Key MESSAGE 1..High pressure has shifted offshore, with southerly outherly onshore flow beginning in earnest today. Atmospheric profile to gradually moisten today, although we should still be too dry aloft for any convection to form along the sea breeze. While rain chances are still below 15% today, there should be more cloud cover along and ahead of the sea breeze coinciding with peak heating. Otherwise seasonable temps forecast today as highs reach the upper 80s to near 90s inland, and mid 80s along the coast.
KEY MESSAGE 2, ENC once again enters into a period of unsettled weather starting on Sunday. An upper trough will be deepening over the Ohio Valley Sun morning as it moves towards the Eastern Seaboard, while at the surface an associated closed low is expected to traverse the Great Lakes region. As these features move east, they will encounter the Bermuda high which is expected to stall this upper trough, surface low, and its associated fronts before they reach the Eastern Seaboard. While the upper trough stalls, embedded shortwaves rounding the base of the trough are forecast to advect into the Carolinas Sun through at least Mon/Tue. These features, in addition to the sea breeze each afternoon/evening, will be the main forcing present for a notable increase in precip chances.
There will be two areas of focus for shower and thunderstorm activity on Sunday. The first will be Sun morning along and behind a N'ward moving warm front/coastal trough with much of the activity occuring near and east of Hwy 17. We should still be too dry aloft inland as the boundary moves through, so thunder chances remain low inland Sunday morning. Proximity to the gulf stream could allow isolated to scattered showers and thunderstorms to reach coastal communities south of Oregon Inlet. The second will be in the afternoon/evening with shower and thunderstorm activity coming in from the west associated with the stalled upper trough. Cloud cover will play a big role in how high instability can truly get, but with the dewpoints rising there should be enough instability entering the region for 1000-2000 J/kg of MLCAPE Sunday. While shear is not too impressive with the unidirectional SE flow, the combination of long, skinny CAPEs, PWATs over 2", and slow storm motions could result in heavy rainfall rates and wet microbursts where storms develop. The best coverage is expected to be to our west closer to I-95, with more isolated to scattered coverage hinted at by CAMs along our coastal plain. As a result, have trended down a tad with PoPs Sunday PM with this update. Further reductions to PoPs may be necessitated with future updates if this trend holds.
Monday the trough is still stalled to our west and gradually weakens. This reduces the potential for height falls over the region despite the trough creeping a bit closer. Still, we should see some weak embedded shortwaves moving through aloft. Slightly better forcing, paired with another day of long skinny CAPEs and PWATs north of 2" brings higher precip chances compared to Sunday with heavy rainfall rates and a low end wet microburst threat and slow storm motion vectors. All this brings flash flooding concerns to mind, especially with how much rain has been observed in many locations in the past 1-2 weeks. We are currently in a Marginal (level 1/5) Excessive Rain Outlook for Sunday. What prevents it from being higher is likely the uncertainty on instability with antecedent cloud cover and the lack of substantial ground-level forcing. With high temps forecast to only be in the low to mid 80s Monday, the sea breeze may be weak in nature.
Beyond Monday, the trough/low is still expected to linger to our west until eventually it gets picked up and shifted to our north by another trough moving through the Great Lakes region. As a result, daily elevated precip chances continue through mid-week with a low end risk for flash flooding.
06z Saturday through Wednesday Pred VFR conditions expected through the TAF period with mainly diurnal Cu through peak heating. Another morning with calm winds and clear skies allowing for good radiational cooling but HREF and REFS probs for vsbys less than 5SM continue to show less than 15 percent during the pre-dawn hours. Given there hasn't been fog the past couple of nights it likely will not materialize. S to SW winds will be a bit stronger this afternoon with gusts around 15-20 kt possible. Periods of MVFR may develop early Sunday morning as a warm front/coastal trough moves through the region. Coastal regions could see isolated to scattered thunderstorms Sunday morning along and behind the coastal trough.
Outlook (Sunday through Wednesday):Periods of sub-VFR may develop Sun into early next week as ENC enters into a more unsettled period of weather with daily chances for showers and thunderstorms with a stalled upper trough off to the west. Precip chances and thus the threat for sub- VFR conditions look to decrease beyond Wed.
Benign boating conditions continue across our waters today as latest obs show widespread southerly 5-10 kt winds and 2-3 ft seas. Winds strengthen to 10-20 knots through tonight, shifting from SE'rly this evening to S'rly early Sunday morning behind a coastal trough/warm front. As wind increas, seas build to 3-4 ft tonight. Scattered showers and thunderstorms likely starting early Sunday morning along and behind the front.
Outlook (Sunday through Wed): Southerly winds will strengthen Sunday to 15-25 kts with gusts up to 25-30 kts ahead of an approaching front. Seas will also respond building closer to 4-7 ft across the coastal waters bringing an increasing chance of SCA conditions to much of our waters Sun into Mon. In addition to this, increasing chances for showers and thunderstorms will be possible as well starting Sun. Winds/seas begin to ease later Mon night into Tue with weak high pressure building overhead and aforementioned front dissipating to the west.
Nc, none. Marine, none.
