Key MESSAGE 1, Fog development likely tonight with mostly SKC, decoupled winds, and RHs already around 100%. Fog may become dense at times and a dense fog advisory may be needed in spots. Refs and HREF data suggest A 50-70% chance for VIS<1mi across most of ENC outside of the far Nern tier of counties and OBX. As a result, have a mix of patchy and areas of fog in the grids across much of ENC in the early morning hours.
Trough axis aloft will continue to push further off the coast with heights building in its wake as ridge expands from the Gulf. In the lower half, high pressure meanders off the coast allowing SEerly winds to veer further to a S-SWerly direction through the overnight. Upper ridging will be over the Mid- Atlantic into the end of the week before pushing offshore with the approach of an upper level trough in the Ohio River Valley that will push east as well. Pocket of dry air will be entrenched over SECONUS leading to quiet weather and a continued warming trend into the end of the week. By the end of the week the area could flirt with record highs given the set up (see climate section for more details).
For reference, normal highs in early October are around 80 degrees, and forecast highs are in the mid to upper 80s for much of ENC, with some 90s possible inland today, likely low 90s on FRI. Persistent southerly flow and increasing low- level moisture will lead to muggier lows as well, well above Normal, mid to upper 60s FRI and SAT mornings.
KEY MESSAGE 2, No real changes in forecast thinking this weekend and into next week as precipitation chances return as Gulf moisture opens up and a cold front drapes across the Sern Appalachians and pushes SEward slowly on SAT. This moisture transport opening up has slowed down slightly with the SECONUS ridge holding on a little bit longer into FRI night when the ridge axis aloft finally pivots off the coast, allowing Gulf moisture to reach ENC late FRI night. As the next wave aloft approaches, the moisture will squeeze into ENC, elevating rain chances for the weekend. While thunderstorms will be possible, the threat for severe weather is low at this time.
The front loses steam as it approaches the coast, potentially briefly stalling over Coastal Carolinas, ahead of a second reinforcing front spurred from the Great Lakes by a stronger trough aloft. For now, ensemble guidance is showing about a 30-50% chance of exceeding 1" of rain with this system. Any rain will be helpful, especially for the coastal plain of ENC that is currently in moderate to extreme drought.
KEY MESSAGE 3, Precip chances do look to diminish by TUE next week as the fronts push offshore and a strong high pressure builds in from the N and W. Stiff NEerly breeze (peaking MON night into TUE) will lead to building seas and elevated water levels. Astronomical tide levels will luckily be on the way down, but seas building to 7ft in mid length periods (7-9sec) could lead to further beach and dune erosion concerns across NOBX, Hatteras, and Ocracoke Islands due to severely diminished dune structures here. Winds remain out of the N-NE into late- week, but speeds diminish to 10-15kt WED onward. For now, TUE will probably pose the greatest risk for coastal flooding concerns.
06z Thursday through Monday VFR flight cats currently, with considerably less cloud cover this evening than prior. Another round of fog is possible across all TAF sites with calm winds and an uptick in low-level moisture. Probabilistic guidance remains bullish on low VIS with the REFS, HREF and LAMP probabilities all AoA 50% for VIS<= IFR. Maintained fog with VIS as low as 1 mile for now at all TAF sites, mainly between 07Z-13Z. After daybreak, expect any fog to dissipate and VFR conditions to return to all of ENC and persist through the day.
Outlook: Other than a nightly risk of reduced VIS in BR/MIFG/FG, a low-impact aviation period is expected through the end of the work week. Precipitation chances increase for the weekend as a frontal system approaches from the northwest. Showers and thunderstorms are possible Saturday and Sunday with the potential for more extended periods of sub-VFR conditions.
Benign boating conditions continue across ENC this afternoon with widespread 5-10 kt E-SEerly winds and 1-3 ft seas across our area waters as high pressure ridging continues to gradually push offshore. Winds will veer to a S-SW direction by Thurs evening while remaining at about 5-10 kts. Seas generally remain around 1-3 ft at 9-10 sec into THU.
Outlook: Good boating conditions are expected through at least Friday. By the weekend, a front will be approaching the area from the NW, and this is expected to lead to a modest increase in south to southwest winds, 10-15G20KT FRI afternoon. Increasing moisture plus weak instability may eventually lead to a risk of thunderstorms as well, especially on SUN. At this time, conditions look to remain below SCA levels through the weekend, becoming increasingly more likely early next week behind a stronger reinforcing cold front on MON.
Nc, none. Marine, none.
