Key MESSAGE 1, Light southerly flow will steadily increase today ahead of an approaching cold front. This combined with warm low-level thicknesses will support one more day of above normal temperatures, with highs in the 70s.
KEY MESSAGE 2, A potent surface low is forecast to translate east from the Ohio Valley to the Northern Mid-Atlantic today and Friday. Meanwhile, an associated strong cold front is forecast to cross ENC tonight. A secondary cold front is then forecast to move through late Friday. Moderate to strong CAA behind each front will lead to a fairly drastic drop in temperatures compared to the above normal temperatures will are currently experiencing. Guidance suggests multiple days of highs in the 50s, with lows in the 30s and 40s. Normal highs this time of year are in the mid to upper 60s, and normal lows are in the 40s and 50s. The incoming airmass will be running a solid 10+ degrees below those normal values. Probabilistic guidance shows the highest risk of sub-freezing temperatures coming Saturday night into Sunday morning, although this risk could extend to other nights as well. Closer to the coast, some areas away from marine influences could see frost conditions if/where winds decouple enough. Assuming guidance doesn't change, frost/freeze headlines will likely be needed for a large portion of the area this weekend and maybe into early next week.
In addition to the cold, each front will be accompanied by a period of gusty winds of 20-30 mph. This will add to the chill, with wind chill values inland making it feel more like the 20s each night from Friday through Sunday. The winds may lead to elevated soundside waters, but winds do not currently look to be strong enough to cause significant impacts. Perhaps the greatest risk will be areas around Roanoke Island that can see some impacts in westerly flow. This risk would be focused in the tonight through Friday period.
12z Thursday through Monday Forecast confidence is high for the period.
SW winds are steadily increasing this morning as a deepening low migrates over the mid-Atlantic. Combined with diurnal mixing, still expecting sustained winds of 10-15 kt to pick up shortly after sunrise with gusts up to 20 kt, except along the coast where 25-30 kt is not implausible. Expect a mix of mid and high clouds along with some spotty fair weather cu in the afternoon, but VFR conditions will prevail. Main front crosses around sunset veering winds WNW to NW. Gusts will be more infrequent but overnight winds will still hover around 10 kt.
Outlook: Another surface front will move through late Friday, likely with another bump up in winds. A few SHRA may accompany this front, but a dry airmass in place should limit coverage and intensity of any SHRA development. Nw to N winds will prevail through the remainder of the period.
Latest obs show W-SW winds 5-15 kt with seas 1-3 ft. A cold front will approach the waters from the west today, moving through this evening. Winds will steadily build early this morning, peaking this afternoon and evening. Winds will peak at 15-25 kt for the nearshore waters. For the outer coastal waters from Oregon Inlet south through Surf City, warm waters of the gulf stream should support enhanced mixing. This combined with a strengthening pressure gradient should allow a period of frequent gale-force wind gusts to be realized. Gale Warning continues for those offshore zones, with SCAs for the nearshore coastal waters. Seas will build to 3-6 ft by late morning, peaking at 4-9 ft this evening south of Oregon Inlet (highest offshore) and 2-4 ft north.
Outlook: Elevated winds and seas are expected to persist through the weekend as another cold front moves through Friday night with another bump up in winds and seas. Additional marine headlines may be needed for some waters to account for this secondary wind surge. Marine conditions may begin to improve early next week, although guidance differ on how quickly the gradient will relax.
Nc, none. Marine, small craft advisory from 10 am this morning to 10 am EST Friday for amz152-154. Small craft advisory from 10 am this morning to 7 am EST Friday for amz156-158. Gale warning from 1 pm this afternoon to 1 am EST Friday for amz182-184-186-188.
