Hydrometeorological Discussion
Issued by NWS California-Nevada RFC

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AGUS76 KRSA 281605
HMDRSA

HYDROMETEOROLOGICAL DISCUSSION
NATIONAL WEATHER SERVICE / CALIFORNIA NEVADA RFC / SACRAMENTO CA
805 AM PST WED JAN 28 2015

...PRECIP THU INTO FRI FOR SE CA AND FAR S NEV...
...NEXT SYSTEM ARRIVES NORTHERN TIER SUN INTO MON...

.24 HOUR PRECIPITATION TOTALS (ENDING JAN 28 AT 400 AM PST)...

LIGHT PRECIP FELL ACROSS MUCH OF THE SOUTHERN HALF OF CA AND MOST OF
NEVADA ON TUESDAY AS A LOW PRESSURE SYSTEM MOVED THROUGH THE REGION.
RAINFALL TOTALS ALONG THE SOUTHERN CA COAST WERE GENERALLY LESS THAN
0.1". PRECIP TOTALS IN THE SOUTHERN AND CENTRAL SIERRA RANGED FROM
ABOUT 0.1"-0.25". AMOUNTS OVER 0.5" WERE OBSERVED IN THE HIGH
TERRAIN IN EASTERN NEVADA.


.METEOROLOGICAL CONDITIONS (SHORT TERM: WED AM - SAT AM)...

SYSTEM FROM YESTERDAY HAS EXITED THE REGION...AND IS CURRENTLY
MOVING FROM THE NORTHERN/CENTRAL ROCKIES TOWARD THE GREAT PLAINS. IN
ITS WAKE...A WEAK TRANSITORY UPR RIDGE IS MOVING ACROSS CA THE
WESTERN US. FINALLY...JUST OFFSHORE THE CA COAST IS A WEAK UPR TROF
THAT EXTENDS SOUTH TOWARD 20N. CLOUDS ARE ALREADY STREAMING NNE
AHEAD OF THE SYSTEM AND MOVING ACROSS SOUTHERN CA.

THIS SYSTEM WILL SLOWLY MOVE TOWARD THE EAST...AND EVENTUALLY FORM A
CUTOFF LOW OVER THE LOWER COLORADO RIVER VALLEY TOWARD THE END OF
THE WEEK. PRECIP WITH THIS SYSTEM WILL BE CONFINED MAINLY TO EXTREME
SOUTHERN CA NE TOWARD EXTREME SOUTHERN NEV. THE EC HAS CONSISTENTLY
BEEN A BIT MORE WIDESPREAD WITH THE LIGHT PRECIP...WHILE THE
NAM/SREF HAS BEEN MORE SCATTERED...ESPECIALLY ON THURSDAY. THE GFS
IS MUCH MORE SCATTERED UNTIL FRIDAY WHEN PRECIP INCREASES AS WELL.
AT THIS TIME...BEST PRECIP WILL BE DOWNSTREAM OVER THE 4-CORNERS
STATES.


.METEOROLOGICAL CONDITIONS (LONG TERM: SAT AM - TUE AM)...

SHOWERS SHOULD BEGIN TO MOVE OUT OF SOUTHERN CA/NV EARLY SATURDAY AS
A LOW PRESSURE SYSTEM EXITS THE AREA AND MOVES SOUTH INTO MEXICO.
PRECIP TOTALS DURING THIS TIME LOOK TO BE LIGHT WITH SNOW
ELEVATIONS AROUND 7000FT.

IT IS BECOMING MORE CLEAR THAT A SYSTEM WILL IMPACT THE NORTHERN
HALF OF CA/NV EARLY NEXT WEEK. THE TIMING, INTENSITY, AND COVERAGE
OF THE PRECIP ARE IN FLUX AT THIS TIME. MODELS DO SHOW GOOD
AGREEMENT WITH A FRONTAL SYSTEM IMPACTING THE NORTH COAST OF CA BY
LATE SUNDAY NIGHT. THE GFS AND GEM KEEP PRECIP CONFINED TO THE NORTH
COAST WHILE THE ECMWF DRAGS THE PRECIP MUCH FURTHER SOUTH INTO THE
UPPER SAN JOAQUIN RIVER BASIN LATE SUNDAY. HAVE GONE WITH THE WETTER
SOLUTIONS OF THE GFS/GEM AND KEPT THE PRECIP NORTH OF THE I-80
CORRIDOR FOR SUNDAY/MONDAY AT THIS TIME. AS THE SYSTEM BEGINS TO
EXIT THE REGION, MODELS HAVE THE PRECIP PUSHING FURTHER SOUTH TO
NEAR THE I-80 CORRIDOR. LOCATIONS ALONG THE NORTH COAST MAY SEE SOME
APPRECIABLE RAINFALL TOTALS WITH THIS SYSTEM, BUT PRECIP ELSEWHERE
ACROSS NORTHERN CA/NV LOOKS TO BE ON THE LIGHT SIDE AT THIS TIME.


.HYDROLOGICAL CONDITIONS...

PRECIP THROUGH THE 5-DAY PERIOD WILL HAVE MINIMAL IMPACTS ON AREA
RIVERS. NO CRITICAL STAGES WILL BE REACHED THROUGH THE WEEKEND.


MORE INFORMATION ON THE CNRFC WEBSITE AT HTTP://WWW.CNRFC.NOAA.GOV

MI/DRK/MI/BW

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