Delaware Bay south of East Point NJ to Slaughter Beach DE Marine Forecast
|Today...Sw Winds 5 To 10 Kt, Becoming N This Afternoon. Waves 2 Ft Or Less. A Chance Of Rain Early This Afternoon. A Chance Of Rain Or Snow Late.|
|Tonight...Ne Winds 10 To 15 Kt With Gusts Up To 20 Kt, Becoming N 25 To 30 Kt With Gusts Up To 35 Kt. Waves 2 Ft Or Less, Then 3 To 4 Ft After Midnight. A Chance Of Rain Early In The Evening. Snow. Vsby 1 To 3 Nm, Decreasing To 1 Nm Or Less After Midnight.|
|Sat...Nw Winds 25 To 30 Kt With Gusts Up To 40 Kt. Waves 3 To 5 Ft. Snow Until Late Afternoon, Then Snow Likely Late. Vsby 1 Nm Or Less, Increasing To 1 To 3 Nm Late.|
|Sat Night...Nw Winds 25 To 30 Kt With Gusts Up To 40 Kt, Diminishing To 20 To 25 Kt With Gusts Up To 30 Kt Late. Waves 3 To 5 Ft. A Chance Of Snow Early In The Evening. Light Freezing Spray Likely. Vsby 1 To 3 Nm Early In The Evening.|
|Sun...Nw Winds 15 To 20 Kt With Gusts Up To 30 Kt, Becoming W 10 To 15 Kt With Gusts Up To 20 Kt In The Afternoon. Waves 3 To 4 Ft. Light Freezing Spray Likely.|
|Sun Night...Sw Winds 5 To 10 Kt. Waves 2 Ft Or Less.|
|Mon...N Winds Around 5 Kt, Becoming Ne In The Afternoon. Waves 2 Ft Or Less.|
|Mon Night...Ne Winds 5 To 10 Kt. Waves 2 Ft Or Less.|
|Tue...Ne Winds 5 To 10 Kt. Waves 2 Ft Or Less.|
|Tue Night...E Winds 5 To 10 Kt. Waves 2 Ft Or Less.|
| Area Forecast Discussion|
National Weather Service Mount Holly NJ
332am EST Fri Jan 28 2022
A strong coastal storm developing off the Southeast coast will lift just off the east coast through Saturday night. High pressure returns for the end of the weekend and early next week. Another low pressure system may approach our region late next week.
Near Term - Until 6pm This Evening
A cold front extended across the eastern Great Lakes region early this morning. The boundary will sink to the southeast and it is forecast to reach the Poconos early this afternoon. The front will continue to work its way through the rest of eastern Pennsylvania and New Jersey, and into eastern Maryland and Delaware late in the day. It should eventually begin to be absorbed into the developing circulation around the strengthening low moving up the East Coast.
Some light precipitation was drifting northeastward out of the Ohio River Valley early this morning, in advance of the cold front. It is separate from the significant precipitation event that will impact our region tonight into Saturday. This initial shot of light precipitation should spread into eastern Pennsylvania and northern New Jersey this morning, before expanding southeastward into eastern Maryland, Delaware and southern New Jersey this afternoon.
The expected temperature profiles suggest areas of light snow for much of eastern Pennsylvania and northern New Jersey with a light dusting possible during the daylight hours. Boundary layer temperatures should warm enough in much of eastern Maryland, Delaware and southern New Jersey for this afternoon to cause much of this initial shot of precipitation to be areas of light rain at those locations.
Even though we are anticipating a cloudy sky for today, the general southwest flow ahead of the approaching boundary will likely allow temperatures to rise into the upper 30s and lower 40s in eastern Maryland, Delaware and southern New Jersey. Temperatures are forecast to rise into the lower and middle 30s in much of southeastern Pennsylvania and northern New Jersey, with readings not getting above the 20s in the Poconos.
Short Term - 6pm This Evening Through Saturday Night
...Major winter storm expected to affect much of the region Friday night and Saturday... Bottom Line Up Front: Rest of winter storm watch upgraded to winter storm warning. Warning expanded to include Hunterdon and Morris Counties in NJ. Coastal counties of NJ and the coastal strip of Sussex County DE upgraded to a blizzard warning. Winter weather advisory issued in a narrow corridor to the west of the winter storm warning (Chester County PA to Sussex County NJ). Wind chill advisory issued for the southern Poconos for Saturday night.
And if you followed all of that... From a forecasting standpoint, the good news is that models are steadily converging on the overall evolution of the winter storm anticipated to affect much of our area during the short-term period. Models continue to exhibit two important trends that are becoming more favorable for significant snowfall in the eastern half or so of the CWA. (1) A southern-stream vort max is trending faster in its migration eastward from the southern Plains on Friday. (2) A northern-stream digging vort max is trending slightly slower and stronger/deeper. The NAM, GFS, ECMWF, and CMC are all trending in this direction (to varying degrees and with somewhat varying consistency) with both phenomena, as well as respective ensembles. This has led to a general westward shift in the surface low just off the East Coast attendant to the more quickly phasing large-scale trough in the eastern U.S. Friday night and Saturday (as well as a noticeably deeper and more negatively-tilted trough). Consensus snowfall totals are beginning to increase in areas to the south and east of the Fall Line, and confidence continues to increase that warning-level snow will occur in much if not most of the winter storm watch area. As a result, have upgraded remaining portions of the watch to a warning on this shift.
The forecasting challenges tonight have been associated with the margins. For example, how much will snowfall totals decrease on the northwest periphery of the precipitation shield? Well, guidance suggests that this cutoff will be quite sharp, which is unsurprising given the strong push of cold/dry air on the northwest side of the synoptic system. There will likely be a very narrow corridor (read: around or less than 30 miles) where totals go from warning levels to sub-advisory levels, and confidence remains considerably lower on where this corridor will set up. Given the westward shift with the guidance in general the past 24 hours, this looks to be roughly near or more likely a little southeast of the Fall Line (at this time anyway; we will see how this forecast shifts the next couple of cycles). As a result, the adjoining winter weather advisory is for a narrow geographic region: Chester County PA to Sussex County NJ. Forecast snow totals drop off quickly to sub-advisory levels for the Lehigh Valley, southern Poconos, and Berks County; therefore, no advisory was issued for these areas at this time.
Another margin: Will portions of the region reach blizzard criteria? Short-range ensemble guidance strongly suggests the near-coast will feature several hours with winds above 30 mph and visibilities near or below a quarter mile. It will be increasingly tough to do farther inland, but think this threat spills into the eastern portions of the inland coastal zones of New Jersey. As a result, have upgraded the winter storm warning in these areas to a blizzard warning. Notably, inland Sussex County in Delaware remains in a winter storm warning, owing to increased uncertainty that these conditions will spill into much more than the immediate Atlantic coast. Blizzard conditions are very tough to meet (reaching the above conditions for 3+ hours), but even if they fall just short in the blizzard-warning area, conditions are very likely to be quite hazardous, with nearly- impossible travel expected.
The next margin discussed here is the winds themselves. Speeds exceeding 25-30 mph are pretty likely for much of the day on Saturday, with only a slow drop-off expected Saturday night. Gusts of 40+ mph are quite possible, especially in the Poconos and near the coast. Winter products will cover the winds along the coast, but the Poconos will not reach snow criteria. However, with temperatures falling in the cold-advection regime in the wake of the coastal low, very low wind chills are expected Saturday afternoon through Saturday night. Confidence is high that advisory conditions will be reached in the southern Poconos. Have gone ahead and hoisted a wind chill advisory Saturday evening through Sunday morning.
The final margin is associated with Quantitative Precipitation Forecast and snow ratios. Quantitative Precipitation Forecast is trending a little higher across the region, as to be expected with the westward shift in model consensus. Snow ratios will be very high (much greater than 10:1), thanks to the antecedent cold thermodynamic profiles; however, guidance looks a little too bullish in general with these values, based on past experience. It will be interesting how these two forecast fields play out over the course of the event, as this will have pretty significant implications on snow totals near the coast (where the highest Quantitative Precipitation Forecast exists) and near the northwest fringe of the snow shield (where the highest snow ratios exist, and where uncertainty in Quantitative Precipitation Forecast is highest). My current feeling is that totals on the coast may be a little on the high side given a potential positive snow-ratio forecast bias, but may be a little on the low side in the northwest CWA (where snow ratios may be higher, and where forecasts have trended west with Quantitative Precipitation Forecast in recent model suites).
Bottom line here: even though confidence in the overall evolution of the storm is increasing, there are still very challenging aspects to the winter storm that may have significant implications on the overall impacts of the system location to location. Continue to monitor the latest forecasts, as substantial changes may still occur.
Long Term - Sunday Through Thursday
Overview: Tranquil conditions are expected for much of the long term as a surface high slides over the region at the beginning of the week. By mid week, a low pressure system lifting northeast out of the lower Mississippi Valley.
Sunday...pressure gradient should decrease quickly Sunday Morning, and should see a subsequent decrease in wind speeds as well. None the less, low level flow will generally stay northwesterly and westerly through the day, meaning there will be little opportunity for warm air advection on Sunday. As a result, temperatures across the region are likely to stay below freezing Sunday and Sunday night. However, mostly sunny conditions early in the day may help somewhat with snow melt. For Sunday night, have stayed close to a blend of guidance for low temperatures. Increasing clouds (in response to a weak mid level short wave trough passing over the region) will act against efficient radiational cooling, though expansive snow field could mean that the guidance is too warm.
Monday and Tuesday...Surface high slides over the region Monday into Tuesday. Another weak mid level short wave trough may cross the region late Monday into Monday night, but will little opportunity for moisture advection ahead of it, we aren't expecting any precipitation with it. We'll start to see a modest warming trend on Monday, but a much more significant warming trend going into Tuesday as a mid level ridge briefly builds over the region. By Tuesday, highs should be mostly in the 40s (with the exception of the southern Poconos and NW NJ, which may stay in the 30s).
Wednesday And Thursday
From Wednesday into Thursday, will be watching a low which now looks like it will develop over the lower Mississippi Valley lift northeast into western New England. This is a slightly further east track than what much of the deterministic models were depicting yesterday, so will be watching closely to see if this trend continues. For now though, this track would mean the warming trend would continue especially Wednesday night into Thursday when the warm front associated with this low would lift through our region. With this track, our region would be within the warm sector during most of the period when we were expecting precipitation, so it would likely be mostly, if not all, rain. Two things that could change this are a northern stream low crossing southern Canada Tuesday into Wednesday and the trend east with the main low. If the northern stream low digs further southeast, or if the center of the main low passes east of our region, we could see dramatically different outcomes from the current forecast. That being said, there is surprisingly good agreement between most of the deterministic models on the current solution, so will stay close to a blend of guidance in this period for now.
A southwest wind near 10 knots this morning is forecast to become northwest to north for this afternoon as a cold front pushes southeast toward the coastal waters of New Jersey and Delaware. Wave heigheights on our ocean waters should be around 2 feet, with waves on Delaware Bay at 2 feet or less.
Outlook... Friday night through Saturday night...Rapid deterioration in conditions likely Friday night, as northeast winds quickly increase during the evening. At least advisory conditions expected by late evening, with gales developing on all waters overnight; the previously issued gale warning remains in effect.
Winds will become north to northwest on Saturday, with gusts exceeding 40-45 kt likely. Storm conditions appear increasingly probable off the northern and central NJ coast. Have issued a storm warning off Monmouth/Ocean Counties for Saturday, while the rest of the waters retain gale-warning status. Winds should peak during the afternoon and early evening, with a gradual diminishing trend late Saturday night. Gales will likely continue through the night.
Additionally, heavy snow is likely late Friday night through at least Saturday afternoon. Visibility restrictions are likely. Finally, with increasingly cold air and strong northwest winds on Saturday night, freezing spray is likely to develop, primarily close to the coast. A freezing spray advisory has been issued for all waters Saturday night.
Sunday through Tuesday...once winds and seas drop below 25 kt and 5 ft later in the day on Sunday, winds and seas should stay below SCA (Small Craft Advisory) criteria through Tuesday.
Tides / Coastal Flooding
The potential for minor tidal flooding along much of the New Jersey and Delaware coastline on Saturday morning has increased based on the latest track of the forecast northeaster.
A north northeast wind is expected to develop this evening, with wind speeds increasing to 25 to 35 MPH late tonight. Ekman transport will push water toward the coast. The period of time with an onshore push leading up to Saturday morning's high tide will be somewhat limited (less than 12 hours). However, it should be a long enough duration to produce the surge of +1.2 to +1.4 feet needed to begin causing minor flooding along the coasts of Delaware and New Jersey. The ETSS guidance has been coming into better agreement with the NYHOPS forecasts as the GFS model has been trending westward with the track of the low.
Based on the latest guidance, it appears as though widespread minor tidal flooding is likely in our coastal counties from Ocean in New Jersey, southward to Sussex in Delaware. Those counties have been placed under a Coastal Flood Advisory. Only spotty minor flooding is anticipated for Monmouth County in New Jersey, and for Kent County in Delaware. Based on the expected wind direction and duration of the onshore flow, no flooding is forecast along Raritan Bay, along the New Jersey side of Delaware Bay, along the tidal Delaware River or on the upper eastern shore of Chesapeake Bay.
Even as the wind backs to the northwest for Saturday evening, water levels along the coast should remain elevated. Saturday evening's high tide is the lower of the two daily high tides, so no flooding is expected at that time.
The guidance continues to hinting at a lingering round of spotty minor flooding with Sunday morning's high tide before the water begins to drain away from the coast.
NOAA Mount Holly NJ Office: Watches - Warnings - Advisories
PA...Winter Storm Warning from 7pm this evening to 7pm EST Saturday for PAZ070-071-104-106. Winter Weather Advisory from 7pm this evening to 3pm EST Saturday for PAZ101>103-105. Wind Chill Advisory from 6pm Saturday to 10am EST Sunday for PAZ054-055. NJ...Winter Storm Warning from 7pm this evening to 7pm EST Saturday for NJZ008>010-012-015>019-021. Coastal Flood Advisory from 3am to 9am EST Saturday for NJZ020-022>027. Blizzard Warning from 7pm this evening to 7pm EST Saturday for NJZ013-014-020-022>027. Winter Weather Advisory from 7pm this evening to 3pm EST Saturday for NJZ001-007. DE...Winter Storm Warning from 7pm this evening to 7pm EST Saturday for DEZ003. Coastal Flood Advisory from 3am to 9am EST Saturday for DEZ003-004. Blizzard Warning from 7pm this evening to 7pm EST Saturday for DEZ004. Winter Storm Warning from 7pm this evening to 3pm EST Saturday for DEZ001-002. MD...Winter Storm Warning from 7pm this evening to 3pm EST Saturday for MDZ012-015-019-020.
Freezing Spray Advisory from 6pm Saturday to noon EST Sunday for ANZ430-431-450>455. Gale Warning from 11pm this evening to 6am EST Sunday for ANZ430-431-452>455. Storm Warning from 6am to 6pm EST Saturday for ANZ450-451. Gale Warning from 11pm this evening to 6am EST Saturday for ANZ450-451.