MESOSCALE PRECIPITATION DISCUSSION 0077
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
213 AM EDT WED MAY 29 2013
 
AREAS AFFECTED...NORTHEAST CO...WESTERN NE 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 290607Z - 290900Z
 
SUMMARY...SLOW-MOVING COLD-TOPPED CONVECTION BECOMING BETTER
ORGANIZED OVER NORTHEAST CO AND WESTERN NE WITH LOCALIZED CELL
MERGERS AND REPEATING OF CONVECTION. SOME INCREASE IN FLASH FLOOD
POTENTIAL IS EXPECTED OVER THE NEXT COUPLE OF HOURS. 

DISCUSSION...A ROBUST MID LEVEL TROUGH ADVANCING INTO THE
INTERMOUNTAIN WEST IS PIVOTING GRADUALLY EAST INTO THE CNTRL
ROCKIES. STRONG DEEP LAYER ASCENT AFFORDED BY THE PRESENCE OF H25
RRQ JET DYNAMICS IS COUPLING WITH A MODERATELY UNSTABLE BOUNDARY
LAYER INVOF A STATIONARY FRONT TO SUSTAIN A FAIRLY STRONG MCS ATTM
OVER NERN CO AND WRN NE. MUCAPE VALUES AS PER THE LATEST RAP
ANALYSIS ARE ON THE ORDER OF 2000 TO 3000 J/KG OVER NWRN KS...NERN
CO AND SWRN NE...WITH A S/SELY LOW LEVEL JET THAT IS REACHING 40
TO 50 KTS ATTM UP THROUGH WRN KS. THE NOSE OF THIS JET IS
OVERRUNNING A STATIONARY FRONT DRAPED ACROSS THE REGION YIELDING
ENHANCED ISENTROPIC LIFT WHILE AIMED INTO THE SRN FLANK OF THE
MCS. THIS IS RESULTING IN A FAIRLY LARGE AXIS OF
BACKBUILDING/REPEATING CONVECTION. THE 00Z GLOBAL MODELS SUPPORT
SOME ADDITIONAL NOCTURNAL STRENGTHENING TO THE LOW LEVEL JET AFTER
06Z...AND THIS COUPLED WITH RELATIVELY MOIST/UNSTABLE BOUNDARY
LAYER SHOULD ACT TO SUSTAIN THE ONGOING CONVECTION FOR THE NEXT
SEVERAL HOURS. THE AFOREMENTIONED LARGE SCALE JET DYNAMICS WILL
ONLY ENHANCE THE POTENTIAL FURTHER. GIVEN THE SLOW MOVEMENT OF THE
MCS AND ESP WITH AN ENVIRONMENT FAVORABLE FOR BACKBUILDING
CONVECTION INCLUDING SOME CELL MERGERS...EXPECT THERE TO BE SOME
INCREASE IN FLASH FLOOD POTENTIAL OVER THE NEXT COUPLE OF HOURS.

ORRISON


ATTN...WFO...GID...LBF...GLD...BOU...CYS...

LAT...LON   40650473 41080433 41480351 41810257 42130056 41989943
            41609919 41249948 41020052 40780146 40440236 40120324
            39810412 39920469 40250485 40650473