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
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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
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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