Manasquan Inlet to Little Egg Inlet NJ out 20 NM Marine Forecast
|Today...Nw Winds 5 To 10 Kt, Becoming S This Afternoon. Seas 3 To 4 Ft. Swell Mainly From The S With A Dominant Period Of 7 Seconds.|
|Tonight...Sw Winds 5 To 10 Kt, Becoming N Late. Seas Around 3 Ft. Swell Mainly From The Se With A Dominant Period Of 7 Seconds.|
|Wed...E Winds 5 To 10 Kt. Seas Around 3 Ft. Swell Mainly From The Se With A Dominant Period Of 7 Seconds.|
|Wed Night...Se Winds 10 To 15 Kt. Seas Around 3 Ft. Swell Mainly From The Se With A Dominant Period Of 6 Seconds, Becoming Mainly From The E With A Dominant Period Of 4 Seconds After Midnight.|
|Thu...Se Winds Around 10 Kt. Seas Around 3 Ft.|
|Thu Night...S Winds Around 10 Kt. Seas Around 3 Ft.|
|Fri...S Winds 10 To 15 Kt. Seas Around 3 Ft. A Chance Of Showers In The Morning, Then A Chance Of Tstms In The Afternoon.|
|Fri Night...Sw Winds 10 To 15 Kt. Seas Around 3 Ft. A Chance Of Tstms.|
|Sat...S Winds 5 To 10 Kt. Seas Around 3 Ft. A Chance Of Tstms In The Morning.|
|Sat Night...Sw Winds 5 To 10 Kt. Seas Around 3 Ft. Winds And Seas Higher In And Near Tstms.|
Area Forecast Discussion|
National Weather Service Mount Holly NJ
621am EDT Tuesday July 14 2020
High pressure will build into the eastern U.S. through midweek. A backdoor cold front will move south into the area late tonight and Wednesday before lifting northward as a warm front on Thursday and Friday. A weak cold front will approach the East Coast near the end of the week into the weekend, but high pressure in the Southeast will likely aid in its stalling and eventual dissipation.
.NEAR TERM Through Tonight
615 am update: No changes to the forecast required.
A potent midlevel trough is moving into New England at this time and will continue its eastward movement today. The trough axis is expected to be offshore by early afternoon, with large- scale descent likely encompassing the region thereafter. Models (convection-allowing and coarser deterministic) are skittish in producing convection near the vorticity maximum in our CWA today, and given the unfavorable position/timing of the trough, I went with a dry forecast today. Having said that, a stray shower/storm is possible, especially near/north of I-80, but chances are simply too low at a given location to justify Probability of Precipitation at this time.
At the surface, high pressure will move slowly through the Midwest today, with a cold front attendant to the trough slowly migrating farther and farther offshore. In between, weak cold/dry advection should occur, with the result being mostly sunny skies and fairly comfortable humidity levels. Given the degree of insolation and slight downsloping component expected, highs will likely be near to slightly above seasonal averages.
The surface high will progress into the Appalachians by 12z Wednesday, with a quiet night expected in our area as winds decouple and dew points remain seasonably comfortable. Lows are expected to be near or slightly above seasonal averages.
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... This period will continue to be dominated by surface high pressure, as it migrates eastward through the Northeast. Notably, however, this will change wind directions to northeasterly or easterly early in the day. Such onshore flow often results in cooler temperatures, and notably, the MET guidance is trending a few degrees downward for highs. However, the other guidance is not really sold on this, owing to a few factors. First, midlevel ridging will strengthen across the area, and these height rises may translate into warmer temperatures than otherwise would be expected. The second factor would be the lack of cloud cover. With the climatological peak of the year in terms of warmth (and near peak regarding insolation), temperatures may warm readily despite cooler backward trajectories. Third, it may take some time for the cold advection to take hold across the area (i.e., more noticeable on Thursday, especially as cloud cover increases Wednesday night).
Expecting the most noticeable cooling to be near the coast and in the far northeastern CWA, where onset of onshore flow will be soonest. Highs near the coast may not reach 80, while the urban corridor may still approach 90. However, the forecast is of below-average confidence, as the NAM-based guidance typically is on to something in these regimes. Lows Wednesday night will likely be in the 60s across the CWA. With midlevel ridging in place, expecting a dry 24-hour period for the region.
Long Term - Thursday Through Monday
Several concerns for the medium-range period, including an approaching front at the end of the week, its eventual stalling and dissipation this weekend, and the return of heat/humidity/diurnal convection next week.
A midlevel vort max will approach the Northeast on Thursday, with large-scale ascent downstream aiding in the development of convection along and in advance of the attendant front moving into the central Appalachians during the afternoon. Deterministic models are beginning to converge on a solution here, with most developing fairly widespread coverage of storms in the higher terrain to the west of the area. Usually, there is spillover into the western CWA in these setups (generally underestimated by coarser guidance), but areas east of the urban corridor may remain dry given lingering effects of midlevel ridging. Fine-tuned Probability of Precipitation considerably for Thursday, mainly keeping slight-chance to chance categories confined to areas west of the Fall Line.
Models simulate convection spreading eastward into the area during the overnight hours, which seems pretty reasonable given the strength of the approaching trough and associated large- scale ascent. Increased Probability of Precipitation eastward for this period. However, the front only makes slow progress eastward given the strength of ridging south and east of the trough, so expecting more convection on Friday. Given the slow nature of the front and anomalous moisture expected to be in place by this time (PWs near 2 inches, e.g.), think locally heavy rainfall may be a concern with this system. Additionally, unperturbed preconvective CAPE on Friday will likely exceed 1000-1500 J/kg (muted perhaps by lingering capping from the antecedent ridge) in an environment of 20-30 kt deep-layer shear. Will need to watch this period both for local severe/hydro hazards.
The front will only make slow progress southeastward this weekend, and deterministic guidance at least suggests the possibility of convection developing on Saturday, especially in southern portions of the area, closer to the consensus projected location of the gradually dissipating boundary. However, given the expected demise of the front, cannot rule out convection entirely anywhere, though certainly not expecting a washout. With the dying front, south/southwest winds may become reestablished, allowing for increased heat/humidity.
Midlevel ridging should increase late in the weekend, with the development of a prefrontal trough possible by Sunday afternoon. Cannot rule out isolated convection with this setup, mainly in the western CWA, but expecting conditions to be dry for most. With south/southwest flow continuing and midlevel ridging increasing, expect the heat machine to begin in earnest. Highs 5-10 degrees above seasonal averages are expected, with dew points high enough by this point to result in heat indices approaching heat-advisory levels.
The trend only worsens on Monday, as warm/moist advection continue in advance of an approaching perturbation. Consensus forecasts are for highs in the mid 90s in the urban corridor by this point, with dew points in the 70s. Should this occur, heat advisories would likely be required for portions of the area. However, the aforementioned perturbation may provide for increased chances of convection, with both the 00z GFS/ECMWF suggesting this potential Monday afternoon/evening. Given the stagnant pattern (zonal flow to our north and broad ridging to our south), hot/humid conditions with near-daily rounds of convection seem probable well into next week.
Sub-advisory winds/seas are expected through tonight. Winds will likely become southerly for a time today before fairly quickly becoming northwesterly this evening. Thereafter, directions will gradually become north or even northeast by daybreak Wednesday. Speeds will generally be 5 to 15 kt. Seas around 3 feet should be expected.
Outlook... Wednesday through Thursday...Sub-advisory winds/seas and fair weather expected.
Thursday night through Saturday...Sub-advisory winds/seas expected. A chance of storms, especially on Friday and Friday night, with locally higher waves and strong wind gusts in their proximity.
Rip Currents... Breaking waves are forecast to be 2 feet or less with a medium- period southeast swell along the coasts of Delaware and New Jersey today. A light and variable wind in the morning is forecast to settle into the south around 5 to 15 mph in the afternoon. The risk for the development of dangerous rip currents is expected to be low.
The wave and swell conditions are anticipated to remain nearly the same for Wednesday. However, the wind is forecast to become easterly around 10 to 15 mph. The low risk of rip currents is expected to continue.
The NOAA Weather Radio All Hazards broadcast from Hibernia Park, PA (WNG704) remains off the air until further notice due to damage to the antenna during the June 3 derecho.
NOAA Mount Holly NJ Office: Watches - Warnings - Advisories
PA...None. NJ...None. DE...None. MD...None. MARINE...None.