Marine Weather and Tide Forecast for South Mills, NC

KEY MESSAGES
1) Cold and dry weather prevails through Wednesday, with Tuesday being the coldest day. Temperatures potentially moderate some Thursday.

2) Chances for impactful winter weather continue to increase this weekend. Exact details remain unclear at this time, but users should keep a close eye on the forecast this week.

DISCUSSION
As of 240 PM EST Monday...

KEY MESSAGE 1...Cold and dry weather prevails through Wednesday, with Tuesday being the coldest day. Temperatures potentially moderate some Thursday.

A deep-layer trough will remain situated over the eastern CONUS through Tuesday. At the surface, cold Canadian high pressure gradually builds down from the northern Plains into the MS Valley, eventually settling over the area Wednesday. A reinforcing cold front pushes through tonight, with additional CAA overspreading the region. The coldest temperatures of the week are then expected Tuesday as another trough slides through and 850 mb temps bottom out around -9 to -14C. Temps have trended a couple degrees "warmer" for tonight, with upper teens-lower 20s in most areas (mid teens possible N/NW). With a light NW wind, wind chills are progged to drop to 10-20 F for most of the area, with 5-10 F possible in the Piedmont on the MD Eastern Shore. Highs Tuesday may struggle to get above freezing across far northern parts of the FA, with mid-upper 30s elsewhere. It'll actually be colder (widespread mid teens with localized lower teens) Tue night as the high settles overhead.

The upper flow turns more zonal for the middle of the week. This should allow temps to moderate into the 40s Wednesday and then 50s by Thursday. A series of weak cold fronts will move through Wednesday night and again Thursday night. While these will be mainly dry (as the best forcing remains N and NW of us), cannot completely rule out a light rain shower on Thursday. Cooler temps return for Friday behind these fronts, but the coldest air doesn't arrive until the weekend.

KEY MESSAGE 2...Chances for impactful winter weather continue to increase this weekend. Exact details remain unclear at this time, but users should keep a close eye on the forecast this week.

The impressive medium range signal for impactful winter wx from deterministic/ensemble guidance for the past day remains in place.
Wintry precipitation may start as early as Sat AM. However, it must be stressed that uncertainties remain regarding the exact precipitation evolution. Details below.

A very strong push of low-level CAA arrives Saturday with 850-925mb temps dropping to -10 to -15 C across a decent portion of the area as 1045mb+ Arctic high pressure builds into the Midwest. Highs will struggle to get out of the 20s on Sat except across far SE VA/NE NC.
In fact, most of the guidance shows temps staying below freezing through the entire weekend (and into Monday) across our entire area except SE VA and NE NC. Regarding moisture, the upper pattern appears quite favorable for an active storm track and a significant winter event, with a strong Alaskan ridge, an active/amplified southern stream over the S/SW CONUS, and the aforementioned troughing to our N. There is increasing agreement among most model guidance and ensembles on an expansive precip shield blossoming in the central/southern Plains on Friday, expanding ENE into the Deep South and TN Valley by Saturday as a strong subtropical jet expands NE and strengthens. This precip will overrun the very cold airmass, likely leading to a large area of wintry precip across the central and southern CONUS. For us locally, there remains several uncertainties with respect to timing and p-type, though the deterministic and ensemble guidance remains consistent in showing an impactful winter wx event for our area. As mentioned above, precip could begin as early as Saturday AM. The most likely time for snow/sleet/freezing rain looks to be from late Saturday through Sunday (potentially lasting into Sunday evening). Both deterministic models and ensemble guidance show a moderate-high likelihood for 0.5- 1.0" of liquid equivalent precip with this event. The main question seems to be whether we see snow, sleet, or freezing rain. With the strong high/impressive Arctic airmass building in, think p-type would be freezing or frozen everywhere except for maybe southside Hampton Roads and NE NC (and it could very well be mostly snow here as well depending on storm track).

While the Canadian and GFS ensembles trended slightly north, the ECMWF/EPS trended a bit south with the 12z/19 run. Ensemble probs for at least 1.0" of liquid equivalent are 30-70% across the area (which is quite impressive). Ensemble snow probs from the GEFS/EPS (including from the AI ensembles) are 30-60% for 6"+, with lower probs from the CMCE which gives us more sleet and freezing rain.
Probs for freezing rain are highest from the NC/VA border and points S. These chances are likely to waver back and forth some over the next few days as the finer details become clearer. In summary, there is increasing confidence in a widespread winter wx event for our area which could bring significant impacts. Exact details regarding precip timing, coverage, and type remain uncertain and should be resolved over the next few days. Stay tuned!

Wintry precip aside, there is high confidence in very cold air spilling into the region for the weekend into early next week. Could certainly see widespread lows in the single digits Monday AM. Should any snow cover be present, some areas could see 0F readings!

AVIATION /06Z TUESDAY THROUGH SATURDAY/
As of 1245 AM EST Tuesday...

VFR conditions prevail today with just some passing mid-high clouds early this morning as a cold front moves through the region. Light W-SW winds shift to the NW early this morning as the boundary pushes through. WNW winds around 10 kt are expected this afternoon with occasional gusts to 20 kt. SKC skies and calm winds tonight.

Outlook: Mostly dry/VFR through Thursday. A cold front potentially crosses the area Thursday with only a 20% chance of showers at this time. Low-end precip chances continue into Friday. Winter weather is possible at all terminals this weekend, but it is too early for specifics.

MARINE
As of 240 PM EST Monday...

Key Messages:

- Small Craft Advisories are in effect this afternoon into early Tuesday AM as another strong Arctic cold front approaches and crosses the waters.

- Generally sub-SCA conditions are then expected through the mid week timeframe.

- A stronger storm system potentially approaches the waters late in the week into the weekend.

Afternoon analysis shows the arctic cold front just west of the area. The pressure gradient ahead of the front remains weak at the moment and winds are continuing to remain out of the SW between 10 to 15 kt with some gusts upwards of 20 kt. Seas are remaining between 1 to 2 ft across the bay and 3 to 4 ft across the ocean zones. Through the rest of the afternoon and into tonight the pressure gradient will tighten slightly allowing winds to increase out the SW initially before switching to the NW once the front passes tonight. Winds will increase to 15 to 20 kt with gusts upwards of 25 kt ahead and briefly behind the front with the initial surge of colder and drier air. Seas will increase with seas between 2 to 3 ft across the bay and 4 to 5 ft across the ocean. Small Craft Advisories will continue to remain in effect for all waters minus the upper rivers through early Tuesday morning. In addition, cannot rule out at least the potential for some freezing spray tonight, mainly for the far northern coastal waters and Chesapeake Bay.

High pressure will then move into the area diminishing the winds Tuesday morning. Benign Marine conditions will continue through much of the week. However, a brief surge in southerly winds is possible Wednesday night into early Thursday AM. By this weekend, there is the potential for a much stronger system that will bring elevated SCA and low end Gale conditions and perhaps freezing spray across the waters. Recent local wind probs have jumped to 40 to 50% of wind gusts >= 34 kt. Given the cold air potentially moving into place it is quite reasonable for these probabilities. There still remains uncertainty in the strength but the potential is there for elevated marine conditions.

AKQ WATCHES/WARNINGS/ADVISORIES
MD...None.
NC...None.
VA...None.
MARINE...Small Craft Advisory until 4 AM EST early this morning for ANZ630>634-650-652-654-656-658.