Key MESSAGE 1, Zonal flow aloft pushes offshore as a weak upper level trough out ahead of a second and stronger upper level trough noted well to the west in the Upper Midwest pushes across the Southeast late tonight into Wednesday. Associated weak shortwave also pushes across the Carolinas tonight into Thurs morning as well. While there will be forcing in place, with ample dry air over the Mid-Atlantic, outside of high cirrus overspreading ENC tonight not expecting any precip with this shortwave. Winds look to decouple tonight as well, so if cirrus remains thin enough another threat for some non impactful ground fog will be possible especially along the coast where the lightest winds will be in place. Dry weather continues across ENC through Fri with slightly above avg temps as highs get into the 70s Wed/Thurs.
KEY MESSAGE 2, Biggest change in the forecast for later this week and weekend is that both precip chances and winds have been trending down for this weekends system. Deep upper level trough in the Upper Mid-West will dive SE'wards into the Ohio River Valley Thurs into Fri with associated jet streak pushing off the east coast and strengthening during this timeframe. At the same time, strong shortwave also rounds the base of this trough Thurs into Fri as well promoting lift across the Eastern Seaboard. At the surface, low pressure in the Upper Mid-West on Wed pushes SE'wards on Thurs while deepening and then transferring its energy to a second offshore low south of Long Island. This has been where the biggest change in the forecast has occured as ensemble, AI, and deterministic guidance has trended towards a more northern track for this surface low which as a result has trended precip chances down once again to sub-mentionable levels and has lowered the winds. So while the 30-40+ mph gust risk has lowered it will still be breezy across ENC Thurs and again on Fri with steady 10-20 mph W-NW winds and gusts up to 25-35 mph possible. While winds have trended downward, if the strongest gusts are realized over a longer amount of time Thurs/Fri we could still see some minor coastal flooding concerns across the soundside OBX mainly north of Oregon Inlet, though confidence is low that this is more than nuisance water level rises given the decreasing trend in wind guidance.
Behind the system, unseasonably cool air will flood into the area as Canadian high pressure system builds into the Eastern Seaboard this weekend behind the departing low knocking highs down into the 50s for the weekend and into early next week and offer the first real opportunity for a freeze Sat night and Sun night as lows get into the 30s each night.
12z Wednesday through Sunday Some patchy shallow ground fog did develop in some isolated locations earlier this morning including PGV, while cloud cover to the south kept coverage limited to none. Widespread VFR conditions expected today with only cirri to contend with and SW winds as high pressure moves offshore. Fog formation may be a little tougher to come by tonight as pressure gradient will keep SW winds light but steady. If any decoupling does occur, however, it would not take much for some more shallow ground fog to form.
Outlook: Some patchy fog remains possible early Thurs AM if skies can remain clear enough. Approaching storm system at the end of the week brings an increase in gusty winds. Precip probabilities have continued to trend downward now favoring a more prolonged period of VFR into early next week.
Latest obs show W-SW winds 5-15 kt with seas 2-4 ft. High pressure will continue to shift offshore as next frontal system slowly approaches from the west. Light winds this morning becoming S-SW 5-15 kt this afternoon and tonight with seas mainly 1-3 ft. Winds and seas will grad increase late tonight into Thu morning.
Outlook: Have made some changes to the extended period for our waters with the biggest change being that the gale force wind potential has gone down on Fri night into Sat across our coastal waters. Strong front approaches from the west on Thurs allowing for SW'rly winds to increase to 10-20 kts with gusts up to 25-30 kts bringing our first threat for small craft conditions to our waters Thurs. Issued SCA for the central and southern nearshore waters for prefrontal SW winds and seas building to 4-7 ft. There is still a small potential for 35 kt gusts across the offshore waters ahead of the front, but that threat also appears to have trended downward. Front tracks across the region Thu night, with winds on Fri shifting winds to a NW'rly direction at 10-20 kts with gusts up around 25-35 kts. As noted before, wind forecast has trended down over the last day or so as strong low pressure looks to track well to the north of the area so while gale force wind potential has gone down, there still looks to be a solid chance at seeing widespread SCA conditions north of the Raleigh Bay area this weekend.
Nc, none. Marine, small craft advisory from 10 am Thursday to 10 am EST Friday for amz152-154. Small craft advisory from 10 am Thursday to 7 am EST Friday for amz156-158.
