MESOSCALE PRECIPITATION DISCUSSION 0024
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
844 AM EST SUN JAN 31 2016
 
AREAS AFFECTED...SOUTHERN CALIFORNIA 
 
CONCERNING...HEAVY RAINFALL 
 
VALID 311344Z - 010144Z
 
SUMMARY...A QUICK MOVING SYSTEM WITH MODERATE RAIN RATES TO LEAD
TO SOME FLOODING CONCERNS MAINLY IN OROGRAPHY AND BURN SCARS. 

DISCUSSION...WV/IR LOOP SHOWS A COMPACT WAVE WITH AN IMPRESSIVE
BAROCLINIC LEAF INDICATIVE OF GOOD DIFFLUENCE AND ASSOCIATED
LARGER SCALE ASCENT JUST SHIFTING INTO CENTRAL CALIFORNIA COAST. 
BLENDED TPW SHOWS A SLUG OF 1.2-1.3" TPWS WITHIN THE AMPLIFYING
WARM SECTOR.  THE 1042Z AMSU PASS ALSO INDICATED AN EXPANDING AREA
OF RAIN RATES IN EXCESS OF .3"/HR ALREADY WITHIN THIS WARM SECTOR.
A THE SURFACE THE WARM FRONT IS BEGINNING TO LIFT OUT NEAR SANTA
BARBARA TOWARD SAN LUIS OBISPO USHERING IN SOUTHERLY AND
SOUTHWESTERLY LOW LEVEL FLOW ACROSS THE DISCUSSION AREA WITH WINDS
FROM 20-25 KTS INCREASING TO 30-35 KTS WITH ISOLATED 50 WESTERLY
FLOW JUST AHEAD OF THE COLD FRONT MOVING THROUGH THE CHANNEL
ISLANDS BY MIDDAY.  THIS PROVIDES EXCELLENT MOISTURE FLUX INTO THE
SOUTH AND WEST FACING OROGRAPHY ACROSS MUCH OF SOUTHERN
CALIFORNIA...ALLOWING FOR INCREASED MODERATE RAIN SHOWERS AHEAD OF
THE STRONGER STORMS NEAR THE TRIPLE POINT AND ALONG THE COLD
FRONT.  GIVEN TPWS OF 1.2" INCREASING ISALLOBARIC FLOW FROM
DEEPENING SURFACE CYCLONE AND ADDITIONAL ASCENT NEAR
OROGRAPHY..EXPECTING RAIN RATES NEAR OR IN EXCESS OF 1"/HR NEAR
THE TRIPLE POINT/SURFACE LOW THAT SHOULD TRACK NEAR OR JUST NORTH
OF THE SPINE OF HIGHER ELEVATION OF THE SAN EMIGDIO/SAN GABRIEL
INTO SAN BERNADINO MTNS THOUGH 22-23Z EVENTUALLY SHIFTING FOCUS OF
MORE WSWLY FLOW INTO THE SAN JACINTO AND SANTA ANA RANGES AND
(SOUTHWARD).   THE POSITIVE NOTE WOULD BE THE RELATIVE SPEED OF
THE RAINFALL...NOT ALLOWING EXTREME COMPOUNDING OF TOTALS. 
HOWEVER...EXPECTATION IS FOR TOTALS IN THE 1.5-2.0" RANGE ALONG
THE COASTAL TERRAIN EAST AND SOUTH OF SAN LUIS OBISPO AND ALONG
THE HIGHEST ELEVATIONS ALONG THE SOUTH FACING SPINE OUT TO THE SAN
BERNADINO MTNS.  CURRENTLY THE RECENT HRRR RUN AND WRF-NSSL APPEAR
MOST IN LINE WITH CURRENT THINKING WITHIN THE HI-RES CONVECTIVE
ALLOWING MODELS. ISOLATED POCKETS UP TO 2.5" MAY NOT BE OUT OF THE
QUESTION BUT SEEM A BIT LESS LIKELY GIVEN DURATION PER WRF-ARW.

GALLINA  

ATTN...WFO...HNX...LOX...SGX...VEF...

ATTN...RFC...CNRFC...

LAT...LON   35602072 35542041 35202005 35021972 35021916 
            35021885 35391852 35371823 35141813 34751833 
            34601790 34601755 34441703 34231665 33671647 
            33071624 32781634 32651692 32951718 33451753 
            33901829 34131904 34401997 34622065 35332119 
            35542119