Happy TGIF! We are headed into the last weekend of summer (fall arrives next Sat. at 9:49 AM)....but this weekend will feel plenty like fall. The forecast is a little bit of a headache for this weekend, so let's jump in.
We'll jump ahead in the charts to Sunday at 7PM. Above is the 500 mb chart (upper air chart...about 18,000 ft), where we keep an eye out for those "mid-level disturbances" you may sometimes here us talk about. We find a rather elongated disturbance running from Texas, northeast across Arkansas, and into our area (look for shades of light blue/green/yellow...indicating "vorticity", or spin). Ahead of this disturbance, southwest flow aloft will keep moist air from the Gulf of Mexico streaming toward our region, and this disturbance will keep considerable cloud cover over our area for most of the weekend. This will keep daytime highs in the mid 70's, about 5-10 degrees below normal for this time of year. Lows will run in the mid 50's.
As that disturbance moves east across the deep south, it will lead to some rain chances for the southern half of the area. Right now, it looks like the best chances arrive later Sunday night/early Monday....however, models have been trending a little quicker with this system, something to watch. Rain chances may have to be bumped to an earlier time frame if this trend continues, and if this system tracks farther north, it may lead to a showery Sunday. With models not yet seeming to have a good handle on this system, it makes at least the Sunday forecast a little uncertain.
Just as that mid-level disturbance begins to wind down, a fairly potent cold front will be knocking on our door from the west on Monday. This will lead to our best chance of rain area wide, as seen on the Monday 7PM chart below.
With rain chances ending by Tuesday morning, the end result should be slightly heavier rain across the southern half of the area...with totals running from around 0.25" north, to possibly around 1" south. These numbers could certainly change with upcoming model runs though.
After the rain moves out, the bigger story with this system is going to be the arrival of a brief, but significant shot of cooler air, as seen on this 850 mb chart for 7AM Tuesday (lower-level chart, about 5,000 ft....used to analyze temperature trends):
Those "cooler" colors in shades of green/blue represent a batch of cooler air that should ultimately lead to highs in the upper 60's/near 70 on Tuesday, and lows Wednesday morning in the mid 40's! If that's too cool for you, this little dip in the jet stream will swing on through and we'll at least get closer to normal for the end of the week.
By the end of the week, it looks like another cold front will be sliding closer to the region, with perhaps another chance of rain. With that still nearly a week away, we'll save the details for that system for the next update over the weekend. Hope you enjoy these pleasant temperatures this weekend!
After the rain moves out, the bigger story with this system is going to be the arrival of a brief, but significant shot of cooler air, as seen on this 850 mb chart for 7AM Tuesday (lower-level chart, about 5,000 ft....used to analyze temperature trends):
No comments:
Post a Comment