textproduct: Wakefield

WHAT HAS CHANGED

Updated discussion. A Slight Risk for severe weather has been introduced for areas north of I-64 and a Marginal risk remains in place for areas north of route 58 on Wednesday. Confidence in storm formation Wednesday afternoon/evening is still low, but has increased slightly from this morning. A strong cold front is still expected to cross the area Wed night into Thurs AM, bringing additional showers and a change in airmass. A Gale Watch has been issued for Thursday for the mouth of the Chesapeake Bay, and the Ocean between Cape Charles and Currituck Beach Light.

KEY MESSAGES

1) Record or near record warmth is expected again tomorrow. There is a low chance for strong to severe storms Wednesday afternoon and evening, mainly north of I-64.

2) A stronger cold front crosses the area Thursday morning-midday, bringing the next chance for precipitation, along with a low-end potential for some stronger storms during the first part of Thursday. Cooler temperatures and dry weather returns to end the week.

DISCUSSION

As of 329 PM EDT Tuesday...

KEY MESSAGE 1...Record or near record warmth is expected again tomorrow. There is a low chance for strong to severe storms Wednesday afternoon and evening, mainly north of I-64.

Afternoon WX analysis shows primarily SW zonal flow aloft. While at the surface, high pressure remains off the SE coast helping to advect in warmer air across the area. Temperatures as of 2PM Tuesday have warmed up into the upper 70s to low 80s across the area. In addition to the warm temperatures, dew points have been able to mix out through the day leading to RH values between 25 to 25% inland and 35-45% along the coast. Luckily due to the weak pressure gradient over the area allowing for light winds there are minimal fire WX concerns for this afternoon. For tonight, temperatures will continue to remain mild for this time of year with lows falling down into the middle to upper 50s and low 60s.

Wednesday will be another warm day across the area as mostly sunny and mostly dry conditions prevail. Highs Wednesday are expected to approach the low to middle 80s inland. There is moderate to high confidence that some of our climate sites may break their record high temperatures. See the climate section below for more information. Overnight lows will remain mild Wed night, though an upper level trough and cold front will keep upper level heights from rising Wed. While the best height falls and stronger upper level dynamics from the approaching trough remain to the west and north Wed, the warm temperatures and lower to middle 60 dews will allow for 500-1250 J/kg of MLCAPE to develop by the mid to late afternoon. With the strong enough upper level wind deep-layer shear (mainly speed shear) will also be plentiful. Recent CAMS have now hinted on some showers/storm development primarily across the north. This is most likely due to the CAP potentially being slightly weaker to the north. While across the south model soundings continue to show a stronger CAP remaining in place. Due to the uncertainty in the CAP only a chance POP (25-30%) remains across the north with a slight chance of pops extending south. Nonetheless, given the environment in place, a severe storm or two cannot be ruled out if convection develops. The main threats would be damaging winds and severe hail. However, a tornado cannot be ruled out due to recent soundings showing 0-1km SRH around 100-150 m^2/s^2 of SRH. While confidence in storm initiation is low, the setup Wed afternoon/evening will continued to be monitored. The best chc of a stronger storm would be north of I-64. SPC has expanded a slight (Level 2/5) Risk to include all areas north of the I-64 border on Wednesday to account for this threat. While down south a Marginal (Level 1/5) Risk is extended from south of I-64 down to Rt-58.

KEY MESSAGE 2... A stronger cold front crosses the area Thursday morning-midday, bringing the next chance for precipitation, along with a low-end potential for some stronger storms during the first part of Thursday. Cooler temperatures and dry weather returns to end the week.

A strong upper level trough is expected to lift across the Gulf coast Wed before moving into the Carolinas Thursday. Meanwhile to the north, a dynamic northern stream trough is expected to lift across the upper Midwest into northeast and SE Canada. A deepening low pressure is progged to track from the Great Lakes vicinity to Quebec Wed-Thurs AM. The potential sub-990mb northern low is expected to drag a strong cold front through the local area Thursday AM to midday. The precipitation associated with the front is progged to fall behind the front with the best precip chances from late morning-early evening) as that southern stream system tracks just to our south. Temps will not drop much below 70F prior to the FROPA Thu AM as winds veer from the S to SW.

Temperatures will likely warm a couple degrees across SE VA/NE NC Thurs AM before the cold front moves through. With dew points remaining in the upper 50s to low 60s and modest temps, some destabilization is possible ahead of the frontal boundary (mainly in areas that see a couple hours of daytime heating). Combined with the strong low-level wind fields and the potential for a narrow convective line of low-topped gusty showers, cannot rule out a few strong to potentially severe (50 kt) wind gusts on Thursday with that line. However, confidence in any severe weather is low at this time. Behind the front temps are expected to drop from around 70F to the 40s-50s very quickly. with a few hours worth of 30-35 mph gusts likely across much of the area as winds become NW. With pressure rises behind the front Thurs temperatures will fall through the day and through the evening as as seasonably strong CAA ensues. Thus, the high temperatures shown in the forecast are likely to be achieved early in the day, with those falling temps as the day proceeds. Precip should end well before any changeover to snow could potentially occur.

Looking through the extended, seasonably cooler and dry weather returns Friday, with highs dropping back into the 50s despite plentiful sunshine. Milder conditions with temps approaching 70 F are forecasted by the weekend as transient high pressure slides over, also supporting continued mainly dry wx. Another low pressure system and cold front brings a good chance of showers (with perhaps an isolated tstm) to the area on Monday.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/

As of 735 PM EDT Tuesday...

VFR conditions will prevail at all terminals through the TAF period. There is a chance for some ground fog mainly at ECG, but there is low confidence at this time for development, so have just left brief MVFR VIS from 10-12z. Otherwise, S-SW winds will start to pick up by midday into the early afternoon, with gusts of 20-25 kts expected through the evening. There is a slight chance for thunderstorm development (mainly at RIC and SBY) before 00z tomorrow evening, but uncertainty is high regarding timing and if they will actually develop, so have left out any mention of thunder for now.

Outlook: A strong cold front approaches Wednesday night into Thursday, which is expected to bring showers and a few tstms, along with periodic flight restrictions. VFR conditions return Friday into Saturday.

MARINE

As of 240 PM EDT Tuesday...

- Generally benign marine conditions are expected to persist through Wednesday morning.

- A strong cold front approaches late Wednesday and crosses the waters early Thursday. SCA conditions are likely both ahead of and behind the frontal passage, with chance for Gales post- frontal on Thu at the Mouth of the Bay and southern Ocean. A weak sfc trough is located over the region this aftn, with winds generally southerly at 10 kt or less, waves 1-2 ft and seas ~2 ft. Strong low pressure continues to deepen across the central CONUS, and this feature will lift ENE towards the Great Lakes into Wednesday with the pressure gradient gradually tightening by the late Wednesday afternoon into the evening. SCA conditions are likely Wednesday night in strengthening SSW flow. Cool near- shore waters will limit mixing but the synoptic gradient will be quite strong. The front is progged to cross the waters around sunrise Thursday across the N and a few hrs later in the south, shifting the winds to the NW and then NNW behind the boundary. With rapid pressure rises (model output showing 6 hr rises forecast to be 9-12 mb), a period of stronger winds will likely follow just behind the front. Gusts will likely exceed 30-35 kt during this period, but only for 1-2 hrs or less at most locations. Have decided to hoist a Gale Watch for the Ocean S of Cape Charles, and the mouth of the Bay where the chance for seeing at least a 3hr + period with gusts of 34kt or greater is highest. The gradient begins to relax Thursday afternoon and especially during the evening and overnight hours.

Seas will build to 4-6 ft N and 3-5 ft S in the pre- frontal SW flow but should fall off quickly Thursday afternoon as flow turns offshore, the exception being in the Gale Watch area of the Ocean where seas may briefly build as high as 6-7 ft. Waves in the Chesapeake Bay will increase to 2- 4 ft ahead of the front and reach to 3-5 ft through much of Thursday during the stronger NNW winds. Another system moves by well to the north on Friday with potential for another period of SCA conditions.

CLIMATE

As of 230 PM EDT Tuesday...

Record highs were set at ORF (83F), RIC (85F), and SBY (83F), while the record high was tied at ECG (82F) today. Both record highs and record high mins are likely for Wed 3/11.

- Record High Temps for 3/10 - 3/11

Record Record High/Year High/Year Location 3/10 3/11 -------- ---- ----- Richmond 81 (2006) 82 (1990) Norfolk 81 (2016) 82 (1990) Salisbury 77 (2016) 76 (2000) Eliz. City 82 (2016) 81 (2016)

- Record High Min Temps for Wed 3/11

Location Rec High Min -------- ------------ - Richmond 56 (1955) - Norfolk 62 (1925) - Salisbury 51 (1955) - Eliz. City 58 (1967)

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Gale Watch from Thursday morning through Thursday afternoon for ANZ634. Gale Watch from Thursday morning through Thursday afternoon for ANZ656-658.