2001 Pittsburgh, Grtr. Pitt. Airport Pennsylvania (PIT)

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2001 PITTSBURGH, GRTR. PITT. AIRPORT PENNSYLVANIA (PIT)

Pittsburgh lies at the foothills of the Allegheny Mountains at the confluence of the Allegheny and Monongahela Rivers which form the Ohio. The city is a little over 100 miles southeast of Lake Erie. It has a humid continental type of climate modified only slightly by its nearness to the Atlantic Seaboard and the Great Lakes.

The predominant winter air masses influencing the climate of Pittsburgh have a polar continental source in Canada and move in from the Hudson Bay region or the Canadian Rockies. During the summer, frequent invasions of air from the Gulf of Mexico bring warm humid weather. Occasionally, Gulf air reaches as far north as Pittsburgh during the winter and produces intermittent periods of thawing. The last spring temperature of 32 degrees usually occurs in late April and the first in late October. The average growing season is about 180 days. There is a wide variation in the time of the first and last frosts over a radius of 25 miles from the center of Pittsburgh due to terrain differences.

Precipitation is distributed well throughout the year. During the winter months about a fourth of the precipitation occurs as snow and there is about a 50 percent chance of measurable precipitation on any day. Thunderstorms occur normally during all months, except midwinter, and have a maximum frequency in midsummer. The first appreciable snowfall generally occurs in late November and usually the last occurs early in April. Snow lies on the ground in the suburbs on an average of about 33 days during the year.

Seven months of the year, April through October, have sunshine more than 50 percent of the possible time. During the remaining five months cloudiness is heavier because the track of migratory storms from west to east is closer to the area and because of the frequent periods of cloudy, showery weather associated with northwest winds from across the Great Lakes. Cold air drainage induced by the many hills leads to the frequent formation of early morning fog which may be quite persistent in the river valleys during the colder months.

The Allegheny River flowing south and the Monongahela River flowing north meet to form the Ohio River at Pittsburgh. Heavier rainfall and steeper topography cause the Monongahela River to flood more frequently than the Allegheny River.

Both rivers combine to cause the Ohio River at Pittsburgh to reach the 25 foot flood stage approximately once every four years. The serious flood level of 30 feet is reached much less frequently.

NORMALS, MEANS, AND EXTREMES

PITTSBURGH, PA (PIT)

LATITUDE:    LONGITUDE:    ELEVATION (FT):    TIME ZONE:    WBAN: 94823

40 30′ 05″ N  80 13′ 52″ W  GRND:  1172  BARO:  1175  EASTERN (UTC + 5)

ELEMENTPORJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECYEAR
TEMPERATURE FNORMAL DAILY MAXIMUM3033.736.949.060.370.678.982.680.874.362.550.438.659.9
MEAN DAILY MAXIMUM5435.538.748.260.870.979.382.881.274.463.150.539.260.4
HIGHEST DAILY MAXIMUM4969768289919810310097878274103
YEAR OF OCCURRENCE199920001998199019871988198819881954195919611982JUL 1988
MEAN OF EXTREME MAXS.5458.361.273.480.885.690.391.990.387.779.271.260.977.6
NORMAL DAILY MINIMUM3018.520.329.838.848.456.961.660.253.542.334.124.440.7
MEAN DAILY MINIMUM5420.322.329.639.649.157.862.260.953.742.934.225.041.5
LOWEST DAILY MINIMUM49-22-12-114263442393116-1-12-22
YEAR OF OCCURRENCE199419791980198219701972196319821959196519581989JAN 1994
MEAN OF EXTREME MINS.54-.61.711.223.034.343.750.248.638.028.117.36.125.1
NORMAL DRY BULB3026.128.739.449.659.567.972.170.563.952.442.331.550.3
MEAN DRY BULB5427.830.638.950.260.068.672.571.064.253.042.232.050.9
MEAN WET BULB1826.529.134.944.453.762.165.864.658.247.638.630.246.3
MEAN DEW POINT1821.022.727.636.647.757.361.560.454.042.232.924.840.7
NORMAL NO. DAYS WITH:
MAXIMUM 90300.00.00.00.00.31.63.41.70.60.00.00.07.6
MAXIMUM 323014.510.33.10.10.00.00.00.00.00.01.39.939.2
MINIMUM 323027.323.919.58.40.90.00.00.00.04.314.124.5122.9
MINIMUM 0302.61.50.10.00.00.00.00.00.00.0*0.85.0
H/CNORMAL HEATING DEG. DAYS30120610167944622143661410040068110395968
NORMAL COOLING DEG. DAYS3000004412322718467900654
RHNORMAL (PERCENT)3070676460636669717268707268
HOUR 01 LST3072716966727780828277747575
HOUR 07 LST3075747472767982868681787778
HOUR 13 LST3065625750525254565755626757
HOUR 19 LST3067635852555760636663677062
SPERCENT POSSIBLE SUNSHINE4932364346505557555551362945
W/OMEAN NO. DAYS WITH:
HEAVY FOG(VISBY 1/4 MI)501.41.21.00.81.31.11.62.12.31.81.41.817.8
THUNDERSTORMS500.20.51.73.45.16.96.65.43.01.20.60.334.9
CLOUDINESSMEAN:
SUNRISE-SUNSET (OKTAS)446.56.26.05.85.55.24.94.94.84.96.06.45.6
MIDNIGHT-MIDNIGHT (OKTAS)326.35.95.75.45.14.94.64.44.54.65.86.25.3
MEAN NO. DAYS WITH:
CLEAR442.93.34.54.45.34.85.46.67.37.83.72.758.7
PARTLY CLOUDY446.05.96.88.39.011.812.811.610.18.86.35.7103.1
CLOUDY4422.219.119.817.316.713.412.712.912.514.420.022.6203.6
PRMEAN STATION PRESSURE(IN)2828.7428.7528.7028.6828.6928.7128.7428.7528.8028.7928.7728.7628.74
MEAN SEA-LEVEL PRES. (IN)1830.0930.0930.0529.9729.9929.9930.0230.0630.0830.1230.1130.1230.06
WINDSMEAN SPEED (MPH)4410.510.310.810.58.88.07.47.07.68.39.610.09.1
PREVAIL. DIR (TENS OF DEGS)3326272727232324232326262626
MAXIMUM 2-MINUTE:
SPEED (MPH)541383851405345463839363753
DIR. (TENS OF DEGS)27203030313429332031322634
YEAR OF OCCURRENCE199920011999199820001998200120011999199920012000JUN 1998
MAXIMUM 5-SECOND:
SPEED (MPH)548554561596261604747475262
DIR. (TENS OF DEGS)27262831223433342131312334
YEAR OF OCCURRENCE199920011997199819971998199720011999199920012000JUN 1998
PRECIPITATIONNORMAL (IN)302.542.393.413.153.593.713.753.212.972.362.852.9236.85
MAXIMUM MONTHLY (IN)496.255.986.107.616.5610.298.717.866.008.2011.058.5111.05
YEAR OF OCCURRENCE197819561967196419891989199219871990195419851990NOV 1985
MINIMUM MONTHLY (IN)490.770.511.140.481.210.641.620.780.280.160.900.400.16
YEAR OF OCCURRENCE198119691969197119651992198919571985196319761955OCT 1963
MAXIMUM IN 24 HOURS (IN)491.692.302.002.152.903.114.413.062.593.561.972.764.41
YEAR OF OCCURRENCE198619751964196419971996199919561990195419851990JUL 1999
NORMAL NO. DAYS WITH:
PRECIPITATION 0.013016.414.015.413.612.911.810.49.510.010.513.316.7154.5
PRECIPITATION 1.00300.30.30.30.40.70.80.90.90.50.20.30.35.9
SNOWFALLNORMAL (IN)3012.69.97.71.70.20.00.00.00.00.23.28.143.6
MAXIMUM MONTHLY (IN)4840.224.234.18.13.1TTTT8.513.921.240.2
YEAR OF OCCURRENCE197819721993198719661990199119941989199319951974JAN 1978
MAXIMUM IN 24 HOURS (IN)4814.012.323.87.73.1TTTT6.610.512.523.8
YEAR OF OCCURRENCE196619601993198719661990199119941989199319581974MAR 1993
MAXIMUM SNOW DEPTH (IN)532616257100001221326
YEAR OF OCCURRENCE19781961199319871963199219501974JAN 1978
NORMAL NO. DAYS WITH:
SNOWFALL 1.0303.93.12.30.50.10.00.00.00.00.10.92.513.4
PRECIPITATION (inches) 2001 PITTSBURGH, GRTR. PITT. AIRPORT PA (PIT)
YEARJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECANNUAL
19721.843.643.684.371.385.082.981.795.422.154.703.0440.07
19732.031.803.864.695.873.122.163.403.564.452.652.1539.74
19743.472.103.723.265.355.083.302.934.421.123.064.0241.83
19753.344.644.622.271.844.584.387.565.063.461.772.9046.42
19763.251.744.451.241.993.374.721.253.303.760.901.8131.78
19772.060.874.123.262.572.853.382.663.132.442.593.2733.20
19786.250.541.652.254.264.112.153.652.643.421.625.2437.78
19794.803.121.323.174.491.734.316.843.602.462.432.2940.56
19801.561.325.652.944.324.346.765.101.292.422.381.3839.46
19810.774.202.124.922.048.203.820.984.131.821.503.0037.50
19824.441.933.521.443.983.052.361.972.800.403.332.7932.01
19831.191.583.504.335.244.823.323.132.423.673.944.2741.41
19841.402.052.323.725.221.983.015.150.843.453.143.0435.32
19851.431.453.371.645.802.264.062.640.282.2711.052.2638.51
19862.493.431.381.941.675.245.663.042.332.833.923.4737.40
19872.230.712.655.302.416.302.427.863.970.922.022.4139.20
19881.493.462.561.972.781.262.822.042.341.402.802.1727.09
19891.993.425.521.436.5610.291.621.124.572.041.562.3942.51
19903.303.311.473.486.194.246.593.596.003.512.058.5152.24
19912.551.882.922.563.293.823.741.633.450.551.973.6632.02
19922.131.733.542.302.310.648.714.772.911.473.312.8336.65
19932.992.924.143.662.853.352.852.443.872.774.302.1238.26
19943.902.135.003.722.542.913.277.753.590.883.642.0141.34
19952.231.731.561.703.723.743.061.751.803.242.741.6228.89
19963.682.544.544.422.957.954.011.995.632.962.831.9845.48
19971.581.153.221.576.333.951.823.802.900.955.981.2934.54
19983.632.571.915.002.396.712.023.321.092.271.501.8134.22
19994.882.431.244.194.121.676.252.211.971.553.462.2436.21
20001.702.532.263.155.695.646.283.663.072.091.382.6440.09
20011.351.093.283.752.113.433.157.122.232.333.472.4335.74
POR= 130 YRS2.862.453.263.123.413.793.913.232.622.382.442.6736.14
AVERAGE TEMPERATURE (F) 2001 PITTSBURGH, GRTR. PITT. AIRPORT PA (PIT)
YEARJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECANNUAL
197229.626.536.448.561.863.871.270.665.348.439.337.249.9
197329.728.848.349.356.470.973.273.266.556.144.133.352.5
197434.029.941.251.858.365.273.172.862.252.443.932.551.4
197532.632.136.344.363.067.872.873.058.853.346.332.951.1
197623.537.245.250.655.668.467.465.359.945.933.123.948.0
197711.426.943.750.863.063.871.868.164.750.545.631.149.3
197822.620.936.951.060.269.473.071.466.249.143.032.749.7
197921.418.043.149.759.167.770.369.663.450.944.734.649.4
198026.924.235.648.160.366.275.074.567.149.538.628.649.6
198120.531.435.651.958.468.872.169.761.949.440.329.449.1
198220.928.438.445.364.763.772.468.263.454.444.739.950.4
198330.032.640.747.155.867.873.072.864.453.043.525.450.5
198423.236.432.249.255.369.768.570.861.458.340.239.350.4
198522.127.742.155.060.664.270.569.665.355.247.127.450.6
198628.331.341.153.162.068.373.368.666.654.240.433.151.7
198728.032.641.950.063.070.975.771.865.147.846.235.152.3
198826.629.039.349.461.468.576.975.163.546.644.231.951.0
198935.527.841.147.058.069.074.171.664.853.340.619.250.2
199036.836.944.051.357.768.371.770.563.755.045.538.053.3
199129.735.443.054.568.772.675.474.464.655.741.635.354.2
199230.534.338.851.359.166.072.467.963.750.142.933.950.9
199335.127.837.650.061.968.975.775.463.351.743.031.751.8
199421.129.537.853.956.772.974.570.063.853.447.738.251.6
199531.026.542.848.660.472.075.877.864.356.338.127.751.8
199627.530.134.750.760.072.369.670.663.752.036.336.550.3
199728.135.140.546.454.368.171.768.262.152.639.033.550.0
199837.138.542.451.064.467.171.273.167.253.144.437.853.9
199930.134.035.151.861.069.476.069.064.252.346.734.652.0
200027.736.044.950.262.569.768.869.162.354.739.523.150.7
200128.435.135.354.360.068.470.273.162.154.248.237.552.2
POR= 126 YRS30.031.239.950.961.670.274.272.566.254.743.033.252.3

REFERENCE NOTES:

PAGE 1:

THE TEMPERATURE GRAPH SHOWS NORMAL MAXIMUM AND NORMAL MINIMUM DAILY TEMPERATURES (SOLID CURVES) AND THE ACTUAL DAILY HIGH AND LOW TEMPERATURES (VERTICAL BARS).

PAGE 2 AND 3:

H/C INDICATES HEATING AND COOLING DEGREE DAYS.

RH INDICATES RELATIVE HUMIDITY

W/O INDICATES WEATHER AND OBSTRUCTIONS

S INDICATES SUNSHINE.

PR INDICATES PRESSURE.

CLOUDINESS ON PAGE 3 IS THE SUM OF THE CEILOMETER AND SATELLITE DATA NOT TO EXCEED EIGHT EIGHTHS (OKTAS).

GENERAL:

T INDICATES TRACE PRECIPITATION, AN AMOUNT GREATER THAN ZERO BUT LESS THAN THE LOWEST REPORTABLE VALUE.

+ INDICATES THE VALUE ALSO OCCURS ON EARLIER DATES.

BLANK ENTRIES DENOTE MISSING OR UNREPORTED DATA.

NORMALS ARE 30–YEAR AVERAGES (1961–1990).

ASOS INDICATES AUTOMATED SURFACE OBSERVING SYSTEM.

PM INDICATES THE LAST DAY OF THE PREVIOUS MONTH.

POR (PERIOD OF RECORD) BEGINS WITH THE JANUARY DATA MONTH AND IS THE NUMBER OF YEARS USED TO COMPUTE THE MEAN. INDIVIDUAL MONTHS WITHIN THE POR MAY BE MISSING.

WHEN THE POR FOR A NORMAL IS LESS THAN 30 YEARS, THE NORMAL IS PROVISIONAL AND IS BASED ON THE NUMBER OF YEARS INDICATED.

0.* OR * INDICATES THE VALUE OR MEAN–DAYS–WITH IS BETWEEN 0.00 AND 0.05.

CLOUDINESS FOR ASOS STATIONS DIFFERS FROM THE NON–ASOS OBSERVATION TAKEN BY A HUMAN OBSERVER. ASOS STATION CLOUDINESS IS BASED ON TIME–AVERAGED CEILOMETER DATA FOR CLOUDS AT OR BELOW 12,000 FEET AND ON SATELLITE DATA FOR CLOUDS ABOVE 12,000 FEET.

THE NUMBER OF DAYS WITH CLEAR, PARTLY CLOUDY, AND CLOUDY CONDITIONS FOR ASOS STATIONS IS THE SUM OF THE CEILOMETER AND SATELLITE DATA FOR THE SUNRISE TO SUNSET PERIOD.

GENERAL CONTINUED:

CLEAR INDICATES 0–2 OKTAS, PARTLY CLOUDY INDICATES 3–6 OKTAS, AND CLOUDY INDICATES 7 OR 8 OKTAS. WHEN AT LEAST ONE OF THE ELEMENTS (CEILOMETER OR SATELLITE) IS MISSING, THE DAILY CLOUDINESS IS NOT COMPUTED.

WIND DIRECTION IS RECORDED IN TENS OF DEGREES (2 DIGITS) CLOCKWISE FROM TRUE NORTH. "00" INDICATES CALM. "36" INDICATES TRUE NORTH.

RESULTANT WIND IS THE VECTOR AVERAGE OF THE SPEED AND DIRECTION.

AVERAGE TEMPERATURE IS THE SUM OF THE MEAN DAILY MAXIMUM AND MINIMUM TEMPERATURE DIVIDED BY 2.

SNOWFALL DATA COMPRISE ALL FORMS OF FROZEN PRECIPITATION, INCLUDING HAIL.

A HEATING (COOLING) DEGREE DAY IS THE DIFFERENCE BETWEEN THE AVERAGE DAILY TEMPERATURE AND 65 F.

DRY BULB IS THE TEMPERATURE OF THE AMBIENT AIR.

DEW POINT IS THE TEMPERATURE TO WHICH THE AIR MUST BE COOLED TO ACHIEVE 100 PERCENT RELATIVE HUMIDITY.

WET BULB IS THE TEMPERATURE THE AIR WOULD HAVE IF THE MOISTURE CONTENT WAS INCREASED TO 100 PERCENT RELATIVE HUMIDITY.

ON JULY 1, 1996, THE NATIONAL WEATHER SERVICE BEGAN USING THE "METAR" OBSERVATION CODE THAT WAS ALREADY EMPLOYED BY MOST OTHER NATIONS OF THE WORLD. THE MOST NOTICEABLE DIFFERENCE IN THIS ANNUAL PUBLICATION WILL BE THE CHANGE IN UNITS FROM TENTHS TO EIGHTS (OKTAS) FOR REPORTING THE AMOUNT OF SKY COVER.

HEATING DEGREE DAYS (base 65 F) 2001 PITTSBURGH, GRTR. PITT. AIRPORT PA (PIT)
YEARJULAUGSEPOCTNOVDECJANFEBMARAPRMAYJUNTOTAL
1972-732011635087678531087100650847426425563
1973-742855274621978957978729403223545282
1974-75001243846301001997916881617116485714
1975-76001923625549891278801605453301245559
1976-7715591595879531268165510606584361381027090
1977-78114178442583104313071229860412209386253
1978-79438048565699313461311671458219386264
1979-80232611143860193511751177906500172716135
1980-81054847678711171372936904391223186277
1981-8231015947573610981361101781958682676413
1982-839231193366057701080904746535280445451
1983-84102126365639122312938231008471305166281
1984-8512716521473479013221038701334163655545
1985-863911630053111601131936737368148375476
1986-87140653467339831139904710451145225539
1987-884206152956092011811040792461149645781
1988-89538357061910189051033739532260255792
1989-901141023647231414869781657439229495642
1990-914111631457782910858206743376354825
1991-92001273086989131063880805417210505471
1992-931171164576579569201037841445135435625
1993-940011840765410281357988836345278216032
1994-95010803515168241047107167848716355232
1995-96007926979911501155100593043621556043
1996-971411043978538731136832755554329355883
1997-9822110940177297385873671641578755156
1998-9900523696168371076861917387140405295
1999-00161013865419351148833620442135335181
2000-0181415831776112911123833912350171435981
2001-172125341497846
COOLING DEGREE DAYS (base 65 F) 2001 PITTSBURGH, GRTR. PITT. AIRPORT PA (PIT)
YEARJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECANNUAL
19720000346821919276000589
1973000105185264269108500846
197400013196625824745540657
197500006013724825712700721
19760012514134997312000358
197700314837523114172040623
1978000069178260207122000836
197900094112519317570700620
1980000034115317306118000890
198100052513923016072000631
198200007933246127771530580
198300033135263251115000770
1984000312165127194631300577
1985000413349181160130400598
198600320651442651571212000795
198700069320434224072010958
198800004417438132247700975
1989005049154291225100900833
19900014379153218179831300706
19910002718423933329812427001232
19920009338723311286300563
199300024516633732773110952
1994000212826430217551020843
1995000027220342402657001063
1996000116723016218671000727
199700024134217128292400538
19980022067147199254125600820
199900002417835013683000771
200000526718113114783600622
20010003420152184258441200704
SNOWFALL (inches) 2001 PITTSBURGH, GRTR. PITT. AIRPORT PA (PIT)
YEARJULAUGSEPOCTNOVDECJANFEBMARAPRMAYJUNTOTAL
1972-730.00.00.01.86.12.93.46.14.61.4T0.026.3
1973-740.00.00.00.00.84.84.92.22.31.6T0.016.6
1974-750.00.00.0T2.621.210.113.99.81.10.00.058.7
1975-760.00.00.00.01.93.821.83.34.30.50.00.035.6
1976-770.00.00.0T6.67.926.56.40.91.3T0.049.6
1977-780.00.00.0T3.39.140.25.44.00.20.00.062.2
1978-790.00.00.00.02.33.218.213.72.01.40.00.040.8
1979-800.00.00.0T1.11.17.86.27.9T0.00.024.1
1980-810.00.00.0T9.76.312.511.97.6T0.00.048.0
1981-820.00.00.0T0.611.513.43.612.23.80.00.045.1
1982-830.00.00.0T0.18.83.912.04.31.00.00.030.1
1983-840.00.00.00.06.110.510.811.410.4T0.00.049.2
1984-850.00.00.00.01.54.814.68.10.27.20.00.036.4
1985-860.00.00.00.0T15.311.112.44.82.70.00.046.3
1986-870.00.00.00.01.00.911.61.17.38.10.00.030.0
1987-880.00.00.0T4.17.95.56.99.80.90.00.035.1
1988-890.00.00.00.21.14.04.24.17.50.6T0.021.7
1989-900.00.0T0.21.612.57.72.50.63.30.0T28.4
1990-910.00.00.00.0T4.64.83.64.2T0.00.017.2
1991-92T0.00.00.02.13.112.92.410.62.8T0.033.9
1992-930.00.00.01.31.514.12.118.534.10.50.00.072.1
1993-940.00.00.08.52.610.430.111.013.60.60.00.076.8
1994-950.0T0.00.00.2T7.69.06.40.20.00.023.4
1995-960.00.00.00.013.912.623.49.613.41.60.00.074.5
1996-970.00.00.00.04.46.10.00.0
1997-980.00.00.00.012.61.72.54.90.00.00.0
1998-990.00.00.0TT1.817.14.715.6T0.00.039.2
1999-000.00.00.0T2.13.212.08.41.10.3T0.027.1
2000-010.00.00.0T2.18.313.72.78.01.10.00.035.9
2001-T0.00.00.2T5.0
POR= 48 YRSTTT0.43.38.011.58.88.51.60.2T42.3

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