MESOSCALE PRECIPITATION DISCUSSION 0439
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
557 PM EDT THU JUL 12 2018

AREAS AFFECTED...SOUTHEASTERN CA...WEST CENTRAL AZ...

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 122156Z - 130230Z

SUMMARY...STATIONARY CELLS CAPABLE OF 1-2" IN SHORT DURATION
DEVELOPING ALONG OUTFLOW BOUNDARIES CONTINUE TO POSE LOCALIZED
FLASH FLOODING CONCERNS THROUGH THE REMAINDER OF THE EVENING.

DISCUSSION...NUMEROUS SMALL CORE CONVECTIVE CELLS SCATTER THE
CENTRAL COLORADO RIVER VALLEY BACK TOWARD THE MOGOLLON RIM
DEVELOPING ALONG OUTFLOW BOUNDARIES FROM PRIOR CONVECTION SEEKING
OUT REMAINING WELLS OF INSTABILITY.  AT THIS TIME...INSOLATION
ACROSS THE MOJAVE DESERT INTO WEST CENTRAL AZ SUPPORT 90 TO 100F
TEMPS WITH TDS IN THE LOWER TO MID 60S ALLOWING FOR SBCAPES OF
1250 J/KG OVER THE MOJAVE TO 2000-2500 J/KG INTO THE SUN VALLEY. 
LPW AND RAP SOUNDINGS IN THE VICINITY SUGGEST FAIRLY SATURATED 8H
TO 5H LEVELS AIDING TPWS TO BE OVER 1.75" IN THE LOWEST ELEVATIONS
IN THE CENTRAL COLORADO RIVER VALLEY WITH SOLID 1.5" BELOW THE
MOGOLLON RIM. 

WHILE MEAN CLOUD MOTIONS REMAIN BELOW 10KTS SUPPORTING LOCALIZED
1-2" TOTALS WITHIN 30-60 MINUTES...STRENGTHENING COLD POOLS AND
INCREASED OUTFLOW WINDS MAY HELP TO REDUCE SOME SPOTS, BUT
COLLIDING OUTFLOWS MAY OVERTURN LARGER AREAS RAPIDLY FOR
STRONGER/QUICKER DOWNDRAFTS/RAIN RATES AS NIGHT FALLS.  THINKING
GREATEST RISK (HIGHER DENSITY OF CONVECTION) IS WITH THE GREATER
POOL OF INSTABILITY AND MOISTURE EAST OF THE COLORADO AND SOUTH OF
THE MOGOLLON RIM THROUGH 03Z...COMPARED TO MOJAVE DESERT...BUT
CANNOT RULE OUT SOME ISOLATED CELLS CAPABLE OF FF RAINS THERE AS
WELL. 

GALLINA

ATTN...WFO...FGZ...PSR...VEF...

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

LAT...LON   35631567 35121428 34791193 34271123 33611126
            33161186 33221286 33371345 33481399 33851501
            34491609 35471653