textproduct: Wakefield

WHAT HAS CHANGED

Rain chances for some light showers have increased along the coast for this afternoon. Temperatures have also been trended lower for next week.

KEY MESSAGES

1) Increasing clouds but remaining mild today. A few light rain showers are possible this afternoon into early this evening along the coast.

2) A strong cold front crosses the area late tonight into Thursday. Low pressure will develop along the front, and track north of the region on Thursday. Scattered light rain showers are possible tonight, possibly ending as a brief period of non-accumulating/trace light snow. No snow accumulations or impacts are expected.

3) Turning colder Thursday through late week. Below normal temperatures are expected from Thursday night into early next week. Mainly dry throughout the period, though there is a low- end chance for some light precipitation both Saturday and Sunday.

DISCUSSION

As of 555 AM EST Wednesday...

KEY MESSAGE 1...Increasing clouds but remaining mild today. Some scattered light rain showers are possible this afternoon into early this evening along the coast.

Weakening surface high pressure continues to slide farther out into the Atlantic early this morning, as Low pressure slides across Ontario into Quebec. To the west, a trough continues to dig south across the Ohio and TN River Valleys. Out ahead of this system, a weak shortwave currently across the Gulf Coast will lift along the Coastal Carolinas toward the Delmarva coast later this morning into this evening. Despite increasing clouds in association with this feature and the northern stream system, temperatures stay mild today on deep-layered SSW flow. Highs today will be the warmest for the next week or so, ranging from the mid to upper 50s (lower 50s for the Eastern Shore).

CAMs have come in a bit stronger with overrunning light rain or sprinkles this afternoon along the coast, so have increased rain chances along the coast this afternoon into early this evening to 40-50%. Given antecedent dry airmass, rainfall totals will be quite light, on the order of a hundredth or two at most.

KEY MESSAGE 2...A strong cold front crosses the area late tonight into Thursday. Low pressure will develop along the front, and track north of the region on Thursday. Scattered light rain showers are possible tonight, possibly ending as a brief period of non-accumulating/trace light snow. No snow accumulations or impacts are expected.

A potent northern stream shortwave will dig south into the mid- south and Gulf coast region tonight before ejecting NE into the northern mid- Atlantic tonight through Thursday. The local area will be sandwiched between the two streams in the subsident/ moisture deprived region. Most importantly, the associated strong surface cold front sweeps into the region late tonight into Thursday morning. High res CAMs are again keying on a narrow band of overrunning showers along or just behind the front. QPF totals remain very low with this second round of precipitation as well, as most moisture gets hung up on the Appalachian mountains or pulled towards the exiting southern stream system. There is a chance for precipitation to change over to some very light snow showers or flurries as precipitation ends, but due to the warm ground temperatures and weak precipitation rates, no accumulation or impacts are expected with the snow.

KEY MESSAGE 3...Turning colder, with below normal temperatures expected from Thursday night into early next week. Mainly dry throughout the period, though there is a low-end chance for some light precipitation both Saturday and Sunday.

Temperatures quickly drop behind the strong Arctic cold front Thursday morning. Strong CAA will bring below average temperatures and breezy/windy conditions. Highs Thursday likely get achieved early in the day along the coast (or in the pre-dawn hours inland). Low temperatures Thursday night fall into the mid teens inland to around 20 along the coast. Despite diminishing winds, this results in near single digit wind chills inland. Will need to monitor this for any potential Cold Weather Advisories. Highs Friday will be in the 30s to lower 40s, before moderating slightly Saturday back toward climo normal.

Another potent upper trough dives SE out of the Canadian Prairies this weekend, driving another pair of Arctic cold fronts across the local area Sat/Sun. Waves of shortwave energy embedded in the digging upper trough also cross the area over the weekend, bringing additional opportunities for mainly light wintry precipitation Sat/Sun afternoons. For planning purposes, it should also be noted that the 00z/14 models, particularly the deterministic ECMWF and a good number of both EPS/GEFS members, have been a bit more aggressive in digging that trough a bit farther south and tapping into some Gulf moisture. The evolution of the shortwave will be the key to this forecast. If coastal low pressure can develop offshore of the southeast coast, there may be enough time/moisture to produce some additional wintry precipitation on Sunday. This remains a low-confidence scenario at this time, hence the 20-30% PoPs. However, it certainly does bear watching over the next several model cycles. In any scenario, after a very brief (1 day!) moderating trend on Saturday, another round of cold temperatures returns to the region for the first half of next week. Highs mainly in the 30s and lows in the teens to low 20s both Sunday through the middle of next week.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

As of 555 AM EST Wednesday...

VFR conditions prevail across all terminals through the 12z/14 TAF period. Mid to high level clouds continue to increase over the northern half of the area from RIC to SBY. W/SW winds around 10 kt will continue through this evening. Continue to account for some some low- level wind shear for a few more hours early this morning at RIC and SBY, in association with a weak LLJ lifting across the northern half of the area into the northeast CONUS. Clouds will gradually thicken and lower across the entire area this morning, with the cloud shield from the next approaching low pressure system to the north and associated cold front. Despite the antecedent dry conditions, some isolated to widely scattered showers will be possible across the SE terminals from ORF to ECG this afternoon into this evening in association with a dampening southern stream shortwave lifting along the SE coast into the SE third of the area. Have accounted for a PROB30 for some SHRAs at ECG/ORF/PHF for the late afternoon into this evening.

Outlook: The cold front will cross the local area late this evening into early Thursday, with another round of light rain showers possible. Precipitation potentially ending as some wet snowflakes before ending early Thursday morning. A brief period of sub-VFR conditions will be possible early Thu morning, as a secondary front crosses the region, ushering in a much colder airmass for the late week period into the upcoming weekend.

MARINE

As of 250 AM EST Wednesday...

Key Messages:

- Low-end Small Craft Advisory conditions are expected today (especially this morning) with gusty S-SW winds.

- Strong northwesterly winds are expected tonight through Friday morning. High-end SCA conditions are expected with Gale conditions possible, particularly Thursday night.

- Tidal anomalies remain low for the foreseeable future and low water conditions are possible in the lower Chesapeake Bay and James River by Friday.

Strong low pressure is moving through southern Canada this morning, with a developing cold front extending SW through the Great Lakes Midwest. To our east, high pressure continues to retreat further offshore. A compressed pressure gradient remains over the local waters this morning ahead of these features, with a SW low-level jet helping to supplement higher winds at the surface. Marginal Small Craft Advisory conditions are ongoing in the Chesapeake Bay and central/northern coastal waters and SCAs are in effect through at least this morning. S-SW winds will likely decrease some later this morning and afternoon, but should remain 15-20 kt on the ocean.

The bigger story will be the strong cold front that is expected to push through the region late tonight and early Thursday morning. An abrupt wind shift to the NW will accompany this frontal passage with winds quickly increasing to 20-25 kt with frequent gusts to 30 kt, continuing through most of Thursday and Thursday night. Prevailing winds may be a bit lower on the upper rivers and Currituck Sound, but are expected to reach SCA criteria regardless. Additionally, there are two periods where low-end Gale conditions are possible: 1) early Thursday morning along the immediate cold front and 2) Thursday night-Friday morning as strong CAA and pressure rises overspread the waters. The first of these will likely be quite brief (<2 hrs) and can be handled with Special Marine Warnings, if necessary. Model guidance has trended upward during this second timeframe (overnight Thursday) with increasing confidence in 35-40 kt wind gusts on central-northern coastal waters. Have therefore issued a Gale Watch from 00z-12z Fri (7 PM Thu-7 AM Fri). Could need to expand this into the Chesapeake Bay and southern coastal waters in future updates, but confidence and probabilities are lower here. Regardless, this will be a very cold airmass and these situations tend to overperform in the wind department. Regarding headlines: will let the ongoing SCA drop off in the bay at 10 AM this morning before issuing SCAs for Thursday-Friday morning. For the rivers, Currituck Sound, and ocean S of Cape Charles, have gone ahead and issued SCAs from tonight into early Friday morning. For the northern coastal waters, the SCA is in effect through 00z Fri, transitioning to the aforementioned Gale Watch through 12z Fri. Winds ramp down considerably later Friday morning but lingering SCAs are possible through noon or so. SW winds increase again Friday night with another round of SCAs possible. Lower confidence by Sunday as low pressure may develop offshore, but additional SCAs are again possible.

Seas are 4-5 ft N and 2-4 ft S this morning, with waves around 2 ft elsewhere in the bay/rivers/sound. Seas may subside a bit this afternoon as winds decrease some, but expecting a ramp up again tonight to 3-5 ft as winds increase behind the cold front. Seas increase further Thursday night to 4-6 ft, with 3-5 ft waves possible in the Chesapeake Bay as well.

Lastly...tidal anomalies remain low for the foreseeable future. Tides generally trend lower by Friday and especially Saturday with low water (and Low Water Advisories) possible in the lower Chesapeake Bay, James River, York River, and the Atlantic coast.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 10 AM EST this morning for ANZ630>632-634. Small Craft Advisory from 4 AM Thursday to 7 AM EST Friday for ANZ633. Small Craft Advisory from 1 AM Thursday to 4 AM EST Friday for ANZ635>637. Small Craft Advisory from 1 AM Thursday to 7 AM EST Friday for ANZ638-656-658. Small Craft Advisory until 7 PM EST Thursday for ANZ650-652- 654. Gale Watch from Thursday evening through Friday morning for ANZ650-652-654.