North American Mesoscale Model Verification on January 26-27...

By: Zachary Labe , 10:34 PM GMT on January 29, 2011

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The North American Mesoscale Model (NAM) is a high resolution model courtesy of the National Center for Environmental Prediction. Another very common and referenced name for the model is the Weather Research and Forecasting Model (WRF). They are the same model and run out to 84 hours. The purpose of the model is to run a higher resolution determining mesoscale features that often cannot be picked up by the global models due to their larger scale. The NAM can be run on an 80km resolution with a broad view of the United States, or 40km which allows the viewer to zoom in on a localized region to put up on mesoscale features. Also a very high resolution form of the NAM exists using a 12km parametric and can zoom into different states. The model is released four times a day at 0z, 6z, 12z, and 18z. Keep in mind that time is zulu or more commonly known as greenwich mean time.

Computer models are critical to forecasting the weather as they use parametric and other mathematical equations to derive the current and predicted state of the atmosphere using a physical and chemical explanation as the background for the predictions. The NCEP is associated with the National Oceanic Atmospheric Administration (NOAA) to be the developer of these computer models. Each meteorological organization worlwide uses their own developed computer models to serve as a basis for the forecasts. Without computer models, we are not able to derive predictions on the weather greater than 24 hours out.

Like all computer models, the NAM shows all layers of the atmosphere in maps determining positioning and speed of the jet stream, surface precipitation amounts (quantitive precipitation forecast QPF), temperatures throughout the entire core of the atmosphere, convective indices, simulated radars, etc. Due to the higher resolution of the NAM, several problems do exist. It often produces convective elements in many middle latitude cyclones and these are known as convective feedback problems. This is where it developed these unstable regions and often associates them as surface lows causing the surface depiction to be distorted. This was a problem in the recent prediction of the January 26-27 winter storm and will be noted below. Also the NAM has a tendency to produce higher than normal precipitation amounts. I typically find myself cutting totals nearly by 30% as shown on the NAM. Finally the NAM has a bias to overamplify a low pressure and close them off to early particularily on eastern United States cyclogenesis off the coast.

The January 26-27 winter storm featured many model headaches do to some interesting variables. Early on it appeared likely for a low pressure to track up inland along the coastal plain. There was a lacking 50/50 low, unfavorable position of the western trough axis, neutral NAO, natural baroclinicity along the coastline, and stale antecedent cold air mass. This would produce rain along I-95 with heavy snows inland. The 500mb synoptic pattern showed very strong signals for this time of setup with most computer model guidance also in support. The GGEM and ECMWF led the pack with the heavy snows from I-81 on westward. The GFS suffered major problems with varying solutions for each run. But then the computer models began to delay the storm. In fact it was delayed nearly 48-60 hours from the original starting time. This caused a different scenario to unfold. The lacking high pressure to the north was still a problem as the anticyclone zoomed east-northeast, but now a high pressure and associated shortwave out ahead of it allowed sunk east-southeast across the Midwest and western Great Lakes. This acted as a 'kicker' helping to push the cyclonegenesis farther off the coast. This in turn allowed for a colder scenario along with precipitation to occur farther east. Therefore a turn of events allowed for a major I-95 snowstorm with 6in+ totals from Washington DC to Boston. This was very fortunate for snow lovers in that corridor due to pure luck given the poor synoptic setup.

Given the NAM's high resolution, it often overanalyzes prognostics post hour 60. It tends to enhance QPF, overamplify lows, and pick up on mesoscale features that really do not exist. Therefore I typically throw out hours 60-84. It would be a rare event where you would find the NAM 84 hour verifying anywhere close to accurate. But in the near term range, the NAM does an excellent job locating temperature thermals, QPF ranges, and picking up on mesoscale features; coastal fronts, enhanced convection, deformation bands, etc. But in this recent storm, it suffered a plethora of problems and even the 6 and 12 hour surface maps had poor verification especially in the QPF department.

Let us first look at the actual accumulated precipitation totals for the storm.

Given this is a 24 hour accumulated precipitation amount, about .01-.1in of additional precipitation fell south of the Mason-Dixon line in the previous 24 hours.

Here are the preceeding NAM total QPF forecasts...


(January 24; 18z) (January 25; 6z)


(January 25; 12z) (January 25; 18z)


(January 26; 0z) (January 26; 6z)

As you can see, the NAM had a lot of variance with the northwestern sharp precipitation gradients. These tight gradients this year have been caused by the rapid intensification of the coastal lows allowing the heaviest moisture to be confined closer to the center of circulation. Also in this instance, a very cold and dry air mass along with associated cold front was quickly advancing southeast across the Great Lakes and was even picked up on by the 700mb RH charts. This allowed the flow out of the northwest to dry up some moisture for areas more inland.

The NAM simulated radar vs. the forecast QPF did not match up. Often the NAM simulated radar showed the heavier mesoscale bands lining up in northern Maryland and southern Pennsylvania where as it only showed total QPF to be .25in-.5in. In fact looking at total verification, the NAM did very well for its simulated radar.


(Actual NEXRAD National Radar) (6z NAM January 26 Simulated Radar)

The NAM did seem to have a hold on the 500mb map showing the negatively tilted trough producing the coastal low along with the placement of the upper level low and associated shortwave kicker just to the west.


(18z NAM January 24; 500mb) (0z NAM January 26; 500mb)

In general the differences in the 500mb maps were very subtle with just a general strengthening in the closed 500mb low, which verified a tad north of the January 24 18z model run.

The NAM did a very excellent job in identifying mesoscale band using the UUV/700mb RH charts.

(6z NAM January 26; 700mb)

It indentifed the enhanced snow growth over southeastern Pennsylvania up through New Jersey and New York City. The problems with the NAM generally existed in the QPF fields. The model likely suffered a very convective feedback issues in QPF totals. This is why it is important to note other maps than surface maps to help locate the heaviest precipitation. The 700mb map screamed that snow totals would be farther inland with the enhanced deformation band and UUV rates. In general the high resolution models handled this the best with the HRR scoring an amazing victory for QPF along with the ECMWF. The GFS/NAM did a very poor job for QPF, but as noted above QPF does not always tell the story. Sometimes it is important to note other layers of the atmosphere to help make a forecast. This point is why many forecasters missed the boat. Many forecasters (especially broadcoast meteorologists) are drawn to the easy to understand QPF/surface maps, but one has to look at all layers of the atmosphere to make a prediction.

Lower Susquehanna Valley Doppler...

(Courtesy of WGAL)

"Here northeast of Harrisburg 2010-2011 winter statistics"
(Snow Stats)
Current Snow Cover- 0-3in
Monthly Total (November)- Trace
Monthly Total (December)- 0.6in
Monthly Total (January)- 18.90in
Monthly Total (February)- 1.35in
Seasonal Total- 20.85in
Winter Weather Advisories- 7
Winter Storm Warnings- 2
Ice Storm Warnings- 0
Blizzard Warnings- 0
Freezing Rain Advisories- 1
Winter Storm Watches- 2

(Temperature Stats)
Lowest High Temperature- 23.7F
Lowest Low Temperature- -1.7F
Wind Chill Advisories- 0
Wind Chill Warnings- 0

(Snow Storms Stats)
First accumulating snow - December 10 - 0.50in of snow
Clipper light snow - January 7-8 - 2.25in then another 1in of snow
Double Barrel Low - January 11 - 4.5in of snow
Coastal Low - January 17-17 - 1.8in of snow/sleet
Arctic Front - January 20-21 - 2.1in of snow
Upper level/coastal low - January 26 - 5.75in of snow
Two clippers - January 28-29 - 1.5in of snow

Ice Storm 2011... (Blizzard92)
.4-.5in of freezing rain
Ice Storm 2011...
Ice Storm 2011... (Blizzard92)
.4-.5in of freezing rain
Ice Storm 2011...
Ice Storm 2011... (Blizzard92)
.4-.5in of freezing rain
Ice Storm 2011...
Ice Storm 2011... (Blizzard92)
.4-.5in of freezing rain
Ice Storm 2011...
Ice Storm 2011... (Blizzard92)
.4-.5in of freezing rain
Ice Storm 2011...
Ice Storm 2011... (Blizzard92)
.4-.5in of freezing rain
Ice Storm 2011...
Ice Storm 2011 (Blizzard92)
Melting begins...
Ice Storm 2011
Ice Storm 2011 (Blizzard92)
Melting begins...
Ice Storm 2011

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1767. Hoynieva
2:28 AM GMT on February 22, 2011
Link
Member Since: January 20, 2009 Posts: 0 Comments: 1521
1766. Hoynieva
2:26 AM GMT on February 22, 2011
Quoting originalLT:
Hoy, what do you mean by "new feed"? I don't see anything different.


Basically a new blog, LT. Go out to the blog page and you'll see it.
Member Since: January 20, 2009 Posts: 0 Comments: 1521
1765. baxtheweatherman
2:24 AM GMT on February 22, 2011
At least 5 now and coming down hard with very low visibility. Schools actuality called a 2-hour delay the night before for once this school year, and not a bad idea.
Member Since: December 31, 2007 Posts: 0 Comments: 119
1764. originalLT
2:21 AM GMT on February 22, 2011
Hoy, what do you mean by "new feed"? I don't see anything different.
Member Since: January 31, 2009 Posts: 0 Comments: 8010
1763. originalLT
2:18 AM GMT on February 22, 2011
Congrats guys, down there in PA., you deserve your turn, hope you get 10" or more!! We wound up with about 5" in Stamford CT. Some reports of 7" in Greenwich CT. just 6 miles to my SW.
Member Since: January 31, 2009 Posts: 0 Comments: 8010
1762. Hoynieva
2:17 AM GMT on February 22, 2011
Blizz started a new feed in case some of you haven't noticed.
Member Since: January 20, 2009 Posts: 0 Comments: 1521
1761. TheRasberryPatch
2:15 AM GMT on February 22, 2011
right now air is still dry...a light coating and I am down to flurries.

temp 25F dewpt 14F humidity is increasing

Campbelltown, PA
Member Since: January 26, 2007 Posts: 72 Comments: 6276
1760. LivelySnow
2:07 AM GMT on February 22, 2011
Quoting Blizzard92:
0z NAM now has .5in QPF just north of the PA turnpike! We are going to get pounded tonight. Ratios are what are really going to push snow totals!


Wahoo!!!! I sure hope we do get pounded!!!! Bring it on!!!
Member Since: January 29, 2011 Posts: 0 Comments: 53
1759. Mason803
2:07 AM GMT on February 22, 2011
Quoting Blizzard92:
0z NAM now has .5in QPF just north of the PA turnpike! We are going to get pounded tonight. Ratios are what are really going to push snow totals!



agreed. temp here is 20f. blowing snow as well
Member Since: November 5, 2008 Posts: 0 Comments: 1139
1758. pittsburghnurse
2:02 AM GMT on February 22, 2011
white out conditions. Blowing and drifting. 1.5" per hour per spotter report.
Member Since: October 14, 2006 Posts: 1 Comments: 639
1757. wxgeek723
2:00 AM GMT on February 22, 2011
GRRR. Radar indicates moderate precip but NOTHING is reaching the ground. So frustrating...
Member Since: August 28, 2008 Posts: 79 Comments: 3713
1756. Zachary Labe
1:59 AM GMT on February 22, 2011
0z NAM now has .5in QPF just north of the PA turnpike! We are going to get pounded tonight. Ratios are what are really going to push snow totals!
Member Since: December 14, 2007 Posts: 285 Comments: 15140
1755. baxtheweatherman
1:56 AM GMT on February 22, 2011
Southwest of Altoona
Member Since: December 31, 2007 Posts: 0 Comments: 119
1754. TrentonThunder
1:55 AM GMT on February 22, 2011
Good to finally hear about the mod-hvy snow in central PA. Bring it this way...
Member Since: December 17, 2009 Posts: 0 Comments: 796
1753. TrentonThunder
1:53 AM GMT on February 22, 2011
Quoting baxtheweatherman:
4 inches so far- Roads are terrible.


Remind me where you're at again?
Member Since: December 17, 2009 Posts: 0 Comments: 796
1752. pittsburghnurse
1:51 AM GMT on February 22, 2011
Starting to look like a blizzard
Member Since: October 14, 2006 Posts: 1 Comments: 639
1751. TrentonThunder
1:50 AM GMT on February 22, 2011
nm
Member Since: December 17, 2009 Posts: 0 Comments: 796
1750. TrentonThunder
1:44 AM GMT on February 22, 2011
High pressure winning the battle the farther east and northeast you go. Eating it up like freakin Pacman! Not a good sign...

STATIONS <=39% RH AT 8PM
Cloudy throughout.......NNE Winds

Harrisburg: 29F / 7D / 39%
Reading PA: 29F / 5D / 36%
Quakertown PA: 28F / 5D / 37%
Blue Bell PA: 31F / 4D / 31%
Willow Grove PA: 30F / 4D / 33D / 33%
Northeast Philadelphia PA: 33F / 11D / 39%
Trenton NJ: 32F / 8D / 36%
Somerville NJ: 30F / 8F / 39%

STATIONS REPORTING PRECIP AT 8PM...NNE Winds
State College PA: Lgt Snow / 19F / 10D / 68%
Lancaster PA: Flurries / 30F / 13 / 45%
Coatesville PA: Lgt Snow / 32F / 16D / 51%
Philadelphia Int'l PA: Flurries / 35F / 16D / 45%
Baltimore MD: Lgt Rain / 33F / 25D / 72%
Washington DC: Lgt Rain / 33F / 25D / 72%
Georgetown DE: Mix / 36F / 32D / 85%
Member Since: December 17, 2009 Posts: 0 Comments: 796
1749. Mason803
1:43 AM GMT on February 22, 2011
Quoting Blizzard92:
Heavy snow here with a coating within the start 10min ago. Temperature falling rapidly now below 24F.


cracked an inch here with heavy snow currently. waiting for the low level jet
Member Since: November 5, 2008 Posts: 0 Comments: 1139
1748. TheRasberryPatch
1:42 AM GMT on February 22, 2011
snow just started here....one minute nothing the next it is coming down hard...no flurries to start.
temp 27F with dewpt of 9F
Campbelltown, PA
Member Since: January 26, 2007 Posts: 72 Comments: 6276
1747. KEEPEROFTHEGATE (Mod)
1:41 AM GMT on February 22, 2011
Member Since: July 15, 2006 Posts: 178 Comments: 56021
1746. Zachary Labe
1:38 AM GMT on February 22, 2011
Heavy snow here with a coating within the start 10min ago. Temperature falling rapidly now below 24F.
Member Since: December 14, 2007 Posts: 285 Comments: 15140
1745. KEEPEROFTHEGATE (Mod)
1:37 AM GMT on February 22, 2011
Member Since: July 15, 2006 Posts: 178 Comments: 56021
1744. baxtheweatherman
1:26 AM GMT on February 22, 2011
4 inches so far- Roads are terrible.
Member Since: December 31, 2007 Posts: 0 Comments: 119
1743. wxgeek723
1:23 AM GMT on February 22, 2011
Oh, yeah completely disregarded the AFD. Merci, TT. Now I'm getting a little apprehensive.
Member Since: August 28, 2008 Posts: 79 Comments: 3713
1742. TrentonThunder
1:12 AM GMT on February 22, 2011
Quoting wxgeek723:
I still don't think I'm following. NWS puts me at 100% chance for snow tonight with 2-4 inches. Is that just a conservative number? The forecast calls for steady snow 9pm-daybreak. Even if the snow takes time to get sticking to the ground, that seems a tad low.


Area forecast discussion
National Weather Service Mount Holly New Jersey
754 PM EST Monday Feb 21 2011


Synopsis...
low pressure over West Virginia this evening will move out to sea
east of Norfolk Virginia Tuesday morning.

Near term /until 6 am Tuesday morning/...
750 pm: no changes to the warning/advisory config at this time. Sort of waiting
on kmdt klns kthv to lower substantially as drying beneath the oncoming
lift is still dominant and eating up snow aloft. If I see it go to 1/2
MDT snow at kmdt or kthv at 9pm...will adjust amts up at that
time. Otherwise forecast going as constructed late today is working fine.


From The 5:30 PM update...
rrq of probable 250 mb speed maximum of 130 kts over
southern New England this evening coupled with the lfq of the 135 knots Ohio Valley
speed maximum heading for korf tomorrow morning is probably the
primary driver of lift. Surface winds in the warm sector across Kentucky at
5pm to 30 kts lifting 50+sfc dewpoints over ever colder low level
wedge of air pressing southward through New Jersey and PA behind this
mornings snow productive and eastward departing first low center.
The lift with this second low is already realized in PA with 1/2
to 1/2sm MDT to heavy snow from southern central PA through much of north
Ohio.


So while the 500 mb vorticity is moving into confluence between the northern
stream in New England and separate Ohio Valley upper level jet...the
lift should be excellent overnight and suspect 1-2/hour snowfall
rates for 2-4 hours in southern PA/North Maryland.. north del into S New Jersey. Exact placement
defines largest amounts. Will update west-southwest at 6pm for timing.


A substantial overnight travel problem looms as temperatures plunge below
freezing and snow begins with very hazardous travel expected in
the warning and advisory zones.


Gusty north-northeast winds of 25-30 miles per hour will cause some drifting during the
night.


Possible upgrade at 8 PM to a warning may be ahead for the region
in southeast PA SW of phl where am concerned about widespread 6 inch amounts.
Member Since: December 17, 2009 Posts: 0 Comments: 796
1741. TheRasberryPatch
1:11 AM GMT on February 22, 2011
From what i read from NWS for my area...the cold dry airmass is making it difficult for the snow to make it in to the area. they expect it to begin snowing by 10pm
Member Since: January 26, 2007 Posts: 72 Comments: 6276
1740. TrentonThunder
1:08 AM GMT on February 22, 2011
Some wild fluctuations in dewpoints in and around New Jersey. Dropping like a rock in some areas despite the virga. Weird...

Hourlies in Hamilton NJ

Cloudy throughout...
5pm, 34F, 24D, 68%
6pm, 33F, 24D, 68%
7pm, 33F, 23D, 66%
8pm, 32F, 17D, 54%
Member Since: December 17, 2009 Posts: 0 Comments: 796
1739. TheRasberryPatch
1:07 AM GMT on February 22, 2011
so far no snow here in Campbelltown, Pa...temp is 28F dewpt. 10F.
the radar is showing the snow all around. this has happened a few times to me this season...the radar in Blizz's blog has the area covered in blue except for a small triangle from harrisburg, to lebanon to lancaster.
Member Since: January 26, 2007 Posts: 72 Comments: 6276
1738. HeavySnow
1:07 AM GMT on February 22, 2011
Quoting bwi:
Is it just me or are they raising the forecast by the minute -- this latest for Greenbelt MD

Tonight: Snow and sleet, becoming all snow after 10pm. Low around 28. Northeast wind between 13 and 17 mph. Chance of precipitation is 100%. Total nighttime snow and sleet accumulation of 4 to 6 inches possible.

We're not even in the winter storm warning, but that's wsw criteria for us, I'm sure.


Drooooooool
Member Since: July 7, 2004 Posts: 18 Comments: 2990
1737. wxgeek723
12:58 AM GMT on February 22, 2011
I still don't think I'm following. NWS puts me at 100% chance for snow tonight with 2-4 inches. Is that just a conservative number? The forecast calls for steady snow 9pm-daybreak. Even if the snow takes time to get sticking to the ground, that seems a tad low.
Member Since: August 28, 2008 Posts: 79 Comments: 3713
1736. TrentonThunder
12:57 AM GMT on February 22, 2011
Quoting TheRasberryPatch:
Thanks TT. so there won't be any enhancement from the ocean?


Nope, it is what it is. What you see is what you get, maybe besides a little mountain lift and the usual higher ratios there.
Member Since: December 17, 2009 Posts: 0 Comments: 796
1735. pittsburghnurse
12:55 AM GMT on February 22, 2011
This is a beautiful snow. Perfect flakes. Heavy, dense and really coming down. Very nice. This will probably be our biggest snow of the season.
Member Since: October 14, 2006 Posts: 1 Comments: 639
1734. HeavySnow
12:48 AM GMT on February 22, 2011
Quoting Hoynieva:


I understand that this thing is dipping down to the SE, but with the precip shield extending as far N as it is and the precip already pretty far E, it would seem that our forecast for flurries in NYC is a bit too conservative. It looks like we'd get at least a dusting and at most a couple of inches.


Wrong again Stan!
Member Since: July 7, 2004 Posts: 18 Comments: 2990
1733. bwi
12:46 AM GMT on February 22, 2011
Is it just me or are they raising the forecast by the minute -- this latest for Greenbelt MD

Tonight: Snow and sleet, becoming all snow after 10pm. Low around 28. Northeast wind between 13 and 17 mph. Chance of precipitation is 100%. Total nighttime snow and sleet accumulation of 4 to 6 inches possible.

We're not even in the winter storm warning, but that's wsw criteria for us, I'm sure.
Member Since: September 4, 2007 Posts: 0 Comments: 1407
1732. bwi
12:43 AM GMT on February 22, 2011
Any thoughts on how dense the snow will be for central MD? Last time we got 5 inches, we lost power for a day!
Member Since: September 4, 2007 Posts: 0 Comments: 1407
1731. bwi
12:32 AM GMT on February 22, 2011
They've bumped me up to 3-5" Going to be an interesting commute tomorrow. Temp down to 36.
Member Since: September 4, 2007 Posts: 0 Comments: 1407
1730. PhillySnow
12:28 AM GMT on February 22, 2011
34.4F Light, intermittent snow so far. Amazingly, what little has fallen has stuck to the road.
Member Since: December 18, 2009 Posts: 0 Comments: 1271
1729. pittsburghnurse
12:10 AM GMT on February 22, 2011
We're getting heavy bursts with moderate snow in between. WSW 4-7". Heavy fat flakes but may be getting dryer as it gets colder. Looks like intensity increasing during the bursts. Got 0.5 in about 15 minutes.

Decided to take the car out of the garage on the chance it's closer to the 7 than the 4. Wouldn't want to have to dig my way out to the street. The tires can do it, but the mazda's low clearance is another matter.
Member Since: October 14, 2006 Posts: 1 Comments: 639
1728. Hoynieva
11:58 PM GMT on February 21, 2011
Quoting originalLT:
P451, I think they believe the storm will be deflected towards the south by a strong N to NW flow, so that precip won't make it to the Hudson Valley area.


I understand that this thing is dipping down to the SE, but with the precip shield extending as far N as it is and the precip already pretty far E, it would seem that our forecast for flurries in NYC is a bit too conservative. It looks like we'd get at least a dusting and at most a couple of inches.
Member Since: January 20, 2009 Posts: 0 Comments: 1521
1727. TheRasberryPatch
11:40 PM GMT on February 21, 2011
Thanks TT. so there won't be any enhancement from the ocean?
Member Since: January 26, 2007 Posts: 72 Comments: 6276
1726. TrentonThunder
11:33 PM GMT on February 21, 2011
Quoting TheRasberryPatch:
can someone give me the logistics with this evening's storm...is it moving west to east? coming up the coast? i haven't had the time to check any maps.


The low is moving west to east from northeastern Kentucky and is forecast to take a southeastern dive towards northeastern North Carolina. The only thing is that the precip shield extends a lot farther north right now than expected.
Member Since: December 17, 2009 Posts: 0 Comments: 796
1725. TrentonThunder
11:29 PM GMT on February 21, 2011
Looks like virga with moistening up to do northeast of a line from Harrisburg PA to Philadelphia PA.

At 6:25, I'm Cloudy with Virga, 33.1F, 24D, 68%

At 6:00 pm, Mount Pocono was Cloudy, 20F, -2D, 38%.

So you can see how dry the air is in northeast Pennsylvania with that high pressure centered over southeastern Canada and wedging its influence into northeast PA. This future interaction is the key to snow totals in eastern PA and central and northern New Jersey.

Stations reporting snow at 6:00 pm.

NEW CASTLE PA / SNOW / 27F / 25D
BEAVER COUNTY PA / SNOW / 28F / 27D
PITTSBURGH PA / SNOW / 29F / 26D
LATROBE PA / LGT SNOW / 32F / 32D
JOHNSTOWN PA / LGT SNOW / 25F / 21D
ALTOONA PA / LGT SNOW / 25F / 21D
YORK PA / LGT SNOW / 28F / 25D
HARRISBURG PA / FLURRIES / 31F / 17D
PHILADELPHIA PA / FLURRIES / 36F / 22D
MILLVILLE NJ / FLURRIES / 36F / 26D
Member Since: December 17, 2009 Posts: 0 Comments: 796
1722. TrentonThunder
11:12 PM GMT on February 21, 2011
Quoting Blizzard92:

Nope, I had a snow make up for school today. Radar looks about 25-50mi farther north than the 12z NAM. Tonight will be interesting to watch. Latest HRRR model is way north with heaviest snow accumulations from Altoona to Harrisburg to north of Philadelphia.


Ok, yeah I see how much farther north that shield is. By my perception, it seems that the shield is almost 100 miles north of where the 12Z NAM projected it at 6 pm. There is a serious battle going between the wedging high pressure and northern extent of precip north of I-80 (north of I-78 closer to Allentown PA) and east of Bradford PA. If you were to just look at the radar, you would think that the Pennsylvania Turnpike and along and just south of I-195 in New Jersey are in a prime position. NWS Mount Holly at the moment still at 1" here overnight. I'm sure (I hope) they're watching it closely.
Member Since: December 17, 2009 Posts: 0 Comments: 796
1721. wxgeek723
11:11 PM GMT on February 21, 2011
Light sleet/graupel moving into southern NJ.
Member Since: August 28, 2008 Posts: 79 Comments: 3713
1720. originalLT
10:55 PM GMT on February 21, 2011
P451, I think they believe the storm will be deflected towards the south by a strong N to NW flow, so that precip won't make it to the Hudson Valley area. Wow. that is some news about Bastardi, wonder where he will wind up. Maybe TWC?, he could team up with Jim Cantore, that would be quite a duo!
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1719. KEEPEROFTHEGATE (Mod)
10:16 PM GMT on February 21, 2011
Member Since: July 15, 2006 Posts: 178 Comments: 56021
1718. weathergeek5
10:16 PM GMT on February 21, 2011
Breaking news!!!! Joe Bastardi has left accuweather!!!! In other news, I am on campus some flakes are flying. Not much as of yet.
Member Since: December 25, 2005 Posts: 0 Comments: 1744
1717. TheRasberryPatch
10:15 PM GMT on February 21, 2011
can someone give me the logistics with this evening's storm...is it moving west to east? coming up the coast? i haven't had the time to check any maps.
Member Since: January 26, 2007 Posts: 72 Comments: 6276

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