textproduct: Newport/Morehead City

WHAT HAS CHANGED

Dense fog advisory has been expanded to cover the remainder of mainland ENC, in effect until 0900edt. Aviation Disco updated.

KEY MESSAGES

1) High pressure remains in place today with light winds and near- record high temps. Chance for widespread, some locally dense, fog this morning.

2) Moisture returns with a cold front and low pressure system bringing scattered, to at times widespread, showers this weekend.

3) Cool high pressure behind the early week FROPA leads to more fall-like temps, but a prolonged period of moderate N-NEerly winds poses localized coastal flooding concerns for areas along the OBX with compromised dune structures.

DISCUSSION

KEY MESSAGE 1...SKC, decoupled winds, and increased moisture in the onshore flow has led to the development of fog. Fog has become dense at times and a dense fog advisory has been issued for zones where obs already show VIS<1/2mi like far SWern zones. This fog is expected to expand to cover zones further N. Obs and current forecast reflect what the REFS and HREF data have been suggesting: a 50-70% chance for VIS < 1/4mi across most of ENC outside of the immediate coast and far Nern tier of counties. As a result, have a mix of patchy and areas of fog in the grids across much of ENC through early morning hours.

Approach of a trough aloft in the Ohio River Valley pushing E will help shunt peaking upper ridging over the Mid- Atlantic offshore. High temps 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 low 90s inland. 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 as precipitation chances return as Gulf moisture opens up and a cold front drapes across the Sern Appalachians and pushes SEward slowly on SAT. 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 very low as ML CAPES are quite low, unsurprising for early Oct.

The front loses steam as it approaches the coast and stalls, ahead of a second reinforcing front spurred from the Great Lakes by a stronger trough aloft. For now, ensemble guidance has increased to 60-75% chance of exceeding 1" of storm total rain with this system and the QPF grids reflect this with some HiRes blended in to show the higher accumulation potential. Any rain will be helpful, especially for the coastal plain of ENC that is currently in moderate to extreme drought.

Where the front ends up SAT night and through the day SUN is dependent on the strength of the high to the N of the boundary, and where waves of weak low pressure pressure spin up. This will dictate what kind of liquid precip we'll get ahead of the next front to cross MON. Should the high pressure spill over I95 corridor, there's a chance that bulk of precip activity over inland zones will be more stratiform in nature with more convective precip offshore and over the coast. Today's model suites will feature more HiRes solutions now that we're getting into the 72hr window.

KEY MESSAGE 3...Precip chances now diminish quickly late Sun night and by Mon morning should be pushing off the OBX with drying conditions expected early next week. 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, though relatively choppy periodicity of 7 sec, but enough to lead to further beach and dune erosion concerns across the areas with severely diminished dune structures. Strongest winds of 20-25 kt with higher gusts expected MON night into TUE morning. Winds remain out of the N-NE into late- week, but speeds diminish to 10-15kt late TUE and beyond.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

All TAF sites, and most terminals across the mainland showing IFR or lower flight cats due to fog, stratus, or both. Some terminals below airport minimums at times, most probable along and south of Highway 70. Conditions will improve after daybreak Friday with pred VFR expected by mid to late morning with scattered afternoon CU. S-SW winds strengthen in afternoon, but not too strong. Another round of fog potential tonight, but not as widespread as this morning, OAJ best chances, dropping sharply as you move N/Eward from the SW.

Outlook (Sat through Tue): Precipitation chances increase for the weekend as a frontal system approaches from the northwest. Showers and maybe a few storms possible Saturday and Sunday with the potential for more extended periods of sub- VFR conditions. Stronger front crosses MON leading to high pressure and NEerly wind regime into midweek.

MARINE

Benign boating conditions continue across ENC with light S-SWerly 5-10 kt winds and 1-2 ft seas across our area waters as high pressure persists offshore. S-SW winds build to 10-15kt late this afternoon Seas generally remain around 1-3 ft at 9-10 sec into early SAT morning.

Outlook (Sat through Tue): A front will be approaching the area from the NW and pass through with winds turning NNE and inc a bit to 10-20 kt for Nern marine zones by SAT afternoon. Increasing moisture plus weak instability lead to widespread showers with a few storms. At this time, conditions look to remain below SCA levels through the weekend, but a secondary front moves through Monday with SCA winds appearing likely later Mon into Tue with 15-25 kt winds and seas of 6+ ft.

CLIMATE

Record High temps for 10/02 (Friday)

LOCATION TEMP/YEAR New Bern 93/1986 (KEWN ASOS) Cape Hatteras 89/1986 (KHSE ASOS) Greenville 94/1986 (COOP - Not KPGV AWOS) Morehead City 88/1954 (COOP - Not KMRH ASOS) Kinston 95/1986 (COOP - Not KISO AWOS) Jacksonville 93/1986 (NCA ASOS)

MHX WATCHES/WARNINGS/ADVISORIES

NC...Dense Fog Advisory until 9 AM EDT this morning for NCZ029- 044>047-079>081-090>092-094-193>196-198-199. MARINE...None.