textproduct: NWS Wilmington

WHAT HAS CHANGED

Freezing fog advisory in affect for a portion of the region.

Introduction of rain and/or snow to the forecast for the upcoming weekend. Confidence is very low at this point.

KEY MESSAGES

1) Dangerous driving conditions tonight into Monday morning due to patchy black ice and freezing fog inland.

2) Wind chills could require a Cold Weather Advisory Monday and Tuesday nights.

3) Winter mix is possible Saturday and Sunday.

DISCUSSION

KEY MESSAGE 1: Dangerous driving conditions tonight into Monday morning due to patchy black ice and freezing fog inland.

Standing water paired with the dropping temperatures tonight could lead to patchy black ice formation. Current observations are showing fog for several of our inland counties paired with near to below freezing temperatures. Have put out a Freezing Fog Advisory until the morning, but mixing is possible before dawn that may lower the coverage of fog. Will continue monitoring through the night.

KEY MESSAGE 2: Wind chills could require a Cold Weather Advisory Monday and Tuesday nights.

The combination of well below normal temperatures (in the low to mid 20s tonight and lower 20s Tuesday night) and light wind will lead to wind chill values 15 to 20 degrees. While the likelihood of Cold Weather Advisories being needed is decreasing the possibility still exists, especially Tuesday night.

KEY MESSAGE 3: Winter mix is possible Saturday and Sunday.

A cold front will move in from the north-northwest late in the week and stall in the region. The front ends up parallel to the flow aloft, but where the front ends up stalling remains very uncertain. The location of the front and the shallow, unseasonably cold air on the northern side of the front will be the key to the forecast. If the front ends up stalled to the north of the local area, the event will end up all rain. If the front stalls in the forecast area the potential for freezing rain increases with snow becoming possible if the front pushes south of the forecast area.

The strength of the high behind the front and the location/strength of a 5h low over southern CA/Baja will be important factors to monitor the next several days. The high will determine how far south the Arctic air extends while the 5h low enhances the stream of Pacific moisture over the southern CONUS and sends several shortwaves across the Southeast. It is possible that a combination of all 3 scenarios play out if the front slowly sags south across the forecast area. Uncertainty remains high and thus confidence is very low. Do have some concerns that the shallow nature of the cold air will end up leading to more of an ice (sleet/freezing rain) event instead of a snow event. For now will carry a rain/snow forecast but, significant changes should be expected as the details become clearer.

AVIATION /06Z MONDAY THROUGH FRIDAY/

Some restrictions tonight as fog sticks around inland and some low stratus moves along the coast. The stratus/low could threat for coastal terminals has come to an end though some SCT/FEW IFR clouds could stick around until the morning. The larger threat will be freezing fog at inland terminals. Some mixing is possible ~09Z so will have to continue monitoring trends in the VSBYs, for now have put out a Freezing Fog Advisory for inland areas. Conditions should clear up 13-14Z with west winds ~5-8 kts and VFR, calm winds after sunset.

Extended Forecast...VFR likely through Wednesday. Restrictions may return with another frontal passage Thursday and Friday.

MARINE

Through Tonight... West winds ~10-15 kts. Seas 2-3 ft with a weakening wind wave at 1-2 ft and 3-4 seconds and a SE swell at 7-8 seconds.

Tuesday through Friday... Week will follow a pattern of a cold front followed by northerly winds for a day which veer to southerly before the next front arrives. Front will be exiting to the southeast Tue morning with the next front slated for later Thu. While winds do briefly touch a solid 15 kt during the week in the post front regimes do not see the need for any headlines through Fri. Seas 2-3 ft with occasional 4 ft possible at times. Seas will be a mix of a persistent southeast swell and a wind wave varying from northerly post front and southerly just ahead of the front on Thu.

ILM WATCHES/WARNINGS/ADVISORIES

NC...Freezing Fog Advisory until 8 AM EST this morning for NCZ087. SC...Freezing Fog Advisory until 8 AM EST this morning for SCZ017- 023-024-032. MARINE...None.