Unsettled weather continues today as a trough axis moves through the region. Summer-like weather arrives late this week as a ridge of high pressure builds through the weekend.
Through today As of 245 AM Thursday,
key messages
- AM thunderstorms with heavy rain and small hail possible
- Conditional risk of severe thunderstorms this afternoon and evening
Early this morning, a stout EML plume is spreading east across the Southern U.S. On the leading edge of this plume, a modest area of low-mid level WAA is supporting small clusters of elevated convection from central into eastern NC. This activity should persist through just after sunrise this morning, then wane as warming temps aloft and a strengthening cap overspread the area within the EML plume. Through early this morning, the risk of severe weather appears very low due to modest shear and instability, and a lack of stronger forcing. However, the tallest cores could produce some small hail (pea to half inch size).
After sunrise, there should be a lull in convective activity for several hours due to the stronger cap in place. However, by mid to late afternoon, heating of a moist boundary layer should lead to a gradual erosion of the cap, with most guidance suggesting an area of moderate to strong instability developing (MLCAPE of 2000-3000j/kg). Meanwhile, northwesterly flow aloft overtop south to southwest SFC winds should lead to deep layer shear increasing to 30-40kt. The overlap of strong instability and moderate shear is more anomalous for this time of year. Essentially we will be overlapping summer instability with spring shear. At face value, the shear/instability combo today is more than sufficient for severe thunderstorms, including the potential for some higher end severe weather. However, convection this afternoon and evening will be fighting against warming temps aloft and upper level ridging building in from the SW. At the SFC, forcing looks to be primarily driven by sea/bay/river breezes, as well as a weak lee trough. Aloft, a mid-level shortwave translating east out of the TN Valley may also provide some support for lift.
Short-term guidance is in generally good agreement depicting at least isolated convective development where lift is maximized. Of note, some guidance is a bit more aggressive, showing supercells upstream congealing into one or two clusters that eventually move SE towards the coast during the evening hours.
With any deep convection that can develop, and be sustained, the environment appears supportive of some higher end severe weather (large hail of golf ball size or larger, and damaging winds of 70+ mph). A low-end tornado potential appears evident as well, although higher LCLs and weaker low-level flow should keep this risk limited/more brief in nature. Lastly, should clusters of thunderstorms develop, there would be a locally enhanced wind risk.
This appears to be one of those potential high impact, but low confidence scenarios. The environment supports some higher end severe potential, but the above-mentioned limitations make it unclear whether or not deep convection can develop and be sustained. Stay tuned for updates on this potential.
Tonight As of 245 AM Thursday,
key messages
- Decreasing risk of thunderstorms tonight
Warming temps aloft and mid/upper level ridging should lead to a gradual decrease in convective coverage and intensity after midnight, and the forecast will reflect a decreasing chance of showers and thunderstorms.
Friday through Wednesday As of 0400 Thursday,
Ridging will continue on Friday with very warm temperatures arriving with a punch. Expect much of the area to battle with the lower 90s and summer- like humidity. The ridge continues to show signs of holding drier weather for Friday with PoPs retreating northward away from the ridge's periphery. With that said, instability will be building to, if not higher than, 3kJ/kg in the afternoon thanks to ample heating so showers and tstorms are not out of the question should the sea/sound/river breezes be enough to initialize.
Hot again on Saturday in downsloping flow, push highs into the lower or mid 90s with dew points still in the upper 60s. Heat indices in the upper 90s FRI, mid 90s SAT. Westerly flow intersecting the sea breeze could produce isolated storms during the afternoon with a slight uptick in rain chances during the evening as a cold front approaches the area, crossing overnight. Followed by a secondary backdoor front end of the weekend.
Quiet and relatively cool early through midweek ahead of the next vertically stacked low to dig toward the Carolinas lateweek.
09z Thursday through Monday Through 06z Friday As of 145 AM Thursday,
key messages
- Modest TSRA potential over the next 24 hours
- IFR/LIFR conditions to impact portions of ENC through early Friday AM
Isolated to scattered TSRA will continue across portions of the Carolinas overnight within a broad zone of warm air advection. The probability at any one terminal is around 20-30%, and I've opted to use PROB30 to highlight the potential (as opposed to TEMPO or prevailing groups). Stay tuned for amendments through the night in case confidence increases at any terminal. Where TSRA occur, brief reductions to VIS can be expected. The TSRA risk then becomes more conditional during the daylight and evening hours Thursday. The airmass will be sufficiently unstable for TSRA, but several limiting factors leads to lower confidence. In light of this, I removed the VCTS mention from the previous TAFs until, or if, confidence increases. Of note, if TSRA manage to develop on Thursday, there will be an increased risk of sub-VFR conditions, as well as a risk of large hail (>1" in diameter) and strong/erratic wind gusts.
Recent satellite imagery and surface observations show a narrow zone of low stratus has developed across the coastal plain of ENC, and is currently impacting KISO and KPGV. Short term guidance suggests this area of stratus will persist much, if not all, of the night, with an increased risk of IFR/LIFR CIGs. It's unclear how far east this area of stratus will reach, so for now I've opted to keep KOAJ and KEWN at VFR overnight.
Friday through Monday As of 0400 Thursday, Shower chances decrease late this week and into the weekend, but isolated to scattered coverage will be possible each day (primarily during the afternoon).
Through tonight As of 145 AM Thursday,
key messages
- Increased risk of thunderstorms this morning
- Thunderstorms risk returns this afternoon and this evening
Modest southwesterly flow of 10-20kt will be common through tonight, although a period of lighter 5-15kt winds is expected this morning. Within this flow, occasional gusts up to 25kt will be possible across the central waters and the Pamlico Sound. However, the risk doesn't appear significant enough to warrant any marine headlines. The modest southwesterly flow will keep seas elevated (3-5 ft).
Early this morning, thunderstorms are expected to be ongoing across the Pamlico Sound and nearby coastal waters. The thunderstorm risk then diminished during much of the day, before returning late afternoon into this evening. The coverage should be more scattered in nature by then. Where thunderstorms develop this afternoon and evening, there will be a risk of large hail and wind gusts in excess of 50kt.
Friday through Monday As of 0400 Thursday, Boating conditions deteriorate Saturday ahead of the next cold front to cross area waters leading to probable SCA conditions in SWerly 15-25kt winds SAT afternoon and evening. Secondary backdoor front sinks S across waters late Sunday. High pressure builds in with Nerly surge late SUN night/MON AM. Generally 10-15kt winds slowly through early week N-NEerly Tuesday becoming Eerly Wednesday as offshore high departs SEward and next low approaches from the W.
Nc, none. Marine, none.
