and Facebook and Twitter.

--Kevin Terry, MemphisWeather.Net

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1 comment:

Dave said...

The snow is late here in the london, 10 Cel. by night!

visit me?