textproduct: Newport/Morehead City

WHAT HAS CHANGED

Another Heat Advisory has been issued for much of ENC for Thursday

KEY MESSAGES

1) Dangerous, potentially record-breaking heat to impact the area through Friday

2) Strong cold front to bring relief from the heat this weekend into early next week, along with a risk of thunderstorms

DISCUSSION

KEY MESSAGE 1...Anomalously warm low-level thicknesses beneath anomalous ridging aloft has allowed temperatures to reach the low to mid 90s as of this afternoon. The one exception is along the OBX where an onshore flow is keeping temperatures in the upper 80s. Meanwhile, dewpoints in the mid 70s is supporting heat indices of 105-110 degrees away from the coast. The setup remains mostly unchanged on Thursday, and another Heat Advisory has been issued for most of ENC for then. The one difference on Thursday is that a stronger southerly onshore flow and stronger seabreeze is expected along and just inland of the Crystal Coast. It's expected that this will hold temperatures down just enough to keep coastal Onslow County and most of Carteret County below Heat Advisory Criteria. In light of this, those area will be excluded from tomorrow's advisory.

Friday continues to have the strongest signal for the peak of this week's heat wave, with highs approaching 100 degrees across the coastal plain, and low to mid 90s along the coast. Even with another strong seabreeze and southerly onshore flow, it should get hot enough to reach Heat Advisory criteria even along the coast. Of note, some inland locations may flirt with Extreme Heat Warning criteria. Regardless, this will continue to be a notable, and unusual, late-season heat wave for all of ENC.

KEY MESSAGE 2...A strong upper level trough will develop off the U.S. East Coast over the weekend, and this will help drive a strong cold front south through the Carolinas on Saturday. Strong heating of a moist boundary layer ahead of the front should allow moderate to potentially strong instability to develop from the Mid-Atlantic south into North Carolina on Friday. While some residual subsidence/capping may be present beneath the ridge, especially across NC, guidance show a decent signal for convection developing upstream of ENC, and making a run towards the coast during the evening or overnight hours. While the pattern is supportive of severe weather, the timing is less favorable for ENC, and there is added uncertainty regarding any residual influence of the ridge. Consequently, machine learning guidance have actually backed off some on the severe weather potential on Friday, which lowers overall confidence.

On Saturday, the ridge will continue to get suppressed further south and west with less influence across the Carolinas. This plus increased forcing along the cold front should support an improved risk of deep convection, and less limiting factors, compared to Friday. Interestingly, machine learning guidance has pulled back some on Saturday as well, and this may be related to some uncertainty regarding the timing of the front and how much instability can develop along/ahead of it. Of the two days, though, Saturday appears to have a better chance than Friday. We'll continue to monitor the potential over both days. In general, the setup favors clusters of thunderstorms, perhaps an MCS or two, impacting the area with strong to damaging wind gusts.

Behind the front, temperatures and humidity will get knocked back down closer to normal for early September, with more comfortable conditions lasting into early next week.

AVIATION /00Z THURSDAY THROUGH MONDAY/

Forecast confidence is high over the next 24 hours.

Isolated to scattered thunderstorms with gusty winds up to 40 mph are occuring over ENC this evening. With a loss of daytime heating in the next couple hours expecting coverage and intensity of storms to gradually diminish. Have VCTS for all TAF sites until 2-3Z, after which light to calm winds and generally clear skies (outside of lingering cirrus) should set in. The light to calm winds, paired with recent ground moisture, may help bring about some shallow BR/MIFG. this may allow a period of reduced VIS in BR/MIFG. Probabilistic guidance doesn't show much of a signal, but I opted to keep a mention in the TAFs to keep consistent with the previous forecast. Did trend more aggressively for OAJ, bringing it down to 3SM. Thursday should be a repeat of today's conditions, with afternoon cumulus and VFR conditions.

NOTE: AMD NOT SKED has been appended to the EWN TAFs as the site is not transmitting through normal channels. The site is still reporting via telephone so it will be monitored, but not as frequently as when it is completely operational. The next closest ASOS is at Cherry Point (KNKT).

Outlook: The risk of TSRA is likely to increase late Friday into Saturday as a cold front moves through the area. Confidence is moderate regarding the timing of the greatest TSRA risk. For now, the latest guidance shows the strongest signal on Saturday. Sub-VFR conditions will be possible with any TSRA during this time. Behind the front, a northeasterly wind shift will occur, with northeasterly flow continuing into early next week.

MARINE

Southeasterly long-period swell (2-3ft at 10-11s) from the remnants of "Dolly" will continue to impact the coastal waters through this evening. Seas may briefly lay down overnight, then build again on Thursday as a strengthening thermal gradient supports building south to southwest winds. Those winds are expected to peak Thursday afternoon into Thursday night at 10-20kt. The risk of thunderstorms is expected to remain LOW (<10% chance) through Thursday night.

Outlook: A strong thermal gradient will continue to support moderate southwesterly winds of 10-20kt Friday and Friday night. A cold front will then move through on Saturday with a northeasterly wind shift. Winds are expected to remain moderate through Monday, then lay down as high pressure builds in on Tuesday.

CLIMATE

Record High Temperatures for 09/02 (Wednesday)

LOCATION TEMP/YEAR New Bern 96/2014 (KEWN ASOS) Cape Hatteras 91/2018 (KHSE ASOS) Greenville 101/1932 (COOP - Not KPGV AWOS) Morehead City 91/1998 (COOP - Not KMRH ASOS) Kinston 103/1932 (COOP - Not KISO AWOS) Jacksonville 95/1998 (NCA ASOS)

Record High Temperatures for 09/03 (Thursday)

LOCATION TEMP/YEAR New Bern 95/2020 (KEWN ASOS) Cape Hatteras 91/2018 (KHSE ASOS) Greenville 101/1921 (COOP - Not KPGV AWOS) Morehead City 91/1998 (COOP - Not KMRH ASOS) Kinston 98/1993 (COOP - Not KISO AWOS) Jacksonville 96/2020 (NCA ASOS)

Record High Temperatures for 09/04 (Friday)

LOCATION TEMP/YEAR New Bern 98/1944 (KEWN ASOS) Cape Hatteras 92/2020 (KHSE ASOS) Greenville 98/1930 (COOP - Not KPGV AWOS) Morehead City 93/1959 (COOP - Not KMRH ASOS) Kinston 98/1980 (COOP - Not KISO AWOS) Jacksonville 96/2020 (NCA ASOS)

MHX WATCHES/WARNINGS/ADVISORIES

NC...Heat Advisory until 8 PM EDT this evening for NCZ029-044>047- 079>081-090>092-094-193>196-198-199. Heat Advisory from 11 AM to 8 PM EDT Thursday for NCZ029- 044>047-079>081-090>092-094-193-194-198. MARINE...None.