Key MESSAGE 1, Ongoing shower and thunderstorm activity east of Hwy 17 and along the Outer Banks is quickly moving east and should be out of the CWA within the next hour or two. Low level clouds across the coastal plain should begin lifting shortly as well. This likely complicates the afternoon convective forecast so precip chances mainly during the afternoon may need to be adjusted a bit. Still watching potential for an MCS to move through the area tonight which would bring a damaging wind threat to the region.
Prev Disc, Multiple shortwaves will transit across the Mid- Atlantic this weekend bringing the potential for a few rounds of scattered showers and thunderstorms.
today This morning, a weak shortwave progresses across the region. Lingering instability east of hwy 17 will continue through the night, and as this shortwave clips NE portions of the CWA we could see some showers and thunderstorms from 5-10AM. If tstorms develop, 0-6km bulk shear of 15-20 knots and zonal flow aloft will work against robust convection, but MLCAPE values around 1500 J/kg and PWATs near 2.2" could result in transient cores dropping and producing gusty winds. In addition, with the weakly veering shear predominantly at the lowest levels and low LCLs a brief waterspout isn't out of the question. Overall threat for severe weather is low, but non-zero this morning.
This afternoon sea breeze develops in a hot and humid environment with plenty of instability to play with. Shear however is expected to be meager, 10-15 knots and there really is no upper level support. As a result, some isolated to scattered pulse thunderstorms are possible along the sea breeze today. While overall weak shear precludes sustained updrafts, instability is high enough where brief pulse-severe thunderstorms are possible along the sea breeze. It is worth noting that CAMs are not too excited about convection in the afternoon, suggesting a rain-free afternoon for most. Still, it really won't take much for convection to bubble up today, so maintained a chance of tstorms through the afternoon (20-40%).
A third round of convection is looking more and more likely this evening as a shortwave and MCS approaches the region from the west. Current expectation is for a shortwave to approach the region after 20Z, bringing isolated to scattered thunderstorm chances north of hwy 264. These thunderstorms will form in an area of slightly higher 0-6km shear (20-25 kts), allowing for a little bit better updraft maintenance. With deep instability and plenty of moisture still present, strong to low end severe storms would be possible with the storms initiating north of hwy 264 late this afternoon. Following these storms, a more potent MCS approaches the region around sunset. While CAMs have the MCS weakening as it moves through the region, there does seem to be a bias where they underestimate MCS maintenance. Once the MCS moves through, should it keep it's strength, the primary threat would be damaging winds. A point of consideration is with the seabreeze moving through earlier in the day, surface winds will be southerly, veering to southwesterly aloft matching the synoptic flow. This will bring some weak low level helicities into the equation as well, and while probs are low, it will be worth monitoring for a brief spin up. The MCS looks to move through the region through the first half of tonight before finally moving offshore before sunrise.
Sunday The strongest shortwave looks to impact the area on Sunday ahead of an incoming backdoor cold front. Cams suggest a MCS moving into the region along the shortwave in the evening in addition to any sea breeze convection developing in the afternoon. With better upper level support and more favorable timing compared to Saturday's MCS, this one has a shot at bringing some damaging winds as well. In fact, NCAR ML severe guidance has higher severe probs on Sunday compared to Saturday, maybe due to the better upper level support. The back door cold front looks to have slowed down a notch, now moving through overnight Sunday. Precip with the shortwave out ahead of it will likely stabilize up a bit, bringing a lower thunderstorm risk along the front. Spc has us in a marginal (1/5) risk of severe weather Sunday.
KEY MESSAGE 2, A WAA regime will persist through this weekend as high pressure becomes centered offshore. This will bring continued SSW winds and increasing low level thicknesses to ENC. Latest guidance continues to show low level thicknesses generally around 1410-1425m which support highs into the low to mid 90s each day. With temps in the low to mid 90s and dewpoints in the upper 60s to low 70s heat indices will likely peak around 100-105 today and Sunday. Will note with an increase in precip chances especially Sat/Sun. With a drier trend in CAMs for this afternoon, it is some spots see enough breaks in clouds to reach AppTs of around 105F, but this is not expected to be widespread enough or long enough of a duration to issue any headlines. Sunday will see another day of near heat advisory criteria AppTs, 100-105F thanks to the slower progression of the back door cold front. With lows only getting into the 70s each night this weekend there wont be much relief from the heat. If you have any extended plans outdoors this weekend make sure to stay properly hydrated and take proper precautions when outside.
KEY MESSAGE 3, No significant changes to the extended forecast as an omega block sets up across the Eastern CONUS with anomalous ridging persisting across the the midwest and eastern US next week. This will bring the potential for an extended period of dangerous heat to ENC starting around Wed next week and continuing into the July 4th weekend. Gefs probs of high temps > 100F have increased slightly to 30-50% for inland locales during this time period. Meanwhile, EPS probs are still near 0% through July 4rd for ENC, with better chances along and west of I-95. Nws probabilistic Heat Risk values of reaching major heat risk levels or higher are currently sitting at about 40-60% on Wed, 70-90% on Thurs, and 80-90% on Fri/Sat which is fairly notable given the higher end values this far out. Those sensitive to heat and anyone planning on spending ample amounts of time outside later next week should continue to monitor the forecast trends as this potential heat wave would have impacts on the holiday weekend. Cpc has highlighted the Carolinas in a high risk of extreme heat July 2-4.
13z Saturday through Wednesday Clusters of SHRA and TSRA will remain possible through early morning hours across NE NC as an upper level wave moves through the moist and unstable airmass in place. For now, I've focused the TSRA risk in the short-term, but trends will be monitored in case this needs to be expanded in time within the TAFs. Mvfr CIGs are developing along the coastal plain and near the coast, with PGV and ISO at sub-VFR levels right now, expected to improve by 15Z. Another round of TSRA is expected to impact ENC today. Like today, there could be multiple clusters of TSRA just about at any point in the morning or afternoon hours. Stay tuned for TAF updates and amendments as this is a low confidence forecast over the next 24 hours. Of note, TSRA that develop across the area Saturday will be capable of 40-60kt wind gusts and perhaps some hail.
Outlook (Saturday night through Wed): Could see some isolated showers and thunderstorms along the seabreeze again Sun afternoon, with a shortwave moving through Sun evening bringing better coverage of storms with it. These will be capable of bringing brief periods of sub- VFR conditions to any area impacted by this activity. A front then tracks across the area Sun night bringing better chances of predominant sub- VFR conditions. However, by Mon VFR conditions return and persist into Tue.
We have seen pretty frequent gusts up around 25 kts across Diamond Buoy and given similar atmospheric conditions across our coastal waters have elected to hoist the small craft advisories here slightly earlier today starting now. Small craft advisory still starts at 2PM across the Pamlico Sound as it may take some more time for more frequent 25kt gusts to begin occuring outside of thunderstorm activity.
Prev Disc, Moderate to breezy SSW winds will continue today, with potential for a period of 25 kt gusts developing in the afternoon and evening for the coastal waters and the Pamlico Sound. Issued Small Craft Advisories with this update, although it is more marginal with wind gusts 25-29 knots expected. What gave higher confidence to issue the product was both REFS and HREF ensembles giving a >50% chance for wind gusts over 25 knots in the SCA issued regions. In response to the increase in winds this afternoon into tonight, seas along the Gulf Stream are expected to reach 6 ft. Winds lessen a tad Sunday morning, staying SW'rly 15-20 knots with the occasional 25 knot gust possible.
Another feature of note is the potential for strong thunderstorms Saturday. In the morning hours this threat will be primarily north of Cape Hatteras, transitioning to inland rivers along the sea breeze in the afternoon, and for all area waters in the evening as a cluster of strong to sever storms moves through from the west.
Outlook (Sun through Wed): Gulf stream showers and thunderstorms possible through Sun with the shortwave and back door cold front. Winds will eventually shift from the SW to the NE on Sun and Mon from N to S behind the aforementioned front.
Nc, beach hazards statement until 8 pm EDT this evening for ncz195- 196-199-204-205. Marine, small craft advisory from 2 pm this afternoon to 11 pm EDT this evening for amz135. Small craft advisory until 11 pm EDT this evening for amz152. Small craft advisory until 11 am EDT Sunday for amz154-156.
