Potential Major Storm for Eastern US for January 26-27...
Current wavelengths are supporting a large synoptic storm east of the Mississippi River Valley during the January 26th to the 27th with widespread moisture from the Southeaast to New England. This setup is corresponded with highly favorable teleconnections. The NAO (North Atlantic Oscillation) remains negative but has shifted the higher heights more east-based. This causes less blocking upstream. Blocking is typically associated with suppression and tracks of coastal lows well over 100mi off the coast. Also blocking allows for a slower movement of low pressures ushering in cold air to the right of the low in the large cold sector of the storm. When the blocking is allowed to relaxed or becomes displaced as in this instance, it allows cyclogenesis to often occur a bit farther to the west offering warmer air with a southeasterly flow off the Atlantic. This upcoming coastal threat will favor the later with dampened upstream blocking. Also the MJO (Madden-Jullian Oscillation) is entering phases 7-8. The MJO is a measure of the positioning of the monsoonal rains across the Indian Oceans. Since all global weather patterns are interconnected, differing wavelengths of pressure in the Indian Ocean will in time affect areas downstream in the jet stream across North America. Here is the current composite 500mb mean charts for an MJO phase 7 during January from a meteorological study by Allan Huffman...
Link
As noted above, increasing ridging across the western United States with a deep trough over the east coast often occurs. This corresponds to the current teleconnective pattern over North America with a positive PNA (Pacific/North American Pattern) which favors high pressure over the western United States coupled with upper level ridging.
The teleconnections are certainly signaling the classic jet stream setup for eastern cyclonegesis. But several 'issues' will likely prevent a major east coast snowstorm for areas in the major metropolitan region of the United States. Paul Kocin and Louis Uccellini's monograph of Northeast snowstorms signals the classic setup for widespread historical snowfalls to be accompanied by an arctic high pressure to the north of the storm. Typically we would root for a large anticyclone to the north or north-northeast of New England across southern Canada. This helps usher in cold air funneling in the western periphery of the low pressure. Also this helps prevent the low pressure from running too far inland.
The current synoptic setup shows the high pressure to the north of the low quickly scooting to the northeast and eventually too far east to save many from the expected rainfall. The 1/21/11 12utc ECMWF shows the banana high displaced to the east in an unfavorable location.
Kocin/Uccellini's near miss historic east coast snowstorm often featured a high pressure in a similar displaced location. Typically this would then favor inland snows with a mix or rain across eastern areas. While a severe arctic air mass will be in place along with a fresh snow pack over the Northeast, oftern these air masses can disperse quicker than one would assume. Current GGEM/UKMET/ECMWF guidance supports the upper level trough becoming negatively tilted towards the easteern Mississippi Valley. With these higher amplitude trough, the banana high is quick to depart and allows the cyclogenesis to occur farther along the coast. The 1/21/11 12utc GFS shows this evolution a tad differently, but does appear to be an eastern outlier. The 12utc GEFS mean shows a farther west solution, which often argues that the operational model is too far east. Most of my analogs support the heaviest snows well northwest of I-95 as warmer invades from the east. Despite several global models showing the low becoming vertically stacked allowing H85s to crash, there will likely be a southeast maritime flow across eastern areas.
The track of the H5 low tracks across Virginia, which is a bit too far north for a favorable snowstorm for most areas south of Washington DC for certain. Given the departing arctic air mass I would expect areas that receive mainly rainfall still to receive snow accumulations on the front end of the storm. The ECMWF mentioned earlier supports a quick 4-8in along most of I-95 before rainfall.
At this point, those farther east will be hoping to look for the 500mb low to track farther south, the banana high to become more situated north and not northeast, and the exact placement of the negatively titled trough.
While the threat is several days away, current climatology and guidance supports a very high threat of a large storm system over the eastern United States in this time frame. Whether it is rain or snow, there appears to be a large amount of moisture involved with ECMWF QPF up to 4in in northern Delaware and southeastern Pennsylvania. I know many are critical of predictions of storms well in advance, but meteorology is about understanding the synoptic setup that leads to the development of these storms. Watching the evolution of this situation will be very interesting and I am becoming increasingly enthused for those well inland. Even along the coast heavy rain and high winds are possible with a western storm track so threats will be high with any storm scenario. Stay tuned for updates throughout the weekend. For now if I had to make a forecast, this would be the precipitation scenario map.
The exact placements of the trough/shortwaves/high pressures will change, but I have not seen such consistency in the computer models for a large event in a very long time. This is also backed up by a favorable wavelength pattern as mentioned earlier in the blog. I think there is a higher possibility of this tracking farther west and inland than it tracking east. The odds of all snow along I-95 to the coast remain low given the departing high pressure. Another concern is the poor modeling this winter and the trend for storms to phase later than expected. Something to keep reminded of... Stay tuned!
Short Computer Model Introduction
This is a pretty decent quick intro on computer model forecasts along with beneficial links. Computer models use the complex calculus algorithms to print out the forecasts. Despite our complaning with the models, without them much of us would be lost except in the short time. Some of the earlier computer models consisted of the ETA, NGM, and AVN, which forecasted generally less than 84hrs. They were highly inaccurate, but provided a basis. The ETA was actually the computer model that helped meteorologists predicted the "storm of the century" in March of 1993 so well in advance. But now more than ever we have a myriad of computer models available to the general public with many mesoscale models only available to NOAA. Lets start with the general. All current computer models are based off on the Zulu time. Zulu time is also known as UTC or Greenwich time . Generally to forecast timing of storms my special BUFKIT data transitions UTC time to EST time, which is helpful. But BUFKIT is a special download, which I won't get into, but the transition is helpful as for some reason I never am able to understand time zones too well, hahaha. Anyways let me start with each computer model...
-GFS (Mentioned most of all as it is a global model (Global Forecasting System))
~Available in 0z (initiates at 10:30pm), 6z (initiates at 4:30am), 12z (10:30am), 18z (4:30pm)
~Forecasts out to 384hrs
~Typical biases
Cold bias on long range on 18z run
6z and 18z slightly unreliable
Northwest trend on lows within 84hrs of event
-ECMWF (This is another global model run by an international organization (European Centre for Medium-Range Weather Forecasts))
~Available in 0z (initiates at 1:30am), 12z (initiates at 1:30pm)
~Forecasts out to 240hrs
~Typical biases
Overphases lows in 168hr range
Holds too much energy in southwest
Known as extremely accurate within 140hrs
-NAM (Mesoscale short range model)
~Available in 0z (Initiates at 9:30pm), 6z (Initiates at 3:30am), 12z (initiates at 9:30am), 18z (Initiates at 3:30pm)
~Forecasts out to 84hrs
~Typical biases
Highly inaccurate towards the 84hrs
Handles coastal storms very well and southwest overrunning events
Tendency for way too much QPF
Those three above are the most common models for a beginner in computer models, but there are many more. All of the global models consistent of ensemble models also, such as the GFS has a myriad of ensemble (small models) that create a mean solution known as GEFS. They typically are too cold and southeast with low pressures, but some reason the NWS seems to enjoy using them. There are also more global models than the GFS and ECMWF... The UKMET is run by an internation organization and forecasts out to 144hrs. This model typically comes out an hr before the ECMWF and usually is pretty similar to the ECMWF. The ECMWF may also be known as the EURO by the way. There is also a Canadian model known as the GGEM/CMC, which again contains ensemble models. All of the internation models only run 0z and 12z runs. This is probably for the best as all models only receive new upper air data in 0z and 12z runs, so this is why the American model runs of the 6z and 18z are usually worthless. There is also a high resolution Canadian model known as the RGEM, which is very similar to the American NAM. High resolution (mesoscale models) are important as they usually are able to pick up on fine details such as frontogenesis, advection, adebiatic cooling, convection, etc. Some of this high resolution models include the WRF, HIRES NMM, RUC, ARW. They all are usually very accurate, but the WRF and HIRES NMM usually have wet bias.
As mentioned above there are ensemble models which come up with a mean solution instead of using one computer model's algorithms like the global models use. These ensemble mean solution are known as the MREF and SREF with MREF being in the medium range and SREF in the short range. SREF is usually pretty accurate and forecasts within 87hrs of an event. There are also other computer models used for hurricane forecasting, but I will not get into them. For instance one is the GFDL, which you may have heard of. I find I use mainly the GFS, NAM, and WRF/NMM in the summer, but use all of the models in the winter.
A few models to avoid...
JMA
KMA
CAMPASS
DGEX
Here is a list of links for explanations on how to interperate the models...
-PennState E Wall, which runs all of the models
http://www.meteo.psu.edu/~gadomski/ewall.html
-PennState E Wall tutorial on computer models (Check it out)
http://www.personal.psu.edu/adb241/eWallTutorial/ Main.htm
-Severe Weather parameters used on models, explanation
http://www.crh.noaa.gov/sgf/n=severe_weather_chec klist_paper
-Forecasting winter weather
http://www.crh.noaa.gov/lmk/soo/docu/precip_type. php
-NCEP; used to find American Computer models
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/
-Severe Weather Models
http://www.wxcaster.com//conus_0012_us_models.htm
-Winter Weather Models
http://www.wxcaster.com/conus_snowfall.htm
-Model Soundings
http://wxweb.meteostar.com/sample/sample.shtml?te xt=KMDT#
The last link is listed above as model soundings which takes all of the data to print out all sorts of information including precipitation type along with dynamics such as Omega. This is very complex and takes some time getting used to. Also you may see this data instead of in charts, it is sometimes used in SKEWT T charts.
I hope all of this information helped out... Keep in mind precipitation amounts is QPF, with 500mb aloft being the jet stream, 700mb aloft measuring relative humidity, 850mb aloft measuring 5,000ft aloft temperatures, 925-1000mb measuring surface temperatures. Generally I would look at the GFS and NAM first to get a hang of it along with reading the tutorial links. Use the 850mb and 2m charts for the GFS especially as they are pretty self explanatory and color coded. You will find some maps for international models are confusing and black and white.
"Here northeast of Harrisburg 2010-2011 winter statistics"
(Snow Stats)
Current Snow Cover- 1-4in
Monthly Total (November)- Trace
Monthly Total (December)- 0.6in
Monthly Total (January)- 11.65in
Seasonal Total- 12.25in
Winter Weather Advisories- 5
Winter Storm Warnings- 0
Ice Storm Warnings- 0
Blizzard Warnings- 0
Freezing Rain Advisories- 1
Winter Storm Watches- 1
(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
Clipper light snow - January 7-8 - 2.25in then another 1in
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
Lower Susquehanna Valley Doppler...
(Courtesy of WGAL)
This is the most difficult forecast I have ever had to make for the region. The gradient is going to be very sharp across the north and will make for a very high bust potential. This map is a bit bullish for northern areas. We shall see. Enjoy!
"Here northeast of Harrisburg 2010-2011 winter statistics"
(Snow Stats)
Current Snow Cover- 4-8in
Monthly Total (November)- Trace
Monthly Total (December)- 0.6in
Monthly Total (January)- 18.15in
Seasonal Total- 18.75in
Winter Weather Advisories- 6
Winter Storm Warnings- 1
Ice Storm Warnings- 0
Blizzard Warnings- 0
Freezing Rain Advisories- 1
Winter Storm Watches- 1
(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
Reader Comments
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The National Weather Service in Mount Holly has issued a Winter
Storm Watch...which is in effect from late tonight through
Thursday morning.
* Precipitation type: mixed snow...sleet and rain is expected
Wednesday...turning to a period of heavy snow Wednesday evening
before ending just after midnight.
* Accumulations: 4 or more inches of snow...with a coating of ice
possible embedded within the event.
* Timing: mixed precipitation will start Wednesday morning between
4 am and noon. Most intense period of snow and widespread
hazards is expected between 5 PM and midnight.
* Impacts: the Wednesday evening commute should be affected as
accumulating snow falls. The Thursday morning commute could also
be affected because of residual clean up of the wintry mess expected
Wednesday.
* Confidence: highest confidence for substantial winter weather
problems is near the Interstate 95 corridor. Lowest confidence
is in southern New Jersey from near Atlantic City southwestward
to central Delaware.
Precautionary/preparedness actions...
A Winter Storm Watch means there is a potential for significant
snow...sleet...or ice accumulations that may impact travel.
Continue to monitor the latest forecasts.
lol.. thats wrong. but, i agree. stay sick buddy.
Huh?? ACY 12"??????
I always thought Philly would be in the game. That's been the long-term pattern for the last couple of years, and there's been nothing to suggest it would change. If anything, the heavier snows have been traveling northeast, as we've seen. Snow breeds snow. I know it's got to be frustrating for everyone inland, but them's the breaks.
I have to wonder if we're switching back to a colder climatic cycle for the coastal plain, perhaps similar to the early-1800s, if not as intense.
That's true. We have been winning a lot the last few years (save for 2006-2007/2007-2008)
I saw that too...what gives?
My guess is we'll eventually be in one, but maybe they just want to make sure of how much rain/mix we'll get prior to the snow. It could just end up being an advisory. Looks like the big winners again are going to be in Eastern CT, and much of Massachusetts.
I can understand the hesitation - it's been a rainstorm all week, and it's just in the last couple of days that things have pointed toward significant snow. Money's tight right now, and municipalities are not going to appreciate it if the NWS tells them to get all their snow clearing equipment ready, and it turns out there's no need.
.. Winter Storm Watch in effect from Wednesday afternoon through
Thursday morning...
The National Weather Service in Upton has issued a Winter Storm
Watch... which is in effect from Wednesday afternoon through
Thursday morning.
* Locations... northeast New Jersey... the New York City
metropolitan area... Long Island... and coastal Connecticut.
* Hazards... heavy snow... with a period of a rain and sleet mix at
the onset.
* Accumulations... 6 or more inches of snow.
* Winds... northeast winds of 10 to 15 mph Wednesday
afternoon... becoming north and increasing to 15 to 25 mph with
gusts up 30 mph Wednesday night... then turning northwest Thursday
morning. Highest winds east.
* Timing... Wednesday afternoon into Thursday morning.
What I read is that they expect the snow to be very wet and a lot of it will melt before any starts sticking.
Theirs is one of the conservative maps, though. Still hard to say what we're going to get, but we're in the game! :)
I was thinking the same thing. This fella is big and nasty, with a comma formation even before bombing out in the Atlantic.
Was thinking the same thing - can't see how a ppt. shield that reaches from the Atlantic back to Texas is going to somehow impact an area only 50 miles wide once up in the northeast.
Can't say I'll be sorry though if it misses me - I want no part of that cement type snow... as long as this flushes in more cold to keep the powdery stuff we have up north I'll be perfectly happy.
Like I said, we are all going to be pleasantly surprised. Will there be a contest for this storm???
Are you allowed to win twice? Where's gaara...
THE NATIONAL WEATHER SERVICE IN BALTIMORE MD/WASHINGTON HAS
ISSUED A WINTER STORM WATCH...WHICH IS IN EFFECT FROM WEDNESDAY
AFTERNOON THROUGH LATE WEDNESDAY NIGHT.
* PRECIPITATION TYPE...BECOMING ALL SNOW DURING LATE AFTERNOON AND
EVENING.
* ACCUMULATIONS...5 OR MORE INCHES OF SNOW POSSIBLE.
* TIMING...SNOW STARTING DURING THE LATE AFTERNOON AND EARLY
EVENING. ENDING AFTER MIDNIGHT FROM SOUTHWEST TO NORTHEAST
WEDNESDAY NIGHT.
* TEMPERATURES...MID TO UPPER 30S WEDNESDAY...DROPPING TO THE
LOWER 30S BY THE EVENING. THE UPPER 20S WEDNESDAY NIGHT.
* WINDS...NORTHEAST 10 TO 15 MPH WEDNESDAY...BECOMING NORTHWEST
AROUND 15 MPH WEDNESDAY EVENING.
Id say its harder to repeat in guess the high snow total and location, than any other sport. But I've got a town in mind, so look out!!!!!!!!!!!!!
UNV: .44
MDT: .78
HGR: .95
LNS: .79
DUJ: .17
JST: .47
What's wrong with THIS picture?
Ummmm, you have been left out, AGAIN
It's too soon to feel this forecast is final, PP. I suspect all the forecasts right now. I'm still doubtful because I very rarely see rain change to snow here. NWS says the storm will pull in cold air, and that would be a new one for us!
Gonna be more!! Many are looking at this thing and saying that it is much juicier (is that a word?) than the models are showing which could lead to even higher qpf's. Just another reason to eagerly await the next model runs. Looks like poor Blizz finally had to head back to school just when things are looking up. He will be happy when he gets home.
But the more moisture in this thing would mean more rain, instead of snow, due to the ocean waters being warm right?
yea we still have some day light left but they did say temps would still go up as night falls...my forcast high is about 40 and currently at 34. i see your point.
Yeah, that's what some of us we're talking about earlier, zotty. The clouds and snow helped keep the temps down. We're now at 35 and I think that's probably the high.
Forecast high for Newark,De today was 41* Its 35* at 1:45pm. I dont think we are going to make it.
It did get up to 32 now with the sun out down here. 36 was forecasted
Forecast high for Brunswick, ME was 20°
It has made it up to 13
Temp. 47.2 at 2pm.
We are now under a WWA-says maybe up to 5 inches snow tomorrow overnight.
This has to be the strangest couple of days of forcasts I can remember for some time.
Blizz, come home from school and straighten them out, what is really going to happen?
http://www.weather.com/outlook/weather-news/news/articles/northeast-winter-storm-late-january_2011- 01-24?page=2
Philadelphia on GFS: 6 to 12 inches of snow.
Philadelphia on NAM: 12 to 16 inches of snow.
PP, where do you get your Euro QPF?
I pulled it from Americanwx.com's CPA thread from some of the Meteorologists that post there.
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