Area Forecast Discussion
Issued by NWS Wilmington, NC

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274 FXUS62 KILM 171028 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 630 AM EDT Tue Sep 17 2019 .SYNOPSIS... Hurricane Humberto will move farther out to sea in the days ahead, but will send increasing swell waves toward our beaches, producing strong rip currents. A cold front will cross the coast later today, bringing cooler and drier air mid through late week. && .NEAR TERM /THROUGH WEDNESDAY/... An upper level ridge extending from the Mississippi Valley across the Great Lakes will break eastward toward New England tonight and Wednesday as a strong shortwave dives south well off the East Coast. Convergence aloft and subsequent downward motion downstream of the ridge will cause surface high pressure to expand across the northeastern United States, pushing a cold front southward into the Carolinas this evening. Since northeasterly low-level winds are already in place, look for an increase in mid-level cloudiness and a drop in dewpoints to signal the front has pushed through. 850 mb temps in the +16C to +18C range should support inland highs in the lower 90s today, with mid-upper 80s near the coast. We`re probably getting close to the last few 90 degree readings of the year as October (with its rapidly shortening days and lowering sun angles) is only two weeks away. There appears to be too much dry air aloft within the subsidence inversion to allow for a significant chance of showers this afternoon or this evening. Dewpoints plunging into the 50s on Wednesday will similarly keep rain chances low. Highs on Wednesday should only reach 80-82 across the area as cooler Canadian air spreads in from the northeast. && .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/... Essentially an amplified blocking pattern in place at the mid levels as Humberto starts an extratropical transition in the Atlantic and troughing across the Western U.S. In between a massive ridge will keep high pressure in place nosing down into the Carolinas. Long story short, very nice conditions for this period with cool temperatures, lots of sunshine and a bit of a breeze from the northeast. Still expecting good coverage of 50s for lows both Thursday and Friday mornings with highs probably not eclipsing 80 in most areas Thursday. && .LONG TERM /FRIDAY THROUGH MONDAY/... The mid level blocking period breaks down into the weekend as a zonal flow develops. The forecast remains dry throughout the period and in fact the summer time pattern of a Piedmont Trough shows up late but with limited moisture. Temperatures will show a gradual increase from below normal early to somewhat above early next week. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... Satellite shows some stratus in Pender county trying to sing south. Think the sun will mix the stratus out before it gets to ILM. Look for VFR conditions and a moderate northeast wind. Looks like a southeast sea breeze in North Carolina by 18Z. Extended Outlook...VFR. && .MARINE... Hurricane Humberto moved to within about 300 miles of Cape Fear overnight but is continuing to move east and away from the Southeast coast. Breezy northeast winds are due to the pressure gradient between Humberto and a large area of high pressure across southeastern Canada. These winds will actually increase tonight to 20 kt or stronger as a cold front passes through from the north during the evening hours. Shower chances appear too low for mention in the forecast, but breezy northeast winds will continue through Wednesday. Large 10-second southeasterly swells coming at us from Hurricane Humberto are adding several feet to shorter period waves produced by the northeast wind. Combined seas currently 4-7 ft are expected to build by another foot tonight. The Small Craft Advisory will continue. Little in the way of forecast changes for the marine community as the big features and details are certainly intact. Wedging high pressure from the northeast, courtesy of a massive blocking ridge across the Mississippi Valley. Northeast winds of 20 knots or so will continue as will the seas of 4-7 feet. Once again extended the small craft advisory forward for all waters into Friday morning. Conditions will be relaxing shortly after this with a slowly evolving return flow for the weekend and certainly lower seas. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...Beach Hazards Statement from 8 AM EDT this morning through this evening for SCZ054-056. High Rip Current Risk from 8 AM EDT this morning through this evening for SCZ054-056. NC...Beach Hazards Statement from 8 AM EDT this morning through this evening for NCZ106-108-110. High Rip Current Risk from 8 AM EDT this morning through this evening for NCZ106-108-110. MARINE...Small Craft Advisory until 8 AM EDT Friday for AMZ250-252-254- 256. && $$ SYNOPSIS...SHK NEAR TERM...TRA SHORT TERM...SHK LONG TERM...SHK AVIATION...43 MARINE...TRA/SHK

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