Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 170053 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 753 PM EST Mon Jan 16 2017 .SYNOPSIS... A warming trend will occur Tuesday and Wednesday ahead of a cold front which will drop south through the Carolinas late Wednesday. Cooler and drier high pressure will follow on Thursday. Low pressure moving up from the Gulf coast will drag a warm front through the area on Friday. High pressure will build in on Saturday before another system brings unsettled weather for Sunday. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... As of 730 PM Monday...Included patchy light rain during a portions of this evening into the overnight period...mainly along and west of the I-95 corridor. Also, included showers over the adjacent coastal waters with a few possibly raking across Bald Head Island. Upped the cloud cover to mostly cloudy or completely overcast via latest Satellite imagery trends and 18Z model data. Included patchy to areas of fog this evening and overnight given latest sfc obs trends and locally run fog algorithm. Low stratus to affect the ILM CWA Carolina Coasts and adjacent waters and refrained from indicating sea fog at this juncture with the difference between sfc dewpoints and SSTS not large enough. Temps tonight will either hold steady or drift slightly lower from current values thru this evening and overnight. Basically, Not your normal diurnal temp curve. Previous.................................................... As of 300 PM Monday...Weak isentropic upglide will lead to a cloudy night but the ascent appears to be too weak and gently sloped to generate any precipitation. The temperature curve (which was troublesome this will be quite flat inland or even rise a bit overnight. Most guidance not really indicative as such again likely due to the weak nature of the thermal advection. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... As of 300 PM Monday...For as weak as the aforementioned near term warm advection is Tuesday will sure turn out a mild afternoon. This will be more a function of not being trapped under a deep and moist inversion. The moisture will not be completely eroded however as forecast soundings show some lingering moisture in the 3-5kft layer as well as above about 7500ft. The high level moisture in particular probably lingers Tuesday night and then low level moistening gets underway Wednesday compliments of approaching cold front. Timing differences with respect to the front are affecting temperature guidance with the slower WRF allowing for an even warmer afternoon than the quicker GFS. Stayed closer to the lower values due in part to support from the EC. Any significant rainfall will stay north of the area underneath the upper trough though a few sprinkles or stray hundredth of an inch or three cannot be ruled out locally. && .LONG TERM /THURSDAY THROUGH MONDAY/... As of 300 PM Monday...Unsettled remains the operative word for the extended period courtesy of a highly amplified and shortwave laden pattern. The first significant system for the eastern Carolinas arrives late Thursday into early Friday via a shearing mid level system moving across the Tennessee and Ohio valleys. A weak occluded front is paired with this system as is a stationary front to the south but these have little impact on the sensible weather. Overall the inherited chance of showers still looks good. The second more potent system at least to this point arrives late Sunday into early Monday via a more powerful and closed shortwave traversing a similar path to the first system. This system continues to strengthen via the medium range guidance with good moisture advection from the Gulf of Mexico and Atlantic. Combined with good difluence aloft the elements for a soaker are in place. Citing the dynamics, a high shear/low cape convective event is possible with plenty of details to be determined in the coming days. The temperature forecast has shown little change with the latest guidance and with a moisture laden period (even outside of pops plenty of cloud cover) there shouldn`t be much diurnal variation. Expect highs generally in the 60s and lows in the middle to upper 40s with some areas (generally coastal and southern) not dipping below 50. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... As of 00Z...Expect MVFR/IFR conditions this evening to become IFR/LIFR for the overnight hours as stratus allows for low cigs to become widespread, with patchy areas of fog as well. Light northeasterly winds will prevail. On Tuesday, anticipate deteriorated conditions to continue through midday, with a gradual improvement to VFR as cigs lift by the late afternoon hours as winds become west-southwest, around 5 to 10 kts. Extended Outlook...Cold front Wednesday, accompanied with showers and MVFR. Showers possible Friday. Otherwise expect VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 730 PM Monday...A stalled boundary extending inland in the vicinity of South Santee River has hooked up with an inverted sfc trof of low pressure just offshore and parallel to the Carolina Coasts. The 2 boundaries as a whole will begin lifting northward overnight into daytime Tuesday. This sfc pressure pattern and rather relaxed sfc pg will for the most part produce NE winds at 10 to 15 kt, veering to the ENE to ESE around 10 kt by daybreak. Significant seas will run 2 to 3 ft. A degrading ESE 1 to 2 foot ground swell at 9 second periods will combine with locally produce wind driven waves at 5 to 6 second periods. Power-wise, the locally produced wind driven waves wins this round. Previous..................................................... As of 300 PM Monday...Winds to grow lighter all night as high to our north lifts out and frontal boundary advances northward. There may be some variability in wind direction late in the period as a light southerly flow component tries to get established. Seas will average 2 to 3 ft. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... As of 300 PM Monday...With the warm front lifted out to our north on Tuesday the gradient will remain quite weak. SW flow will be capped at just 10kt and seas may drop to just 2 ft. The approach of a cold front will veer and increase the flow gradually Tuesday night and then moreso Wednesday. This front may pass through either midday or late afternoon Wednesday. The cooler surge behind this boundary is tempered enough that no headlines likely follow its passage. LONG TERM /THURSDAY THROUGH SATURDAY/... As of 300 PM Monday...Expect essentially light and variable winds Thursday via a weak pressure pattern. Wind fields will show a little better definition late Thursday into Friday as a southwest flow develops ahead of a weak front. Speeds increase briefly to 10-15 knots. By Saturday a weak northerly flow develops. Significant seas will be 2-4 feet as the weak wind fields and fetch change keep them somewhat in check. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS...SHK NEAR TERM...DCH/MBB SHORT TERM...MBB LONG TERM...SHK AVIATION...SGL

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