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Berks Winter Cast

Case Study Of Top 10 Winter Storms

HISTORICAL WINTER STORMS FOR THE NORTHWEST SUBURBS IN SOUTHEAST PENNSYLVANIA


- A Case Study of the Top 10 Storms (3 way tie for 8th place, 12 Total Storms)
- Ranking Based On Accumulation Out of Reading, PA


Conclusions

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Here was see the track of our storms as can be seen there is a zone of where to be, inside Hatteras and NE to the Delmarva where an E/NE track becomes more favorable.

In terms of Miller A vs Miller B storms



Out of 11 total storms 7 were Miller B’s and 4 were Miller A’s so the nod would appear to go to coastal redevelopments and the fact that in the top 4 storms it’s a 50/50 split shows no preference for which is more potent.

When looking closer at the tracks and separating the Miller A’s and B’s one can see some possible trends…

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Miller A’s look to need to track closer to the coast then their brethren, and here its 50/50 split of a NE track vs. an E/NE track, although it should be noted that the 2 that went E/NE are in the top 3 in our study in terms of snowfall output.

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Miller B's on the other hand appear to be further out to sea and most have a E/NE trend that begins off the coast of the Delmarva before NJ

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Looking at the 850 tracks, a few laws are indeed in place, track needs to be south or east of I-95 corridor, the preferred track appears to be almost due E off the Delmarva.

When looking at storm type, open, open to closed, or closed off through and through do not seem to matter, all three are spread out equally in the study.



Looking at the high pressures the strength for zone 2 appears to need to be higher but due to a distance being further away that would make sense, Zone 1 highs have preferred track staying in SE Canada and north of NE to avoid suppression.




When looking at the ENSO state for historic storms, a lot of people put emphasis on a weak El Nino for being prime, but looking at the study only one storm, PDI fits the bill, people often also shy away from moderate or strong El Nino’s but a whopping 6 of 11 storms fall into these to categories. A lot of people also take exception with La Nina stating that the Blizzard of 96 was more the exception not the rule… Which is not the case here, 61’ was also a Weak Nina and earlier in the century moderate La Nina’s produced two of our storms… The only state that is not covered is a strong Nina which looks to be a state to shy away from… Neutral also isn’t too enticing even though 94 falls into this state, remember it took 2 moderate storms on top of each other to achieve Case Study status. A signal either way appears to be needed for historic storms but the nod goes to El Nino with more storms.




The North Atlantic Oscillation is also a hot topic for forecasters when looking for classic winter storms, and it is true that the majority of storms look to need a negative NAO in place before hand as 7 of the storms were in this study, in terms of trend a rising NAO from negative also looks to be best, 5 of the 7 saw changes to positive or rises to neutral (96, PDI, 93’, 83 and 58a) the remaining 258b and 78 saw no change from negative. But the opposite is possible as shown by PD II or in the cases of 94 or 61 a positive can stay positive or a neutral can stay neutral.



When looking at timing February is where its at its max, with 6 of our 12 storms, only 2 in January and March, and one at the end of December
 


The Blizzard of 96, or as others call it “The Storm of the Century”, was most likely the best set of circumstances for the entire region to receive extreme snowfall… In this study it is by far the heaviest snowfall and the only one to reach the 30” mark, a mark that was achieved in numerous locations in SE PA…

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It also one of only 4 Miller A’s in our top 10 snowfall cases, a perfect track combined with slow movement was key here in the excessive snowfall amounts.

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Explosive development took place at the perfect possible location as well as seen above between 1/8 00z and 12z on the 8th, the extremely slow speed of the surface low from the NC coast to the mouth of the Delaware Bay was also the prime location or what later I go on to describe as “The G- Spot”, spending the most amount of time in this zone while also experiencing explosive development here, more so than any other storm, led to the extreme snows for SE PA. The overall average pressure of this storm was 975mb, surprisingly good for only 5th lowest in this case study.

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The track of the 850 low was also about as perfect as you can get for the area… closed off and well south of the area upon entry, tracking along the VA/NC border, and then moving east northeast across SE VA and the very southern tip of the Delmarva Peninsula and then continuing out to sea. The axis of heaviest snow was about 150-200 miles NW of this track and ran parallel to it… right into the heart of SE PA.



High pressure strength and location is one of the most underrated aspects of winter storms, the anticyclone set up in the Blizzard of 96’ was about as classic as one can ask for, a true Banana High. Two separate high pressure systems can be seen, the far western high originated in what I call zone 2 for our winter storms, this location gets the secondary rating, due to the fact that highs originating in Zone 1 (in SE Canada) are usually more prevalent and generally speaking more important. This high started as 1040 plus and remained well over 1020mb its entire track southward into the Gulf of Mexico… The average strength of the zone 2 high was at 1038. The zone 1 high coming out the Great Lakes and then NE into Canada was at a lower strength an average of 1031 for its course, but was more than sufficient due to its prime location and over 1020mb strength.

Supplemental
- Occurred during a weak La Nina
- NAO was negative before storm, went to positive signal after storm, storm initiated regime change



Presidents Day Storm II, was the second major storm to occur on this holiday, PDI had occurred 24 years earlier and will be covered later in this study… PDII coming in 2nd for the region wasn’t a very impressive storm on paper; it was a situation where an open wave attacked a strong cold high… A true cold core storm, in every sense of the phrase. It still packed quite a punch.

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A relatively mild storm in over all strength, the track was more than acceptable, with a coastal track similar to that of 96’s just a much faster forward speed, this storm was a Miller B type storm and featured an energy transfer from the initial low tracking towards the eastern Ohio Valley to a coastal low that had formed at the southern NC coast. The avg. pressure of this storm was a very modest 1009mb the highest of any (single storm) seen in this study.

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The 850 low track seen with this storm, again shows this energy transfer that we seen in Miller “B” type storms, the initial 850 low was tracking through the Ohio Valley, and then jumped to southern VA, crossing over the Delmarva E/NE out to sea… The axis of heaviest snow is seen on the Mason Dixon line and then jumping northeast once reaching SE PA, this storm represents the best case scenario for a Miller B system for our area.



As said before this storm is highlighted by the high pressure system that was in place, starting at 1040mb and then increasing to 1044mb right as the storm got cranking, during the storms overall course the anti cyclone features an average strength at 1036, which does not sound that high, the but being at 1040 or higher for the storms first 24 hours was key here… track was perfect for the NW burbs, but in places closer to the I-95 corridor, the eastward track eventually led the high pressure to go offshore and moderate faster which led to snow sleet mix in those locations.

Supplemental
- This storm occurred during a moderate El Nino winter, it was however an El Nino that was on the decline.
- In regards to the NAO this storm is an anomaly at #2 as it was in a positive state and went to negative at the time of the storm, which is usually the opposite of the ideal NAO situation.
 


The Megalopolis Blizzard of 83, is a storm that is highly regarded by many snowstorm lovers in the I-95 corridor, with a large 20”+ band of snow that started in north central VA, up through DC, Baltimore, Philly and NYC, only Boston and areas of New England didn’t get the full wrath of this storm. This storm was another classic Miller A type storm.

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Again not a stalling storm, it moved along up the coast at a healthy pace but not too fast to be sure, the storm strengthened steadily but again there was no explosive development, the average low pressure was 1000 mb for its trip, which is good for 6th best on the list. The track again was a text book one for heavy snows in SE PA, west of Cape Hatteras, close to the Delmarva but just off coast and then a turn to the E/NE as apposed to just NE.

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850 low again is another example of a great track, crossing over the southern Delmarva Pen., before turning E/NE. Axis of heaviest snow parallel to this track 125 miles NW.



High Pressure was a true classic, featuring only a zone 1 high, it started at 1036 and increased to 1040 mb at the height of the storm, avg pressure of this high was 1037mb, but the track here was the key to this storms success, in SE Canada but never moving into New England, or worse into the Atlantic.

Supplemental
- This storm occurred during one of the 2 monster El Nino’s in fact the 2nd strongest on record
- NAO status…Strong negative status pre storm, moderated during the storm but remained in negative territory



Talk about a snow lovers dream coming in #4 is the Christmas Day Blizzard of 1909, the storm was a classic Miller B storm with a primary low in the Midwest transferring to a coastal low on the SC coast. It is the last single* storm to dump 20” or more on Reading.

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The storms fury was mainly felt hardest from central DE northward into southeast PA

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Although there is a limited amount of information regarding this storm, it started with a primary low of 1000 mb in the Ohio Valley transferring to a coastal low on the Northern SC coast, this low experienced explosive development, on its track inside Hatteras and east of the Delmarva, this N/NE track changed to a NE one once it reached the mouth of Delaware Bay. Avg. pressure was 988mb, 2nd lowest in this study, there is limited data however.

No 850 low information.

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Though High Pressure information is limited, with the data that is here this storm again is anomalous, there was a pre-storm 1020 low over the Mid Atlantic, this high pressure then moved eastward out to sea last data on it was that it was sub 1020. Hardly an ideal strength or location for an anti cyclone, there also was a quasi zone 2 high pressure with info indicating it tracked from CO southeastward towards Houston. Avg. strength was 1030mb… It has been raised by some that there might have been influence from another high pressure but there is no documentation of this.

Supplemental
- ENSO was a moderate La Nina
- No NAO data
 


The last storm in this study to drop 20” on Reading was actually two storms of the course of three days, the storms were both very modest in strength and bother were Miller B redevelopment cases.

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The best this storm(s) had to offer was in spotty locations across PA NJ, NY CT and more extensively in MA.

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Storm one tracked across the MO/AR border into the TN/KY border to WV before redeveloping just to the east of the southern tip of the Delmarva this storm tracked almost due east, this storm was the stronger of the two but never underwent explosive development and maintained a modest average of 1006mb. Storm 2 originated in the Gulf of Mexico, tracked across the Gulf states to the base of the Appalachians, redevelopment took place on the SC coast two days after the 1st storm was wreaking havoc to the north, this storm also never underwent explosive development and barely intensified during its trek which was west of Hatteras, and the E/NE after reaching coastal Delmarva, avg pressure… tied for the weakest at 1009mb.

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850 low here was much further north that any others within this study, tracking across WV through north central MD and across southern NJ, axis of heaviest snow was about 90 miles north of this track and again spotty due to the 2 storm nature, localized heavy snowfall occurred.



High pressure here might have been key, originating zone 2 it tracked across ther northern US into SE Canada starting first as a decent pressure of 1031 but increasing to 1040 at the storms height. Average pressure 1036mb, this is another case of an open wave attacking an arctic high.

Supplemental
- ENSO An El Nino that had been in pace for 3 years had reverted to a neutral state around the time of the storm.
- NAO status was another anomaly as it had been in a long positive state since NOV, making this winter anomalous as a whole due to it ferocity while in a positive state. There was no change in NAO at the time of the storm




Going from one two storm combo to another… The blizzards of 58 were separated by weeks… the first one comes in at #6 on the list, and was a Miller A Storm out of the Rockies along Gulf coast up the eastern Seaboard.

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This storm begins a trend in the study as we see a shift to heavier snows inland as apposed at to being along the coast, heaviest snow with the Blizzard of 58 A (or,1) was from northern MD into south central PA un into central NE.

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Although this storm never went explosive development it did strengthen at a healthy clip and had an avg. pressure of 989mb 3rd best on the list, this storm was a another classic Miller A but the track was a bit closer to the coast so heaviest snows were further inland, the storm one in ME stalled and even did one of the famous loops, (ironically so did 58 B (2)).

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850 low here basically followed the same track as the surface low pressure, axis of heaviest snow was 150-200 miles west of the track.



High pressure here was key but not for the normal reasons, it originated in zone 2 and was the sole cold source provider as there was no zone 1 high, pressure was decent at 1034mb, but being so far removed it most likely had the impact of allowing changeover’s in most cases until well inland even past Berks County.

Supplemental
- ENSO was a moderate El Nino that was once close to strong
- NAO here had been in a long negative state since Jan. it dipped further negative just before storm and moderated to near neutral at and after storm
 


One of many big storms this winter the Blizzard of Feb 61’ comes at #7 and was a classic Miller B storm, but with track closer to the coast, heavier snow was well inland. This is the only storm from the 60’s in this study.

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Heavy snows occurred most everywhere but the heaviest were in central NY.

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Track here was closer to the coast that in most storms, especially when compared to other Miller B cases in this study… Also for a Miller B it tracked NE as apposed to E/NE for a longer time that other “B”’s in this study, not making the Eastward shift until reaching the NJ coast. This storm did under-go explosive development but barely made that classification, average pressure here was 1004, most of the development occurred at the height of the storm for the region, may have come to late, other wise this storm could have ended up higher on this list.

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Again another fairly north 850 low track, originally in northern Ohio as the transfer occurred so did a track of the 850 from western VA across central Delmarva and east out to sea. Axis of heaviest snow was much further north in this case 350 miles or so north.



With relatively “bad” track of the low’s the higher was very strong at an avg. of 1043 tied for 2nd highest in this study, and even looped southwestward once it reached coastal Canada.

Supplemental
- ENSO was neutral after a weak La Nina had ended recently
- NAO state was by and large neutral this whole winter and didn’t feature strong positive or negative signals, as too was the case for this storm




The #8 storm ends up being a three way tie between storms (in terms of snowfall in KRDG)… The first of which brings up back to 1958 and what a monster this storm was for parts of PA very close to Reading… The Blizzard of 58 B (or 2) is the latest of all storms in our case study… It was a Miller B storm and just with the Feb Blizzard earlier that year; this storm also features a “stall and loop” segment just a bit further south on this 2nd storm.

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The March Blizzard of 58’ features the most extreme snowfall but it was confined to a narrow band and was VERY elevation dependant… The storm has the distinction of setting the snowfall record for a PA location from one storm, that location was Morgantown, PA and was a staggering 50” Reading is just 10 miles north and received snowfall amount of 16”, but some of the hillier locations received the 20 and 40” amounts. This storm shows what late season storms are capable of, but also how complex they are.

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Track here was a Miller B although it wasn’t your standard Miller B transfer, it started out as your normal southern storm cutting across TX to AL, but here at the base of the Appalachians the storm cut northward and very quickly transferred to a coastal storm taking shape just off shore from Wilmington, NC… this coastal low was non-explosive but again featured a steady strengthening process, tracking inside Hatteras, off the Delmarva and into southern NE where the stall and loop occurred. The low averaged strength of 991mb good for a ranking of 4th.

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850 low track was far enough out to put the axis of heaviest snow right into SE PA



High pressure systems with this storm were quite weak in comparison with other storms in this study, the location wasn’t completely unfavorable as it was in close to the storm and not east of NE… A zone 1 type with an average of 1031 when combined with a stronger 1039 mb high in the Hudson Bay in Canada. Still it wasn’t quite strong enough though for coastal locations which saw a changeover to rain, even in Reading and surrounding areas it is known for being a massive sleet storm more than a snowstorm.

Supplemental

ENSO- The strong El Nino was fading at this point but still was Strong to Moderate.
NAO- a Negative NAO became even more negative during and after event.
 


Part two of the three way tie for 8th place is the Blizzard of 78’ which will bring back fond memories for New Englanders but it did provide a decent hit to areas to the south and west.

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Heaviest snows were located in northern NJ and spread into NE where the heaviest snow fell.

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The Blizzard of 78’ was a Miller B of classic fashion for areas north and east of NYC, a primary low coming out of the Great Lakes region with a transfer to a coastal low off the shore of the Outer Banks, this coastal was fairly far out to sea and tracked almost due north until just south of Long Island where a turn to the E/NE took hold, this insured a memorable storm for NE. Although the average low was 1007 mb the coastal started at 1014 and ended peaked at 984 SE of NYC, so it was explosive development.

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850 low was about as unorthodox as it can be at least as initially with a track across Lake Superior southeast ward to Lake Ontario. As the coastal took over again we see the axis of heaviest snow begin as the turn to the E/NE began. A New England special for sure.



The high pressure systems seen with storm are about as complex and as strong as one could expect to ever possibly see. With 3 separate anticyclones one originating from zone 2 maintained over a 1050mb average… at 1052mb. There were two separate zone 1 high’s they averaged at 1042mb.

Supplemental

- ENSO was an extended moderate El Nino
- A negative NAO developed before the storm and sank even more negative during and after




Coming in 3rd in our 8th place tie is the first Presidents Day Blizzard or as we have come to call it since the 2nd one PDI. This was also a classic Miller B storm and more impressive by the numbers than its younger brother.

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The impact of PDI however was felt at least mainly to the south of our region, across the northern Chesapeake Bay area.

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This Miller B was however more explosive and after starting at 1018mb it still ended with 1008mb average, the surface low track however did turn easterly more quickly than seen with other storms in this study, hence the southern snowfall.

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The 850 low here was heading NE and then almost due east quicker than seen with other storms, axis of heaviest snow is seen about 200 miles parallel to the track and began after the coastal really got going and as the 850 low met the coastal areas near Virginia Beach.



The high pressure system seen here was quite strong and far south which could have added more reason for the suppressed southern track, a zone 1 high with an average of 1043mb.

Supplemental

- ENSO Here we had everyone’s favorite of a weak El Nino
- NAO had been negative for 1 month before turning positive after the storm
 
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Number 9 was the blizzard of 25, which occurred right after the New Year. And was an East Central PA special, no other information is available at this time about this storm other than the fact that occurred during a moderate La Nina.



Finishing out our study of storms is the Superstorm of 93’ or as a select few say its was the first “Storm of the Century” until it was replaced 3 years later by the Blizzard of 96’ with that title. And it truly was a massive storm and deserves the title. It is the definition of the strongest Miller A as well.

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Heaviest snow was seen well inland over the Appalachians with spotty 30”+ amounts all up the spine of the chain. Mixing occurred all over the place in coastal regions all the way up to the I-95 corridor, and up the Mountains themselves.

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The mixing could be expected though, as the track was right over the coastal plain, most storms with this track would never even make this list but a number of factors helped make this one of the great storms, its strength for one was incredible with record lows. The average seen here is an amazingly low 975mb and although there was explosive development it was so early it didn’t matter. What mattered here was the strength of the storm in general.

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The 850 low with this storm was well inland tracking over Philadelphia and NE… Way to close for comfort, the axis of heaviest snow again ran parallel by about 150 miles or so.



High Pressures seen here were impressive in terms of strength and track for how late in the season it was. Zone 2’s high tracked out of central Canada into the north central plains averaged 1038mb. Zone 1’s high started out in SE Canada and tracked eastward into the Atlantic this helped fuel the mixing issues, average high here was 1034mb.

Supplemental
- ENSO During a 3 year El Nino had peaked in early 92 was headed toward a seconday peak in the spring of 93, good for Moderate status
- NAO went negative a month before storm and rose sharply to positive during and after the storm.