Key MESSAGE 1, Heat and humidity will build into ENC from the north and west Friday into the weekend. High impact heat and humidity is expected, as the peak of it will be during the busy 4th of July holiday weekend (Saturday through Monday) with highs expected to reach well into the 90s inland, possibly reaching 100 in some locales, with upper 80s to mid 90s beaches. The combination of the heat and humidity will push heat indices towards the 105-110 degree range or slightly higher this weekend. Overnight lows will also be warm due to the increased Tds, with MinTs around 80 near the coast, and mid 70s interior. Heat index values remain just below advisory criteria through this afternoon. A Heat Advisory has been issued for the bulk of ENC for FRI, only locations not included in the advisory are Hatteras and Ocracoke Islands, and immediate coastal zones of the Crystal Coast, where the seabreeze circ is expected to keep advisory criteria just out of the forecast, but MaxAppTs in these zones will still be hot, low to mid 90s. An Extreme Heat Watch has been issued for SAT in zones generally N of HWY70 where MaxAppT values reach into the 110-115deg range. Another Heat Advisory WILL be needed for the Holiday and remain probable SUN through MON, possibly lingering into TUE of next week.
NWS probabilistic Heat Risk values peak Saturday into Monday in the major range with some extreme risk areas inland Sunday and Monday. The chance for extreme heat risk remains similar Sunday through Monday with probabilities peaking around 40-60% across northern sections and 20-40% south with the compounding days and little relief during the nighttime periods. Those sensitive to heat and anyone planning on spending ample amounts of time outside this weekend into early next week should monitor the forecast trends.
With the ridge of high pressure building in, a cap will develop with little to no shower or thunderstorm relief through Saturday. The ridge begins to break down Sunday but guidance has backed off with extent of late day showers and storms to less than 15 percent.
KEY MESSAGE 2, Return to a pattern of increased shower and tstorms chances next week. A series of shortwaves, inland troughing, and a very slow moving backdoor front will eventually cross the FA mid-week leading to a diurnally driven, summer- time PoP forecast through much of the long-term period. Tue currently has the highest PoPs (50-70% TUE afternoon) when moisture peaks ahead of the front and a pair of shortwave troughs aloft traverse NECONUS.
18z Thursday through Tuesday Pred VFR conditions through the TAF period. Cannot rule out shallow ground fog developing in some locations again late tonight but it should have little impact to operations and dissipate quickly after sunrise. Winds will generally be light with the sea breeze developing this afternoon with winds around 5-10 kt. Have added 6sm MIFG for terminals where forecast calls for winds to decouple tonight, and have added TEMPO MVFR fog groups for EWN and OAJ. Rinse and repeat forecast for FRI; light winds early with some diurnal cu until the seabreeze rolls through.
Outlook (Friday through Monday): Dry weather is expected to prevail with pred VFR conditions through Sunday, but could see patchy fog and low stratus each morning. Winds will be light through the period with high pres in vicinity. Upper ridge breaks down Monday with shortwave energy bringing increasing chances for showers and thunderstorms and sub-VFR conditions.
Latest obs show E-SE winds 5-10 kt with seas 2-4 ft. Similar conditions expected through tonight with SE-S winds less than 15 kt and seas around 2-4 ft.
Outlook (Friday through Monday): The Bermuda high remains dominant into the weekend with light winds 5-15 kt and seas around 2-3 ft. Bermuda high pulls offshore late Sunday into Monday with a front slowly dropping south across the Mid- Atlantic serving to tighten gradients a bit and expect winds to increase to around 10-20 kt and seas building to 2-4 ft.
Nc, heat advisory from noon to 8 pm EDT Friday for ncz029-044>047- 079>081-090>092-094-193-194-198-203. Extreme heat watch from Saturday afternoon through Saturday evening for ncz029-044>047-080-094-193. Marine, none.
