MESOSCALE PRECIPITATION DISCUSSION 0172
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
207 AM EDT SAT MAY 19 2018

AREAS AFFECTED...NORTHEAST CO...NE PANHANDLE...EXTREME SOUTHEAST
WY

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

VALID 190605Z - 191200Z

SUMMARY...ADDITIONAL HEAVY RAIN IS EXPECTED OVER THE NEXT SEVERAL
HOURS...WITH SOME LOCALLY FOCUSED CONCERNS FOR FLASH FLOODING.

DISCUSSION...RADAR IMAGERY SHOWS A RATHER PERSISTENT AXIS OF HEAVY
SHOWERS AND THUNDERSTORMS ACROSS THE NE PANHANDLE AND EXTENDING
SOUTH DOWN INTO FAR NORTHEAST CO.

THE CONVECTION REMAINS FOCUSED IN AN AREA OF RATHER STRONG LOW
LEVEL MOISTURE CONVERGENCE AND WITH EXCELLENT UPPER LEVEL
DIFFLUENCE AROUND THE NORTHEAST FLANK OF AN UPPER TROUGH AXIS THAT
EXTENDS FROM SOUTHWEST CO DOWN ACROSS NORTHEAST NM.
INSTABILITY ACROSS THE REGION IS BECOMING INCREASINGLY
EXHAUSTED...BUT THERE IS STILL A MODEST POOL OF 500 TO 1000 J/KG
OF MUCAPE THAT IS HELPING TO SUSTAIN THE CONVECTION.

OVER THE NEXT FEW HOURS...THE AFOREMENTIONED UPPER TROUGH AXIS
WILL BE PIVOTING UP TO THE NORTH IN A NEGATIVELY TILTED FASHION
THAT WILL FOSTER A BIT STRONGER LARGE SCALE ASCENT OVER THE
REGION. THIS SHOULD TEND TO COMPENSATE A BIT FOR THE WEAKENING
INSTABILITY PARAMETERS AND SHOULD ALLOW ONGOING CONVECTION TO TEND
TO PERSIST AT LEAST THROUGH 09Z. HOWEVER...THE CONVECTION IS
EXPECTED TO WEAKEN THEREAFTER GOING THROUGH 12Z AS THE WANING
THERMODYNAMICAL FIELDS BEGIN TO DOMINATE THE ABILITY TO SUSTAIN
CONVECTION.

ADDITIONAL RAINFALL AMOUNTS OF 2 TO 3 INCHES ARE SUPPORTED BY THE
LATEST HRRR GUIDANCE WHICH HAS RELATIVELY DECENT HANDLE OF THE
ONGOING CONVECTION. SOME RUNOFF PROBLEMS AND/OR FLASH FLOODING
WILL BE POSSIBLE GIVEN THE PERSISTENT NATURE OF THE CONVECTION.
WILL CONTINUE TO MONITOR.

ORRISON

ATTN...WFO...BOU...CYS...GLD...LBF...

ATTN...RFC...MBRFC...

LAT...LON   42120329 41980283 41340259 41060214 40640206
            40270234 40130306 40150344 40530411 41130430
            41610417 41980385