Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC
Issued by NWS Raleigh/Durham, NC
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267 FXUS62 KRAH 200458 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 100 AM EDT Fri Sep 20 2024 .SYNOPSIS... An upper level trough along the East Coast will shift slowly eastward and offshore through Saturday morning, as a weak surface high pressure ridge extends from New England down through the central Carolinas. An upper level disturbance will track southeast through the Mid Atlantic region late Saturday through Saturday night. An upper level high pressure ridge will then build in from Texas across the Gulf and Southeast states through early next week. && .NEAR TERM /THROUGH TONIGHT/... As of 944 PM Thursday... The upper trough axis has shifted offshore this evening, with primarily nwly flow over central NC. A residual embedded mid-level impulse continues to generate some weak convection in the NC/VA mountains/foothills. While most of this activity should wane and stay out of our area, an isolated shower may trickle into the Triad over the next hour or so. Otherwise, expect dry conditions overnight with lows in the lower to mid 60s. More concerning tonight is the potential for areas of dense fog. A few sites across the central to northern Piedmont have shown lower visibility from fog in the past hour or so. Given clear conditions tonight and residual anomalous moisture over the area, we`ll likely see dense fog increase in coverage over much of the Piedmont especially closer to sunrise (~08 to 12Z). Will have to monitor overnight, but a dense fog advisory may be needed for portions of the Piedmont. && .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... As of 105 PM Thursday... Aloft, the trough off the mid-Atlantic coast will continue to shift ewd over the Atlantic, allowing high pressure to ridge enewd into the area. A lobe of vorticity in the upper levels will swing sewd through central NC Fri morn/aft, while a trailing mid-level disturbance follows Fri aft/eve. At the surface, a low will continue to meander off the northern mid-Atlantic/New England Coast Fri/Fri night, while high pressure ridges swd through central NC. Some lower dewpoint air should push into the far northeast portions of central NC as the high ridges in. While widespread convection is not anticipated, if showers do develop, the best chance would be over the western Piedmont during the morn/aft with the passage of the vort max aloft, and over the northeast Piedmont/northern Coastal Plain during the aft/eve, generally along the dewpoint gradient as the high ridges swd. The NAM does have some MUCAPE in the 500-1000 J/Kg range Fri morn through the eve, thus an isolated storm or two is still possible if/where convection occurs. Highs should generally range from around 80 degrees NE to mid 80s south, with lows in the upper 50s to mid 60s expected. && .LONG TERM /SATURDAY THROUGH THURSDAY/... As of 325 PM Thursday... Saturday morning, surface high pressure will be centered over eastern Canada with a pressure ridge extending all the way to the Gulf Coast. A weak front will move across the area Saturday night. Am not terribly impressed by the depth of the moisture with the front, but there are too many models, deterministic and ensembles, to keep a dry forecast in that time period. Rainfall does not appear to be substantial, but have gone ahead and added slight chance pops across the northern half of the area. Sunday and Monday continue to have a dry forecast as high pressure reestablishes itself, with just the Triad being clipped on Tuesday with a slight chance of showers in advance of the next front. Low pressure will move across the Great Lakes during the middle of the week, and it currently appears that the most likely timing for any showers or thunderstorms with the upcoming cold front will be Wednesday night. Highs will be slightly above normal for the weekend, then drop a few degrees below normal for the weekdays. Lows will be near normal through the extended period. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... As of 100 AM Friday... The chance for MVFR-IFR fog remain high early this morning (mainly 07z-14z), due to warm moist air and very light winds near the ground. Areas of mid clouds currently cover the far W Piedmont (including GSO and esp INT) as well as our NE sections, which is helping to keep fog from becoming too widespread so far, however as these mid clouds continue to push southward and break up, widespread dense fog and areas of low cigs in stratus are likely. There are no strong indicators favoring one particular terminal over another for dense fog formation, but most guidance indicates the best chances are E of the Triad, including RDU/RWI/FAY which have all seen some rain in the last 24 hours to further moisten the ground. A gradual dispersion and mixing out of fog/stratus will result in a trend to VFR conditions by 16z, persisting through early tonight. Isolated showers are possible later today, but overall the vast majority of the area will stay dry. Surface winds will remain light (under 10 kt) mainly from the NE or ENE through tonight. Looking beyond 06z Sat, another round of areas of early-morning fog and stratus producing sub-VFR conditions is possible 08z-14z Sat morning across central NC terminals, otherwise VFR conditions are favored to dominate through early Sun night. A backdoor front will drop through NC Sun night as high pressure noses in from the north, bring another chance of sub-VFR conditions early Mon morning and again early Tue morning. Mostly dry weather will persist, however, through Tue. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Hartfield NEAR TERM...Luchetti SHORT TERM...KC LONG TERM...Green AVIATION...Hartfield