MESOSCALE PRECIPITATION DISCUSSION 0461
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
612 PM EDT SUN JUL 15 2018

AREAS AFFECTED...PORTIONS OF CENTRAL/SOUTHERN CO INCLUDING THE
FRONT RANGE AND PALMER DIVIDE

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

VALID 152210Z - 160200Z

SUMMARY...SHOWERS AND THUNDERSTORMS MAY BECOME A BIT MORE
CONCENTRATED OVER THE NEXT COUPLE OF HOURS. SLOW CELL MOTIONS AND
HEAVY RAINFALL RATES MAY RESULT IN SOME FLASH FLOODING.

DISCUSSION...THE LATEST SURFACE OBSERVATIONS SHOW A COLD FRONT
SETTLING SOUTH DOWN THE FRONT RANGE OF CO. NORTHEAST LOW LEVEL
FLOW BEHIND THE BOUNDARY IS FOCUSING A MOIST AND RELATIVELY
UNSTABLE BOUNDARY LAYER INTO THE EASTERN SLOPES OF THE FRONT RANGE
INCLUDING THE PALMER DIVIDE WHICH IS ALLOWING FOR SOME SLOW-MOVING
AND HEAVY SHOWERS AND THUNDERSTORMS TO FOCUS OVER THE REGION. THE
CONVECTION IS ALSO FOCUSING NEAR AN AREA WHERE THERE IS AT LEAST
MODESTLY FAVORABLE RIGHT-ENTRANCE REGION UPPER LEVEL JET DYNAMICS.

OVER THE NEXT FEW HOURS...THERE WILL BE RATHER FAVORABLE UPSLOPE
INTO THE EAST-FACING SLOPES OF THE TERRAIN ACROSS PORTIONS OF
CENTRAL AND SOUTHERN CO. THIS COUPLED WITH LINGERING INSTABILITY
AN ANOMALOUSLY MOIST COLUMN WILL PROMOTE SHOWERS AND THUNDERSTORMS
WITH LOCALLY VERY HEAVY RAINFALL RATES. IN FACT...PWATS ACROSS THE
REGION ARE RUNNING 2 TO 3 STANDARD DEVIATIONS ABOVE NORMAL WITH
THE AID OF MID AND HIGH LEVEL MONSOONAL MOISTURE...AND THIS WILL
PROMOTE EFFICIENT RAINFALL PROCESSES.

EXPECT AT LEAST LOCALLY AS MUCH AS 2 TO 3 INCHES OF RAIN THROUGH
EARLY EVENING...WHICH WILL RESULT IN SOME POTENTIAL FOR FLASH
FLOODING. THE GREATEST AREA OF CONCERN WILL BE THE MORE SENSITIVE
BURN SCAR AREAS OVER THE TERRAIN.

ORRISON

ATTN...WFO...BOU...PUB...

ATTN...RFC...ABRFC...MBRFC...WGRFC...

LAT...LON   39950531 39870453 38650436 37330453 37040481
            37000540 37340576 38030565 38590570 39220572