textproduct: Newport/Morehead City

WHAT HAS CHANGED

A Frost Advisory has been issued for the far western row of ENC counties for late tonight into early Saturday morning.

The chance of showers was slightly increased for this evening and early tonight.

Small Craft Advisories were issued for portions of the central and northern waters for late tonight into Saturday.

KEY MESSAGES

1) Scattered showers to accompany a cold front this evening.

2) Frost/freeze impacts expected this weekend.

Marine: Elevated winds and seas will continue across the waters through the weekend as a series of cold fronts push through the region.

DISCUSSION

KEY MESSAGE 1...A potent upper level shortwave will pivot through the Carolinas this evening, with an accompanying area of moderate low-mid level frontogenesis. The area of enhanced lift associated with the wave and frontal forcing will overlap with an area of moderate low-mid level moistening and steep lapse rates this evening. While moisture isn't great, short-term guidance insists on shower development from around sunset this evening to around midnight tonight. This appears to be a scenario where lift and slantwise instability should be able to overcome the lack of better moisture, and make use of whatever moisture is available. Elevated instability is forecast to be lower than last evening, therefore the risk of lightning looks to be lower. Significant rainfall is not expected with these showers.

KEY MESSAGE 2...A strong surface high will build in over the weekend and will be accompanied by a colder than normal airmass. This should support below to well below normal temperatures, both during the day and at night. Behind tonight's cold front, it now looks like there is just enough of a chance for winds to decouple well inland as lows fall into the low to mid 30s. This increases the odds for frost development, and a Frost Advisory has been issued for late tonight into early Saturday morning for the western row of ENC counties. East of there, low to mid 30s appears possible as well, but confidence in winds decoupling enough for frost formation is lower, therefore the Advisory does not include those counties.

The coldest thicknesses associated with this airmass will settle in Saturday night. With strong high pressure overhead and good radiational cooling conditions, the stage is set for lows in the upper 20s to low 30s for many inland areas away from the influence of water. A Freeze Watch remains in effect for those areas for Saturday night into Sunday morning. A Frost Advisory may be needed for some counties bordering the watch area if winds decouple enough. This weekend may end the frost/freeze program for some counties, but for the rest, some frost/freeze potential may continue into early next week as high pressure continues to support good radiational cooling conditions in tandem with cold low-level thicknesses. The airmass is forecast to moderate some, though, but probably not drastically so given a mostly unchanged synoptic pattern.

AVIATION /18Z FRIDAY THROUGH WEDNESDAY/

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

A secondary cold front will move south out of Virginia and into North Carolina over the next several hours. This front will be accompanied by an area of enhanced low-mid level lift, weak instability, and modest moisture. Similar to yesterday and last evening, another round of SCT SHRA appears likely this evening into the early portion of tonight. Where SHRA occur, brief reductions in VIS are likely, and PROB30s have been added where confidence in SHRA is the highest. For now, though, the risk of sub-VFR CIGs appears low. The front will be accompanied by a modest WNW to NW wind shift. Winds may occasionally be gusty as well, especially during the day Saturday.

Outlook: Yet another weak front/surface trough is forecast to move through late Sunday into Sunday night with a NW to NNE wind shift. This front isn't forecast to have nearly as much lift or moisture with it, and the risk of SHRA appears much lower. Otherwise, VFR conditions look to prevail into next week.

MARINE

Relatively light winds of 5-15kt this afternoon will rebuild to 15- 25kt by tonight as yet another cold front moves south through the area. The greatest risk of 25kt winds with this next surge of wind looks to be across portions of the central and northern waters, and a new suite of Small Craft Advisories have been issued to account for this. Of note, the only non-coastal waters included in the advisory for now are the Croatan and Roanoke Sounds as some funneling may enhance winds in that area. It's possible the advisory will need to be expanded west some to include other inland rivers/sounds, but guidance has been fairly consistent showing sub- 25kt winds west of the current advisory area.

For the coastal waters, seas of 3-5ft this afternoon will build to 5- 8ft across the central and northern waters, and the outer coastal southern waters. Elsewhere, seas of 3-5ft will be common.

Outlook: Modest north to northeast winds of 10-15kt, with higher gusts, will be the theme going into next week as high pressure is anchored to the north, and low pressure develops well offshore to the SE of ENC. Seas will generally be 2-4ft nearshore, and 3-5ft offshore.

MHX WATCHES/WARNINGS/ADVISORIES

NC...Frost Advisory from 3 AM to 8 AM EST Saturday for NCZ029-044- 079-090-091. Freeze Watch from late Saturday night through Sunday morning for NCZ029-044-045-079-080-090>092-193-198. MARINE...Small Craft Advisory from 1 AM Saturday to 1 AM EST Sunday for AMZ150. Small Craft Advisory from 2 AM Saturday to 1 AM EST Sunday for AMZ152-154. Small Craft Advisory from 3 AM to 7 PM EST Saturday for AMZ231.