Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 181850 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 250 PM EDT Tue Jul 18 2017 .SYNOPSIS... Shower and storm coverage will decrease in the days ahead as a front dissipates and drying aloft takes place. A strong ridge of high pressure will bring the hottest temperatures of the summer season late week and weekend, and heat advisories and even warnings may be needed. && .NEAR TERM /THROUGH WEDNESDAY/... As of 300 PM Tuesday...Isolated to widely scattered showers and thunderstorms are expected through the evening before losing their luster with the loss of heating. A mid/upper low across central NC has already displaced the deepest band of moisture farther offshore per water vapor imagery. The mid/upper low will slowly meander across eastern NC over the next 12-36 hours and bring a drier column to the forecast area. Still enough instability and lingering moisture warrants mainly diurnal isolated to widely scattered convection during Wednesday. Wednesday`s max temperatures will rebound from the cloud limited and rain-cooled high temperatures observed today across a large part of the forecast area. However, even warmer temperatures are expected beyond the near term period as the focus shifts from heavy rain producing convection to heat index concerns. Otherwise, could see some fog develop overnight, especially across those areas that received recent rainfall. && .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/... As of 300 PM Tuesday...Unusual summertime cutoff upper low will drift right overhead at around 06Z Thursday as it sinks southward. Thursday afternoon and night it then turns west and retrogrades into Savannah, feeling the influence of a large anticyclone covering most of the south-central U.S. Unsettled weather had preceded this feature while we were on its eastern side but we now spend the short term forecast period under the subsidence associated with its exit, which will lead to negative differential vorticity advection and height rises. Most of the period thus appears rain-free save for the possibility of very isolated thunderstorm activity along the seabreeze during peak heating Thursday afternoon. This is suggested by the GFS and SREF but not the WRF. The current forecast of 20 POPS along the coast looks reasonable. Thursday highs will be a few degrees above climatology while lows will remain slightly elevated both nights. && .LONG TERM /FRIDAY THROUGH TUESDAY/... As of 300 PM Tuesday...Initially mid level low pressure will be wobbling westward along the Gulf Coast undercutting a potent ridge centered along the Mississippi Valley. This area or Col in meteorological parlance will keep convection to a minimum via mid level capping although this time of year it can never be ruled out. I suspect as we move forward in time small pertubations may show up in the weak circulation thus increasing pops albeit slightly. The pattern becomes more conducive for convection in time and this is reflected in the later parts of the forecast. Guidance has trended a little lower on overall temperatures especially the ECMWF but still expect most of the period to see temperatures somewhat above normal. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/... As of 18Z...MVFR conditions are possible in/near any widely scattered showers and tstms through the afternoon period along with a few left over strato-cumulus decks from earlier storms. Potential for MVFR VSBYs will increase overnight, especially at KILM, KFLO, and KLBT. VFR conditions expected to prevail after 13Z Wednesday with less coverage of convection during the day Extended Outlook...Flight restrictions are not foreseen at this time. && .MARINE... NEAR TERM /THROUGH WEDNESDAY/... As of 300 PM Tuesday...A weak trough along the coastal waters and earlier convection has helped to skew the local wind field. Overall the flow is expected to become briefly southwest by the evening then veer to an light offshore direction during the early morning hours. A sea breeze circulation will turn the flow back around to a southerly direction during Wednesday. Speeds around 10 knots through the period outside any convection. Seas will average 2 to 3 ft through the period. SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/... As of 300 PM Tuesday...Very light SW winds and just 2 ft seas through most of the period. An upper low will somewhat disrupt the normal 10-15kt/2-3 ft forecast usually borne of the Bermuda high this time of year. 15kt winds may represent a few gusts but will generally not make it into the forecast and seas will remain capped at 2 ft. A minor uptick in winds/seas may be noted Thursday night as the upper feature retrogrades south and west. LONG TERM /FRIDAY THROUGH SUNDAY/... As of 300 PM Tuesday...Expect southwest winds of 10-15 knots for the duration. There will inevitably be some nocturnal acceleration from time to time but this amount of detail is all but impossible to put into the extended. Significant seas will be 2-4 feet. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS...SHK NEAR TERM...SRP SHORT TERM...MBB LONG TERM...SHK AVIATION...SRP is the U.S. government's official web portal to all federal, state and local government web resources and services.