FXUS62 KILM 120242 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 1042 PM EDT Fri Apr 11 2025 .SYNOPSIS... High pressure will build in behind an offshore cold front. It will usher in dry and slightly cool air for the weekend. A warmup Monday will be reversed by a weak cold front Tuesday. Temperatures will climb towards the end of the week ahead of another cold front. && .UPDATE... Storms have diminished and moved out of the area, with cooling temps and mostly clear skies behind them. Low clouds to the north are breaking up as they move into our area, but may become thick enough to increase tonight's low temps for northern areas. && .NEAR TERM /THROUGH SATURDAY/... Latest surface analysis shows one cold front just offshore of the coastal Carolinas, while another front is exiting Appalachia and pushing into the Carolina Piedmont. Latest GOES-16 visible satellite feeds show some good spin around the upper low at 850mb. Some considerable forcing and shear vorticity is being ushered in by this low, while the broader trough at 500mb deepens and paints the jet stream across the Carolinas. After a lull this morning, showers and storms have picked up over the last couple of hours across the Piedmont and upstate SC. Some of these showers are starting to make their way into the SC Pee Dee region. Isolated to scattered showers and storms expected through this evening as the 850mb low continues to spin along with the approaching front. The question all day has been about moisture. Several members of the HREF show an inverted V sounding, and based on current convective trends, the lower levels shouldn't have much of a problem to overcoming the lower layer of virga. The area remains in a "Marginal risk" (threat level 1/5) for damaging winds and large hail. Hold skepticism that the severe chances will materialize. Precipitable water values are currently hanging around 0.80-0.90", but increased westerly flow aloft means that more moisture gets taken out of the column. Less moisture means less buoyancy for lifting parcels, which affects the hail threat. SBCAPE of 1000 J/kg matches up very well with the daytime heating, and there is a good sliver of it that falls within the -30C to -10C layer, which is what you want for hail production. However, the majority of the instability appears to be below this layer, so I have lower confidence on severe hail. Parts of the SC Midlands recorded half- inch hail recently, which seems about right. The damaging wind threat is perhaps a bit more legitimate, given elevated DCAPE values of 500-600 J/kg. This isn't a screaming signature by any means, but I think the wind threat is a bit more valid than the hail threat at this time. Shower and storm chances should taper off after 10 PM tonight as the cold front moves through. Lows tonight in the mid-to-upper 40s. Partly cloudy skies in store for Saturday, with cooler highs in the mid 60s. May have a few sprinkles or an isolated shower at best in the afternoon, particularly over southeast NC. Shortwaves traversing along the main trough bring some elevated forcing from the northwest, but it'll have a hard time with limited moisture. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... High-amplitude mid/upper trough axis will move off the coast Saturday night, with deep NW flow maintaining a dry column into Sunday. A flat ridge will begin to build overhead Sunday night. Saturday night will be the coolest night, with temps falling into the lower 40s away from the coast. Temps rise Sunday into Sunday night along with 850 mb heights. Highs Sunday will top out around 70, with lows Sunday night falling to the upper 40s inland, and 50- 55 across the coastal zones. && .LONG TERM /MONDAY THROUGH FRIDAY/... Flat ridging will build overhead Monday, followed by modest moisture return Monday night as flow aloft turns WSW. On Tuesday, PW continues to surge towards the 90th percentile for mid-April (based on MHX sounding climatology), and GEFS probability for measurable precip has reached 40-60%. The surface front will push offshore late Tuesday, resulting in a midweek cooldown with highs Wednesday ranging from the upper 60s north to around 70 south. Light winds and clear skies Wednesday night should allow temps to fall into the lower 40s away from the beaches, and even cooler in typical low spots. Temperatures will moderate Thursday and Friday with another cold front on the doorstep by the end of the week. Will maintain a low PoP Friday to account for timing uncertainties as the front approaches. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... High confidence VFR to start the forecast into tonight. Main forecast concern is low level moisture wrapping around low pressure off the Mid Atlantic coast - how deep the moisture will be and how far south will it get. Best chance for MVFR cigs overnight (starting around 4-5z) will be at KLBT - however current thinking is clouds will be more scattered in nature across our area and thus have kept TAFs VFR with SCT025-030. Low to moderate confidence in VFR overnight through early morning, with lower confidence inland and moderate along the coast. Plenty of diurnal cumulus clouds Saturday, which may initially develop at MVFR levels before quickly raising to 4-5 kft. Winds out of the NNW throughout TAF period, with gusts to 15 kts Saturday afternoon. Isolated showers may develop Saturday afternoon. Extended Outlook...High confidence in VFR through Wednesday. && .MARINE... Through Saturday...Westerly winds at 10-15 kts become northwesterly after a cold front moves through late tonight. A few gusts up to 20 kts are likely. Seas remain locked in at 2-4 ft. Saturday night through Wednesday...NNW winds are expected Saturday night through Sunday morning, with speeds on the order of 10-15 kt in a weakening pressure gradient. High pressure will slide off the SE CONUS late Sunday and persist through Monday, bringing SW return flow across the waters. The gradient will strengthen Monday and Tuesday ahead of a cold front that should make it to the coast Tuesday afternoon or evening. Wind speeds will surge to 15-20 kts, with the possibility or reaching marginal Small Craft Advisory thresholds ahead of fropa. Scattered to perhaps numerous showers are expected along and ahead of the front as it moves off the coast late Tuesday. NW winds will develop Tuesday night and continue through Wednesday as high pressure builds across the southeastern states. && .ILM WATCHES/WARNINGS/ADVISORIES... NC...None. SC...None. MARINE...None. && $$ SYNOPSIS...ILM UPDATE...VAO NEAR TERM...IGB SHORT TERM...CRM LONG TERM...CRM AVIATION...VAO MARINE...IGB/CRM