Area Forecast Discussion
Issued by NWS Wilmington, NC
Issued by NWS Wilmington, NC
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547 FXUS62 KILM 170910 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 410 AM EST Fri Jan 17 2025 .SYNOPSIS... High pressure with below normal temperatures to continue today. Low pressure will bring milder temperatures and some rain back to the Carolinas for the weekend. Arctic high pressure will then return starting Sunday night with very cold temperatures expected through the mid to late week period along with the potential for some wintry precipitation during the Tue into early Wed time period. && .NEAR TERM /THROUGH TONIGHT/... High pressure centered over the southern Appalachians this morning will drift offshore during the afternoon. Weak cold air advection early in the day will quickly erode as southerly winds become established across the forecast area. High temperatures will be similar to yesterday for most areas; highs in the mid and upper 50s. Near the coast, onshore flow will push cooler air from the frigid shelf waters onshore. Highs in the lower 50s for coastal communities. Clear skies throughout the day will become overcast this evening. A shortwave aloft and developing low pressure over the Lower Mississippi River Valley will advect warm, moist air northward overnight. A building gradient and strengthening low level jet will keep a shallow mixed boundary layer near the coast. Low temperatures tonight are expected to hold in the low to mid 40s along the coast although mixing and increasing cloud cover could lead to warmer temperatures. Cooler inland after a period of clear skies just after sunset; overnight lows in the mid and upper 30s. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... Southern stream s/w trof and associated sfc low to tap Gulf moisture and low level Atlantic moisture Sat, resulting in increased liquid rain chances since WAA leading into Sat will result in temps breaking into the 50s Sat. 1st low books off to the NE and well offshore Sat with a trailing broad low pressure across the Carolinas. Will keep a rain threat Sat night into Sun but POPs not as high as what will occur during the day Sat. Most of the rainfall will occur Sat with 0.25 to 0.50 inches possible, with the hier end of this range occurring closer to the coast. Lows Sat night only in the 40s, with Sun highs again in the 50s, both above the norm. Low chance Pops for showers Sun ahead of the approaching strong cold/Arctic. Sun night is when the fun begins. Look for the passage of the cold/Arctic front followed by blustery conditions as CAA and a tightened sfc pg combine. Large amplitude upper trof will expand across 1/2 to 2/3rds of the U.S. by late Sun night, reaching and pushing all the way to the Gulf of Mexico. This will help drive that 1050+ mb Canadian Arctic south- southeastward across the U.S. border, with its sfc ridge axis reaching the Carolinas by Mon morning. Widespread low to mid 20s expected for Sun night lows with wind chills upper teens to around 20. && .LONG TERM /MONDAY THROUGH THURSDAY/... For Mon thru Wed, Southeast NC and Northeast SC will be entrenched in Arctic air. Temps will run 15 to 20 degrees below normal, possibly as much as 25 degrees below normal. Daytime highs Mon thru Wed in the 30s, possibly not breaking above 32 for highs, especially Tue and Wed. Night-time lows, widespread teens Mon night, Tue night and possibly again Wed night. Any wind addition, will obviously make it seem colder. Thus,will advertise in the HWO the threat for Cold Weather Advisory conditions possible. The threat for wintry pcpn has increased-some for the ILM CWA. With various models, GFS, European and etc., having finally started to come closer to some type of common agreement between them. At this point, looking at early Tue into Wed morning as a potential time-line for this Wintry weather threat. Low pressure is expected to push out of the Gulf of Mexico, across Fl and offshore by late Tue, then moving NE-ward, remaining well offshore as it passes by the Carolinas Tue night and Wed. With an Arctic airmass in place, this is 1 of the better scenarios for Snow to occur across the ILM CWA. Models indicate moisture from this low moving along the baroclinic zone will reach into the Carolinas, possibly as far west as the I-95 corridor within the ILM CWA. As a result, POPs have been adjusted upwards especially from the Coast to I-95. At this point, will keep it mainly snow but bear in mind, if the low tracks closer to the coast, then a wintry mixture may result with some Gulf stream air influence. And if the storm track is further offshore, no pcpn may result given the sharp moisture gradient on the western side of this system. Arctic airmass to remain with the FA going into Thu as an upper ridge axis pushes to the FA but dry conditions to prevail. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... VFR tonight. West winds shift behind a cold front early this morning. Light northerly winds and clear skies expected today. Extended Outlook... Flight restrictions expected with rain and a cold front this weekend. VFR returns with an arctic air mass early next week. && .MARINE... Through Tonight...Transient high pressure will move offshore today. Northerly winds this morning will shift throughout the day, becoming southeasterly this afternoon and southerly overnight. A poor gradient and inefficient mixing will keep winds light through Saturday morning. Gusts could reach 15-20 knots near the outer boundary of the relevant forecast zone (20 nm). Seas around 3-4 feet this morning become 1-2 feet this afternoon. Saturday through Tuesday night...Light S to SW winds Sat thru Sat night with ongoing WAA however with the cold SSTS near shore, the best S-SW winds will remain elevated across the local waters. Sun, the sfc pg tightens late somewhat, with increasing SW winds to around 15 kt g20 kt possible. Seas will slowly build across the waters Sat thru Sun, more-so from the hier waves bleeding into the local waters from offshore given the better/stronger winds offshore where SSTS likely in the 60s+. CFP Sun night, with excellent CAA(Arctic air) and notably drier air under strong and gusty NW flow overspreading the waters. Could see SCA conditions as a result. For Mon thru Tue night, look for winds to become Northerly at SCA threshold speeds at times, especially during the potential winter wx event Tue into Tue night. Reduced vsby to 1 nm or less possible in wintry mix of pcpn Tue/Tue night. && .ILM WATCHES/WARNINGS/ADVISORIES... NC...None. SC...None. MARINE...None. && $$ SYNOPSIS...ILM NEAR TERM...21 SHORT TERM...DCH LONG TERM...DCH AVIATION...21 MARINE...DCH/21