Monthly Climatological Summary
Turlock, Stanislaus Co., CA (Lat 37^31'37"N, Lon 120^50'22"W, elev 123)
April 2000
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    Temperature Degree Days Pcpn  Bar Pressure  Humidity PkWind
     Max   Min   Heat  Cool       Max      Min  Max  Min  (MPH)
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01    84    43     1     0   .00  30.08  29.95   82   22    12
02    88    45     0     2   .00  30.04  29.94   96   24    10
03    91    52     0     7   .00  30.10  30.01  100   25    10
04    81    51     0     1   .00  30.16  30.03  100   36    14
05    80    46     2     0   .00  30.06  29.93   97   34    15
06    81    44     2     0   .00  30.13  30.03   93   27    14
07    82    44     2     0   .00  30.17  30.03   93   24    14
08    76    46     4     0   .00  30.11  30.02  100   30    20
09    75    45     5     0   .00  30.10  30.01   93   38    18
10    80    45     2     0   .00  30.05  29.97  100   36    17
11    85    53     0     4   .00  30.07  29.94   93   37    12
12    88    60     0     9     T  30.06  29.95   60   30    16
13    77    59     0     3   .06  30.09  29.93   87   34    18
14    74    54     1     0   .00  29.97  29.86   93   34    15
15    69    51     5     0   .00  29.96  29.86   89   44    14
16    65    54     5     0   .18  29.91  29.77   93   56    27
17    57    47    13     0  1.32  29.90  29.75  100   80    21
18    68    40    11     0   .00  30.13  29.90  100   39     9
19    72    43     7     0   .00  30.18  30.09   97   38    10
20    76    49     2     0   .00  30.13  29.97   89   40    14
21    79    51     0     0   .00  29.98  29.85   89   40    20
22    70    48     6     0   .00  30.13  29.98   93   47    14
23    71    42     8     0   .00  30.20  30.11  100   38    20
24    78    45     3     0   .00  30.16  30.03  100   32    16
25    80    50     0     0   .00  30.16  30.06   87   41    17
26    85    51     0     3   .00  30.10  29.94   96   37    14
27    80    53     0     2   .00  30.09  29.91   74   31    31
28    68    48     7     0   .00  30.16  30.07   69   28    23
29    78    43     4     0   .00  30.18  30.09   89   26    17
30    86    48     0     2   .00  30.15  30.03   93   28    12
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Means and Totals for April 2000
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Average Maximum Temperature:      77.4
Average Minimum Temperature:      48.3

Mean Temperature:                 62.9  (+ 1.2)

Maximum Temperature:                91  (4-03-00)
Minimum Temperature:                40  (4-18-00)

Degree Days Heating:                90
Degree Days Cooling:                33

Days with temperature 90F+:          1
Days with temperature <32F:          0

Precipitation:                    1.56  (+  .70)   Season: 12.31
Greatest one-day rainfall:        1.32  (4-17-00)

Snowfall:                          0.0  (Avg)      Season:   0.0

Maximum Pressure:                30.20  (4-23-00)
Minimum Pressure:                29.75  (4-17-00)

Minimum RH:                         22% (4-01-00)

Days with measurable pcpn:           3
Days with pcpn 1.00"+:               1
Thunderstorm days:                   0
Fog days:                            0

Peak Wind Gust (MPH):               31  (4-27-00)


NOTICE: All temperatures are in degrees Fahrenheit, precipitation
values in inches, pressure in inches Hg, and wind speeds
in MPH.


Summary....April 2000 in the northern San Joaquin Valley was reminiscent of Aprils in the late 1980s and early 1990s - warmest at the beginning of the month, wettest at mid-month, and coolest towards the end of the month. The temperature topped 90F for the first time this year on the 3rd, the earliest in the year the temp had reached 90F here since 1988. All of the month's rain came during a five day span in the middle of the month. The .06 inch of rain that fell here on the 13th broke a 34-day streak without measureable precipitation. Thunderstorms developed 25-35 miles north of here that afternoon, and as the storms grazed the far northeastern tip of the county, a severe thunderstorm warning was issued for that area. A break between storms came on the 14th-15th, although the weather wasn't totally calm across the area those two days. The Apr 15 issue of the Modesto Bee reported that a "twister" tore the roof off a carport at a mobile home park in east Modesto on the 14th (ed. note: It was probably a dust devil). What has proven to be this station's heaviest rainfall event of the 1999-2000 rainy season began late on the 16th and continued for much of the 17th. The 1.32 inch rainfall total on the 17th was the first one-day rainfall total over 1 inch recorded at this station since records began in 1987. The previous one-day rainfall record for April was .78 inch on Apr 23, 1988. Cool onshore breezes generally kept temperatures under 80F for the rest of the month. These pushes of marine air were for the most part nondescript, although the one on the 27th gave us wind gusts to 31 mph and brought the coastal stratus all the way into the valley.

I will be on vacation from May 5-15. Matt Wear will take over the daily temperature and precipitation readings for those days, so those data will be complete for the May summary.

Following are monthly data from ASOS/AWOS stations in the San Joaquin Valley.....

STATION          AVERAGE TEMP   |EXTREME TEMP |   PRECIPITATION
             Max  Min  Mean  Dep|Max Dy Min Dy|Total  Dep   Max Dy 
===================================================================
Stockton     75.5|46.2|60.8|+1.5| 88| 3| 38| 7| 1.20|+ .12|1.03|17|(a)
Modesto      75.2|49.1|62.1|+1.9| 88| 3| 43|18| 2.00|+1.03|1.69|17|(a)
Merced       74.8|45.8|60.3|+0.7| 87| 3| 38| 7| 2.06|+1.00|1.97|17|(a)
Madera       77.3|47.1|62.2|+2.3| 89| 3| 40| 1| 1.02|- .15| .93|17|
Fresno       77.4|50.9|64.1|+2.9| 91| 3| 44|18| 1.16|+ .19| .97|17|(a) 
Hanford      77.7|50.6|64.2|+4.2| 90|12| 45|29|  .97|+ .23| .88|17|
Visalia      76.4|48.9|62.7|+1.6| 90|12| 43|29| 1.04|+ .05|1.01|17|(b)
Porterville  76.6|46.3|61.5|-0.3| 88|27| 39|29|  .89|- .20| .65|17|(b)
Bakersfield  76.7|49.0|62.9|-0.1| 90|12| 39|19|  .57|  .00| .52|17|


(a) Maximum one-day rainfall total was for period beginning midnight
    PDT on the 17th.
    
(b) Maximum and minimum temperatures are rounded to the nearest
    whole degree Celsius, then converted to Fahrenheit.