January 22nd-24th Nor'easter Observations & Discussions

Well I am off tomorrow and to bed shortly, wont be on the computer so probably will not be posting any maps, just posts mobile till monday so please everyone post wind snow rain maps until this storm is upon us, then we nowcast.

00z RGEM

Frank_Wx wrote:

00z RGEM

Late to the party was posted back few pages, pretty intense huh? how was the wedding?

Seas near 22 feet

jmanley32 wrote:

Frank_Wx wrote:

00z RGEM

Late to the party was posted back few pages, pretty intense huh? how was the wedding?

Long...good time though. Trying to catch up..

Frank_Wx wrote:

jmanley32 wrote:

Frank_Wx wrote:

00z RGEM

Late to the party was posted back few pages, pretty intense huh? how was the wedding?

Long...good time though. Trying to catch up..

Ya you probably not gonna like a page back, its been taken care of by janet (thanks). Do you still hold to your scroll with the current models (wind levels etc, seems frozen chances may have gone up?)? Take your time in looking at things not expecting a immediate response.

Frank_Wx wrote:

no inversion problems there that precip is intense and probably going to be when the highest winds will be yes? thats 4pm right? gonna be a real rough commute home, a nightmare.

jmanley32 wrote:

Frank_Wx wrote:

no inversion problems there that precip is intense and probably going to be when the highest winds will be yes?

Careful, there probably still would be above the 900-850 hPa level. An inversion isn't only based upon the precipitation and whether or not it will bring the winds with it. An inversion only describes the thermal profile of the atmosphere. So, you can have heavy precipitation falling, but if there is a steep inversion, like is being modeled, the winds above the inversion WILL NOT mix down because that part of the atmospheric column is stable (that's what an inversion is; cold and dense air located beneath warmer and less dense air). Because the cold air is already on the bottom and the warm air above it, the atmosphere has no need or "want" to mix it. Now, if we had an isothermal profile, or purely moist adiabatic profile, where temperatures were either steady with increasing height or gradually decreasing THEN we'd have all kinds of wind issues. Does that maybe explain it a little better? Make a little more sense?

rb924119 wrote:

jmanley32 wrote:

Frank_Wx wrote:

no inversion problems there that precip is intense and probably going to be when the highest winds will be yes?

Careful, there probably still would be above the 900-850 hPa level. An inversion isn't only based upon the precipitation and whether or not it will bring the winds with it. An inversion only describes the thermal profile of the atmosphere. So, you can have heavy precipitation falling, but if there is a steep inversion, like is being modeled, the winds above the inversion WILL NOT mix down because that part of the atmospheric column is stable (that's what an inversion is; cold and dense air located beneath warmer and less dense air). Because the cold air is already on the bottom and the warm air above it, the atmosphere has no need or "want" to mix it. Now, if we had an isothermal profile, or purely moist adiabatic profile, where temperatures were either steady with increasing height or gradually decreasing THEN we'd have all kinds of wind issues. Does that maybe explain it a little better? Make a little more sense?

LOL, not totally but i get general jist, so the 925mb winds will still mix down though likely? Or a portion of them that is, thats what we have been talking about in terms of the winds I am guessing, the 925mb level, are the 850s too high up to mix? I wasn't thinking 700hpa winds would mix down, is that even possible? Imagine 250 lol

Nonetheless the RGEM is a deludge, at hr 48 when its barely started already pushing 3 inches in southern to central jersey, guessing extrapolated out the NWS call for locally 4 inches is not out of question.  I am really curious to see what the winds actually end up being, if they fail then I really won't be taking the models seriously on that unless its a hurricane. Also noted that 850mb temps crash to -1 all way to coast, any frozen there? Not showing on maps but a boatload of sleet well N/W.

jmanley32 wrote:

rb924119 wrote:

jmanley32 wrote:

Frank_Wx wrote:

no inversion problems there that precip is intense and probably going to be when the highest winds will be yes?

Careful, there probably still would be above the 900-850 hPa level. An inversion isn't only based upon the precipitation and whether or not it will bring the winds with it. An inversion only describes the thermal profile of the atmosphere. So, you can have heavy precipitation falling, but if there is a steep inversion, like is being modeled, the winds above the inversion WILL NOT mix down because that part of the atmospheric column is stable (that's what an inversion is; cold and dense air located beneath warmer and less dense air). Because the cold air is already on the bottom and the warm air above it, the atmosphere has no need or "want" to mix it. Now, if we had an isothermal profile, or purely moist adiabatic profile, where temperatures were either steady with increasing height or gradually decreasing THEN we'd have all kinds of wind issues. Does that maybe explain it a little better? Make a little more sense?

LOL, not totally but i get general jist, so the 925mb winds will still mix down though likely? Or a portion of them that is, thats what we have been talking about in terms of the winds I am guessing, the 925mb level, are the 850s too high up to mix? I wasn't thinking 700hpa winds would mix down, is that even possible? Imagine 250 lol

You're so difficult lmfao jk jk ahaha yes. Here's how I would look at it: whatever you see at 925 hPa, those speeds are likely representative of the gusts that will be observed. So if you see 60 knots at 925, you can be fairly confident that 60 knot gusts will be the max gusts at the surface, give or take a few because of momentum transfer. For sustained winds, due to turbulent eddies and fluxes associated with things like precipitation and friction, a rough approximation would be to use about 50-60% of what you see at 925. Remember, sustained speeds are calculated as two-minute averages, not instantaneous values, which is also why the ratio is so low versus the gusts. In this scenario, because of the inversion (at least off that image posted earlier), 850s would be too high to mix, yes. Lastly, it is very possible to get winds at 700 hPa to mix down to the surface, even as high as 500 hPa can largely get mixed down giveknthe rigut conditions. Where do you think your winds in severe thunderstorms and micro-bursts come from?

Wow holy crud wind gusts offshore on Euro 104mph!!

rb924119 wrote:

jmanley32 wrote:

rb924119 wrote:

jmanley32 wrote:

Frank_Wx wrote:

no inversion problems there that precip is intense and probably going to be when the highest winds will be yes?

Careful, there probably still would be above the 900-850 hPa level. An inversion isn't only based upon the precipitation and whether or not it will bring the winds with it. An inversion only describes the thermal profile of the atmosphere. So, you can have heavy precipitation falling, but if there is a steep inversion, like is being modeled, the winds above the inversion WILL NOT mix down because that part of the atmospheric column is stable (that's what an inversion is; cold and dense air located beneath warmer and less dense air). Because the cold air is already on the bottom and the warm air above it, the atmosphere has no need or "want" to mix it. Now, if we had an isothermal profile, or purely moist adiabatic profile, where temperatures were either steady with increasing height or gradually decreasing THEN we'd have all kinds of wind issues. Does that maybe explain it a little better? Make a little more sense?

LOL, not totally but i get general jist, so the 925mb winds will still mix down though likely? Or a portion of them that is, thats what we have been talking about in terms of the winds I am guessing, the 925mb level, are the 850s too high up to mix? I wasn't thinking 700hpa winds would mix down, is that even possible? Imagine 250 lol

You're so difficult lmfao jk jk ahaha yes. Here's how I would look at it: whatever you see at 925 hPa, those speeds are likely representative of the gusts that will be observed. So if you see 60 knots at 925, you can be fairly confident that 60 knot gusts will be the max gusts at the surface, give or take a few because of momentum transfer. For sustained winds, due to turbulent eddies and fluxes associated with things like precipitation and friction, a rough approximation would be to use about 50-60% of what you see at 925. Remember, sustained speeds are calculated as two-minute averages, not instantaneous values, which is also why the ratio is so low versus the gusts. In this scenario, because of the inversion (at least off that image posted earlier), 850s would be too high to mix, yes. Lastly, it is very possible to get winds at 700 hPa to mix down to the surface, even as high as 500 hPa can largely get mixed down giveknthe rigut conditions. Where do you think your winds in severe thunderstorms and micro-bursts come from?

Gotcha, kinda difficult them cuz like RGEM doesnt have a gust map, and the surface map for some reason CMC maps do not bring the winds onshore even though they look like they should be, but dayumm euro.

Euro has a dangerous ice storm just west of NW NJ in PA, woah like a inche 1/2 of frz and its not over yikes!!.

Has timing changed on this seems like its going well into tuesday now.

Pretty sure WeatherBell has 925 maps for those. I think, not 100% though.

And I think it just is depending on how the evolution is handled. What the mid- and upper-levels do determines the precipitation, although I'm not really paying attention to timing.

rb924119 wrote:Pretty sure WeatherBell has 925 maps for those. I think, not 100% though.

they have 900hpa sustained, so lets see if i get the math right, hoping 900 is about same as 925.



So according to this map we can probably see sustained winds lets use NYC shading (60-64 kts). 41.4 mph to 44mph, thats at a 60% mix down.  If so the winds may have to be increased more towards 70mph gusts and even higher on LI.

Huge improvements at H5 on the Euro. Looks like the rest of tonight's suites so far. Further east and colder. Still working a warm nose in somewhere even for the northwest, so they're sleet, but it's gotta be a lot closer now. Any further and this could get real interesting. Has to be watched for further east movement. Have to look at soundings tomorrow and see where this warm tongue is. Probably still between 890-750 hPa if I had to guess. I'm going to bed happy, seeing as though all guidance went toward what I have been thinking over the last few days, and thought it would start showing at 12z today. Headed to bed. Happy tracking!!

jmanley32 wrote:

rb924119 wrote:Pretty sure WeatherBell has 925 maps for those. I think, not 100% though.

they have 900hpa sustained, so lets see if i get the math right, hoping 900 is about same as 925.



So according to this map we can probably see sustained winds lets use NYC shading (60-64 kts). 41.4 mph to 44mph, thats at a 60% mix down.  If so the winds may have to be increased more towards 70mph gusts and even higher on LI.

Yup, you have the right idea. Just remember where you mix from depends on the atmospheric profile and where the inversion starts, if there is one. Only way to know where that is on every model is to look at soundings for each one. But yes, you have the right idea. Just a slight tweak, 60% is the high end of that range, so 55% would probably be a bit safer. That would give you sustained winds right around 40mph, which sounds pretty reasonable atm.

Also, for reference, 900 hPa is slightly above 925; as you get closer to the surface the pressure increases. Think of gravity; out in space you float, on Earth you're anchored to the ground. Gravity has the same effect on the atmosphere.

rb924119 wrote:

jmanley32 wrote:

rb924119 wrote:Pretty sure WeatherBell has 925 maps for those. I think, not 100% though.

they have 900hpa sustained, so lets see if i get the math right, hoping 900 is about same as 925.



So according to this map we can probably see sustained winds lets use NYC shading (60-64 kts). 41.4 mph to 44mph, thats at a 60% mix down.  If so the winds may have to be increased more towards 70mph gusts and even higher on LI.

Yup, you have the right idea. Just remember where you mix from depends on the atmospheric profile and where the inversion starts, if there is one. Only way to know where that is on every model is to look at soundings for each one. But yes, you have the right idea. Just a slight tweak, 60% is the high end of that range, so 55% would probably be a bit safer. That would give you sustained winds right around 40mph, which sounds pretty reasonable atm.

Thats pretty bad for NYC, LI is really in for it as is jersey coast I did not do those calcs. Euro wind maps, back up there wow.

rb924119 wrote:Also, for reference, 900 hPa is slightly above 925; as you get closer to the surface the pressure increases. Think of gravity; out in space you float, on Earth you're anchored to the ground. Gravity has the same effect on the atmosphere.

Yes I know 900hpa is higher than 925 hpa just wasnt sure how much that would effect since u said 850s are too high to mix down. We should get some sleep, we will wake to even stronger winds and frozen precip : ) hopefully.

Dunno if anyone posted this yet, with the way models are looking this will likely be a warning tomorrow at some pt. (This a nearly 24 hr high wind watch, insane) Note the bottom, so this could cause a lot of power disruption. Not even the gusts sustained 40mph in treed terrain is bad. Bold for NWS Upton to say widespread, they usually do not use such wording with a watch let alone a warning.

CTZ009>012-NJZ006-106-108-NYZ071>075-078>081-176>179-221100-
/O.NEW.KOKX.FG.Y.0001.170121T2352Z-170122T1500Z/
/O.CON.KOKX.HW.A.0001.170123T0600Z-170124T0600Z/
SOUTHERN FAIRFIELD-SOUTHERN NEW HAVEN-SOUTHERN MIDDLESEX-
SOUTHERN NEW LONDON-HUDSON-EASTERN ESSEX-EASTERN UNION-
SOUTHERN WESTCHESTER-NEW YORK (MANHATTAN)-BRONX-
RICHMOND (STATEN ISLAND)-KINGS (BROOKLYN)-NORTHWESTERN SUFFOLK-
NORTHEASTERN SUFFOLK-SOUTHWESTERN SUFFOLK-SOUTHEASTERN SUFFOLK-
NORTHERN QUEENS-NORTHERN NASSAU-SOUTHERN QUEENS-SOUTHERN NASSAU-
652 PM EST SAT JAN 21 2017

...DENSE FOG ADVISORY IN EFFECT UNTIL 10 AM EST SUNDAY...
...HIGH WIND WATCH REMAINS IN EFFECT FROM LATE SUNDAY NIGHT
THROUGH LATE MONDAY NIGHT...

THE NATIONAL WEATHER SERVICE IN UPTON HAS ISSUED A DENSE FOG
ADVISORY...WHICH IS IN EFFECT UNTIL 10 AM EST SUNDAY.

* DENSE FOG...VISIBILITIES DROPPING TO ONE QUARTER MILE OR LESS.

* DENSE FOG TIMING...INTO SUNDAY MORNING.

* DENSE FOG IMPACTS...SIGNIFICANTLY REDUCED VISIBILITIES WILL MAKE
 TRAVEL DIFFICULT.

* HIGH WINDS...NORTHEAST 30 TO 40 MPH WITH GUSTS UP TO 60 MPH.

* HIGH WIND TIMING...STRONGEST WINDS WILL LIKELY OCCUR FROM MID
 MORNING MONDAY INTO MONDAY EVENING.

* HIGH WIND IMPACTS...DAMAGING WINDS WILL BLOW DOWN TREES AND
 POWER LINES. WIDESPREAD POWER OUTAGES ARE EXPECTED. TRAVEL WILL
 BE DIFFICULT...ESPECIALLY FOR HIGH PROFILE VEHICLES. LIMITED
 VISIBILITIES WILL MAKE TRAVEL VERY DIFFICULT.

Yes I know I don't sleep lol, holy 06z 4km NAM!

Snow/sleet/frz?



total precip!



WINDS 900hpa sustained! That white area offshore is 97mph winds! Take 55% thats 53mph sustained.

Warnings going up in NJ already.

NJZ012>014-222145-
/O.UPG.KPHI.HW.A.0001.170123T0700Z-170124T0000Z/
/O.NEW.KPHI.HW.W.0001.170123T0800Z-170124T0200Z/
/O.CON.KPHI.FG.Y.0002.000000T0000Z-170122T1500Z/
MIDDLESEX-WESTERN MONMOUTH-EASTERN MONMOUTH-
INCLUDING THE CITIES OF NEW BRUNSWICK, FREEHOLD, AND SANDY HOOK
344 AM EST SUN JAN 22 2017

...DENSE FOG ADVISORY REMAINS IN EFFECT UNTIL 10 AM EST THIS
MORNING...
...HIGH WIND WARNING IN EFFECT FROM 3 AM TO 9 PM EST MONDAY...

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY HAS ISSUED A HIGH
WIND WARNING...WHICH IS IN EFFECT FROM 3 AM TO 9 PM EST MONDAY.
THE HIGH WIND WATCH IS NO LONGER IN EFFECT.

* VISIBILITIES...ONE QUARTER MILE OR LESS AT TIMES.

* WINDS...EAST 30 TO 40 MPH WITH GUSTS UP TO 60 MPH.

* TIMING...THE STRONGEST WINDS ARE EXPECTED TO OCCUR DURING THE
DAY MONDAY. AREAS OF DENSE FOG WILL CONTINUE EARLY THIS MORNING.

* WIND IMPACTS...DAMAGING WINDS WILL BLOW DOWN TREES AND POWER LINES.
SCATTERED TO NUMEROUS POWER OUTAGES ARE EXPECTED. TRAVEL WILL
BE DIFFICULT...ESPECIALLY FOR HIGH PROFILE VEHICLES.

* FOG IMPACTS...REDUCED VISIBILITIES WILL MAKE TRAVEL DIFFICULT
EARLY THIS MORNING. IF DRIVING...SLOW DOWN...TURN YOUR LIGHTS
ON...AND LEAVE PLENTY OF ROOM IN FRONT OF YOU.