Key MESSAGE 1), Latest surface analysis depicts a surface cold front stalled near the NC/SC border this evening. This combined with a weak embedded shortwave in southwesterly mid- level flow, the front will be a focus for on- and- off isentropically forced light rainfall early tonight. While the sfc boundary is to our south, just aloft at around 850mb we do have evidence of a frontal inversion on the 00Z sounding, suggesting the boundary is displaced aloft. This will be the focus for precip in our forecast area, generally along and south of hwy 17, in the near term.
KEY MESSAGE 2), Guidance continues to converge on a positively tilted shortwave tracking across the central plains today with the trough taking on a more negative tilt and deepening slightly as it phases with a faster moving mid-level disturbance currently pushing across the southwestern CONUS. At the surface, the aforementioned frontal boundary will serve as the focal point for cyclogenesis, intensifying Sunday as trough takes on an increasing neutral and eventually negative tilt through the day. After some track spread in the guidance the past few forecast cycles, the 12z suite continues to favor a stronger low passing quite close to the coast.
After a brief lull from the isentropically driven precipitation, more robust rainfall will return Sunday morning. Eastern NC will remain on the cool side of the low, but temps in the mid to upper 50s Sun morning along the Crystal Coast and equivalent Tds may provide just enough instability to support a rumble of thunder or two. Total rainfall on Sunday into Sunday night will amount closer to a half inch, although any convection will boost storm totals. Precipitation gradually ends from west to east Sunday night into Monday with strong CAA ramping up behind the departing low as it rapidly deepens off the Mid-Atlantic coast allowing temps to fall into the 30s. Global, ensemble and hi-res guidance all agree on a risk of minor snowfall north of Highway 264 as cooler air gets wrapped in with the moisture. Ensembles continue to favor a modest few tenths of an inch, and our forecast reflects this consensus - with little change to the previous forecast, keeping a few tenths along and north of Hwy 264. Minimal impacts expected given the sfc temps. A shortwave rotating through the departing low may keep low clouds and light precip lingering through much of Monday, although we will have dried up a decent amount at that point.
A stronger low now favors a set up of stronger winds Sunday night into Monday, and the forecast now calls for gusts pushing 45-50 mph across portions of the Outer Banks. If this holds, Wind Advisories may be needed in the next cycle. This has also raised the risk of some minor coastal flood impacts, mainly along the soundside of the Outer Banks. Localized ocean overwash will be possible for vulnerable Hatteras and Ocracoke Islands.
00z Sunday through Thursday Tonight, the boundary will creep north bringing with it lower ceilings and increased rain chances. Currently expect MVFR ceilings to move into OAJ, EWN, ISO in the next 1-3 hours, slowly progressing northward. Pgv should follow suit around 6Z, with conditions quickly deteriorating to IFR/LIFR before sunrise. For now kept LIFR mentions as a SCT003 with a 30-50% chance of occuring. Further upgrades to predominant LIFR may be needed in future updates if observations upstream start tanking to LIFR levels. Winds will be light to calm tonight as rain moves into the region. Heavier rain rates would bring reductions to visibility through much of Sunday. Winds become northwesterly at 5-10G15kt by late morning as CIGS remain at IFR levels. Rain will be off and on by early afternoon and VIS will improve to VFR, but IFR CIGs are expected to hold steady through the afternoon Sunday. Conditions are expected to improve later Sunday as the low moves away and drier air moves into the region. However, despite the improving ceilings, rainfall Sunday afternoon/evening could help mix down higher momentum air aloft. This means observed gusts could be more than what is currently forecast, potentially exceeding 30 knots in heavier showers.
Outlook: As CAA builds in behind the departing low, precip will change to snow or a rain/snow mix Sunday night through early Monday. After conditions return VFR on Monday, predominantly VFR conditions are expected through early next week.
Strong winds and elevated seas expected Sunday evening into Monday. Gale Warnings have been issued for the rivers, sounds and coastal waters.
Latest obs show N-NE winds 5-15 kt and seas 2-4 ft. Boating conditions will remain relatively benign into the first part of Sunday. Rapidly deepening low pressure moves along the stalled frontal boundary and lifts across the waters Sun afternoon into evening. Strong Gales likely to develop in W-WNW flow behind the low, and Watches have been upgraded to Warnings with peak gusts around 35-45 kt. Some Storm-force gusts are not entirely out of the question, although the probability of this currently remains low (around 10%). Seas will rise in response to around 7-10+ feet, especially beyond 10 nm offshore.
Outlook: Gales likely to continue through Monday midday but SCA conditions likely to extend well into Tuesday before westerly winds fall enough to let seas subside. Offshore waters likely to remain poor through late next week as southwesterly winds increase ahead of an approaching cold front forecast to cross next weekend.
Nc, none. Marine, gale warning from 8 pm Sunday to 7 am EST Monday for amz131- 230-231. Gale warning from 7 pm Sunday to 10 am EST Monday for amz135- 150-152. Gale warning from 8 pm Sunday to 3 am EST Monday for amz136- 137. Gale warning from 5 pm Sunday to 10 am EST Monday for amz154- 156-158.
