Reinforcing shot of unseasonably cold air will intrude on eastern NC tonight into Friday. High pressure builds in late Friday into Saturday, then moves offshore on Sunday. A coastal low is then possible early next week.
Through tonight As of 225 PM Thursday,
Key Messages
- The coldest air of the season moves in over the next couple of days
Cool and dry airmass continues to build over much of the southeastern CONUS this afternoon as yesterday's cold front continues to progress further over the open Atlantic. This morning's thick cirrus band, which had kept temperatures very steady, has now given way to good insolation allowing temps to build back into the mid 50s.
Main focus for tonight will be secondary CAA push as reinforcing mid-level shortwave pivots overhead, ushering in anomalously low temperatures aloft (up to 15 degrees below normal). Despite clear skies, northwest winds will remain elevated and prevent more robust cooling overnight. Regardless, lows will fall into the upper 20s to around 30 for all inland zones with upper 30s across OBX. Wind surge will be felt more over OBX where gusts up to 25-30 mph are likely overnight.
Friday As of 235 PM Thursday,
Friday will, by far, be the coldest day of the week as cold trough settles overhead and 850mb temps fall below 0C. With modest CAA continuing into the day, highs will struggle to get out of the 40s. Clear and dry conditions expected as high pressure continues to expand over the area from the west. Pressure gradient will remain pinched between the high and front offshore, keeping gusty northwesterly winds in place for another day. Combined with very dry air as Tds fall well into the 10s, some fire weather concerns exist - see the FIRE WEATHER section for details.
Friday night through Thursday As of 235 PM Thursday,
Key Messages
- Coldest night of the season Friday night with some 10s possible
- Monitoring the potential for meaningful rainfall early next week
High pressure then settles in Friday night, leading to decent radiational cooling conditions, with lows in the low to mid 20s inland, and upper 20s to mid 30s along the coast. Across the coastal plain, lows may fall into the upper teens where winds remain the lightest. One caveat for lows Friday night is that there may still be just enough of a gradient to prevent complete decoupling, especially along/east of HWY 17. Additionally, high clouds moving in may offset radiational cooling effects some. Regardless, it will be well below normal.
Cold, below normal temperatures continue into Saturday, with highs still struggling to get out of the 40s, and lows falling into the 20s and 30s. Increasing cloudcover should prevent lows from getting as cold Saturday night as what is expected for Friday night.
As we move into next week, attention will turn to a pattern change across the U.S. Aloft, a positively-tilted trough is forecast to develop across the western/central U.S., putting the eastern U.S. In a more active, southwesterly flow regime. 18z/00z guidance has come into better agreement regarding the overall synoptic pattern next week. The main point of difference still centers around the potential development of a coastal low in the Monday/Tuesday timeframe. The latest suite of guidance is now honing in on a 1005- 1010mb SFC low tracking northeast from the Gulf Coast to the Carolinas or Mid-Atlantic region during this time. In general, a notable percentage of deterministic and machine learning guidance have trended deeper with this low. Meanwhile, ensemble guidance has stayed fairly consistent from run-to-run (ie. Not yet showing a deeper trend). There is plenty of time to iron out the details, but the deeper, and more consistent, trend is notable.
Based on all of the above, confidence continues to steadily increase regarding the potential for widespread, meaningful precipitation, with ensemble guidance now showing a 40-60% chance of exceeding 0.50" of rain across all of ENC.
Temperatures next week will be highly dependent on the track of the coastal low. A track near or just offshore (currently favored by guidance) would lead to colder temperatures and a cold rain. A track further inland (currently not as favored), would lead to warmer air and a risk of thunderstorms.
In the wake of the low, dry and cooler air looks to settle back into the region.
19z Thursday through Tuesday As of 130 PM Thursday,
Key Messages:
-VFR through the TAF period, with gusty NW winds possible this afternoon (~15 kts) and Friday afternoon (~20 kts)
Predominant VFR conditions expected across Eastern NC through Saturday. Nw winds persist over the region as high pressure builds in from the west and becomes centered over the area on Saturday. Winds may gust upwards of 20 knots Friday afternoon.
Sun through Mon, The high moves offshore Saturday night with precip chances increasing later on Sun as next cold front approaches, and along with it a chance for sub VFR cond developing.
As of 240 PM Thursday,
Key Messages
- SCA in effect for all offshore waters and inland sounds tonight into Friday
- Deteriorating marine conditions likely next Tuesday with increasing threat of Gales
Sub-SCA conditions in place over area waters this afternoon with northwest winds 10-15 kt and seas 3-5 feet as high pressure builds in from the west. Conditions will worsen tonight as winds increase with reinforcing shot of cold air, rising to 20-25 kt with gusts to 30 kt for all offshore and soundside waters. We would not be surprised if an odd Gale-force gust occurred over the warmer Gulf Stream waters. A SCA is now in effect for all zones except inland river (sans Alligator) starting tonight and extending into Fri afternoon.
Outlook: The lightest winds of the holiday weekend are expected Saturday and Sunday (5-15kt). During this time, seas of 2-3 ft are expected. Attention then turns to early next week as guidance continues to show a good signal for a coastal low to impact the area. There are still details to sort out here, but probability is increasing for a risk of Gales especially across offshore zones.
Nc, none. Marine, small craft advisory from 7 pm this evening to 1 pm EST Friday for amz131-135-158-230-231. Small craft advisory from 9 pm this evening to 1 pm EST Friday for amz150-152. Small craft advisory from 7 pm this evening to 4 pm EST Friday for amz154-156.
