MESOSCALE PRECIPITATION DISCUSSION 0689
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
152 PM EDT THU SEP 22 2016
 
AREAS AFFECTED...EASTERN UT...NORTHWEST CO...SOUTHWEST WY 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 221752Z - 222152Z
 
SUMMARY...DEEP UNIDIRECTIONAL FLOW ALONG TROPICALLY CONNECTED
MOISTURE AXIS CONTINUES TO POSE FLOODING AND FLASH FLOODING THREAT.

DISCUSSION...GOES-W WV LOOP CONTINUES TO SHOW BROAD DIFFLUENCE
COINCIDENT WITH SSW-NNE MOISTURE TRANSPORT WITHIN WARM CONVEYOR
BELT ACROSS E UT TOWARD NW CO/SW WY.  ADDITIONALLY THE DEEP MST
FLOW HAS BEEN INTERSECTING FAVORABLY ORIENTED OROGRAPHICS THAT
HAVE BEEN ENHANCING ASCENT AS WELL.  DEEP MOISTURE CHANNEL WITH
TPWS NEAR OR ABOVE 1.25" EXIST ALONG WITH MARGINAL LAPSE RATES AND
GIVEN SUFFICIENT FORCING SUPPORTS CONVECTIVE DEVELOPMENT THROUGH
THE CONVEYOR BELT.  THE BREADTH OF THE LINE GENERALLY LARGER
NEARER THE SHORTWAVE TROF AXIS THAT HAS BEEN LIFTING THROUGH THE
SSWLY FLOW CURRENTLY EXTENDING FROM NEAR KELY NV ACROSS SALT LAKE
INTO THE UINTA RANGE. STILL THOUGH THE LINE NARROWS FURTHER
SOUTH...VISIBLE IMAGERY ALONG WITH LIGHTNING NETWORK STILL
INDICATES THE POTENCY OF CONVECTION CAPABLE OF RATES UP TO .75"/HR
RANGE. RATES AND TOTALS ARE  NEAR .75-1.0" REMAIN POSSIBLE IN AN
HOUR WITHIN E UINTA RANGE AND BOOK CLIFF RANGES OVER THE NEXT FEW
HOURS.  GIVEN COMPLEX TERRAIN AND LOW FF GUIDANCE VALUES THIS
SUGGESTS THE THREAT OF FLASH FLOODING STILL EXISTS IN THE NEAR
TERM.  THIS SCENARIO IS SUPPORTED BY RECENT 12Z ARW AND RECENT
RUNS OF THE HRRR AND ESRL EXPERIMENTAL HRRR WITH ADDITIONAL 1-2"
TOTALS POSSIBLE  

AS CLOUDS BREAK BECOME LESS NUMEROUS...SOME INCREASE INSOLATION
OVER CENTRAL/EASTERN UT MAY INCREASD INSTABILITY WITH INVIGORATION
OF CONVECTIVE DEVELOPMENT THROUGH THE AFTERNOON HOURS (21-22Z)
PRESENTING AN ADDITIONAL ROUND OF RAINFALL POTENTIALLY COMPOUNDING
ANY ONGOING FLOODING CONCERNS AS WELL AND MAY NEED TO REASSESS THE
SITUATION FOR FURTHER MPD GUIDANCE.   

GALLINA

ATTN...WFO...CYS...GJT...RIW...SLC...

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

LAT...LON   42430898 42340813 41530762 40060817 38140983 
            37801095 38181146 39811121 40951055