textproduct: Wakefield

WHAT HAS CHANGED

Updated Aviation Section. No significant changes at this time.

KEY MESSAGES

1) Seasonable temperatures and dry this week.

2) Moisture does not return until late this weekend into early next week.

DISCUSSION

As of 330 AM EDT Monday...

KEY MESSAGE 1...Seasonable temperatures and dry this week.

Low pressure is centered off the coast of southern New England early this morning, with a trailing cold front off the Mid- Atlantic coast. Meanwhile, a narrow ridge of surface high pressure is located over the Piedmont. Widespread stratus covers much of the region early this morning, with some fog possible over the Piedmont toward sunrise. A shortwave trough will track across the Northeast early this morning, which will allow for low pressure to lift to the NE and the cold front to move farther offshore. This will allow drier air to filter in from the N with stratus lifting and scattering later this morning. Becoming mostly sunny later this morning through the afternoon (some high clouds may linger SE) with a light N wind. Forecast highs are in the mid to upper 70s, which are a few degrees above NBM, noting that statistical guidance shows highs in the upper 70s to around 80F.

A dry cold front slides N-S across the Mid-Atlantic tonight as high pressure builds SE from the Great Lakes. Low temperatures likely drop into the mid/upper 40s from the Piedmont to the MD Eastern Shore ranging to the mid/upper 50s across coastal regions of SE VA and NE NC. High temperatures Tuesday will be slightly below average and generally in the mid 60s to lower 70s. Tuesday night will be the coolest of the week (and of the season so far) with widespread lows in the 40s and 50s at the immediate coast as high pressure settles over the region. Some upper 30s are possible in rural and typically cooler locations in the Piedmont. High pressure shifts offshore Wednesday with high temperatures moderating back to near average, which are in the lower to mid 70s. The high shifts farther offshore Thursday with high temperatures rising into the upper 70s to lower 80s (potentially mid 80s away from the coast) ahead of another dry cold front. This cold front crosses the region Thursday night with temperatures trending down to near seasonal averages Friday and Saturday.

A very dry airmass arrives behind the cold front tonight. 00z/05 EPS/GEFS/GEPS ensemble guidance showing PW values falling to 35-50% of normal Tuesday and only 'recovering' to 50-70% Wednesday. A slight increase to 70-90% of normal is expected by Thursday ahead of the cold front, and then the airmass behind the front has a similar (lack) of moisture. Overall, dry conditions will prevail at least through Saturday.

KEY MESSAGE 2...Moisture does not return until late this weekend into early next week.

By late this weekend into early next week, there is a potential that moisture gets pulled northward from the western Gulf and then pushed eastward across the region ahead of a trough over the mid- Mississippi Valley. Confidence is definitely low with regard to details. However, global ensemble guidance does show PW values rising above normal, with some deeper moisture in the 700-300mb layer. Given this, a chc for showers returns to the forecast Sunday and Monday. Temperatures should remain near average late this weekend and early next week.

AVIATION /12Z MONDAY THROUGH FRIDAY/

As of 655 AM EDT Monday...

Weak low pressure and a stationary front linger offshore as of 12z. Meanwhile, a narrow ridge of surface high pressure was located over the Piedmont. Widespread MVFR/IFR cigs persist. Drier air is expected to gradually filter in from the N this morning, with cigs expected to lift between 13-15z (potentially MVFR at ECG to 16z). Primarily VFR with decreasing clouds after 15-16z (although some CI may persist for the SE terminals) with a N/NNW wind ~10kt, and locally gusting to near 20kt at SBY during the aftn. VFR under a mostly clear sky tonight. A dry cold front slides across the area tonight. This will likely result in a NNE wind of 10-12kt at ORF and ECG late tonight into early Tuesday morning, which could briefly gust to near 20kt.

Outlook: VFR conditions prevail Tuesday and continue through much of the week. The next chances for sub-VFR conditions are likely not until next weekend.

MARINE

As of 330 AM EDT Monday...

Key Messages:

- A brief period of elevated seas persist through this morning for the northern coastal waters where Small Craft Advisories are in effect.

- Northerly winds increase behind a reinforcing cold front tonight, with Small Craft Advisories in effect for the Chesapeake Bay and lower James River.

- Sub-SCA conditions prevail for the remainder of the week with high pressure in control.

Transient high pressure is situated west of the waters this morning, with an cold front and weak area of low pressure offshore. The pressure gradient has been a bit tighter than initially expected and northerly winds are generally 10-15 kt and occasionally a bit higher on the ocean. This is yielding a few gusts to 20 kt. As a result, seas are also a bit higher than than earlier forecasts and are likely around 5 ft N of Parramore Island, though observations in that vicinity are limited to the Bethany Beach buoy (which has been hovering around 5 ft for the past several hours). Given all of this, did issue a short-fused Small Craft Advisory for these higher seas for the northern two ocean zones through 11z/7 AM. The wind direction shifts to the NW this afternoon and this should allow for some decrease in the seas.

A stronger push of cooler and drier air arrives this evening into tonight as a reinforcing cold front pushes through the waters. Northerly winds increase to 15-20 kt across the Chesapeake Bay, lower James River, and coastal waters, with gusts to 25 kt also expected. Thus, a Small Craft Advisory has been issued for the Chesapeake Bay and lower James River from late this evening through early Tuesday morning. Seas are also expected to increase again, but there is some uncertainty if they will reach 5 ft. Most wave guidance suggests a peak around 4 ft in the 0-20 nm zones; however, would not be surprised if some 5 footers sneak in. Given the lower confidence, will hold off on advisories for the ocean at this time. This will be reevaluated with the afternoon forecast update. Waves on the Chesapeake Bay will average 2-4 ft tonight. Wind speeds should be in the 10-15 kt range elsewhere on the upper rivers and Currituck Sound. Northerly winds quickly decrease Tuesday afternoon as high pressure builds into the region from the NW. Sub-SCA winds shift to the south Wednesday and then southwest Thursday. A dry and weak cold front shifts the winds back to the N Friday. Limited cold advection should preclude the need for Small Craft Advisories behind this frontal passage. Seas decrease to 2-3 ft Tuesday afternoon and then hover around 2 ft for the remainder of the week.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Small Craft Advisory from 10 PM this evening to 10 AM EDT Tuesday for ANZ630-631. Small Craft Advisory from midnight tonight to 10 AM EDT Tuesday for ANZ632-634-639. Small Craft Advisory until 7 AM EDT this morning for ANZ650- 652.