Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC
Issued by NWS Raleigh/Durham, NC
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420 FXUS62 KRAH 041901 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 300 PM EDT Tue Jun 4 2024 .SYNOPSIS... A series of mid-level disturbances will move east and interact with an unseasonably moist airmass over NC through Thursday. A pre- frontal trough and cold front will move across the area Thursday evening through early Friday. && .NEAR TERM /THROUGH TONIGHT/... As of 300 PM EDT Tuesday... A shortwave trough centered over the western NC this afternoon is expected to continue eastward through the afternoon and evening. As surface high pressure off the Mid-Atlantic coast continue to pump warm moist air into the region showers and storms will continue to develop over the next few hours. Expect storms to be pulse-type especially over the NW Piedmont region as the shortwave trough moves closer to the region. A second round is possible later tonight as an approaching MCV from the SW could re-develops closer to the region. While coverage is isolated this afternoon and evening, PoP chances slowly reduce, not completely diminish overnight into early Wednesday. WPC has maintained a marginal ERO for excessive rainfall across the much of the area with the greatest threat for flash flooding in urban/flood-prone areas. Lows overnight will range from mid to upper 60s. && .SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... As of 225 PM Tuesday... Upstream MCVs will continue to influence central NC`s sensible weather during this period as Bermuda high pressure remains in control. The first MCV, currently over central TN, will likely traverse central NC during the 1st half of the diurnal cycle. Isolated to widely scattered weak convection is possible as this feature moves through the area during what is otherwise poor diurnal timing. In the wake of the lead MCV, possible remnants of another MCV associated with the linear cluster over NE TX and lower MS Valley, could potentially move through the area during peak afternoon heating, with re-development of showers and storms from west to east across the area during the afternoon and evening. Deep layer shear increases slightly, but is still weak, and should mitigate the severe threat. Mean storm motion should also be higher than recent days, but given moist PWATs of 1.9-2.0", some localized flash flooding remains possible. Isolated to widely scattered showers/storms could linger overnight, especially with renewed lift from an elongated shortwave trough extending south from the mid- latitude cyclone over southern Ontario. Highs into the mid 80s to around 90 F, with some lower 80s possible over the NW Piedmont where the second round of convection could pop off earlier. Lows in the mid 60s to lower 70s with areas of stratus expected. && .LONG TERM /THURSDAY THROUGH MONDAY/... As of 330 AM Tuesday... By Thursday morning, an upper low will be over southwestern Ontario with a surface low a bit farther to the northeast. The surface cold front should extend southeast across the Great Lakes into Pennsylvania, then arc back to the southwest along the I-85/95 corridor. While some minimal changes were made to the area of likely shower coverage on Thursday, likely pops generally remain to the southeast of US-1. MUCAPE should be on the order of 1000-2000 J/kg, while effective bulk shear remains at or below 30 kt. Thursday also appears to be the warmest day out of the next seven, with west- southwesterly flow providing warm advection allowing highs to max out between the mid 80s and lower 90s. Although slight chance pops will continue from US-1 to the east Thursday evening, have continued the inherited dry forecast for Friday as the GEFS has finally come in line with other models showing all precipitation to the east of the region. Friday appears to be the day that noticeably drier air will arrive, with dewpoints dropping into the 50s (and upper 40s in the Triad). The dry forecast continues through Saturday into Sunday. Unfortunately, different runs of the GFS/ECMWF and their respective ensembles continue to flip-flop as to when the next front will approach the southeastern United States, so this part of the forecast has below normal confidence. For now, have slight chance pops Sunday night and chance pops everywhere Monday. The Thursday/Friday front won`t bring much change in high temperatures, with highs remaining in the 80s through the weekend. However, there will be some relief each night, with overnight lows in the lower 60s instead of the upper 60s. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... As of 205 PM Tuesday... Isolated showers and storms are beginning to develop across portions of the CWA, but ceilings are generally around 3k-4k ft over the Triad and 4k-7k elsewhere. Mostly VFR conditions are expected this afternoon and evening with the exception of periods when storms move over/near the terminals causing reduced vsby and ceilings. As the mid level disturbance moves across the region tonight and early morning, this could result in some flight restrictions early Wednesday morning ahead of the cold front. Outlook: Showers ans storms associated with a cold front that is expected to come through the region late Wednesday /Thursday will result in flight restrictions of MVFR or lower in some areas. VFR conditions are expected to return Friday through the weekend before another disturbance moves into the region early next week. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...MWS NEAR TERM...CA SHORT TERM...CBL LONG TERM...Green AVIATION...CA