Update (12:00pm) - The morning's rains have come through, and thankfully have been light enough to keep things from getting out of hand. Nevertheless, it was another quick 1/2-inch to an inch or so of rain for an already soggy ground.
Taking a look at the prospects for the afternoon...
This map covers both the upper and lower levels of the atmosphere, so we can see how they are both interacting. The moisture fetch from the first part of the day is still active, as indicated by all the little "X"s continuing to ride up along the flow and agitate shower/storm formation. The upper-level low center is lagging behind as it typically does. There are vorticity maxima (the Xs again) rotating along this as well. The idea here is that if the Sun breaks through between the initial line and the arrival of the low center, there will be additional instability generated to create storms. These storms will obviously carry downpours, but it is (as of now) on the low-side of likelihood that they rise to the level of causing flash flooding [still 1.5"- 2" of rain is a good ballpark threshold]. As always, there certainly can be spot areas that get flooding, especially if one of these potential downpours align with a traditionally vulnerable area. It is still a time for awareness, but it appears the prospects for flooding are lessening.
Good Sunday morning everyone.
Showers and steadier rains are moving through presently this morning, offering up another 0.2"-0.5" per hour rainfall rates. It's been a pretty wet week, so it won't take much to sog up the ground with any shower really. Expect a lot of standing water problems today as the rain will continue.
HAS - 48hour Rainfall Projection
The main axis of rain again comes through our region today. Judging from who got the most rain yesterday (in a line from Lawrence County, KY through Lawrence County, OH), these folks have the lowest threshhold for flash flooding at less than 2" of rain in a 6-hour period. The rest of us still close by at a little more than 2" in 3-6 hours. Keep a check of the rainfall totals map below to see how your area is doing. The National Weather Service will often issue a Flash Flood Warning when these threshholds are triggered or if they get reports on the ground of such flooding.
Atmosphere ripe for more action today...
The NAM model is representing a continued fetch of moisture up from the Gulf of Mexico and right across the tri-state area. Especially vulnerable will be that same corridor between Lawrence Co., KY and Lawrence Co., OH as they could see flooding triggered from a prolonged shower event as well as a spot downpour from a storm. The upper-level dynamics of today's weather is more impressive than what we've seen driving that of the previous several days:
GFS - 500mb Chart - Sunday Afternoon
Our "Bermuda High" continues to exert its influence, keeping that general influx of moisture-rich air in place. At the same time, an area lf low pressure in the upper level of the atmosphere moves east. That dip in the black lines at 500mb combined with the X's (Vorticity Maximums) that rotate through it indicate an enhancement of showers and storms during the day. This will be especially pronounced if we got any sunshine to slip in. This means the rain will arrive in two main sections: The burst we're getting now, and then the burst that develops during the afternoon.
As always, take stock of your present situation, and make a note of all flooding prone areas near you. All of those places are going to be stressed today, so be very careful when traveling. Low-water passes, viaducts, small streams, and culverts will be the first to go in a flash flooding event should one occur.
I will post updates to this blog post whenever time permits, but I also wanted to get out the tracking maps fairly soon. Check back frequently for any changes in watches/warnings and to keep tabs on both the location and amounts of rain that are around.