Dumbarton, VA Weather

What Has Changed

Updated aviation discussion for 00z/21 TAF period.

Continued the trend of the previous forecast by lowering overnight temps through most of the upcoming week. Also, increased daytime highs a few degrees given trends from the past few days. Dew points have also been lowered, which yields lower daytime minimum relative humidity values.

The Gale Warning for the Currituck Sound has been replaced with a Small Craft Advisory.

Discussion

As of 315 PM EDT Tuesday...

KEY MESSAGE 1...Breezy, sunny, and dry fall weather continues this week.

An expansive area of high pressure stretches from the Gulf Coast northward into southern Ontario and Quebec this afternoon. The pesky low pressure system remains offshore (stacked under an upper low), though visible satellite imagery shows all the clouds associated with this system offshore of the region. Overall, a beautiful day across our CWA this afternoon with temperatures in the upper 60s to lower 70s and dew points in the 30s and 40s. Breezy conditions continue along the coast where the pressure gradient remains compressed between the high and low pressure systems. Another chilly night with lows by Wednesday morning in the low to mid 40s, except staying in the 50s along the coast where the northerly breeze off the water will moderate the temperatures.

Similar synoptic pattern and resultant wx continues for the remainder of the week. Most model guidance suggests the low will probably retrograde back toward the coast by ~50 miles tonight into Wednesday. Therefore, breezy conditions are likely to continue at the coast. There could also be some increase in stratocumulus for the eastern ~third of the area for most of the day tomorrow. Temperatures will generally be a few degrees cooler than today and range from the lower 60s at the coast to the mid to potentially upper 60s inland. The stacked low offshore finally departs to the northeast at a brisk speed by Wednesday night. This is as it gets a kick from a digging, northern stream trough over the northeast CONUS and SE Canada. High temps Thursday into the weekend will be in the 60s for most, with overnight lows in the upper 30s to mid 40s inland and upper 40s to lower 50s at the coast. The dry wx persists through the weekend and likely into next week as well.

KEY MESSAGE 2...Prolonged onshore flow will lead to multiple elevated tide cycles this week resulting in rounds of coastal flooding.

Generally 1-2 foot anomalies across the lower bay and ocean this afternoon and slowly rising as water levels build due to the persistent north to northeast wind leading to some nuisance to minor tidal flooding across the advisory area today. Due to the astronomical tides being lower with tonight's high tide cycle, am expecting similar flooding with the overnight high tide as the anomalies are forecast to be a little higher than today.

Aviation

As of 730 PM EDT Tuesday...

VFR conditions prevail for the 00z/21 TAF period. Clear skies are observed and will continue through the period. Winds will be 5-10 kt overnight, except 12-17 at ORF/ECG. Gusty winds will return Wednesday morning with gusts to 20-25 kt across all terminals. Additionally, some lower clouds are likely to approach the coast in the morning, but model guidance keeps these clouds away from our local terminals through 18z.

Outlook: VFR conditions and breezy N winds are expected to prevail through the week.

Marine

As of 315 PM EDT Tuesday...

Key Messages:

- No significant forecast changes. Small craft advisories remain in the rivers while gale warnings remain in the coastal waters.

- Brief lull in winds today, however they may increase slightly especially over the coastal waters tonight as the offshore low deepens and shifts slightly to the west.

- The low gradually moves northeast starting Thursday leading to a slow decrease in wind and waves into the weekend.

A lull in the winds this afternoon with most areas in the bay gusting to 25 kt and the coastal waters gusting to 30-35kt. Models suggest that the offshore low will deepen tonight and possibly shift westward. This may allow for a slight increase in winds especially beyond 10 nm from shore. With this in mind, have opted to leave the gale warnings in place despite the current observations not showing any gale force conditions at this time. Nonetheless, we the gales will likely be confined to areas beyond 10 nm offshore and not impact the very nearshore or anywhere in the Chesapeake Bay. Local 34kt wind gust exceedance probabilities show near 0% at the mouth of the bay, 60 percent at Chesapeake Light and >80% offshore at the canyons.