Key MESSAGE 1, Cold front is slowly making its way eastward across NC this hour per satellite and surface observation analysis, forecast to stall along the coast as overall forcing weakens and shifts away from the region. Starting to see some gradual aggravation of cu fields along the immediate coast with enhanced convergence ahead of the frontal boundary and along diurnal sound and sea breezes. Some additional lift is being provided by a weak shortwave pivoting around deep mid-level troughing swirling over the eastern CONUS.
Pre-storm environment today appears marginally favorable for strong to severe storms with MLCAPEs climbing to 2500-3000 J/kg and deep layer shear, especially in the vicinity of the boundary layer, of around 30-35 kt. Multi-cell clusters are the favored storm mode today but a few weak supercells are not out of the question. Healthy amount of dry air aloft and forecast DCAPEs of 1000+ J/kg point to damaging winds once again being the main threat, but in supercells some rotating updrafts could support some hail and a low risk of a tornado. The convective risk should primarily be diurnally-driven, but some overnight redevelopment of showers and storms is possible as the front will remain in the area, and elevated instability will remain abundant. Overall moisture is not as deep as the past few days and the overall flooding threat is comparatively lower.
Guidance continues to depict a weak surface low lifting NE along the frontal boundary tomorrow (the low may actually subtly pull the boundary farther inland as it progresses). Overall pre-storm environment will be similar to tomorrow, sans a modest uptick in effective shear in the vicinity of the low. This may provide a marginally better environment for supercell development. If the front does get pulled west, the convective risk will also follow suit. The greatest risk of strong to severe thunderstorms remains east of HWY 17 with damaging winds remaining the primary threat, with hail possible in supercells.
KEY MESSAGE 2, Guidance still struggling on whether or not the airmass can fully dry out Tuesday and Wednesday as our current frontal boundary may still be stalled nearby. Isolated showers and storms cannot be ruled out but coverage is likely to be far sparser than the past few days. Moisture and instability then begin to rebuild across the Southeast U.S. Coastline with the potential for another round of unsettled weather.
18z Sunday through Friday High confidence in VFR conditions through today with moderate confidence overnight. Today's main focus is surface cold front moving into the area from the west, then stalling near the coast. Sound and sea breezes will be the main focal point for convective activity, which will pose a low risk (10-20%) for KEWN and KOAJ. Based on satellite trends, PROB30 remains omitted for these terminals.
Light winds and clear skies tonight will be present tonight but modestly drier air raises uncertainty on fog and low stratus coverage. At least some isolated coverage appears probable but will hold off on including in TAFs until rainfall footprint and near time moisture trends.
Outlook: A front will remain stalled along the coast of the Carolinas through at least Tuesday. The front may get pulled west a bit tomorrow and Tuesday as a couple of lows ride north along it. This would up the TSRA risk some, especially from KOAJ to KEWN. A risk of sub-VFR conditions would accompany any TSRA risk as well.
A cold front approaches area waters this afternoon, stalling across the area over the next couple of days. A couple of weak areas of low pressure are then forecast to lift northeast along the front tonight and tomorrow, favoring periods of thunderstorms in the overnight and early morning. Varying wind directions are expected as the pair of lows move through, but neither low looks all that strong.
For the coastal waters, seas of 2-3 ft are expected today through tomorrow.
Outlook: Winds will become northeasterly for a brief time on Tuesday before southerly flow returns by the middle of the week, and lasting into the end of the week. Seas should generally hold around 2-3ft through Thursday, then build to 3-5ft late in the week. The risk of thunderstorms may decrease some Tuesday and Wednesday before increasing again later in the week.
Nc, none. Marine, none.
