Prepare ye for winter - if you can. Depending on whom you listen to, it may be mild, harsh, both or neither.

The federal government's official but tentative outlook prepared by the National Oceanic and Atmospheric Administration (NOAA) calls for a "colder then normal winter" here abouts.

Irving P. Krick, internationally known private meteorological consultant based in Palm Springs, Calif., on the contrary, says he sees a generally "mild winter" ahead for the Washington area.

Gordon Barnes, WTOP-TV weatherman who also operates a private weather consultancy, goes along more with the government's cooler-than-normal scenario. As early as last July, he forecast that temperatures should average 15 percent below normal for the Oct. 1-to-March 31 period, which is cold but not as severe as last winter's record-breaking cold.

The Old Farmer's Almanac, published in Dublin, N.H., says the winter here should be near or slightly above normal, except for February which will probably be colder then normal.

The Hagers-Town Almanack, published in nearby Hagerstown, Md., on the other hand, says in its "Conjecture of the Weather" that February, along with December, should be average, while November, January and March should be colder than normal.

Noted seer Jeane Dixon has something to say about the weather, too. Asked by The Washington Post for her forecast, she said the winter as a whole should not be as severe as last winter's and there will be no major snow storms.

Regardless of how the winter turns out, it will be no more than a speck on the meteorological charts, a statistical jot absorbed into the volumes of historical weather data that climatologists use to map patterns of the past and set the probabilities for the future.

And there is almost as much disagreement among the experts about the causes and probabilities of long range climate trends as there is about whether it will rain next Tuesday.

At a global level, there are two almost diametrically opposed schools of thought on future climate trends.

One school, exemplified by senior research climatologist J. Murray Mitchell Jr. of NOAA, contends that a general worldwide cooling trend that started 30 to 40 years ago may be reversing itself.

Enormous increases of carbon dioxide in the air caused by the burning of oil, coal and other fossil fuels appear to be overriding the natural cooling trend, Mitchell says, "and a warming trend should start taking off like a scalded cat by the end of the century."

In contrast followers of Reid A. Bryson, director of the Institute for Environmental Studies at the University of Wisconsin, contend the cooling trend is continuing despite the increased carbon Dioxide, and the northern hemisphere may soon plunge back into a "little ice age" reminiscent of the 1600-1850 era of Europe and North America.

Either eventually, according to their proponents, could have devasting effects on present world agriculture, trade and economic patterns.

In the Washington area, the climate has generally paralleled hemisperic trends for the last century, showing a gradual but definite upward movement in average temperatures.

The much debated cooling trend that started in some parts of the world in the 1940s and 1950s, however, shows up as only a slight dip in the annual average temperatures during the 1960s. The dip has since been virtually eliminated by the record high temperature averages of the 1970s.

Mitchell says that is because still another phenomenon - the "urban heat island" - has tended to neutralize much of the cooling trend with the artificial heating influences unique to densely populated cities with their power plants, air conditioning systems, automobile heat emissions and vast expanses of heat-absorbing concrete and metal.

A 1961 study by Mitchell comparing Washington's increasingly urbanized temperature with temperature averages at rural points in eastern Maryland since 1895 shows that Washington has been warming up at a faster rate than the surrounding countryside.

Since 1871, when the National Weather Service began keeping records for Washington, the average annual temperature has generally been increasing. It averaged less than 55 degrees for the years prior to the turn of the century, crept up to 55.71 degrees for the period from 1900 to 1939, and has averaged 58.58 degrees since 1940.

The temperature reaches 90 degrees more often in the summer and drops to freezing less often in winter now than in the past.

In the 19th century and early 20th century, the temperature frequently fell below zero in the winter. The last time the thermometer hit zero was 1936. During last winter's freakishly cold spell, the temperature fell to 2 degrees above zero on Jan. 17, a record low for the date and the lowest temperature since a reading of one degree on Dec. 21, 1942.

The winter also set a record for the longest string of consecutive days that the temperature fell to 32 degrees of lower - 48 days, from Dec. 27 through Feb. 12.

But Weather Service climatologists stress the freakish nature of the winter and said it is not likely to be repeated any time soon. The persistent cold was caused by frigid upper air currents from the west whose pattern over the Washington area remained steady instead of shifting periodically and giving way to warmer, more southerly air, as is more typical.

Historical weather records also show that Washington is receiving slightly less precipitation than it used to. Precipitation has declined from an average of about 43 inches per year prior to 1900 to about 40 inches each year from 1937 to the present.

Despite the decline, both the local water table and the flow rate of the Potomac River do not appear affected, according to records of the U.S. Geological Survey. Though the water table and river flow have fluctuated widely in response to short term wet and dry periods over the years, there is no discernible downward trend in either.

Records before the official commencement of National Weather Service data for Washington in 1871 are hard to find and of questioned reliability.

But a compilation of temperature and precipitation averages gleaned from old Naval Observatory, Smithsonian Institution, National Archives and private records dating back to 1817 suggests that Washington's weather in the first half of the 19th century, rather than being part of the current drier-warmer trend, was highly erratic with dramatic extremes of heat, cold, drought and heavy rains.

Some highlights of the pre-1871 period:

The year 1836 was colder than any year in the modern Weather Service record book. The temperature averaged 51.4 degrees for the year, well below the modern record low of 52.2 degrees set in 1875 and 1904.

At the other extreme, the temperature average jumped to 58.4 degrees in 1822, not to be matched or exceeded until 1949, when the temperature averaged 59.0 degrees as part of the current warming trend. The all-time high is 59.4 degrees set in 1975.

The year 1826 was drier than any in the modern record period. A total of only 18.79 inches of precipitation was measured, compared to the modern record low of 21.66 inches in 1930. Normal annual precipitation is now 38.89 inches.

The summer of 1846 was a sizzler that makes this past summer's discomfort seem mild by comparison. For 18 consecutive days in July, 1846, the temperature hit 90 degrees or higher. It exceeded 100 degrees on four of those days, peaking on July 13 at 106 degrees. On July 22, the temperature never fell below 83 degrees at night. It pushed to 88 by 4 a.m., stood at 90 degrees at 9 a.m. and peaked at 99 at 4 p.m.

The 83-degree nighttime low reading beats the modern record of 80 (set this summer). The 18 consecutive days of 90-plus heat ties the modern record set in 1872. (Last summer, there were never more than 10 consecutive days of 90-plus heat, and the termometer reached 100 only once.) The 106-degrees reading on July 13, 1846, ties the modern single-day high set on July 20, 1930.

The winters were equally vicious. According to observatory records, on Jan. 29, 1855, the temperature began dropping quickly in the afternoon and was below freezing by 6 p.m. Except for a few brief hours four days later on Feb. 2 when the thermometer crept to 35 degrees, it stayed below the 32-degree freezing mark for 13 straight days. The modern record is nine days of sub-freezing weather, set in February, 1899.

Diaries, journals and other records kept by Washingtonians in the early and mid-19th century also attest to extreme weather conditions.

William P. Jackson's Chronicles of Georgetown (1751-1878) noted a low temperature of 16 degrees below zero in January, 1835, "the coldest ever experienced in this latitude." He said people were skating on the frozen Potomac River as late as March 3 that year. The modern record low is 15 degrees below zero, observed on Feb. 11, 1899.

A diary of Ann Thornton, wife of the original architect of the Capitol, William Thornton, notes a frost on May 21, 1800, more than a week later in the spring than the latest frost - May 12, 1913 - on record at the National Weather Service.

Climatologists at NOAA caution against reliance on specific data in the pre-1871 records, noting that the calibration of measuring instruments then was sometimes fractionally different from that of the standardized thermometers and other instruments today. However, as a reference to general weather conditions, they said, the older records are in most cases dependable.

For many years during the mid-19th century, records were kept at the National Observatory, then at 24th and E Streets NW.Hand written ledgers of hourly and daily temperature and barometric pressure readings show that observatory employees were not always punctilious about their jobs. Hourly observations were often skipped. Occasionally, an entire day would go by with no entries.

"Observer indisposed and chilly," an employee scrawled across the bottom of an otherwise empty page for Sept. 24, 1848.

On July 1, 1852, the observer entered temperature and other readings for 9 and 10 a.m., then abruptly stopped with the message: "Left the observatory to attend the funeral of Henry Clay." The famous statesman and orator had died two days earlier at the National Hotel in downtown Washington.

Record keeping and the art of forecasting weather have both improved since the mid-19th century, but the variety of predictions for the upcoming winter here suggests that forecasting is not yet a perfect science.

NOAA, even with its sophisticated network of observation posts and research facilities, is cautious in formulating long range 90-day forecasts, which it calls "outlooks."

Asked by a Senate Intergovernmental Affairs subcommittee last month to forecast the severity of the upcoming winter, Don Gillman, head of the NOAA's long range prediction group, testified that a "first, very preliminary look" at "scattered clues" points toward a "national temperature pattern in which the northeastern quarter of the country and the central Mississippi Valley seem the most likely to experience a colder winter than normal and the southwestern quarter of the country and the central Mississippi Valley seem the most likely to experience a colder winter than normal and the southwestern quarter most likely to enjoy a mild one."

He added that this "tentative picture . . . should not be given more than a 55 per cent chance of verifying at any individual city."

Private weather consultant Krick, who headed the Allied weather service in Europe during World War II and accurately predicted weather conditions for the Normandy invasion, is at wide variance with the government on the upcoming winter.

"I would expect a mild winter in the Washington area relative to normal winters and relative to last winter," he said in a telephone interview.

The Old Farmer's Almanac has a somewhat different scenario for the middle Atlantic coastal coastal area, which includes Washington.

"A cold November is expected to be followed by more than average rain and snow in the next two months, but without extreme cold," it says, although it predicts what it calls "rain and heavy snow, blizzard" for Jan. 24 through 28.

February, unlike Krick's forecast, should average four degrees below normal, says the Farmer's Almanac with snow likely from the 10th through the 19th and again on the 27th and 28th.

The Hagers-Town Almanack has still another arrangement with November, January and March below normal and December and February average in temperature.

"We look for 84 cold days, 67 wet days and 16 cyclonic storms" throughout the winter, says the almanack. "The winter will be longer than, not quite as cold as, and less concentrated than the previous winter. It will be wetter with fewer but heavier storms."

Jeane Dixon says the "first sign of real winter should be around noon on Nov. 22 or 23," with increasing cold and light snow, but we will have really adverse weather beginning about Jan. 22 going into February."

She concluded her forecast by predicting an unspecified "natural disaster" around the 13th to 15th of May, 1978.

"I don't know what it is or where it will be," she said, "but we can't do anything about it."