March 24-25 Potential Bomb Part Deux

[IsentropicLift]

A picture is worth a 1000 words and so is the current radar, which shows the precip getting eaten alive by the confluince as it tries to advance northward. Would not shock me if NYC didn't end up seing a flake tomorrow.

[ace0927]

What a horrible year decade for the Nam

fixed

[NEG NAO]

A picture is worth a 1000 words and so is the current radar, which shows the precip getting eaten alive by the confluince as it tries to advance northward. Would not shock me if NYC didn't end up seing a flake tomorrow.

that would be a top 5 bust for the last 10 years at least BUT can't jump ship[ after 1 run of the NAM since it was overdone to begin with up until a few runs ago - it has never handled this setup properly since the get go

[GD0815]

i do think the NAM is now too dry,but we'll see

NAM looks cracked out....528dm closed low southeast of NYC with a 992mb surface low 100 miles off the Delmarva and NYC is completely dry. I've never seen a precip shield so compact as the one that's being advertised with this storm. Either the models are correctly resolving an incredible degree of confluence or they're going down hard. I tend to find the CCB spreads out in coastals with less of a gradient than advertised by models, but with a few jackpot zones of heavier banding than expected. I keep waiting for the CCB to spread out and show more widespread QPF but it doesn't seem to be happening. 

[nzucker]

I mean it's a model so we shouldn't discount it. Now looking at this run, it surely went towards the Euro. It's still too close to comfort to up. I'm going to stick it out till the end with this one since it's the last chance of the season.

It's definitely not the last chance of the season...the 12z ECM shows the potential for snow showers Thursday as the ULL passes over the area with -8C 850s overhead. 

 

12z and 18z GFS also have the chance for a storm around 4/3, a time frame which has been signaled over and over again. The 18z tracks the low much further south due to the arctic airmass pressing southward with the unseasonable amount of cold air coming down from Canada. Definitely a threat if something like the 18z GFS verifies. We haven't had a decent April snowfall since 2006, and I think we might be overdue. If the high heights in eastern Canada hold on in this blocky pattern, there's a good chance for measurable snow in early April, and the 4/3-4/4 threat looks like the best chance. 

[IsentropicLift]

Taking a look at the high res simulated radars I counted only 4 or 5 panels (4 or 5 hours) where NYC gets into moderate precip. It goes from light to moderate to light and then back to moderate. The NAM also has 2m temps in the 40's for the entire area including Orange County and up to 45 degrees in NYC itself by 18z. Whatever falls, falls as rain or white rain.

 

[Absolute Humidity]

i do think the NAM is now too dry,but we'll see

That's sig worthy.

[NEG NAO]

Taking a look at the high res simulated radars I counted only 4 or 5 panels (4 or 5 hours) where NYC gets into moderate precip. It goes from light to moderate to light and then back to moderate. The NAM also has 2m temps in the 40's for the entire area including Orange County and up to 45 degrees in NYC itself by 18z. Whatever falls, falls as rain or white rain.

 

Mount Holly is taking some of the rain out of the forecast

 

 

NEAR TERM /UNTIL 6 AM MONDAY MORNING/    SNOW HAS STARTED ACROSS SRN DELAWARE AND CAROLINE COUNTY MD AS OF  900 PM. THE DRY AIR IN PLACE MAY RESULT IN MOSTLY SNOW OVERNIGHT  AND SOME OF THE RAIN HAVE BEEN REMOVED FROM THE OVERNIGHT GRIDS.  P-TYPE AND INTENSITY ARE TROUBLESOME VARIABLES IN THE NEAR TERM  PART OF THE FCST.     THE MODELS ARE ALL VERY SIMILAR IN RAPIDLY DEVELOPING A LOW  PRESSURE SYSTEM OFF OF THE VIRGINIA COAST WHICH WILL CAUSE AN  INITIAL PRECIPITATION BURST DURING THE MORNING. THE DIFFERENCES  COME WITH THE SECONDARY SURGE DURING THE AFTERNOON AS THE TROWAL  DEVELOPS. THE NON-US MODELS ARE FARTHER OFFSHORE AND SUPPORT  LIGHTER QPF AMOUNTS WHILE THE DOMESTIC MODELS WOULD HIT  SOUTHEASTERN/EASTERN NJ PRETTY HARD. THIS IS ALMOST A FLIP IN THE  FORECAST WE HAD GOING WITH THE BULK OF THE HEAVIER SNOW NORTH AND  WEST OF THE FALL LINE. WE HOPE OUR FLIP IS CORRECT AS WE HAVE  INCREASED SNOW AMOUNTS SE OF I95 WHILE KEEPING GENERALLY KEEPING  SIMILAR AMOUNTS NORTH AND WEST.  

[Momza]

A picture is worth a 1000 words and so is the current radar, which shows the precip getting eaten alive by the confluince as it tries to advance northward. Would not shock me if NYC didn't end up seing a flake tomorrow.

Local met calling this current precip not the main show, however not sure I buy that....

[PB GFI]

If you are a private forecaster how do you even consider this model when sending a forecast package out to you`re clients ?

 

I have to laugh at the tax dollars thrown at the development , the constant updating , analysis and monitoring of a model that simply doesnt work . IT HAS NO GOOD RANGE PERIOD ...

 

My apologies to the men and women at NCEP I know you work hard , but this product has shown zero continuity .The EC really needs a high res model that works . Major municipalities simply ignore the NAM now and thats a shame  .

[NEG NAO]

Local met calling this current precip not the main show, however not sure I buy that....

its not the primary is still down in Kentucky moving north the secondary coastal is not even developing yet

 

http://weather.unisys.com/sat_sfc_map_loop.php

[IsentropicLift]

Local met calling this current precip not the main show, however not sure I buy that....

This is true, this is over running precip from the primary low in the mid-west. It will get enhanced for a time tomorrow as the coastal takes over and moves out to sea. That is when we stand a chance at seeing some snow. The deformation banding stays just offshore per the latest NAM and most of the reliable guidance.

[winterwx21]

It's definitely not the last chance of the season...the 12z ECM shows the potential for snow showers Thursday as the ULL passes over the area with -8C 850s overhead. 

 

12z and 18z GFS also have the chance for a storm around 4/3, a time frame which has been signaled over and over again. The 18z tracks the low much further south due to the arctic airmass pressing southward with the unseasonable amount of cold air coming down from Canada. Definitely a threat if something like the 18z GFS verifies. We haven't had a decent April snowfall since 2006, and I think we might be overdue. If the high heights in eastern Canada hold on in this blocky pattern, there's a good chance for measurable snow in early April, and the 4/3-4/4 threat looks like the best chance. 

High temps are expected to be in the upper 40s Thursday. So I wouldn't be too interested in the snow shower threat for that day.

 

Anyway, it's amazing how bad the NAM is. Euro of course blows it away, but even GFS is far better than NAM. I've lost count of how many times the NAM has shown my area getting a foot+ of snow this winter from a storm. It hasn't happened once. 8 inches was my biggest storm. The NAM has been a complete and utter disaster this winter. Whenever it shows one of those huge solutions, all you can do is laugh. It's the ultimate weenie model, but most people here are smart enough to not fall for it.

[SnoSki14]

I actually think the models will follow the Nam, the trend has been s&e, the ULL is pressing further to the south increasing the confluence.

I would put money on the Gfs being either similar or drier than its last run.

Again it's a shame because if we had slightly less confluence, this would've been a significant storm for late March.

[GD0815]

That's sig worthy.

funny guy....it no longer matches the other guidance, may be it is a trend, but i am skeptical of a model that vacilltates so much

[NEG NAO]

This is true, this is over running precip from the primary low in the mid-west. It will get enhanced for a time tomorrow as the coastal takes over and moves out to sea. That is when we stand a chance at seeing some snow. The deformation banding stays just offshore per the latest NAM and most of the reliable guidance.

The NAM is reliable guidance ????? That NAM run is nonsense - goes from one extreme to the other fast the correct solution is somewhere in the middle

[RU848789]

Hey, maybe we get missed to the S/E, but then the storm stalls and we get saved by an inverted trough, pulling the precip back west, just like 3/8.  Surprised none of the desparate folks have brought that possibility up.  All kidding aside, though, if the NAM has finally "corrected" itself vs. the Euro and other models, and we don't see some moves to the N/W from the other models, it's looking like we won't be getting much accumulating snow and maybe not even much snow at all.  That would suck. 

[IsentropicLift]

The NAM is reliable guidance ????? That NAM run is nonsense - goes from one extreme to the other fast the correct solution is somewhere in the middle

Notice I said per the latest NAM and the reliable guidance, not....the latest NAM and the other reliable guidance.

 

Anyway it doesn't matter, 20 mile shift northest and we're talking, 20 mile shift southeast and we're all crying. Very tough forecast, but the writing is on the wall.

[Momza]

This is true, this is over running precip from the primary low in the mid-west. It will get enhanced for a time tomorrow as the coastal takes over and moves out to sea. That is when we stand a chance at seeing some snow. The deformation banding stays just offshore per the latest NAM and most of the reliable guidance.

Your OBS leans toward no flakes, from the current radar as per your last post. Would that be your thinking at he moment?

[NEG NAO]

Upton is just delaying the precip - does not agree with the NAM - is going with 21Z SREF

 

 

AREA FORECAST DISCUSSION  NATIONAL WEATHER SERVICE NEW YORK NY  1031 PM EDT SUN MAR 24 2013   SYNOPSIS    LOW PRESSURE IMPACTS THE REGION TO BEGIN THE WEEK. HIGH PRESSURE   THEN SLOWLY BUILDS IN FROM THE WEST THROUGH THE END OF THE WEEK  INTO THE WEEKEND.    

 

NEAR TERM /UNTIL 6 AM MONDAY MORNING/

TWO MAIN CHANGES THIS UPDATE. FIRST WAS TO RAISE MINIMUM TEMPERATURES A
TAD BASED ON IDEA THAT TEMPERATURES WILL NOT FALL OFF TO MUCH FROM
CURRENT READINGS BASED ON INCREASING CLOUD COVER AND INCREASING
WINDS LATE OVERNIGHT. THIS IS CONSISTENT WITH A BLEND OF 18Z
MAV/12Z MET GUIDANCE WITH 00Z NAM AND 23Z HRRR 2-METER TEMPERATURES.

SECOND ISSUE IS HOW SOON DOES PRECIPITATION MOVE IN -BASED ON
LATEST 21Z SREF/00Z NAM/18Z GFS SHOWING SLIGHT SLOWING TREND BASED
ON SLIGHTLY STRONGER RIDGE ALOFT HAVE ADJUSTED TO A DRY FORECAST
FOR OVERNIGHT.

 

 

 

SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/

AN EXAMINATION OF 18Z GFS AS WELL AS QUICK LOOK AT 21Z SREF AND
00Z NAM SUGGEST PRECIPITATION LIKELY WILL GET STARTED A TAD LATER.
AS FOR AMOUNTS - 18Z GFS WAS WETTER THAN 12Z GFS WHILE 00Z NAM
DRIER THAN 18Z AND 12Z NAM. 21Z SREF SEEMS FAIRLY CONSISTENT WITH
CURRENT FORECAST. BASED ON THE INCONSISTENT MESSAGE IN THE NAM AND
GFS AND SUPPORT FOR CURRENT FORECAST IN LATEST SREF - MADE NO
ADJUSTMENTS TO FORECAST IN SHORT TERM OTHER THAN TO BLEND IN
CHANGES MADE IN TEMPERATURES AND POPS IN THE NEAR TERM.

MONDAY EXPECTED TO BE A WET AND WINDY DAY WITH A COASTAL LOW
PASSING JUST TO THE SOUTH. THIS STORM WILL BRING ABOUT A COUPLE OF
CONCERNS FOR THE REGION...IN THE FORM OF PRECIPITATION AND WINDS.

MODEL GUIDANCE CONTINUES TO COME INTO BETTER AGREEMENT WITH
TIMING...WITH SOME DIFFERENCES STILL THOUGH IN THE TOTAL QPF
AMOUNTS...ESP MIDDAY MONDAY. 12Z NAM REMAINS THE WETTEST
SOLUTION...WITH THE GFS SLIGHTLY DRIER...AND 12Z ECMWF EVEN DRIER.
HARD TO GO WITH THE NAM SOLUTION WITH THE CONSISTENCY OF THE OTHER
MODELS...SO HAVE GONE WITH MORE CONSERVATIVE AMOUNTS...BLENDING
THE WPC WITH THE GFS AND ECMWF. THIS PRODUCES THE HIGHEST AMOUNTS
ACROSS THE COASTAL REGIONS...WITH LOWER AMOUNTS TO THE NORTH AND
WEST. SURFACE TEMPS WILL LIKELY TOP OUT IN THE MID TO UPPER 30S.
GFS TENDING TO BE THE WARMER SOLUTION...PUSHING TEMPS INTO THE 40S
ALONG THE COAST BY THE AFTERNOON. HOWEVER...THINKING WE SHOULD SEE
COOLING IN THE VERTICAL COLUMN WITH THE HEAVIEST PRECIPITATION
LATE MORNING AND DURING THE AFTERNOON...WHICH WOULD KEEP TEMPS IN
THE 30S. LEANED TO NAX WET BULB TEMPS FOR TEMPS DURING THE DAY
WITH THE PRECIPITATION ONGOING...RESULTING IN MAINLY A LIGHT TO
MODERATE SNOW EVENT. HOWEVER...IF THOSE TEMPS CAN WARM A COUPLE
MORE DEGREES IN THE AFTERNOON...COULD SEE SOME RAIN MIXING WITH
THE SNOW...MAINLY ALONG THE COASTAL REGIONS. ANY PRECIPITATION
AFTER 00Z SHOULD COME BACK TO LIGHT SNOW.

THE BEST FORCING CURRENTLY LOOKS TO BE OVER THE NYC METRO REGION
AND EAST...WHERE WE COULD SEE 2 TO 3 INCHES...WITH POSSIBLE 4 TO
5 INCHES IN ISOLATED AREAS. BECAUSE OF THESE TOTALS...HAVE ISSUED
A WINTER WEATHER ADVISORY FOR NORTHEAST NJ...NYC METRO...AND LONG
ISLAND. IF THE BANDING SETS UP FURTHER TO THE NORTH DURING MONDAY
AFTERNOON...COULD SEE THE NEED OF THE ADVISORY TO BE EXPANDED.
BECAUSE OF THE SURFACE TEMPS...ANY SNOW THAT OCCURS WILL BE WET
AND HEAVY IN NATURE.

IN ADDITION TO THE SNOW...GUSTY WINDS EXPECTED MAINLY DURING THE
DAY MONDAY. DEVELOPING LOW LEVEL JET OVER THE REGION WITH WINDS
BETWEEN 35 AND 45 KTS...COMBINED WITH A TIGHT PRESSURE GRADIENT
SHOULD PRODUCE GUSTS INTO THE 35 TO 40 MPH RANGE LATE MORNING
THROUGH THE AFTERNOON. HOWEVER...LOW CONFIDENCE OF REACHING WIND
ADVISORY LEAREA FORECAST DISCUSSION

 

NATIONAL WEATHER SERVICE NEW YORK NY  1031 PM EDT SUN MAR 24 2013   SYNOPSIS    LOW PRESSURE IMPACTS THE REGION TO BEGIN THE WEEK. HIGH PRESSURE   THEN SLOWLY BUILDS IN FROM THE WEST THROUGH THE END OF THE WEEK  INTO THE WEEKEND.    

[weatherbear5]

Hey, maybe we get missed to the S/E, but then the storm stalls and we get saved by an inverted trough, pulling the precip back west, just like 3/8. Surprised none of the desparate folks have brought that possibility up. All kidding aside, though, if the NAM has finally "corrected" itself vs. the Euro and other models, and we don't see some moves to the N/W from the other models, it's looking like we won't be getting much accumulating snow and maybe not even much snow at all. That would suck.

Every model could shift 150 miles to the NW bringing a blizzard to Buffalo, but in the end the models dont make the weather, so any sort of "shift" we see in these upcoming runs won't really mean diddly... It's about time to nowcast at this point. Slight variations in guidance are to be expected but the best way to nail this thing down is to simply watch the real time data as it comes in

I will say though I'll continue to watch the models though... Watching every model run of every model is a good way to pick up tendencies and biases and strengths and weaknesses so really I'd suggest doing so even if a particular model is pretty weak

[friedmators]

4KM NAM @ 500mb for 15Z tomorrow

RAP same time frame

 

[IsentropicLift]

Your OBS leans toward no flakes, from the current radar as per your last post. Would that be your thinking at he moment?

I think we see a lot of white rain during the day and a chance at some accumulating snows for southern and eastern sections after dark as the deformation banding brushes the area late in the day.

[PB GFI]

WEENIE RALLYING CRY ...

For you ANT .

 

...one-half a step too late or early,
and you don't quite make it.
One half-second too slow, too fast,
you don't quite catch it.
The inches we need are
everywhere around us.
They're in every break of the game,
every minute, every second.
On this team, we fight for that inch.
On this team, we tear ourselves...
...and everyone else around us,
to pieces for that inch.
We claw with our fingernails
for that inch...
...because we know when we add up
all those inches...
...that's gonna make the $%$%&
difference between winning and losing!

[MJO812]

The Euro ensembles have also been shaky of late.

[weatherbear5]

4KM NAM @ 500mb for 15Z tomorrow

RAP same time frame

The skewed nature of the RAP's map is giving me headaches trying to compare the two maps...

[Sundog]

4KM NAM @ 500mb for 15Z tomorrow

RAP same time frame

Looks practically the same. Only difference is the United States is not titled on one map and it is on the other.

[MJO812]

RGEM is all rain for the area with really little precip.

 

Here was the GGEM on March 22

 

http://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html

[WintersGrasp]

Cold north, warmer and drizzly here and cold south with snow

[SnoSki14]

RGEM is all rain for the area with really little precip.

Here was the GGEM on March 22

http://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html

It's a done deal.