MESOSCALE PRECIPITATION DISCUSSION 0397
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
502 AM EDT SAT SEP 27 2014
 
AREAS AFFECTED...CENTRAL AND NORTHERN UT...SOUTHEAST ID 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 270900Z - 271500Z
 
SUMMARY...LINEAR BANDS OF CONVECTION ARE EXPECTED OVER THE NEXT
SEVERAL HOURS WITH POTENTIAL FOR TRAINING. FLASH FLOODING WILL BE
POSSIBLE THROUGH THE EARLY MORNING HOURS.

DISCUSSION...THE LATEST IR SAT IMAGERY SHOWS A GENERAL TREND TWD
COOLING CLOUD TOPS OVER NRN UT AND SERN ID AS STRONG DEEP LYR
ASCENT ARRIVES OUT AHEAD OF THE DEEP TROUGH AND ASSOCD CLOSED LOW
MOVING ATTM THROUGH CNTRL CA. IN FACT...THE LATEST GOES OTD
ALGORITHM CONFIRMS A COUPLE OF OVERSHOOTING TOPS WITH THE ACTIVITY
JUST NORTHWEST OF THE GREAT SALT LAKE. RADAR IMAGERY ALREADY SHOWS
A COUPLE OF BKN N/S ORIENTED BANDS OF CONVECTION OVER CNTRL/NRN UT
WHICH IS EXPECTED TO ADVANCE INTO SERN ID OVER THE NEXT COUPLE
HOURS. THE ACTIVITY IS BEING AIDED BY ANOMALOUSLY MOIST DEEP SRLY
FLOW. INSTABILITY PARAMETERS ARE VERY WEAK...BUT THE MOISTURE
TRANSPORT WITHIN A STRONGLY FORCED COLUMN AND WITH OROGRAPHICS IS
HELPING TO DEVELOP AND SUSTAIN THE CONVECTION.

THE LATEST HIRES GUIDANCE INCLUDING THE 00Z NAM-CONEST...00Z ARW
AND 00Z NMMB ARE ALL TOO SLOW WITH THE ONGOING CONVECTION AND
LIKELY NOT QUITE INTENSE ENOUGH. THE CONVECTION OVER THE NEXT
SEVERAL HOURS SHOULD CONTINUE TO FOCUS OVER CNTRL/NRN UT AND
GRADUALLY ADVANCE INTO SERN NV WITH A LINEAR MODE CHARACTERIZED BY
FAST MOVING N/S ORIENTED BANDS. DEEP LYR FORCING SHOULD INCREASE A
BIT MORE THROUGH THE MORNING HOURS AND SO CONVECTION SHOULD BE
SUSTAINABLE AND CAPABLE OF REDEVELOPING AND TRAINING OVER THE SAME
AREA. REPEAT RAINFALL RATES OF UP TO 1 INCH/HR ARE POSSIBLE...AND
WITH OROGRAPHICS A CONCERN...SOME POTENTIAL EXISTS FOR FLASH
FLOODING THROUGH THE EARLY MORNING HOURS.

ORRISON

ATTN...WFO...PIH...SLC...

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

LAT...LON   43621264 43431131 41511111 39461112 38711152 
            38691243 39611279 40151317 40491351 41291356 
            42251342