Another Big Rainstorm This Weekend (12/17-18)...

[RU848789]

Well, there's not much winter to talk about, so figured I'd give a heads up on a nearly identical forecast for this Sunday into Monday as we had this past weekend, after another very nice Friday/Saturday. Looks like things start to go downhill Sunday afternoon with the worst of it being Sunday night through maybe the Monday morning commute with the mid-range models showing 1.5-3" of rain for the region and wind gusts up to 50+ mph, especially along the DE/NJ/LI coasts. This sounds similar to the 1.5-3.5" of rain most of us got last weekend, but one big difference is that we now have saturated soils from those heavy rains, so the chances of urban and stream/river flooding will be greater (and could be significant).

This being a true nor'easter (last week's wasn't quite), which is actually a Miller A storm, originating in the Gulf of Mexico and then moving towards the Atlantic coast and coming up the coast, soaking everywhere from FL to Maine, the chances of the higher winds verifying are pretty good, plus there's more chance of some minor coastal flooding with this storm. Unfortunately, for snow lovers, with a track inland of the coast, there is zero chance of any frozen precip through Monday morning (not even much chance for the NY/New England ski resorts), although there is the chance for some minor snowfall NW of 95 early on Tuesday with an approaching clipper-style system.

https://forecast.weather.gov/produc...&format=CI&version=1&glossary=1&highlight=off

FYI, there doesn't look like much chance of snow the next two weeks, but there are signs of a possible pattern change to a colder regime in late December, which would increase the likelihood of snow chances. Many analog analysts who compare winter seasons are likening this winter to 2015-2016, which was also an El Nino winter and had very little NE US snowfall through mid-January, but we then had the Jan-2016 blizzard that set the all-time NYC snowfall record of 27.5" (got ~22" in Metuchen) and slightly above average winter snowfall. No idea what's going to happen this year, as nobody seems to have figured out a way to predict seasonal snowfall accurately (unlike seasonal tropical activity forecasts, which have some accuracy). And way too early to predict the weather for the Pinstripe Bowl.

https://www.nytimes.com/2023/12/14/us/rain-storm-forecast-snow.html

 

[93RUDoc]

Much Appreciated

 

[rurichdog]

Saturated soils after 4 days of sunny skies & dry air? I feel like that term is being used very loosely.

 

[Knight Shift]

Well, there's not much winter to talk about, so figured I'd give a heads up on a nearly identical forecast for this Sunday into Monday as we had this past weekend, after another very nice Friday/Saturday. Looks like things start to go downhill Sunday afternoon with the worst of it being Sunday night through maybe the Monday morning commute with the mid-range models showing 1.5-3" of rain for the region and wind gusts up to 50+ mph, especially along the DE/NJ/LI coasts. This sounds similar to the 1.5-3.5" of rain most of us got last weekend, but one big difference is that we now have saturated soils from those heavy rains, so the chances of urban and stream/river flooding will be greater (and could be significant).

This being a true nor'easter (last week's wasn't quite), which is actually a Miller A storm, originating in the Gulf of Mexico and then moving towards the Atlantic coast and coming up the coast, soaking everywhere from FL to Maine, the chances of the higher winds verifying are pretty good, plus there's more chance of some minor coastal flooding with this storm. Unfortunately, for snow lovers, with a track inland of the coast, there is zero chance of any frozen precip through Monday morning (not even much chance for the NY/New England ski resorts), although there is the chance for some minor snowfall NW of 95 early on Tuesday with an approaching clipper-style system.

https://forecast.weather.gov/produc...&format=CI&version=1&glossary=1&highlight=off

FYI, there doesn't look like much chance of snow the next two weeks, but there are signs of a possible pattern change to a colder regime in late December, which would increase the likelihood of snow chances. Many analog analysts who compare winter seasons are likening this winter to 2015-2016, which was also an El Nino winter and had very little NE US snowfall through mid-January, but we then had the Jan-2016 blizzard that set the all-time NYC snowfall record of 27.5" (got ~22" in Metuchen) and slightly above average winter snowfall. No idea what's going to happen this year, as nobody seems to have figured out a way to predict seasonal snowfall accurately (unlike seasonal tropical activity forecasts, which have some accuracy). And way too early to predict the weather for the Pinstripe Bowl.

https://www.nytimes.com/2023/12/14/us/rain-storm-forecast-snow.html

You got my hopes up for the last one. I have reasons for wanting a good storm and felt let down with the last one.

 

[knightfan7]

Should be some minor with a chance of moderate tidal flooding along the coast Sun night and Mon morning.

 

[RedTeam1994]

Saturated soils after 4 days of sunny skies & dry air? I feel like that term is being used very loosely.

yeah, that made me wonder too. "saturated soils"...what?

 

[zappaa]

I’m sure it will produce enough rain and continue long enough to activate the 2 leaks I’m dealing with at home….ugh

 

[jaydogsmooth1]

Dave Curran from News 12 saying things lining up for a cold end of January - early February, and that could lead to some significant snowfall. Still too early to tell, but something to keep an eye on

 

[RuRats27]

I was supposed to come up to NYC on Sunday and Monday to take the family to see the tree and sites around Manhattan. Rethinking that now with this forecast. Am I right in that it looks like most of Sunday and Monday are going to be a total rain out with high winds to boot?

 

[knightfan7]

Keep checking the NWS site. No commercial network hysteria.

 

[RU848789]

I was supposed to come up to NYC on Sunday and Monday to take the family to see the tree and sites around Manhattan. Rethinking that now with this forecast. Am I right in that it looks like most of Sunday and Monday are going to be a total rain out with high winds to boot?

Yes, complete washout from late afternoon Sunday through about late morning on Monday for NYC and most locations in our area, with 1.5-2.5" forecast and some areas likely getting 3" or more; the graphic below is for Edison, bu NYC will be similar. With mostly saturated ground conditions, urban/stream flooding is more likely than last weekend and there will also likely be some minor coastal flooding (maybe moderate for LI). Winds pick up late Sunday evening with gusts to 30-40 mph for most and maybe up to 50 mph at the coast, although no wind advisories yet. Rains will be lighter before sunset on Sunday and after about noon on Monday. No snow for anyone, even in northern New England.

https://www.weather.gov/phi/

 

[RU848789]

You got my hopes up for the last one. I have reasons for wanting a good storm and felt let down with the last one.

Your forecast for rainfall verified perfectly and your forecast for winds was only a bit too high. Not sure what you were expecting.

 

[RU848789]

Saturated soils after 4 days of sunny skies & dry air? I feel like that term is being used very loosely.

Yes, saturated soils remain. With cool temps, even with drier air and some sunshine, evaporation only really occurs from the top several inches of soil, leaving most of the soil column saturated, after heavy rains like last weekend. See the AFD below from the NWS; the soil moisture maps also show mostly saturated soils.

Area Forecast Discussion
National Weather Service Mount Holly NJ
827 PM EST Fri Dec 15 2023

SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...

Overall, model consensus remains for a storm up the East Coast
though slightly further inland than the previous set of
guidance. In any case, the deepening low pressure system
arrives from the south late Sunday then shifts to our north on
Monday. This still looks to bring impacts to the region, which
includes the Monday morning commute.

As the potent upper-level trough arrives, ample deep-layer forcing
for ascent coupled with robust low-level warm air advection occurs.
An intense low-level jet on the order of 50-75 knots (at 925 mb) is
forecast to lift northward in tandem with the surface low. This
impressive wind field will drive robust low-level warm air and
moisture advections. It is within this zone where the heaviest rain
will probably fall, as precipitable water values rapidly increase to
about 1 to 1.5 inches across the region. The high precipitable
water and ample lift will result in a period of heavy rain,
which as of now looks to occur Sunday night into Monday morning.
Rainfall totals look to be at least 1.5 to 2 inches widespread across
the area, even with accounting for the slightly more inland
track with the latest guidance and the potential for any faster
northward movement of the storm. The latest forecast maintains a
maxima of around 3 inches though that has notably shifted to the
northwestern half of the region with the shift in track. With
the potential development of mesoscale banding along the fronts,
localized totals above 3 inches remain possible. In any case,
given the rainfall will be onto a saturated ground, there is a
flooding risk and this will be enhanced especially if much of
the heavier rain falls in a shorter period of time. We will
need to watch some of our creeks and streams, especially the
quicker responding ones. As a result of all of the above, a
Flood Watch has been issued for the Sunday night and Monday
periods.

In addition, a robust low-level wind field will pile water into the
coast, although the robust warm air advection over and off the
cooler ocean waters tends to create a more stable boundary layer.
Despite this, the guidance show impressive 3 and 6 hour pressure
falls associated with this storm and this can compensate for any
stable marine influence. As a result, wind advisory gusts (40-50
mph) are possible mainly closer to the coast. The strongest winds
should lower some farther inland, although the higher terrain should
see some higher winds given the robust wind field within about 2500
feet above the ground.

The consensus of the guidance brings the surface low across our
area, generally in SE PA, a bit further west than the previous
set of guidance. As stated above, this track would tend to shift
the area of maximum rainfall further west in our region but
would still maintain the strong winds. The specific outcome
will ultimately depend on the exact track of the surface low and
its intensity. A surge of warmer air will work its way
northward in advance of the surface low, and this should result
in mild temperatures Sunday with temperatures possibly rising
some more Sunday night.

As the surface low shifts northward across our area Monday morning,
it should then be undergoing an occlusion. This will quickly end the
rain from south to north Monday, although the morning commute could
be impacted with some heavier rain still falling along with possibly
some street flooding. Winds will turn sharply from the west and
northwest in the wake of the storm Monday with temperatures and dew
points on the fall as cold dry air advection occurs under a gusty
wind. Temperatures should peak Monday morning then fall at least
some during the day.

 

[Knight Shift]

Your forecast for rainfall verified perfectly and your forecast for winds was only a bit too high. Not sure what you were expecting.

more wind with bigger gusts.

 

[RU848789]

more wind with bigger gusts.

You're likely to get your wish, as this storm is likely going to be more powerful than last weekend's, especially with regard to winds and will likely be one of the most powerful nor'easters of the past several years. Wind advisories are up for the NJ coast for gusts up to 50 mph and for winds up to 60 mph from NYC eastward through LI. It's also worth noting that some models are showing up to 60 mph winds for the NJ coast and even up to 45-50 mph inland (and up to 70 mph for LI).

Similarly, coastal flood advisories are up for minor flooding along the NJ Shore and for moderate flooding for NENJ (Hudson/Essex/Union)/NYC/LI and CT; again, moderate flooding is possible for the NJ coast if the more aggressive models verify. And let's not forget the rains, as 1.5-3.0" are still forecast by the NWS for the region (2-4" forecast by Channel 7, but the way), but some models are showing up to 4-5" in much of the area with 2-4" falling from about midnight to sunrise Monday; the former would lead to widespread urban/stream flooding, while the latter could lead to moderate and maybe even major flooding.

Good thread on AmericanWx on the storm and DT/WxRisk has a nice write-up on his FB page...

https://www.americanwx.com/bb/topic...-snow-interior-elevations-tue-morning/page/6/

https://www.facebook.com/WxRisk/

 

[RU848789]

Some ridiculous rainfall amounts (6-10") in parts of the SE US from FL to VA, so far, and the NWS has upped the rainfall forecast for our area just a bit, to a widespread 2-4" (with the higher amounts inland and the lower amounts towards the coast) leading to fairly widespread minor to moderate stream/river flooding, as per the graphics below.

Wind forecasts have been increased a touch, also, as per the graphic below, with gusts to 50 mph at the NJ coast and even higher for NYC/LI and this is part of why widespread minor coastal flooding is predicted for much of the NJ/DE coasts and moderate coastal flooding is predicted for interior NENJ/NYC locations from the long fetch of SE winds piling water up the Hudson River and tributaries and for all of NYC/LI/coastal CT.

This almost has the look of a subtropical storm. And don't look now, but the long range Euro ensembles are showing a pattern flip to a colder and possibly snowy pattern in late December, as the MJO enters phases 8 and 1 and the northern hemispheric wave cycles move towards a major ridge in the NW, leading to troughing in the eastern US, bringing cold air - snow, though, would require just the right timing between cold and moisture and that can't be predicted accurately at this range.

 

[Knight Shift]

Some ridiculous rainfall amounts (6-10") in parts of the SE US from FL to VA, so far, and the NWS has upped the rainfall forecast for our area just a bit, to a widespread 2-4" (with the higher amounts inland and the lower amounts towards the coast) leading to fairly widespread minor to moderate stream/river flooding, as per the graphics below.

Wind forecasts have been increased a touch, also, as per the graphic below, with gusts to 50 mph at the NJ coast and even higher for NYC/LI and this is part of why widespread minor coastal flooding is predicted for much of the NJ/DE coasts and moderate coastal flooding is predicted for interior NENJ/NYC locations from the long fetch of SE winds piling water up the Hudson River and tributaries and for all of NYC/LI/coastal CT.

This almost has the look of a subtropical storm. And don't look now, but the long range Euro ensembles are showing a pattern flip to a colder and possibly snowy pattern in late December, as the MJO enters phases 8 and 1 and the northern hemispheric wave cycles move towards a major ridge in the NW, leading to troughing in the eastern US, bringing cold air - snow, though, would require just the right timing between cold and moisture and that can't be predicted accurately at this range.

Don't want to poke the bear, but just got back from a non-issue fire call run, and meh.
Looks like the heavy rain will hit between 1 and 4 a.m.

 

[RU848789]

Don't want to poke the bear, but just got back from a non-issue fire call run, and meh.
Looks like the heavy rain will hit between 1 and 4 a.m.

You can poke whomever you want, but it's way too early to dismiss this storm. The heaviest rains will be between now and 8 am, depending on where one lives - the last big wave from 5-8 am might be along and NW of 95, which could keep coastal areas down around 2" and put NW areas up around 3-4". You should likely get your 45-50 mph gusts at the coast.

 

[Knight Shift]

You can poke whomever you want, but it's way too early to dismiss this storm. The heaviest rains will be between now and 8 am, depending on where one lives - the last big wave from 5-8 am might be along and NW of 95, which could keep coastal areas down around 2" and put NW areas up around 3-4". You should likely get your 45-50 mph gusts at the coast.

My better half would violently disagree with your first part of your first statement! I will stick with the bear! 😉

 

[Joey Bags]

Already up to 1.38" here in Hunterdon with the main event just beginning. I have a feeling we're about to put up a number.

 

[Knight Shift]

Rain coming down hard here in South Monmouth and wind is whipping good. Just got back from another fire run. Wipers would not move fast enough to clear the windshield of rain.

 

[RU848789]

Flood warnings up all over the region from the NWS, especially along and NW of 95 and it's very likely there will be flash flood warnings issued in the next hour or two for specific places getting the worst of the rain/flooding. 1-2" of rain have fallen in much of the area and another 1-2" is likely in the next few hours. Numerous rivers/streams will be reaching moderate flood levels this morning and there could be major flooding in some locations.

The WPC issued a mesoscale discussion on the flooding risks, as per below. It's freakin' pouring out there. Might want to check your basements and be very careful if you have to be out driving in this. In addition, we've already seen numerous gusts over 40 mph and some gusts over 50 mph along/near the NJ coast with even higher gusts on LI.

https://www.weather.gov/phi/
https://forecast.weather.gov/wwamap/wwatxtget.php?cwa=PHI&wwa=flood warning

Mesoscale Precipitation Discussion 1206
NWS Weather Prediction Center College Park MD
210 AM EST Mon Dec 18 2023

Areas affected...Mid-Atlantic into southern New England

Concerning...Heavy rainfall...Flash flooding likely

Valid 180709Z - 181300Z

Summary...Deep convection continues to train along an axis from
Norfolk, VA to Salisbury, MD. 2 inch rainfall totals have been
noted in a few spots along this axis over the past three hours.
These heavier rain rates should continue to spread northeastward
toward southern New York, New Jersey, and southern New England
through 13Z. Flash flooding is likely.

Discussion...Recent observations indicate a heavy rainfall
scenario that is generally overperforming model guidance over the
past couple hours. Axes of heavy rainfall have materialized from
northeastern North Carolina to southeastern Maryland, and spots of
local axes of 2 inch/3-hr rain rates have developed especially
across urban areas of southeastern Virginia, resulting in flash
flooding. The axes are tied to 1) strong convergence along a warm
front extending north from a surface low near Wilmington, NC and
2) increasing instability, with SPC Mesoanalyses now indicating
1000-1500 J/kg MUCAPE along an axis located very near the front.
Deep southerly flow aloft was also allowing for training of deep
convection, further enabling the heavier rain rates despite
relatively quick cell movement.

Concern has increased that this focused axis of convergence and
instability will gradually extend northward through portions of
Delaware, New Jersey, and southern New York through 13Z this
morning, prompting heavy rainfall and flash flooding. These areas
are already experiencing rainfall now, which will only prime soils
and lead to minor flooding in low spots until heavier
precipitation moves in from the southwest. Again, areas of 2
inch/3-hr rain rates should exceed 3-hour FFG thresholds
(generally in the 1.5-2.5 inch range - lower in urban areas) and
result in potentially widespread flash flood potential across the
discussion area. Given current trends, flash flooding is
considered likely through 13Z this morning.

 

[RU848789]

Radar indicated rainfall through 4 am, showing almost all of the area getting 1" or more, with plenty of locations getting 2"+ so far with 1-2" more to come (or more in spots) for storm totals of 2.5-4.5" across the region, as per the updated NWS forecast. Flooding will be widespread over the next several hours. Max wind gusts, so far, are in the 2nd graphic (just for NJ).

 

[bac2therac]

61 degrees...approaching 3 inches imby

 

[rurichdog]

Rainfall totals for the last 24 hours to 3 days - high resolution map

Radar-estimated precipitation accumulation for the past 24 hours to 3 days. High resolution and interactive rainfall data on Google Maps.

www.iweathernet.com

 

[Postman_1]

Just drove from Hamilton to Somerset. There were road closures on a bunch of roads. I drove through two spots that weren’t closed but should’ve been. Brutal drive in. Hopefully not flooded on ride home

 

[rurichdog]

Just drove from Hamilton to Somerset. There were road closures on a bunch of roads. I drove through two spots that weren’t closed but should’ve been. Brutal drive in. Hopefully not flooded on ride home

Hamilton to Jamesburg for me. Route 130 is flooded in several areas in Robbinsville/Windsor area. People driving at normal speeds, then all of a sudden you'll see the edge of the road disappear, or the water is just sheeting across the road from one side to another. Going to be some bad accidents this morning.

 

[RUChoppin]

Hillsborough is trying to have a full day of school today, despite road closures at various points in town and the rain still coming down. They say buses may be delayed, but I just don't know how they're going to reach some kids... Let alone get them home.

 

[knightfan7]

1.7" so far in Sea Girt. Rain has been coming in waves.

As one of the maps showed, maximum wind gust was 53mph a bit before 4AM.

No coastal flooding worth mentioning.

 

[Joey Bags]

Hillsborough is trying to have a full day of school today, despite road closures at various points in town and the rain still coming down. They say buses may be delayed, but I just don't know how they're going to reach some kids... Let alone get them home.

Urban and small stream flood waters recede as quickly as they rise, the return commute will be fine.

 

[RULoyal]

Somerset County just sent out a Nixle to please stay off the roads and stay home if possible

 

[RUChoppin]

Urban and small stream flood waters recede as quickly as they rise, the return commute will be fine.

Hillsborough isn't urban and the South Branch of the Raritan isn't a small stream. Generally we still see increasing flooding for 8 to 10 hours after rain stops, as water runs down into the valleys.

Neighboring towns, including Branchburg, have already closed schools for today.

 

[RULoyal]

1.7" so far in Sea Girt. Rain has been coming in waves.

As one of the maps showed, maximum wind gust was 53mph a bit before 4AM.

No coastal flooding worth mentioning.

As of 6am

 

[Proud NJ Sports Fan]

You guys don’t have to worry about a drought for anytime soon.

 

[knightfan7]

As of 6am

Rutgers Weather Center station which is about a mile up the coast from me is what I use.

Can't get much closer.😀

 

[Ronnie_B]

As of 6am

Looks like the thick of the Pine Barrens will be a muddy slop for some time. Yikes.

 

[RU848789]

As of 6am

Same map of NJ, as of about 8:30 am. Impressive amounts with maybe another 1/4-1/2" possible, although coverage with that will be spottier. NWS nailed that the lowest amounts would be at the coast with rapidly increasing amounts towards 95, with a general 2.5-4.5", so far. Below that is the radar-indicated rainfall for the whole region, which is pretty similar for NJ. Pretty steep gradient from west to east, with much of LI only getting 0.75-1.5". Flood warnings and flash flood warnings all over the region, as others have noted. Be careful out there.

Wind gusts weren't much higher than what I posted at 4 am, although Seaside Heights reported a 61 mph gust, the highest gust in the region, surprisingly, as LI gusts were only reported in the 55 mph range. Tuckerton had a 56 mph gust and Belmar had a 55 mph gust reported. About 45K power outages reported in NJ as of this morning.

https://www.nj.com/weather/2023/12/...rce-storm-knocks-out-power-to-nearly-50k.html

 

[OTBOTOR]

My grill cover was loose, I guess. It's gone. And a few of the tall narrow junipers I planted in Spring have blown over :(

 

[ClassOf02]

If this were snow, we talking 2 ft+?

 

[RU848789]

If this were snow, we talking 2 ft+?

Rule of thumb is 10" of snow per 1" of rain, so this would've been an insane 20-50" of snow for most, although the colder the airmass, the less moisture it can hold, so a snowstorm likely would've been "capped" at 30-35" due to that. But yeah, we missed out on a biblical snowstorm.