JULY 1999 MONTHLY REVIEW
Warm to start the month, cold with drizzle at the end. 4th of July was unusually pleasant, and warm, clear and WINDLESS conditions prevailed. Our coastal weather was primarily dominated by subtle changes in wind flow patterns along the coast. With the hot spell of early in the month, winds either blew from the NNE, or were light/absent -indicating a slackening and even slightly offshore pressure gradient between the coast and inland (Sacramento Valley, etc.) During the second week, wind direction gradually shifted to more typical WSW. But instead of remaining there, troughiness to our north caused winds to shift to SSW. A prime effect of these SSW winds is to move relatively warmer southern latitude water northward, and SST is now up to 56-58F in the imediate area. The warmer water is quite shallow, but it is sufficiently warm to cap ocean waters and prevent turnover/upwelling. Because the warmer water is jucier air, fog is enhanced, to the point of widespread drizzle along the coast and unseasonably cool temps at times in the valleys. A great example was during the first week, temps in the northern Sac. Valley (Red Bluff) set temp records of 118F. Temps closer to home (Gilroy) got to 113. However, by the second week, hi temps in Stockton were in the low to mid 70's...a good 20-25 degrees below normal for this time of year. Despite the locally warming Pacific coast waters, long range ENSO models now show a continuation of La Nina conditions is expected through the Winter of '99-'00. With global atmospheric heat further dissipating after the El Nino of '97-'98, this years La Nina influenced winter may be drier than last...possibly very much drier.
The monthly raw data is incomplete due to our rabbit eating the Wx station's power cord while we were on vacation.
MONTHLY CLIMATOLOGICAL SUMMARY for JUL. 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 60.0 72.5 9:00a 53.4 12:00m 2.0 0.0 0.00 3.8 22.0 3:30p S
2 57.0 66.2 9:00a 51.7 5:00a 6.1 0.0 0.00 6.9 21.0 4:00p S
3 57.1 63.2 3:00p 52.1 3:00a 7.3 0.0 0.00 6.4 24.0 12:30p SSW
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31 58.7 60.7 12:30p 55.8 11:30p 6.8 0.0 0.00 5.5 18.0 3:30p S
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58.2 72.5 1 51.7 2 22.2 0.0 0.00 0.7 24.0 3 SSW
Max >= 90.0: 0
Max <= 32.0: 0
Min <= 32.0: 0
Min <= 0.0: 0
Max Rain: 0.00 ON 7/01/99
Days of Rain: 0 (>.01 in) 0 (>.1 in) 0 (>1 in)
Heat Base: 65.0 Cool Base: 65.0 Method: (High + Low) / 2