|Dew Point:||37.6°F (3.1°C)|
|Wind:||From the SE at 5.8 MPH|
|Wind Chill:||33°F (1°C)|
|Sea Level Pressure:||26.62" (901.4 mb)|
Chance Light RainHigh: 45 Low: 34
Partly SunnyHigh: 43 Low: 26
Mostly SunnyHigh: 40 Low: 30
SunnyHigh: 49 Low: 39
Light Rain LikelyHigh: 49 Low: 39
A chance of rain. Cloudy. High near 45, with temperatures falling to around 39 in the afternoon. Northwest wind around 18 mph. Chance of precipitation is 50%. New rainfall amounts less than a tenth of an inch possible.
Rain likely before 10pm, then a chance of rain and patchy drizzle and patchy fog between 10pm and 1am, then patchy drizzle and patchy fog and a slight chance of rain between 1am and 5am. Cloudy, with a low around 34. West wind 10 to 17 mph, with gusts as high as 28 mph. Chance of precipitation is 60%. New rainfall amounts less than a tenth of an inch possible.
Partly sunny, with a high near 43. Northwest wind 13 to 18 mph, with gusts as high as 29 mph.
Partly cloudy, with a low around 26. Northwest wind 9 to 14 mph, with gusts as high as 28 mph.
Mostly sunny, with a high near 40. Northwest wind 5 to 8 mph.
Mostly clear, with a low around 30.
Sunny, with a high near 49.
Mostly cloudy, with a low around 39.
Rain likely. Cloudy, with a high near 49. Chance of precipitation is 60%.
... Low will slide off to the east tonight, with cooler air moving in behind the system for the beginning of next week. High pressure mid week. Another system due late next week.
NEAR TERM /THROUGH MONDAY/... As of 1255 PM Sunday...
Subsidence inversion will keep an abundance of low stratus in place heading into the evening hours. Meanwhile, areas of light rain or drizzle will become confined to the mountains. Above 4000 feet, this will tend to transition to light freezing rain/drizzle. I have elected to handle this in the HWO for now, as coverage and impacts are in question overnight. Some clearing will work in from the west tonight, but likely not making it east of the Ohio River until late.
There is some uncertainty whether low stratus holds into Monday across the mountains with the NAM locking in moisture beneath the inversion actually for most of the area. This solution was largely discounted outside of the mountains, with some nod to the model in the high terrain. There is some weak, mainly orographically enhanced, lift persisting Monday in the mountains which may keep some patchy drizzle/freezing drizzle going but confidence is low on this panning out.
A s/w trof and associated cold front will drop into the area Monday afternoon. Models indicate there will be scant moisture except beneath the persisting inversion, mainly across northern counties. I kept with previous forecaster thinking with some low pops across the northern mountains, taking the form of light snow showers or drizzle/freezing drizzle.
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... As of 200 PM Sunday...
Favorable upslope flow continues to squeeze out drizzle/freezing drizzle Monday night with shallow moisture lapping up against the western slopes of the mountains. A couple flakes of snow are possible in the mix with the top of the saturated layer clipping the bottom of the DGZ. Regardless of crystal growth, a stout subsidence inversion aloft suppresses any development outside of the upslopes thus limiting impacts.
High pressure builds from the NW starting early Tuesday and erodes low- level moisture, gradually clearing out and precipitation and low- level stratocu through the day. The high pressure center drifts SEward from the Mitten state into western PA by Tuesday evening, into the Mid- Atlantic by early Wednesday. This turns low-level winds southerly and in turn increases warm air advection and baroclinicity especially in the Ohio Valley to round out the period. High clouds associated with the next weather- maker begin streaming in from the SW Wednesday as temperatures reach into the 40's in the mountains, 50's across the lowlands, around 10 degrees above normal for this time of year.
LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... As of 215 PM Sunday...
Attention turns to an approaching trough ejecting from the Rockies during the middle of the week. Trekking eastward into the Plains, the northern and southern streams come into phase, amplifying the unified trough, and extending a surface pressure trough extending from central Canada down into the lower Mississippi Valley.
Ahead of the trough, deep southerly flow allows warm/moist advection to continue Wednesday night with PWAT increasing to near 1" by the end of Thursday in our area. Sky coverage will continue to increase and cloud bases will lower through Thursday. Temperatures do again reach the 40's/50's Thursday afternoon with ample sky coverage likely canceling out additional warm advection.
Meanwhile, further upstream, strong jet-level winds migrate from the upstream to the downstream portion of the trough, spurring cyclogenesis along the elongated pressure trough under favorable jet dynamics. The resulting low will track from from WSW to ENE across the eastern CONUS as the parent trough axis pivots negatively in a similar manner. Expect the first rain showers associated with warm advection to enter the area from the SW by mid- to late-Thursday with showers continuing through Friday night as the low sails past. 1-2" of rain are possible across the area with this system.
Synoptic-scale model differences are relatively slight between major long-range models; the GFS yields a somewhat deeper system tracking directly through our Ohio Valley counties while the ECMWF paints a slightly more progressive picture with a low tracking up the lee of the Appalachians. The main impacts here are that a more progressive solution tends to a) rain out more over the eastern upslope areas of the eastern mountains and downslope/dry into the lowlands and b) bring in cooler conditions faster in the wake of the system, Friday night into Saturday.
Decided to expand/extend PoPs Saturday with models agreeing on strong northwesterly flow and cold air advection, and the assumption of left-over moisture in the low-levels, as is often the case in this locale during the cool season. Thus Saturday would bring widespread rain/snow/mix showers (mostly rain in the lowlands, snow in the mountains during the day) depending on how efficiently cold air makes it into the area.