Delaware Bay south of East Point NJ to Slaughter Beach DE Marine Forecast
|Tonight...Nw Winds Around 5 Kt, Becoming Sw Late This Evening And Early Morning, Then Becoming N Late. Waves 2 Ft Or Less. A Chance Of Tstms.|
|Thu...Ne Winds Around 5 Kt, Becoming E Late. Waves 2 Ft Or Less. A Chance Of Tstms Early In The Morning, Then A Chance Of Showers In The Late Morning And Afternoon.|
|Thu Night...E Winds 5 To 10 Kt. Waves 2 Ft Or Less. A Chance Of Showers In The Evening.|
|Fri...Ne Winds 5 To 10 Kt, Becoming N Late In The Morning, Then Becoming Se In The Afternoon. Waves 2 Ft Or Less. A Chance Of Showers In The Late Morning And Afternoon.|
|Fri Night...S Winds 5 To 10 Kt, Becoming Se After Midnight. Waves 2 Ft Or Less. A Chance Of Showers.|
|Sat...Ne Winds Around 10 Kt. Waves 2 Ft Or Less. A Chance Of Showers.|
|Sat Night...Ne Winds 5 To 10 Kt. Waves 2 Ft Or Less.|
|Sun...E Winds Around 10 Kt. Waves 2 Ft Or Less.|
|Sun Night...Se Winds 5 To 10 Kt. Waves 2 Ft Or Less.|
|Mon...Se Winds 5 To 10 Kt. Waves 2 Ft Or Less.|
|Mon Night...S Winds Around 10 Kt. Waves 2 Ft Or Less In The Evening. Winds And Waves Higher In And Near Tstms.|
| Area Forecast Discussion|
National Weather Service Mount Holly NJ
330pm EDT Wednesday July 6 2022
A frontal boundary will push south through the area tonight then stall out on Thursday morning. A remnant convective system will bring scattered showers and a few thunderstorms to the area on Thursday. On Friday, another front will approach the area from the north then cross through the region Friday night. High pressure will build into the area beginning on Saturday bringing drier and more pleasant conditions through Monday. The high pressure will shift offshore late Sunday into Monday then another cold front will approach the region Tuesday into Wednesday bringing a return of warmer and more humid conditions along with chances of showers and thunderstorms.
Near Term - Through Thursday
An unsettled forecast on tap for the next 24 to 30 hours.
A cold front has made it through northern New Jersey and the Lehigh Valley before getting hung up around the Fall Line. It should make it down to the I-195 corridor or so where it will become nearly stationary through Thursday. North of the front, surface dew points will be in the low to mid 60s or so, and south of the front, dew points will be in the upper 60s to low 70s, with dew points possibly in the low to mid 70s in portions of Delmarva.
Scattered showers are forming on that front, and scattered showers and thunderstorms will continue to develop into this evening as some weak shortwave energy passes through the region. Storms may intensify over Delmarva going into the evening, as dew points are in the low 70s there, and PWATs (Precipitable Waters) are up around 2 inches. Locally heavy rain is possible. SBCAPE values are up around 1500 to 2000 J/kg, but there really is not much lift associated with those shortwaves. Not expecting severe weather going through the evening.
Most activity will taper off by midnight or so, and some showers may continue to pass through the region during the overnight.
There is an area of low pressure that will approach late tonight and into Thursday morning. The problem is models do not quite have a good handle on it. The 12Z/06 NAM is quite aggressive with widespread showers and thunderstorms with heavy rain developing right over the area and continuing into Thursday afternoon. The 12Z/06 GFS has that low a bit farther south, with a bullseye of Quantitative Precipitation Forecast over the Delmarva Peninsula. 12Z/06 HRRR, FV3, and WRF-ARW are also much less aggressive than the NAM, and are father south. So the NAM appears to be an outlier. Will go ahead and carry slight chance Probability of Precipitation up north, and high chance Probability of Precipitation down in Delmarva. With high pressure establishing itself near the Gulf of Maine, this will allow for a cooler airmass to spread into the region. Highs will be in the upper 70s to low 80s. These cooler temperatures should also cut back on the instability needed for convection. Will carry showers, with a slight chance for thunderstorms focused on Delmarva.
Will have to keep an eye going forward for the upcoming 18Z and 00Z NAM to determine if the 12Z NAM was an outlier, or if it caught on to something that warrants further investigation.
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... The northwesterly flow pattern will continue from Thursday night through Saturday as will the periodic chances for showers and thunderstorms. The latest trends in the guidance suggest that Thursday night through early Friday will be largely dry, contrary to the previous forecast, although some isolated convection is possible. This is due to a farther south and faster progression of the frontal boundary that has been in the vicinity for a few days now. This was the only wholesale change that was made to the forecast in the short term period in addition to lowering the forecast low temperatures for Thursday night by a few degrees.
Guidance has come into a better consensus that the greatest chance for showers and thunderstorms in the period will be from mid-Friday afternoon through Friday evening as a remnant MCS/MCV moves toward the area out of the Ohio Valley. PWATs (Precipitable Waters) will once again make a run at 2" by late Friday and so heavy rain and localized flood could be potential threats depending on how the timing all shakes out. MUCAPE values below 1,000 J/kg should result in a minimal severe threat despite modest deep layer shear around 30 kts. highs Friday will be mainly in the mid 80s with lows ranging from the mid 60s to around 70 degrees.
Drier air will finally begin advecting into the area by late Saturday bringing a relief to the muggy conditions of this week. High temperatures are expected to be a few degrees below normal in the low to mid 80s. The dry air will bring a lessening chance for showers from north to south as the day progresses, but a couple showers are possible south of Philly.
Long Term - Saturday Night Through Wednesday
The strong upper ridge will continue to hold across much of the central US through the day on Sunday with the upper low/trough remaining off to our east; thus we hold in the prevailing northwest flow pattern. At the surface, the stalled boundary that has been lingering to our south will finally exit the area Sunday and surface high pressure will build and remain in control keeping the region dry through through Monday night. A weak shortwave diving southeast may try to increase cloud coverage a bit during the day Sunday, but the surface high and very dry low levels will preclude any precipitation development. Sunday morning we could see temperatures drop to near 50 across the northwest zones as a result of radiational cooling with clear skies and generally weak winds. Guidance then indicates that the upper low will pivot off to the northeast, allowing the ridge to nose a bit further into our area resulting in height rises to near 585 dam on Monday. Highs Sunday and Monday should be seasonable in the low to mid 80s, though Monday will likely be the warmer day as a result of the aforementioned height rises and 850 mb temperatures near 15C.
Overnight Monday into Tuesday, another upper level low and associated trough will develop and extend south from northern Canada. This will result in more zonal flow for our region as the trough works to flatten the ridge and embedded vorticity advection rounds the base of the trough. A surface trough/weak cold front looks to approach from the northwest sometime Tuesday into Tuesday night, though guidance remains somewhat spread on the timing at this point. Included chance Probability of Precipitation at this point for Tuesday night into early Wednesday morning as support for lift will exist, though recent runs of the GFS and Canadian indicate a potential longer period of precipitation extending through much of the day Wednesday. These details will continue to be ironed out. Long term trends point towards gradually increasing temperatures topping out in the upper 80s through mid-week.
Overall, sub-Small Craft Advisory conditions tonight through Thursday. Scattered showers and thunderstorms may result in reduced visibilities this evening through Thursday. Variable winds around 10 kt, becoming E to NE tonight through Thursday.
Outlook... Thursday night through Sunday...Sub-SCA (Small Craft Advisory) conditions are expected with scattered showers and thunderstorms possible through early Saturday. Winds will prevail around 10-15 kts from the east to northeast, although they are expected to shift southerly for a time Friday afternoon and evening. Seas 2-3 feet.
NOAA Mount Holly NJ Office: Watches - Warnings - Advisories
PA...None. NJ...None. DE...None. MD...None.