Pre-Christmas Storms, Then Cold

An all new edition of the ABC 33/40 Weather Xtreme video is available in the player below. You can subscribe to the Weather Xtreme video on iTunes by clicking here.

WINTER ARRIVES: Welcome winter. The solstice is today at 11:47 a.m. when the sun is directly over the Tropic of Capricorn, meaning today we have our lowest sun angle of the year, and the “shortest day” of the year, in terms of the number of daylight hours. After today, we see an increasing amount of sunlight.

THE MOST WONDERFUL TIME OF THE YEAR: And, this will be a wonderful day. Following a sub-freezing morning, we enjoy a sunny day today with a high up in the mid 50s, right where we belong in late December.

PRE-CHRISTMAS STORM: Our pre-Christmas storm will indeed develop, and will bring a variety of inclement weather to much of the nation. And, now that we are within 84 hours of the event, we can make a forecast. For snow fans, it is a disappointment here with the initial surface low running from near Lubbock, Texas to Chicago.

This is the best pattern for a White Christmas in Alabama, with a moderate El Nino cranking out storm systems every three days, and a strongly negative AO/NAO (Arctic Oscillation/North Atlantic Oscillation). Yes, of course, this setup has happened many times, but I can’t recall it happening the week before Christmas in my long tenure here. Usually the lows run from the Gulf of Mexico, and then up the Atlantic coast, much like the one we saw late last week. And, with the negative AO helping to push cold air down here, it opens the door up for all kinds of winter weather mischief.

But, with the northern track, the big snow this week will be from the plains of Colorado, through much of Kansas, Nebraska, Iowa, Minnesota, and northern Illinois. Seems like Omaha and Des Moines are in the bullseye for heavy snow.

HERE AT HOME: We will be in the warm sector of the cyclone, and we will deal with rain and thunderstorms on Christmas Eve. Some rain could break out as early as Wednesday afternoon with warm air advection, but the main round of precipitation will hold off until Thursday. SPC has outlined a slight risk of severe weather for states to the west on Wednesday, but they have chosen not to include Alabama in an outlook Thursday due to the question of instability. It will be a battle between cold air damming, and cool/stable air to the east, and the dynamics and warm/moist air surge with the storm system to the northwest. Dynamics will support strong to severe storms, but thermodynamics are somewhat marginal. We will watch closely this week as the storm unfolds. The main window for stronger storms seems to be from about 12:00 noon until 10:00 p.m. Thursday. Sure seems like the best chance of strong/severe storms will be over the western half of the state.

CHRISTMAS CHILL: In the wake of the rain and storms, sharply colder air will move into Alabama Christmas Day. As has been the case in recent weeks, GFS MOS products are too warm. Friday looks like a day with temperatures falling into the low 40s, perhaps even the 30s by late afternoon with a brisk north wind. Then, the cold air hangs around for Saturday and Sunday with highs in the 40s Saturday. We will most likely have a hard time getting out of the 30s on Sunday based on projected low level thickness values.

ONE THING TO WATCH: In this kind of ENSO setup, we usually see energy transferring from the main inland low to a new low forming on the South Atlantic coast. The global models aren’t too bullish on this setup, but something like that might offer a surprise or two. Remember, this is a challenging pattern and the forecast is always subject to change.

NEXT WEEK AND BEYOND: The pre-New Year’s storm shows up around the middle of next week with a cold rain likely for the Deep South, and snow to the north. Yet another one comes up around January 1. You get the idea… a storm system about every three to four days into the New Year, which offers a challenging series of days for us in the weather business. But, we will just take them one at a time.

WEATHER BRAINS: Don’t forget you can listen to our weekly 30 minute netcast anytime on the web, or on iTunes. This is the show all about weather featuring many familiar voices, including our meteorologists here at ABC 33/40. You can even listen here on the blog; look for the player on the top left. We will record a new show tonight featuring Dr. Joe Schaefer, retiring head of the Storm Prediction Center. The new episode will be posted around 11:00 p.m. CST.

FOLLOW ALONG: Here are our weather team Twitter accounts….

Look for the next Weather Xtreme video here by 3:30 this afternoon… enjoy the day!

Category: Uncategorized