FXUS04 KWBC 282021 QPFPFD QUANTITATIVE PRECIPITATION FORECAST DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 420 PM EDT WED APR 28 2004 PRELIM DAY 1 AND DAY 2 QPF DISCUSSION VALID APR 30/0000 UTC THRU MAY 01/0000 UTC REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR DAY 1... NRN/CNTRL ROCKIES... MODELS REMAIN MOSTLY SIMILAR DIGGING CLOSED LOW AND EMBEDDED VORT ENERGY SLOWLY SWD THRU THE GREAT BASIN. JET ENERGY AND UPPER DIVERGENCE EAST OF THE SYSTEM CONCENTRATES ACROSS UT/WY AND PORTIONS OF CO DURING THIS PD. ETA AND GFS BOTH CONCENTRATE THE HVST QPF AMTS ALONG AN AXIS FROM THE UT WASATCH TO CNTRL WY. WITH LOW HEIGHTS SETTLING INTO THE GREAT BASIN PCPN COVERAGE SHOULD INCREASE DURING AFTN HEATING ON THU. PCPN EAST OF THE MTNS SHOULD BE ENHANCED FROM INCREASINGLY STRONG LOW LEVEL ELY UPSLOPE FLOW WHICH GENERATES HIGH UVV/RH VALUES OVER ERN WY. INDICATED SOME .50 INCH PLUS AMTS THRU THE FAVORED OROGRAPHIC AREAS OF UT AND WY WHICH IS GENERALLY SUPPORTED BY THE ETA/GFS. NRN PLAINS TO UPPER MS VALLEY... LARGE MODEL DIFFS ARE EVIDENT WITH 12Z GFS INDICATING SWATH OF .25 INCH QPF AMTS THROUGH SD/ND AND IN NRN MN WHILE THE ETA IS MOSTLY DRY. THE 12Z GFS VORT EJECTING FROM WY WHICH IS GENERATING THIS PCPN IS QUESTIONABLE AND LEANED TOWARD THE LIGHTER ETA. SOME LIGHT SHOWERS ARE POSSIBLE IN THE LOW LEVEL NRN PLAINS CONVERGENCE ZONE AS NRN STREAM VORT ENERGY BRUSHES ACROSS ND. A BETTER THREAT FOR RAIN SEEMS TO BE THU AFTN ALONG THE BNDRY ALIGNING DURING THU AFTN FROM IA TO SRN WI AND NRN IL AS SRN STREAM MOISTURE INFLOW AND POSSIBLE SHRTWV ENRGY REACHES NEWD. TX/SRN PLAINS... THE GFS HAS BEEN HANDLING THE PCPN BREAKING OUT OVER CNTRL TX BETTER THAN THE ETA AS SHRTWV SYSTEM ADVANCES ACROSS THE SRN PLAINS TONIGHT. MOISTURE AND LOW LEVEL FORCING ARE RATHER MINIMAL WHICH SHOULD KEEP PCPN MOSTLY LIGHT AND DISORGANIZED. SOME .25 INCH PLUS AMTS ARE POSSIBLE FROM NERN TX AND ERN OK....WITH REMNANTS OF THE UPPER SYSTEM AFFECTING MO ON THU. LOWER MS VALLEY...CNTRL GULF AREA... SCT CONVECTION SHOULD DEVELOP DURING THU AS GULF INFLOW INCREASES WITH PW VALUES SURGING TO ABOVE 1.5 INCHES IN SOME AREAS. MODELS SUGGEST THAT THE SRN PART OF THE TX UPPER SYSTEM SHOULD WORK INTO LA DURING THU...WHILE WEAK EMBEDDED GULF IMPULSE MAY LIFT NWD INTO MS/AL AND THE FL PANHANDLE. FL... AXIS OF HIGH PW VALUES LIFTS NORTH ALONG WITH INCREASING SELY FLOW. MOST FAVORED LOCATIONS FOR CONVECTION SHOULD BE THROUGH THE CNTRL AND WRN PART OF THE PENINSULA DURING DIURNAL HEATING. DAY 2... IN THE CENTRAL ROCKIES AND CENTRAL HIGH PLAINS...PCPN HERE WILL BE IN ASSOCIATION WITH INITIALLY CLOSED UPPER LOW SWINGING ACROSS THE AREA. THE GFS IS FASTER THAN THE ETA WITH THIS SYSTEM. THE UKMET AND THE CANADIAN MODELS SUPPORT THE FASTER GFS SOLUTION. THEREFORE HAVE LEANED TOWARDS THE HEAVIER GFS PCPN FORECAST. PCPN WILL BE IN THE FORM OF SNOW AT HIGHER ELEVATIONS. FROM THE CENTRAL PLAINS NEWD ACROSS THE MID MS VALLEY TO THE GREAT LAKES... PCPN... MDT TO HVY... WILL BE FALLING GENERALLY ALONG FRONTAL ZONE. THE GFS IS SLOWER THAN THE ETA WITH THE SHORT WAVE TROF SWINGING ACROSS CANADA... AND IS THEREFORE SLOWER WITH THE EWD PROGRESSION OF THE BAND OF FRONTAL PCPN. MOST OTHER MODELS ARE LEANING TOWARDS FASTER ETA SOLUTION. HOWEVER... THE GFS ENSEMBLE MEAN SUPPORTS THE GFS OPERATIONAL FORECAST. ALSO... THE ACCEPTANCE OF THE FASTER GFS MOVEMENT OF THE CLOSED LOW TO THE SOUTH IN THE CENTRAL ROCKIES SUPPORTS THE SLOWER MOVEMENT OF THE CANADIAN SHORT WAVE TROF. THEREFORE... BELIEVE A COMPROMISE IS IN ORDER... AND HAVE USED THAT IDEA IN MAKING THE PCPN FORECAST. IN THE NATIONS SOUTHEASTERN QUADRANT... BOTH THE ETA AND GFS MODELS ARE BRINGING SRN STREAM SHORT WAVE ENERGY NEWD THRU THE REGION. AS FAR AS PCPN IS CONCERNED... BELIEVE THE GFS IS BETTER IN BEING SLOWER TO TAKE BEST ZONE OF GULF MOISTURE INFLOW EWD. THEREFORE... FEEL GFS IDEA OF HOLDING BACK OR REDEVELOPING LIGHT TO MDT SHOWERS IN THE CENTRAL AND WRN GULF STATES MAKES SOME SENSE. AS FAR AS HVY CONVECTIVE RAINS DEVELOPING FROM ATLANTIC INFLOW... BELIEVE THE GFS IS OVERDONE IN NRN FL. HOWEVER... THE ETA IS PROBABLY TOO FAST TO DEVELOP HVY RAINS IN GA FROM THE SAME LOW LEVEL FLOW. HEDGE/LINDNER GRAPHICS AVAILABLE ON THE WEB AT WWW.HPC.NCEP.NOAA.GOV 24HR QP VT 30/00Z 0.01 503854 502842 499833 493821 486809 479800 470790 467785 469780 471773 473766 474754 474748 472743 465733 451723 448721 445721 440724 438728 431745 430753 431762 432768 435772 438776 437781 436785 436789 436795 437800 439804 441808 447818 448823 446830 441840 435849 429856 425861 421864 418868 414871 400882 382892 360903 355903 349902 341898 338894 336889 334875 330861 328854 325848 323843 319840 312836 303834 300833 294834 289837 287840 285849 283855 279860 275865 272870 271874 270881 270892 270903 272916 275927 280939 285947 290955 292958 289961 286962 281969 277977 271992 268999 267003 267008 272012 273015 273019 276023 280025 286027 293027 298024 304017 313010 326001 335994 338993 341989 355979 362974 370968 375963 383959 387961 388964 389974 391975 396972 404965 410962 413960 423952 430942 439925 445916 451912 453910 456911 457917 456920 455932 453944 450953 441971 435984 430993 427999 425006 421018 419023 415027 410027 406024 402022 396022 393026 391031 389035 386036 375036 370036 363043 358051 357054 358058 359061 359065 355066 349066 344068 346070 351074 353077 355083 356090 353095 346102 340107 341111 344115 351123 358129 365128 370128 373132 376133 378139 381143 385146 389149 391145 391142 390135 393131 397129 402131 405132 408131 410129 413129 413135 413141 409147 403155 403159 408160 417163 421159 424155 426152 427147 427139 431132 434128 438127 442136 445137 448133 451130 460127 466119 470110 472104 473096 470091 467090 464093 461093 462086 463078 463068 462062 462052 463037 464024 466010 468995 470986 472981 475972 480962 490941 499921 501913 501909 502898 503884 503870 503854 0.01 293811 290806 286804 278798 274794 270792 259794 250801 248806 248809 250812 253816 256819 265825 273828 284828 289826 292821 293815 293811 0.25 435886 432885 428887 423891 419900 416905 415913 413921 413926 417927 421919 424914 428907 432900 435890 435886 0.25 449076 449070 447066 445058 446039 444035 441034 436037 432040 426043 414046 404053 396058 393062 392064 392070 396070 398065 401067 401070 401075 403079 402090 401100 399105 394109 385116 384118 385122 387123 394121 399121 406121 414121 420119 424116 423112 421111 429109 434105 438104 441100 444097 444093 442087 441082 444079 449076 0.25 427100 427099 424096 424095 422095 422099 424102 426102 427100 0.25 400932 397930 394931 391933 389935 388935 387939 389940 392941 395941 398938 399936 400933 400932 0.25 395079 395076 392073 390076 389077 389079 389080 392081 395079 0.25 373942 371941 367941 363944 353952 346960 338967 330975 326981 327985 329985 333983 337980 342976 346972 352964 360955 370947 373942 0.25 379079 379075 378072 377072 375070 375072 375075 375076 377079 378080 379079 0.25 334912 327911 320910 315911 307912 304914 299916 294922 293932 295936 298938 304943 310944 314941 315936 315930 319923 328918 332916 334912 0.25 324881 321872 317863 311854 304848 301847 297849 295854 296860 298869 301878 305888 310895 315897 319898 322895 323891 324884 324881 0.25 280819 278814 276811 274806 270801 266799 263799 258801 255804 254807 256811 260815 263816 266818 270820 274821 276821 280819 0.25 303001 304998 302995 301995 299995 296995 293997 292999 291001 290002 290006 290009 292010 294011 297010 298008 300006 301004 302002 303001 0.50 436068 436063 433056 430054 424054 422057 423060 421068 423072 423076 421084 422088 424090 427092 430095 432092 430085 428080 427076 430073 434072 436068 0.50 410110 410106 410103 410099 409098 406098 406099 406102 405106 405110 404114 406114 408114 409114 410110 0.50 317880 317876 316873 315870 314867 312864 311863 310862 308859 307858 304859 304860 304864 305867 306870 307873 308874 309875 310878 312881 313882 316883 317880 0.50 270804 268803 265803 265802 262803 261804 261807 261810 261811 262811 265813 268812 268811 269808 269807 270804 24HR QP VT 01/00Z 0.01 499668 497659 494657 486658 480663 477667 472679 467691 464702 458722 452747 449760 444773 440786 435798 430809 425820 418840 414850 410860 405870 400879 391896 385909 382913 377918 374920 369921 363922 359923 357921 361913 366904 370895 377886 382879 386871 402857 405853 408848 412839 416829 419819 422809 426796 429784 431774 436745 433743 429746 419756 405772 391788 377802 373807 369810 360817 352821 345822 335821 326816 324812 323807 322799 320793 317789 308784 301780 296780 292781 282784 272789 263794 255800 249805 247809 247813 249816 254818 260821 277830 279832 279836 279839 278850 278863 279875 280887 280895 282903 284907 287910 290912 292915 294939 294951 292958 290963 287966 279970 269974 269980 272984 278990 286996 290997 297996 307993 315985 321976 330962 341946 346939 350932 352928 354931 353943 354953 357959 360966 361977 362993 361006 357030 353042 351046 350054 353065 355075 355082 355086 358089 361091 362097 364100 368100 377101 388104 389107 388110 382117 379120 377124 378127 382131 386134 390135 394131 405127 410122 412116 418084 418080 421075 428069 430064 431055 431051 429049 427045 426031 427018 427003 425989 424981 425973 432961 437951 440945 442938 450910 454900 461890 468883 474875 480864 485854 489845 492832 499808 503794 508777 510762 511746 511732 511718 509701 507690 504686 501683 497682 497679 499668 0.01 544860 543854 540853 531857 522864 515869 510876 505883 500892 496900 488916 484924 480934 479939 479946 484949 485955 483960 481971 480981 481985 485986 486009 487019 486028 486035 488041 489047 491051 495054 497054 502053 511049 518044 523039 526029 526012 525996 524989 524981 526971 528958 529946 528940 526937 524931 524923 522914 527905 532897 535890 539879 542869 544860 0.25 485711 483705 480709 477717 471735 467744 463755 457777 451793 445809 437827 428845 421860 414875 410883 405892 396907 387921 380933 376943 373952 372963 371975 372986 374998 375009 374019 371028 367039 362047 361050 360054 362062 364066 366069 378077 398073 404070 410064 413057 409050 409041 412031 414019 414009 412003 413998 414987 414978 417968 419961 423953 427944 431933 435924 439917 451884 468844 470837 472825 476808 480784 483773 486764 487758 486750 484742 484737 485721 485711 0.25 515011 515007 515002 514997 512996 511998 509000 508003 507005 505008 504011 504013 503017 505020 507019 510017 511017 513015 515011 0.25 401835 400831 397828 392827 388827 381828 375832 370836 359845 354848 347850 334854 323853 318851 313848 306841 303837 307834 313830 316825 318821 318814 317807 315799 312794 308791 303790 296789 284792 279794 273799 273802 275809 278814 282818 286823 290827 292832 290836 288841 287847 287853 287860 288868 289875 292889 299897 302903 304912 304921 304926 304933 306939 309942 314941 322932 329922 335914 341907 347902 352899 357894 360888 371870 375865 379861 384857 391851 396844 399839 401835 0.50 475752 472751 469754 468759 466763 464768 462774 460780 458785 457790 458792 460789 463786 465781 468775 470769 472763 473758 475752 0.50 463819 461809 459805 456807 449817 441830 434843 428855 424866 421872 419881 416888 412894 383936 379946 376958 376976 378982 379992 380000 382008 383014 383022 375035 369046 367052 367056 369059 373062 380063 395061 400057 403049 406034 406029 406021 397011 395009 395003 398997 401994 404989 407984 409977 409967 411958 416945 425922 433911 437905 441897 445885 450873 456859 461843 463831 463819 0.50 377848 375845 373846 366848 358852 353855 348859 343862 329864 318862 309854 305850 301848 298848 296851 293853 293857 293870 295879 299888 307895 311901 309909 308915 308922 309926 312925 315920 321911 331900 338893 342887 348884 354880 358877 363872 366863 371855 377848 0.50 313806 311802 308800 300798 292796 289795 283797 281799 280806 283812 290818 296823 302828 304827 309822 313816 313806 1.00 442876 442871 442867 439867 437869 436869 434873 434874 432878 432879 430883 430884 429888 429891 429892 429893 432893 435891 435890 437888 438885 439883 441880 441877 442876 1.00 405942 406938 404935 403935 401938 400940 398943 398944 396947 395948 394951 393953 391956 391957 392957 394957 397956 400955 402951 402950 405946 405942 1.00 398034 396031 392030 388031 383035 381039 378043 376047 376050 378054 381054 384053 389050 392048 395045 397038 398034 1.00 309811 308809 307808 305806 304805 301804 300803 297802 294802 291804 290805 289807 289809 291811 291812 294814 295815 296816 299818 302819 305819 307816 307815 309812 309811 1.50 303813 302811 302810 299810 296811 296813 297813 300815 301815 303814 303813 $$