AFDILM Area Forecast Discussion National Weather Service Wilmington NC 347 AM EST Thu Nov 21 2024 .SYNOPSIS... Colder end to the week expected behind a strong cold front, possibly leading to frost or even freezing conditions inland each night. High pressure will move off the coast early next week with warmer temperatures expected. A weaker cold front could move through toward mid week. && .NEAR TERM /THROUGH TONIGHT/... A strong cold front has moved offshore early this morning with gusty NW winds and dew points mainly in the 30s across the region. Expect these winds to slow down late tonight into early this morning as the pressure gradient relaxes. After sunrise, the growing boundary layer (expected to reach up to around 850mb at peak heating) will tap into faster winds aloft and allow for gusty west winds up to around 20-25 kts to develop around midday and continue through the afternoon. High temps will struggle to reach 60F amidst persistent cold advection and a robust subsidence inversion. With the loss of heating, gusty winds driven by vertical mixing will subside late this afternoon into this evening. However, another surge of WNW flow with even drier dew points behind a secondary cold front is expected to push in between 23-04Z this evening, which should bring some temporary gusty winds back into the mix, although speeds will be less than during the day. A weakening pressure gradient will allow for winds to decrease during the latter half of the night, and with clear skies in place, temperatures have the potential to drop to around the freezing mark, particularly across the northern tier of counties in our CWA. Therefore, a Freeze Watch has been issued to account for this possibility. Dew points depressions should be large enough to preclude widespread frost, but preferred areas near a water source or irrigated land may be able to yield frost due to locally higher dew points. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... Highlights: *Dry w/ below normal temperatures *Frost/freeze conditions possible inland Fri/Sat nights Confidence: *Moderate to High Details: General troughing will prevail through Friday night with high pressure returning thereafter. Temperatures will stay below normal through the period with highs only in the lower to mid 50s Friday and lower 60s Saturday. Overnight lows will be in the 30s away from the coast each night, possibly near freezing in spots. Such temperatures could support frost as well, although there is some uncertainty regarding temps, humidities and winds. Also, should note that the issuance of Freeze Watches/Warnings and Frost Advisories will be predicated on whether freezing temperatures occur tonight which would end the growing season in these areas. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... Highlights: *Warming trend early in the week w/ above normal temps starting Mon *Cold front could bring cooler temps and a few showers toward mid week Confidence: *Moderate Details: High pressure will be shifting offshore bringing moderating temps and moisture levels. A cold front looks to approach toward mid week, possibly moving into and/or through the area as early as Tuesday. Moisture and forcing appear weak so not expecting much rainfall with this feature, although some showers will be possible. && .AVIATION /08Z THURSDAY THROUGH MONDAY/... A strong cold front has crossed through all terminals as of this writing with gusty northwest winds at all terminals. As the pressure gradient relaxes behind this initial surge, expect winds to gradually slow down as the night progresses. Mid-level cloudiness will clear out over the next 2-3 hours, leaving VFR conditions for the remainder of the period. After sunrise, a growing boundary layer will promote a return of breezy west winds with gustiness returning around midday with gusts expected to reach around 20-25 kts during the afternoon as the boundary layer reaches up to around 850mb. Winds will relax again after sunset, but remain steady westerly. Extended Outlook...Expect VFR through the period as high pressure maintains control. Gusty winds will be the only concern on Friday and Saturday afternoons. && .MARINE... Through Tonight... Breezy NW winds will gradually subside this morning and back to westerly as the pressure gradient weakens and a weak surface ridge passes through. Winds and gustiness increase again this afternoon and veer to WNW this evening as another surge of cold advection pushes in. Seas will be dominated by wind waves with 2-4 ft waves temporarily subsiding this morning and early afternoon before rebounding to 3-5 ft this evening as a result of the increase in winds later in the day. Some 6 ft waves may be found in outer portions of the coastal waters near 20nmi offshore of Cape Fear during the first half of the night before gradually subsiding thereafter. Friday through Monday...A tight pressure gradient and cold advection will keep winds/seas elevated through Friday night and a Small Craft Advisory remains in effect through this period. High pressure will then build into the area this weekend leading to a relaxation of the pressure gradient and thus improving marine conditions. && .ILM WATCHES/WARNINGS/ADVISORIES... NC...Freeze Watch from late tonight through Friday morning for NCZ087-096-105. SC...Freeze Watch from late tonight through Friday morning for SCZ017-023-024. MARINE...Small Craft Advisory until 7 AM EST Saturday for AMZ250-252- 254-256. && $$