Marine Weather and Tide Forecast for Rio Grande, NJ

NEAR TERM /THROUGH TONIGHT/
As of 640 AM, the main rain shield is gradually exiting eastern New Jersey with a band of showers moving eastward across eastern Pennsylvania and Delaware. Additional showers are farther to our west. Made some adjustments to the PoPs based on trends, and increased the winds some this morning especially closer to the coast.

Otherwise, an expansive upper-level trough will remains across much of the East, Great Lakes and adjacent Canada through tonight. Surface low pressure in the eastern Great Lakes will gradually weaken into tonight while low pressure off the Virginia coast early this morning becomes the primary low and moves to off the New Jersey coast later today and tonight. This low will then track north and northeastward through tonight.

There will be plenty of mid level energy rotating across our area within the large scale upper-level trough. An area of more concentrated rain should be pivoting to our northeast early this morning between the two surface low pressure centers. The main forcing for ascent lifts more into New England today ahead of the advancing coastal storm. However, as additional energy arrives this morning and again this afternoon from the west associated with the southeastern edge of the trough axis, shower development will continue across much of the area. Some partial clearing may try to take place later today across Delmarva especially and this would result in at least some instability. There may also be some instability developing this afternoon above the remaining shallow marine layer. While the thunderstorm risk looks to be low, some isolated thunderstorms will be possible this afternoon mostly from near and south/east of I-95. Onshore flow will continue today and this will continue to keep it chilly, although across parts of Delmarva the shallow marine layer may erode enough to get a bit more heating to occur. Overall though, temperatures today are forecast to be well below average again.

As we go through tonight, showers (possibly an isolated evening thunderstorm) into early this evening but overall the shower chances should be on the decrease. The low-level flow will turn more out of the north and northwest although it should be light and therefore the low-level moisture may be locked in for much of the night. This will tend to result in low clouds and perhaps some fog. Some additional drying may start to erode the low clouds closer to daybreak Friday. Low temperatures drop back into the mid to upper 40s for much of the region.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/
The primary surface low continues to progress further northeast away from the region. As a result, not expecting as much widespread or significant rain. However, a series of embedded short wave troughs digging southeast on the back side of the main upper level trough, will keep some chances for light rain especially Friday afternoon.

Depending on how deep the mixed layer is on Friday, there is potential for breezy conditions during the day. Latest model probabilities show up to a 50% chance for wind gusts at or above 25 mph, especially for areas near and south of Philly which are more likely to see breaks in the clouds, and thus more likely to see a deeper mixed layer.

LONG TERM /SUNDAY THROUGH WEDNESDAY/
With the upper level low and embedded short wave troughs finally further away from the region by Sunday, a surface high briefly builds in over the region bringing dry conditions.

The next feature to watch is a low pressure system organizing and developing to the south which will lift north and east. There is uncertainty on the exact track of this low and especially with the timing of this low. Some guidance shows potential for rain in our region as early as Monday/Memorial Day, while other guidance depicts it slower, with rain not entering our region until late Tuesday.
Additionally, depending on the exact track and how quickly the high departs, there could be a tight north- south gradient in the rain.

AVIATION /12Z THURSDAY THROUGH MONDAY/
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas.

Today...IFR ceilings lifting to MVFR at times, and some locations can improve to a VFR ceiling for a time. MVFR or IFR visibilities at times due to showers. A few isolated thunderstorms possible this afternoon, mainly near and south/east of KPHL. Northeast winds around 10 knots with some local gusts to 20 knots becoming north-northwest closer to early evening. Low confidence with the details/timing.

Tonight...IFR ceilings should improve to MVFR, then possibly VFR toward daybreak Friday. Some showers around especially in the evening, with an isolated thunderstorm possible. North winds around 5 knots becoming northwest to west-northwest, to even locally light and variable. Low confidence.

Outlook...

Friday through Saturday...Brief MVFR conditions possible in some showers.

Sunday and Monday...Prevailing VFR.

MARINE
A Small Craft Advisory remains in effect for the ocean waters through tonight. The Small Craft Advisory for Delaware Bay was cancelled earlier as conditions are anticipated to remain below criteria. The strong easterly winds will ease from south to north today and tonight with this taking the longest across the northern New Jersey Atlantic coastal waters. Elevated seas will also remain.

Outlook...

Friday...elevated seas and even some winds near 25 kt may linger for part of the day on Friday, but confidence is too low to extend the SCA at this time.

Saturday through Monday...Winds and seas should stay below SCA criteria.

Rip Currents...

Today...For Monmouth and Ocean counties, northeasterly winds 15-25 mph with a 7-9 second period and breaking waves of 3-5 feet. A HIGH risk for the development of dangerous rip currents is in place. For Atlantic, Cape May and Delaware beaches, northeast to north winds 15-20 mph with a 7-9 second period and breaking waves of 2-4 feet. A MODERATE risk for the development of dangerous rip currents is in place.

Friday...West winds 10-20 mph with an 8-10 second period and breaking waves of 2-4 feet. A MODERATE risk for the development of dangerous rip currents is in place.

For specific beach forecasts, visit weather.gov/beach/phi

TIDES/COASTAL FLOODING
Prolonged onshore, easterly flow will continue to result in elevated water levels. Even though astronomical tides aren't particularly high currently, this extra surge will be enough to result in minor tidal flooding with the afternoon/evening high tide today. At this point the primary areas of concern are along the immediate coast and nearest back bays from south of the Manasquan inlet to Fenwick Island and the shores of the Delaware Bay in Kent and Sussex Counties in Delaware.

For other areas, tide levels could get close to minor flood thresholds, but based on the latest tide levels, expect them to stay below levels at which we see impacts.

Of note, guidance has been consistently too high with tide levels during this event.

Once we get to Friday, flow shifts to off shore and thus the risk for tidal flooding on subsequent high tide cycles decreases.

PHI WATCHES/WARNINGS/ADVISORIES
PA...None.
NJ...Coastal Flood Advisory from 3 PM this afternoon to 9 PM EDT this evening for NJZ020-022>027.
High Risk for Rip Currents through this evening for NJZ014-026.
DE...Coastal Flood Advisory from 3 PM this afternoon to 9 PM EDT this evening for DEZ002>004.
MD...None.
MARINE...Small Craft Advisory until 6 AM EDT Friday for ANZ450>455.