757  
NGUS86 KRSA 161434  
HCMRSA  
 
HYDROMETEOROLOGICAL COORDINATION MESSAGE  
NATIONAL WEATHER SERVICE / CALIFORNIA NEVADA RFC / SACRAMENTO CA  
735 AM PDT SAT OCT 16 2021  
   
..TURNING COOLER WITH PRECIP CHANCES INCREASING NORTHERN AREAS
 
 
   
METEOROLOGICAL CONDITIONS (SAT AM - FRI AM)
 
 
LATEST SETUP SHOWS AN UPR RIDGE OVER THE INTERIOR...ALIGNED FROM THE  
4-CORNERS REGION UP ACROSS THE GREAT BASIN WELL NORTH INTO ALBERTA.  
UPSTREAM OVER THE NORTHEAST PACIFIC...AN UPR TROF IS ALIGNED ALONG  
140W WITH A MODEST MOISTURE PLUME ENTRAINED JUST AHEAD OF THE COLD  
FRONT WITH THE LATEST BLENDED TPW IMAGERY SHOWING PW VALUES  
GENERALLY FROM 1.25- TO 1.50-INCHES.  
 
TODAY WILL BE A DRY DAY...AHEAD OF THE APPROACHING COLD FRONT.  
HOWEVER...THROUGH THE MORNING HOURS TOMORROW LOOK FOR THE UPR TROF  
TO SHARPEN AS IT REACHES THE COAST AND BEGINS TO SPREAD PRECIP ALONG  
THE NORTH COAST. WITH THIS SYSTEM...16/00Z MODELS ARE IN REASONABLE  
AGREEMENT WITH THE PROGRESSION OF THE PRECIP ACROSS THE REGION ON  
SUNDAY...PRIMARILY IMPACTING AREAS NEAR AND NORTH OF I-80 AND THE  
BEST AMOUNTS OVER THE HIGHER TERRAIN ALONG THE COAST FROM THE EEL  
RIVER BASIN NORTHWARD...AND THEN INLAND ALONG THE WEST SLOPE AND  
CREST OF THE CASCADES AND SIERRA DOWN TO ABOUT THE  
STANISLAUS/TUOLUMNE RIVER BASINS. AS THE S/WV TROF MOVES  
INLAND...LOOK FOR THE SYSTEM TO FORM AN UPR LOW ACROSS NORTHERN NV  
ON MONDAY AND SLOW ITS PROGRESSION TO THE EAST A BIT. BEST PRECIP  
WILL BE MAINLY OVER NORTHERN NV FROM ABOUT I-80  
NORTHWARD...IMPACTING THE HUMBOLDT RIVER BASIN.  
 
A TRANSITORY S/WV RIDGE WILL SLIDE ACROSS THE AREA LATE MONDAY INTO  
TUESDAY...BRINGING DRY CONDITIONS TO MUCH OF THE AREA WITH THE NEXT  
SYSTEM ROTATING FROM OFFSHORE TOWARD THE NORTHEAST WITH THE BEST  
FORCING CLIPPING THE REGION AS IT MAKES ITS WAY OVER THE PACIFIC  
NORTHWEST. THIS WILL CONFINE THE BEST PRECIP TO COASTAL AREAS FROM  
ABOUT THE RUSSIAN RIVER BASIN NORTHWARD. AS THE COLD FRONT DROPS  
SOUTH TOWARD THE I-80 CORRIDOR IT WILL WEAKEN WITH THE BETTER  
FORCING TO THE NORTH...AND SLOW AS THE STEERING FLOW BECOMES MORE  
PARALLEL TO THE BOUNDARY. THERE WILL BE PLENTY OF PW STILL AVAILABLE  
WITH A MOISTURE PLUME ADVECTING TOWARD THE WEST COAST FROM THE  
SOUTHWEST TOWARD THE I-80 CORRIDOR. WITH LITTLE FORCING...EXPECT  
PRECIP TO BE GENERALLY LIGHT ON WEDNESDAY.  
 
MODELS START TO SHOW SOME DISCREPANCIES FOR THE LATTER HALF OF THE  
WEEK AS THE EC SHOWS A MORE SHALLOW UPR TROF OFFSHORE...MAKING ITS  
WAY TOWARD THE COAST QUICKER THAN WHAT THE GFS IS INDICATING. THE  
GFS DIGS THE SYSTEM SOUTHWARD A BIT MORE...WHICH RESULTS IN AN  
OVERALL SLOWER ARRIVAL OF PRECIP. FOR NOW...USED WPC AS THE MAIN  
INFLUENCE WITH SOME SLIGHT INCLUSION OF THE EC AND GFS.  
 
OVERALL...THE UPCOMING WEEK WILL BE COOLER WITH OPPORTUNITIES FOR  
PRECIP ACROSS NORTHERN AREAS. DEFINITELY WELCOME CONSIDERING HOW  
MEAGER PRECIP HAS BEEN DURING RECENT OCTOBERS.  
 
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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