Friday, September 23, 2011

A beautiful start to the weekend, but one that will likely end wet

It was about as perfect of a start to fall as you could want it across the Mid-South! Temperatures today have been in the 70s with crystal clear sunny skies after the passing cold front last night that brought just a few showers, with trace to very light rainfall amounts at most in the metro area. For those who wanted more substantial rain, however, it appears to be in the offing before the weekend is over thanks to an unusually strong and large system in the Upper Mississippi River Valley that will help push another cold front into our region.

Prior to that, tonight and Saturday will continue the great weather - perfect for the opening of the Mid-South Fair, the Memphis Tigers homecoming game, and any other outdoor events being planned. After lows in the 50s tonight, Saturday will see temperatures return to near the 80-degree mark.

Meanwhile, to our north, a large area of low pressure at the upper-levels of the atmosphere is taking shape over the western Great Lakes and will strengthen over the weekend, while slowly moving west into the Upper Mississippi River Valley (see image below). This unseasonably strong and large upper-level low will help to drag a surface cold front closer, and eventually through, the Mid-South region. Clouds will first begin to increase on Saturday night, but it will remain dry. The same will be true for the first half of Sunday, but by the afternoon, an area of rain and thunderstorms will develop and begin to push in from the northwest along and just ahead of the front. This rain will likely impact the Memphis metro for much of the evening and night, as the cold front slowly pushes east. Rain will then begin to move out Monday morning as the front clears the area.
GFS Model forecast for Sunday night shows the strong, large upper-level (18,000 feet) low pressure system near the Iowa/Illinois border that will help push a cold front and rainfall into the Mid-South
Rainfall amounts could be moderate to heavy across the metro area, with computer models and National Weather Service guidance indicating between one-half to as much as 2 inches of rainfall possible (see image below). Any thunderstorms could lead to isolated higher amounts. While flash flooding will be unlikely, the rainfall may make for travel difficulties Sunday night and Monday morning, and may also put a significant damper on outdoor activities planned for Sunday evening. At this time, severe weather is not expected though.
NWS Total Precipitation through Monday evening, indicating 1-2” of rainfall in the metro area, most of which would fall on Sunday night
Drier air and clearing skies will begin to filter into the Mid-South later Monday into Tuesday as the upper level low to our north and cold front to our east begin to push further away, bringing a return to mild, early-fall weather. At this point, the remainder of the work week looks dry, with mostly sunny to partly cloudy skies, and high temperatures back in the 80s.

Stay tuned to MemphisWeather.Net over the weekend for the latest on the increasing rain chances.

--Kevin Terry,

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