Marine Weather and Tide Forecast for North Shore, VA

NEAR TERM /THROUGH MONDAY/
As of 530 PM EST Sunday...

Key Message:

1) Lows tonight in the 20s/teens will promote refreezing of snowmelt, resulting in black ice & slick spots on some roads.

Evening update adjusted temperatures to fit current observations, which were slightly higher than forecasted.
Otherwise, the previous forecast remains on track with cold and dry conditions continuing through the overnight hours.

Previous Discussion...

Key Messages:

1) Lows tonight in the 20s/teens will promote refreezing of snowmelt, resulting in black ice & slick spots on some roads.

2) Light snow showers in the mountains of WV Monday.

High pressure currently overhead shifts to the southeast tonight. A front tracks in from the northwest Monday with limited moisture but decent upslope to overall bring a dusting to an inch of snow over the mountains of western Greenbrier County, southwest toward Burkes Garden. May see flurries as far south and east as I-81 and the NC mtns. Winds with this system will be typical run of the mill with gusts 20-25 mph Monday afternoon.

Temperatures will continue to drop quickly now that the sun has set, on their way to lows in the mid teens to the low 20s.
Falling temperatures will cause snowmelt to quickly refreeze, resulting in black ice and slick spots on area roadways. Clear skies early in the night will give way to increasing clouds toward dawn as a cold front nears the Appalachian chain from the west.

Southwest to west flow ahead of the front and sunshine will allow temperatures to warm well above freezing for most areas outside the mountains Monday, which should allow for more snow melt. Highs will range from the 40s in the Piedmont to 30s in the mountains.

SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/
As of 100 PM EST Sunday...

Key Messages:

1. High confidence for sub-zero wind chill values in the mountains Wednesday morning.

2. High probability for winds greater than 30 MPH in the mountains Tuesday and Tuesday night.

3. Accumulating upslope snow expected in western Greenbrier County Tuesday into Tuesday night.

While there still some minor differences among the deterministic models with regard to the strength of the upper level shortwave that pass through our area Tuesday night, the individual ensemble members are in good agreement that the coldest temperatures and lowest wind chill values will occur Wednesday morning with a 70-90% chance some locations in the mountains will see wind chill values below zero.

In the wake of this surge of colder air arriving, strong pressure rises and cold air advection will produce gusty winds, especially in the mountains, where there is high confidence gusts will exceed 30 MPH. The NAM snow squall parameter output suggests the best potential for snow squalls will be north of our forecast area, but with some positive CAPE reaching southeast WV by Tuesday evening, this potential cannot be ruled out.

Upslope snow showers Monday night in the wake of the first frontal passage should quickly wane as drier air arrives, but by Tuesday late afternoon/evening upslope snow showers will return and continue into Wednesday morning, bringing advisory level accumulations to western Greenbrier County. Some of these snow bands may bleed into southwest VA.

Generally followed the NBM for temperatures during this period, but did lower minimum temperatures a few degrees from the NBM Wednesday morning.

LONG TERM /THURSDAY THROUGH SUNDAY/
As of 200 PM EST Sunday...

1. There is lower than normal confidence regarding the timing and type of precipitation Friday night into Saturday.

2. High confidence for a warming trend Thursday and Friday.

Rising 500mb heights resulting in shortwave ridging over our region by Friday will bring warmer temperatures with the NBM showing a 100% chance of above freezing temperatures Friday for all areas except Western Greenbrier county and the highest elevations spots like Peaks of Otter and Mt. Rogers.

Confidence in the forecast falls Friday night and Saturday as the the individual ensemble members of the 12Z GEFS show a significant spread the timing and type of precipitation that begins sometime Friday night or Saturday. With a deep southwest flow and increasing amplitude of the upper air pattern in advance of the approaching system, leaned toward the slower arrival time of the precipitation and lowered POPS Friday night.

This pattern also would favor a mixed precip type or rain during the onset.

Confidence is increasing in another surge of very cold air arriving sometime Sunday night or early next week, but the GEFS show a very wide range of expected temperatures during this time.

AVIATION /00Z MONDAY THROUGH FRIDAY/
As of 530 PM EST Sunday...

Expect VFR conditions to continue areawide through early Monday morning. As a cold front approaches from the west, it will likely bring MVFR cigs to BLF/LWB/BCB, and possibly lower cigs to IFR conditions in BLF/LWB terminals. BCB clears out and returns to VFR late afternoon, while BLF/LWB will likely remain in MVFR conditions through the end of the period. A few light snow showers or flurries will be possible Monday afternoon/evening at BLF/LWB through the end of the period.

Wind speeds will generally be light and from the west to southwest into Monday morning, then begin to gust to 20kts in the mountains by 18z from the west lasting through the end of the period.

AVIATION OUTLOOK...

Looking at sub-VFR ceilings Monday afternoon for BLF/LWB and BCB, with spotty light snow showers occasionally reducing visibilities, as another cold front passes across the central Appalachians. Mainly VFR conditions are expected further east.

Another cold front will arrive Tuesday, supporting the potential for sub VFR conditions across the mountains.

Widespread VFR for the latter half of the workweek, but another system may bring poor flying conditions by next weekend.

RNK WATCHES/WARNINGS/ADVISORIES
VA...None.
NC...None.
WV...None.