As darkness descends upon parts of the central and southern US this Halloween, a southeastward marching cold front will spread chills down the spines of any poor soul unfortunate enough to be caught in its path. Millions of Americans, from Texas to Maine, will be confronted by the cold front’s wicked wrath.
The cold front will be commanded by a growing upper-level disturbance that will eventually spread eerie conditions across nearly all of the contiguous US by late week The dark force behind the inclement weather will draw strength from the warm, moist Gulf of Mexico air mass flowing just ahead of its arrival from the Gulf Coast to the southern shores of Lake Michigan. Impacts northwest of a line from Topeka to Milwaukee will be light, but further southeast there will indubitably be fright.
Showers and thunderstorms will increasingly develop ahead of the cold front Tuesday and put a damper on early Halloween festivities from Milwaukee and Chicago southwest to Kansas City and Tulsa. The jet stream will be strongest over Illinois, Indiana, and Missouri, where up to 2″ of rain will fall through the overnight hours. Hallowing winds will spread chills as they climb the Ozark mountains of eastern Oklahoma and western Arkansas Tuesday night, resulting in additional areas of 2″ rainfall. The rain will clear in time for Halloween, but the damp chill will keep the uneasiness in place.
The core of the system will swipe at the swamps of eastern Texas and Louisiana Wednesday. It is here where the clash between air masses will yield the most intense horrors. An unstable atmosphere will be forced to rise against the incoming cold front and parent upper-level trough. Simultaneously, winds above the surface will wail more intensely with height. Eastern Texas and western Louisiana will be at the right entrance to the region of the jet stream where these winds will be most intense. This is where the atmosphere will be dynamically stretched upward the fastest, where rain will pound the hardest, where winds will screech the loudest, and where damage will be the greatest. A slight chance of hail will accompany some of the stronger storms, but the shrieking winds will be the most potent threat.
The torrential rain is the last thing Texas needs. As discussed in the most recent Sunday Storm, parts of Texas have already recorded their wettest October and autumn on record. The saturated soils will have little defense against the heavy rainfall, which could approach 2″ in spots.
While severe thunderstorms ravage Texas and Louisiana Halloween night, millions of Americans from Mississippi to Maine must confront a different terror manifest as flooding rains. The cold front will trigger heavy showers that will soil plans from the lower Mississippi and Ohio Valleys northeast to the shores of Lake Erie and Ontario, the Green Mountains, and northern Maine. Baton Rouge, Vicksburg, Little Rock, Memphis, Louisville, Cleveland, Pittsburgh, Buffalo, and Burlington are just a handful of the cities to be overcome by the dark forces aloft.
Showers will be heaviest along and south of the Ohio River, closer to the tropical moisture and the dynamic source of the Halloween trick. Up to 4″ of rain between Wednesday afternoon and Thursday morning will race down hillsides and overwhelm streams and rivers from southwestern Ohio to the mouth of the Mississippi River. Anyone brave enough to confront the vile weather may find themselves surrounded by water. Further northeast in eastern Ohio and the inland Northeast, showers will likely be intermittent Wednesday, but the rain will last through Thursday.
The cold front will continue to spread heavy rain eastward throughout the week. The rain will reach the Northeast coast by Friday. Fortunately, this will be too late to spoil any Halloween plans.