EXCESSIVE RAINFALL DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 1019 AM EDT FRI JUN 11 2010 ...VALID 15Z FRI JUN 11 2010 - 12Z SAT JUN 12 2010... ...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL... SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM FNL VDW 30 SW BRX 35 WNW BRX 25 WSW SIB SIB 40 ENE SIB 35 WSW CDR 35 SSW CDR 15 NNW AIA 35 ENE AIA 20 NW TIF 30 WSW ONL 30 S YKN 25 WNW SUX 30 E SUX 25 SSW FOD IKV 15 ESE CNC 25 N CDJ 25 WSW CDJ 10 SW MCI 25 E MHK 30 NE SLN 30 N HYS 50 E GLD 35 NW ITR 30 NE LIC 30 ESE BKF BKF BJC FNL. SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM 35 S PAH 15 NE DYR 15 SSW HKA 30 SE M19 20 ENE SRC SRC 35 NNW LRF 35 ENE RUE 35 NNE RUE 25 SE HRO 10 N HRO 30 N HRO 30 ESE SGF 40 SSW TBN 20 ESE TBN 15 WNW FAM 20 NNE SAR ENL 15 E 1H2 35 E GEZ MGY 15 ESE HAO 40 WSW CVG 30 ESE HNB 35 S PAH. UPDATE... THE MCC THAT MOVED OUT OF THE CNTRL TO NRN PLAINS AND INTO THE UPR MS VALLEY OVERNIGHT/EARLY THIS MORNING CONTS TO SHOW SIGNS OF WEAKENING WITH WARMING OF CLOUD TOPS. THE PCPN REGION THAT REMAINS IS MOVG FAIRLY QUICKLY TO THE EAST NORTH EAST FROM ERN MN...NERN IA AND ACRS WI. GIVEN THE WEAKENING TREND AND THE PROGRESSIVE NATURE TO THE CONVECTION...THE EXCESSIVE RAINFALL POTENTIAL OUTLOOK AREA WAS REMOVED OVR THE UPR MS VALLEY TOWARD THE UPR LAKES REGION. SHRT TERM PCPN AMTS OF .50-1.5"+ POSSIBLE WITH THE CURRENT ACTIVITY...BUT WITH FFG RELATIVELY HIGH ACRS THESE REGIONS...DO NOT EXPECT WIDESPREAD RUNOFF ISSUES. THE FOCUS FOR ADDITIONAL CONVECTION LATE THIS AFTERNOON INTO TONIGHT AND EARLY SAT WL CONT FROM THE LEE OF THE CNTRL ROCKIES..EWD ACRS PORTIONS OF THE CNTRL PLAINS. A SFC FRONTAL BNDRY EXPECTED TO PERSIST INVOF SRN NE/NRN KS THIS PERIOD AND SHOULD ACT AS A FOCUS FOR ADDITIONAL ACTIVITY TO FORM ALONG AND NORTH OF IT AS THE LOW LEVEL INFLOW STRENGTHENS INTO THE BNDRY AFTER 0000 UTC. THIS AND FAVORABLE UPR DIFFLUENCE AHEAD OF SHRTWV ENERGY EJECTING NEWD ON THE ERN SIDE OF THE WRN U.S. TROF WL SUPPORT POTENTIAL FOR HEAVY TO POSSIBLY EXCESSIVE PCPN AMTS FROM FAR SERN WY/NERN CO...EWD ACRS LARGE PORTIONS OF NE...NRN KS AND INTO SWRN IA/NWRN MO. OVR THE OH VALLEY... CHANGES TO THE PREVIOUS OUTLOOK REGION WERE BASED MOSTLY ON LATEST RADAR TRENDS WITH THE SRN END OF THE PREV OUTLOOK DECREASED IN SIZE AND THE NORTHEASTERN PORTION EXTENDING SLIGHTLY FARTHER ENEWD. OTHERWISE...THINKING HAS NOT CHANGED FROM THE PREV DISCUSSION BELOW. ORAVEC PREVIOUS DISCUSSION... WEAK UPPER LVL DISTURBANCE..ACTING MORE LIKE A FORMER TROPICAL LOW..CONTINUES TO BE THE FOCUS FOR SGFNT CNVCTV RAINS..AND SHOULD REMAIN SO THRU THE PD. A STG AND MOIST SSWLY LLVL MSTR FETCH CONTINUES TO IMPINGE ON THE SLOWLY LIFTING OUT SYSTEM UNDER BROADLY DIV FLOW ALOFT ENHANCING SHWR DVLPMNT. WHILE THE GRADUAL ACCELERATION OF THE SYSTEM WILL EVENTUALLY LIMIT EXCESSIVE RNFL TOTALS..CANNOT RULE OUT THE POSSIBILITY THAT CELL INTERACTION AND SGFNT PW AVBLTY COULD RESULT IN SPOTTY EXCESSIVE RNFL TOTALS ALONG ITS TRACK. COULD SEE QUICK 2.00 INCH RNFL AMTS WITH ISOLD TOTALS IN THE 3.00 TO 5.00 INCH RANGE BEING POSSIBLE. WHILE ADMITTING THE LARGE OUTLOOKED AREA FM THE GREAT LAKES WSWWD TO E SLOPES OF THE CNTRL ROCKIES IS LIKELY OVERDONE..IT IS DIFFICULT TO PRECLUDE EXCESSIVE RNFL AMTS WITHIN THIS AREA GIVEN MODEL QPF GUIDANCE BEING ALL OVER THE PLACE. BASICALLY...SHRTWV ENERGY BEING EJECTED ACROSS THIS REGION FM THE WRN U.S. UPPER TROF WILL CONTINUE TO FIRE SHWRS WITHIN A BROAD BAROCLINIC ZONE LYING ACROSS THE AREA. IN ADDITION..PIECES OF SHRTWV ENERGY LIFTING NWD THRU THE PLAINS FM THE SUBTROPICAL STEAM WILL COMPLICATE MATTERS AND BELIEVE MODEL QPF GUIDANCE IS IGNORING THIS POSSIBILITY. IN ANY CASE...PWS IN PLACE AND A CONTG NWD MSTR FLUX TO ABET MSTR AVBLTY SHOULD SUPPORT HVY RNFL TOTALS WITH SFC WVS OVER THE UPPER MS VLY AND INVOF THE CNTRL HI PLAINS BY MID PD ENHANCING THE LLVL INFLOW IN THOSE AREAS. RT ENTRANCE REGION DYNAMICS WILL ENHANCE THE SYNOPTIC SCALE FORCING ACROSS THE UPPER MS VLY/GREAT LADES REGION SUPPORTING WHAT SHOULD BE A STRONG ISENTROPIC LIFT EVENT THERE. PLEASE SEE THE LATEST QPFPFD QUANTITATIVE PRECIPITATION FORECAST DISCUSSION TO BE ISSUED SHORTLY FOR A MORE DETAILED DISCUSSION OF THE SYNOPTIC SCALE SITUATION. KORTY $$