FXUS04 KWBC 142203 QPFPFD QUANTITATIVE PRECIPITATION FORECAST DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 502 PM EST TUE JAN 14 2003 FINAL DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION VALID JAN 16/0000 UTC THRU JAN 18/0000 UTC REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR ...18Z UPDATE..ETA AND GFS DID NOT SHOW ANY SGFNT CHGS TO THEIR PREVIOUS FCSTS..SO NO CHGS WERE MADE TO THE PRELIM DAY 1 QPF... DAY 1... .....NORTHERN ROCKIES AND PLAINS......... THE MODELS ARE IN PRETTY GOOD AGREEMENT THAT THE SHORTWAVE NOW JUST ENTERING THE PAC NW WILL DIG ACROSS THE NRN ROCKIES AS UPPER LEVEL RIDGE BUILDS TO THE WEST. THE SHORT WAVE SHOULD PRODUCE PCPN ACROSS THE MTNS OF ID....WRN MT AND NWRN WY DURING THIS FCST PD WHERE THE QPF IN BOTH THE GFS AND ETA ARE PRETTY GOOD AGREEMENT NOW THAT THE ETA HAS TRENDED WETTER THAN ITS PREVIOUS RUN. EACH MODEL ALSO DEVELOPS A SFC LOW TO THE LEE OF THE ROCKIES IN NRN WY AND THEN LET IT SHIFT SSEWD RAPIDLY DURING THE NEXT 24 HRS. ALL THREE SHORT RANGE MODELS PREDICT A STRIPE OF MDT TO HVY SNOWFALL IN THE ZONE OF ISENTROPIC LIFT TO THE NORTH OF THE SYSTEM. THE GFS PREDICTS SOME LIGHT PCPN S OF THE LOW. THIS PCPN LOOKS TOO WIDESPREAD. ...GREAT LAKES REGION INTO THE MID ATLANTIC STATES....... BOTH THE GFS AND ETA INDICATE THAT AT LEAST TWO SHORT WAVES WILL BE SHIFTING EWD FM THE OH VALLEY REGION ACROSS THE CENTRAL APPALACHIANS TO THE MID ATLANTIC STATES. RADAR AND SATELLITE IMAGERY INDICATE THERE MAY BE MORE THAN ONE IMPULSE BUT SUGGEST THAT EACH WILL BRING AN AREA OF HIGHER RH WITH IT. THE SECOND VORT HAS STRONG PVA ASSOCIATED WITH IT SUGGESTING IT WILL PRODUCE SNOW SHOWERS ACROSS THE REGION. THE ETA AND GFS ARE IN EXCELLENT AGREEMENT IN BRINGING A FEW OF THESE SHOWERS EWD ACROSS THE MTNS INTO VA AND MD. DAY 2... THE HEAVIEST PCPN THIS PERIOD WILL BE FOUND OVER THE MO AND MID- MS VALLEYS IN ASSOCIATION WITH THE PASSAGE OF A SHORTWAVE TROF. WHILE THE ETA AND GFS DIFFER SLIGHTLY WITH THE INTENSITY AND TIMING OF ITS PASSAGE...THEY ARE ACTUALLY NOT TOO TERRIBLY DIFFERENT WITH THEIR RESPECTIVE QPFS. EXPECT A BAND OF SNOW TO EXTEND FROM ERN NE/KS AND SRN IA ACROSS MOST OF MO INTO WRN IL. QPF APPROACHING .50 INCH IN PLACES SUPPORTS GENERALLY 2-4 INCH SNOWFALL AMTS. AHEAD OF THE DEVELOPING WEAK LOW PRESSURE IN THE SOUTHEAST...WEAK FRONTAL BNDRY WILL SUPPORT LIGHT RAIN SHOWERS FROM ERN TX INTO THE LOWER MS VALLEY. FARTHER NORTH... EXPECT SOME LIGHT LAKE EFFECT SNOW TO CONTINUE AS NRN STREAM ENERGY DIVES SEWD FROM CNTRL CANADA INTO THE UPPER MIDWEST. DAY 3... STILL SOME QUESTION AS TO HOW MUCH OF AN EFFECT THE NRN STREAM WILL HAVE ON THE ULTIMATE TRACK OF THE SHORTWAVE MOVING FROM THE TN VALLEY TOWARD THE MID-ATLANTIC COAST THIS PERIOD. NEITHER THE ETA NOR THE GFS APPEAR TO FULLY SUPPORT ANY TYPE OF PHASING OF THE TWO STREAMS BUT STILL...HAVE DECIDED TO ERR ON THE SIDE OF CAUTION AND LEAN MORE TOWARD THE SLIGHTLY WETTER GFS...THOUGH THIS MODEL IS NOT TOO IMPRESSIVE EXCEPT ALONG THE IMMEDIATE NC/SERN VA COAST. QPF FOR THE MOST PART IS .10 INCH OR LESS BUT WITH POTENTIAL FOR RELATIVELY HIGH SNOW/LIQUID RATIOS THERE COULD STILL BE SNOWFALL AMTS OF 1-3 INCHES FROM THE CNTRL APPALACHIANS EWD ACROSS MOST OF VA INTO THE DELMARVA. SERN VA HAS THE HIGHEST POTENTIAL FOR A SIGNIFICANT SNOW EVENT WITH LIQUID EQUIVALENT QPF EXCEEDING .25 INCH. WEAK SHORTWAVE DIVING SEWD INTO THE CNTRL PLAINS BY 84 HRS BRINGS AN AREA OF LIGHT SNOW FOR WRN MN AND THE DAKOTAS EXTENDING WWD INTO THE NRN HIGH PLAINS. NRN STREAM SHORTWAVE TROF SWEEPING EWD FROM THE GREAT LAKES INTO NRN NEW ENGLAND ALSO ALLOWS LAKE EFFECT SNOW TO PERSIST. JUNKER/WOLF/MAUSSER GRAPHICS AVAILABLE ON THE WEB AT http://www.hpc.ncep.noaa.gov 24HR QP VT 16/00Z 0.01 516148 515136 513123 509108 509099 508094 498076 496072 493068 486063 481059 476051 472036 470030 467026 459008 455998 450990 443974 431955 420940 415933 410930 404927 396924 393924 391927 392935 396946 398958 399972 399982 401989 402001 404015 409026 415033 421039 422044 420048 413051 404052 397053 389058 383066 381073 384079 389083 394086 398087 407087 408093 406095 403104 397105 395108 391110 389113 389117 391120 398123 400126 403128 405126 408125 413125 415127 416133 414138 411141 405144 401148 400151 403155 405155 413152 414157 413164 413169 415175 418176 420172 422166 425169 429169 431167 429160 428147 428138 430130 431128 434128 435133 434140 434147 433154 435160 437164 442170 446173 451174 456164 461161 465161 467161 470158 471155 473148 476144 478141 483141 489145 496152 500154 503155 516148 0.01 485867 483860 480853 477846 473841 465827 461815 458808 456798 455789 452780 450775 449769 450764 447760 447755 448747 446741 445740 441739 434743 428749 426754 426759 428768 427773 421777 408781 402783 396786 390789 384794 376802 368812 363816 359821 357826 356831 355835 358836 361835 365830 368827 372826 376826 382824 390816 399808 404805 406805 409807 411812 414820 417824 421822 425819 430820 438831 441835 441839 439845 433849 426849 423849 417852 415859 417868 421872 426873 432873 437873 448872 455871 457873 459878 461887 463893 466897 469899 472899 476897 480893 482889 484883 485871 485867 0.01 390744 387736 383735 371737 359738 355740 350744 349751 353755 358761 360765 363768 364773 364778 362786 363789 365792 372788 377787 380788 384786 390781 394778 397773 396768 394766 390760 391747 390744 0.01 439088 439084 438083 436081 433083 432084 433088 433088 434088 436087 437088 438088 439088 0.01 419095 420091 418090 415091 413091 412095 415098 418097 419095 0.25 483094 483089 480085 475075 468058 464049 460037 458026 454018 444001 435984 426968 422961 416956 413955 411958 412973 413986 416998 418007 422018 432032 448064 448070 449078 451083 452090 446097 438100 434099 431101 428112 430116 433116 440115 444117 446122 448126 453128 457126 460123 466121 469119 472115 476107 483094 0.25 449812 448808 447807 444808 443811 445814 446814 449814 449812 0.25 425795 425790 423789 421791 419794 419796 419798 419802 421805 422805 422805 424802 425799 425796 425795 0.25 412068 410066 407065 407064 404062 401063 400064 400068 400072 401072 404072 405072 407072 410070 412068 0.50 472094 470091 467091 466093 467095 470096 472094 0.50 466076 465068 463064 461060 459053 457047 454043 452043 451048 453051 454056 456064 457068 459076 460084 461089 463083 464081 466076 0.50 450031 449025 447019 441011 436004 433997 432992 426984 423981 420983 421990 422994 425005 428013 431016 438024 444027 449031 450031 24HR QP VT 17/00Z 0.01 467762 464728 461711 455708 448713 440720 433722 427724 424737 425744 424754 424762 422770 420777 416783 411785 407785 403786 396790 391796 389799 388803 386810 382817 374830 370837 363845 359851 353856 344864 325884 308902 304908 299914 294921 290927 285937 279950 277956 277964 281969 288968 295967 302969 308971 315972 319972 324970 330966 333963 338961 342962 345965 353973 360976 366977 376977 382979 386981 391985 397989 400993 409006 415013 419021 421029 421034 419040 418045 416048 414049 409049 401051 396054 391061 387068 384072 387080 391085 396084 401083 406081 412079 420078 425077 430079 433081 436086 438088 438092 437099 439108 442111 447114 457120 466117 473102 475071 469038 454999 448980 445971 437946 428918 420892 418881 417869 416857 415849 413832 413822 413818 416815 420813 421809 424803 427798 434788 439781 442786 444794 442801 436811 435818 438821 442820 446817 449817 451821 452828 455839 457849 458856 457863 458870 458878 460889 463896 466900 469900 473901 477898 482892 484883 486876 486871 483860 476842 473829 472821 470806 469797 467779 467762 0.25 423953 422946 419938 415928 410917 409911 408903 407896 405888 403885 397883 395883 392883 387886 384891 376912 367929 365937 365944 367947 370950 377952 385954 401961 408966 416969 421967 422961 423953 24HR QP VT 18/00Z 0.01 536964 535942 534936 535929 532919 530913 528908 527903 521895 516892 512893 508897 504902 498913 492924 483931 473939 461944 450948 439952 432956 428959 424961 421965 419970 419978 421985 424990 431999 435001 439005 440010 440019 435047 436060 437068 439072 442086 444094 447100 451103 455101 456094 456085 456070 456062 458054 463045 467041 473038 480038 486040 492041 498043 508045 511044 514044 517041 520036 523031 524021 521012 522006 525001 529990 532983 534975 536964 0.01 473676 469668 467667 464669 460673 457680 448701 440721 429747 419757 414769 411772 407769 404758 404747 401735 395727 389724 382721 374719 370719 363721 356725 349730 341738 334745 328752 324759 319768 315777 310796 305809 302820 299828 293846 288861 285870 284880 281892 279914 281931 287938 297934 309920 314910 323898 330887 341882 357878 371872 378870 384866 391859 397852 402843 406833 409826 412814 414809 416807 423809 432815 438822 442824 445824 450821 453817 457808 461797 464786 466775 468761 471736 472724 472712 473704 473691 473676 0.01 477857 474845 470842 465840 457837 451838 446843 438849 431855 429859 430864 433867 440867 444866 448866 454866 461871 465872 470873 472872 475867 477861 477857 0.25 381754 380748 377744 373741 361737 357738 353740 346746 338757 333768 331777 331783 333788 335792 339796 346798 352799 356796 359792 361787 365781 372775 376769 379762 381754 0.50 362756 360750 356748 351750 349752 345758 343762 341766 341771 341775 343778 349778 353773 355771 358766 361761 362756