textproduct: Newport/Morehead City

WHAT HAS CHANGED

SCA has been expanded to cover coastal waters S of Ocracoke Inlet through Surf City. Timing of pre-existing SCA for central coastal waters has been adjusted.

Today and FRI have trended drier.

KEY MESSAGES

1) A cold front will move through Thursday, bringing gusty winds and scattered to numerous showers and thunderstorms. Isolated storms may become strong to severe.

2) High pressure will build in Friday and bring a brief round of generally dry conditions.

3) Another front will move through early next week, with increasing shower and thunderstorm chances.

DISCUSSION

KEY MESSAGE 1...A positively tilted upper-level trough will move across the Midwest THU, becoming neutral to slightly negatively tilted over NE CONUS THU night. At the surface, a slow moving cold front will move into ENC, pushing S of the FA by THU night. Timing differences still in place across avail HiRes guidance due to development of weak lows along the boundary upstream. Depending on the depth of these waves, FROPA could start as early as THU morning in the Nern FA, or as late as THU evening. These timing differences could have significant impacts on T/Td, Max temps, and available instability for storm development.

THU, moisture convergence from Sern stream system over SWern CONUS and the approaching system to the N will be aided by weak areas of SFC low pressure along the front upstream will lead to an increase in clouds and rain chances after midnight tonight into the early morning hours THU. Forcing is expected to be relatively weak locally with greater dynamics and stronger jetting N of the FA. However, there is still a low, but non- zero, chance for some storms to be strong to marginally severe with ample bulk shear building through the day, albeit mostly speed shear which would favor more multi-cellular storm-modes. Instability available for convection associated with FROPA will depend heavily on the coverage of showers and thunderstorms early and the exact timing of the front. Current QPF for 6Z THU-6Z FRI ranges from 0.25-1" with highest totals over NWern zones of the FA. In addition to showers and storms, Thursday will bring gusty SW winds with gusts to 20-25 mph inland and 25-35 mph along the coast. Storms with greatest vertical development may mix down some of the stronger winds aloft, making strong wind gusts the greatest threat for the area.

KEY MESSAGE 2...Surface high pressure will briefly build in on Friday leading to a mild, mostly dry day with MaxTs in the low 70s. The high shifts offshore FRI night ahead of a shortwave to move through the Carolinas Saturday. This will lead to warmer, cloudier conditions to start the weekend with moisture advection ramping up in the Serly flow developing on the W side of the high.

KEY MESSAGE 3...Rain chances increased again later SUN into MON ahead of another front and wave of low pressure that is currently forecast to cross the FA through the day MON. Right now it looks like another potential high shear/low CAPE setup, so will continue to monitor the potential for stronger storms.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

VFR conditions and breezy SW winds will continue through this evening, with cigs gradually lowering overnight and early Thu morning. CIGs likely falling to MVFR conditions late tonight. Additionally, increasing large- scale lift should lead to a gradual increase in the risk of SHRA and TSRA, especially from KISO to KPGV. Will continue to leave thunder out for now due to uncertainty with how much instability will be present. A cold front will slide south through ENC on Thursday with a continued risk of showers and thunderstorms. Additionally, there will be a risk of IFR CIGs (40-60% chance), mainly after 14z. A northerly wind shift will occur along the front by early afternoon.

Outlook: Drier air moving in behind the front should support improving aviation conditions late Thu night and Fri morning. Looking ahead, the next opportunity for sub VFR conditions looks to be over the weekend, with the risk of showers and storms.

MARINE

Latest obs show SSW winds at 5-15kt inside, 10-20kt offshore with choppy seas 2-3 ft@5-6sec. Moderate to gusty SSW winds will continue as a slow moving cold front approaches and finally crosses THU. Light showers possible over Gulf Stream waters during peak heating today. Have added a SCA for coastal waters S of Ocracoke Inlet to the already existing central waters SCA for the strengthening winds reaching criteria this afternoon. SW winds will increase to 15-25 kt with gusts to 25-30 kt tonight into Thu, building seas to 5-7ft coastal waters, 7-9ft offshore waters. Showers and storms likely ahead of the front THU.

Outlook: Winds will veer to the NW Thursday night behind the front with seas peaking at 5-8 ft. Winds will decrease to 15-20 kt with gusts to 20-25 kt by Friday morning with good boating conditions returning by the afternoon as high pressure builds in. The improvement will be short lived with showers and storms expected again SAT with troughing traveling over regional waters behind the high pressure sliding further offshore. Another brief lull expected early SUN before conditions deteriorate yet again ahead of a front to cross early next week.

MHX WATCHES/WARNINGS/ADVISORIES

NC...None. MARINE...Small Craft Advisory from 5 PM this afternoon to 5 AM EDT Friday for AMZ152-154. Small Craft Advisory from 8 PM this evening to 2 AM EDT Friday for AMZ156-158.