FXUS04 KWBC 270716 QPFPFD QUANTITATIVE PRECIPITATION FORECAST DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 214 AM EST SAT MAR 27 2004 PRELIM DAY 1 AND DAY 2 QPF DISCUSSION VALID MAR 28/1200 UTC THRU MAR 29/1200 UTC REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR DAY 1... PLAINS/MID TO UPR MS VALLEY... THE DEVELOPING HEAVY PCPN EVENT OVR THE NRN HIGH PLAINS EARLY THIS MORNING WL EXPAND TO COVER A LARGE PORTION OF THE PLAINS DAY 1 AND PUSH TOWARD THE MID TO UPR MS VALLEY. MODELS ARE IN GENERAL AGRMNT THAT MID LEVEL HTS WL FALL SGFNTLY ACRS THE MID SECTION OF THE NATION DAY 1 AS THE LONGWAVE TROF PROGRESSES EWD FROM THE ROCKIES. ABUNDANT MOISTURE IS EXPECTED TO CONT TO STREAM NWD AHEAD OF THE ASSOC CDFNT FCST TO PUSH EWD THRU THE MID SECTION OF THE NATION WITH THE FALLING MID LEVEL HTS. BOTH THE ETA AND GFS SHOW WELL DEFINED BNDRY LAYER CONVERGENCE WITH THIS FRONT. DAY 1 QPF WAS MODELED CLOSELY TO THE BNDRY LAYER CONVERGENCE AXES...WHICH OFTEN DEPICT POTENTIAL FOR A WELL DEFINED CONVECTIVE LINE ACRS THE PLAINS...DEPICTING A LARGER AREA OF 1"+ RAINS THAN BOTH THE OPERATIONAL ETA OR GFS. SEVERAL OF THE ETAKF SREF MEMBERS WERE USED TO DEPICT QPF POTENTIAL ALONG THE EXPECTED WELL DEFINED SQUALL LINE. SOME SGFNT CHANGES TO MODEL QPF ALSO DEPICTED OVER THE SRN PLAINS FROM WRN KS INTO A LARGE PORTION OF OK. HERE .50-1"+ AREAL AVG AMTS WERE DEPICTED...SIMILAR TO AMTS EXPECTED ALONG THE LENGTH OF THE COLD FRONT FROM THE NRN PLAINS/UPR MS VALLEY SWD INTO THE CNTRL PLAINS AND MID MS VALLEY. WITH MODELS SHOWING WELL DEFINED BNDRY LAYER CONVERGENCE ACRS THIS AREA...ABUNDANT MOISTURE IN PLACE AND INCREASING UPR DYNAMICS PUSHING ACRS THE REGION...BELIEVE MODELS ARE DEFICIENT ON THE WRN EDGE OF THE PCPN SHIELD. PAC NW/NRN ROCKIES... PCPN SHOULD BE WINDING DOWN ACRS THE PAC NW AND NRN ROCKIES DAY 1 AS THE LONGWAVE TROF PUSHES EWD INTO THE MID SECTION OF THE NATION AND SFC TO MID LEVEL RIDGING PUSHES EWD ACRS THESE AREAS. BEST CHANCES FOR PCPN WL BE ACRS THE NRN ROCKIES ACRS NWRN MT AND NRN ID INTO SAT AFTERNOON WHERE .25-.50"+ AMTS ARE POSSIBLE. ACRS THE PAC NW....10-.25"+ AMTS POSSIBLE IN FAVORED TERRAIN OF THE WA/OR CASCADES. ERN NEW ENGLAND/MID ATL.... SFC CDFNT SHOULD CONT TO PROGRESS STEADILY EWD OFF THE NEW ENGLAND COAST SAT AND SWD INTO THE MID ATL. THE WELL DEFINED AREA OF PCPN PRESENTLY MOVG THRU NEW ENGLAND WL AFFECT EXTREME ERN NEW ENGLAND EARLY SAT BEFORE MOVG OFFSHORE. PCPN AMTS EXPECTED TO BE LIGHT ACRS ERN NEW ENGLAND. GENERALLY LIGHT PCPN AMTS ALSO EXPECTED THRU THE MID ATL INTO THE CNTRL APPALACHIANS AND OH VALLEY...WITH AMTS DEPICTED AS GENERALLY LESS THAN .25". THE MOST SGFNT WEATHER ASPECT HERE WL BE THE DECREASE IN TEMPS TO THE EAST OF THE APPALACHIANS AS SFC RIDGING WL PUSH THE BACK DOOR CDFNT SWD. DAY 2... ...GRT LAKES/MIDWEST/LWR MS VLY... FULL LATITUDE TROFFING WL PUSH SLOWLY EWD FRM THE PLAINS INTO THE MS VLY THIS PD...ALLOWING A CDFNT TO SWEEP EWD AND FOCUSING A BROAD AREA OF SIGNIFICANT CONVECTION AND HEAVIER RAINFALL. SHD SEE PLENTY OF ACTIVE CONVECTION FRM DAY ONE SUSTAIN ITSELF OUT OF THE PLAINS AS DEEP MOISTURE/INSTABILITY SURGES NWD FRM THE WRN GULF OF MEX. THE ETA AND GFS BOTH SUPPORT THE UPR TROF TAKING ON A NEG TILT AS WELL WITH IMPRESSIVE UPR DIFF/FORCING OVR ESP THE MIDWEST/UPR MS VLY/WRN LAKES REGION. XPCT MDT/HVY RAINFALL TO SWEEP THRU THIS REGION WITH MCS ACTIVITY LIKELY. THE H8 FLOW ON BOTH THE ETA AND GFS GRADUALLY WANES ACRS THE LWR MS VLY...BUT THE DRAPING CDFNT SHD STILL ACT TO FOCUS SUFFICIENT CONVECTION FOR LOCALLY HVY RAINFALL...AND ESP GIVEN BETTER INSTABILITY. THE OVERALL TREND IS FOR A SLOWER EVOLUTION OF THE UPR TROF...SO HAVE TRENDED TWD THE SLOWER GFS ESP LATER IN THE PD VS THE ETA. MANUAL PROGS FAVOR GENERALLY AN ETA/GFS BLEND WITH 1 TO 2 INCH AMTS LIKELY. WHILE HVY RAINFALL IS LIKELY GIVEN SUCH STG HEIGHT FALLS/FORCING...THE GFS IS SUFFERING FRM SOME CONVECTIVE FEEDBACK AND THUS MAY BE OVERDOING SOME OF IT AMTS LOCALLY. ...N CENT PLAINS... A POCKET OF VRY COLD AIR ALOFT ASSOC WITH THE DEEP UPR PLAINS TROF COMBINED WITH SOME ADDITIONAL S/WV ENERGY DROPPING SEWD WL BE GENERATING A SWATH OF INSTABILITY. GIVEN SOME OF THE RECENT RAINS OVR THE REGION...LOW LVL MOISTURE SHD BE RELATIVELY ENHANCED SUCH THAT THE SOME SCT SHWRS/TSTMS WL DEVELOP. THE DAYTIME HEATING EARLY IN THE PD WL BE THE MAJOR PLAYER....AND THE CONVECTION SHD WANE AFTER SUNSET. MANUAL PROGS LEAN TWD THE ETA SOLN. THE GFS PROMOTES A FULL FLEDGED MCS WITH A STG VORT AND GENERATES RATHER HVY AMTS. NOT SEEING ANY REASON TO FAVOR HVY RAINFALL WITH THIS EVENT GIVEN THE LOW PWS OVERALL AND PROGRESSIVE NATURE TO THE CONVECTION. ...SRN MID-ATL... A FRONT SINKING SWD EARLY WL STALL OUT AND MAY HELP FOCUS SOME SCT CONVECTION. FORCING IS RATHER WEAK THOUGH...BUT SOME ERLY FLOW INTO THE UPSLOPE AREAS OF WRN NC MAY HELP ENHANCE THE ACTIVITY SOMEWHAT. MANUAL PROGS BLEND THE ETA/GFS. ...SRN NEW ENGLAND/DELMARVA... MORE OF AN ERLY FETCH WL BE SETTING UP HERE WITH TIME AND THAT MAY HELP TO BRING IN A FAIR AMT OF LOW CLOUDS AND DRIZZLE. THE ETA AND GFS SUPPORT LOW PRESSURE LINGERING OFF THE COAST...HELPING TO ENHANCE AN ONSHORE COMPONENT. WENT WITH THE ETA AND GFS SOLNS OF GENERATING SOME VRY LGT RAIN/DRIZZLE THIS PD HERE. ORAVEC/ORRISON GRAPHICS AVAILABLE ON THE WEB AT WWW.HPC.NCEP.NOAA.GOV 24HR QP VT 28/12Z 0.01 494614 483600 479594 475592 468591 464593 461596 455603 449610 442618 437626 430633 423640 418647 377707 333748 324761 322773 326787 332803 338812 347823 368844 373856 375866 377877 381887 383885 384887 385892 383899 381903 378906 373910 353930 348935 343941 338947 334955 327970 324976 320983 311990 305994 302998 297014 300019 305020 309018 316016 324014 330015 337014 342015 347014 352015 356016 360016 368014 376016 385016 394016 399016 401017 410018 418017 434016 444014 489007 510002 524989 532969 535945 516899 479882 440854 415841 412838 407833 404828 402822 400811 399801 400792 401782 401778 403774 408759 409754 412748 417741 427725 431718 436711 447700 458687 471671 483654 485650 489643 492638 493632 494614 0.01 536211 536201 535191 534188 531179 527170 523163 518157 512152 506147 482125 478122 476112 474103 472101 467100 461097 455091 454078 452069 449062 445058 442056 438055 433058 429064 430071 432073 439074 442076 444081 445084 442087 437090 430084 424083 421088 423098 420106 415111 412110 410099 406100 403106 400110 400114 403118 409120 413120 417121 419125 422131 425132 427131 431126 435124 437128 436130 431137 430140 426140 422140 419142 415148 412151 409150 401149 414175 416181 419184 422182 426176 431170 439173 441177 439183 441190 449196 451199 454196 457194 458190 468180 470179 474178 479180 482183 495192 504193 509199 520211 532214 533214 536211 0.01 522265 524255 522249 520244 517239 514234 509226 502215 497208 489201 486200 483200 478202 474204 466205 456206 450211 447212 440212 437214 434213 429207 424202 421201 420205 423210 422221 424226 423230 417228 417221 416216 410214 407211 402211 400216 401220 400224 396226 391225 389225 386227 385230 386233 387236 391240 400246 402248 407249 416252 425251 444253 462255 473256 483259 489264 491267 496276 500286 502291 507292 513286 517278 519273 0.01 416072 417066 415061 412057 407052 398051 392055 387060 384065 384072 387079 391087 394088 397087 402083 409080 414076 416072 0.25 483620 481612 477609 474608 470609 462613 454621 440635 422656 418678 416687 417691 424698 433691 472648 482638 484630 483620 0.25 409012 461006 506991 515979 520956 513941 475912 431898 413898 372927 346950 324994 325997 334004 354007 359009 370008 396010 405012 409012 0.25 514180 513174 510170 505165 500163 493162 487158 482153 478146 476143 476137 463136 456140 453147 449155 449159 452161 457161 461162 467166 475168 484171 489175 495175 507183 511183 514180 0.25 482218 484214 482211 479210 476212 473214 472215 473216 475218 478217 481218 482218 0.25 465221 463218 461217 458217 455217 453218 454220 457221 459224 459225 461225 463224 465221 0.25 448225 451221 449218 446218 443219 442219 442222 442223 445225 447225 448225 0.25 448113 447109 447108 444105 443105 441104 439104 438108 441110 443113 443114 446114 448113 0.25 380809 380805 378802 374801 372803 369805 369806 370810 372812 372813 375813 378813 380811 380809 0.25 359754 358751 354750 352753 352754 351758 351759 350763 351766 351770 352773 353776 355779 358778 359773 359769 360765 360761 359758 359756 359754 0.50 473630 470622 468619 462622 457626 450635 447639 439649 433660 428668 427674 430679 437676 460655 467647 471641 474634 473630 0.50 505976 506966 503960 496951 490945 483939 475932 467927 453918 443914 434913 425911 420911 415914 398926 393927 388931 380933 376934 354945 345957 338973 333990 343998 353998 368999 388001 398005 427006 445003 466999 477997 488993 494991 498989 500986 505976 0.50 479159 476158 473155 472154 470151 469149 468147 465146 462147 461148 460152 461154 463157 464158 467160 470161 473162 476162 479160 479159 1.00 366976 375980 383986 413994 454989 479988 488985 490975 481969 469969 452973 442974 435971 434968 437960 444955 453947 454938 447929 437925 416928 390939 367950 361951 348961 344971 343976 349977 359975 366976 1.50 416971 417967 416965 413964 410962 407964 407965 404968 404970 405972 405973 408974 411975 414975 416971 416971 24HR QP VT 29/12Z 0.00 556844 546881 535926 515943 494954 480972 0.01 473812 442815 415821 388823 365815 349800 343765 333766 324782 319801 331823 354840 352851 335865 325876 309896 296921 287957 286996 294009 308006 319980 338973 379972 404000 426042 443056 452030 447005 428980 411949 403926 414925 453964 492973 530966 556913 555843 534810 500811 473812 0.01 426695 423687 421684 417683 411684 406688 403694 401699 401703 402709 401714 398719 396724 395733 397740 401742 405741 408737 413728 416719 421715 424709 426699 426695 0.01 464136 464131 463130 460128 457129 454128 453130 452134 454138 456139 457139 460140 461139 463137 464136 0.01 463106 462101 458100 455097 453094 449093 444097 438096 437098 438104 435109 442113 446121 449121 456118 460110 463106 0.01 399771 394766 385766 376767 372766 372762 370755 367752 363751 358752 355757 354761 357767 360769 364771 366777 368781 372783 381785 385785 390783 396780 400775 399771 0.01 416064 412061 410059 407057 404057 402061 401064 399068 396072 396076 397079 398079 403076 405076 407078 409076 411076 413076 415072 414068 416064 0.25 543891 542872 540864 538857 535848 529841 522837 515835 502833 473830 457830 443831 425833 410836 394841 386843 382846 381848 379853 377856 371858 362859 355864 348869 342875 333884 324895 319901 315907 309919 304933 302942 301950 302961 303965 306967 310966 313964 318959 327950 333947 339951 342953 346954 351954 355952 360948 366941 374931 386918 397908 404903 412898 417898 421898 424899 426901 436915 448926 458938 468948 476953 482956 490957 499957 509954 517950 523945 528939 534927 539914 542901 543891 0.50 469933 485940 513938 530910 529872 514853 480842 451837 428836 408847 392863 379878 356900 342911 333913 331904 319912 308939 310949 324939 339939 351940 367930 378919 382914 388909 403897 410893 421890 429888 436888 448886 455887 458888 462892 463897 461899 453901 449902 446904 445908 446914 451920 458925 465930 469933 1.00 380893 370901 359913 357919 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