textproduct: Wakefield

WHAT HAS CHANGED

Updated discussion.

Timing for morning showers tomorrow have trended slightly later, and are mainly confined to northern sections.

The Friday night/Saturday cold front has also trended slightly later, with cooler temperatures and higher rain chances therefore now forecast Saturday morning.

A Small Craft Advisory is now in effect for the northern nearshore coastal waters and the lower Chesapeake Bay.

KEY MESSAGES

1) Very warm, record breaking temperatures this afternoon quickly give way to increasing clouds and a much cooler day Thursday.

2) Warm and breezy Friday with a few gusty showers Friday night into Saturday. Much cooler temperatures arrive this weekend.

DISCUSSION

As of 310 PM EDT Wednesday...

Very warm, record breaking temperatures this afternoon quickly give way to increasing clouds and a much cooler day Thursday.

Latest surface analysis reveals ~1020 mb surface high pressure centered over the western Atlantic. To the north, a wavy front remains draped over the northern mid-Atlantic into New England. To the west, a chilly 1024+ mb high is centered over the Northern Plains, and will push into the Upper Midwest by this evening. Aloft, an upper ridge centered over the west-central Gulf coast extends into the local area. The rising heights are allowing unseasonable warmth across the region. Upstream, a closed low over the Four Corners region will be absorbed into a northern stream trough which will drop across the Canadian Prairies tonight into tomorrow. It is this system which will bring sharply colder air to the region this weekend.

Locally, temperatures are well into the 80s to around 90 at 19z. Several local records for the date have already been broken. These have been included below for reference.

High pressure to the north will slowly build across the Great Lakes and New England tonight and early Thursday, slowly pushing the front to the north closer to the area. That front will cross into the region Thu morning. Clouds will increase overnight, with mostly cloudy conditions then persisting through tomorrow evening. A few showers could accompany the front as it pushes into the area late tonight, but the frontal passage should be mainly dry.

The surface high ridges down the eastern slope of the Appalachians Thursday, allowing a CAD wedge to develop. High-res guidance continues to trend cooler for tomorrow and highs have been nudged slightly down given the persistent overcast conditions and chilly NE flow. Weak isentropic lift across the northern zones will primarily reinforce the developing stratus, it could also allow for some light sprinkles or light rain tomorrow morning. Highs near and south of the VA/NC line will rise back into the 70s to near 80 with clouds being a bit thinner and slower to arrive. Farther north, especially N of I-64, temperatures will follow a non-diurnal temperature curve with highs realized in the morning or by midday before leveling off or even falling off slightly.

KEY MESSAGE 2...Warm and breezy Friday with a few gusty showers Friday night into Saturday. Much cooler temperatures arrive this weekend.

The Canadian deep upper trough is forecast to dig across the Great Lakes Thursday night into Friday with a strengthening surface low over the Ohio Valley. Southerly flow ahead of this feature will allow the front to lift back northward as a warm front Friday morning. High temps rebound into the low 80s N with mid and upper 80s S. It will become breezy out of the SW by Friday afternoon. A rapidly deepening low pressure will translate NE into New England on Friday with a strong cold front extending back to the southwest. This front will cross the local area late Friday evening into early Saturday with significant cold advection moving into the region. Trends from the past few cycles of probabilistic guidance, along with the ECMWF/CMC deterministic runs are favoring a stronger shortwave trough which digs farther south into the mid-Atlantic. This results in a slightly slower progression of the front late Friday night and Saturday. While QPF remains light steep low- level lapse rates and vigorous momentum transfer could mix down 35-40 mph gusts to the surface fairly easily coincident with the frontal passage. Otherwise, while favorable kinematics support storm organization, meager moisture/instability and now later nocturnal timing all significantly limit severe potential beyond the previously referenced gusty frontal wind threat.

Strong (1035mb+) high pressure builds into the region behind the front with upper troughing remaining over the eastern CONUS, resulting in well below normal temperatures this weekend. Given the delayed timing and subsequent onset of cold advection, Sat highs are also likely to be realized early in the day. Afternoon temps likely remain more or less steady even with gradual clearing, with upper 50s to low 60s S/SE. It will also remain quite breezy on Saturday with gusts 25-30 mph, and especially near the coast where winds could gust 30-35 mph. Overnight low temps tumble into the mid to upper 30s in the Piedmont with low to mid 40s for the remainder of the area Saturday night. Upper 30s and low 40s are forecast Sunday night into Monday. Some frost is possible in the Piedmont with this airmass, especially if temps continue to trend toward the cooler MOS guidance which shows temps in the low 30s in the typically cooler spots.

AVIATION /19Z WEDNESDAY THROUGH MONDAY/

As of 140 PM EDT Wednesday...

VFR across the region to begin the 18z TAF period will persist through tonight, though some MVFR CIGs will be possible toward the tail end of the period late tonight. SW winds 5-10 kt this afternoon under a mainly sunny sky. A cold front drops south toward the region this evening, and will cross the terminals overnight tonight into early Thu morning. Winds becoming N then NE behind the boundary. Increased cloud cover and wind gusts to 15-20 kt are forecast post-frontal, along with a low-end rain chances for RIC and SBY. MVFR CIGs will develop Thu morning and early afternoon, potentially briefly improving back to low-emd VFR before MVFR to IFR CIGs return Thursday evening into early Friday morning as a cool air wedge pattern develops over the area.

Outlook: The front will briefly lift back north of the area, allowing a return to VFR conditions Friday, with breezy SW winds developing in the warm sector. However, deteriorating flying conditions return later Fri evening through Sat evening as a second, stronger cold front crosses the area. Additional rain chances and gusty NW winds are expected Sat morning into the afternoon post-frontal. VFR conditions return early Sunday morning through Monday.

MARINE

As of 305 AM EDT Wednesday...

Key Messages:

- NE winds increase behind a backdoor cold front Thursday. Small Craft Advisories have been issued for the coastal waters N of Cape Charles and the lower Chesapeake Bay.

- A longer-duration wind event is likely along and behind a strong cold front beginning later Friday, potentially lingering through most of the weekend. NNW winds will likely frequently gust over 34 kt for a period of time.

High pressure is centered south of the area this afternoon. Winds across the local waters are generally light out of the S-SW, but have become locally variable near the coast of S VA where a weak sea breeze is attempting to develop. Quick changes are coming late tonight into Thursday as a backdoor cold front drops southward, with an abrupt shift in winds to the NE -- first across the N just before sunrise and then by mid-late morning across the S. Wind speeds are also forecast to increase to 15-20 kt. The highest confidence in gusts to 25 kt are in the southern Chesapeake Bay and coastal waters N of the NC/VA border. These NE wind events also tend to lead to higher seas than forecast by the numerical wave guidance, so am currently expecting seas to peak in the 4-5 ft range N of Cape Charles. Therefore, issued a Small Craft Advisory for the coastal waters N of Cape Charles for those higher seas and ~25 kt gusts and for the lower Chesapeake Bay for 20-25 kt gusts and 2-4 ft waves. These higher winds will be rather short-lived, gradually diminishing later in the day on Thursday. SCAs are in effect through the early afternoon hours. The front will lift back N as a warm front Thursday night/early Friday morning with winds quickly becoming S-SW by Friday.

By later Friday, low pressure is forecast to track into interior New England, with a sharp cold front extending SW. This front is still expected to pass through the area in the Friday-Saturday timeframe. However, there has been some changes in the model guidance over the past 12-24 hrs, including a trend toward a later frontal passage and a longer duration in the elevated N/NNW winds. The peak winds now look to occur during the day Saturday, but could certainly extend into the Saturday night and Sunday timeframe. The 12z ECMWF and NAM also now depict sfc cyclogenesis offshore of the OBX Sunday and the low lingers offshore through Monday on the ECMWF. Should this occur, marine impacts could be more significant and/or longer than currently depicted in the forecast. Suffice to say there is low confidence in the specifics during this period and users and encouraged to keep updated on forecast updates over the next couple of days. Regardless, Gale headlines seem quite likely at some point, but will continue to hold off on any watches due to the later timing and aforementioned confidence reasons. Seas are also expected to increase substantially and could possibly exceed 6-9 ft. Winds/seas should begin to gradually subside after Monday.

CLIMATE

Daily Record High Temperatures have already been established at area climate sites:

10/14 RIC 87/1975 (Already Broken: High of 90 as of 3 pm/Wed) ORF 86/1975 (Already Broken: High of 88 as of 3 pm/Wed) SBY 86/1975 (Already Broken: High of 89 as of 3 pm/Wed) ECG 86/1975 (Already Broken: High of 88 as of 3 pm/Wed)

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Small Craft Advisory from 7 AM to 4 PM EDT Thursday for ANZ632- 634-654. Small Craft Advisory from 4 AM to 4 PM EDT Thursday for ANZ650- 652.