FXUS62 KILM 040615 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 115 AM EST Wed Dec 4 2024 .SYNOPSIS... Arctic high pressure will bring the coldest temperatures tonight since last winter. Temperatures will warm tomorrow into Thursday before another cold front drops temperatures well below normal again Thursday night. High pressure will move across the area this weekend. && .UPDATE... No significant changes were needed to the very cold forecast with this early evening update. If there's one comfort to be had it's that wind speeds won't significantly affect the apparent temperature as high pressure and calm winds approach from the west tonight. We're still forecasting a record low temperature tonight in Florence and only 1-2 degrees from records elsewhere. Location Forecast Last Time This Cold Coldest Last Winter Wilmington 22 20 on Jan 22 19 on Jan 21 Lumberton 19 18 on Jan 21 18 on Jan 21 Florence 20 18 on Jan 22 16 on Jan 21 N. Myrtle Beach 24 21 on Jan 22 20 on Jan 21 Calm winds and clear skies accentuate microclimates from soil type differences across the area. For locations on peat/pocosin soils, lows could conceivably dip to 10 degrees tonight. Closely watch obs from the RAWS station in Holly Shelter Gameland and the Green Swamp, plus mesonet stations in Atkinson, Currie, and Maple Hill. && .NEAR TERM /THROUGH TODAY/... Although the core of coldest air aloft will be moving offshore through this afternoon, the presence of very dry air from today's mixing in tandem with the arrival of surface high pressure overhead tonight will set the stage for remarkably good radiational cooling, with record lows in danger of being broken at most of our climate sites (see CLIMATE section below for details). Lows should fall into the teens to low 20s away from the immediate coast, with some of our normally colder spots falling into the low teens. After a frigid sunrise, temps will quickly recover into the mid-upper 40s by midday. High temps should eclipse 50F during the early afternoon amidst rapidly rising 850mb temps and growing 1000-500mb thicknesses, although a robust subsidence inversion will act to limit how high temperatures can reach. With high pressure moving offshore during the morning, southwesterly low-level flow will take over and commence a brief but noticeable warming trend ahead of the next cold front. && .SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/... Very changeable conditions will punctuate the short term period as strong warm air advection will be underway initially. This will lead to high temperatures in the lower 60s Thursday which will seem very warm based on the past few days but are actually near normal. By late Thursday into Friday yet another arctic front will move across leading to more well below normal temperatures. Highs Friday will drop back to the lower to perhaps middle 40s with lower to near 20 degrees Saturday morning. && .LONG TERM /SATURDAY THROUGH TUESDAY/... Expect somewhat of a broad but methodical pattern change for the late weekend through early next week period. The deep and persistent cyclonic flow will fill and or move off to the northeast as a broad southwest flow develops. A good part of the ensemble guidance as well as deterministic suites have slowed down the embedded shortwaves thus pops have been walked back slightly. Regarding temperatures...expect another morning of sub freezing temperatures Sunday with both lows and highs warming to the lower 50s and middle 60s to near 70 respectively after this. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... VFR thru the 24 hr forecast period. Center of sfc high pressure to migrate overhead early this morning, and south of the area today. SKC all sites with canopy of cirrus likely to begin overspreading the area tonight. Looking at basically calm winds to start, becoming SW 5 to 10 kt by this aftn as the center of the high drops further south of the region. Sfc pg tightens tonight with SW winds further increasing to 10-15 kt with occasional gusts up to 20 kt possible. Extended Outlook...VFR to dominate. LLWS may develop later tonight across all terminals as a strong southwesterly low level jet develops across the eastern Carolinas. && .MARINE... Through Wednesday... Surface high pressure will shift to the coast by late tonight and move offshore tomorrow morning. North- northwesterly flow will gradually weaken through tonight as the high approaches the coast and become light and variable tomorrow morning as it passes over the waters. Southwesterly flow picks up during the afternoon and continues to increase through the remainder of the day as the gradient begins to tighten ahead of the next cold front. Seas will be primarily driven by NNWrly wind waves and decrease from 2-4 ft this evening to 1-2 ft by midday tomorrow. As southwesterly winds increase late in the period, seas will respond by increasing into Wednesday night. Wednesday Night through Sunday... Strong southwest winds will develop and or be in place overnight Wednesday into the day Thursday with a brief period of warm advection ahead of yet another arctic front later Thursday into early Friday. Small craft advisories are likely during this time and somewhat worked over water temperatures with warm advection seemingly precludes gales. Beyond this after a couple of days of northwest winds with cold air advection a broad based return/southwest flow develops. Significant seas will be highest early on with the stronger winds 5-7 feet...dropping to 1-3 feet by the weekend. && .CLIMATE... Record lows for the morning of December 4... Wilmington, NC (KILM): 21F (1876) N. Myrtle Beach, SC (KCRE): 22F (1989) Florence, SC (KFLO): 20F (1989) Lumberton, NC (KLBT): 18F (1979) && .ILM WATCHES/WARNINGS/ADVISORIES... NC...None. SC...None. MARINE...None. && $$ SYNOPSIS...ILM UPDATE...TRA NEAR TERM...ABW SHORT TERM...SHK LONG TERM...SHK AVIATION...DCH MARINE...SHK/ABW CLIMATE...ABW