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.
18z Friday through Wednesday Once again VFR flight cats are forecast for a majority of the forecast period. Sw winds continue this afternoon with a few gusts up to 15-20 kts especially after the seabreeze pushes through. Could see a chance for showers and thunderstorms after 00z Sat with broken linear segments of thunderstorms approaching from the NW. Storms will be strongest over NWern portions (PGV) and weakening as they approach the coast. These storms could bring reduced VIS and strong winds. Have kept the PROB30 groups for PGV, ISO, EWN, and OAJ with the greatest chance for flight op impacts at PGV. After showers/storms roll through, light SWerly breeze and VFR CIGs and VIS are forecast through the rest of the forecast period.
Outlook: Better chance for afternoon/evening showers/storms this weekend when a front crosses the region Sat, stalling to the S and into early next week, with tempo reductions in vsby and/or cigs accompanying the heavier showers (best chance SAT afternoon over SWern zones/OAJ). Another front approaches and stalls over the area MON leading to a wet period early next week with greater chances for subVFR flight cats until the front clears through mid-week.
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.
Nc, heat advisory until 8 pm EDT this evening for ncz029-044>047- 079>081-090>092-094-193-194-198. Beach hazards statement until 8 pm EDT this evening for ncz195- 196-199-204-205. Marine, small craft advisory until 11 pm EDT this evening for amz135- 152-154-156-158.
