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APRIL 1999 WEATHER SUMMARY

April was notable as the transition month for the '98-'99 rain season.  Early in the month, cold core upper lows continued an almost two month trend of moving N to S down the coast, and brought three moderate rain events . The rains were then followed by a nice period of sunny and warm temps in the middle of the month (80F on the 15th) then cool, blustery conditions to end with as another cold trough parked itself off the coast. Rain for the month totaled 2.29",  all occurring before the 11th, which is about 1" above normal. "Normal"  rain in April is a bit of a misnomer, as it typically either rains good, or hardly at all. Over the last 15 years, all but one year had either 0.00" to 1.00" or 2.00" - 2.89" of rain...or an "average " of 1.3" of rain... despite in no April did we have a "normal" month! Total rain for the year now stands at 26.82", about 3" above normal for the entire rainy season, and is unlikely to change much more before the official end of the season on June 30th. Reflecting the overall cold temps, during the low passage of 4/08, snow fell briefly in a squall in the middle of the day on Mt. Montara  (elev 2K') and some major pea-hail events whitened the lowlands (and my house) area for hours. The  main rainy season then appears to have culminated with a 1.26" event on the 11th, which was one of the highest individual rain events for the year..continuing the almost season long pattern of frequent, cold rains, but no major rain events. As the jet moved back north, lows after that went inland to our north then swung SE . In the middle of the month, just after Spring Training was finished, Arizona (Scottsdale) actually had 2 significant snow events from the very cold air plunging into the Southwest. One major Golf tournament was cancelled as a result. While the low cores  later in the month did not bring precip to our area, howling winds did occur.   Numerous days with gusts above 30 MPH were noted. For the month, a healthy 47 MPH was clocked on the 3rd.  A couple of bouts of offshore winds from highs building in back of the troughs between the 14th and 16th shot temps up to 80F at my house on the 15th. After that, cooler, windy onshore conditions set in, bringing a much more typical spring pattern, with lots of fog and overcast mornings. Surf has been above average and SST's are still around 50F, as 50F dew point and 100% humidity (fog to the ground) occurred on the 31st under calm conditions. Due to our proximity to the ocean, these type of conditions generally reflect SST to with a fraction of a degree (in the absence of super-saturation, that is).

 

MONTHLY CLIMATOLOGICAL SUMMARY for APR. 1999


NAME: HOME CITY: Pacifica  STATE: Ca  ELEV: 540'  LAT: 37.36'N  LONG: 122.27'W 


                   TEMPERATURE (°F), RAIN  (in), WIND SPEED (mph)


                                      HEAT  COOL        AVG
    MEAN                              DEG   DEG         WIND                 DOM
DAY TEMP  HIGH   TIME   LOW    TIME   DAYS  DAYS  RAIN  SPEED HIGH   TIME    DIR
------------------------------------------------------------------------------------
 1  48.5  56.2  11:30a  39.9   6:00a  16.9   0.0  0.00   2.7  18.0  12:30a     N
 2  52.2  62.0  11:30a  43.9   6:00a  12.0   0.0  0.00   3.0  16.0   9:00a     S
 3  48.2  52.9  12:00p  44.9  12:00m  16.1   0.0  0.00   7.6  47.0   4:00p   NNW
 4  48.8  56.0   1:00p  42.6   5:00a  15.7   0.0  0.00   4.7  24.0   5:30a     N
 5  47.1  51.5   4:30p  43.8  11:30p  17.3   0.0  0.61   6.9  32.0   8:30a     S
 6  47.6  56.1   3:30p  42.2   3:30a  15.8   0.0  0.03   3.0  20.0   1:30p   NNE
 7  49.3  51.4   2:00p  46.1  12:30a  16.3   0.0  0.01   5.8  21.0  12:00m     S
 8  45.6  50.6  11:30a  41.0   6:00p  19.2   0.0  0.38   6.8  35.0   3:30a     S
 9  46.9  53.3  12:00p  40.8   5:00a  18.0   0.0  0.00   3.8  22.0  12:30a     N
10  47.7  53.4  10:00a  43.3  12:30a  16.7   0.0  0.13   3.7  27.0  12:00m     S
11  49.1  53.6   6:00p  45.1   5:00a  15.7   0.0  1.13   2.9  23.0   1:30p     N
12  52.2  59.0  11:00a  46.6   3:00a  12.2   0.0  0.00   3.0  16.0   4:30p   SSW
13  53.0  61.8   1:00p  46.6   6:30a  10.8   0.0  0.00   1.6  10.0  10:00a    NE
14  61.0  76.7   2:30p  47.6   1:30a   2.9   0.0  0.00   2.2  20.0  12:30p    NE
15  67.2  79.3   3:30p  56.7   1:00a   0.0   3.0  0.00   3.3  20.0   8:30a    SW
16  65.6  77.8  12:30p  56.5  12:00m   0.0   2.2  0.00   1.7  13.0  10:00a   NNW
17  57.5  67.4   2:30p  49.7  12:00m   6.4   0.0  0.00   1.8  10.0  12:30p   SSW
18  54.9  63.6   1:30p  48.6   6:00a   8.9   0.0  0.00   2.8  10.0  12:00p   SSW
19  54.1  61.1   2:00p  50.5   4:30a   9.2   0.0  0.00   3.4  21.0   4:00p   SSW
20  51.6  56.9   3:30p  48.0  11:00p  12.5   0.0  0.00   4.4  19.0   8:30p   SSW
21  51.7  57.5  12:00p  47.3   5:00a  12.6   0.0  0.00   5.2  23.0  11:00a     W
22  53.5  60.3  12:00p  47.8   7:30a  11.0   0.0  0.00   5.7  36.0  12:30p     N
23  62.9  72.5  12:00p  53.6   7:00a   2.0   0.0  0.00   4.0  36.0  12:30a     N
24  56.6  70.3   9:00a  51.2   6:00a   4.3   0.0  0.00   5.1  30.0   2:30p   SSE
25  53.4  60.1   2:00p  50.2  11:30p   9.8   0.0  0.00   4.4  23.0  12:30a   SSW
26  51.7  58.2   1:00p  46.7  12:00m  12.5   0.0  0.00   4.5  23.0   5:30p   SSW
27  50.8  59.0   9:00a  46.3   5:30a  12.3   0.0  0.00   5.7  23.0   7:00a   WNW
28  50.6  60.3   9:00a  44.3   6:00a  12.7   0.0  0.00   4.7  29.0   6:30a     W
29  52.7  63.4   9:00a  43.3   6:00a  11.7   0.0  0.00   3.0  18.0   2:30p     W
30  55.9  68.1  12:00p  45.5   4:30a   8.2   0.0  0.00   2.4  15.0   6:30p     E
-------------------------------------------------------------------------------------
    52.9  79.3    15    39.9     1   339.7   5.2  2.29   4.0  47.0     3     SSW


Max >= 90.0:  0
Max <= 32.0:  0
Min <= 32.0:  0
Min <=  0.0:  0
Max Rain: 1.13 ON  4/11/99
Days of Rain: 5 (>.01 in) 4 (>.1 in) 1 (>1 in)
Heat Base:  65.0  Cool Base:  65.0  Method: (High + Low) / 2