Graphic for MPD #0005
MESOSCALE PRECIPITATION DISCUSSION 0005
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
331 PM EST WED JAN 04 2017
 
AREAS AFFECTED...CENTRAL CALIFORNIA 
 
CONCERNING...HEAVY RAINFALL 
 
VALID 042030Z - 050800Z
 
SUMMARY...CONTINUED LONG DURATION MOISTURE FLUX WITH LOWER
ELEVATION PERSISTENT MODERATE RAINFALL LEAD TO AN ADDITIONAL 3-5"
RAINS IN FAVORED OROGRAPHY. 

DISCUSSION...IN THE SHORT TERM A SMALL SLUG OF INCREASED MOISTURE
(TPW TO 1.4") ALONG E-W LINE OF INCREASE SFC MOISTURE CONVERGE IS
MAXIMIZED ALONG COASTAL RANGE AND JUST OFFSHORE KSBP.  RECENT
ANALYSIS INDICATES MODERATE SURFACE FLOW WITH WINDS TO 25KTS WITH
NEARLY 60-70 DEGREES OF SOUTHERLY SFC CONVERGENT FLOW THEN ASCENDS
FAIRLY RAPIDLY AND VEERS TO DUE WESTERLY IN A NARROW CORRIDOR
AFFECTING SAN LUIS OBISPO COUNTY INTO N SANTA BARBARA COUNTY INTO
NEARLY PERPENDICULAR OROGRAPHICS.  RATES OF .25-.4"/HR WILL
CONTINUE AS THIS ZONE CONTINUES TO DROP SOUTH.  CONFLUENCE OF
REDUCING LOW LEVEL INFLOW AS WELL AS PERPENDICULAR OROGRAPHICS
WILL START TO WANE TOWARD 23-00Z REDUCING THE THREAT.

SIERRA FOOTHILLS...
WV LOOP SHOWS WELL DEVELOPED UPPER LEVEL LOW WELL WEST OF 140W
THOUGH PROVIDES BROAD SWLY INFLUENCE THAT CONTINUES TO TAP
SUBTROPICAL MOISTURE FEED. A SHORTWAVE/JET SPEED MAX WITHIN THE
SOUTHWESTERLY FLOW AS REACH THE APEX OF LARGER SCALE SE-NW RIDGING
NEAR 38N130W.  THESE WEAK HEIGHT FALLS ARE SUPPORTING STRONGER
ISENTROPIC ASCENT OF THE SUBTROPICAL MOISTURE THAT WITH MODERATE
RAIN SHOWER ACTIVITY AND SOME ELEVATED INSTABILITY NORTHEAST. 
THOUGH THE SHORTWAVE WILL FLATTEN AND SHEAR INTO THE DEEPER
WESTERLY FLOW AND REDUCE THE MOISTURE/INSTABILITY CHANNEL...THE
AFFECTS WILL OVERRUN THE BAY AREA LIKELY AT HIGH ENOUGH ELEVATION
WITH DRIER LOWER LEVEL TO NOT LEAD TO APPRECIABLE RAINFALL ON THE
COAST RANGE.  HOWEVER...THE TRANSPORT OF 850-7H TPWS OF UP TO
.5"-.6" WILL ADVECT ON 20-30 KT FLOW AND ASCEND RAPIDLY ALONG THE
LOWER FOOTHILLS OF THE CENTRAL SIERRAS WITH RATES UP TO .25"/HR
FOR 6-10 HRS WITH AN ADDITIONAL 1-2.5" OF RAIN IN ELEVATIONS BELOW
7K FT (SNOW ABOVE).  

FURTHER SOUTH TOWARD MORE N-S ORIENTED TOPOGRAPHY OF TULARE/N KERN
COUNTY WILL BE A BIT WARMER/MORE MOIST WITH BETTER ORTHOGONAL FLOW
SUPPORTING RATES OVER .3"/HR. THEREFORE TOTALS OF 3-4" ARE LIKELY
WITH SOME ISOLATED 5-6" TOTALS POSSIBLE COMPOUNDING FLOODING
CONCERNS.  THIS ALIGNS WELL WITH CURRENT PREFERENCES TOWARD THE
HI-RES CAMS LIKE THE WRF-ARW AND THE HRRR-EXP. 

GALLINA

ATTN...WFO...HNX...LOX...MTR...STO...

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

LAT...LON   38532005 38171975 37731941 36921875 36201831 
            35621817 35181841 34851885 34601971 34652037 
            35322099 36122159 35762091 35442047 35032011 
            34931951 35101889 35361885 36361899 36921945 
            37732009 38252053 38302049 38522037 


Last Updated: 331 PM EST WED JAN 04 2017