Newport/Morehead City forecast discussion

What Has Changed

Coastal low development becoming more likely, although uncertainty still exists on strength, location, and track. Wind gusts and wave heights increased with this forecast update.

Key Messages

pressure system offshore.

4) Drastically cooler behind the front and low for Sunday, along with continued breezy northeasterly winds.

Marine: Gale Watch in effect along with prolonged large seas this weekend into next week as offshore front stalls with long period fetch of northeasterly swell and increasing chances of low pressure development off the southeast coast.

Discussion

KEY MESSAGE 1..A stratus deck along a stationary back door cold front is spread through much of the region. Just south of this stratus deck, clear skies, low level moisture, and light to calm winds is providing ideal conditions for fog formation. Observations have consistently been at 1/4 miles in Onslow, Duplin, and southern Craven counties. While no observation sites are in the area, it is likely patchy dense fog is also occuring in Jones and Carteret counties. A SPS is in effect for patchy dense fog this morning in the aforementioned counties.

KEY MESSAGE 2...Back door cold front shifts back north today and flow becomes southwesterly through the CWA. If the stratus breaks up early in the morning, we should have another near record warm day for ENC as temps soar into the upper 80s inland. (record high climate section below). However, if the cloud cover this morning lingers, we could have a delayed start to the heating and temps could max out in the mid 80s.

KEY MESSAGE 3...

A cold front will be passing through the region Saturday, stalling offshore along the Gulf Stream. A coastal low forming offshore along this front is becoming more likely, but there is still high uncertainty on where/when the low forms, how deep it gets, and where it tracks. While there are still three main camps as far as solutions go, confidence is trending up that a coastal low will form.

Once the low forms out over the gulf stream there are three main steering paths that models are hinting at right now. The most likely scenario at this time remains that the low forms and stays over the gulf stream picking up strengths as it does so but remains in a fairly constant longitudinal range offshore. This will result in minor to low end moderate impacts to our NC coastline, as strong NE winds paired with a low deepening offshore bring minor to low-end moderate coastal flooding, beach erosion, and overwash concerns.

The next likely outcome is the low develops right along the coast and holds it there for a much more prolonged event. Should this solution play out, we could be looking at a long duration of strong NE winds and high seas. This outcome would result in moderate impacts to the NC coastline. In addition, the track of the low would have to be monitored in case it shifts back west towards eastern NC. There is still considerable spread in the location and intensity details for models showing this outcome.

Finally, the least likely outcome is the low either not develops at all or develops it much later and much further east than any of the other scenarios. With a strong high building in, we would still see strong NE winds, albeit for a shorter duration, and elevated waves bringing minor coastal impacts.

Regardless of which scenario plays out, there is HIGH confidence of marine impacts, and potential for waves 8+ ft reaching portions of the OBX. A High Surf Advisory is in effect for Hatteras Island and northern OBX. Winds advisory potential continues for the OBX zones, as well as perhaps portions of the adjacent coastal mainland. Will have to watch for minor coastal flood concerns for srn portions of Pamlico Sound and the coastal areas of the OBX with the sustained NE flow.

KEY MESSAGE 4...Coolest and driest airmass for the fall season thus far builds in behind the front Sat night and beyond with temps taking a nosedive with highs in the 60s and lows in the 40s (inland) and 50s (beaches). However, depending how offshore the front makes it, could keep things a bit milder than fcst if some clouds advect in from offshore keeping the nighttime mins a bit warmer than advertised.

Aviation /07Z Friday Through Tuesday/

Forecast confidence is moderate to high over the next 24 hours. A slow moving or stalled cold front is bringing widespread low stratus and/or fog to the region. CIGs will quickly improve once the front moves back north in the morning, but guidance differs on how quickly this transition will occur. Once the front is to the north of any TAF site, then VFR conditions should prevail. On Friday, southerly winds will become gusty at times, with gusts to 20kt likely.

Outlook (Sat through Mon): Strong and slow moving cold front brings widespread light rain on Sat, with sub VFR likely behind the front later Sat with frontal inversion developing, along with gusty north winds through the day Sat. Clearing skies Sat night with winds tapering off as high pres attempts to build in for the latter half of the weekend into next week.

Marine

Latest obs show continuing W/SW winds 5-10 knots with seas mainly 2-3 ft. A back door cold front lifts back north today, with SW winds steadily increasing ahead of a cold front moving through the region Saturday.

Outlook (Fri through Mon): A strong cold front has trended slower, now not expected to clear the waters until Sat, at which point it is likely to form a low pressure system offshore. Gale Watches have been converted to gale Warnings beginning 15Z Saturday for all waters except the southern rivers. A Gale Watch has been issued for the Neuse River, as probs of gale force gusts have increased. SCA has been issued for the Pamlico/Pungo rivers. Probabilities indicate high confidence in Gale Force Winds but likely not achieving consistent storm storm force gusts. However, it is worth noting that the wind forecast has trended up a tad, and the forecast is now at the high end of gale force gusts for offshore waters (20-60nm). Further increases in gust forecast would put us at Storm Force thresholds. Seas build quickly as well, with seas of 6-10+ ft in 0-20nm zones, increasing to 10-20 ft in 20-60nm zones along the Gulf Stream later this weekend. Duration of strong wind gusts and high waves is uncertain at this point and will likely bounce above and below the threshold well into next week.

Climate

Record High temps for 10/16 (Friday)

LOCATION       TEMP/YEAR 
New Bern        86/1975  (KEWN ASOS)
Cape Hatteras   83/1919  (KHSE ASOS)                          
Greenville      90/1968  (COOP - Not KPGV AWOS)               
Morehead City   84/1917  (COOP - Not KMRH ASOS)               
Kinston         86/2008  (COOP - Not KISO AWOS)          
Jacksonville    88/1975  (NCA ASOS)

Mhx Watches/Warnings/Advisories

NC...High Surf Advisory from 2 PM Saturday to 8 PM EDT Monday for NCZ203-205. MARINE...Gale Warning from 11 AM Saturday to 11 AM EDT Monday for AMZ131-135-150-152-154-156-158-180-182-184-186-188-230- 231. Small Craft Advisory from 11 AM Saturday to 11 AM EDT Monday for AMZ136. Gale Watch from Saturday morning through Monday morning for AMZ137.

DISCUSSION...RJ AVIATION...RJ MARINE...RJ