MESOSCALE PRECIPITATION DISCUSSION 0178
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
201 PM EDT SAT JUN 06 2015
 
AREAS AFFECTED...ELEVATED AREAS OF WY 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 061800Z - 070000Z
 
SUMMARY...THE COMBINATION OF ANOMALOUS MOISTURE AND A NEARBY
BOUNDARY COULD LEAD TO FLASH FLOODING, PARTICULARLY ACROSS TERRAIN
OF WY.

DISCUSSION...RAP FORECASTS ALONG WITH SURFACE ANALYSIS REVEAL A
BOUNDARY WHICH IS EXPECTED TO BE SLOW-MOVING ACROSS WY. 
PRECIPITABLE WATER VALUES (PWS) IN THE REGION ARE 0.75-1", WHICH
AT ELEVATION IS EQUIVALENT TO 1.50-1.75" PWS AT SEA LEVEL -- QUITE
MOIST.  RAP GUIDANCE SHOWS THE CAPE VALUES ACROSS THE REGION
EXCEEDING 1000 J/KG DURING THE AFTERNOON HOURS.  INFLOW INTO THE
REGION IS QUITE WEAK, BUT SO ARE THE VARIOUS CONVECTIVE
PROPAGATION VECTORS.  

STATIONARY THUNDERSTORMS ACROSS THE TOPOGRAPHY COULD BE CAPABLE OF
HOURLY RAIN RATES OF 1", WHICH WOULD EXCEED THE LOW FLASH FLOOD
GUIDANCE IN THIS RUGGED REGION.  THE 06Z SSEO NEIGHBORHOOD
PROBABILITIES OF EXCEEDING THE THREE HOUR FLASH FLOOD GUIDANCE ARE
QUITE ROBUST, SHOWING A SIGNIFICANT SIGNAL (ABOVE 90%) PERSISTING
IN THE MOUNTAINS BETWEEN 19Z TO BEYOND 00Z.  THE MESOSCALE
GUIDANCE GENERALLY ADVERTISED HIGHLY LOCALIZED MAXIMA OF 1-2" IN
THIS REGION.  FLASH FLOODING IS CONSIDERED POSSIBLE WITHIN
MOUNTAINOUS TERRAIN.

ROTH

ATTN...WFO...BYZ...CYS...PIH...RIW...TFX...

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

LAT...LON   45150802 44770721 44640709 44240692 43200663 
            42570586 42300629 42850760 43410866 43190906 
            42570870 42530927 43121007 42231047 42221089 
            43301106 43771109 44241097 44521116 44751040 
            45030971 44360907 44170826 44470778