textproduct: Wakefield

WHAT HAS CHANGED

- Updated Discussion, 00z aviation discussion, and Key Messages.

- Frost and Freeze headlines have been added for much of the area for late tonight.

KEY MESSAGES

1) Mostly sunny and cooler this afternoon. Another cold night tonight, with additional Frost/Freeze headline potential for late tonight/early Thu AM.

2) Remaining mainly dry through the middle of next week. Temperatures Friday-Sunday will be mostly above average but still seasonable, followed by a well above normal period early next week.

DISCUSSION

As of 145 PM EDT Wednesday...

KEY MESSAGE 1...Mostly sunny and cooler this afternoon. Another cold night tonight, with additional Frost/Freeze headline potential for late tonight/early Thu AM.

Strong high pressure (~1037mb) is centered along the SE New England and northern mid-Atlantic coast this afternoon. Aloft, W-NW flow persists, in between a broad northern stream trough traversing the Dakotas and building upper ridging over the Gulf coast. Mainly sunny, but very dry and chilly, especially along the coast. Highs along the coast mainly in the upper 40s to low 50s as of this writing, with low to mid 50s farther inland. RH values remain quite dry well inland, while the cool onshore flow is allowing for somewhat higher values closer to the coast.

Previously referenced sfc high builds east tonight, becoming centered along the coast of New England and ridging down the mid- Atlantic coast into the coastal Carolinas. This setup is much more favorable for radiational cooling, given slackening pressure gradient/less mixing over inland areas. Additionally, the onshore flow also allows for some limited moisture return in lower levels, resulting in some slightly higher dew pts, especially along the coast. Farther inland, the combination of slightly higher Td (lower T/Td depressions) and high RH, along with the diminishing winds make frost formation significantly more likely. Forecast lows remain in the low- mid 30s tonight. A persistence- based forecast meshes well with statistical guidance, leading to increased confidence for more widespread frost formation just inland tonight, with temperatures just below freezing well inland out toward the US-15 corridor north of Farmville. In collaboration with surrounding offices, have issued a relatively broad swath of Frost Advisories just inland of the SE coastal plain, with a Freeze Warning for our far NW in Louisa/Fluvanna counties. CAMs continue to show potential for some building stratocu pushing inland late tonight, with the best chances across SE coastal terminals. The mid-cloud deck and onshore flow should help to keep temps near to above freezing along the coast.

KEY MESSAGE 2...Remaining mainly dry through the middle of next week. Temperatures Friday-Sunday will be mostly above average but still seasonable, followed by a well above normal period early next week.

After a cold start, temperatures rebound closer to average Thursday, as the sfc high gradually weakens and shifts farther off the northeast coast. The previously referenced northern plains upper level trough slides across Ontario into New England late Thu into Sat, and will eventually push a cold front toward our area late Fri into Sat. Given the dry antecedent airmass, the cold front likely weakens considerably before reaching our area, bringing little more than some increased cloud cover for Saturday.

Better return flow should return high temperature back into the 70s for most areas west of the bay Friday (65 to 70 eastern shore). However, temperatures do look to cool slightly for Sunday, especially on the ern shore and near the coast, as the low level flow backs to the E-NE. Otherwise, the main weather message for the first half of next week will be increasingly warm and remaining dry. Highs look to warm well into the 80s Mon/Tue, possibly to around 90F Tue- Wed. This will exacerbate the already dry conditions, that are very likely worsen in the medium range. Rain chances are basically zero through the first half of next week. 12Z/08 model ensembles continue to show < 50% chc for 0.50" of total rainfall through the end of next week, as the SE upper ridge continues to keep any significant rain chances well W/NW of the region.

AVIATION /00Z THURSDAY THROUGH MONDAY/

As of 740 PM EDT Wednesday...

Mainly VFR conditions across area terminals this evening but a batch of MVFR CIGs is noted across portions of NE NC, including ECG. Guidance is quite variable with respect to how widespread these MVFR CIGs will be this evening and overnight. Opted to take a middle of the road approach and include prevailing MVFR at ECG this evening and later at ORF and SBY. PHF is problematic but went with low end VFR. Winds mainly ENE area-wide tonight, 5-10 kt near the coast and light inland. The pressure gradient is and will remain steepest at ECG so have winds staying aoa 10 kt overnight and 10-15 kt by mid morning Thursday.

Outlook: Dry with VFR conditions Friday and Saturday. A weakening cold front drops across the region Saturday afternoon and night that will bring some clouds, but rain chances look very limited through early next week.

MARINE

As of 250 PM EDT Wednesday...

Key Messages:

- Winds will continue to diminish through this evening and into tonight as the gradient relaxes.

- Elevated seas will maintain Small Craft Advisory conditions on the ocean through much of the week and into the weekend.

This afternoon, strong (~1039 mb) high pressure is centered north of the area and extending south into the local area. Low pressure that was centered east of the Florida Peninsula this morning has moved well offshore. The gradient has relaxed from earlier and winds have started to diminish. NE winds over the northern coastal waters and Chesapeake Bay range from 10 to 15 knots with gusts to ~20 knots. Winds over the southern bay and southern half of the coastal waters remain elevated with sustained winds averaging 15 to 20 knots and gusts of 25 to 30 knots. Winds will continue to relax from north to south as we head through this evening and into tonight. The onshore wind has allowed for seas to increase to 4 to 6 feet over the northern half of the coastal waters and 6 to 8 feet (locally 9 feet) over the southern waters. SCAs remain in effect for the southern half of the Chesapeake Bay, all coastal waters, and the Currituck Sound.

While winds will relax tonight, seas will remain elevated due to the long fetch of NE winds. There is a good chance that seas across the southern waters continue to over perform, as that is common in this NE wind regime. The prolonged period of ENE winds will keep seas elevated in the coastal waters and mouth of the Chesapeake Bay through the day Friday, so the SCA has been extended through then, and may need to be extended into the early weekend even as winds turn offshore Friday and Saturday. Otherwise, the next potential for winds approaching SCA are not until late in the weekend or early next week.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...Frost Advisory from 2 AM to 9 AM EDT Thursday for MDZ021>024. NC...Frost Advisory from 2 AM to 9 AM EDT Thursday for NCZ012-013. High Surf Advisory until 10 PM EDT this evening for NCZ102. VA...Frost Advisory from 2 AM to 9 AM EDT Thursday for VAZ060>062- 064>069-075-076-079>083-087>089-092-511>522. Freeze Warning from 2 AM to 9 AM EDT Thursday for VAZ048-509- 510. MARINE...Small Craft Advisory until 10 PM EDT this evening for ANZ632- 633. Small Craft Advisory until 7 PM EDT Friday for ANZ634-650-652- 654-656-658.