Key MESSAGE 1, A potentially significant severe weather event is taking shape across parts of ENC this afternoon into early evening. Spc has all of ENC under an Enhanced Risk (level 3 of 5) with best chances of severe likely across interior zones. Overall the upper level pattern remains the same, with an impressive upper level trough digging south through the OH Valley and continuing E'wards today while taking on a more negative tilt as it moves E'ward towards the Ern Seaboard. At the surface, strong surface low (sub 990mb) will track NE'wards across the Great Lakes and Interior Northeast while its associated strong cold front tracks across the Carolinas through the day pushing offshore tonight. Severity of T'storms will depend on cloud cover today and amount of destabilization through this afternoon. More Sun = more instability while more clouds = less instability.
Dynamics increase today as strong 60-70 kt llj develops invof eastward advancing cold front and aforementioned deepening low. Strong albeit mainly unidirectional shear today in the range of 30-50 kt, combined with skinny ML CAPES approaching 1000 J/KG inland, with closer to 300-500 J/KG coastal counties due to marine layer, will lend to a damaging wind threat with any storms that can become organized. Semi discreet clusters this afternoon may produce an isolated tornado threat, while bowing line segments will produce a threat for damaging wind gusts up to 70 mph given the strong llj dynamics in place. Strongest shear and instability will be concentrated along and west of Hwy 17, and this is where REFS props are highest for a higher end (60-70 mph) severe potential.
Moving into the early evening hours, one final round of precip will occur associated with an organized line of showers and some embedded thunderstorms along the strong cold front. Instability will be waning with loss of daytime heating, though gusty winds may still accompany convection along the main line along the quickly eastward advancing cold front. Precip sweeps quickly offshore with the cold front prior to midnight.
With the aforementioned strong wind field in place, gusts of up to 50 mph still possible for the OBX and Donweast Carteret, though even remaining adjacent coastal counties will see wind gusts of 40-45 mph this afternoon, and may eventually need to be upgraded to a wind adv if winds come up a bit more than expected. High Surf Advisory remains in effect through Mon with beach erosion and ocean overwash remaining a concern for vulnerable locations susceptible to S'rly wave directions.
KEY MESSAGE 2, The initial blast of CAA directly behind Mon's front will lead to MinTs in the 30s, though above freezing as atms will be mixed with ongoing CAA. Arctic high pres builds in Tue through Thu. The afternoon's CAA and the center of the high settling almost directly overhead late Tue night/early Wed will lead to clearing skies and calming winds. These conditions will prime the FA for strong radiational cooling effects, leading to MinTs well down in the 20s for mainland areas, with 30s DownEast, beachfront, and OBX nearer the warmer waters. Another subfreezing night Wed night with high pres still nearby. As a result any planting that has been done given our recent stretch of warm weather should take proper precautions to protect plants and any outdoor pipes before we warm Thursday and beyond.
06z Monday through Friday Challenging forecast through the overnight, but the good news is IFR flight cats unlikely the majority of the TAF cycle. Current obs show cloud bases range from FL015-040, but sky cover ranges from FEW to OVC in highly transient clouds racing generally from S to N in strengthening LLJ. Expecting terminals to bounce in and out of MVFR FL010 Outlook, Pred VFR conditions will return by late Monday night behind the front. Winds turn NWerly but fall off drastically speedwise. Uneventful reinforcing cold front crosses through TUE and high pressure dominates the forecast through the remainder of the work-week, keeping VFR flights cats in place. A strong cold front is forecast to cross from W to E tonight. Strong srly gradient develops today with gale gusts for all marine area of ENC, and thus expanded gale warnings for all zones, mainly due to afternoon mixing coinciding with strongest wind field and gusts exceeding gale gusts even on the inland rivers and sounds. In addition to the strong background wind field, a risk of strong to severe thunderstorms mainly in form of gusty winds expected through early this evening before winds diminish towards midnight as cold front sweeps eastward and offshore. Guidance continues to show patchy dense sea fog developing across the northern waters this evening and continuing into the first part of Monday, as dewpoints increase combined with onshore flow. However the warmer SST's over the last couple of weeks and strengthening wind speeds will limit sea fog concerns. Outlook: Winds become N-Nerly mid-week behind TUE's reinforcing front remaining generally 5-15G20kt through the remainder of the work week. Sea-driven SCAs likely to remain active into Wed morning, continuing to improve through late week. Low pressure system well offshore late week expected to increase swell and could further the need for extending SCAs that follow the Gales MON and TUE. Nc, high surf advisory until 2 am EDT Tuesday for ncz196-204-205. Wind advisory from 2 pm this afternoon to 10 pm EDT this evening for ncz196-204-205. Marine, gale warning from noon today to 10 pm EDT this evening for amz131-136-137-230-231. Gale warning from 2 pm this afternoon to midnight EDT tonight for amz135. Small craft advisory until 4 pm EDT this afternoon for amz150. Gale warning from 4 pm this afternoon to midnight EDT tonight for amz150. Small craft advisory until 6 am EDT early this morning for amz152-154. Gale warning until midnight EDT tonight for amz152-154. Small craft advisory until 10 am EDT this morning for amz156- 158. Gale warning from 10 am this morning to midnight EDT tonight for amz156-158. Marine
Watches, Warnings, Advisories
