textproduct: Newport/Morehead City

WHAT HAS CHANGED

Short term models show lower precipitation chances for Wednesday as a weakening shortwave approaches the area. There will still be a brief period during the afternoon where pop up thunderstorms will be possible.

Continued this trend with the evening update by lowering PoPs some as well as blending in some fresher guidance into QPF grids to show the spottier coverage.

KEY MESSAGES

1.) A couple of shortwaves will bring chances for rain Wednesday and Thursday afternoons. There is a Marginal Risk of severe thunderstorms storms on Wednesday afternoon.

2.) More rain chances arrive this weekend as a low pressure system develops off of the southeast coast on Saturday and drags a frontal system through the area Saturday night.

Marine: Elevated seas will continue to bring SCA conditions across the coastal waters north of Ocracoke Inlet into tonight. Low end SCA conditions possible Wednesday night into early Thursday for portions of the coastal waters.

DISCUSSION

KEY MESSAGE 1...For the rest of today, a weakening shortwave will bring cloud cover to the area with a very small chance of precipitation before our focus turns to the next wave. On Wednesday, a low pressure system will move out of the mid-Mississippi Valley and push northward through the Ohio Valley, guided by a weak upper level trough. Short term models are showing much more meager rain chances and may keep eastern portions of the area dry till afternoon or later. In a similar theme, instability driving any potential convection looks to stay well below 500J/Kg until very late in the afternoon/early evening. While we remain in a Marginal Risk across the entire forecast area, western portions of the area could realize more of the instability during the afternoon hours with eastern areas more towards sunset.

Following in its footsteps, another shortwave will move off of the SC/GA coast on Thursday. Models show it somewhat disorganized and our forecast area on the northern fringe of any precipitation or convective activity. PoPs generally reside in the slight chance to low chance regime which is lower than Wednesday.

KEY MESSAGE 2...Turning attention to the weekend, our next chance for significant rainfall to try and eat into the persisting drought over the area will be on Saturday as a low pressure develops off of the southeast coast and works its way over eastern NC. As this is happening an upper level low centered over Ontario and Quebec will work to deepen an upper level trough that will begin to push a supporting wave out of Texas which will eventually elongate into the frontal system that will accompany the coastal low. The merged systems will push through Saturday night into Sunday and move offshore but not before some significant rainfall with at least the southern half of the area having a 50% chance of at least an inch of rainfall.

As far as convection is concerned, currently most of the instability remains offshore but strong deep layer shear could help sustain any convection that initiates. Still a lot of uncertainty in the models regarding how strong the low will get and will have to monitor as the system gets closer.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/

VFR flight cats will hold for the remainder of this evening and early tonight. Previous forecast called for the potential development of patchy fog across interior ENC as the low levels become saturated overnight with light to calm winds. Occasional mid and high based cloud cover will likely limit the fog from becoming dense, and generally 4-5 miles MVFR level fog is expected at this time overnight into early tomorrow morning. This evening's model suite is not excited about this potential and probabilistic guidance suggests SChc (generally less than 25% chance) of this happening with little consensus about where fog may develop. Have converted the prevailing MVFR VIS lines to 6sm MIFG with TEMPO groups for all terminals (now including EWN as well, which was omitted in 18Z TAFs). VFR flight cats return soon after sunrise, but CIGs will be lowering through the morning as rain showers approach from the W in advance of a frontal system. MVFR CIGs will likely develop early to mid afternoon as rain and thunderstorm chances increase with blended guidance suggesting IFR is possible. Have introduced SCT IFR decks WED afternoon/evening to show this possibility.

Outlook: MVFR conditions will continue tomorrow night until showers and thunderstorms exit off the coast, and then VFR is expected through the rest of the work week. Winds generally in the 5-15 kt range through the period. Another low pressure system may bring widespread rain for the weekend and a return to sub VFR conditions.

MARINE

Based on latest guidance, have extended the Small Craft Advisory for the northern waters to 9z Wednesday for seas of 6 feet. This is mainly for outer portions of the 20 nm zone as areas closer to shore should remain under the 6ft threshold.

Current observations showing easterly winds around 15 kt or less with seas around 3-5 ft in most areas. Winds will become variable today as high pressure transits the area, becoming southerly late tonight but should remain less than 15 kt.

Outlook: A low pressure system is progged to pass north of the area Wednesday night and could see low end SCA conditions over the nearshore coastal waters S of Oregon Inlet redevelop late Wednesday afternoon night into Thursday. Another low pressure system may pass across or just south of the waters late in the week which could bring another chance for small craft advisory criteria to be met.

MHX WATCHES/WARNINGS/ADVISORIES

NC...Beach Hazards Statement until 8 PM EDT this evening for NCZ203- 205. MARINE...Small Craft Advisory until 6 AM EDT Wednesday for AMZ150. Small Craft Advisory until 8 AM EDT Wednesday for AMZ152-154.