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AGUS76 KRSA 101541
HMDRSA
HYDROMETEOROLOGICAL DISCUSSION
NATIONAL WEATHER SERVICE / CALIFORNIA-NEVADA RFC / SACRAMENTO CA
830 AM PDT SAT OCT 10 2026
..UNSETTLED WEATHER BEGINNING TODAY WITH TS RACHEL MOVING ONSHORE
..BEST PRECIP FROM PORTIONS OF SOUTHERN CA INTO EASTERN NV ON SUN
METEOROLOGICAL CONDITIONS (SAT AM - FRI AM)
COOLER TEMPERATURES ACROSS THE REGION TODAY AS THE PATTERN HAS
SHIFTED TO TROFFING OVER THE EASTERN PAC/WESTERN US. AN UPPER LEVEL
CUTOFF HAS BEGUN PHASING WITH TROPICAL STORM RACHEL OFF THE SOCAL
AND BAJA COAST AND WILL EVENTUALLY LEAD TO UNSETTLED WEATHER TODAY
AND THROUGH THE WEEKEND ACROSS SOUTHERN CA AND INTO NEVADA.
THE TRACK OF RACHEL AND SUBSEQUENT SOUTHERLY FLOW ON THE EAST SIDE
OF THE LOW HAVE CONTINUED TO SHIFT AROUND OVER THE PREVIOUS 24HRS,
LEADING TO A MORE EAST/SOUTHWEST TRACK SINCE YESTERDAY MORNING'S
FORECAST. WHILE THERE HAS BEEN SOME CHANGES TO THE TRACK AND TIMING,
THE OVERALL STORY REMAINS THE SAME WITH HEAVY PRECIPITATION LIKELY
ACROSS SOUTHERN CALIFORNIA AND INTO NEVADA.
RADAR REFLECTIVITY CURRENTLY SHOWS LIGHT AND SCATTERED PRECIPITATION
ACROSS SOUTHERN CALIFORNIA WITH HEAVIER SHOWERS AND LIGHTNING OFF THE
BAJA COAST. PRECIPITATION WILL CONTINUE SPREADING ACROSS SOCAL
THROUGHOUT THE DAY TODAY BECOMING HEAVIER OVERNIGHT TONIGHT AND INTO
TOMORROW. CURRENT FORECASTS INDICATE THAT THE HEAVIEST AMOUNTS OF 4+
INCHES ARE LIKELY TO FALL ACROSS THE HIGHER ELEVATIONS OF THE
EASTERN TRANSVERSE AND PENINSULAR MOUNTAINS OF SAN BERNARDINO,
RIVERSIDE, AND SAN DIEGO COUNTIES. 1-2+ INCHES ARE CURRENTLY
FORECAST FOR LOWER ELEVATIONS ACROSS SAN DIEGO COUNTY AND INTO
SOUTHERN NEVADA. LIGHTER AMOUNTS ARE FORECAST FOR THE SIERRA WHERE
EASTERLY FLOW AROUND THE LOW AND THE UPPER TROF PROVIDE FORCING FOR
ASCENT. GIVEN THE CONVECTIVE NATURE OF TS RACHEL, LOCALLY HIGHER
AMOUNTS ARE LIKELY AT LOWER ELEVATIONS WHERE THUNDERSTORMS INITIATE
AND TRACK.
BY MONDAY...THIS DISTURBANCE WILL HAVE LIFTED OUT OF THE AREA TOWARD
THE NORTHERN ROCKIES. HOWEVER...THE SHARP UPR TROF THAT DUG
SOUTHWARD FROM BC AND THE PACIFIC NORTHWEST WILL SLOWLY MAKE ITS WAY
TO THE EAST. GIVEN THE CYCLONIC FLOW ALOFT AND PW VALUES BETWEEN
0.50- AND 0.75-INCH...LOOK FOR SCATTERED PRECIP TO CONTINUE OVER
PARTS OF THE SIERRA AND POINTS EASTWARD ACROSS NV...AS WELL AS NEAR
THE BASE OF THE UPR TROF FOR COASTAL SOUTHERN CA. WITH LESS
AVAILABLE MOISTURE IN PLACE...AMOUNTS WILL GENERALLY BE FROM 0.10-
TO 0.33-INCH.LERMAN
FOR THE MIDDLE OF THE UPCOMING WEEK...THE SYSTEM WILL FINALLY SHIFT
EAST OF THE AREA WITH PRECIP DISSIPATING ACROSS EASTERN NV THROUGH
TUESDAY. BY WEDNESDAY...AN OFFSHORE UPR RIDGE WILL SLIDE TOWARD THE
COAST BUILDING ACROSS THE WEST COAST BY THURSDAY INTO FRIDAY. THIS
WILL BRING DRYING WITH WARMING TEMPERATURES.
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
CWH
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