textproduct: Wakefield

WHAT HAS CHANGED

Updated discussion. It is looking increasingly likely that we will see the rain change to snow across central/eastern VA and the MD Eastern Shore for an hour or two during the afternoon. While no impacts are expected, a dusting on grassy surfaces is possible.

KEY MESSAGES

1) A strong cold front crosses the area between 6 AM and noon today. Temperatures will fall into the mid 30s to lower 40s by the afternoon. There is a very good chance of rain, along with a low-end potential for some stronger storms across NE NC between 9 AM and noon today. The rain may change to snow for an hour or two this afternoon across central/eastern VA and the MD Eastern Shore. A dusting of snow is possible on grassy surfaces.

2) Cooler temperatures and dry weather return to end the week. Another storm system brings a chance for showers and thunderstorms to the area on Monday.

DISCUSSION

As of 220 AM EDT Thursday...

KEY MESSAGE 1...A strong cold front crosses the area between 6 AM and noon today. Temperatures will fall into the mid 30s to lower 40s by the afternoon. There is a very good chance of rain, along with a low-end potential for some stronger storms across NE NC between 9 AM and noon today. The rain may change to snow for an hour or two this afternoon across central/eastern VA and the MD Eastern Shore. A dusting of snow is possible on grassy surfaces.

A southern stream low pressure system currently over the Deep South tracks ENE through the Carolinas today, before moving offshore by this evening. Meanwhile, a strong cold front just to our north will quickly cross the area from NNW-SSE between 6 AM and noon. It is warm with lower-mid 70s at this hour/breezy SSW winds. Temperatures will likely warm a couple degrees across SE VA/NE NC later this morning before the cold front moves through. The front should cross central/northern zones by 8-9 AM, allowing temps to fall into the 40s by noon. While the vast majority of the precipitation is progged to fall behind the front, a line of showers will likely accompany the front as it crosses the area. Some pre-frontal destabilization (MLCAPE ~1000 J/kg) is likely across extreme SE VA and especially NE NC. While most areas will see gusts to 30-40 mph as the front moves through, an isolated strong storm producing 45-60 mph wind gusts can't completely be ruled out, though confidence in this is low. The best chc of severe wx is in NE NC near the Albemarle Sound where the FROPA is latest. Temps are expected to drop from around 70F to the 40s very quickly following the FROPA, and will continue to fall into the mid 30s-lower 40s by the afternoon. Some areas will see a very impressive 24 hour temperature change on the order of 50 degrees from Wed afternoon to today! A period of rain is likely behind the front between late morning and early evening, with widespread amounts of 0.25-0.75" likely.

It is looking increasingly likely that we will see the rain change to snow across central/eastern VA and perhaps the eastern shore for an hour or two during the afternoon. While falling snow appears likely, it will be very hard for anything to accumulate unless we see consistent moderate to heavy snow for a couple of hours. This is quite unlikely attm. However, up to 1" is not out of the question if we see solid 1/4SM VSBY heavy snow for a couple of hours. And will also note that the positive snow depth change in several of the models is ~20% of the forecast snow totals using the Kuchera snow ratios given the warm ground/sfc temps not dropping below 33-34F. Will advertise up to 0.1-0.3" of accums to account for the possibility of a dusting on the grass (which appears more likely). Regardless of accumulation, it is very rare to see snow on the exact same day with highs in the 70s (the high in RIC will technically be ~76F).

KEY MESSAGE 2...Cooler temperatures and dry weather return to end the week. Another storm system brings a chance for showers and thunderstorms to the area on Monday.

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 70F are forecasted by the weekend as transient high pressure slides over, also supporting continued mainly dry wx. Strong low pressure (potentially sub-980mb) tracks from the Midwest to Ontario/Quebec on Monday/Monday night. That system will drag a cold front through the area Monday night. Ahead of the front, warm and somewhat humid wx is expected on Mon with highs in the 70s and dew pts potentially in the lower-mid 60s. A band of showers, with a few embedded tstms, will cross the area from Monday-Monday evening. There is a chance for a few stronger storms as well (with damaging winds being the main threat). More specifics to come as we get closer.

AVIATION /08Z THURSDAY THROUGH MONDAY/

As of 500 AM EDT Thursday...

VFR conditions are expected through 12z before deteriorating from NW-SE today. Winds will remain gusty out of the S to SW and LLWS is possible at all sites through 12-14z. Attention then turns to a strong cold front set to cross the terminals between 12-16z. Most of the precipitation will fall behind the front, with widespread rain expected through much of the day. Could see a tstm at ORF/ECG between 13-16z, but confidence in this is low but have maintained PROB30 groups to account for the possibility of thunder. CIGs drop to low-end MVFR at all sites by midday. IFR CIGs are also possible at RIC/PHF/ORF this aftn-early evening. A quick drop in temperatures may bring a brief changeover to snow starting around 18-19z at RIC and SBY and ~20-22z at ORF/PHF. Precip likely remains all rain at ECG. Periods of IFR VSBYs are likely with any heavier RASN or SN. There is a low chc of a couple hours worth of 1/2-1SM VSBY snow at RIC/SBY/PHF. SW winds quickly turn to the NW behind the front with gusts of 25-30 knots possible.

Outlook: VFR conditions return tonight and persist into Saturday.

MARINE

As of 210 AM EDT Thursday...

- Small Craft Advisories are in effect for the Chesapeake Bay, tidal rivers, and northern coastal waters into early evening, and go into effect for the Currituck Sound later this morning.

- Gale Warnings go into effect mid morning for the Ocean from Cape Charles to Currituck Beach Light NC, and for the mouth of the Chesapeake Bay.

Surface analysis shows strong low pressure centered north of NY with a sharp cold front extending to the SW along the Appalachians. The pressure gradient is tightening early this morning with SW winds mainly 15-20 kt with gusts to 25 kt. Some elevated sensors in the Ches Bay and offshore have observed gusts around 30 kt which shows that cool waters are impeding deeper mixing and downward momentum transport of the stronger flow aloft. 00z guidance continues to show the strong cold front crossing the waters from around sunrise in the north and clearing the southern waters by late morning. Winds quickly turn NW/NNW behind the boundary. Impressive pressure rises (9-12mb in 6 hours) will immediately follow the cold front and winds could gust 35-40 kt as the boundary comes through. It still appears that the best chance for prolonged gusts of this magnitude will be focused across the southern third of the area from mid to late morning through mid to late afternoon. This includes the mouth of the bay and Atlantic coastal waters south of Cape Charles Light. Elsewhere, the period of post-frontal 30-40 kt gusts will be shorter and will be handled with short-fuse SMWs as needed (this has been mentioned in the MWW). The gradient begins to relax this evening and especially during the overnight hours. Seas will build to 4-6 ft far N and 3-4 ft S in the pre-frontal SW flow early this morning. Seas will avg 4-5 ft N, and will build to 5-7 ft S (where the strongest winds will occur). Waves in the Chesapeake Bay increase to 2-4 ft ahead of the front and reach to 3-5 ft through much of the day during the stronger NNW winds.

Another system moves by well to the north on Friday with potential for another period of SCA conditions (especially for the northern half of the area), as increasing S to SW winds develop. More tranquil marine conditions are expected Saturday into the first half of Sunday before the next strong system approaches the region late Sunday into Monday.

CLIMATE

As of 220 AM EDT Thursday...

Record highs were set at ORF (88F), RIC (89F), SBY (86F), and ECG (86F) yesterday. Record high mins were also set at RIC (58F), SBY (55F), and Norfolk (62F).

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 7 PM EDT this evening for ANZ630>632-635>638-650-652-654. Small Craft Advisory from 10 AM this morning to 7 PM EDT this evening for ANZ633. Small Craft Advisory until 10 AM EDT this morning for ANZ634. Gale Warning from 10 AM this morning to 4 PM EDT this afternoon for ANZ634. Gale Warning from 10 AM this morning to 7 PM EDT this evening for ANZ656-658.