MESOSCALE PRECIPITATION DISCUSSION 0218
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
502 PM EDT MON MAY 28 2018

AREAS AFFECTED...SOUTH-CENTRAL TO SOUTHEAST WY...NORTH-CENTRAL TO
NORTHEAST CO...PANHANDLE OF NE

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

VALID 282100Z - 290300Z

SUMMARY...SLOW-MOVING SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
EXPAND IN COVERAGE OVER THE NEXT FEW HOURS. FLASH FLOODING IS
POSSIBLE.

DISCUSSION...THE LATEST RADAR AND SATELLITE IMAGERY SHOWS
SLOW-MOVING SHOWERS AND THUNDERSTORMS DEVELOPING AND EXPANDING IN
COVERAGE FROM NEAR THE FRONT RANGE OF CO UP ACROSS SOUTH-CENTRAL
WY.

THE CONVECTION IS FOCUSING WITH THE AID OF STRONG DIURNAL HEATING
AND CLOSE PROXIMITY OF A FRONT WHICH IS FOCUSING RELATIVELY MOIST
LOW LEVEL UPSLOPE FLOW ACROSS THE IMMEDIATE HIGH PLAINS AND EAST
SLOPES OF THE CENTRAL ROCKIES. THE ACTIVITY IS ALSO EMBEDDED
WITHIN DEEP LAYER CYCLONIC FLOW WITH STEEPENING MID LEVEL LAPSE
RATES ASSOCIATED WITH AN UPPER TROUGH/CLOSED LOW EJECTING SLOWLY
NORTHEAST ACROSS THE INTERMOUNTAIN REGION. THIS IS CONTRIBUTING TO
MODERATE TO STRONG INSTABILITY OVER THE CO HIGH PLAINS WHERE
MLCAPE VALUES ARE ON THE ORDER OF 1000 TO 2000+ J/KG.

CONVECTION WILL CONTINUE TO DEVELOP AND EXPAND IN COVERAGE GOING
TOWARD THE EVENING HOURS...AND THE LATEST HIRES MODEL CONSENSUS
SHOWS AN EASTWARD PUSH OF HEIGHT FALLS/FORCING THAT SHOULD ALLOW
CONVECTION TO DEVELOP EAST OUT ACROSS THE HIGH PLAINS AND INTO THE
AFOREMENTIONED INSTABILITY AXIS.

RAINFALL RATES OF 1.5 INCHES/HR ARE EXPECTED WITH STORM TOTALS
GOING THROUGH 03Z OF AS MUCH AS 2 TO 4+ INCHES WITH THE AID OF
SLOW CELL MOTION. FLASH FLOODING WILL BE POSSIBLE AS A RESULT.

ORRISON

ATTN...WFO...BOU...CYS...GJT...GLD...PUB...RIW...

ATTN...RFC...ABRFC...CBRFC...MBRFC...

LAT...LON   42790751 42400505 41700364 40940275 40190236
            38930252 38460296 38260343 38180409 38200457
            38500526 39010583 39390606 40180632 40640680
            41010754 41060941 41370996 41871000 42310964
            42650891