Fire Island Inlet NY to Moriches Inlet NY out 20 NM Marine Forecast
|Overnight...Se Winds 10 To 15 Kt. Seas 2 To 3 Ft.|
|Thu...E Winds 15 To 20 Kt With Gusts Up To 30 Kt. Seas 3 To 5 Ft, Building To 4 To 7 Ft In The Afternoon. Chance Of Rain In The Morning, Then Rain Likely In The Afternoon With Vsby 1 To 3 Nm.|
|Thu Night...E Winds Around 20 Kt, Becoming S After Midnight. Gusts Up To 30 Kt. Seas 5 To 8 Ft. Rain. Patchy Fog After Midnight. Vsby 1 To 3 Nm.|
|Fri...W Winds 15 To 20 Kt, Increasing To 20 To 25 Kt In The Afternoon. Seas 6 To 8 Ft. Chance Of Showers.|
|Fri Night...W Winds 25 To 30 Kt With Gusts Up To 40 Kt. Seas 6 To 8 Ft, Building To 7 To 10 Ft After Midnight.|
|Sat...W Winds 25 To 30 Kt With Gusts Up To 40 Kt. Seas 7 To 10 Ft.|
|Sat Night...Nw Winds 20 To 25 Kt With Gusts Up To 35 Kt. Seas 4 To 7 Ft.|
|Sun...W Winds 15 To 20 Kt. Seas 3 To 5 Ft.|
|Sun Night...W Winds 15 To 20 Kt. Seas 3 To 5 Ft.|
|Mon...Nw Winds 10 To 15 Kt, Diminishing To 5 To 10 Kt In The Afternoon. Seas 3 To 4 Ft.|
|Mon Night...N Winds 5 To 10 Kt. Seas 3 To 5 Ft. Chance Of Snow After Midnight With Vsby 1 To 3 Nm.|
|Area Forecast Discussion|
National Weather Service New York NY
1100pm EDT Wednesday Mar 20 2019
Synopsis: Low pressure will approach from the south through Thursday, and pass through late Thursday night, then intensify as it moves slowly northeast toward the Canadian Maritimes Friday into Saturday. High pressure building to the southwest on Sunday will give way to a cold front on Monday. Low pressure will pass to the south Tuesday into Wednesday.
Near Term - Until 6am Thursday Morning
The combination of lowering and thickening clouds and weak warm advection developing after 03Z will keep temperatures nearly steady, or rising a degree or two, overnight. Also, dew points continue to slowly rise, especially at the coastal locations, with an onshore flow. In addition, precipitation may be delayed a couple of hours across the western zones, but did not have high enough confidence at this time to lower the probabilities, as there may be some light precipitation with the developing warm advection and overrunning.
High pressure centered southeast of Nova Scotia drifts farther out to sea overnight. Meanwhile, a longwave trough to the west strengthens low pressure over the Carolinas. Moisture convergence along an inverted trough extending north brings increasing clouds and low chances of rain to mainly the southern and western sections of the area. This could be a mix of rain and snow for the interior should anything fall. The clouds and light onshore flow will keep overnight lows above normal
Short Term - 6am Thursday Morning Through Thursday Night
A shortwave within the longwave trough begins to phase with a southern stream shortwave on Thursday with the trough becoming negatively tilted Thursday night. This will guide the surface low towards us as it continues to strengthen. Rain spreads across most, if not all of the area by day's end. The low then passes through late at night with just a chance of lingering light rainfall by the end of the night. Temperatures through the event will be in the 40s.
This appears to be mainly a moderate rainfall event. The best chances of any heavier downpours appear to be during the late afternoon to evening hours. Along with a little elevated instability, this is when the area will be on the NE side of a theta- e ridge with relatively stronger moisture convergence and enhanced lift via a low level jet. Currently not anticipating any flash flooding issues, however there is at least a threat of minor urban/smaller stream flooding, more so across NE NJ based on 6 and 12-hour flash flood guidance values. Don't have at least 50% confidence of exceeding FFG values so will hold off on issuing a watch
Long Term - Friday Through Wednesday
Strengthening NW winds will be the main issue as low pressure passing through the area early Fri morning continues to phase with a digging northern stream trough on its back side and intensifies into a 980-ish mb low on its way through the Gulf of Maine and into the Canadian Maritimes. Expect sustained winds at least 25-30 mph with gusts 40-45 mph as the pressure gradient tightens late Fri night into Sat, with the strongest winds in the NYC metro area and across Long Island. Largest pressure rises likely to pass mainly well north, but could clip southern CT and eastern Long Island late day Sat and keep period of strongest winds going into the evening there.
After surface high pressure passes to the SW on Sunday, an Arctic cold front will approach and pass through on Mon, then stall to the south while low pressure rides east along it per ECMWF. The CWA looks to be close to the northern fringe of its precipitation shield, and have chance Probability of Precipitation mainly for NYC metro and Long Island Tuesday into Wed. P-type forecast starts out as snow but then becomes increasingly uncertain with time, with greater likelihood of mixed precipitation or even rain per 00Z ECMWF partial thickness forecast. Today's 12Z ECMWF is more suppressed, which would lead to little if any Quantitative Precipitation Forecast and greater likelihood of snow-- if this system follows the trend of previous low pressure systems this appears less likely to occur than the 00Z forecast.
Southeast flow across the waters was a few knots lighter than forecast and lowered wind speeds slightly into late tonight. Seas on the ocean were also running a little lower than forecast, at 1 to 1.6 feet.
Quiet conditions are expected on the waters overnight as high pressure remains offshore. Winds and waves will then increase through the day on Thursday in response to an approaching area of low pressure, likely reaching Small Craft Advisory criteria on the ocean waters by Thursday afternoon, and then on the other waters by day's end. Small Craft Advisory has therefore been issued accordingly. There may be an extended period on the non-ocean waters late Thursday night into Friday morning where winds aren't meeting advisory criteria as the low pressure center passes through the waters. With the expectation that winds ramp back up at some point on the back side of the storm, have kept the Small Craft Advisory going through Thursday night. For the ocean, seas should remain elevated late Thursday night, so should still meet advisory criteria.
As the intensifying low pulls away, gales are likely on most if not all waters Fri night into Sat, with gusts 35-40 kt. Conds improve back to Small Craft Advisory levels on all waters Sat night, with lingering minimal criteria on the ocean at least into Sunday if not farther out in time as as Arctic front drops south and low pressure approaches
No hydrologic impacts are expected through tonight. An inch to inch and a half of rain is expected Thursday into early Friday morning. This could result in some minor poor drainage flooding, more so over northeast NJ. Thereafter, no hydrologic impacts are expected through the rest of the forecast period
Tides / Coastal Flooding
Astronomical tides will be rather high over the next couple of days due to the full moon. Water levels look to fall just short of minor benchmarks during the Thursday morning high tide cycle across the south shore bays of Nassau, Queens and Brooklyn. Not enough confidence in potential flooding coverage to issue a statement for this cycle. More widespread minor flooding possible with the Thu night high tide cycle, including western Long Island Sound, with localized moderate flooding possible at some southern Nassau back bay spots
NYC NOAA Weather Radio Station KWO35 (162.55 MHz) remains off the air.
NOAA New York NY Office: Watches - Warnings - Advisories
CT...None. NY...None. NJ...None.
Small Craft Advisory from 5pm Thursday to 6am EDT Friday for ANZ330-335-338-340-345.
Small Craft Advisory from 8am Thursday to 6am EDT Friday for ANZ350-353-355.