911 FXUS62 KILM 091725 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 125 PM EDT Tue Oct 9 2018 .SYNOPSIS... Warm and increasingly wet conditions will continue for the next couple of days. What remains of Michael will affect the area Thursday and possibly into Friday. A cold front will move across the area this weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 1030 AM Tuesday...Only minor changes made with the morning update. High pressure southeast of New England and Hurricane Michael over the eastern Gulf of Mexico are maintaining a large easterly fetch across the Carolinas along w/ a weak coastal trough. While showers/thunderstorms are possible the areal coverage is expected to remain low today. Strengthening onshore low-level flow and Theta-E advection overnight will support a better potential for rainfall, especially across portions of northeast SC initially. Otherwise, followed a blend of guidance today and tonight. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... As of 300 AM Tuesday...Hurricane Michael, developing central CONUS 5h trough and the mid-level ridge over the western Atlantic will be the key features during the period. Direct impacts from Michael (which remain surrounded by uncertainty) are expected late in the period. On Wed, well ahead of the storm, a deep tropical moisture tap develops as the flow around the west side of the 5h ridge and on the east side of Michael pushes precipitable water well over 2 inches across the southeast. Although mid-level support is limited the abundance of moisture and diurnal heating should be enough to generate an abundance of showers and thunderstorms. Additionally it appears low level convergence may line up with the areas of deepest moisture. This could lead to a band of very heavy rainfall lifting north across the forecast area, basically a predecessor rainfall event, during the day Wed and is something to keep an eye on. Environment will support storms with very high rainfall efficiency, but storm motions will be in excess of 20kt, making training storms the biggest concern Wed into Wed night. Micheal will be weakening as it approaches the region Thu before cross the region Thu evening and then exiting Thu night. As the weakening cyclone moves toward the region tornados will become a concern, especially as the increase in shear will be coincident with diurnal heating. All of the guidance is showing an abundance of dry air wrapping into the storm as it moves across the forecast area Thu night. Total rainfall during the period will be in the 2 to 4 inch range, but with potential for higher amounts. Given the state of some rivers and the ground post Florence this may be enough to cause flooding concerns for many areas. Temperatures will run well above climo through the period with lows running close to climo highs! && .LONG TERM /FRIDAY THROUGH MONDAY/... As of 300 PM Monday...Micheal will be bringing deteriorating conditions on Thursday. The speed at which will hinge upon the highly uncertain timing; as models are trending considerably slower. Similarly the extent/severity of the effects on the local area are yet unknown but it seems likely their significance will be worsened by the area's sensitivity (wet ground leading to fallen trees, water damage from roofs that have yet to be repaired, etc.) stemming from Florence. Cooler and drier air filters in rapidly behind the storm on Friday though again the overall sense of timing may trend slower. Surface wedging lasts into Saturday though warm advection may begin to top the surface airmass. This warm advection may lead to some rain chances on Monday especially as a strong cold front approaches. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... As of 17Z... Some MVFR ceilings are possible during the day as shallow showers move onshore especially near the coastal terminals. Persistent onshore flow will allow for the possibility of showers and thunderstorms throughout the day, however, little impact to aviation is expected. Overnight, easterly flow will maintain the possibility of showers at coastal terminals with MVFR ceilings possible at the inland terminals. Moderate confidence in little to no fog overnight. With a tight PG oriented SE to NW will produce a moderate SE wind through a deep layer associated with the approach of Hurricane Michael. With this, precipitation chances will increase, especially later tonight into Wednesday with tropical showers. Extended Outlook...Tropical cyclone Michael is expected to impact the area Wednesday night through Friday, bringing periods of heavy rain with IFR ceilings, as well as sustained winds of 30-40 kt with gusts potentially in the 40-50 knot range, especially at the coastal terminals. && .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 1030 AM Tuesday...A combination of swell and ESE fetch has resulted in steep waves along the adjacent coastal waters. A Small Craft Advisory is already in place to account for the rough seas. While the fetch will veer slightly as high pressure to the northeast shifts farther offshore the flow will remain onshore. Seas will continue to build through tonight as a result. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... As of 300 AM Tuesday...Conditions will steadily deteriorate late Wed through Thu night as Hurricane Michael approaches from the southwest and then crosses the area late in the period. Although there remains uncertainty with respect to track and strength, tropical storm force winds affecting the waters during the mid to late part of the forecast period seems like a good bet. Onshore flow Wed will not be particularly strong however extended period of onshore flow will keep seas over 6 ft before increasing winds late Wed night and Thu push seas over 10 ft. LONG TERM /FRIDAY THROUGH SATURDAY/... As of 300 PM Monday...Tropical storm-force winds to spread northward across the zones on Thursday though there are still considerable differences in model guidance (mostly trending slower). Conditions likely at their worst Thursday night or Friday morning as winds abruptly turn northward and start decreasing behind the exiting storm. High pressure wedge setting up over land on Saturday bringing NE winds. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...High Rip Current Risk until 8 PM EDT this evening for SCZ054- 056. NC...High Rip Current Risk until 8 PM EDT this evening for NCZ106- 108-110. Coastal Flood Advisory until noon EDT today for NCZ107. Beach Hazards Statement until 8 PM EDT this evening for NCZ110. MARINE...Small Craft Advisory until 8 AM EDT Thursday for AMZ250-252- 254-256. && $$ NEAR TERM...SRP SHORT TERM...III/CRM LONG TERM...MBB AVIATION...21/SRP