May 1-14, 2005 Pattern Discussion

[donsutherland1]

Last week’s discussion raised a number of issues of what one might expect for the April 24-May 7, 2005 period.

• April 23-30 will likely see readings average below normal. Late April 22 and April 23 should bring a soaking rain. Boston, New York, Philadelphia, and Washington, DC will likely receive 0.50”-1.50” rain. A much cooler air mass will overspread the region on Sunday. The potential exists for low temperatures to fall to 43° or below in Boston, 45° or below in NYC, and 47° or below in Washington, DC on one or more days next week. April 26-27 could bring additional rain followed by a new push of colder air.

April 23-28 Temperature departures:
Boston: +0.3° Lowest: 41°, April 25
New York City: -1.3° Lowest: 40°, April 25
Washington, DC: -2.8° Lowest: 40°, April 25

Rainfall:
Boston: April 23-24: 0.79”; April 27: 0.32”
New York City: April 23-24: 1.15”; April 27: 0.49”
Washington, DC: April 22-23: 0.48”

• April 23-25 will see a series of storms bring snow and rain to the Midwest/Great Lakes Region. Detroit could pick up 3” or more of snow. Even Chicago could see a trace of snow. April 23-30 should experience much below normal temperatures. Both Detroit and Chicago could see temperatures fall below 32°, especially in the April 24-25 timeframe and then perhaps on April 28.

April 23-28 Temperature departures:
Chicago: -4.3° Lowest: 33°, April 24
Detroit: -8.2° Lowest: 32°, April 24

Snowfall:
Ann Arbor: 5.5”
Chicago: Trace (4/23)
Cleveland: 12.4”
Detroit: 4.4”
North Royalton/Broadview Heights, OH: 25.3”
Northeast Clarkson, MI: 16.5”

• April 24-27 will experience below normal temperatures in the Central Plains states. Some moderation is likely during the April 28-30 period. However, April 29-30 could bring rain to parts of the region.

April 24-27 Temperature departures:
Kansas City: -11.3°
Omaha: -7.7°

Light rain fell on April 29 in Kansas City. However, there was little or nor warming on April 28-29.

• After a very warm start to the weekend with the temperature likely rising into the 70s in Seattle on Saturday, cooler air should return. April 25 and then again on April 28-29, there could be rain in the Pacific Northwest.

The weekend (April 23-24) saw temperatures in the middle 60s in Seattle. Some rain fell during the April 28-29 period.

• April 24-25 will likely be somewhat cooler than normal in Los Angeles. Some showers are possible. Midweek, April 26-28 will probably be milder with readings running near or somewhat above normal. April 28 could bring showers courtesy of another storm affecting the West Coast, particularly the Pacific Northwest along with cooler readings.

The April 24-25 period saw readings in Downtown Los Angeles average 4° below normal. The cool weather continued afterward, though April 26 saw a high temperature of 73°. On April 28, a daily record rainfall of 1.02” was recorded in Downtown Los Angeles.

The May 1-14, 2005 Ideas:

The first two weeks of May should witness several large-scale developments:

• The strong block that peaked with an NAO of –2.225 on April 27 should give way to a positive NAO during the May 1-10 period, and probably during the first half of that period. At the same time, the negative PNA should trend positive. An NAO+/PNA+ configuration often leads to cool weather in the eastern United States.

• The Southern Jet should remain active. As a result, the potential exists for wetter than normal weather, especially across parts of the Plains/Midwest to the Mid-Atlantic/Southeast regions.

• Per the MJO, some ridging should commence after May 5. However, it could be briefly dented after May 10 before more important ridging in the East takes hold around or just after mid-month.

As a result, it appears that the May 1-14 period could experience the following conditions:

• Northeast/Mid-Atlantic: A fresh unseasonably cold air mass could move into the region on Sunday night. Before then, the region could experience severe thunderstorms on April 30. The potential exists for low temperatures to fall to 43° or below in Boston, 45° or below in NYC, and 47° or below in Washington, DC on one or more days next week. Slow warming will likely commence on May 6. The May 7-10 period could experience readings that are somewhat above normal before cooler air returns.

• Chicago and Detroit will likely experience a fresh surge of unseasonably cold air for the May 1-4 period. It is possible that both cities could see at least one minimum temperature that is below 40°. Noticeable warming will likely commence on May 5. The May 6-10 period could see high temperatures rebound into the 60s and perhaps 70s.

• In the Central Plains, generally cool conditions are likely to prevail through May 3. Afterward, a significant warmup is likely to commence. By May 6, Kansas City and Omaha could see temperatures in the 70s. The May 8-12 period could see at least one day reach 80° or above in both cities.

• May 1-7 will likely see warmth return to Seattle. May 5 could experience some showers. May 3-10 will likely see temperatures average above normal.

• May 1-2 will likely see somewhat below normal readings persist in Los Angeles. Afterward, the May 3-5 period should experience near normal or somewhat above normal readings. Temporary cooling could occur around May 6 or 7 before readings return to near normal readings shortly afterward. Precipitation through the entire period should be low.

A Look Back: The Unseasonable Cold of May 1895

The May 1895 edition of Monthly Weather Review wrote of the weather in New York State, “The weather was remarkable for great ranges and variability of temperature.”1 The same held true for much of the Midwest and the East Coast.

On May 10, 1895, the temperature soared to 90° in New York City’s Central Park2 and 86°3 at the Weather Bureau. “Whether it was because people in general are still too warmly dressed to stand hot weather with comfort, or whether it was because they are not used to forty-eight hours’ continuous hot weather so early in the season…the fact remains that yesterday was a very trying day,” the May 11, 1895 edition of The New York Times reported. 4 But that would change quickly.

Even as the mercury bubbled in New York City and along the East Coast, it was snowing in South Dakota’s Black Hills. Four inches were reported there on May 10 with heavy frosts covering parts of Iowa, South Dakota and Nebraska. 5 A day later, even as the temperature reached the lower 80s in New York City for yet another day6, colder air was working steadily south and east. The night of May 11 saw an inch of snow fall at Rome, New York.7

Even as the stage was being set for a record cold outbreak in the East, a snowstorm blanketed parts of the Great Lakes Region and Ohio Valley on May 12-14. In Michigan, some places picked up a significant snowfall. “Frederick reports nine to ten inches of snow; Ossime three inches and still snowing; Lewiston, eight inches and still snowing; Menominee, four inches, with all gardens and many fruit and shade trees truined, and Mainisteo, two inches,” The New York Times reported8, “At Alpena the ground is covered to the depth of two or three inches with snow… At Gaylord a northeast snowstorm prevailed during the night and the snow was ten inches deep on the level this morning [May 13].” On May 13, Valparaiso, IN experienced snow that “fell at intervals” along with “a hard wind.” 9 At Malvern, Ohio, it was reported that “considerable snow fell here this morning” of the 14th. 10 In addition, the temperature at Malvern fell to 26°.11 The cold spell at Malvern was described as the worst late-season one in the Sandy Valley since that of June 5, 1859 12 of which the Cincinnati [i]Commercial wrote: The effect of the remarkable frost of Saturday night is disastrous. Incalculable damage has been done to vegetables, fruit and grain. The old settlers say that in 1815 there was a terrible frost here in June, but since that time no such phenomenon has been so serious as to have been specially observed until now. 13 Even Oakland, MD picked up seven inches of snow. 14

On May 13, the temperature plunged from 67° to 39° in New York City.15 That began a stretch of 10 consecutive days where the temperature would rise no higher than the 60s with minimum temperatures in the 40s:16

New York City: May 13-22 Temperature Record:
May 13 67-39 (record low still stands)
May 14 54-48
May 15 58-44
May 16 62-45
May 17 62-43
May 18 61-48
May 19 57-49
May 20 67-49
May 21 54-47
May 22 65-45 (record low still stands)

From Concord, NH it was reported on May 14, “The cold wave last night, followed so closely on the phenomenally hot weather of last week, did great damage to crops and vegetation…”17 At Derry, NH the temperature fell to as low as 20° and at Hanover the ground was frozen “in some places half an inch deep.” 18

A reinforcing shot of cold air that arrived on May 16, 19 kept readings much below normal through May 23. On May 17, the thermometer registered 28° at New Milford, CT20 and parts of Long Island shivered under 24° temperatures with ice forming in “many places.”21 At Deer Park, MD, the temperature fell to 20° on both May 18 and 22.22 On May 21, the temperature bottomed out at 25° at Rochester, NY and “The low lands presented the appearance of Winter” with ice reported “an inch thick.”23 On May 21, Norwalk, OH had a minimum temperature of 19°.24

All said, Maryland witnessed killing frosts on May 13-15, 17, 22, and 23; New England suffered under hard frosts on May 14, 17, 19, 22 and 23 with some areas picking up a trace of snow on the 14th and 16th; South Carolina experienced light frosts on May 13, 15, and 23.25

North America was not alone in witnessing exceptionally cold weather. On May 16, “A dispatch from Broadstairs, Isle of Thanet, County of Kent” in Britain reported “a gale, accompanied by snow and hail” and there were reports of “snowstorms and minor wrecks” on England’s east coast.26 On May 18, it was reported from Italy that “Bitter cold weather, accompanied by snow, prevails in Central Italy” and “Several of the Swiss mountain railways have been compelled to suspend their recently-opened Summer services owing to the heavy snowfall. The carriage roads and the passes are blocked with drifts.”27

Finally, as sharp as the cold was, equally intense heat returned to the East in the closing days of May. On May 30-31, the temperature soared to 90° or above in New York City28 and to or just above 100° in parts of the East.29

Endnotes:

1. Monthly Weather Review,” May 1895, p.166.
2. Utah Climate Center.
3. “May Record Not Broken,” The New York Times, May 11, 1895.
4. “May Record Not Broken,” The New York Times, May 11, 1895.
5. “Winter Weather in the West,” The New York Times, May 12, 1895.
6. Utah Climate Center.
7. “Heavy Damage By Frost,” The New York Times, May 14, 1895.
8. “Snow in Michigan,” The New York Times, May 14, 1895.
9. “Ohio Crops Damaged,” The New York Times, May 14, 1895.
10. “More Snow in Ohio,” The New York Times, May 15, 1895.
11. “More Snow in Ohio,” The New York Times, May 15, 1895.
12. “More Snow in Ohio,” The New York Times, May 15, 1895.
13. “The June Frosts,” The New York Times, June 9, 1859.
14. Monthly Weather Review,” May 1895, p.165.
15. Utah Climate Center.
16. Utah Climate Center.
17. “New England Suffers,” The New York Times, May 15, 1895.
18. “New England Suffers,” The New York Times, May 15, 1895.
19. Monthly Weather Review,” May 1895, p.167.
20. “Connecticut Fruit Killed,” The New York Times, May 18, 1895.
21. “Damage to Garden Truck,” The New York Times, May 18, 1895.
22. Monthly Weather Review,” May 1895, p.165.
23. “A Very Destructive Frost,” The New York Times, May 22, 1895.
24. Monthly Weather Review,” May 1895, p.167.
25. Monthly Weather Review,” May 1895, pp.165-167.
26. “Gales and Cold in Europe,” The New York Times, May 17, 1895.
27. “Europe’s Wintry Weather,” The New York Times, May 19, 1895.
28. Utah Climate Center.
29. Monthly Weather Review,” May 1895, pp.165-167.