National Weather Service United States Department of Commerce

Rivers are fed by melting snow over the higher elevations of the Sierra this time of year. The warmer the air gets, the faster the snow melts and the more dangerous rivers become. Rivers will be running fast and deep during the next several weeks and they will be unsafe places for swimmers, rafters and boaters. Water temperatures in these rivers are only in the 40s to lower 50s. Exposure to water this cold can quickly lead to hypothermia. Don’t risk your life or safety by venturing into any of these rivers!
A few strong thunderstorms could pop up over the higher elevations of the Sierra this afternoon. In addition to cloud to ground lightning, thunderstorms can bring strong, gusty winds and locally heavy downpours. Hikers and campers and others planning outdoor activities in the affected areas should keep a watchful eye on the sky this afternoon and be prepared to move to a place of safety when thunder is heard.
A recurrence of widespread triple digit heat is likely in the San Joaquin Valley this afternoon. Prolonged exposure to triple digit heat can pose a health risk to the elderly, persons with respiratory ailments and anyone who is not yet acclimated to hot weather. If you’re going to be outdoors during the hottest time of the day (between 1 pm and 6 pm), avoid strenuous exercise, stay hydrated and wear light colored, loose fitting clothing. Remember that going from hot air temperatures into cold water in area rivers could cause shock to the body and lead to drowning. Use caution if entering local waterways and remember to wear a life vest.

 

Text Product Selector (Selected product opens in current window)
Publications and Weather Highlights
 
Publications by NWS San Joaquin Valley Personnel

Technical Attachments are documents written by NWS Personnel describing different aspects of weather or to improve forecasting techniques. A complete list of these publications can be found on the Western Region Homepage. Below is a list of TM'sTA'sand TA Lites written by our office personnel. 
 
TA # Title Author
98-07 The Lemoore Naval Air Station Classic Supercell Tornado of 22 November 1996 Ray Kruzdlo
98-12 VR/SHEAR Interpretation Ray Kruzdlo
98-35 San Joaquin Valley Hail Event - December 13, 1995 Bob Nester
L03-15 Evaluation of KHNX WSR-88D Storm-Relative Velocity Products During A Tornadic Thunderstorm Jeffrey Nesmith
L03-40 Use of Local Analysis and Prediction System (LAPS) During a High Bouyancy / Low Shear Severe Thunderstorm Outbreak in the Central California Interior David Spector
03-09 The Application of Upper Level Heights in Diagnosing and Forecasting San Joaquin Valley Dense Fog Episodes Mark Burger
L03-48 An Analysis of the December 16, 2002 Grapevine Wind Event Mark Burger
04-06 The Prediction of Minimum Overnight Visibilities at the Fresno-Yosemite International Airport Utilizing Multiple Linear Regression Mark Burger
L04-18 A Southern Sierra Nevada Flash Flood Event Resulting from Monsoonal Convection Mark Burger
L05-04 The Unusual Frost Event of November 29 to December 4, 2004 Dan Gudgel
05-04 Pre-Frontal San Joaquin Valley Wind Events and the Use of Surface and Upper Air Data to Facilitate Their Prediction Mark Burger
L06-10 An Anaysis of a Heavy Precipitation Event Over Interior South-Central California Jeffrey Meyers and Larry Greiss
  An Analysis of the 7 July 2004 Rockwell Pass, CA Tornado: Highest Elevation Tornado Documented in the U.S. John P. Monteverdi, Roger Edwards,
Gregory A. Stumpf and Dan Gudgel
L07-08 El Nino and La Nina Episodes and Their Impact on the Weather in Interior Central California Christopher Stachelski
TM280 The Climate of Fresno, California Christopher Stachelski and Gary Sanger
TM281 The Climate of Bakersfield, California Christopher Stachelski and Gary Sanger
L14-04 Tornado Statistics for the WFO San Joaquin Valley-Hanford County Warning Area Gary Sanger and Jimmy Andersen