MESOSCALE PRECIPITATION DISCUSSION 0452
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
528 AM EDT MON JUL 11 2016
 
AREAS AFFECTED...CENTRAL AND EASTERN MT 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 110930Z - 111430Z
 
SUMMARY...DEVELOPING CONVECTION OVER CENTRAL AND EASTERN MT COULD
PRODUCE HOURLY RAINFALL RATES NEAR AN INCH THROUGH 15Z. THIS MAY
RESULT IN LOCALIZED FLASH FLOODING IN AREAS OF LOW FLASH FLOOD
GUIDANCE.

DISCUSSION...CONVECTION IS EXPANDING ACROSS PORTIONS OF NORTH
CENTRAL MT EARLY THIS MORNING...IN A POCKET OF 250 J/KG OF MUCAPE.
PRECIPITABLE WATER VALUES RANGE BETWEEN 0.75 AND 1.00 INCHES (PER
THE LATEST RAP ANALYSIS)...AND KGGW RADAR INDICATED HOURLY
RAINFALL RATES NEAR AN INCH OVER PHILLIPS AND GARFIELD COUNTIES. 

AS AN UPPER LOW CROSSES CENTRAL AND EASTERN MT THIS
MORNING...LOWERING HEIGHTS SHOULD RESULT IN BETTER
INSTABILITY...AS THE CAPPING IN PLACE IS ERASED. THE LATEST RAP
SUGGESTS MUCAPE VALUES COULD TOP OUT BETWEEN 250 AND 500 J/KG
ACROSS PORTIONS OF CENTRAL AND NORTHEAST MT...AND BASED ON THE
CURRENT RADAR PRESENTATION...THESE INSTABILITY VALUES SHOULD BE
SUFFICIENT TO SUPPORT ADDITIONAL CONVECTION THIS MORNING. 

AHEAD OF THE MID LEVEL TROUGH...BOTH THE STEERING CURRENT AND
CORFIDI VECTORS DROP BELOW 10 KNOTS BETWEEN 12Z AND 15Z...
ESPECIALLY ACROSS EAST CENTRAL MT. THE WEAK STEERING FLOW COULD
RESULT IN SLOW MOVING CELLS. THE LATEST HRRR/HRRR PARALLEL SUGGEST
THAT HOURLY RAINFALL RATES NEAR AN INCH ARE POSSIBLE... ESPECIALLY
WHERE CELL MERGERS AND LOCAL BACKBUILDING CAN OCCUR. 

ONE HOUR FLASH FLOOD GUIDANCE VALUES ARE UNDER AN INCH IN PORTIONS
OF CENTRAL AND EASTERN MT...AND SLOW MOVING CELLS COULD PRODUCE
RAINFALL AMOUNTS EXCEEDING THESE VALUES. THE LATEST HRRR/HRRR
PARALLEL INDICATE LOCAL 2.00 INCH RAINFALL AMOUNTS...AND GIVEN
SLOW CELL MOVEMENTS AND BOTH CELL MERGERS/BACKBUILDING...FLASH
FLOODING IS CONSIDERED POSSIBLE THIS MORNING.

HAYES

ATTN...WFO...BYZ...GGW...TFX...

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

LAT...LON   49420683 48780519 47330519 46900600 46840638 
            46710741 45890898 45850986 46461016 47161014 
            47851019 48171024 48201021 49150981