AGUS76 KRSA 151623 HMDRSA HYDROMETEOROLOGICAL DISCUSSION NATIONAL WEATHER SERVICE / CALIFORNIA NEVADA RFC / SACRAMENTO CA 930 AM PDT TUE APR 15 2008 ...COLD TROUGH MOVING EAST.. .24 HOUR PRECIPITATION TOTALS (ENDING APR 15 AT 500 AM PDT)... HIGHEST ONE TO TWO TENTHS AMOUNTS WERE RECORDED OVER THE UPPER KLAMATH, MAD, AND EEL BASINS, AND PIT IN SHASTA CO. LESS THAN A TENTH OF AN INCH FELL ACROSS THE SMITH, LOWER EEL, UPPER RUSSIAN, SHASTA DRAINAGE, AND THE SIERRA AS FAR SOUTH AS I-80. .METEOROLOGICAL CONDITIONS... COLD FRONT PASSING THROUGH THE CNRFC THIS MORNING WILL PRODUCE A FEW LIGHT SNOW SNOWERS OVER FAR NORTHERN SITES. RETURNS THIS MORNING OVER THE SIERRA AS FAR SOUTH AS BLU. A VORTICITY MAX ROUNDS THE BASE INTO NV THIS AFTERNOON. MODIFIED HPC QPF BY ADDING LIGHT PRECIP TO ACCOMPANY THE TROUGH PASSAGE, BUT LESS THAN ONE OR TWO HUNDRETHS IN ANY GIVEN PERIOD. TIME-HEIGHT ANALYSIS SHOWS THE MOISTURE WILL BE SHALLOW, BUT ADDED A LITTLE OVER THE TRUCKEE BASIN, AND NORTHERN NV. VIRTUALLY DRY EVERYWHERE ELSE, WITH THE EXCEPTION OF FAR SOUTHERN OREGON. UNTIL THE FLOW BECOMES OFFSHORE 12Z WEDS, THERE WILL STILL BE COOL, MOIST CONDITIONS OVER THE CASCADES. DAY 1 QPF (TUE 15/12Z TO WED 16/12Z): LESS THAN A TENTH OVER CASCADES, TRUCKEE BASIN AND NORTHERN NV. DAY 2 QPF (WED 16/12Z TO THU 17/12Z): DRY DAY 3 QPF (THU 17/12Z TO FRI 18/12Z): DRY .HYDROLOGICAL CONDITIONS... COOLER TEMPERATURES OBSERVED YESTERDAY AND FORECAST FOR TODAY ARE EXPECTED TO SLOW EARLY SNOWMELT AND CAUSE HYDROGRAPHS TO FALL BACK TOWARD BASEFLOW LEVELS. WARMER TEMPERATURES THAT WERE OBSERVED OVER THE PAST WEEKEND HAD INDUCED SMALL RISES ON RIVERS IN THE SIERRA NEVADA AND NORTH COASTAL RANGES. ALL FORECAST POINTS ARE EXPECTED TO REMAIN WELL BELOW MONITOR LEVELS. MORE INFORMATION ON THE CNRFC WEBSITE AT HTTP://WWW.CNRFC.NOAA.GOV EL/AH $$ |