Key MESSAGE 1, Light southerly flow will steadily increase tonight into Thursday in advance of an approaching cold front. This combined with warm low-level thicknesses will support one more day of above normal temperatures. Record highs are not expected, however.
KEY MESSAGE 2, A potent surface low is forecast to translate east from the Ohio Valley to the Northern Mid-Atlantic Thursday and Friday. Meanwhile, an associated strong cold front is forecast to cross ENC Thursday night. 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 Thursday night through Friday period.
18z Wednesday through Monday Forecast confidence is high over the next 24 hours.
ENC is currently trapped in between a weak area of low pressure offshore to the south and a weak warm front lifting north towards Virginia. The flow in between both systems is weak, but a general southerly wind direction is expected through tonight. A more potent area of low pressure is forecast to move through the Ohio Valley today and into the Northern Mid-Atlantic States on Thursday. A tightening gradient south of that low will lead to increasing south to southwest winds Thursday, with gusts of 20-25kt expected. Occasional mid and high clouds will overspread the area at times over the next 24 hours, but VFR CIGs and VIS are anticipated through the entirety of the 18z TAF cycle.
Outlook: A strong cold front will move through Thursday night with a wind shift to the west or northwest. It will continue to be gusty at times. Another surface front will move through late Friday, likely with another bump up in winds. A few SHRA may accompany both fronts, but a dry airmass in place should limit coverage and intensity of any SHRA development.
Light and variable winds will steadily build tonight, becoming southwesterly 10-20kt. Winds will continue to build on Thursday, peaking Thursday afternoon and evening at 15-25kt. 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. In light of this, a Gale Warning has been issued for those waters for Thursday afternoon and evening.
Seas of 1-2ft this afternoon will quickly build to 2-5ft by tonight as southwesterly winds build. Seas are then expected to peak at 4- 8ft south of Oregon Inlet by Thursday evening, with 2-4ft seas elsewhere.
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 surge of wind. 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 Thursday to 10 am EST Friday for amz152-154. Small craft advisory from 10 am Thursday to 7 am EST Friday for amz156-158. Gale warning from 1 pm Thursday to 1 am EST Friday for amz182- 184-186-188.
