010  
AWUS01 KWNH 080126  
FFGMPD  
MTZ000-080700-  
 
MESOSCALE PRECIPITATION DISCUSSION 0443  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
925 PM EDT WED JUN 07 2023  
 
AREAS AFFECTED...NORTHEASTERN QUADRANT OF MT  
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY  
 
VALID 080120Z - 080700Z  
 
SUMMARY...AREAS OF FLASH FLOODING APPEAR LIKELY TO CONTINUE FOR  
PORTIONS OF THE NORTHEASTERN QUADRANT OF MT THROUGH 04Z, WITH A  
POSSIBLE THREAT CONTINUING BEYOND 04Z. RAINFALL RATES OF 1-2  
INCHES IN 30-60 MINUTES ARE EXPECTED.  
 
DISCUSSION...REGIONAL RADAR IMAGERY OVER EASTERN MT AT 01Z SHOWED  
SCATTERED THUNDERSTORMS FOCUSED OVER EAST-CENTRAL MT, BETWEEN I-94  
AND JUST NORTH OF THE MISSOURI RIVER NEAR FORT PECK LAKE. WHILE  
THE PRESENCE OF HAIL MAY BE CAUSING MRMS-RAINFALL ESTIMATES TO BE  
A BIT TOO HIGH, MRMS SUGGESTS 1-2 INCHES IN 30 TO 60 MINUTES HAS  
OCCURRED WITH SOME OF THE STRONGER CELLS OVER THE PAST FEW HOURS.  
NUMEROUS OUTFLOW BOUNDARIES WERE OBSERVED ON KGGW RADAR IMAGERY,  
SURGING TOWARD THE WEST AND ABOUT TO CONVERGE IN THE VICINITY OF  
THE PHILLIPS/GARFIELD COUNTY LINE. MLCAPE NEAR 850 J/KG WAS  
OBSERVED ON THE 00Z GGW SOUNDING ALONG WITH 1.2 INCHES OF PW (NEAR  
CLIMATOLOGICAL MAX FOR JUNE 7/8) AND 7 C/KM 700-500 MB LAPSE  
RATES. SPC MESOANALYSIS DATA FROM 01Z SHOWED LOCALLY HIGHER CAPE  
(1000+ J/KG) OVER PORTIONS OF NORTHEASTERN MT.  
 
A SHORT TERM FLASH FLOOD THREAT WILL CONTINUE WHERE STORMS ARE IN  
THE PROCESS OF MERGING WITH A FLARE UP OF CONVECTION LIKELY AS NEW  
UPDRAFTS FORM WITHIN THE AREA OF ENHANCED SURFACE CONVERGENCE.  
EASTERLY/UPSLOPE FLOW TO THE IMMEDIATE EAST OF THIS REGION WILL  
HELP TO SUSTAIN WIDELY SCATTERED CONVECTION IN THE SHORT TERM AS  
WELL GIVEN THE LINGERING INSTABILITY. CONTINUED AND LOCALLY  
ENHANCED LOW LEVEL EASTERLY WINDS MAY CONTINUE A LOCALIZED FLASH  
FLOOD THREAT TO THE EAST AND SOUTHEAST OF THE EXPECTED DISSIPATION  
OF MERGING CELLS (LOCATED TO THE WEST) LATER IN THE OVERNIGHT. LOW  
FLASH FLOOD GUIDANCE VALUES OF ABOUT 1 INCH (1 AND 3 HOUR  
DURATION) ARE FAIRLY WIDESPREAD ACROSS THE DISCUSSION AREA,  
CONTRIBUTING TO THE LIKELIHOOD OF ADDITIONAL FLASH FLOODING IN THE  
SHORT TERM. RAINFALL RATES OF 1-2 INCHES IN 30-60 MINUTES WITH  
ADDITIONAL STORM TOTALS OF 3 OR 4 INCHES ARE EXPECTED THROUGH 07Z.  
 
OTTO  
   
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
 
 
ATTN...WFO...BYZ...GGW...TFX...  
 
ATTN...RFC...MBRFC...NWC...  
 
LAT...LON 49020952 49010843 48990694 48820659 48480631  
47050553 46300533 46030579 46090664 46240725  
46460770 46890847 47540938 47740959 48690978  
 
 
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