589 FOUS30 KWBC 031410 QPFERD EXCESSIVE RAINFALL DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 1010 AM EDT FRI JUL 03 2009 ...VALID 15Z FRI JUL 03 2009 - 12Z SAT JUL 04 2009... ...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL... SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM 35 SSE RAP 15 ESE PHP 35 ENE PIR 30 ESE HON 20 W OTG SLB IKV 15 WSW OTM 35 SSE CNC 30 WSW LWD 20 NE BIE 10 NW JYR 10 W BVN 35 SW ONL ANW 35 SE IEN 10 WSW IEN 35 SSE RAP. ...CENTRAL PLAINS... THREAT OF HEAVY TO PSBL EXCESSIVE RAINS WILL EXIST FROM PORTIONS OF SD/NE SEWD INTO IA... AS S/WV ENERGY LIFTS EWD... OUT OF THE WEST.. OVER A FLATTENING UPR RIDGE INTO THE NCNTL PLAINS THEN SLIDES ESEWD TOWARD THE MID MS VLY BY SAT MORNING. THE UPPER DYNAMICS WILL HELP IGNITE CYCLOGENESIS ALONG A WAVY E/W FRONT... WHICH WILL MAINLY BECOME WARM... THRU THE PLAINS. THE SURFACE LOW WILL TRACK GENLY EWD TOWARD THE MID MS VALLEY. A STRENGTHENING LOW LEVEL JET OF 40 KTS OR SO AHEAD OF THE WAVE WILL HELP SUPPORT STG MSTR FLUX N OF THE WARM FRONT WITH MODEST UPPER EXHAUST FROM RT ENTRANCE REGION OF UPR JET..ALL OF WHICH SHOULD SUPPORT A BAND OF MDT TO HEAVY CONVECTIVE RAINS FROM PORTIONS OF SRN SD/NRN NEB SEWD INTO IA/NRN MO THIS PD. IMPRESSIVE MSTR WILL BE AVAILABLE FROM THE GULF BUT ALSO FROM THE SW OR MONSOONAL RELATED..NEAR 2.00 INCH PWS..WHICH SHOULD SUPPORT A STRIPE OF 1 TO 2 INCH PLUS RAINS WITH ISOLD AMOUNTS NEAR 4 INCHES CLOSE TO THE EXPECTED 85H LOW TRACK..WHERE STGEST LOW LEVEL SPEED/DIRECTIONAL CONVERGENCE IS FCST. THE ONLY QUESTION MARK IS WITH THE MODEL GUIDANCE... SOME SPREAD EXISTS ON POSSIBLY FOCUSING THE FORCING/HEAVY RAINFALL AXIS TOO FAR NORTH INTO THE MODEST COLD SECTOR THAN NEAR THE BEST CONVERGENCE AND THE MODELS PERFORMED QUITE POORLY SEVERAL WEEKS AGO WITH PIECES OF ENERGY EJECTING OUT OF THE WEST INTO THE PLAINS. NEEDLESS TO SAY... WITH NO NEW GUIDANCE... HPC WILL STICK WITH EARLIER THINKING AND KEEP A SLIGHT THREAT IN PLACE. ...AZ/NM... THE THREAT FOR SLOW MOVING CONVECTION AND HEAVY RAINFALL WILL CONTINUE TODAY ACROSS PORTIONS OF AZ AND NM. AN UPPER RIDGE... EAST OF THE REGION... WILL KEEP FUNNELING NORTH DEEP MONSOONAL MOISTURE INTO SW AS NUMBERS THIS MORNING ARE EASILY AOA 1.5 TO 1.75 INCHES. THE COMBINATION OF THIS DEEP MOISTURE PLUME... A STALLED MID-LEVEL CIRCULATION OVER ERN NM AND ADDITIONAL SHEARING UPPER DYNAMICS ARRIVING FROM BAJA SHOULD YIELD ISOLATED TO SCATTERED CONVECTION. THE OVERALL STEERING CURRENT FROM 850 TO 750 MB IS 5 KTS OR LESS WHICH MEANS THE DEVELOPING ACTIVITY SHOULD MOVE VERY SLOWLY NORTH AND EAST AROUND THE WRN EDGE OF THE 500 MB RIDGE AXIS. ADD THE FACT MOISTURE/RAINFALL OVERNIGHT REMAINS RATHER PREVALENT THIS MORNING... IT WILL NOT TAKE MUCH FOR THIS AFTNS ACTIVITY TO IMPACT AREAS WITH HEAVY TORRENTIAL DOWNPOURS AND RUNOFF ISSUES. MUSHER $$