textproduct: Wakefield

WHAT HAS CHANGED

Updated aviation discussion for 12z TAFs.

KEY MESSAGES

1) Rain chances increase this morning, with locally heavy rain possible especially across SE VA and NE NC.

2) Dry with seasonable temperatures and lower humidity for the weekend. Showers and storms return Monday.

DISCUSSION

As of 255 AM EDT Friday...

KEY MESSAGE 1....Rain chances increase this morning, with locally heavy rain possible especially across SE VA and NE NC.

The remnants of TS Arthur are gradually lifting across the deep South. Meanwhile, a cold front associated with a strong low pressure system in the Northeast is draped across the Ohio Valley through the northern Mid-Atlantic region. Storms across our area have lulled, with the exception of one thunderstorm tracing the fringe of our northern counties. With the loss of daytime heating and the best environment for convection still to our SW, most of the rain has transitioned to stratiform this morning. Temperatures remain in the 70s to lower 80s closer to the coast, with dew points in the upper 60s to lower 70s, making for a somewhat muggy morning. The latest SPC mesoanalysis depicts a noticeable decrease in CAPE across the area since last evening, though some instability is expected to return later this morning. Even with some marginal instability, the threat for severe storms remains low through the day today, though a few stronger storms cannot be ruled out. The greater threat will be from moderate to heavy rain as the surface cold front drops in from the north, in tandem with the deeper moisture from the remnants of TC Arthur moving in from the SW. This will likely occur in a narrow band along the frontal zone, though the warm rain processes with the tropical moisture should make for highly efficient rain producers capable of producing briefly impressive rain rates. Some guidance has trended down in regards to QPF across our area/shifted the heaviest axis of rainfall to our south, but there still may be a narrow corridor across our area that sees 1-2" of rainfall between sunrise and midday today, with locally higher totals possible. Where this corridor of heaviest rainfall sets up is somewhat uncertain, but will likely be across SE VA/NE NC if it does occur across our area. Moisture slides offshore this afternoon, with quick clearing from NW to SE this afternoon into this evening.

KEY MESSAGE 2...Dry with seasonable temperatures and lower humidity for the weekend. Showers and storms return Monday.

Subsidence develops in the wake of the departing low this evening, with weak high pressure settling across the region for the upcoming weekend. GEFS and Euro ensembles show PWAT values dropping down to about 50% to 60% of normal, leading to dry weather and seasonable temperatures with highs in the 80s to lower 90s and lows mainly in the 60s. The next system is set to affect the area Monday with shower and storm chances returning, along with higher humidity. The timing of the frontal passage with the system will once again dictate the amount of convection the area sees. Otherwise, only slight to low-end moderate chances for rain and near to slightly above normal temperatures are forecast through the end of next week at this time.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

As of 645 AM EDT Friday...

Light to moderate rain is overspreading most terminals this morning, with some VIS reductions and lowered CIGs developing within the rain. Have included MVFR/IFR flight restrictions area-wide from 09/12Z to ~16-21Z this afternoon, lingering the longest at the SE terminals. Though there will likely be thunderstorms near the terminals, the timing and location is somewhat uncertain, so have not included mention in most TAFs (aside from ECG) at this time. Winds shift to the N-NE in the afternoon as conditions improve as showers move offshore and CIGs start to lift, with light winds expected overnight.

Outlook: Drier conditions/VFR conditions prevail Fri evening through the upcoming weekend. Shower/storm chances return Monday.

MARINE

As of 255 AM EDT Friday...

Key Messages:

- Low-end Small Craft Advisories have been issued for the southern Chesapeake Bay and Lower James River for this morning for W-SW winds ahead of a cold front.

- SCA level northerly winds appear unlikely behind the front this afternoon, as guidance has backed off on this potential since yesterday.

- Benign marine conditions are expected over the weekend with SCAs likely on Monday/Monday night with southerly winds.

Showers and a few storms crossed portions of the marine area earlier tonight ahead of the remnant low of TS Arthur, which is in western NC and tracking eastward. Meanwhile, a cold front remains to our north and is slowly dropping south toward the local area. We saw a surge of SW winds (to 15-25 kt with a few higher gusts) during the past couple of hours as more moist, higher theta-e air moved in well ahead of the remnant low. Winds have since diminished to 10-15 kt with occasional 20 kt gusts. The remnant circulation from TS Arthur expected to quickly track eastward across NC and move offshore later today. At the same time, the previously referenced cold front drops southward across the local waters with W/SW flow becoming N and NW behind the boundary. A modest increase in the pressure gradient over the next few hours ahead of the remnant low/cold front is expected to allow the W-SW winds to increase to 15 kt with frequent gusts up to 20 kt (highest over the lower bay and possibly lower James). Occasional gusts to 25 kt are possible later this morning, mainly at elevated locations. As such, have issued marginal SCAs for the lower bay and lower James from 4 AM-noon. There is also a chance of convectively enhanced winds this morning/early afternoon (mainly south), which would be handled separately with MWSs/SMWs if needed. While the guidance yesterday had a brief, stronger surge of northerly winds behind the cold front during the afternoon, the 00z models have backed off on this. Therefore, have ended SCA headlines at noon. NW winds 10-15 kt are expected to continue into early Saturday. High pressure builds into the region Saturday into Sunday with southerly flow expected to strengthen ahead of the next system early next week. SCAs appear likely for much of the marine area from Monday through Monday night.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until noon EDT today for ANZ632-634-639.