Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 240603 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 103 AM EST Wed Jan 24 2018 .SYNOPSIS... Gusty west to northwest winds and drier air will filter in behind the cold front tonight. Dry and near seasonable weather are expected Wednesday through Fri as high pressure slowly migrates across the area. Weekend temperatures will warm again ahead of a cold front, along with showers late Sat and especially during Sun. After the passage of this cold front late Sunday, a return to seasonable temperatures is expected on Mon. && .NEAR TERM /THROUGH TODAY/... As of 845 PM Tuesday...A secondary cold front depicted by the sfc pressure pattern and associated with a small band of widely scattered mid or high level clouds is progged to drop southeast across to south and east of the FA later this evening into the pre-dawn Wed hrs. At the moment, this band was located from New Bern across Red Springs to Hartsville. After this secondary CFP, sfc winds will further veer to the WNW to NW and accompanied by the surge of colder and continued drier air infiltrating the FA. Ahead of this secondary cold front, sfc dewpoints have already dropped into the 30s except for the coastal counties of southeast NC where 40s were still prevalent. This last area will follow suit during the nest hour followed by the secondary cold and drier air push. Previous...................................................... As of 555 PM Tuesday...Some tweaks to winds closer to the coast due to a cold frontal passage this evening. As winds veer to the west, lower dewpoints, ie. drier air, will filter across the region and over the adjacent Atlantic waters. This will help dissipate and drive the sea fog further off the coast with the Bald Head Island the last to improve. Previous........................................................ As of 300 PM Tuesday...What a difference 8 hours makes! This morning started with a line of moderately strong convection and muggy air, and is ending with an absolutely beautiful afternoon with highs exceeding 70 and dewpoints crashing into the 30s. The cause of this changeable weather is a cold front which bisecting the CWA at this hour. A line of showers which was along this boundary has dissipated and only a few residual CU exist anymore. This is due primarily due much drier air which has filtered into the column, and PWATS continue to drop as the dewpoint gradient across the front is nearly 30 degrees F! The cool advection lags considerably so today will remain warm, but the dry air combined with very strong winds atop the PBL will allow winds to gust up to 30mph through this eve as the direction shifts gradually to the west. Winds will become NW tonight as high pressure begins to ridge into the area from the west, driving much cooler temperatures, and mins are forecast to be 30 degrees below aftn highs, falling into the mid and upr 30s. Much cooler temps will occur Wednesday but will still be around seasonable norms in the upr 50s but with a very dry column, bright sunshine, and light winds, it will feel quite nice Wednesday as typical late January weather sets up. && .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... As of 300 PM Tuesday...A dry air mass will get even drier as mid to upper trough moves off the east coast and high pressure migrates eastward. Moisture profiles show limited moisture up just above h85 Wed eve but once the trough passes off shore, deep NW-N flow will funnel in even drier and slightly cooler air. Pcp water levels will drop from already dry levels near .35 to near .20 inches. Aside from a few passing clouds as mid to upper trough swings through Wed eve, expect dry weather with plenty of sunshine during the day on Thurs and clear skies at night. Dewpoint temps will drop down into the mid 20s through Thurs. THe 850 temps will drop from around 2C Wed eve to -2C by early Thurs morning. CAA overnight Wed night will help bring temps down close to 30 degrees by daybreak. This shot of slightly cooler air will make its way in, leaving temps slightly below normal on Thurs, with highs within a few degrees of 50. Great radiational cooling will take place Thurs night as high pressure migrates overhead allowing for calm winds across much of the area and a continued cloud free sky. Temps should drop to the mid 20s inland to near freezing along the coast Thurs night. && .LONG TERM /FRIDAY THROUGH TUESDAY/... As of 300 PM Tuesday...Upper level ridging across the eastern U.S. Friday and Saturday will give way to an approaching upper trough early next week. There are amplitude differences with the trough between the GFS and the ECWMF/Canadian/NAVGEM that strongly influence our sensible weather for Sunday and Sunday night. Surface high pressure along the East Coast Friday should move off the coast Saturday. This will allow for a modified marine airmass to spread back onshore with rising temperatures and dewpoints for Saturday. The aforementioned upper trough should dig into the eastern U.S. Sunday and Monday. The GFS is anomalously flatter with this feature compared to virtually all other models, and the surface low it develops remains weak and trickles eastward across Florida. Other models show a stronger surface low moving northeastward out of the Gulf and through the Piedmont/Foothills region on Sunday, drawing in a stronger southerly flow across the coastal Carolinas. Following the more amplified models, we`re forecasting PoPs increasing to 60-70 percent on Sunday. Forecast soundings from the ECMWF show modest surface-based instability possible, and we`ll maintain the mention of isolated thunderstorms. All models show clearing developing Monday as a glancing shot of Canadian air spreads into the Carolinas from the north. Low temperatures Monday and Tuesday nights could drop to freezing. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... As of 06Z...High pressure will build in from the west through the period. The only feature of note will be a dry cold front crossing the area this evening. Likely see some high clouds with the front but little more. Front will provide a reinforcing shot of colder air and kick up northwest winds a bit overnight. VFR conditions will prevail through the period with generally west to northwest winds 10 kt or less. Extended Outlook...VFR through the end of the forecast period. && .MARINE... NEAR TERM /THROUGH WEDNESDAY/... As of 845 PM Tuesday...Dense sea fog has been cancelled. Latest Goes 16 Imagery ie. 10.3-3.9 micron, illustrates the deeper sea fog now northeast of the local waters with a few pockets closer to 20 nm out. With 40s sfc dewpoints advecting across the local waters at the moment, and progged 30s to drop into the 30s, sea fog will no longer be a concern across the FA and has been cancelled. SCA conditions to prevail into the pre-dawn Wed hrs...mainly for risen significant seas from earlier strong S-SW winds. Seas will especially begin to subside once winds further veer to the WNW to NW after the secondary CFP. Dominant periods will run 6 to 8 seconds, a pseudo or borderline swell. Previous...................................................... As of 600 PM Tuesday...Extended the Dense Fog Advisory to 10 pm tonight. Extended the SCA to 3 AM Wednesday. Latest Sat imagery specifically the 10.3-3.9 micron channel, displays the sea fog nicely across the local waters. As the drier air advects into the local waters under Westerly winds, the sea fog will both get pushed eastward while dissipating at the same time. Latest seas and local winds are running slightly hier than fcst this evening into the overnight hrs. Have adjusted both winds and seas at current readings and meshed them with the overnight fcst. Previous..................................................... As of 300 PM Tuesday...Small Craft Advisory conditions ongoing across the waters will gradually ease as a front pushes offshore later this aftn. Although winds will remain elevated much of tonight, the combination of slightly lower winds speeds, 15-20 kts, along with a shift in direction to the west will push the highest seas away from the coastal waters. The SCA is expected to expire on time at 6pm. Winds will become westerly tonight and then NW by Wednesday morning before backing again to the west late in the period. This is in response to high pressure building in from the west, and this relaxing gradient will allow speeds to fall to 5-10 kts during Wednesday, followed by seas dropping through 3-4 ft tonight and 2-3 ft on Wednesday. Marine dense fog advisory remains in effect as well, also through 6pm. Latest GOES East imagery and beach cams show very dense fog along the Brunswick County coast and much of the waters just away from shore. As winds begin to shift, the ideal trajectories will fade so fog will push offshore and diminish this evening. SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/... As of 300 PM Tuesday...A reinforcing shot of cold and dry air will move over the area waters Wed night into Thurs as upper trough moves through and high pressure builds in from the west. Light and more variable winds late Wed will pick up in northerly surge overnight Wed. This will push winds up to 10 to 15 kts with some higher gusts Wed night into Thurs. Expect seas around 2 to 3 ft to rise slightly to 2 to 4 ft through Thurs before coming back down as northerly winds lighten and veer around to the NE through Thurs night. Seas will be back down to less than 3 ft by Fri morning. LONG TERM /FRIDAY THROUGH SUNDAY/... As of 300 PM Tuesday...High pressure along the East Coast on Friday will move out to sea Friday night, allowing easterly winds to develop along the Carolina coast. Low pressure should develop in the northern Gulf of Mexico on Saturday, but where the low moves Saturday night and Sunday is still quite uncertain. The GFS model has been very consistent for the last couple of days showing the low moving eastward across Florida with relatively little impact on our wind speed or direction locally. The bulk of the other global weather models show the low moving northeastward through the Piedmont and Appalachian Foothills Sunday and Sunday night. The difference we`d see in wind/weather conditions between these two possibilities is enormous. Following the consensus solution shown by the ECWMF, Canadian, and NAVGEM models brings increasing southerly winds across the Carolina coastal waters Sunday and Sunday night. The long southerly fetch is expected to bring Small Craft Advisory conditions due to seas, and probably due to winds too. Showers will become likely with maybe a few thunderstorms embedded Sunday night. The cold front associated with the low may reach the area late Sunday night with winds shifting westerly before sunrise Monday. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...Small Craft Advisory until 3 AM EST early this morning for AMZ250-252-254-256. && $$ SYNOPSIS... NEAR TERM...DCH/JDW SHORT TERM...RGZ LONG TERM...TRA AVIATION...III MARINE... is the U.S. government's official web portal to all federal, state and local government web resources and services.