Updated below (most recent 2:00pm)
It's the middle of the week... almost there!
(although for folks that know that oodles of hours of outdoor Mother's Day labor lies ahead...perhaps the anticipation is slightly different ;-)
Our weather-map today features a typical post-frontal picture. The idea is typically for cooler weather and returning sunshine, but just like we talked about yesterday, my sneaking suspicion may be confirmed:
|NMM - Streamlines - Wednesday PM||NMM - Vorticity - Wednesday PM||NMM - Precipitation - Wednesday PM|
I decided to throw in the map of vorticity (a measure of the extra 'spin' in the atmosphere beyond that of the normal rotation of the Earth). There's something I want you to take from each map. The 'streamlines' map shows wind-flow direct from Lake Michigan (moisture) right to the WV mountains (elevation). The vorticity map shows a strong lobe of positive vorticity advancing to the Ohio River. Putting the two elements together, you have support for the map on the right. The moisture-rich wind-flow pushing up the mountains will be forced to condense and precipitate only there, much like the forcing of a cold front. (if you notice this same area has negative vorticity over it, but it doesn't matter because the force of elevational "orographic" lifting over-rides it). By the same token, right at the push of positive vorticity advection we see a few showers spotting up by the Ohio river on the right-hand map. So there are two different forcings at work, each responsible for trying to get rain to fall on an otherwise supposedly "improving" day. We'll have to see if this actually comes to fruition, though I think at a minimum we'll have a period in the afternoon when clouds fill back in if they clear out earlier. This stands in addition to the spotty showers that are dribbling into Eastern Kentucky this morning-- not a whole lot of action there, just enough to get in a few swipes with the windshield wipers. So, a little 'issue' early, and another one late.
Looking ahead to Thursday, the air does end up drying out, and high pressure rides in to keep things that way for a few days in a row (yay). Here's what HPC has it looking like:
|HPC - Thursday|
As this area of high pressure approaches, it will keep the steady inflow of northerly winds out ahead of it (air moves clockwise around high pressure systems, so when we're to the west of one, we're getting winds that blow from north to south). This will keep the afternoons cool, but pleasantly so. Perhaps the only real issue is going to be the overnight lows:
|Max Temps - Thursday||Max Temps - Friday||Max Temps - Saturday|
|Min Temps - Thursday AM
||Min Temps - Friday AM||Min Temps - Saturday AM|
So, just about everyone will like that kind of weather-- in the afternoon. As far as the morning goes, well, hopefully the kids that still have school haven't had their coats quite packed away yet. We also still have that nagging question of frost, certainly more of a reality nearer to the Tygart river valley and the Canaan valley of northern West Virginia (around the Elkins temperature value). Typically the coldest weather we get locally might get within about 2-4 degrees of Elkins, but in the most isolated of hollers. Early Friday morning poses the biggest risk, but so far indications still put us just out of reach from the frost. Better during the week rather than on the weekend of Mother's Day-- if you're sticking the new plants in the ground Saturday, you should be good to go!
Update (2:00pm) - Well whaddya know :-) Check out the radars below. Definitely looks like a combination of mountain elevated showers with a pinch of cold-air-aloft instability showers in southern Ohio. Since that cold air is lowering freezing levels (the altitude at which the temperature is 32°F), I wonder if we can scare up some small hail or graupel with those pimply showers sprouting up just across the Ohio river.
|Regional Radar/Satellite with Warnings Tracking||
|Temperatures||HD Doppler Radar||Estimated Rainfall||Active Warnings|
|Click For Larger||Click For Interactive Radar||Click For Larger||Click For Larger|
Have a great day everyone!