textproduct: Wakefield

WHAT HAS CHANGED

Updated discussion. Temperatures have trended cooler for Saturday, with minimal fire WX concerns. Also on Saturday, added patchy/areas of fog on the Ocean N of Cape Charles and along the Atlantic coast of the eastern shore.

KEY MESSAGES

1) Still warm for most areas, but with limited fire weather concerns expected through Saturday, much cooler for the eastern shore Saturday, with fog possible along the coast.

2) Showers are likely Sunday, but areal average rainfall amounts look minimal. Fire WX concerns return next Monday in the wake of the cold front, especially if rainfall amounts are minimal.

3) There is the potential for patchy frost and even localized freezing temperatures for inland areas Monday night into Tuesday morning. Then temperatures begin to increase through the middle of the week.

DISCUSSION

As of 345 PM EDT Friday...

KEY MESSAGE 1...Still warm for most areas, but with limited fire weather concerns expected through Saturday, much cooler for the eastern shore Saturday, with fog possible along the coast.

The latest weather analysis depicts an upper level trough moving east towards the coast this aftn, pushing offshore by early evening. A few light showers passed through the FA this morning, with some residual SCT-BKN cloud cover this aftn. Temperatures are mostly in the low-mid 80s with dew pts in the 50s. Winds become light/variable this evening and overnight, with lows mainly in the upper 50s to low 60s. By early Sat morning, onshore flow develops in response to high pressure over Atlantic Canada ridging SW into the Delmarva. Could see some low clouds and even fog into the eastern shore as we approach sunrise Sat. Temperatures have trended cooler along the coast for Sat due to the onshore flow, while remaining very warm well inland. Expect to see a 30F or greater range in high temps between the MD coastal eastern shore (highs struggling to get out of the 50s), with highs in the upper 80 to lower 90s in the piedmont. While it will be dry with low RH well inland, winds do not look particularly strong, so Fire WX concerns are not enough for any IFDs.

KEY MESSAGE 2...Showers are likely Sunday, but areal average rainfall amounts look minimal. Fire WX concerns return next Monday in the wake of the cold front, especially if rainfall amounts are minimal. Model guidance for Sunday continues to show a much stronger cold front crossing the region with a low pressure system tracking into Ontario/Quebec. Ahead of the cold front moisture return looks to be quite minimal for a widespread soaking rainfall. NBM PoPs are higher than numerical guidance, s have split the difference, going with 65-75% for most of the area, with highest PoPs in the N/NW (80-85%). The front appears to be mostly ana-frontal in nature (rain falling primarily behind the frontal passage). With the front passing the area during the early part of the day for the NW 1/2 of the CWA, temps in the late morning and early afternoon will likely drop into the 50s for much of the region. This could easily yield 24 hour temp changes on the order of 30 degrees F. The 12z/17 ensemble probs for 0.1"+ QPF is are remaining steady between 50-70%, but Probs for .25"+ remain quite low.

Behind the front Sunday night/Monday, a much cooler and drier airmass will move into place. Lows mostly in the 40s Sun night, could even see stray upper 30s in the piedmont but no frost is expected. Min RH values Monday look to be 20-25%, possibly lower in the piedmont. In addition, it will be quite breezy behind the front with wind gusts between 20-25mph. It may not be windy enough for a Red Flag event, but at least an IFD for Fire WX is likely for Monday.

KEY MESSAGE 3...There is the potential for patchy frost and even localized freezing temperatures for inland areas Monday night into Tuesday morning. Then temperatures begin to increase through the middle of the week.

The latest suite of models and ensembles remain in good agreement with strong high pressure (>1030mb) moving in from the Great Lakes Monday evening, eventually settling across the local area by Tuesday morning. There are some minor timing discrepancies, the GFS being faster than the ECMWF/GEM which would have implications on how efficient the winds will decouple across eastern portions of the FA (the GFS would suggest it decouples for all but the immediate coast while the ECMWF/GEM would keep more mixing going along and E of I-95 most of the night). With very low dew pts initially, and model spread in the exact position of the sfc high, frost potential is uncertain though patchy frost cannot be ruled out especially across the far NW. Current forecast lows are in the low-mid 30s well inland, with most of the CWA in the mid 30s to around 40F. A localized light freeze is possible for rural areas along and W of I-95, but a hard freeze is very unlikely. By Tuesday, the high will gradually slide off the coast, allowing temperatures to rebound (though still remaining below average, especially on the coast and the eastern shore). Much warmer Wed- Fri as an upper level ridge approaches from the west with temperatures once again trending back above normal (at least for inland areas).

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

As of 810 PM EDT Friday...

VFR conditions will prevail at most terminals through the TAF period, with the exception being SBY, where fog development is possible overnight. Otherwise, mostly clear tonight becoming partly cloudy tomorrow as upper clouds move into the region ahead of a front. Winds will be light and variable overnight, becoming east to southeast and increasing to 6-10 kts tomorrow afternoon.

Outlook: VFR and dry conditions are expected to prevail Saturday night with breezy SW winds. Showers are likely Sunday with the next cold front, along with breezy SSW winds ahead of the front early, shifting to the N-NW behind the front. The timing of the wind shift is a little faster- now expected in the morning for most areas (lagging until the late morning or early aftn across far southern VA and NE NC). VFR Sun night-Tuesday with breezy NW winds Monday, light winds thereafter.

MARINE

As of 230 PM EDT Friday...

Key Messages:

- Sub-SCA conditions are expected to prevail through Saturday.

- Solid SCA conditions expected Sunday ahead of and behind a strong cold front.

Afternoon analysis shows weak (1010mb) low pressure off the Mid Atlantic coast with a weak front extending to the southwest. Winds ahead of the boundary are S or SE 5-10 kt with areas behind the front mostly NW 5-10 kt. Waves are around 1 foot in the bay with seas 2-3 ft. Latest guidance continues to show a weak backdoor cold front sliding down the coast early Saturday morning, allowing the wind to become E 5-10kt. Some marine fog is possible, mainly for the northern coastal waters Saturday morning into the afternoon. The boundary washes out by Saturday aftn with the wind becoming SE 10- 15kt and then S 10-15kt by the evening. Seas remain 2-3ft through Saturday, with 1ft to occasionally 2ft waves in the Ches. Bay.

A strong cold front approaches from the NW late Saturday night and crosses the coast Sunday morning. SW winds are expected to increase to 15-25kt in advance of the front and then shift to NW behind the front. 12z/17 NAM/GFS continue to depict sharp pressure rises of 5- 7mb/3hr in the immediate wake of the cold front with 950mb wind speeds of 35-40kt. Local wind probs for 34 kt gusts have decreased somewhat with portions of the bay and coastal waters briefly rising to ~50% in the immediate wake of the cold front. While it still appears the potential for longer-lived (3-6 hr) Gale conditions is low, will continue to monitor this period in subsequent forecast cycles. Seas build to 4-5ft in the coastal waters and 5-6ft in the offshore waters, with 3-4ft waves in the Ches. Bay. The wind generally remains NW Sunday night into Monday, with a weak secondary cold front possible Monday. High pressure passes across the region Tuesday and settles offshore by the middle of next week with sub-SCA conditions expected. 3-4ft seas early next week should subside to 2- 3ft by the middle of the week, with 2-3ft waves in the Ches. Bay subsiding to 1-2ft.

CLIMATE

While RIC may approach 90F on Saturday, no additional records are expected with the record being 95. It will be much cooler closer to the coast, and nowhere near records.

AKQ WATCHES/WARNINGS/ADVISORIES

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