MESOSCALE PRECIPITATION DISCUSSION 0165
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
224 AM EDT SAT JUL 20 2013
 
AREAS AFFECTED...SERN LOWER MI/NERN OH/NWRN PA INTO WRN NY 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 200612Z - 201015Z
 
SUMMARY...A SHARP THERMAL ZONE IS SLICING THROUGH THE GREAT LAKES
REGION TRIGGERING SEVERAL CONSOLIDATED LINES OF ACTIVE CONVECTIVE
HEAVY RAINFALL WITH SIGNS OF POSSIBLE TRAINING.

DISCUSSION...A SHARP THERMAL ZONE ACTING ON TREMENDOUS UPPER JET
DYNAMICS AND A NARROW BUT VERY ANOMALOUS MOISTURE ZONE IS
TRIGGERING SEVERAL LINES OF ACTIVE CONVECTION AND HEAVY RAINFALL.
TWO LINE SEGMENTS MOVED OFF LAKE ERIE EARLIER AND DISSIPATED
QUICKLY BUT MORE UPSTREAM ACTIVITY SEEM PRIME FOR POTENTIAL
TRAINING OVER THE NEXT SEVERAL HRS... AS PARTS OF ERIE/NIAGARA AND
ORLEANS IN WRN NEW YORK STATE SAW 2 TO 3.25 INCHES EARLIER AND IN
THE LAST THREE HRS KZO/BTL IN LOWER MI SAW 1.5 TO 1.8 INCHES VIA
MESONET DATA. 04Z ANALYSIS SHOWED A VERY NARROW ZONE OF 2 TO 2.25
INCH PWS WITH STEADY SWRLY/WSWRLY MOIST INFLOW AT 850MB...
FAVORABLE FOR HEAVY RAIN POTENTIAL. ADD IN THAT FROM 06Z TO 09Z
ALL OF THE GLOBAL MODELS FAVOR RIGHT HAND ENTRANCE REGION UPPER
JET DYNAMICS AT 250MB IN THIS VICINITY AND THESE MULTIPLE LINES
COULD FORM INTO ONE SOLID ONE. 1 HR FFG IS GENERALLY AROUND 2
INCHES OR GREATER WITH SLIGHTLY LOWER NUMBERS IN NERN OH/SERN LWR
MI AND NWRN PA OF 1.5 INCHES... THUS WILL HIGHLIGHT THE ENTIRE
REGION FOR LOCALIZED FLASH FLOODING POTENTIAL.

MUSHER

ATTN...WFO...BGM...BUF...CTP...PBZ...CLE...DTX...IWX...GRR...

ATTN...RFC...MARFC...NCRFC...NERFC...OHRFC...

LAT...LON   41537654 41077829 40457982 40688170 41048332 41408422
            41738493 42318528 42298397 42418190 42717993 43347854
            42677595 42167550 41537654