FXUS04 KWBC 210751 PAA QPFPFD QUANTITATIVE PRECIPITATION FORECAST DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 345 AM EDT WED JUL 21 2004 PRELIM DAY 1 AND DAY 2 QPF DISCUSSION VALID JUL 22/1200 UTC THRU JUL 23/1200 UTC REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR DAY1... UPR MS VALLEY/MID WEST/GTLKS... CONVECTION MAY BE FAIRLY ACTIVE ALONG THE SRN EDGE OF THE WLYS FROM THE UPR MS VALLEY...EWD INTO THE MID WEST AND GTLKS. THERE ARE A LOT SHRTWV DETAIL DIFFS BETWEEN THE ETA AND GFS. THE MAJORITY OF THE DIFFS RESULT FROM GRID SCALE CONVECTION PROBLEM THAT DEVELOP IN THE GFS FROM PRESENT UPSTREAM CONVECTION OVR THE CNTRL PLAINS. THE DAY 1 QPF...SUBSEQUENTLY...TRENDED MORE TOWARD THE ETA AND ETA SREF QPF...DEPICTING MDT TO HVY AMTS FROM ERN IA...EWD ACRS SRN WI...THE L.P. OF MI...NRN IL...NRN IN AND INTO WRN OH. MAX PCPN DEPICTED OVR NRN IL..EWD INTO NRN/CNTRL IN...SRN L.P. OF MI AND WRN OH WHERE VERY MOIST (PW'S 2"+) LOW LEVEL WLY FLOW MAY SUPPORT SOME TRAINING OF CELLS AT CONVECTIVE MAX TIME 0000-1200 UTC. SRN HIGH PLAINS.... THERE APPEARS TO BE ANOTHER MCV THAT HAS FORMED WITH THE PRESENT MCC OVR THE SRN HIGH PLAINS THIS MORNING. THIS MCV IS EXPECTED TO SINK SWD ON THE ERN SIDE OF THE MONSOON UPR HIGH OVR NRN MEXICO/AZ/NM BORDER. THE GFS APPEARS TO ALREADY BE VERIFYING BETTER WITH RESPECT TO THE MOVEMENT AND DEPICTION OF THIS MCV. CONVECTION MAY RE-FIRE AHEAD OF THIS MCV LATE THIS AFTERNOON INTO WED NIGHT/EARLY THU MORNING OVR SW TX AS THIS MCV DROPS SWD. MOIST SELY INFLOW EXPECTED TO CONT AHEAD OF THIS MCV WHICH SHOULD HELP SUPPORT ADDITIONAL CONVECTIVE ACTIVITY. WHILE THE SELY LOW LEVEL INFLOW SHOULD SUPPORT OVERALL PROGRESSION OF THE PCPN AREA TO THE SOUTH...LOCALIZED SHRT TERM RAINFALL AMTS OF 1-2" ARE POSSIBLE. NAME AREA... THE ETA AND GFS BOTH ARE SHOWING AN ACTIVE CONVECTIVE PATTERN ON THE SRN END OF THE MONSOON UPR RIDGE OVR NRN MEXICO/SWRN U.S. THIS IS IN A REGION OF MAX UPR DIFFLUENCE TO THE SOUTH OF THE MONSOON UPR RIDGE AND AN UPR TROF MOVG WWD FROM COASTAL S TX INTO NERN MEXICO. THIS SHOULD SUPPORT ANOTHER MCC OVR THE SRN PORTIONS OF THE NAME AREA (SRN ZONE 7 AND THE BORDER AREAS OF ZONES 7,8,9). THE GFS IS CONSIDERABLY HEAVIER THAN THE ETA...DEPICTING 5"+ AMTS VS .50-.75" AMTS. LOW CONFIDENCE IN THE GFS BULLSEYE VALUES...BUT BELIEVE WITH POTENTIAL FOR A MCC...HEAVY AMTS IN THE 1-2" RANGE ARE DAY 2... OH VLY/NORTHEAST/MID-ATLANTIC... XPCT A S/WV AND ASSOC VORT ENERGY CURRENTLY OVR THE NRN PLAINS STATES TO DROP ESE ACRS THE OH VLY EARLY IN THE PD AND BE ALONG THE MID-ATL SEABOARD LATE. SHD SEE AN ACTIVE AREA OF CONVECTION BREAK OUT IN ASSOC WITH DEEP LYR FORCING AND HIGH PWS OF LOCALLY 2 INCHES OR GREATER ALONG AND AHEAD OF AN APPROACHING CDFNT. THE MDLS HOWEVER ARE IN RATHER PATHETIC AGREEMENT REGARDING THE DETAILS OF HOW THE VORT ENERGY CROSSES THE APPALACHIANS. PART OF THIS IS RELATED TO THE EVOLUTION OF AN UPR LOW JUST OFF THE MID-ATL COAST. THE OH VLY WL LIKELY SEE A FAIRLY ORGANIZED BAND OF CONVECTION WITH HIGH INSTABILITY AND THE ETA AND GFS PROGGING RATHER STG H7/H5 IN ASSOC WITH THE VORT. THEREAFTER MORE SIGNIFICANT DIFFS ARE NOTED IN THE MID-ATLANTIC. THE GFS SENDS MUCH OF ITS BEST LIFT AND FORCING EWD ALONG A LINE FRM NY SWD TO VA WHILE THE ETA AND UKMET SHEAR OUT THE VORT ENERGY...TAKING SOME OF IT SEWD INTO THE S CNTRL APPALACHIANS AND TWD THE SRN MID-ATL WHERE AN UPR LOW WL BE APPROACHING FRM THE EAST. THE REST OF THE ENERGY WEAKENS OVR THE NRN MID-ATLANTIC. RIGHT NOW...FAVOR A COMPLICATED BLEND OF ALL THREE MDLS. INSTABILITY/MOISTURE SHD SUSTAIN DIURNAL CONVECTION PER THE ETA/UKMET INTO THE W SLOPES OF THE S CNTRL APPALACHIANS...BUT CONFLUENT FLOW AT H3 AND H8 DOWNSLOPING FLOW WL LIKELY SUPPRESS THE CONVECTIVE THREAT E OF THE MTNS ACRS THE NC/SC COASTAL PLAIN. FARTHER NORTH...FEEL THAT THE GFS WHILE OVERDONE WITH ITS QPF HAS A BETTER HANDLE ON THE MID/UPR LVL VORT ENERGY EXPECTED TO MOV EWD. LOSS OF DIURNAL HEATING SHD TEND TO WEAKEN THE CONVECTION BY LATE IN THE PD...BUT SOME ORGANIZED CONVECTION SHD MAKE IT E OF THE MTNS ACRS THE NRN/CNTRL MID-ATL GIVEN AND ESP WITH STG LOW LVL FORCING/HIGH THETA-E VALUES. PWS ARE PROGGED LOCALLY OVR 2 INCHES WHICH WL FOCUS HEAVY RAINFALL AMTS LOCALLY. THE ETA AND GFS BOTH SUPPORT A MAJOR CONVECTIVE FLARE-UP INVOF SERN VA/ERN NC AT THE END OF THE PD AND THAT SOLN IS DOWNPLAYED FOR NOW SINCE IT WL BE AT TIME OF DIURNAL MIN AND SFC BASED INSTABILITY WL NOT BE VRY IMPRESSIVE. WILL CONTINUE TO MONITOR THIS THREAT. FL PENINSULA... XPCT SOME INCREASE IN MOISTURE/INSTABILITY THIS PD ACRS THE PENINSULA. SHD SEE SOME WIDELY SCT DIURNALLY DRIVEN CONVECTION AS PROGGED BY ESP THE GFS. COASTAL TX/LA... DEEP LYR SRLY FLOW AROUND THE BACK SIDE OF UPR LOW MVG INTO MEXICO WL ENHANCE THE MOISTURE/INSTABILITY OVR THE REGION.SHD SEE SOME SCT CONVECTION WHICH WL BE DIURNALLY ENHANCED. MANUAL PROGS FAVOR THE SLIGHTLY WETTER/BROADER GFS COVERAGE. CNTRL PLAINS EWD INTO MIDWEST... ACTIVE CONVECTION IS LIKELY THIS PD ACRS A BROAD AREA FRM THE CNTRL HIGH PLAINS EWD INTO THE MIDWEST AS A CDFNT SINKS SLOWLY SEWD. S/WV ENERGY EJECTING OUT OF THE INTERMOUNTAIN WEST INVOF THE BNDRY AND IN CONJUNCTION WITH HIGH PWS WL SET THE STAGE FOR MCS DEVELOPMENT. XPCT VRY STG LOW LVL FORCING ALONG THE FRONT AND WITH GOOD UPR FORCING FRM H3 RRQ JET DYNAMICS. THE ETA AND GFS SUGGEST PWS AOA 1.75 INCHES ALONG THE FRONT FRM THE PLAINS EWD INTO THE MIDWEST WHICH WL PROMOTE HVY RAINFALL. THE MEAN FLOW WL BE NEARLY PARALLEL TO THE FRONT THIS PD AND THAT WL ALSO SUGGEST THE THREAT FOR TRAINING CONVECTION. WILL NEED TO MONITOR THAT THREAT. A BROAD AREA OF 1 TO 2 INCH RAINFALL AMTS AND LOCALLY HEAVIER ARE POSSIBLE. MANUAL PROGS FAVOR MAINLY THE ETA/UKMET SOLN OF PROPAGATING CONVECTION EWD ALONG THE BNDRY. THE GFS WHILE CONCENTRATED IS DISORGANIZED AND HAS TOO MUCH CONVECTIVE FEEDBACK IN IT. NAME/MEX... LOCALLY HVY RAINFALL/CONVECTION IS LIKELY AGAIN ACRS ESP CNTRL/SRN PORTIONS OF THE NAME AREA AS A CLOSED CYC ROLLS WWD THRU THE COUNTRY. SIGNIFICANT UPR LVL DIFFLUENCE IS NOTED OVR A BROAD AREA AND WITH DEEP LYR INSTABILITY/MOISTURE AND OROGRAPHICS ENHANCING THE CONVECTIVE THREAT. MANUAL PROGS FAVOR MORE OF AN ETA/UKMET SOLN WITH QPF. THE GFS APPEARS TREMENDOUSLY OVERDONE AND HAS CONVECTIVE FEEDBACK. STILL THERE SHD BE LOCALLY HVY RAINS WITH 2 TO 3 INCH AMTS POSSIBLE LOCALLY. FARTHER NORTH...MONSOONAL MOISTURE WL REMAIN TRAPPED UNDERNEATH THE SUBTROPICAL RIDGE AND WL PROMOTE ADDITIONAL DIURNALLY DRIVEN AND OROGRAPHICALLY ENHANCED CONVECTION. LOCALLY HVY RAINFALL AMTS ARE POSSIBLE ON AN ISOLATED BASIS HERE. ORAVEC/ORRISON GRAPHICS AVAILABLE ON THE WEB AT WWW.HPC.NCEP.NOAA.GOV 24HR QP VT 22/12Z 0.01 224063 229069 236074 240077 243085 251093 261102 265106 270109 275110 279109 284105 290103 299100 313097 318096 321094 324090 328089 342082 348080 353079 358079 365083 372086 379087 386085 390085 394086 400088 404087 407085 410083 412078 416076 418079 419084 421088 422095 423099 421103 419104 415107 412107 402106 397106 388107 378115 375118 376123 381128 385134 387143 390151 391154 395156 406144 418132 422127 430122 446117 449112 451107 452101 454094 454088 453082 450072 449064 447052 446037 443027 440018 429002 433982 435960 441946 444943 447942 456941 465940 474937 480931 504917 511893 512843 505800 482759 456772 406789 367816 364835 362851 364866 367881 378898 386918 383947 372977 365983 355992 347994 340998 330001 323004 316006 309007 300007 295007 292009 284011 278015 274021 270026 260033 253036 247034 240025 235019 235014 238008 243004 251997 244995 236993 233993 231997 0.01 310928 311922 310917 307906 304898 300891 294886 287882 284882 283885 282893 279910 277926 275942 274948 277953 281958 284960 288961 295957 301951 306946 309938 310930 310928 0.01 235808 238826 246837 252840 257840 262832 266820 270809 269799 264790 258788 251789 246791 240795 237798 235808 0.25 413972 419940 431930 439916 442895 451873 459857 465842 465822 458808 445805 412814 394818 386826 383839 384868 392894 396911 398929 397941 396949 394956 392961 387972 380984 373995 367004 360013 351021 351027 355029 359029 363028 366026 370024 380018 385014 391012 397008 401002 406991 410978 413972 0.25 226054 232063 240073 248083 256089 266096 271098 275098 280095 286093 291090 296085 299079 304065 308060 313055 321047 332039 337035 335028 326020 319017 314016 306017 298016 291018 285022 277031 273036 268039 263042 258046 253047 249047 244044 234037 228035 0.50 391866 404904 409918 416919 423916 429909 431895 430881 432872 440861 448847 444831 432824 419821 410822 402825 394831 391835 390839 390851 390859 391866 0.50 325032 324027 323025 318022 311021 303021 295022 288024 284028 282032 278038 274041 263046 261051 259054 257054 252053 245051 235046 230044 228045 227049 232059 239069 245077 253085 262091 268093 272093 277089 282087 287084 291078 293072 294067 296059 299053 302049 308046 318040 323035 325032 1.00 421863 421854 420851 417849 412842 408840 403840 399844 397848 398856 398860 401874 404885 406892 409899 412902 414901 418897 419891 421879 421867 421863 1.00 303036 304033 301031 298030 296031 293031 290031 287033 287034 285036 270050 270055 279056 287053 296046 297043 299041 300040 301038 303036 1.00 275078 274072 269066 266062 260060 253058 245057 241057 238060 241066 244071 248077 252080 257083 260085 264084 269082 275078 275078 1.50 416884 416877 414869 411864 409859 406853 403854 402858 402862 404865 403869 405877 406880 409887 411893 414892 415889 416884 1.50 258075 258073 258072 257069 256066 255066 253065 250065 248064 245066 246069 247071 248072 250074 253074 256075 258075 258075 24HR QP VT 23/12Z 0.01 224074 229080 235086 250099 266111 270114 274116 284114 289114 293116 301122 310126 316127 322126 326119 331115 333115 345133 351133 356131 358125 358119 351109 352103 355103 358103 363100 366097 370091 375102 382103 386100 390097 392101 391105 388110 382117 383121 387122 388120 393117 398118 404119 408118 412117 415111 419107 423106 427103 430103 431106 432112 434117 442128 447132 450133 454131 456126 458118 457099 455093 455082 452075 448069 445056 445047 445038 445031 444024 441012 433992 426978 423971 421966 421958 422952 424940 425922 421903 420899 420895 420890 421877 419872 417863 417861 418856 422850 430842 435838 442836 463829 469826 474823 479814 480809 482803 482796 480786 477778 474773 474770 476767 479764 487750 490744 492741 493736 493729 493724 491714 490707 491700 488691 485685 479681 475679 470680 462685 453693 444703 436709 429714 405726 393730 384732 373734 367736 360739 348745 343749 338753 335756 333762 330768 329774 327785 324788 319791 308797 305799 301798 297796 282791 267786 262784 257786 250791 245795 240799 237808 236811 238814 240821 243827 246830 254836 258838 263839 284837 302837 314848 316855 317861 317866 316870 311875 309879 307883 303886 292893 288895 285899 284923 282934 278944 271962 271971 274979 279988 287991 290990 293991 300990 303987 305981 306977 309972 314965 317960 318953 321943 324931 329921 337901 341898 345896 356894 361893 365896 369909 372922 373928 372936 372941 371948 369960 365971 362980 357990 350002 344010 339017 331025 322032 314035 309034 305031 298027 289028 283025 277023 271025 265023 262020 255015 240016 236017 230021 0.25 225063 231072 240082 249090 254095 260098 265100 272100 285097 293097 297097 304101 309104 314106 320104 328100 332099 336100 339099 340095 342088 346080 347070 355070 362070 369069 375073 387067 395065 400063 409063 417060 424056 427052 428039 427026 424010 418996 415986 414976 415956 417937 418928 416915 415901 414893 414883 410876 406871 400868 398866 397861 399852 404840 412827 431802 435794 438786 445772 453761 457754 462746 468739 471732 472725 472723 470720 468719 462718 456720 440726 433729 423732 410736 397741 390747 386749 382750 377751 371755 361761 353764 349768 345774 341782 342791 346798 350805 354813 355815 355818 353824 351831 352836 354840 359846 363850 373857 383862 387865 388868 390873 390876 388893 385910 382926 380940 376971 371986 364001 362007 360017 356032 353039 349044 344049 338052 332053 327055 328060 330066 329072 325077 320081 311078 302071 294068 286066 277059 271050 266047 261046 255044 247043 242042 237042 229044 0.25 300937 300930 296930 296935 295938 293944 291948 290952 288955 289958 292957 294954 297951 299947 300940 300937 0.50 454743 453737 450735 444734 432738 426738 418741 414742 411744 404749 383769 379776 376783 377787 380791 378798 371810 364820 361827 360831 362835 365839 370842 381847 384849 387848 393842 400830 408820 418808 421802 422796 423787 426780 431775 436769 441764 445757 450751 453744 454743 0.50 397781 396781 393782 390784 389785 391785 394784 396782 397781 0.50 411890 410884 407881 404880 399881 397883 394888 391896 388914 385932 382954 381964 379973 372990 370997 367008 367030 365038 361044 354050 352054 352058 355060 359060 365059 367057 383057 390056 401055 406055 409052 413044 419038 421035 421029 419019 416009 413997 411987 411975 412963 413943 414930 413920 411907 411894 411890 0.50 287087 285080 281075 272066 267062 261060 253052 247050 239049 232051 230057 232063 235069 242078 250088 255092 261095 266096 272094 277091 283089 287087 1.00 408891 406888 401887 396891 394896 392916 388939 385962 384974 383980 380984 377993 376999 379006 381006 385005 388001 392998 395997 399999 404996 406988 407972 408961 410938 409929 408922 407915 407907 408891 1.00 396042 396038 395035 395034 392031 392030 389029 386029