textproduct: Newport/Morehead City

WHAT HAS CHANGED

Lowered temps a couple degrees for Thu and Fri.

Lowered N OBX temps 5+ degrees through next four days.

KEY MESSAGES

1) Risk of dangerous heat later this week.

2) Pattern expected to become more conducive for showers and thunderstorms for the weekend into early next week.

DISCUSSION

KEY MESSAGE 1...Very warm low-level thicknesses are forecast to overspread the Carolinas from mid-week on as we get into a WSW low- level flow pattern. NBM guidance continues too warm with temps, however, records will still be in jeapardy, esp Fri (see climate section below for record high info). The caveats each day will be the coverage of convection (see KEY MESSAGE 2 for additional details), and the potential for high clouds/convective debris. Both of those factors can have significant impacts on the temperature forecast each day. Regardless, persistent swrly flow will allow dewpoints to steadily rise through the 70s each day. This will lead to higher humidity and increasing "feels like" temperatures even on the days with convection/clouds. The chances for afternoon convection are quite low Thu and Fri, with low level thicknesses peaking on Fri and suggesting the hottest day of the week. Probabilistic guidance currently shows a 50-70% chance of exceeding 95 degrees for inland areas away from the coast. This combined with dewpoints in the low 70s suggests a widespread area of "feels like" temperatures of ~105 degrees. This setup could lead to the first heat headlines of the summer season. The NWS' experimental Heat Risk guidance shows much of ENC in the major category, with a few areas nearing the extreme category.

KEY MESSAGE 2...From a 50,000ft perspective, the synoptic pattern is expected to shift towards something more favorable for convection across ENC esp this weekend into early next week. However, this shouldn't be read as a high coverage of thunderstorms each day. In fact most of the day will be rain free, but as is typical in convective season in ENC, hit and miss storms are going to dot the area each afternoon through early evening.

Firstly, an upper level shortwave is forecast to move through the Mid- Atlantic and Carolinas late Wednesday into Thursday. This wave is forecast to interact with a moistening and gradually destabilizing airmass, supporting clusters of convection from Virginia south into the Piedmont of NC. Locally, temps aloft will be very warm, with 850 temps of 15-20C. This will have a tendency to support some residual capping, and may tend to lead to a weakening trend with any convection that approaches our area from the west/northwest. Given the increased forcing with the wave, though, it stands to reason that at least some weak, elevated convection could survive into the area, and the forecast reflects this potential for Wed evening for a potential weakening MCS with 30% chances for showers or storms. Very warm temps aloft may continue to cap a greater coverage of convection into Friday, and thus afternoon rain chances are only 20%, so slightly below climo.

Over the weekend, temps aloft "cool" slightly, and this may support at least a risk of higher coverage seabreeze convection.

Early next week, guidance is now hinting at the potential for a front to move through with higher than climo shower and storm chances. Additionally, deep layer shear of around 30-35kt along the front may support a modest increase in the potential for organized convection, some of which could be on the strong side.

AVIATION /16Z TUESDAY THROUGH SATURDAY/

Light/vrb winds become southeasterly by mid to late afternoon into the early evening hours as the seabreeze moves inland. SCT diurnal cumulus development this afternoon dissipates with loss of heating this evening, with only sct/bkn cirrus streaming through ENC. Winds are srly tonight but remain light <10 kt. Winds turn sswrly on Wed in the 10-15 kt range with cont high clouds streaming through.

Outlook (Thu through Mon): Risk of showers/storms is quite low Thu and Fri, but not 0. Better chance for afternoon/evening showers/storms this weekend into early next week, with tempo reductions in vsby and/or cigs accompanying the heavier showers.

MARINE

Winds cont to veer to serly, then srly overnight with speeds remaining in the 5-15 kt range. Seas in the 2-4 ft range. Then tomorrow (Wed) afternoon, thermal gradient leads to inc in nearshore winds (eastern Pamlico/Croatan sounds and adjacent coastal waters N of C Hatteras), where SCA may be needed after 21Z tomorrow. Probs for 25+ kt winds are above 60% for these areas, and due to it being 3rd period, will hold off on any headlines for this attm.

Outlook (Thu through Mon): A typical summertime regime, with swrly gradient flow maxing out between 21Z and 06Z each evening leading to marginal 25+ kt winds gusts in the favored areas mentioned above. Seas of 3-5ft will be common. The risk of thunderstorms will increase late- week into early next week, with best chances in the late afternoon to evening hours.

CLIMATE

Record High temps for 06/12 (Friday)

LOCATION TEMP/YEAR New Bern 95/2016 (KEWN ASOS) Cape Hatteras 89/1922 (KHSE ASOS) Greenville 98/1914 (COOP - Not KPGV AWOS) Morehead City 92/1952 (COOP - Not KMRH ASOS) Kinston 95/1986 (COOP - Not KISO AWOS) Jacksonville 95/2016 (NCA ASOS)

MHX WATCHES/WARNINGS/ADVISORIES

NC...None. MARINE...None.