... A stalled frontal boundary over North Carolina may produce more showers and thunderstorms this afternoon. Afterward, high pressure will bring drier and hotter conditions for Wednesday and early Thursday. Another cold front should approach from the northwest by Thursday night into Friday.
NEAR TERM /THROUGH WEDNESDAY/... As of 1215 PM EDT Tuesday...
Confidence is high for hot and dry weather on Wednesday.
The earlier fog from this morning has dissipated, and temperatures for this afternoon have been nudged upward. While drier air enters from the northwest, a cold front will stall over North Carolina. The proximity of this boundary combined with heat and moisture will yield another round of showers and thunderstorms along the Virginia and North Carolina border. Heavy downpours will be possible in the stronger storms. Convection should wane after sunset.
High pressure will move over the Mid Atlantic tonight, but lingering surface moisture could trigger more patchy fog in parts of the Piedmont and along the New River. With a northwest flow at the surface and aloft, the resultant downsloping combined with plentiful sunshine should give hotter conditions on Wednesday with mid 90s expected east of the Blue Ridge and most of the mountains getting well into the 80s. Heat indices could approach 100 degrees east of a line from Lynchburg to Reidsville.
SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... As of 200 PM EDT Tuesday...
...Hot And Drier For Thursday With Front Still Expected Late Thursday Into Friday...
The highlight of the short term forecast will be the front that is expected to arrive very late Thursday, and traverse across the region Friday. The overall impact for this front continues to look less prominent for our area as arrival time looks to be after sunset Thursday when diurnal heating will be gone. Guidance points to a decent QLCS system forming along the frontal boundary for the Ohio Valley that will move eastward, but the loss of heating should happen before it can finish its trip across WV to really impact us.
As the front moves across the area Thursday night into Friday, expect some lose coverage in showers and eventually thunderstorm for the afternoon. The likeliest place for more organized convection will be near and south of the VA state line with the front pressing southward, serving as a focal point for lift. Obviously alterations in timing could happen depending on how fast the front can get through.
Temperatures remain above normal for this part of the forecast period.
Forecast confidence is moderate.
LONG TERM /SATURDAY THROUGH TUESDAY/... As of 200 PM EDT Tuesday...
...Monitoring multiple features for enhanced precipitation chances...
The long term period should generally be characterized by somewhat cooler temperatures than those that will be experienced this week. Most of this is owed to the persistence presence of troughing from Saturday onward. Consistent northwest flow aloft will only back to westerly by Tuesday as the base of the trough approaches. Needless to say, a consistent pattern of northwest flow is favorable for one or more cold frontal passages, and the long term pattern does not look to disappoint.
On Saturday, the cold front that will have led to precipitation chances in the previous day is expected to be near the southern portion of our forecast area. It is plausible that with convective enhancement, the front will have cleared the CWA entirely by Saturday, but deterministic guidance currently supports a scenario where at least scattered convection will be plausible over our North Carolina counties. The northern end of the forecast area will likely experience dry and cooler conditions, with highs failing to reach the 90s.
From Sunday onwards, the next heightened potential for showers and storms diverges greatly among the main deterministic models. The GFS begins to sag the next in the parade of fronts toward the area, which would mean heightened rain chances over the northern half of the CWA Sunday into Sunday night, with rain chances sagging southward the next day. As of now, the ECMWF is over 24 hours slower with this frontal feature, with rain chances approaching the northern part of the area Monday night and Tuesday looking like the main event from a precipitation standpoint. We will continue to monitor model trends and anticipate convergence toward the true solution as the event draws closer. For now, rain remains plausible within the CWA anytime between Sunday and Tuesday. Both models do agree, at least, that the upper-level trough and surface cold fronts should keep temperatures at or below normal throughout the long term period.