textproduct: NWS Wilmington

WHAT HAS CHANGED

Updated 00Z aviation discussion.

KEY MESSAGES

1) Above normal temperatures slated for Sat through Mon before much cooler temperatures arrive following a strong cold frontal passage late Mon.

2) There is a marginal risk (threat level 1 of 5) of severe storms Saturday evening over NW areas.

DISCUSSION

KEY MESSAGE 1...Above normal temperatures slated for Sat through Mon before much cooler temperatures arrive following a strong cold frontal passage late Mon.

KEY MESSAGE 1 DESCRIPTION...Upper ridging to prevail Sat thru Sun and flatten-some Mon. Sfc pressure pattern and gradient to yield SW winds thru the period. Expect widespread 80s for max temps thru the period. with a somewhat pinned sea breeze Sat and Sun, keeping temps in the low to mid 70s at the beaches. MOS Guidance paints mid to possibly upper 80s Sun/Mon with aid coming from subsidence and a downslope trajectory in the wind field in the low to mid levels. Ie. Involving some compressional heating. Flow aloft flattens-some Mon into Tue, allowing a sfc cold front, accompanied by isolated showers and tstorms to push thru late Mon. Only isolated in coverage due to the limited moisture available. Cool, dry and strong high pressure ridging ridging in from the NE States will follow Tue into Wed. At or slightly below normal temps to follow as a result.

KEY MESSAGE 2... There is a marginal risk (threat level 1 of 5) of severe storms Saturday evening over NW areas.

KEY MESSAGE 2 DESCRIPTION... Daytime Saturday should remain dry across the area with the column remaining fairly dry and no organized lifting mechanism. A ribbon of higher moisture glides into the area Saturday evening along with weak mid-level shortwave energy moving in from the WNW. This will spark some isolated to widely scattered showers and thunderstorms over NW areas. Widespread severe weather is not anticipated, in part due to the fairly low rain chances, but there is a marginal risk of large hail with any storm due to steep mid-level lapse rates near 7 C/km in association with cool temps aloft.

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

VFR. High clouds are starting to move across the area where they'll stay for the majority of the period. S winds will turn more SW tonight with speeds staying ~8 kts. The major restriction will be LLWS due to a 35-40 kt SW/W LLJ forming around 09Z and lingering until sunrise. Winds become more westerly by Saturday afternoon where another sea breeze could form but it may stay pinned to the coast due to the stronger offshore flow. With their proximity to the coast MYR/CRE will see a turn to southerly winds probably ~20-22Z with more uncertainty for ILM, maybe closer to 23Z.

Extended Forecast...VFR to dominate. A cold front will move through Mon with the chance for isolated restrictions due to tstorms and possibly some sea fog along the coast before the front moves through. VFR then returns through Wed.

MARINE

Through Saturday...High pressure to slide off the coast and offshore this afternoon. Light and variable wind direction will become southerly 5 to 10 kt this aftn, with the hier end of the range nearshore due to an active but weak sea breeze into this evening. The sc pg to tighten tonight into Sat as a weak cold front drops south, stalling across NC, just north of the local waters. Looking at SW winds increasing to 15 to 20 kt tonight into early Sat with a SW'erly LLJ overhead. The cool stable marine layer, above low to mid 50s SSTs, will prevent the majority of those winds from mixing down to the ocean sfc. SW to W winds will diminish-some Sat due to a relaxed-some sfc pg due to the cold front in close proximity. Could even observe a pinned decent southerly sea breeze Sat aftn/evening. An E-ESE 10 second period 2 to 4 ft swell will dominate the seas spectrum this aftn into this evening. SW wind chop may equalize the power between the 2 later tonight into Sat but as the winds diminish- some Sat, the 10 second period swell will prevail, except nearshore where a Sat afternoon/evening sea breeze will produce wind chop.

Saturday Night through Wednesday... Sub-SCA conditions continue this weekend with broad sfc high pressure positioned off to the south. A SCA is then likely Monday night into Tuesday as N/NE winds gust up to 25-30 kt following a cold fropa. Improving marine conditions thereafter as sfc high pressure builds in. Seas mainly 2-4 ft through Monday increase up to 5-7 ft with the front Monday night and Tuesday.

ILM WATCHES/WARNINGS/ADVISORIES

NC...None. SC...None. MARINE...None.