Halloween forecast may require raincoats as costumes

A couple of days before Halloween, the Tallahassee area could see a chance of rain as a cold front approaches.

As of Tuesday, a front was over the Florida panhandle coastline, helping to bring showers and a few storms offshore and to some locations inland.

The surface map of the Southeast U.S. as of 11 a.m. Tuesday, Oct. 29. Source: WPC/NOAA

The front is expected to become a warm front and lift northward over the next 24+ hours as a storm system begins to take shape over the Southeast U.S. A dip in the jet stream will help set the stage for a surface low to develop Wednesday night into Thursday morning. A cold front will accompany the low, pushing eastward into the Big Bend of Florida.

As the front approaches, the two large-scale models (American GFS and the European) are in agreement with keeping rain chances in the forecast during the day and evening on Halloween. But there are some limitations.

As the front approaches, the trough of low pressure aloft will move northeastward into the Ohio River Valley, bringing the greatest lift along with it (see graphic below). For the Big Bend, this would leave less forcing for a soaker. The moisture profile will likely be above normal, enough to keep rain in the forecast. Both models essentially agree with the timing of the frontal passage (sometime early Friday morning).

The American GFS’ model output showing mid-level spin, which would indicate lift ahead of the spin, for Thursday evening. Source: College of DuPage

Early runs of the NAM 3-km model shows a line of showers and some storms moving into the Big Bend during the evening hours, around the time when many will be heading out trick-or-treating. This model should be taken with somewhat of a grain of salt this far out, but it does give an idea of what we could expect.

Rain totals? The ensemble run of the GFS isn’t being bullish on rain, but rain totals of under an inch are the likely scenarios in the Big Bend.

If you plan on taking the kiddos out for trick-or-treating Thursday evening, some rain gear wouldn’t be a bad idea to have on hand. Temperatures will likely be in the 70s with winds switching from the south to west.

Have a fun and safe Halloween!

Featured image credit: lobo235 / Flickr (https://flic.kr/p/6dduT) (Use under CC license)

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