Tuesday, September 4, 2018

Gordon's effects on the Mid-South

As Tropical Storm (maybe Hurricane, depending on when you read this) Gordon heads towards the central Gulf Coast for a landfall likely to occur somewhere along the MS or AL coastline, many of you have expressed interest in how it will affect our weather.

Forecast track and intensity

Latest forecast track of Gordon from the National Hurricane Center (NHC).
The track forecast has been spot on and relatively easy for several days (in fact, almost a week ago, the European model depicted a landfall near New Orleans for the middle of this week, before the Hurricane Center started publicizing the possibility of the storm). A strong mid and upper level ridge of high pressure over the Mid-Atlantic and Ohio Valley is basically steering the storm northwest. That trend will continue through landfall tonight and into Wednesday and Thursday, though a slower forward speed is expected after landfall. While Gordon may briefly reach hurricane strength before landfall tonight, it will quickly diminish in strength once it encounters land.

Primary threats remain to our south

The primary threats with the storm will be hurricane force wind in a small area near the center where it makes landfall, storm surge for the MS/AL/west FL panhandle coastlines, and copious amounts of rain across along and just to the right of its track into the Lower Mississippi Valley and western Mid-South. Along that path, rainfall amounts of up to 6-10"+ will be likely, resulting in flash flooding in some areas. The most recent rainfall potential graphic is shown below.

Potential for heavy rain and flash flooding will remain to our south the next couple of days. (NHC via WPC)

Mid-South rainfall

The heaviest and steadiest rain will miss the greater Memphis area it appears, though we will start to see scattered showers and thunderstorms Wednesday afternoon as the center moves across south-central MS. The trend will continue Wednesday night as it moves into southern AR, though with fewer thunderstorms. The Storm Prediction Center believes any strong wind or isolated tornadoes common in landfalling tropical systems will remain to our south.

The SPC severe weather outlook for Wednesday indicates the potential for severe storms should remain to our south. (SPC)

By Thursday, as the center of the remnants of Gordon move through western or central AR, we will be in a position to see continued chances of showers and thunderstorms. It is worth pointing out that no prolonged heavy rains are expected, but some localized areas could get a downpour, especially in thunderstorm cells. Overall, an inch of rain or so can't be ruled out over the next couple of days but most places should stay under a half inch.

NWS/WPC rainfall forecast through Thursday evening shows 1"+ rainfall amounts to our south.

Rain chances looks to dip a bit Friday into Saturday as the storm moves well to our west, though with ta humid and moist airmass left behind, a chance of thunderstorms, especially in the afternoons can't be ruled out. By late in the weekend, it appears a frontal system could slowly approach, resulting in increased rain chances as it moves into the humid air.

Mid-South wind impacts

As for wind, the strongest sustained wind in our area will likely be Wednesday afternoon when the storm is still at its strongest and in close enough proximity to generate easterly gusts to 25 mph or so. That is expected to calm down to 10-15 mph Wednesday night and Thursday as Gordon falls apart. No major power or tree issues are expected, just a fresh breeze from a semi-unusual direction tomorrow!

We encourage you to check out the MWN Forecast for the latest information via the mobile app or our website, and stick to us on Facebook and Twitter for hyper-local updates as needed. All links are below. Hopefully, the best news from Gordon is increased cloud cover and some showers that knock the edge off the heat of late!

Erik Proseus
MWN Meteorologist

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