... High pressure was centered along the Mid-Atlantic coast this afternoon. This feature will move off the coast tonight. A cold front will move from the Great Lakes into the Ohio Valley today, associated with showers and thunderstorms to our northwest. This front will stall across the northern Mid- Atlantic Saturday, introducing a chance for showers and thunderstorms to our region. A tropical system is expected to impact areas mainly south of our region Sunday.
NEAR TERM /THROUGH SATURDAY/... As of 710 PM EDT Friday...
A line of thunderstorms moving across the Ohio Valley today disintegrated as they approached the mountains late this afternoon. The debris clouds from these storms are moving over the northern half of the area (north of Highway 460) this evening. There is another complex of storms currently moving over Wilmington Ohio this evening. If these storms hold together, they will bring some rain to the Greenbrier Valley during the early morning hours Saturday. We have tweaked PoPs up to likely for western Greenbrier. No other major changes made to tonight's forecast.
As of 115 PM EDT Friday...
Continued fair weather is expected through the evening. Thunderstorms over the Ohio Valley may impact areas north of I-64 tonight.
High pressure over the forecast area is promoting clear/dry weather conditions. Some scattered high based cumulus this afternoon, but with no vertical development due to the lack of CAPE. Cirrus also expected to filter in later this afternoon from an upstream MCS over OH/KY.
Return southwesterly flow is expected to develop on the back side of the high pressure this afternoon and evening with the best moisture advection into the Ohio Valley, west of the mountains, and ahead of an approaching frontal boundary entering the Ohio Valley from the northwest. Dew points still on the lower side locally, in the mid to upper 50s along with no CAPE/instability, expecting the upstream MCS to continue to weaken as it moves east with only the potential for the thunderstorm outflow to reach our southeast WV counties and the VA Highlands, north of I-64 toward midnight or so. Kept a chance of some showers/storms mainly north of I-64 overnight for any remnant activity associated with the diminishing MCS.
Model guidance develops a second MCS in Indiana/Ohio late tonight and into early Saturday morning. Expecting this to also mostly remain out of the area, but still kept low POPs in for areas along and north of a line from Bluefield/Roanoke/Lynchburg and north for tomorrow as the remnants of this MCS could fire a few isolated storms along its outflow late Saturday morning/early afternoon.
Temperatures today are expected to top-out 5 to 10 degrees warmer than yesterday with 80s in the mountains and lower 90s in the piedmont, aided by warm air advection ahead of the approaching front, and return southwest flow around the departing high. This will also translate to warmer temperatures tonight with lows mainly in the 60s. Temperatures for Saturday will be a couple degrees warmer again as flow becomes westerly with a lee trough in the east. Could see some decent downsloping east of the Blue Ridge which could really drive temperatures upward through the afternoon. Dewpoints will gradually increase over the next 24 hours.
SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... As of 110 PM EDT Friday...
A true Summertime weekend ahead with increasing heat, humidity, and chances for scattered storms....
We officially start Summer Sunday June 20th at 11:32 pm and it sure will feel like it out there. Tropical moisture will be firmly intact to our south with a cold frontal boundary sitting just off to our north and west. These two features we'll be the main focal points for showers and storms to round out the weekend into early next week. With that said, uncertainty still remains with the models in regards to our tropical system coming up from the Gulf and how much of an influence it has on our region along with it's interaction with the front.
Current 12z guidance shows more of a southerly solution with the track of the incumbent tropical system keeping it mostly confined to South Carolina and eastern North Carolina during the Sunday afternoon and Monday morning timeframe. This would limit us in the precipitation department with most of our activity as a result of the front nearby and any tropical influence skimming the North Carolina mountains/foothills. A little shift in track could be the difference for any further impacts the further north the system comes and it's overall interaction with the nearby front.
Speaking of that front, it looks to remain stalled just north of the region late Saturday night into Sunday and Monday. Flow out ahead of the boundary will remain relatively flat out of the west to southwest leading to downslope flow east of the Blue Ridge. With downsloping in play and a tropical system scooting by to the south plentiful mid to high level clouds should be in place to limit instability across the area. For now, kept PoPs in the chance range especially along and west of the Blue Ridge as well as north of the I-64 corridor where better lift can be found near the front. The combination of cloud cover and increasing precipitation chances lead to a little less heat Sunday afternoon. Highs will be in the low to mid 80s in the west with highs close to 90 out east where downsloping flow remains.
Better chances for showers and storms move in Monday as a deepening upper level trough from the Upper Midwest and our cold front from the Ohio River Valley push in. Rich low level moisture will remain in place out ahead of this boundary as our tropical system from the Gulf departs somewhere off the Atlantic Coast Monday morning into Monday afternoon. Once again, uncertainty remains on this system as it has yet to make landfall along the Gulf Coast and the overall placement of our front set to move in late Monday into Tuesday. Storm coverage across the region per current model guidance looks to be widely scattered ,but could be limited to a degree with increased cloud coverage across the region. Chance PoPs will remain in the forecast for all areas Monday with likely PoPs along and west of the Blue Ridge where higher confidence remains for convective development.
Monday we actually warm back up with tropical air overhead. Highs will range from the mid to upper 80s in the west with upper 80s and low 90s out east. Overnight lows will be quite soupy as well on both Saturday and Sunday nights with most locations hovering around 70 degrees.
Confidence is moderate in the long term based upon uncertainty with our tropical system to the south and our front giving us a squeeze play to the north. Higher confidence in shower and thunderstorm activity heading into the Monday and Tuesday timeframe.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 130 PM EDT Friday...
Unsettled start of the workweek with passage of cold front, followed by cooler and drier midweek with moderating temperature into the end of the workweek...
The longwave trough digging over the Midwest and Great Lakes will push a cold front southeast through our region Tuesday into Tuesday night. A wave of low pressure may develop along the frontal boundary Tuesday night into Wednesday. This may slow the exit of the front from our region with an isolated shower possible across the southeastern part of the area into early Wednesday. High pressure builds southeast into our region Wednesday into Wednesday night. The high center will slide east Thursday and push into the Atlantic ocean Thursday night into Friday.
Moderate confidence in the Long Term Forecast especially behind the front with noticeably cooler and drier air by mid week, then moderating temperatures into the end of week.