Monday analysis

Steve Weiss, a long-time forecaster at the Storm Prediction Center (SPC) and really nice guy, gave a talk in the same session with me at the Severe Local Storms Conference in 2008 (for paper on this talk, click here). He pointed out that sometimes, the forecast confidence can actually decrease with time. That may be the case here, with models differing and a definite solution still difficult, with the event only 48 hours or so away.

Some of the models (UKMET, GFS, NOGAPS) seem to be forming the low farther south in the Gulf, keeping the bulk of the moisture south of the area, also. With the GFS, it’s almost like the main precip event north of I-20 will be associated with the cold front/upper-level impulse on Monday. That wouldn’t be a big event most likely, as the effect of cold air moving in would likely cause the precipitation to end as the cold air moves in, leaving only a brief period for changeover to snow Monday afternoon. The NOGAPS shows no precip north of MGM, and the UKMET shows the possibility of 1″ over central Alabama, with nothing in HSV.

The NAM shows more precipitation, and 850 mb temperatures not being cold enough for snow except for 3 or 4 hours. This could set up a band of 1-2″ somewhere in central Alabama, but that model also shows surface temperatures above freezing until after midnight in BHM. That would be a nice scenario…with snowfall Tuesday evening, maybe on grass, cars, and roofs, but not on the roads.

The European model has the low farther south like the GFS, and the Canadian model looks a little more aggressive, but still keeps the main moisture over south Alabama.

So, no major changes now. No significant evidence to indicate a major winter storm at any given location in Alabama right now, with the most likely scenario being a light dusting of snow, with maybe 1-2″ if things work out. It will be very cold Monday night and Tuesday, so even if no big snow accumulation occurs on the roads, some ice could form, making driving difficult Tuesday morning.

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