Marine Weather and Tide Forecast for King William, VA

KEY MESSAGES
1) Slightly Cooler temperatures and minimal fire weather concerns expected today.

2) Fire weather concerns once again increase Saturday with unseasonably warm temperatures. A potentially more significant Fire WX event is possible next Monday in the wake of the cold front but will be dependent on rainfall Sunday.

3) Potential for patchy frost increases Monday night into Tuesday.
Then temperatures begin to increase through the middle of the week.

DISCUSSION
As of 320 AM EDT Friday...

KEY MESSAGE 1...Slightly cooler but warm temperatures and minimal fire weather concerns expected today.

Morning weather analysis shows a weak upper trough moving over the Mid-Atlantic region. While at the surface high pressure continues to remain steady off the SE Coast. The line of showers to the west have begun to fizzle once they moved off the mountains. Decided to lower pops to slight chance due to the showers fizzling out and high-res guidance continuing to limit shower activity. Otherwise, temperatures this morning continue to remain quite mild for this time of year with temps in the upper 60s to low 70s.

Through the course of the day a shortwave will move through the area causing an increase in cloud cover. Due to increase in high level clouds, temperatures will remain slightly cooler than previous days with highs reaching in the mid to upper 80s across VA & NC and low 80s across the Eastern Shore. In addition, Fire Weather concerns remain minimal today due to the lighter winds but min RH values will be between 25-30% inland.

KEY MESSAGE 2... Fire weather concerns once again increase Saturday with unseasonably warm temperatures. A potentially more significant Fire WX event is possible next Monday in the wake of the cold front but will be dependent on rainfall Sunday.

Saturday continues to remain on track with warm/hot and dry weather conditions expected. Temperatures are progged to be in the upper 80s to low 90s inland and mid to low 80s along the SE coast and middle to upper 70s along the coast. With warmer temperatures expected this could allow for additional mixing at the surface causing winds to be higher (15-20mph gusts). These gusts mixed with RH values between 25-30% could lead to an Increase in Fire Danger especially along and west of the I-95 corridor. While further east temperatures are expected to be cooler and RH higher due to the onshore flow.

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. PoPs have increased just slightly and are now between 65-85% for most of the area with the lowest towards the SW. Showers are expected through the day, with perhaps a low end chance of thunder across the SE. Showers look to fall primarily behind the frontal passage. With the front passing the area during the day, temps in the afternoon will likely drop into the 60s (or perhaps 50s all depending on if/where it rains).
This could easily yield 24 hour temp changes on the order of 30 degrees F. The 00z/17 ensemble probs for .1"+ QPF is remaining steady between 60-70% , and are highest across across the NE and lowest across the SW. Probailities of any greater QPF values remain quite minimal (less than 10%.

Behind the front Monday, a much cooler and drier airmass will move into place. The NBM which often has a bias to high dew points, depicts min RH values between 15-25%. In addition, it will be quite breezy behind the front with wind gusts between 20-25mph. If rainfall remains quite minimal with the frontal passage Sunday, the combination with breezy conditions and Low RH could give way to Red Flag Warning criteria especially W of the I-95 corridor.

KEY MESSAGE 3...Potential for patchy frost increases Monday night into Tuesday. Then temperatures begin to increase through the middle of the week.

High pressure at the surface is progged to move over the area late Monday into Tuesday. As the high moves overhead it will allow for winds to decouple and skies to remain clear. This will allow for strong radiational cooling to occur and temperatures could drop into the low to middle 30s inland and upper 30s to low 40s along the coast. A freeze is not expected at this time due to dew points remaining quite low. However, patchy frost cannot be ruled out especially across the far NW. By Tuesday, the high will move back offshore across the SE and temperatures will begin to warm back up.
Then through the rest of the week a ridge build back into place and temperatures will once again return back into the 80s with dry weather prevailing.

AVIATION /07Z FRIDAY THROUGH TUESDAY/
As of 1257 AM EDT Friday...

VFR is expected to prevail through the 17/06z TAF period.
Mostly clear to partly cloudy skies early this morning. These clouds are from a passing sfc trough and mid- level shortwave, which could also spark a few isolated showers early Friday morning. The best chances for showers (but still only ~30%) are at RIC between 10-14z. No flight restrictions are expected but continues to include a PROB30 group for situational awareness.
Skies gradually clear behind the feature Friday, with perhaps some CU developing near the coast. SW winds become W ~5 kt late tonight and then shift to the NW Friday. A localized onshore wind may develop later in the afternoon for ORF and ECG as a sea breeze attempts to push inland.

Outlook: VFR and dry conditions are expected to prevail through Saturday night. Mainly S-SW winds also prevail throughout the forecast period, as high pressure settles over the western Atlantic. Showers are likely Sunday with the next cold front, along with breezy SSW winds ahead of the front, and N-NW winds behind the front late Sun into Monday.

MARINE
As of 320 AM 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.

A weak trough is approaching from the NW early this morning. The wind is SW 10-15kt ahead of the trough, and occasionally to 15-20kt over the Ches. Bay and coastal/offshore waters. Seas in the coastal waters range from 2-3ft S to 3-4ft N, with 3-5ft seas in the offshore waters. Waves in the Ches. Bay are ~2ft. The trough will slide across the coast this morning with the wind becoming WNW 5- 10kt. The pressure gradient becomes rather nebulous later this aftn into tonight with the wind becoming light and variable. A weak backdoor cold front slides down the coast early Saturday morning allowing the wind to become E 5-10kt. This boundary washes out by Saturday aftn with the wind becoming SE 10-15kt and then S 10-15kt by the evening. Seas subside to 2-3ft today and 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. A SW wind is expected to increase to 15-25kt in advance of the front and then shift to NW behind the front. 00z/17 NAM/GFS each 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 continue to shows a 50-70% chc of 34kt gusts.
However, it is over a short time period. SCA conditions are expected in advance of and behind the cold front, with brief gale conditions likely immediately behind the front, and the main uncertainly with gales being duration (i.e. 3-6 hr Gale Warning vs. 1-2hr post- frontal SMW). 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
Another record high was set at Norfolk today (92). Temps fell a few degrees shy of records elsewhere.

Record High Temps for 4/16 - 4/18

Record Record Record High/Yr High/Yr High/Yr Location 4/16 4/17 4/18 -------- ----- ------ ------ Richmond 93 (1976) 96 (1976) 95 (1976)
Norfolk 91 (1976) 93 (2002) 95 (1896)
Salisbury 89 (1976) 92 (2002) 90 (1976)
Eliz. City 90 (1941) 92 (1976) 91 (1941)

Record High Min Temps for 4/16 - 4/18

Record Record Record High High High Min T/Yr Min T/Yr Min T/Yr Location 4/16 4/17 4/18 -------- ---- ----- ------ Richmond 64 (1912) 65 (1912) 64 (2002)
Norfolk 66 (2017) 68 (2002) 68 (2002)
Salisbury 63 (2017) 64 (2002) 65 (1918)
Eliz. City 68 (1994) 68 (1945) 65 (2002)

AKQ WATCHES/WARNINGS/ADVISORIES
MD...None.
NC...None.
VA...None.
MARINE...None.