Phasing Storms







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This page is about storm systems in North America that can be characterized by two or three upper level lows (or vortices or troughs) that merge together to create a bigger or more intense storm, sometimes resulting in a snowstorm.



Midwest Blizzard of '78



January 24-27, 1978 250mb loop 850mb loop Surface Temp and SLP loop

Essentially Two-vort max powerful phasing. Did three branches of the jet stream phase together You decide: 500mb Wind Speed Loop (0.2MB) 250mb Wind Speed Loop (0.2MB)



Superstorm East Coast storm.



March 12-14, 1993 NARR animation NCEP Reanalysis Animaton 250mb loop 850mb loop Surface loop

Three-vort max powerful phasing



March 13, 1993 12z 300mb wind speed

Washington Blizzard of '66 East Coast Storm - Two-vort max powerful phasing



January 28-31, 1966 250mb loop 850mb loop Surface Temp and SLP loop

Did three branches of the jet stream phase together? 500mb Wind Speed Loop (0.2MB) 250mb Wind Speed Loop (0.2MB)



Northeast Blizzard of '78: East Coast Storm. I think this at least partly had phasing. It's interesting to note the surface low did a small loop near Cape Cod and Long Island. February 5-8, 1978



February 1958 East Coast Snowstorm. This loop is 7 days long - you can see one storm develop offshore and phase with the polar vortex and then move to Newfoundland before the February 16-17 storm (the real snowstorm.) This looks like it just might be Three-vort max phasing on February 16-17. 500mb loop of February 12-19, 1958 250mb loop 850mb loop surface temp and SLP loop



December 1960 East Coast Snowstorm. This seems to be pretty good Two-vort max phasing. 500mb loop of December 10-13, 1960 Surface loop



February 1995 East Coast Snowstorm. 500mb loop of February 2-4,1995



February 1983 East Coast Snowstorm. 500mb loop of February 10-13, 1983



Other Strong Phasing Storms



Nearly a three-vort max phasing resulted in a 944mb low in Quebec February 1-3, 1976



Two-vort max powerful phasing -snowstorm for Toledo, Indiana, Ohio, Kentucky, others. January 9-11, 1977 250mb loop 850mb loop Surface temp and SLP loop



Three-vort max phasing January 7-10, 1978 250mb loop 850mb loop Surface temp and SLP loop This storm is also mentioned in Dean and Bosart (1996) and resulted in a surface low of 964mb in Quebec.



Detroit Snowstorm of 1974



November 29 to December 3, 1974 250mb loop 850mb loop Surface loop

Two-vort max phasing in the Plains occurred before the Great Lakes snowstorm



offshore to Halifax NS February 19, 2004

offshore to Cape Cod/Halifax NS December 26, 2004 250mb vorticity animation 850mb vorticity animation





Two-vort max phasing in the recent years



- Appalachians snowstorm March 30 - April 1, 2003

- New England storm December 5-8, 2003 (GFS 0 hour) 850mb Animation 250mb Animation Surface Animation

- Some less intense phasing in the Charlotte Snowstorm February 25 - 27, 2004

This was complicated, but I think it counts as phasing and a TROWAL in the Northeast US and southeast Canada.

February 28 - March 3, 2005 250mb vorticity animation 850mb vorticity animation

Some type of phasing and surface low possibly in the 940's (mb) range offshore from Maine

March 8-10, 2005 250mb vorticity animation 850mb vorticity animation

April 24, 2005 Great Lakes snowstorm, TROWAL 250mb vorticity animation

October 14-16, 2005 - New England Floods/Non-named subtropical low 850mb vorticity loop 250mb vorticity loop

another 500mb loop 1000mb vorticity/ Sea level pressure loop

Most of the flooding occurred before these two storm systems really phased together. You might even argue for 3 different vort maxes getting involved.

Even more recent storm loops



December 13-16, 2005 500mb vorticity loop 850mb vorticity loop 850mb wind speed loop 250mb vorticity loop Surface Analysis loop

Two upper vort maxes sort of combined in the Great Plains, then a upper vort max/surface low generated on the Gulf Coast and moved northeast, sort of merging with the other low .



January 12-15, 2006 500mb vorticity loop 850mb vorticity loop 850mb wind speed loop 250mb vorticity loop Surface Analysis loop Tropopause Pressure

Strong trough amplification and slow phasing, mostly a rain storm, but a pretty good snow storm for a small portion of Massachusetts and New York, with some snowfall in eastern New York, New Jersey and New England.



January 30-February 1, 2006 500mb vorticity loop 850mb vorticity loop 850mb wind speed loop 250mb vorticity loop Surface Analysis loop Tropopause Pressure

Strong trough amplification, development of a strong ocean storm, possibly considered a bomb.



February 3-5, 2006 "Super Bowl Snowstorm" 500mb vorticity loop 850mb vorticity loop 850mb wind speed loop 250mb vorticity loop Surface Analysis loop Tropopause Pressure

Strong trough amplification, development of a strong low that tracked through eastern Kentucky, Ohio, and southern Ontario, possibly considered a phasing system. The storm dumped several inches of snow north of Detroit in the Thumb of Michigan, one day before the Super Bowl, and also hit areas north and east of Lake Huron, like Sudbury, Ontario, pretty hard.



April 2-9, 2006 500mb loop Surface loop Two consecutive large scale phasing systems. On April 3-4, the cold upper low over Hudson Bay joined into a storm system moving through the Midwest and Mid-Atlantic, forming two noreaster type lows. On April 7-8 (and 9th) another cold upper low in northern Ontario acted as a crusher for the storm system that moved from the Plains to the Tennesee Valley to the Southeast.



May 2006 500mb loop Incredible 15-day loop.



October 27-29 2006 500mb loop Ohio Valley/Northeast storm amplification.



November 14-16 2006 500mb loop Oklahoma/Tennessee Valley/Ohio Valley storm amplification.





March 7-9, 2008 - snowstorm from Texas to the Ohio Valley to Canada. Phasing of upper troughs occurred in the Ohio Valley area (loop to be added later)





Other storms with phasing



March '58 East Coast storm. You decide if this is phasing or not. March 18-23, 1958

- OH Floods of 1959, ended up as a 976mb () low pressure in Quebec January 15-17, 1959

- Ash Wednesday Storm. You decide if this is phasing or not. March 4-6, 1962

- It looks like this one really changed a lot in 24 hours March 5-7, 1965

- Snowstorm for Toledo, Indiana, Kentucky November 1-4, 1966

- Snowstorm for Toledo and Detroit March 21-23, 1968 500mb Vort 250mb Vort 850mb Vort Surface

- Interior East Coast/New England Storm March 3-5, 1971

- Strong trough amplification after a New Year's Eve snowstorm in the Chicago area January 1-3, 1979

- Storm system studied by Lai and Bosart (1988) November 17-18, 1980

- Snowstorm for Toledo and Detroit on February 10, 1981 February 10-12, 1981

- Snowstorm for Akron and Columbus April 2-4, 1987

- January 24-26, 1988 - this is exactly 10 years after the midwest blizzard. Loop

- Snowstorm for Toledo and Detroit January 14, 1992 NARR Animation January 14, 1992 NCEP Reanalysis Animation

- Midwest snowstorm January 1-3, 1999

- Storm system studied by Strahl and Smith (2001) November 2-4, 1999

- Infamous snowstorm of 2001 March 4-6, 2001





Some storms listed in Bosart and Gaza (1990)

note: Bosart and Gaza did not consider phasing over the Atlantic Ocean except for one instance



February 1-3, 1976 as mentioned above

January 9-11, 1977 as mentioned above

January 8-10, 1978 as mentioned above

- January 25-26, 1978 as mentioned above

-central Canada August 21-22, 1980

- Northern New England January 6-8, 1981

- phasing in the Ohio Valley, the surface low bombed east of VA/MD and ended up at 955mb somewhere in the North Atlantic March 15-17, 1981

- eastern Quebec August 13-14, 1981

November 14-16, 1982

- Maine/New Brunswick March 29-30, 1983

- Hudson Bay July 4-5, 1983

- Northern Canada August 4-5, 1983

- central Canada October 16-17, 1983

- offshore from Nova Scotia June 3-4, 1984

December 5-6, 1985

November 19-21, 1986

February 22-24, 1987 - East Coast snowstorm





Tropical - Extratropical Connections



October 14-18, 1954: Hurricane Hazel



June 20-24, 1972: Hurricane Agnes



October 28 - November 2, 1991 : the "Perfect Storm"

(Hurricane Grace, Extratropical Storm, Hurricane #8) not only this, but look at the upper level trough that moves through the Plains/Midwest on November 1 !







Dean and Bosart (1996) did a climatology of trough mergers and fractures in the Northern Hemisphere. One interesting thing to note is that they decide to categorize trough mergers (phasing) as either a "classic" type or a "vortex merger" type. The "vortex merger" type is where two or more vort maxes rotate around each other and interact inside a larger closed upper low. The "classic" merger is best shown by all of the examples from Bosart and Gaza (1990)



Examples of Vortex Mergers (not specifically mentioned in the paper)



"Snow Bowl" of 1950: November 23 to 27, 1950 250mb loop 850mb loop Surface temp and SLP loop

The surface low moved through Manitoba, MN, and Lake Superior. Then it re-generated a new surface low on the cold front in NC/VA and rotated it north to PA and west to OH, in a loop, and northward to Ontario.



November 6-8, 1953



-Eastern Ohio snowstorm December 5-7, 1962



-You have just got to watch this 12-day loop. Cut off lows! February 24 - March 7, 1965



- The storm that sunk the lake freighter Daniel J. Morrell Daniel J. Morrell picture on Lake Huron Wikipedia article on Daniel J. Morrell

November 27-30, 1966



Buffalo Blizzard of 1977: January 28-29, 1977 250mb loop 850mb loop Surface loop

Three vort maxes rotated around each other in Eastern Canada. The southern one caused the snow, lake effect snow, and blizzard conditions in the Great Lakes, especially Buffalo and Watertown.



May 5-7 1989 : late(est) season snow in Toledo



October 18-21 1989 : early season snow in IN and IL



Millennium Snowstorm: East Coast Storm December 29 to 31, 2000



NWS - North Platte NE page on blizzards and case studies



References



Robert S. Gaza and Lance F. Bosart "Trough Merger Characteristics over North America," Wea. Forecasting Vol. 5 No. 2 (1990) pp. 314-331

Chung-Chieng Lai and Lance F. Bosart "A Case Study of Trough Merger In Split Westerly Flow," Mon. Wea. Rev. Vol. 116, No. 10, (1988) pp. 1838-1856.

Jennifer L. S. Strahl and Phillip J. Smith "A Diagnostic Study of an Explosively Deepening Extratropical Cyclone and and Associated 500-hPa Trough Merger," Mon. Wea. Rev. Vol. 129 No. 9 (2001) pp. 2310-2328

Devin B. Dean and Lance F. Bosart, "Northern Hemisphere 500-hPa Trough Merger and Fracture: A Climatology and Case Study," Mon. Wea. Rev. Vol. 124 No. 12 (1996) pp. 2644-2671





Several of these storms involved two-vort max phasing, although the airflow interaction with the Rocky Mountains complicates things.





Plains Blizzard of 1949, January 3-5, 1949 250mb loop 850mb loop Surface loop



Dakota Blizzard and Severe Weather Outbreak, March 24-28, 1950. 250mb loop 850mb loop Surface loop This storm broke sea-level pressure records in KS, NE, CO, IA, and SD, lowest pressrure 969.5mb in Sioux Falls SD.



Cut off low March 11-15, 1951



Snowstorm and Severe Weather Outbreak, February 26-28, 1958 250mb loop 850mb loop Surface loop



Blizzard and Tornado Outbreak November 17-19, 1958 250mb loop 850mb loop Surface loop



Plains Blizzard of 1966, March 2-5, 1966



Upper Midwest Snowstorm, April 7-11, 1973



Plains and Upper Midwest Blizzard of 1975, January 10-12, 1975 250mb loop 850mb loop Surface loop





Edmund Fitzgerald Storm/Blizzard, November 9-11, 1975



Chicago Blizzard of '79 January 12-14, 1979 NARR Animation January 12-14, 1979 NCEP Reanalysis Animation 250 loop 850 loop Surface loop

Near the end of this animation, you can see a second vort max moving into the system, traveling through Manitoba and Minnesota.

January 14, 1979 00z 300mb wind speed



October 28 - November 2, 1991

Minnesota Blizzard/snowstorm October 31 - November 1



Plains and Upper Midwest Blizzard of 1996, January 17-20, 1996



Blizzard and Severe Weather, November 9-11, 1998. This storm broke sea-level pressure records in Minnesota and reached a low of about 972mb in Minnesota.





Recent Plains Storms



Northern Plains Blizzard, ice storm, and tornadoes/severe weather November 26-28, 2005 - 500mb Loop 250mb Loop 850mb Loop Surface Analysis Loop



April 11, 2008 - strong trough amplification in the central Plains



The Great Christmas Storm of 2009



Recent Midwest Storms

December 22-23, 2007 - two upper lows combined in the Upper Midwest

500mb plot from 12z December 23











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