759  
NGUS86 KRSA 291550  
HCMRSA  
 
HYDROMETEOROLOGICAL COORDINATION MESSAGE  
NATIONAL WEATHER SERVICE / CALIFORNIA NEVADA RFC / SACRAMENTO CA  
750 AM PST SUN JAN 29 2023  
   
..COOL SYSTEM CURRENTLY MOVING SOUTH ACROSS THE AREA INTO MON/TUE
 
   
..NEXT WEAK SYSTEM ARRIVES TOWARD THE END OF THE WEEK
 
 
   
METEOROLOGICAL CONDITIONS (SUN AM - SAT AM)
 
 
THE S/WV TROF AXIS HAS CROSSED THE CA/OR BORDER THIS MORNING AS THE  
DISTURBANCE CONTINUES TO DROP SOUTH ON THE DOWNSTREAM SIDE OF A  
NARROW WAVELENGTH GENERALLY ALIGNED ALONG 140W. RADAR IMAGERY SHOWS  
THE BEST CONCENTRATION OF SCATTERED ECHOES ALONG THE FRONTAL  
BOUNDARY FROM THE NORTHERN/CENTRAL SACRAMENTO VALLEY BACK ACROSS THE  
NORTHERN SIERRA AND ALONG I-80 IN NV. ANOTHER AREA OF WEAKER ECHOES  
ARE STREAMING ONSHORE FROM NORTHWEST TO SOUTHEAST ACROSS THE SF BAY  
AREA AND MONTEREY BAY.  
 
THROUGH TODAY...LOOK FOR THE S/WV TROF TO CONTINUE TO DROP SOUTH  
ACROSS CA BEFORE REACHING NEAR POINT CONCEPTION ON MONDAY MORNING.  
THE SYSTEM WILL ENTRAIN A BIT OF MOISTURE GIVEN ITS CLOSER  
TRAJECTORY TO THE PACIFIC...AS MODELS SHOW APPROX 0.50-INCH PW AIR  
AHEAD OF THE COLD FRONT. BEST PRECIP TODAY WILL FALL OVER MUCH OF  
THE SIERRA WITH 0.25- TO LOCALLY 0.50-INCH AND THEN AS THE SYSTEM  
MOVES CLOSER TO SOUTHERN CA ALONG COASTAL SECTIONS FROM LOS ANGELES  
TO SAN DIEGO WITH 0.25- TO 0.75-INCH OVER THE HIGHER TERRAIN.  
 
FOR MONDAY INTO TUESDAY...THE SYSTEM REALLY SLOWS DOWN ITS FORWARD  
PROGRESS AS THE S/WV TROF FORMS A CUTOFF LOW JUST OFF THE SOUTHERN  
CA COAST AN BEGINS TO SWING TOWARD THE EAST. THIS WILL CONTINUE  
PRECIP ACROSS SOUTHERN CA WITH SLIGHTLY HIGHER AMOUNTS NOW FORECAST  
FOR THE HIGHER TERRAIN BETWEEN SOUTHWEST SAN BERNARDINO COUNTY DOWN  
THROUGH SAN DIEGO COUNTY. LOOK FOR AMOUNTS IN THE RANGE OF 0.25- TO  
0.75-INCH WITH SOME LOCATIONS EAST OF SAN DIEGO CLOSER TO 1.00-INCH.  
 
BY LATER TUESDAY THE SYSTEM WILL FINALLY CROSS OVER NORTHERN BAJA  
WITH FLOW BECOMING OFFSHORE ACROSS SOUTHERN CA ON THE NORTH AND WEST  
SIDE OF THE UPR LOW...SHUTTING OFF MUCH OF THE PRECIP. MAYBE A FEW  
SCATTERED SHOWERS WILL EXIST RIGHT NEAR THE CA/MX BORDER.  
 
FOR THE MIDDLE OF THE WEEK...AN UPR RIDGE WILL SLIDE ACROSS THE WEST  
COAST FOR DRY CONDITIONS. THE TRAJECTORY OF THE NEXT SYSTEM WILL BE  
MORE TYPICAL FROM THE WEST...PRIMARILY AFFECTING THE REGION TOWARD  
THE END OF THE WEEK. THERE ARE DEFINITELY MODEL DIFFERENCES IN THE  
TIMING OF THIS SYSTEM...BUT OVERALL LOOK FOR THIS S/WV TROF TO  
WEAKEN AS IT APPROACHES THE WEST COAST AND THEN SHIFT MORE NORTHEAST  
TOWARD THE PACIFIC NORTHWEST. MAINLY LIGHT PRECIP IS EXPECTED FROM  
THIS SYSTEM WITH THE EC AND GFS ON THE DRIER SIDE AND THE CMC  
SHOWING A BIT MORE WITH A STRONGER S/WV TROF ACROSS NORTHERN CA. FOR  
NOW...FOLLOWED CLOSE TO THE 13Z NBM IN THE EXTENDED.  
 
QPF GRAPHICS ARE AVAILABLE AT WWW.CNRFC.NOAA.GOV/QPF.PHP  
 
*********************** CONTACT INFORMATION ************************  
 
CNRFC OFFICE HOURS PHONE: 1 (916) 979-3056 EXTENSION 338  
AFTER-HOURS CALLING SERVICE: 1 (800) 218-0858  
LEAVE NAME...OFFICE...AND PHONE NUMBER  
 
KOZLOWSKI  
 

 
 
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