Marine Weather and Tide Forecast for Lusby, MD

NEAR TERM /THROUGH TONIGHT/
Relative to yesterday, the local radar mosaic shows a much less active setup across the region. This is in response to a building mid/upper ridge which is settling over the central Appalachians into the Mid-Atlantic states. A rather subdued looking cumulus field is evident on the GOES-19 visible satellite channel. There are some localized enhancements across the Blue Ridge Mountains as well as along a west-east boundary stretching from St. Mary's County into central Virginia. Both of these areas have a modest signal for enhanced rainfall amounts.

Flood Watches remain in effect across Augusta, Nelson, Albemarle, and St. Mary's counties until midnight. This also includes the central Virginia Blue Ridge. This particular zone is where convection is generally ongoing, but is rather disorganized and more transient in nature. The limited upward growth is evidenced in the dearth of lightning activity.
However, flash flooding remains possible in these areas through the afternoon and evening hours, particularly as storms intensify. As noted by the precipitable water values averaging just above 2 inches, a tropical air mass remains in place across areas south of I-66. Given such an air mass, rainfall rates inside the watch area could approach 1.50 to 2.50 inches per hour.

For locations north of I-66, expect a mainly dry forecast through the remainder of the day. High temperatures across the region should top out in the mid/upper 80s to near 90 degrees.
With dew points ranging from the upper 60s to mid 70s, heat indices will largely be in the mid/upper 90s. Heading into the tonight, any convective chances to the south wane by after midnight. A mild and humid air mass persists with forecast lows in the upper 60s to mid 70s (60s for the mountains). Light winds combined with saturation of the low levels will support patchy fog, some locally dense. Areas that see heavy rainfall today and the more vulnerable low-lying river valleys have the best shot at dense fog.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/
As the upper ridge departs to the east, heights again lower on Wednesday in response to a combination of shortwaves and convective-induced perturbations. The energetics aloft will again move into the very moist and unstable environment across the Mid-Atlantic states. A preponderance of 12Z high-resolution models favor semi-robust convection across the region on Wednesday afternoon and evening. Not surprisingly, the placement of convective maxima vary from model to model, but the signal is certainly present. Area-wide precipitable water values return to the 2 to 2.25 inch range which is up around the 95th percentile and above for mid-July. This combination of identifiable forcing mechanisms with anomalous tropical moisture will enhance the risk of flash flooding on Wednesday. The Weather Prediction Center has upgraded much of the area into a Slight Risk for excessive rainfall. Flood Watches will likely be needed at some point given Wednesday's setup.

Severe weather is not completely out of the question either as the Storm Prediction Center has raised the risk area to a Marginal across much of the region. Taller thunderstorms will be capable of carrying water-loaded downdrafts to the surface which would bring a threat of damaging wind gusts. Any convective threats should wane after dark given the loss of diabatic heating.

On the temperature side, expect another typical summertime day with highs rising into the upper 80s to low 90s. Adding the persistent humidity in the air will carry heat indices to around 97 to 102 degrees. The only relief would come in the scattered to numerous thunderstorms across the region. Warm and humid conditions again persist into the night with low temperatures in the low/mid 70s. Like previous nights, patchy fog may develop across the region.

Moving into Thursday, the local area appears to be in between systems which should yield a reduced threat of convection.
However, temperatures do spike further with high temperatures pushing into the 90 to 95 degree range. Adding the persistent high dew points carries heat indices to around 100 to 105 degrees. This would near Heat Advisory thresholds so this bears some watching. Little to no relief is expected into the night with Thursday night's low temperatures well into the 70s (mid 60s to low 70s for mountain locales).

LONG TERM /FRIDAY THROUGH TUESDAY/
The longwave pattern across the CONUS should remain fairly consistent through the long term period, with zonal flow across the northern tier of states and subtropical ridging in place over the south. Multiple disturbances will pass to our north within zonal flow during the long term period. This will keep conditions active, with daily chances for showers and thunderstorms across the area. Temperatures will remain near average, with highs in the upper 80s to around 90, and lows in the upper 60s and lower 70s.

While an instance or two of damaging winds or flash flooding can't be ruled out any day, Friday appears to be the day with the greatest chance for damaging winds or flash flooding. A cold front will approach from the north and west that day as deep moisture pools ahead of the front and mid-level flow increases to around 25-30 knots.

AVIATION /18Z TUESDAY THROUGH SUNDAY/
With the focus for convection shifting to the south, only KCHO has convective groups in the TAF for today. At this point, any activity has been lacking so will monitor trends during the next shift. Otherwise, winds remain on the lighter side with some restrictions possible heading into the overnight hours. Patchy fog could yield some MVFR conditions, particularly across the more western terminals.

Wednesday is looking fairly active across the area with the potential for sub-VFR conditions at all TAF sites. There was enough of a signal to go with a prevailing -TSRA group at KDCA, KIAD, and KBWI between 20-00Z. A PROB30 group remains for the few hours before given the potential for earlier convective development. Otherwise, southerly winds increase through the day with possible gusts up to 15 knots. Like previous nights, patchy fog may develop. Convective chances decrease on Thursday, but cannot rule out brief restrictions as air mass thunderstorms pop up.

Prevailing VFR conditions are expected on both Friday and Saturday.
A thunderstorm could lead to brief restrictions either afternoon or evening. Winds will generally be out of the northwest on Friday, and out of the south on Saturday.

MARINE
Sub-advisory caliber winds remain for the next 24 hours given weak gradients. However, a ramp up is eventually expected during the second half of Wednesday into Thursday. The uptick in southerly winds may lead to some localized channeling effects, particularly across the southern-most waters. Small Craft Advisories may be needed from Wednesday evening into portions of Thursday as gusts rise to 20 to perhaps 25 knots.

A threat for convection on Wednesday will lead to some hazardous marine conditions, particularly during the afternoon/evening hours. Special Marine Warnings may be needed for any of the stronger storms. Convective chances decrease into Thursday, but some isolated to scattered storms may fire up during peak heating.

Sub-SCA level winds are expected on both Friday and Saturday. Winds will generally be out of the northwest on Friday, and out of the south on Saturday.

TIDES/COASTAL FLOODING
After a brief lull in the warm advection flow regime, expect a return to the prolonged period of southeasterly winds. This will lead to elevated tidal anomalies through midweek, particularly across Annapolis. This location will see Action stage at times, particularly during the higher of the two astronomical high tide cycles. However, outside of freshwater influences from heavy rainfall, the threat for tidal flooding appears low.

LWX WATCHES/WARNINGS/ADVISORIES
DC...None.
MD...Flood Watch until midnight EDT tonight for MDZ017.
VA...Flood Watch until midnight EDT tonight for VAZ025-036-037-508.
WV...None.
MARINE...None.