textproduct: Wakefield

WHAT HAS CHANGED

Little change to the forecast through the weekend and into next week.

KEY MESSAGES

1) Dry with seasonable temperatures today and Saturday. Breezy conditions develop this afternoon. A few showers are possible Sunday afternoon, but otherwise remaining mild along the coast, warmer inland.

2) A strong cold front approaches early Monday, crossing the region late Monday through Monday night. Strong to severe storms are possible ahead of and along the front, with below normal temperatures to follow Tue-Wed.

DISCUSSION

As of 330 PM EDT Friday...

KEY MESSAGE 1...Dry with seasonable temperatures this weekend today and Saturday. Breezy conditions develop this afternoon. A few showers are possible Sunday afternoon, but otherwise remaining mild along the coast, warmer inland.

High pressure has moved well offshore of the mid-Atlantic coast this aftn, but is still ridging back into the Carolina coast. A strong sfc low (989 mb) is situated across northern lower Michigan, and the pressure gradient in between these features, along with dry air and deep mixing, has led a a breezy to windy aftn for the local area. It is mostly sunny, with just some high clouds and temperatures generally in the 50s (upper 40s eastern shore). A weakening cold front drops SE tonight, and pushes into the area early Saturday. Mostly clear tonight with enough mixing to keep temperatures milder; lows will mostly be 40-45F. Slightly warmer on Saturday with less wind and highs mainly in the 60s (upper 50s eastern shore). Low pressure deepens considerably over the central CONUS on Sunday with increasing temps and humidity across the local area. A few showers are possible for far southern portions of the area late Sunday afternoon but PoPs do not increase substantially until Sunday evening into the overnight hours.

KEY MESSAGE 2...A strong cold front approaches early Monday, crossing the region late Monday through Monday night. Strong to severe storms are possible ahead of and along the front, with below normal temperatures to follow Tue-Wed.

12z models remain in decent agreement depicting a strong mid/upper level trough taking on a negative tilt, almost becoming cutoff across the western Great Lakes by Monday aftn/evening. At the sfc, intense low pressure is forecast to lift NE from the mid MS Valley to the western Great Lakes late Sun night/early Mon. Models show this low deepening to 980mb or lower and then occluding as the surface and upper level features stack vertically. Latest GFS/ECMWF/GEM is in very good agreement considering the time range, and continues to show a deepening sfc trough along the Appalachians on Monday which would likely keep the sfc/boundary layer winds due S or perhaps even backing to the SSE ahead of the cold front. Strong deep layer shear will be in place due to impressive wind fields aloft and would be augmented further by any degree of low level backing from the developing surface trough. Instability is still more uncertain with most models showing widespread clouds and showers ahead of the front, which could limit surface heating. However, strong southerly flow will advect increasing low level moisture into the region ahead of the front with dew points expected to be well into the 60s. Strong kinematics aloft and forcing along the cold front will promote a mainly linear convective mode across the region with strong straight line winds likely the primary threat. Given the degree of deep layer shear and potential for increasing low level shear, supercells well out ahead of the cold front will be possible during the day Monday, with a QLCS developing right ahead of and with the frontal passage Monday evening. Tornadoes are a possibility in both of these regimes. SPC Day 4 Outlook has 30% highlighted for most of the CWA, with 15% for the eastern shore (where some degree of onshore flow would tend to limit instability a bit more). Have highlighted the HWO for the website in the 30% region for now.

The airmass behind this system will be much cooler (actually trending to well below normal Tue-Wed) as well as significantly drier. Highs mainly in the 40s Tue- Wed. Most of the area can expect a hard freeze Tue night/Wed AM as strong >1030mb sfc high builds overhead, with diminishing winds and lows ranging through the 20s. Even the coast will likely see at least a light freeze with lows in the upper 20s to lower 30s, the possible exception being the NC OBX. Gradually trending warmer by late in the week, and remaing dry.

AVIATION /19Z FRIDAY THROUGH WEDNESDAY/

As of 200 PM EDT Friday...

VFR across the region this aftn, with high clouds and S winds gusting to 20-30 kt, highest N and inland. Winds will gradually drop off this evening, but will still be elevated at ~15 kt with highest gusts this evening. SW to WSW LLWS is highlighted at all terminals tonight, primarily from 00-06Z well inland, and a few hrs later closer to the coast as a strong LLJ of 40-50kt moves through. Winds shift to the WNW Sat, and will be a bit breezy at SBY, generally 10 kt or less elsewhere.

Outlook: VFR conditions persist into Sunday. Shower chances increase late Sunday/Sunday night, with flight restrictions possible into early Monday. A strong cold front will bring the potential for additional flight restrictions and potentially strong to severe TSRA Monday. Even outside of any storms, strong, gusty southerly winds prevail into Mon evening. Dry/VFR Tue with breezy WNW winds, remaining dry Wed with less wind.

MARINE

As of 230 PM EDT Friday...

- Small Craft Advisories are in effect north of the VA/NC border this afternoon into tonight in advance of a weakening cold front.

- A strong cold front approaches from the west Monday and crosses the coast Monday night. Small Craft Advisory conditions are likely with gale conditions possible. Additionally, strong thunderstorm wind gusts are possible.

High pressure is centered just to the SE offshore this afternoon. A low pressure system (~988 mb) is currently centered over the Great Lakes region, moving eastward towards New England, pushing a weak cold front across the local waters tonight. Winds have already increased this afternoon as the pressure gradient tightens between the two systems. Winds are currently SSW around 15-20 kt with gusts to 25 kt across the Ches. Bay and coastal waters north of the VA/NC border (5-10 kt, gusts to 15 kt south). Waves are around 1 ft with seas 2-3 ft. Winds will likely peak later this afternoon and evening to 20-25 kt with gusts to 30 kt in the coastal waters north of the NC border and the Ches. Bay and 15-20 kt with gusts to 25 kt in the rivers (possible for the Lower James to see gusts to 30 kt). A brief period of gusts to 34 kt is possible in the coastal waters this evening, with local probs showing about a 50% chance. Given the southerly wind direction, SST in the 40s, and marginal confidence, will issue SMWs for 34 kt gusts if needed, rather than a Gale Warning. Waves and seas will additionally build late tonight/early Saturday morning to 3-4 ft waves and 4-6 ft seas north of the VA/NC border and 3-4 ft south. Small Craft Advisories are in effect through late this evening.

Sub-SCA conditions will return by daybreak Saturday into Saturday night, as the cold front with the low pressure system brings very little CAA with its passing. High pressure will build to the NE, but a stronger low out of the Midwest will move towards the Great Lakes, pushing a warm front across the local area Sunday, which may lead to SCA conditions with ESE winds. Then, a stronger cold front will pass through the region Monday evening. High-end SCA conditions are likely, with a period of gale conditions possible in southerly flow ahead of the front and WNW flow immediately behind the front. Additionally, there is a risk for strong thunderstorm wind gusts ahead of the front. Seas will build to 5-7 ft S to 7-10 ft N Monday into Monday night, with 3-5ft waves in the Ches. Bay and locally higher at the mouth of the Bay. More benign marine conditions are expected by the middle of next week as high pressure settles across the region.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 4 AM EDT Saturday for ANZ630>632- 634-650-652. Small Craft Advisory until 10 PM EDT this evening for ANZ635>637. Small Craft Advisory until 1 AM EDT Saturday for ANZ638-654- 656.