Chesapeake Bay from Drum Point MD to Smith Point VA Marine Forecast
|Rest Of This Afternoon...Nw Winds 10 Kt. Waves 2 Ft.|
|Tonight...Sw Winds 5 To 10 Kt. Waves 1 Ft.|
|Fri...Sw Winds 10 To 15 Kt...Becoming S With Gusts To 20 Kt Late. Waves 1 Ft...Building To 3 Ft In The Afternoon.|
|Fri Night...S Winds 15 Kt With Gusts To 25 Kt. Waves 3 Ft.|
|Sat...Sw Winds 10 To 15 Kt With Gusts To 20 Kt. Waves 2 To 3 Ft.|
|Sat Night...W Winds 10 Kt. Waves 2 Ft. A Chance Of Showers And Tstms.|
|Sun...Sw Winds 5 To 10 Kt. Waves 1 To 2 Ft.|
|Mon...Sw Winds 5 To 10 Kt. Waves 2 Ft. A Chance Of Showers. Winds And Waves Higher And Visibilities Lower In And Near Tstms.|
| Area Forecast Discussion|
National Weather Service Baltimore MD/Washington DC
252pm EDT Thu Jun 17 2021
High pressure will remain in place over our region through Friday. A backdoor front will move into our region on Saturday and remain in place through Sunday. Another front will move through our region early next week. High pressure builds in by Wednesday.
Near Term - Through Friday Night
Skies have been clear through the early parts of this afternoon as high pressure remains in place at the surface along with upper level ridging building aloft. A general northerly flow has lead to drier and cooler air being advected into our region. Our morning sounding indicates that near record low PW's were being observed throughout the layer which shows dryness of the current air mass. Temperatures are currently running in the low to mid 70s with highs this afternoon expected to peak in the mid to upper 70s with a few areas reaching the 80 degree mark.
High pressure overhead begins to shift eastward over the eastern seaboard this evening. The northerly flow that the region experienced today will slowly become southerly overnight. Weak moisture advection will begin late this evening and into early Friday morning. The rising dewpoints will prevent overnight temperatures dropping as low as this morning with low temperatures expected to be in the mid 50s across the region.
High pressure will shift off-shore on Friday leading to increasing advection of warm and moist air into our region. The flow at 850 will increase out the south which will lead to rising moisture throughout the layer and increasing mid level cloud cover on Friday. Conditions will remain dry throughout the day on Friday but afternoon temperatures will be much warmer with highs running in the mid to upper 80s.
A shortwave trough is forecast to approach from the northwest late this evening and into Saturday. High Res models have this shortwave kicking off a MCS over western Ohio during Friday afternoon and moves it eastward toward our region Friday evening. Most guidance has the MCS dissipating as it moves across our region but areas along and west of the Allegheny Front will have the potential to see periods of heavy rain and possibly a strong thunderstorm. Our western MD areas are currently in a marginal risk for a flood and SVR threat. I believe the risk for any showers or storms moving east of the Allegheny front will be pretty low due to the drying deep layer of westerly winds. Overnight lows will be very mild in the mid to upper 60s to lower 70s.
Short Term - Saturday Through Saturday Night
The showers and thunderstorms that will affect the western areas of our forecast area early Saturday morning will dissipate by daybreak. An upper level trough will move north of our region on Saturday with and an upper level jet becoming positioned over PA. A backdoor front is forecast to approach from the north later in the day on Saturday. Continued warm air advection ahead of the frontal passage will lead to increasing CAPE values upwards of 2000. Winds are forecast to increase at 850 which will lead to a moderate shear environment during the afternoon and evening periods on Saturday. The combination of the approaching front along with moderate shear and CAPE will lead to a risk for strong to severe thunderstorms on Saturday. It seems high res models are highlighting the area along the MD and PA border with storms mainly in the afternoon. There remains some uncertainty on the impact of strong westerly flow which could potentially dry out the layer especially further southward into our region. Afternoon temperatures are forecast to peak in the mid to upper 80s to lower 90s with overnight lows in the 60s and lower 70s.
Long Term - Sunday Through Thursday
The long term period will feature an extended stretch of active weather across the region. Starting out on Sunday, we'll reside in zonal aloft. There won't be much in terms of large scale forcing for ascent across the region on Sunday, but daytime heating, terrain circulations, and the bay breeze may be enough to initiate some storms Sunday afternoon within a weakly capped environment. Appreciable instability will build within the hot and humid environment (around 2000 J/kg). Flow will be relatively weak (effective shear values around 20 knots), but enough to give storms a little organization. Overall coverage of storms should be much lower than Saturday in the absence of large scale forcing for ascent, but a few stronger storms can't be ruled out. Temperatures on Sunday will top out in the upper 80s to around 90, and it will become quite humid, with dewpoints around 70.
The pattern will remain active heading into Monday and Tuesday as a powerful trough digs to our west and tropical moisture streams northward in advance of the trough. Monday's forecast will largely be dependent on the track of a tropical disturbance currently in the Gulf, as it tracks toward the area from the southwest. If the disturbance remains suppressed well off to our south, it could be a relatively quiet day, but if it tracks overhead or just to our south, it could be an active day, with heavy rainfall and flooding both potential threats. There's still a considerable amount of spread in model guidance with respect to this system, so we will continue to refine our forecast as confidence in the track of the system gradually increases over time.
Flow aloft will increase heading into Tuesday as an impressive trough by June standards approaches the area from the west. While there is still a considerable amount of spread in guidance with respect to the details, thunderstorms look likely across the area, with potential threats for both severe thunderstorms and flash flooding, barring a large shift in the forecast. Continued heat and humidity is expected early next week, with high temperatures in the upper 80s to lower 90s and dewpoints in the upper 60s to near 70.
Conditions will turn much cooler and drier by Wednesday as the aforementioned trough progresses off to our east, driving a strong cold front through the area as it does so. Temperatures may struggle to get out of the 70s on Wednesday, with dewpoints crashing into the 40s and 50s.
SubSCA (Small Craft Advisory) conditions expected today but as winds become southerly on Friday, Small Craft Advisories will likely be needed Friday afternoon and into Saturday.
Sub-SCA (Small Craft Advisory) level winds are expected on Sunday. Winds will increase out of the south on Monday and could approach SCA (Small Craft Advisory) levels. Showers and thunderstorms appear possible both days.
NOAA Baltimore MD/Washington DC Office: Watches - Warnings - Advisories
DC...None. MD...None. VA...None. WV...None. MARINE...None.