textproduct: Newport/Morehead City

WHAT HAS CHANGED

No significant forecast or messaging changes.

KEY MESSAGES

1) Localized severe threat for coastal areas this afternoon

2) A thunderstorm risk, some potentially severe, Monday afternoon east of HWY 17

3) Reduced thunderstorm risk possible Tuesday and Wednesday, with unsettled weather returning by late week

DISCUSSION

KEY MESSAGE 1...A cold front will translate east across North Carolina today, then stall along the coast as frontal forcing weakens and shifts NE well away from the region. It still appears that the combination of the seabreeze and the stalled front will support an area of enhanced low-level convergence focused right along the immediate coast. Forcing will be aided by a shortwave moving through the area and jet entrance region dynamics. Meanwhile, and area of modest mid-level lapse rates will overspread a moist boundary layer characterized by dewpoints in the 70s in the vicinity of the front. Heating of this airmass should yield moderate to strong instability with MLCAPE of around 2000 j/kg. While low-level flow is forecast to be weak, modest mid-upper level flow should support deep layer shear of 25-30k, favoring organized multicells. While the front will be slightly removed from the strongest shear, short-term guidance suggests the potential for a few rotating updrafts/loosely organized supercells.

While drier air aloft will help support DCAPE of 1000j/kg+ and an increased potential for strong downdrafts, it may also impact the sustenance of deep convection. That said, the setup appears supportive of at least a few longer-lived cells capable of damaging winds. If any sustained rotating updraft can develop, there could also be a risk of hail. While the convective risk should primarily be diurnally-driven, the front in the area plus plenty of elevated instability may allow a low-end thunderstorm risk through the night.

KEY MESSAGE 2...Guidance is in good agreement depicting a weak surface low lifting northeast along a front that should be stalled along the coast of the Carolinas on Monday. In fact, as the low lifts through, it may pull the front back to the west slightly. Once again, moderate to strong instability is forecast to develop along the front with MLCAPE around 2000 j/kg. One potential difference on Monday is that deep layer shear may get a slight boost along the track of the surface low. This may open the door for a slightly improved potential for a few loosely organized supercells. At minimum, it should support a continued risk of organized multicell clusters. With the front potentially getting pulled west some, the convective risk may also expand west some and not be confined to the coast only. That said, it still appears that the greatest risk of strong to severe thunderstorms will be east of HWY 17. The Storm Prediction Center has added a marginal severe weather risk for our eastern counties. Once again, the primary risk looks to be damaging wind gusts. But, any rotating updraft will be capable of some hail.

KEY MESSAGE 3...Guidance has been waffling some on whether or not the airmass can fully dry out Tuesday and Wednesday as the Sunday/Monday front may still be stalled nearby. While the convective risk may not completely drop off, it looks like it may be reduced for a day or two. Moisture and instability then begin to rebuild across the Southeast U.S. coastline with the potential for another round of unsettled weather.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

Forecast confidence is moderate to high over the next 24 hours.

Despite a somewhat drier airmass moving into the area, there has still be enough support for an area of low stratus and BR/FG from central into eastern NC early this morning. The greatest impact is expected to the west of ENC, but may briefly impact KOAJ, KISO, and KPGV. A drying westerly flow should lead to a fairly quick mixing out of any low CIGs/reduced VIS by 13z.

During the day today, a cold front will move into the area and then stall. Guidance is in good agreement with the front stalling along the coast, which should keep the TSRA risk just east of the TAF sites. It may be close for KOAJ and KEWN, but given the reduced risk, the PROB30s have been left out for both sites for now.

Outlook: A front will remain stalled along the coast of the Carolinas through at least Tuesday. The front may get pulled west a bit on Monday and Tuesday as a couple of lows ride north along it. This would up the TSRA risk some, especially from KOAJ to KEWN. A risk of sub-VFR conditions would accompany any TSRA risk as well.

MARINE

A cold front will move into ENC today, then stall across the area over the next couple of days. A couple of weak areas of low pressure are then forecast to lift northeast along the front today and Monday. This should continue to favor periods of thunderstorms. The background flow is expected to be the strongest early this morning (SW at 10-20kt). The gradient will then relax some as the front moves in and stalls. Varying wind directions are expected as the pair of lows move through, but neither low looks all that strong.

For the coastal waters, seas of 2-4ft are expected today, highest this morning. Seas of 2-3ft are then expected on Monday.

Outlook: Winds will become northeasterly for a brief time on Tuesday before southerly flow returns by the middle of the week, and lasting into the end of the week. Seas should generally hold around 2-3ft through Thursday, then build to 3-5ft late in the week. The risk of thunderstorms may decrease some Tuesday and Wednesday before increasing again later in the week.

MHX WATCHES/WARNINGS/ADVISORIES

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