textproduct: Wakefield

WHAT HAS CHANGED

Timing for morning showers has trended slightly later and linger into the afternoon for northern sections.

The Friday night/Saturday cold front has also trended slightly later, with higher rain chances lingering well into Saturday, and potentially into early next week along the coast.

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

KEY MESSAGES

1) A cold front drops southward this morning with increasing clouds and much cooler temperatures. Some light rain is forecast across the northern half of the area.

2) Warm and breezy Friday with gusty showers along the front Friday night into Saturday. Much cooler temperatures arrive this weekend.

DISCUSSION

As of 310 AM EDT Thursday...

KEY MESSAGE 1...A cold front drops southward this morning with increasing clouds and much cooler temperatures. Some light rain is forecast across the northern half of the area.

Surface observations show a cold front translating southward across the area as high pressure builds in from the NW. Satellite shows quite a bit of mid level cloud cover moving into the region. Radar shows some very light returns in the Piedmont but little if any precip is making it to the ground. Expect the front to continue southward through the morning with winds becoming NE as high pressure to the north allows for CAD to develop across the region. Becoming a bit breezy near the coast today. 00z guidance has continued the trend of shaving a degree or two off of previously forecast temperatures behind this backdoor front. Highs range from the mid 60s N, upper 60s to low 70s along S of I-64, and upper 70s to low 80s near and S of the VA/NC border. High temps will occur in the morning for the northern half of the area with temps holding steady or slowly falling thereafter as CAD strengthens. It still appears that there will be an uptick in precip coverage across the NW and N this morning into the afternoon. QPF will be light with 0.1- 0.15" across the north, tapering to a few hundredths near Richmond and little to nothing south of US-460. Some light rain or drizzle may linger into tonight, mainly for the Northern Neck and Eastern Shore. Low temps range from the upper 50s NW to the mid/upper 60s SE.

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

Today's front will lift northward as a warm front on Friday, scouring out the low level stable CAD airmass as an upper trough digs into the Midwest and strengthens a surface low over the eastern Great Lakes. High temps rebound into the mid and even upper 80s with breezy SW winds. It now appears that the daylight hours of Friday will be dry with the 00z models continuing to slow the progression of the strong front. PoPs increase after sunset, along and ahead of the surging cold front. Hi-res guidance shows the potential for thin strongly-forced line of convection along the front Friday evening. With the somewhat slower frontal timing, even less instability is available than it looked 24 hours ago. However, strong kinematics aloft will likely be able to mix down to the surface with wind gusts 30-40 mph possible as the front comes through. SPC has maintained a Marginal Risk (level 1/5) across the the N and NE portions of the area for strong to severe wind gusts. There will be little if any thunder with these showers despite the potential for strong wind gusts.

Models have continued to trend toward a more amplified upper level pattern across the SE CONUS this weekend. The NAM and ECMWF are the most bullish, developing a closed upper low and coastal surface low while the GFS/Canadian models are much more progressive. This bimodal split in the guidance leads to significant uncertainty regarding the sensible weather this weekend and likely well into next week. Regardless, it still appears that much colder air will spill into the area Saturday and Sunday with high temps in the mid 50s NW to the low/mid 60s SE. Rainfall chances and placement are where the highest uncertainty lies. The amplified solutions would result in rainfall continuing on Saturday and lingering potentially into early next week as low pressure lingers offshore. Have trended PoPs and QPF toward the coastal low scenario but with very low confidence at this time. Cold overnight lows Saturday night still appear on track but with more wind likely to diminish the potential for frost, even in the typically colder Piedmont spots.

AVIATION /09Z THURSDAY THROUGH MONDAY/

As of 550 AM EDT Thursday...

VFR conditions start the 12z/15 TAF period. A cold front is currently dropping south across the region with increasing clouds and northerly winds behind the boundary. Some light returns are noted on radar across the far northern counties. Clouds will continue to spread south and thicken/lower toward sunrise. MVFR CIGs likely at RIC around 15z, spreading south and east to PHF, ORF, and ECG in the 16-17z timeframe. SBY sees MVFR by mid to late afternoon along with a chance for light rainfall. RIC will also likely see some rain but lower confidence in timing/coverage. The remaining terminals are forecast to stay mostly dry but a shower or two may impact PHF. Winds become NE this morning and increase to 5-10 kt inland and 10-15 kt with gusts 15-20 kt at PHF and ORF by mid morning. Lower-end MVFR CIGs this afternoon will approach IFR thresholds early this evening with IFR forecast tonight. Guidance also suggests some VSBY restrictions after midnight before the front starts to lift back to the north.

Outlook: The front will lift back north of the area Friday, allowing a return to VFR conditions. Breezy SW winds develop by late morning and persist through the day. 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, especially E.

MARINE

As of 310 AM EDT Thursday...

Key Messages:

- NE winds increase behind a backdoor cold front this morning. Small Craft Advisories are in effect 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.

A backdoor cold front is dropping across the region early this morning, but hasn't quite made it to the local waters as ~3am obs. Obs still show WSW winds around 10kt, seas around 2ft, and waves in the bay around 1ft. Winds will gradually become NE behind the front from N to S between this writing and ~8/9am. These winds will be breezy and near or just above advisory criteria at 15-20kt. Winds should peak around mid-morning with highest winds over coastal waters north of Cape Charles and in the lower Ches. Bay. Small Craft Advisories are unchanged from the previous issuance and are in effect for the nearshore coastal waters north of Cape Charles, the mouth of the bay, and the lower bay. Winds diminish during the late afternoon into the evening becoming easterly. Southwest flow then returns early Friday morning ahead of the next front.

SSW flow ramps up to 15-20kt again on Friday as the pressure gradient tightens ahead of the stronger front. Strong CAA behind the front over the still-warm waters will lead to windy conditions. Confidence is high in at least strong SCA conditions with confidence in gale-force gusts continuing to increase. North winds increase to 25-30kt behind the front with gusts potentially as high as 40kt. Local wind probs continue to show 70-90% for 34kt+ gusts for much of the Ches Bay and especially the coastal waters south of Cape Charles for Saturday. Winds become more NE and remain in at least the strong SCA range through Sunday morning. Still just a bit early for Gale Watches, but they will likely be going up soon. Seas are also expected to increase substantially and could possibly exceed 6-9 ft. Uncertainty is increased past early Sunday, though, now that the possibility of coastal low pressure developing has been introduced by guidance. There is still a large spread in the strength and positioning of this potential low, which of course has a large impact on the winds. Previous forecasts had winds dropping off quickly Sunday as high pressure built in behind the front, but deepening low pressure along the coast would mean a continuation of strong onshore flow into early next week. Regardless, onshore flow of some sort looks to remain for much of the next week, so elevated seas will probably take a while to come down to below advisory level.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 4 PM EDT this afternoon for ANZ632- 634-654. Small Craft Advisory until 4 PM EDT this afternoon for ANZ650- 652.