textproduct: Newport/Morehead City

WHAT HAS CHANGED

Tweaked PoP forecast overnight to align with current trends.

Updated Aviation discussion

Added a small craft advisory to our southern waters.

KEY MESSAGES

1) Dangerous heat continues this afternoon.

2) Strong to severe thunderstorms possible this evening and tonight

3) Pattern expected to become more conducive for showers and thunderstorms for the weekend into early next week. Another chance for severe thunderstorms on Sunday.

4) Potential for hazardous heat and windy conditions late next week.

DISCUSSION

KEY MESSAGE 1...As expected we have gotten rather hot across ENC today with temps in the upper 90s to near 100 across inland areas with mid 80s to low 90s across the OBX today. This will threaten records (see climate section below for record high info), and as a matter of fact we look to have already broken New Bern's record high as New Bern has already gotten to 96 breaking the previous record of 95 with the potential to climb even higher before we cool off. Combined with dewpoints in the upper 60s to low 70s heat indices in the 100-109 range are prevalent across inland areas where the ongoing heat advisory is. The NWS experimental Heat Risk guidance shows much of ENC in the major category, with a few areas nearing the extreme category which lends further confidence in impactful heat across ENC through this afternoon. We will cool down slightly in the following days with highs in the low to mid 90s into early next week so while heat headlines are not anticipated, it will still feel like full swing summer, and any precautions you can take if you plan to be outside for longer durations are encouraged. While it's a lower end potential (less than 20%) the caveat to the current forecasted heat and heat indices through this weekend 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.

KEY MESSAGE 2...Besides the heat we continue to watch for the threat for strong to severe thunderstorms this afternoon and into tonight. Latest mesoanalysis shows a weak shortwave pushing offshore with attendant subsidence directly behind the departing shortwave. A second shortwave is noted further west out towards Appalachia moving east. With 850C temps generally around 20-21C this afternoon subsidence aloft has held on strong which has limited thunderstorm potential along the seabreeze this afternoon. However, outside of this we do currently note MLCAPE values between 1500-2500 J/kg, DCAPE values above 1000 J/kg, and decent mid level lapse rates around 6-7 C/km. This could counterbalance at least somewhat the ongoing subsidence as these values tend to promote quick developing updrafts if they can overcome the subsidence aloft. So while there is still a low end threat for thunderstorms along the seabreeze currently putting a ~20% threat max, if a storm could take advantage of the environment and overcome the subsidence, brief but strong down burst winds (40-60 mph) would be the main hazard within the strongest storms. Then as we get into tonight, stronger showers and tstorms develop to our W and approach the area near sunset. This activity could hold on long enough, and potentially reinvigorate over the area when the prefrontal trough interacts with the seabreeze as it works over the Coastal Plain. While MLCAPE values may be on the downtrend Fri evening lowering to 1000 J/kg or less by about 9-11PM, ongoing activity could be more cold pool dominated and sustain itself as it enters into ENC. Greatest risk is generally north of Hwy 70 with wind (40-60 mph) being the primary hazard. SPC has also highlighted this area under a Slight Risk (lvl 2/5) given the attendant wind threat. The storms over this area could also bring periods of heavy downpours. By the time the storms reach areas near the coast, they are expected to be weakening and mostly cold pool dominated, but still pose a threat of bringing strong winds along the outflow boundaries, and as such, SPC has outlined the rest of the FA in a Marginal Risk (lvl 1/5).

KEY MESSAGE 3...Synoptic pattern is expected to shift towards something more favorable for convection across ENC this weekend and into early next week with a weak front crossing the FA SAT and stalling to the S of the area into early next week when troughing aloft develops, opening moisture transport from the Gulf. However, this shouldn't be read as a high coverage of thunderstorms each day. Temps aloft "cool" slightly as heights aloft fall ahead of the front and the stout mid level ridge begins to weaken, and this may support at least a risk of higher coverage seabreeze convection on Sat, particularly along the Crystal Coast seabreeze where likely PoPs are mentioned. The ample moisture noted by PWATs rising to 2-2.5in, strong destabilization due to typical summer time heating and the height falls aloft poses a threat for the development of tstorms which could be strong to marginally severe. On Sunday a prefrontal trough develops around the coastal plain providing the necessary focus for shower and thunderstorm development Sun afternoon and evening. Activity likely starts off to the north and west and progresses E'wards as the afternoon wears on. With strong instability forecast to be in place and increase shear with values closer to 25-35 kts a few of these storms could become strong to severe in nature with the strongest activity likely noted along our northern tier. Damaging wind gusts would be the primary hazard within the strongest storms.

Early next week, higher than climo shower and storm chances are in the forecast with the greater moisture content through the column leading to PWATs in excess of 2". Additionally, deep layer shear of around 30-35kt with weak cyclogenesis along another front set to approach and stall over the area Mon may support a modest increase in the potential for organized convection, some of which could be on the strong side. The last of a series of fronts finally pushes off the coast by midweek allowing for lower precip chances outside of a daily seabreeze. We will be monitoring the approach of yet another front late next week as well.

KEY MESSAGE 4...Heat and humidity look to crank up a notch once again late next week which could bring the potential for hazardous heat indices and related health impacts. Probabilistic heat risk guidance suggests a 40-60% chance at reaching major level heat risk thresholds on Thurs/Fri. In addition to this, with the approach of a front associated with a deepening low located well to the north, breezy conditions would be possible as well if current trends hold.

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

VFR conditions prevail across ENC this evening with diurnal cu dissipating with loss of heating. VFR expected to prevail overnight with dry low levels limiting fog or status potential. The chance for thunderstorms this evening is decreasing, however, there is a shortwave and attendant cold front approaching from the west that is producing showers and thunderstorms across the southern Appalachians and along the thermal trough across the VA piedmont. These storms are expected to weaken as they progress eastward with decreasing instability overnight, but some guidance shows storms potentially reinvigorating as they approach the coast where nocturnal instability is highest, mainly east of the TAF sites. The front stalls across the region on Saturday bringing a better chance for showers and thunderstorms, especially during the afternoon and evening hours.

Outlook: Better chances for afternoon/evening showers/storms continues through weekend with front sliding off the coast and stalling into early next week, bringing tempo reductions in vsby and/or cigs accompanying the heavier showers. Another front approaches and stalls over the area MON leading to a wet period early next week with greater chances for sub VFR flight cats until the front clears through mid-week.

MARINE

Steady SW winds at 10-20 kts with a few gusts up near 25 kts are noted across our coastal waters south of Oregon Inlet and the Pamlico Sound with lighter and more variable winds noted across the northern sounds and coastal waters as of this update. The thermal gradient will continue to tighten this afternoon allowing for more frequent gusts up to 25 kts, mainly along the coastal waters south of Oregon Inlet and across the Pamlico Sound resulting in small craft advisories across these waters into this evening. Winds are then forecast to ease tonight allowing for the SCA's to end closer to 11PM. Seas will generally remain around 2-4 ft through this timeframe. However, will note while background winds do ease there will be a low end threat for a line of showers and thunderstorms to impact our waters tonight as a decaying line of thunderstorms approaches from the west after 11PM. Locally enhanced winds and seas will be possible within the strongest storms that impact our waters. Afterwards a weak cold front will begin moving through our waters from north to south with 10-15 kt SW'rly winds with gusts up to 20 kts noted to the south of the front with winds shifting to a NE-E direction at 5-10 kts behind the front. This front is forecast to continue south through the day and stall just south of the area by SAt evening. Seas remain around 2-4 ft through the rest of the period.

Outlook (Sat night through Wed): The risk of thunderstorms will increase into early next week, with best chances in the late afternoon to evening hours. A front will cross Sat and stall to the S. SWerly flow returns SUN with another chance for more SCAs ahead of a front set to approach and then stall over ENC on MON. This front will clear through by midweek with high pressure briefly returning thereafter.

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...Small Craft Advisory until 11 PM EDT this evening for AMZ135- 152-154-156-158.