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NYC CWA Feb 1-2 Storm Discussion


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with a low passing to the west, i cant comprehend how the MM5 shows what it shows. Cold surface temperatures are one thing, but the MM5 shows what looks like snow to me, and a decent amount of it.

the low isnt passing to the west...its transferring.

slp.54.0000.gif

57 hrs

slp.57.0000.gif

60 hrs

slp.60.0000.gif

DAMN IT- if only that 1045mb HP was in southern Canada instead of the Eastern Colorado

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Guest stormchaser

the low isnt passing to the west...its transferring.

slp.54.0000.gif

57 hrs

slp.57.0000.gif

60 hrs

slp.60.0000.gif

The MM5 shows a full transfer below 40N thus allowing NNJ/NENJ/NEPA/NYC and surrounding areas to stay all or mostly frozen.

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Guest stormchaser

A big thing, if not THE driving thing for NYC is how quickly the initial dies out and transfers to the coast. ANY earlier then what is being progged (or exactly what the MM5 solution is) would portray a more wintry situation for the area. If the initial hangs on longer then that gives the tri-state more time to experience a warm punch. IF the coastal gets the energy earlier then there IS cold air for it to tap into or at least hold onto, which is what the MM5 wants to do.

The HPC said the NAM is likely wrong with the initial SLP being so strong right? I would think this is a good thing for us because a weaker initial low means it can die off/transfer quicker and there is more potential energy for a coastal low.

Also, another thing to keep in mind is that the coastal lows we have had this year have developed quicker and at least 2-4 mb stronger then what guidance has had them developing at at any given time. Not that this will create huge forecast differences between a 1002 coastal and a potentially sub 1000mb coastal but it could have some small implications, and in a forecast uncertainty like this where 5-10 miles and 1-2 degrees could be the difference..... well you get where i am going.

Just my 2cents

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Based on the soundings I think both the GFS and NAM suggest some moderate icing potential for NYC with the first batch of precipitation tomorrow, after snow to start. The surface is very cold but shallow. The mid-levels actually look to cool just enough before the 2nd batch arrives late Tue night for a possible brief change back to snow, especially just north of the City. But by then surface temps look to have warmed sufficiently to mitigate the threat of freezing rain. Thereafter both ncep models suggest rain or barely freezing rain under near the end of the event.

The model differences appear most pronounced for Wednesday, especially north of the City. The GFS really torches the mid-levels right through the mid-hudson valley and pushes the surface slightly above freezing up past HPN. Up toward KSWF would be mostly snow/sleet (NAM) or freezing rain (GFS), the lower hudson valley would be sleet/freezing rain (NAM) or rain (GFS), and the City would be freezing rain (NAM) or rain (GFS). I am eager to see how temperatures for this 2nd round trend in the modeling today

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A big thing, if not THE driving thing for NYC is how quickly the initial dies out and transfers to the coast. ANY earlier then what is being progged (or exactly what the MM5 solution is) would portray a more wintry situation for the area. If the initial hangs on longer then that gives the tri-state more time to experience a warm punch. IF the coastal gets the energy earlier then there IS cold air for it to tap into or at least hold onto, which is what the MM5 wants to do.

The HPC said the NAM is likely wrong with the initial SLP being so strong right? I would think this is a good thing for us because a weaker initial low means it can die off/transfer quicker and there is more potential energy for a coastal low.

Also, another thing to keep in mind is that the coastal lows we have had this year have developed quicker and at least 2-4 mb stronger then what guidance has had them developing at at any given time. Not that this will create huge forecast differences between a 1002 coastal and a potentially sub 1000mb coastal but it could have some small implications, and in a forecast uncertainty like this where 5-10 miles and 1-2 degrees could be the difference..... well you get where i am going.

Just my 2cents

This makes sense to me, even with the NAM's stronger solution it was still colder which would give this MM5 more traction. Simply because a weaker solution would end up being a colder solution and as it is the NAM is REALLY close. Needless to say, we'll just have to keep monitoring.

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A big thing, if not THE driving thing for NYC is how quickly the initial dies out and transfers to the coast. ANY earlier then what is being progged (or exactly what the MM5 solution is) would portray a more wintry situation for the area. If the initial hangs on longer then that gives the tri-state more time to experience a warm punch. IF the coastal gets the energy earlier then there IS cold air for it to tap into or at least hold onto, which is what the MM5 wants to do.

The HPC said the NAM is likely wrong with the initial SLP being so strong right? I would think this is a good thing for us because a weaker initial low means it can die off/transfer quicker and there is more potential energy for a coastal low.

Also, another thing to keep in mind is that the coastal lows we have had this year have developed quicker and at least 2-4 mb stronger then what guidance has had them developing at at any given time. Not that this will create huge forecast differences between a 1002 coastal and a potentially sub 1000mb coastal but it could have some small implications, and in a forecast uncertainty like this where 5-10 miles and 1-2 degrees could be the difference..... well you get where i am going.

Just my 2cents

It seems like at least 7 times out of 10, primary mid-level lows move further north than expectation. If I were a gambler I would bet on slightly less snow to the north (with stronger southerly mid-level push) and slightly more sleet and ice to the south (with northerly surface component holding on).

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It seems like at least 7 times out of 10, primary mid-level lows move further north than expectation. If I were a gambler I would bet on slightly less snow to the north (with stronger southerly mid-level push) and slightly more sleet and ice to the south (with northerly surface component holding on).

Exactly, we've played this game many times before with primary lows driving to our west and waiting for them to transfer, only to find out that by the time it happened it was too late. Now who's to tell what this one will do, we dont know if it will be one of the 7 out of 10 or one of the few 3 out of 10 yet. My only point is that IF it happens a bit earlier then it would obv. be a more wintry solution. A bit later and its definitely going to be wet. (NYC area this is). A key will be watching that HP to the north and find out exactly how strong it is in regards to what is being modeled. If it winds up being stronger then modeled then the low will want to take the path of lesser resistance and move more quickly to the coast.

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oooh that 1/26 storm. It was BELOW zero in NYC that AM. I had a flight to Phoenix to visit a buddy at ASU.....I just got out before the storm...9 hours later is was in the 50's in NYC.....that was one crazy winter.

1/7/94 is the current #2 analog over the east for the next 36hrs. 2/9/94 is the #1. 1/26/94 is the #3.

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The models messed up in terms of timing and precipitation totals and most missed the first part of the storm, however they did a good job with precip type/track etc.

How can anyone believe the models this season with last weeks clusterfook , i guess their is redemption but come on you have to watch the radar its kind of fun not knowing whats going to unfold see ya.

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Although the MM5 would be great, it's likely prudent to not blend it into any forecast at the moment. It tends to have a bit of a cold and progressive bias at this range, and likes to follow alongside the NAM (which has the same issues).

We've seen this play before. Strong primary surface lows are not easy to kill off without blocking or strong confluence. The NAM is very often too cold in these synoptic setups while the GFS may run a tick too warm. I suspect that a SREF/ECMWF blend of thermal profiles and QPF is the best way to go at this point.

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One of the best analogs in terms of the upper level pattern (strong southern stream system moving ENE into well-defined confluence zone over Quebec, while energy remains behind in the SW US) is 1/19/1987.

http://www.eas.slu.e...=12&map=4panelA

http://www.meteo.psu.edu/~gadomski/NARR/1987/us0119.php

The surface pattern (primary tracking NE from lower MS Valley to Ohio, with redevelopment off southern NJ) is also similar, though the high over Ontario/Quebec was significantly weaker (only about 1020 mb).

It also produced significant snow just north of Tulsa, in Kansas City and St. Louis, and in the southern suburbs of Chicago.

The boundary between significant snow vs. ZR/IP ran from NE PA/far NW NJ eastward into southern RI and Cape Cod.

Because the preceding cold air mass wasn't very deep, there was only a thin strip of ZR and very little IP.

It was also followed 2-3 days later by a KU storm on 1/22/87.

1/7/94 is the current #2 analog over the east for the next 36hrs. 2/9/94 is the #1. 1/26/94 is the #3.

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Srefs have NYC surface temp below 32 thru hour 45.

.75"-1" of precip falls thru then for NYC on west.

At 48, the surface warms to just above 32 for NYC and thru 48, 1"-1.25" of precip has fallen.

Here is all the precip that falls thru hour 45, while NYC is in the 20's:

nznjp2.gif

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Srefs have NYC surface temp below 32 thru hour 45.

.75"-1" of precip falls thru then for NYC on west.

At 48, the surface warms to just above 32 for NYC and thru 48, 1"-1.25" of precip has fallen.

Here is all the precip that falls thru hour 48, while NYC is in the 20's:

nznjp2.gif

keep in mind the SREF mean has a lot of RSM members in it that are low resolution models and are stubborn on picking up on low level cold air compared to the ARW/ETA/NMM members. So the surface cold would likely hold on longer than that

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well, thru 18 hrs the 18Z would indicate that, at least for my area, we would see no snow at all. It is definitely warmer in the mid levels.

and by 27hrs is basically all rain. cool a bit at 30 but the layer of cold air is shallow

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Every single time a model is warm or not the best solution someone has some stupid excuse for it. Its getting ridiculous now.

What I said is correct though, Just look at how much QPF has dropped since the runs this morning. Terrible continuity. I still think I'm in for quite a storm, NYC not so much. We shall see though still early in the run.

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What I said is correct though, Just look at how much QPF has dropped since the runs this morning. Terrible continuity. I still think I'm in for quite a storm, NYC not so much. We shall see though still early in the run.

and i thought he was getting on the other people who always find a reason why the warm/no snow/less than ideal models are wrong....my bad

anyway- the 18Z nam isnt a good solution for anyone wanting frozen precip

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and i thought he was getting on the other people who always find a reason why the warm/no snow/less than ideal models are wrong....my bad

anyway- the 18Z nam isnt a good solution for anyone wanting frozen precip

It has NYC well below freezing thru hour 42:

nam_namer_042_10m_wnd_precip.gif

What are you talking about?

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It has NYC well below freezing thru hour

nam_namer_042_10m_wnd_precip.gif

What are you talking about?

stop looking at the ridiculous maps...

here-

http://www.twisterda...e&archive=false

always every level is over 0C, there is NO WAY that is anything but RAIN.

If you are talking westchester and rockland then YES its frozen...but im looking at it from my perspective (and i apologize for not clarifying that in my post)

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stop looking at the ridiculous maps...

here-

http://www.twisterda...e&archive=false

always every level is over 0C, there is NO WAY that is anything but RAIN.

If you are talking westchester and rockland then YES its frozen...but im looking at it from my perspective (and i apologize for not clarifying that in my post)

LOL

Your marker is centered about 50 miles south of LI in the Atlantic ocean. Of course they're getting rain there :lmao:

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URGENT - WINTER WEATHER MESSAGE

NATIONAL WEATHER SERVICE MOUNT HOLLY NJ

318 PM EST MON JAN 31 2011

...WINTRY PRECIPITATION IS EXPECTED FROM TONIGHT INTO WEDNESDAY...

LOW PRESSURE WILL MOVE FROM THE LOWER MISSISSIPPI RIVER VALLEY ON

TUESDAY TO THE UPPER OHIO RIVER VALLEY EARLY ON WEDNESDAY. THE

LOW IS THEN EXPECTED TO JUMP TO THE WATERS OFF NEW JERSEY ON

WEDNESDAY AFTERNOON BEFORE RACING TO THE NORTHEAST. THE WEATHER

SYSTEM WILL BRING A PROLONGED PERIOD OF WINTRY PRECIPITATION TO

PARTS OF OUR REGION FROM TONIGHT INTO WEDNESDAY.

NJZ001-007-008-PAZ054-055-061-062-011000-

/O.UPG.KPHI.WS.A.0004.110201T0800Z-110202T2200Z/

/O.NEW.KPHI.WS.W.0005.110201T0500Z-110202T2300Z/

SUSSEX-WARREN-MORRIS-CARBON-MONROE-LEHIGH-NORTHAMPTON-

INCLUDING THE CITIES OF...NEWTON...WASHINGTON...MORRISTOWN...

JIM THORPE...STROUDSBURG...ALLENTOWN...BETHLEHEM...EASTON

318 PM EST MON JAN 31 2011

...WINTER STORM WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 6 PM

EST WEDNESDAY...

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY HAS ISSUED A WINTER

STORM WARNING FOR A WINTRY MIX OF SNOW, SLEET AND FREEZING RAIN...

WHICH IS IN EFFECT FROM MIDNIGHT TONIGHT TO 6 PM EST WEDNESDAY.

THE WINTER STORM WATCH IS NO LONGER IN EFFECT.

* PRECIPITATION TYPES: SNOW LATE TONIGHT WILL MIX WITH SOME SLEET

ON TUESDAY DAY, A WINTRY MIX OF SLEET AND SNOW IS EXPECTED

TUESDAY NIGHT AND THEN TRANSITION TO FREEZING RAIN BY WEDNESDAY

MORNING BEFORE POSSIBLY CHANGING BACK TO SNOW WEDNESDAY

AFTERNOON.

* ACCUMULATIONS: CONFIDENCE IS LOW AS TO ACCUMULATION AS THEY ARE

PRECIPITATION TYPE DEPENDENT. BEST ESTIMATE IS 4 TO 10 INCHES OF

SNOW AND SLEET WITH THE HIGHEST AMOUNTS OVER THE HIGHER TERRAIN

OF SUSSEX COUNTY NEW JERSEY AND THE POCONOS. IN ADDITION ABOUT

ONE QUARTER TO HALF AN INCH OF ICE MIGHT ALSO OCCUR, GREATEST IN

THE LEHIGH VALLEY.

* TIMING: THE PRECIPITATION SHOULD OVERSPREAD THE REGION CLOSE TO

MIDNIGHT TONIGHT. THERE WILL BE A LULL IN THE PRECIPITATION

INTENSITY DURING TUESDAY AFTERNOON AND EVENING BEFORE HEAVIER

PRECIPITATION MOVES BACK IN OVERNIGHT TUESDAY AND WEDNESDAY

MORNING. PRECIPITATION SHOULD TAPER OFF WEDNESDAY AFTERNOON.

* IMPACTS: TRAVEL WILL BECOME DIFFICULT IN THE REGION FROM LATE

TONIGHT THROUGH WEDNESDAY AFTERNOON DUE TO SNOW AND THEN ICE.

ICE WILL ACCUMULATE ON TREE LIMBS AND UTILITY WIRES FROM TUESDAY

NIGHT INTO WEDNESDAY. WIDESPREAD POWER OUTAGES ARE POSSIBLE. THE

WEDNESDAY COMMUTE WILL BE EXTREMELY DIFFICULT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW...

SLEET...AND ICE ARE EXPECTED OR OCCURRING. STRONG WINDS ARE ALSO

POSSIBLE. THIS WILL MAKE TRAVEL VERY HAZARDOUS OR IMPOSSIBLE.

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stop looking at the ridiculous maps...

here-

always every level is over 0C, there is NO WAY that is anything but RAIN.

If you are talking westchester and rockland then YES its frozen...but im looking at it from my perspective (and i apologize for not clarifying that in my post)

I agree with your thoughts especially regarding the shallow cold air and the deep warm layer, but your marker is centered over Buoy 5545.

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