textproduct: Wakefield

WHAT HAS CHANGED

Chance of thunderstorms across the west today. SPC has added a Marginal Risk of severe weather.

Slight Risk of Excessive Rainfall has been added across the northwest on Tuesday.

KEY MESSAGES

1) Chance for showers and storms returns today and Monday as a slow- moving front moves in.

2) Persistent onshore flow and a potentially strengthening coastal low will create a wetter, cooler, and breezier forecast for most of the week.

3) Widespread minor to moderate tidal flooding (inundation of 1-2 feet AGL in vulnerable areas) is possible by the middle of the week due to strong northeast winds.

DISCUSSION

As of 315 AM EDT Sunday...

KEY MESSAGE 1...Chance for showers and storms returns today and Monday as a slow-moving front moves in.

Early morning surface analysis shows an area of high pressure over New England with a stationary front to our south along the NC/SC border. To the west, there is also an MCS moving into West Virginia. Here locally, a deck of low to mid level clouds has overspread the northern half of the area keeping temperatures fairly steady. To the south under the clear skies, temperatures have been able to fall into the mid to lower 60s. The cloud deck is trying to dissipate in spots, with thicker coverage persisting north of Richmond. Low temperatures will be able to cool off another couple of degrees, especially in the cloud breaks. The aforementioned stationary front will pick up northward momentum this morning as it becomes a warm front and pushes through our area. Winds will become south/southwesterly ushering the additional humidity and moisture back in. A cold front will also be moving through the Ohio River Valley towards our northern CWA by late this evening. The primary forecast change for today is a slightly better chance for scattered showers and storms. The best chance will be across the west/southwest this afternoon, where SPC does have a Marginal Risk of severe weather for the threat of damaging wind gusts. Hi-res guidance can't quite decide how far east they want to bring the chance for storms with some being more aggressive. This is partly due to the uncertainty of how the WV/OH MCS will fair as it crosses the mountains. For now, kept slight PoPs across the far western tier of counties. Another chance for rain will come to northern locations this evening into the early overnight as the front drops in. Some shower activity could linger into the overnight hours. With the southerly flow behind the warm front, temperatures will be able to jump into the upper 80s for most everyone, with lower to mid 80s on the Eastern Shore. Possibly our last widespread 80s for the foreseeable forecast period?

On Monday, a broad area of high pressure will settle into the Hudson Bay/Great Lakes Region. The cold front certainly won't be in a hurry to make its way through our CWA, potentially taking all day to reach the NC border. This will create quite a gradient in temperatures for Monday. For those north of the front, generally Richmond and north, highs will top out in the upper 70s to lower 80s. South of the front, mid to upper 80s will once again make their presence known. Our far southern NC localities could even approach 90 degrees. Don't fret though because the forecast for the rest of the week looks much cooler. If the front does change its timing at all, this will affect the temperature forecast. There will also be a threat for showers and storms with the front over the area throughout the day on Monday. Per usual, best chance for storms would be south of the front where the better instability will be. SPC has a Marginal Risk of severe weather west of I-95, with the main threat still being damaging winds. WPC has removed the Marginal Risk of Excessive Rainfall for a good portion of the CWA, with western counties maintaining a risk of localized flash flooding. Rain may continue into the overnight period thanks to that lingering front. Lows will be in the lower 60s for the north and upper 60s for the south.

KEY MESSAGE 2...Persistent onshore flow and a potentially strengthening coastal low will create a wetter, cooler, and breezier forecast for most of the week.

The forecast for the rest of the week will be highly dependent on the location and strength of a developing low pressure off the coast. With the large high pressure parked to our north, we will be entering a prolonged period of onshore flow. A Cold Air Damming set up looks likely for us Tuesday into Wednesday, though it isn't quite as strong as what models were portraying the last few days. It will still greatly impact our temperatures, particularly across the north where highs will be in the upper 60s to lower 70s on Tuesday. Southeastern locations will be able to warm into the upper 70s to lower 80s as the CAD type set up doesn't quite reach. Winds will begin to increase on Tuesday as well, with coastal areas seeing gusty conditions by the evening and potentially lasting all the way into at least Friday. Again, this all depends on the location of the developing coastal low. Model guidance is a bit further offshore with its center tonight, but still strong enough to bring us quite the list of impacts. Rain chances will persist each day next week, with WPC placing us in a Marginal Risk of Excessive Rainfall each day. They have introduced a Slight Risk for the northwest on Tuesday. Guidance does keep trying to develop localized areas of significant rainfall totals off and on through the period, so keep in mind that some instances of flash flooding may be possible as those rain chances remain.

Some guidance is even showing a secondary surface low developing off our coast later in the week, which would prolong the period of impactful weather even longer. Cooler temperatures with highs in the mid 60s across the NW and lower 70s for the SE will be the trend for most of the week. Overnight lows could even dabble with the lower 50s late week. Regardless, this coastal low will bring impactful weather to our area for an extended period of time. Locations along the coast will see the biggest impacts as coastal flooding will be likely due to persistent strong onshore flow (see Key Message 3 below). It won't be good beach weather either as large waves and strong winds will lead to elevated rip current risks, as well as the risk for potential beach erosion. Model differences and timing limitations are still creating some uncertainty in the details, so please stay tuned to the latest forecast as we work out the details.

KEY MESSAGE 3...Widespread minor to moderate tidal flooding (inundation of 1-2 feet AGL in vulnerable areas) is possible by the middle of the week due to strong northeast winds.

Strong northeast winds are expected from Tuesday night through at least Thursday, which will cause water levels to rise across much of the area (especially along the bay, tidal rivers, and Atlantic coast). No tidal flooding is expected through Tuesday. A significant rise in tidal anomalies is forecast on Wednesday. Minor tidal flooding is possible as early as the Wednesday morning high tide cycle, with minor to moderate flooding forecast during the Wednesday evening high tide. This corresponds to inundation of 1-2 ft AGL in vulnerable areas. Specifics will become more clear as we get closer. The highest water levels will likely occur along the south/west side of the Ches Bay, tidal York/James, and Atlantic coast. The minor to moderate tidal flooding potentially persists through several tide cycles as NE winds remain elevated.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

As of 630 AM EDT Sunday...

Mid to low level clouds continue to linger across the area this morning. Terminals remain VFR, but some pockets of MVFR are still possible for the next few hours. Light ESE wind this morning will shift to the S/SSW at 8-10 kt after 14Z. ORF may turn more easterly this afternoon due to sea-breeze influence before becoming SSW again late. Skies will be FEW-SCT throughout the day (less clouds across the SE), with additioanl cloud cover moving in overnight. Isolated SHRA/TSRAs are possible across the far west and north this afternoon/evening, but confidence is low in any terminal impacts.

Outlook: A stronger cold front slowly crosses the region Monday into Tuesday bringing a more unsettled pattern with degraded flight conditions through at least mid-week. Coastal terminals may also have elevated northeasterly winds for an extended period.

MARINE

As of 315 AM EDT Sunday...

Key Messages:

- Mainly sub-SCA conditions are forecast through the weekend.

- SCA level winds are forecast by Monday night/Tuesday. Confidence in a period of gales with NE winds continues to increase from Tuesday night-Thursday, with the strongest winds likely occurring from Wednesday-Thursday. This will lead to significant to potentially dangerous marine conditions with 10-13+ ft seas.

Sub-SCA marine conditions prevail through the rest of the weekend with conditions deteriorating as we head through the week. Early morning marine observations show SE winds of 10-15 kt and ~4 ft seas. Winds are expected to veer to the S by this aftn before veering to the SW by tonight, while remaining in the 10-15 kt range.

Confidence is high in a significant pattern change this week. A stronger front will initially cross at least the northern half of the marine area on Monday, potentially making it to the VA-NC border. Winds will become NE and could increase to near 20 kt with gusts to 25 kt by Monday evening (best chances north). The front then may stall for a bit Monday night into the first part of Tuesday before advancing south across the entire marine area Tuesday into early Tuesday evening. NE winds are progged to increase to 20-25 kt south/25-30 kt north by Tuesday evening as stronger CAA ensues. A few gale force gusts are possible north of Parramore Island as early as late Tue aftn.

An impressive 1040mb high will build across eastern Canada by the middle of the week as low pressure deepens a couple hundred miles offshore of the VA/NC coast. This will help strengthen the CAA and tighten the pressure gradient over the local waters. The strongest winds are still expected to occur on Wednesday-Thursday as the strong high remains anchored over southern Quebec and the offshore low continues to gradually deepen. The global models are in better agreement with respect to timing, and confidence in frequent gale force gusts is now high with local wind probs showing a 70-100% chc of 34+ kt wind gusts from Wed aftn through a good part of Thu. While prevailing gusts are generally forecast to be in the 35-40 kt range, a ~6 hour period of sustained gales with 40-45 kt gusts is possible across the ocean and mouth of the Ches Bay during this time. This will lead to significant to potentially dangerous marine conditions from late Tuesday night through Thursday due to the strong winds and 10-13+ ft seas. While it is too early for Gale Watches, expect these to eventually be issued for most of the marine area as the event gets closer. Solid SCA level winds will likely continue through the end of next week as the low potentially lingers offshore. Of course, the exact timing and placement of the synoptic scale systems are not locked in place yet, but models continue to come into better agreement regarding the general pattern. We will continue to monitor the trends as this gets closer in time.

There is a moderate rip current risk for all beaches today and Monday from onshore flow. Dangerous surfing conditions are likely by the middle of the week with the prolonged onshore flow. Localized beach erosion is possible from mid to late next week as well depending on how things evolve.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...None.