MESOSCALE PRECIPITATION DISCUSSION 0513
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
420 PM EDT SUN JUL 22 2018

AREAS AFFECTED...SOUTHERN WY...NORTHWEST CO...EXT SOUTHEAST
ID....NORTHEAST UT...

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

VALID 222019Z - 230200Z

SUMMARY...DEEP MOISTURE SLUG CROSSING OROGRAPHICS TOWARD BETTER
INSTABILITY WILL INCREASE CONVECTIVE RAINFALL EFFICIENCY AND POSE
POSSIBLE FLASH FLOODING THIS AFTERNOON INTO EVENING. 

DISCUSSION...GOES-16 WV SUITE DEPICT AN ELONGATING/SHEARING VORT
CENTER(S) ROUNDING THE NORTHWEST EDGE OF THE SYNOPTIC RIDGE
CENTERED IN NM AS IT EXPANDS TO THE WEST. CIRA LAYERED PW AND
OVERALL BLENDED TPW LOOPS SHOW A SLUG OF DEEPER MOISTURE LAGGING
THE LEADING SHORTWAVE HEIGHT-FALLS BUT AHEAD OF THE TAIL END OF
THE SHEAR AXIS ACROSS NE NV INTO NORTHERN AND CENTRAL UT. FROM
THIS SLUG OF MOISTURE THERE IS MEAN CONFLUENT FLOW MID-LEVEL FLOW
ASCENDING INTO THE RIGHT ENTRANCE REGION OF THE EXITING 90KT JET
OVER NE MT ATTM.  AS SUCH, STRENGTHENED OROGPRAHIC ASCENT ACROSS
THE CARIBOU AND MONTE CRISTO RANGES OF SE ID/N UT IN THE
CONFLUENCE AND SOME MODERATE MID-LEVEL LAPSE RATES/MUCAPES HAVE
SPARKED A BROAD AREA OF CBS SEEN IN VISIBLE IMAGERY EXPANDING INTO
SW WY.  THE FOCUS WILL SLOWLY SHIFT SOUTHEAST AND BEGIN TO SUPPORT
DEVELOPMENT ACROSS THE UNITA RANGE AS WELL AND GIVEN PERSISTENT
LOW LEVEL MST FLUX FROM SWLY FLOW OUT OF SW UT...BACKBUILDING OR
UPSTREAM REDEVELOPMENT IS ALSO EXPECTED TO HELP ADD TO THE THREAT
OF LOCALIZED FLASH FLOODING.

TOTAL PWS NEARING 1" ARE EXPECTED TO EXCEED 1" TOWARD
00Z...ALLOWING FOR MORE EFFICIENT RAINFALL. UPSTREAM CLEARING
ACROSS NW CO/SOUTH CENTRAL WY WILL CONTINUE TO SUPPORT AND
INCREASE OF INSTABILTY IN ADVANCE OF THE MAIN FORCING TO HELP
STRENGTHEN THE UPDRAFTS AND INCREASE RAINFALL EFFICIENCY FROM
.75"/HR TO 1-1.25"/HR WHICH IS IN THE VICINITY OF 1HR FFG VALUES
SUGGESTING FLASH FLOODING IS POSSIBLE THIS AFTERNOON INTO EVENING.

GALLINA

ATTN...WFO...BOU...CYS...GJT...PIH...RIW...SLC...

ATTN...RFC...CBRFC...MBRFC...NWRFC...

LAT...LON   42951039 42170826 41850682 41350617 40870584
            40460593 39900640 39910696 39850771 39620925
            39840995 39691132 40811118 41231123 41931159
            42701143 42941072