textproduct: Wakefield

WHAT HAS CHANGED

Confidence continues to slightly increase with respect to the development of coastal low pressure Sunday into Monday. However, confidence continues to remain low with regard to sensible weather impacts, including the potential for precipitation to end as snow or a rain/snow mix Sunday night into early Monday.

KEY MESSAGES

1) Dense Fog has developed and will persist through the morning causing reduced visibilities. A cold front then crosses the region this afternoon and settles into the Carolinas Saturday as a wave of low pressure tracks along the boundary.

2) Stronger coastal low pressure likely impacts the region Sunday into early Monday but sensible weather details remain uncertain

DISCUSSION

As of 356 AM EST Friday... KEY MESSAGE 1...Fog is expected to develop through the morning causing reduced visibilities. A cold front then crosses the region this afternoon and settles into the Carolinas Saturday as a wave of low pressure tracks along the boundary.

Early morning weather analysis shows primarily zonal flow aloft across the Mid-Atlantic region and an upper level low across the Midwest. At the surface high pressure remains just off the New England coast helping to keep the stationary boundary south of the area and across central NC. Temperatures across the area are remaining in the middle to upper 40s across the area. Recent observations are showing dense fog developing causing reduced visibilities of less than a quarter of a mile across piedmont and stretching towards the coastal waters and down across NE NC. Therefore, a Dense Fog Advisory has been issued. The far western Piedmont counties along the route 15 corridor are remaining just above criteria but visibilities are remaining between 1 to 2 miles and an SPS remains in effect.

Through the rest of the morning the stationary front will begin to lift north as the high moves further off the New England coast. the fog/drizzle will continue as the warmer air will move over the shallow cool air. By the mid to late morning the cold front will continue to move into the area. Given there is enough moisture across the area rain showers are likely. Additional of .25-.5" N and 0.1" or less S are expected. Will also note that some CAMS have hinted on possible thunderstorms across the far S across portions of SE VA/NE NC. Forecast highs for today will range from the lower/mid 70s for SE VA/NE NC, mid/upper 60s for central VA, and 50s for the Eastern Shore, but these values will be lower if the low clouds take longer to scour out.

By tonight, drier air arrives and lows will drop into the middle 40s S and upper 30s to low 40s N. Additional showers are progged for Saturday as a low pressure system tracks along a stationary boundary. Clouds through the day will thicken and rain chances increase with QPF totals less than .1" across SE VA and NE NC. High temperatures will still be mild with highs in the 50s.

KEY MESSAGE 2...Stronger coastal low pressure likely impacts the region Sunday into early Monday but sensible weather details remain uncertain.

Model guidance for the system Sunday has come into slightly better agreement on a vigorous upper trough and strengthening coastal low pressure off the Mid-Atlantic coast. The confidence on the low pressure system forming remains high but there continues to remain some uncertainty on exact weather impacts. The 00z ECMWF and CMC favors the system as rain and ending with snow across central VA to the Eastern Shore as colder air get wrapped around. In addition, the probabilities have increased for 3" of snow with both the CMC and ECMWF showing 50-60% across the Eastern Shore and 40 to 50% across the Northern Neck. Snow accumulation is possible on elevated and grassy surfaces, especially across the Eastern Shore and Northern Neck. Timing for this system has not changed much and is expected Sunday night and ending during the day on Monday. Will also note, rain and snow, gusty winds are possible, especially along the coast.

Looking past this storms a blast of colder air will move back into the area keeping temperatures below average through the first half of the week. Then by the end of next week temperature s look to moderate ahead of an additional cold front.

AVIATION /18Z FRIDAY THROUGH WEDNESDAY/

As of 1250 PM EST Friday...

A stationary front lingers from SE VA into northern NC as of 18z. Meanwhile, a cold front is pushing E across the Blue Ridge. Widespread IFR/LIFR cigs persist along and N of the stationary front, but are beginning to show some signs of improvement, and this trend should continue through 20-21z. A few brief showers are possible through 20z, but should have minimal impact on vsby. The wind is gradually shifting to SW, but there is a shift to NW immediately behind the quasi-stationary boundary, before the flow shifts back to SW. VFR conditions are expected to prevail tonight through Saturday with a light W/WNW wind of 5-10kt. Low pressure passing S of the region Saturday will bring additional mid and high level clouds along with a 20-30% chc of light rain across southern VA/NE NC.

Outlook: Strong low pressure develops off the coast Sunday into Monday and this has the potential to bring another period of rain, gusty winds, and flight restrictions to the region Sunday into early Monday. Precipitation could end as a rain/snow mix or all snow at SBY and RIC. Drier air and high pressure will bring a return to VFR conditions later Monday, which continues through Wednesday.

MARINE

As of 200 AM EST Friday...

Key Messages:

- Marine Dense Fog Advisory has been expanded to include the Chesapeake Bay and tidal rivers.

- A Small Craft Advisory has been issued for the coastal waters north of Cape Charles Light due to elevated seas to 5 feet.

- A stronger system impacts the waters Sunday into early next week. Gale conditions are possible across the coastal waters and potentially the Chesapeake Bay.

Early this morning, a backdoor cold front remains stalled just south of the waters. Winds are currently E to NE around 5 to 10 knots. Seas are averaging ~4 to 5 feet over the northern waters and 3 to 4 feet south. Marine fog has temporarily improved compared to earlier, but expect visibilities to diminish again from south to north this morning as the front gradually moves back to the north. A Marine Dense Fog Advisory has been issued for the Chesapeake Bay and tidal rivers until 10 AM as visbilities have started to diminish. A Marine Dense Fog Advisory also continues until 10 AM for the coastal waters south of Cape Charles Light and the Currituck Sound. Will monitor visibilities for a potential expansion of the advisory. Otherwise, a Small Craft Advisory has been issued for the coastal waters north of Cape Charles Light due to 5 foot sea potential (especially out 20 nm) this morning into this evening. The front is forecast to lift back northward later today with sub-advisory winds becoming S and SW ahead of the trailing cold front then becoming westerly tonight into early Saturday.

A stronger system develops near the coast Sunday and moves out to sea on Monday. There still remains significant disagreement in regards to low strength and track, with the GFS depicting a strong (~980 mb) low closer to the coast while the ECMWF and Canadian keep the low farther offshore. Regardless of specific model details, potential for Gale conditions continues to increase with local wind probabilities showing 50-80% probs of 34 kt gusts in the coastal waters and 30-50% in the Chesapeake Bay. Gale Watches will likely be needed later today or tonight if models begin to converge toward the stronger solution.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Dense Fog Advisory until 1 PM EST this afternoon for ANZ630>638-650-652-654-656-658. Gale Watch from Sunday evening through Monday afternoon for ANZ630>632-634-650-652-654-656-658. Small Craft Advisory until 7 PM EST this evening for ANZ650- 652-654.