662
NGUS86 KRSA 201335
HCMRSA
HYDROMETEOROLOGICAL COORDINATION MESSAGE
NATIONAL WEATHER SERVICE / CALIFORNIA NEVADA RFC / SACRAMENTO CA
635 AM PDT WED MAY 20 2026
...WARMING TREND THE REST OF THE WEEK AS HIGH PRESSURE PUSHES
TOWARDS THE WEST COAST...
...AFTERNOON SHOWERS OVER THE CREST OF THE SIERRA THURS-SUN,
POSSIBLE LIGHT SHOWERS OVER THE N COAST & CA/OR BORDER INTO TUES
AM...
METEOROLOGICAL CONDITIONS (WED AM - TUE AM)
TROUGHING REMAINS OVER THE INTERIOR OF THE WESTERN US AS AN UPPER
RIDGE PUSHES CLOSER TO THE WEST COAST FROM OFFSHORE. THIS WILL KEEP
TEMPERATURES BELOW NORMAL OVER NV AND ABOVE NORMAL FOR MOST OF CA
TODAY. THE REST OF THE WEEK, THE RIDGE WILL SHOVE THAT TROUGHING
FURTHER INLAND WHILE CREEPING CLOSER TO THE COAST RESULTING IN A
WARMING TREND. MODELS DO HAVE A DISORGANIZED LOW FORMING WEST OF
BAJA TOWARDS THE END OF THE WEEK, BUT 500MB HEIGHTS ARE STILL
RELATIVELY HIGH AND WILL NOT ACT TO MITIGATE THIS WARMING OUTSIDE OF
FAR SOUTHERN CA. TEMPERATURE ANOMALIES ARE EXPECTED AT +5 TO +15 DEG
F AWAY FROM THE COAST. THESE WARMER TEMPERATURES LOOK TO STICK
AROUND THROUGH THE REST OF THE CURRENT FORECAST WINDOW. POTENTIAL
FOR SOME COOLING LOOKING OUT INTO THE EXTENDED AS SOME
MODELS/ENSEMBLES HAVE A STRONGER UPPER LOW DESCENDING IN FROM THE
PACNW EARLY TO MID NEXT WEEK. TIMING IS STILL A SOURCE OF
UNCERTAINTY, THE DET GFS/ECMWF BRING IN SOME LIGHT SHOWERS OVER THE
NORTH COAST TOWARDS THE END OF THE PERIOD. THE OFFICIAL FORECAST
ONLY HAS A FEW HUNDREDTHS OF AN INCH OR SO.
MODELS CONTINUE TO SHOW SOME CONVECTIVE SCATTERED SHOWERS (AND MAYBE
A THUNDERSTORM) DEVELOPING OVER THE CREST OF THE SIERRA IN THE
AFTERNOONS TOMORROW ONWARDS. LOW CONFIDENCE AGAIN WITH THE ECMWF
STILL HAVING THE MOST BUY IN. ANY AMOUNTS LOOK RELATIVELY LIGHT AT
THIS POINT.
FREEZING LEVELS TODAY BACK UP ABOVE 10.5 KFT AND UP TO 12.5 KFT
RISING THROUGHOUT THE REST OF THE WEEK UP TO 12-13.5 KFT BY WEEKS
END. POTENTIAL FOR LEVELS TO LOWER BY QUITE A BIT OVER NRN CA INTO
TUESDAY, BUT THIS WILL DEPEND ON THE TIMING OF THAT LOW MENTIONED
ABOVE. OFFICIAL FORECAST FOR NOW HAS FREEZING LEVELS 6.5-9 KFT NORTH
OF SHASTA BY 12Z TUES.
PLEASE NOTE: THIS PRODUCT MAY NOT BE ROUTINELY UPDATED.
PLEASE REFER TO THE FOLLOWING PRODUCT ISSUED BY THE CNRFC
WWW.CNRFC.NOAA.GOV/DAILY-BRIEFING FOR A GRAPHICAL SUMMARY OF
WEATHER AND HYDROLOGIC CONDITIONS.
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
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