521 FXUS62 KILM 230454 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 1254 AM EDT Fri Apr 23 2021 .SYNOPSIS... Canadian high pressure will bring unseasonably cool and dry weather through tomorrow. A storm system will move across from the Gulf Coast states Saturday bringing moderate rain to the region. High pressure builds in for early next week across the region. && .UPDATE... Relative humidities at 70% and above, good radiational cooling, calming winds, and minimum temperatures likely to be at least 33-36 will result in some frost formation. A frost advisory is now in effect for some portions of the forecast area, and patchy frost is possible outside the warned area. Protect sensitive plants tonight to avoid damage. && .NEAR TERM /THROUGH FRIDAY/... Another unseasonably chilly night on tap for sure, but with the center of high pressure remaining over the mountains a few knots of wind should prevent ideal radiational cooling. In fact, there is no shortage of guidance that indicates that tonight is not as cool as last night, all of which were rejected. Have leaned towards the cooler envelope of model output and utilized local radiational cooling tool that hits parts of mainly Pender and Bladen counties with some lower readings these areas looking to have a repeat of last nights values in the mid 30s. Dewpoints will generally remain low enough for all but the most isolated areas of frost, so much so that will not include in the forecast. As the high shifts off the coast on Friday winds turn to the south but remain very light. Weak warm advection will be realized at the surface but since today's BL temps were so chilly Friday afternoon's highs in the upper 60s still some 10 below climo. As clouds increase Friday night ahead of the big Saturday system low temperatures will be much closer to normal. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... Low pressure system will approach the area on Saturday in advance of a powerful shortwave over the Lower Mississippi River Valley. Warm front will lift northward during the day as instability attempts to work its way northward out of southern GA and SC. Wind fields within the warm sector show the development of a potent low-level jet. For these reasons, SPC has outlined our area in a Slight Risk. The threat, for the moment, remains low confidence as morning cloud cover and increasing rain chances may limit our instability. Timing may also be an issue as the main forcing with the cold front may arrive later in the day which would provide additional challenges to the thermodynamic environment. Will say for the moment that although confidence is low, the wind field in place is enough to warrant attention as we get closer to the day. Saturday night, convection should be moving offshore with the cold front as winds remain elevated overnight. Breezy and drying on Sunday with highs in the upper 70s as high pressure builds into the area. && .LONG TERM /SUNDAY THROUGH THURSDAY/... A very quiet long-term period as high pressure builds into the area on Monday behind an exiting cold front. Most of the area will remain dry as high pressure dominates through early next week. By Wednesday, we will also see upper-level ridging which should bring above normal temperatures along with the quiet weather. High pressure meanders offshore as dew points rise into the upper 50s or lower 60s late next week. The next system approaches our area on Friday with the potential for showers and a few thunderstorms. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... VFR conditions will continue over the next 24 hours. Areas of cirrus clouds advecting overhead this morning will be joined by scattered mid level clouds by late afternoon/early evening, but widespread ceilings not expected. Surface winds will remain light, except increasing to south 10 knots along the coast with this afternoon's seabreeze. Extended Outlook...MVFR ceilings and visibilities are possible Saturday and Saturday night as low pressure spreads clouds and showers and scattered thunderstorms in from the southwest. VFR otherwise. && .MARINE... Through Friday Night... Very quiet marine conditions in store as high pressure builds in from the northwest, moving over the area early Friday and then just to our southeast later on. Winds will show considerable veering as this occurs but with speeds capped at 10kts for most of the time(staying 10-15 tonight). In the absence of any swell energy only the diminutive wind chop will remain. Southwesterly winds then increase Friday night as low pressure approaches from the west. Saturday through Tuesday Night...Southerly winds increase on Saturday ahead of a strong cold front. Most of the adjacent coastal waters are likely to see Small Craft Advisory conditions on Saturday afternoon and Saturday night with a few gusts potentially approaching Gale strength. Seas increase to 4- 7 feet with this tightening gradient and continues into early Sunday even after winds become offshore. By late Sunday, the low pressure system will move offshore and winds and seas slowly improve. By Sunday evening, expect offshore winds around 10-15 knots with seas falling to around 3-5 feet. High pressure builds into the area early next week bringing quiet marine conditions. && .FIRE WEATHER... Dry weather will continue on Friday with dry fuel moistures. Winds continue to trend lighter on Friday, with minimum RH around 30%. While this doesn't meet the criteria for elevated fire danger, there is still some concern regarding fuel moistures and associated above-normal ERC values. Another statement may be needed. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...Frost Advisory from 3 AM to 9 AM EDT Friday for SCZ017-023-024. NC...Frost Advisory from 3 AM to 9 AM EDT Friday for NCZ087-096-105- 106. MARINE...None. && $$ SYNOPSIS...ILM UPDATE...MCK NEAR TERM...MBB SHORT TERM...21 LONG TERM...21 AVIATION...TRA MARINE...MBB/21 FIRE WEATHER...