FXUS04 KWBC 241930 QPFPFD QUANTITATIVE PRECIPITATION FORECAST DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 328 PM EDT SAT APR 24 2004 PRELIM DAY 1 AND DAY 2 QPF DISCUSSION VALID APR 26/0000 UTC THRU APR 27/0000 UTC REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR DAY 1... THE CONTINUES TO BE POTENTIAL FOR WIDESPREAD HVY PCPN MOVG ENEWD FROM THE SRN PLAINS INTO THE LOWER MS VALLEY...LOWER OH VALLEY AND MID WEST AHEAD OF THE MEAN TROF THAT IS EXPECTED TO REMAIN OVR THE MID SECTION OF THE NATION. WHILE THE STRONG CLOSED LOW OVR THE CNTRL HIGH PLAINS WL CONT TO WEAKEN AS IT PUSHES NEWD DAY 1...THE OVERALL MEAN TROF DOES NOT MOVE AS QUICKLY OR WEAKEN...THUS CONTINUING HEAVY PCPN THREAT TO ITS EAST. THE AMT OF PCPN FOR THIS UPCOMING DAY...HOWEVER...WL LIKELY NOT BE AS HEAVY OR AS WIDESPREAD WITH VERY HEAVY AMTS AS WHAT OCCURRED OVR THE PAST 24 HRS GIVEN WEAKER LOW TO MID LEVEL DYNAMICS COMPARED TO THE PAST 24 HRS. STILL...WITH ABUNDANT MOISTURE AND STILL FAVORABLE JET DYNAMICS ALONG THE FRONTAL BNDRY EXPECTED TO STRETCH FROM CNTRL TO ERN TX...NEWD INTO THE LOWER MS VALLEY/LOWER OH VALLEY AND INTO THE MID WEST...HVY PCPN AMTS ARE LIKELY. THERE ARE THE USUAL DETAIL DIFFS WITH THE QPF BETWEEN THE OPERATIONAL ETA/GFS AND THEIR CORRESPONDING SREF MEMBERS. MAKING THINGS WORSE...IS THE UNCERTAINTY IF THE MODELS ARE HANDLING THE CONVECTIVE VORT OVR NERN TX CORRECTLY. BOTH MODELS SUGGEST THIS VORT BREAKING INTO TWO PIECES...ONE MOVG NEWD IN THE MEAN SWLY FLOW INTO THE MS VALLEY/LOWER OH VALLEY AND MID WEST...WHILE ANOTHER PIECE PUSHES MORE EWD INTO THE GULF COAST. BOTH MODELS INITIALLY APPEAR UNDERDONE WITH THE WELL DEFINED INFLOW BAND OF PCPN AHEAD OF THIS VORT OVR LA..WRN MS AND ERN AR. DAY 1 PROG INCREASED PCPN IN THIS INFLOW AREA DURG THE FIRST 12 HRS WHEN EXTRAPOLATION OF IT MAY WORK BETTER. MODELS WERE MORE SIMILAR FARTHER TO THE NORTHEAST ALONG THE FRONT INTO THE LOWER OH VALLEY AND INTO THE MID WEST WITH .50-1"+ AMTS DEPICTED. ACRS ERN TX INTO LA AND NRN TO WRN MS...THERE ARE LARGER MODEL DIFF THAT DEVELOP TONIGHT AND CONT INTO TOMORROW WITH RESPECT TO HOW MUCH ADDITIONAL CONVECTION FIRES AHEAD OF THE MAIN FRONTAL BNDRY. WITH ABUNDANT MOISTURE EXPECTED TO REMAIN ACRS THIS AREA IN THE WAKE OF THIS MORNING CONVECTIVE COMPLEX..CONT FAVORABLE UPR DYNAMICS IN THE RT ENTRANCE REGION OF THE UPR JET AND CONVERGENCE FROM THE MAIN FRONTAL ZONE...BELIEVE THE HEAVIER GFS DEPICTION IS BEST. THE GFS IS...HOWEVER...SUFFERING FROM APPARENT GRID SCALE PROBLEMS ACRS THIS REGION...BUT ITS OVERALL IDEA OF HEAVIER QPF THAN THE ETA LOOKS GOOD. SEVERAL OF THE ETA...ETAKF AND RSM SREF MEMBERS...ALONG WITH THE CAN GEM SUPPORT HEAVIER PCPN AMTS. THE DAY 1 PROG LEANED TOWARD THE GFS...ALBEIT SLIGHTLY TONED DOWN FROM THE GFS' BULLS EYE MAXES. 1-2"+ AREAL AVG AMTS DEPICTED DAY 1 ACRS ERN TX INTO LA...NRN TO CNTRL MS DAY 2... ...18Z UPDATE... ...ATLANTIC COAST STATES.... MODEL QPFS ARE IN PRETTY GOOD AGREEMENT CONCERNING THE PRECIPITATION ALONG THE COLD FRONT PASSING THRU THE E COAST STATES DAY 2...AND HAVE GOOD CONTINUITY FROM THE PREVIOUS PACKAGE. IN GENERAL...WE BLENDED THE ETA AND GFS QPFS BUT BEEFED UP AMOUNTS A BIT OVER MS/AL FOR SUN EVE WHERE THE HIGHEST PWS ARE EXPECTED AT THE TIME OF FROPA. WE PREFERRED THE ETA QPF OVER WV FOR SUN NIGHT AS THE GFS MAXIMUM OF 2.00 PLUS LOOKS A BIT GENEROUS. THE LIFTED INDEX FIELDS OF THE ETA AND ESPECIALLY THE GFS SUGGEST ONLY MARGINAL TO WEAK INSTABILITY AS THE FRONT CROSSES THE APPALACHIANS SUN NIGHT. AS THE COLD FRONT REACHES THE PIEDMONT AREA MON AM...WE PLAYED UP A DIURNAL MINIMUM OF FRONTAL ACTIVITY THRU CENTRAL PORTIONS OF GA/THE CAROLINAS/VA. HOWEVER...FRONTAL ACTIVITY SHOULD RE- INTENSIFY LATER MON AFTERNOON CLOSER TO THE COAST FROM SERN VA SW THRU THE CAROLINAS INTO GA. ....RIO GRANDE AREA... WE PLAYED UP THE IDEA THAT DRIER AIR FROM THE NE WOULD SWEEP THE DEEPER MOISTURE AND INSTABILITY OUT OF TX TOWARDS THE RIO GRANDE VALLEY. WE SHARPLY DECREASED THE ETA EXTENSION OF THIS RIO GRANDE PCPN INTO W TX AS EXCESSIVE.PCPN THERE HAS SOME UPPER SUPPORT FROM AN UPPER SHEAR AXIS DRIFTING SLOWLY S THRU TX MON...BUT THE ETA AREAL COVERAGE EXCEEDING .25 LOOKED OVERDONE. ORAVEC/FLOOD GRAPHICS AVAILABLE ON THE WEB AT WWW.HPC.NCEP.NOAA.GOV 24HR QP VT 26/00Z 0.01 385917 390916 398916 403920 407935 403947 402965 407974 420983 448999 475001 508952 517888 507828 486755 475738 466729 457722 435719 431721 429724 424732 416744 404769 399780 391792 385797 381799 377799 369792 359785 354781 349779 338773 334770 327775 331787 331792 330795 328801 327806 326810 328814 332823 336828 343840 344849 339857 328865 295880 275890 270903 267920 265933 259954 254972 250993 252011 265021 280024 291023 302014 319992 345949 352939 359931 366926 372922 379918 383916 385917 0.01 431076 432068 431060 430055 427048 421041 415035 409034 403035 398037 395040 390050 393061 393068 392072 394075 398079 401081 407083 410083 412086 415087 421087 427084 429080 431076 0.25 362919 382909 400905 412908 424917 431928 433941 441956 453955 465945 476933 486919 491903 490882 486860 478853 469849 458829 457809 459791 454765 440758 429762 417774 397805 392812 385821 379829 372837 366843 359850 354857 346863 338868 330874 313886 304889 293891 288893 283895 281898 281904 284909 285913 286921 285933 281943 278950 274956 264969 262980 261990 262996 264999 272003 279006 285006 290004 298999 303994 309987 312985 317983 320980 323977 328968 329965 331959 331954 332950 337943 343935 355923 362919 0.50 366909 391896 400892 416879 435852 446821 450798 451780 447770 436770 425775 415785 403810 391828 387826 379838 367852 363857 358862 345870 330879 319887 307894 301894 296896 291899 291902 290908 291912 292918 292923 290929 286940 280952 273965 268977 266983 267992 271998 275001 280004 286000 296992 302988 306983 313973 318966 321960 323954 327946 334936 338931 344927 357917 366909 1.00 439791 440787 438785 435785 434786 432787 430791 429793 431793 432795 435797 437795 439792 439791 1.00 380894 419851 438818 440799 440790 432790 426807 415835 406849 392858 372869 352878 327889 322892 314899 306907 301917 292936 288947 284959 283963 284971 290979 296981 300979 307969 313961 319952 321946 323939 327931 347917 355910 361905 366903 375896 380894 1.50 309955 329923 359901 379886 388880 389873 380876 366883 355888 344890 335892 326896 318903 308912 302924 297934 293945 292953 292958 296961 303960 309955 2.00 315912 304930 303937 304943 311937 324921 331916 336913 340906 339901 334901 326905 318910 315912 24HR QP VT 27/00Z 0.01 534723 528708 515691 497688 488679 480661 470645 462629 450622 441625 433632 421649 419655 407672 399685 390700 379716 373726 369734 358751 336780 328792 318804 305819 293832 284844 281848 279850 275857 270864 266871 264880 265887 266891 269892 274893 280893 281901 274914 270923 257942 244957 240974 242996 243000 245009 246013 249018 252023 257031 260038 265057 267067 273076 289074 334999 338987 336984 332984 329988 325996 320002 301021 297014 291007 287000 283994 281990 279983 280972 281963 286956 292942 296934 300930 311918 321908 325902 331897 342886 371858 385842 397832 404824 408829 410833 408852 415856 424854 430857 434868 449888 463897 477897 487891 518870 523866 526861 530849 535839 539828 541825 543819 544812 545805 547789 546773 534723 0.01 526918 525912 521905 518903 512904 506907 501911 492915 487918 484922 479927 479932 480936 484941 488943 493943 504939 513935 521928 524924 526918 0.01 299822 297816 294814 291812 287810 284808 280806 274806 272807 271810 272816 275821 278824 282825 286826 290825 295825 299822 0.25 527761 523733 511718 506715 501714 496717 491723 487723 477713 468691 459668 450655 440656 432662 422678 412701 409708 407716 403729 399744 394758 383782 377790 373796 365804 355806 347810 334826 324837 319836 323829 325826 328820 336810 346802 358789 363783 367777 384752 389741 394727 395723 395720 394718 391717 386719 378732 369745 360757 351769 344779 331799 325807 320812 311823 294843 285853 279862 276867 274874 275877 280878 286874 291871 296869 293884 289897 285911 284917 283920 284925 287923 291919 299911 307902 318894 329884 349865 390828 401817 407811 412807 416805 430796 436793 442791 449792 452796 454801 458808 461817 463827 466834 470842 475846 481845 485842 491837 499831 507824 512819 518810 522803 525795 527786 528775 527761 0.25 287018 285013 282006 276995 273987 271980 271972 270967 263958 256957 248965 246978 246989 249004 255009 265014 273020 278023 283023 286022 287018 0.25 281042 275039 271045 275055 282059 285058 285053 284050 283047 282045 281044 281042 0.50 464720 454691 444675 437675 425686 418701 414710 412717 408733 406740 406747 403756 400761 393773 389780 385787 376798 360816 352827 339843 324858 304877 301881 298888 293898 291904 293910 297907 307897 314890 319886 339866 350858 360848 380828 391819 401809 412797 418791 420785 423778 428772 431770 439769 446768 454764 458761 461757 464750 465740 465730 464720 0.50 378747 373748 368753 361760 356767 351775 345784 340790 338794 342794 349788 355780 361772 366766 372757 375753 378747 0.50 321823 322819 320820 318822 311829 305837 300842 293850 288856 285860 284864 288865 293862 299855 305850 311841 315834 319827 321823 0.50 279010 274001 271992 268983 266974 263969 261966 257965 254967 252970 251979 251990 253999 260005 264007 272010 275011 278012 279010 1.00 445712 442707 437705 433707 429710 426713 424715 422719 421724 422728 425728 431726 434725 439722 442719 445712 1.00 407775 403774 398779 391786 384794 379802 374810 372813 368818 367822 367826 370827 377822 387814 394806 400799 403795 405790 407780 407775 1.00 264996 265993 264990 264987 263984 262982 261981 259978 256982 256985 256988 256991 257993 258994 260995 262996 263997 264996 $$