Graphic for MPD #0087
 
MESOSCALE PRECIPITATION DISCUSSION 0087
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
404 PM EDT FRI MAY 15 2015
 
AREAS AFFECTED...EASTERN WY, SOUTHWEST SD, & NORTHWEST NE 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 152003Z - 160203Z
 
SUMMARY...POTENTIAL FOR FLASH FLOODING TONIGHT IN AN AREA OF
SATURATED SOILS DUE TO RECENT SNOW MELT AND POTENTIAL FOR MULTIPLE
ROUNDS OF DEEP CONVECTION. 

DISCUSSION...WV/VISIBLE SATELLITE LOOPS SHOW THE EJECTING
ANOMALOUSLY STRONG NOSE OF THE 90+ KT JET LEAVING DISCUSSION AREA
WITHIN FAVORED DIVERGENCE ALOFT.  THIS FAVORS STRONG SFC
CYCLOGENESIS AND INCREASING LOW LEVEL FLOW/MOISTURE FLUX.  CURRENT
TPWS IN THE .8-1.0" RANGE WITH RAP GUIDANCE INCREASING TO 1.25" BY
02Z, NEAR THE LOWER THRESHOLD FOR RAIN RATES THAT WOULD LEAD TO
FLASH FLOODING IN THE REGION.  

AS INSTABILITY INCREASES AND THE WARM FRONT LIFTS
NORTHWARD...DISCRETE THUNDERSTORMS DEVELOPING OVER THE NEXT FEW
HOURS SHOULD FURTHER SATURATE ALREADY MOIST SOILS AHEAD OF A
BROKEN BAND OF THUNDERSTORMS FROM CO/WY WHICH WILL LIKELY COMPOUND
THE PROBLEM AND EXCEED THE LOW FLASH FLOOD GUIDANCE AS SUGGESTED
BY A SUITE OF MESOSCALE GUIDANCE.  EXPECTED MOISTURE IN THE REGION
SHOULD SUPPORT RAINFALL RATES UP TO 1.25" AN HOUR, OUTSIDE OF CELL
MERGERS.  THE THUNDERSTORM BAND, WITH EMBEDDED SUPERCELLS, SHOULD
GROW UPSCALE AND LIKELY SLOW DOWN AS IT APPROACHES THE 700 MB
NORTHWEST-SOUTHEAST ORIENTED DEFORMATION ZONE LAID OUT ACROSS NE
WY INTO SD...LIKELY COMPOUNDING RAINFALL TOTALS ALONG THIS
BOUNDARY.  THE MESOSCALE GUIDANCE ADVERTISES 2-4" LOCALLY,
PARTICULARLY IN THE BLACK HILLS AND BADLANDS OF SD.    


GALLINA/ROTH

ATTN...WFO...ABR...BOU...CYS...LBF...UNR...

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

LAT...LON   44490215 43720081 42500177 40910400 41000542 
            42010620 44190478 


Last Updated: 404 PM EDT FRI MAY 15 2015