Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 220727
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
327 AM EDT TUE AUG 22 2017


PRELIM DAY 1 QPF DISCUSSION
VALID AUG 22/1200 UTC THRU AUG 23/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1...

...WIDESPREAD MOD-HEAVY RAINFALL AHEAD OF A SHARPENING COLD FRONT
FROM THE SOUTHERN PLAINS THROUGH THE LOWER-MID MS VALLEY...OHIO
VALLEY...EASTERN GREAT LAKES...AND NORTHEAST...

VIGOROUS NORTHERN STREAM SHORTWAVE PIVOTING ACROSS THE UPPER MS
VALLEY AND GREAT LAKES THIS PERIOD WILL ALLOW FOR TROUGH
AMPLIFICATION/HEIGHT FALLS ACROSS THE NORTHEAST
SECTOR...ULTIMATELY LEADING TOWARD A CUTOFF MID/UPPER LOW INTO
SOUTHERN QUEBEC BY THE END OF THE PERIOD (12Z WED). GIVEN THE
DEGREE/DEPTH OF SYNOPTIC SCALE FORCING...THE MODELS ARE FAIRLY
WELL CLUSTERED WITH THE SURFACE LOW TRACK INTO SOUTHEAST
ONTARIO-SOUTHERN QUEBEC ALONG WITH THE ASSOCIATED ELONGATED COLD
FRONT...THOUGH SLIGHT TIMING DIFFERENCES REMAIN WITH THE
PROGRESSION OF PRE-FRONTAL CONVECTION. BASED ON THE LATEST MODEL
TRENDS...PARTICULARLY WITH THE ENSEMBLE OF HIGH-RES CAMS AND
PARALLEL VERSIONS...WPC INCREASED QPF TOTALS ACROSS PORTIONS OF
THE LOWER AND EASTERN OH VALLEY INTO THE NORTHEAST...ESPECIALLY
FROM EASTERN KY...WESTERN PA...AND MUCH OF NY INTO NORTHERN NEW
ENGLAND. LOW-LEVEL FRONTOGENESIS AHEAD OF THE TROUGH WILL BE MOST
FAVORABLE OVER THESE AREAS...WHILE COUPLING WITH AN IMPRESSIVE
PRE-FRONTAL THERMODYNAMIC ENVIRONMENT AS MIXED LAYER CAPES PEAK
BETWEEN 1000-2000 J/KG ALONG WITH PWs OF 1.75-2.00 INCHES. THE
HEAVY RAINFALL SIGNAL IS FURTHER SUPPORTED BY THE UPTICK IN
LOW-LEVEL MOISTURE POOLING (850 MB SOUTHWESTERLY FLOW 45-55+ KTS
PER THE MODELS) AND ATTENDANT NOTEWORTHY MOISTURE FLUX ANOMALIES
(4-5 STANDARD DEVIATIONS ABOVE NORMAL).

THE PROGRESSIVE NATURE OF THE FRONT REMAINS THE MAIN INHIBITOR TO
THE EXCESSIVE RAINFALL POTENTIAL. HOWEVER...THE AFOREMENTIONED
UPTICK IN SOUTHWESTERLY INFLOW LATER THIS AFTERNOON-EVENING
(UPWIND PROPAGATION) MAY ALLOW FOR SOME CELL
TRAINING...PARTICULARLY OVER WESTERN PA INTO WESTERN-UPSTATE NY
AND NORTHERN VT-NH. A "SLIGHT" RISK WILL BE NOTED ACROSS THESE
AREAS AND INTO EASTERN PORTIONS OF THE OH VALLEY (WITH THE HIGHER
ANTECEDENT SOIL MOISTURE/LOWER FFG) IN THE NEW DAY 1 EXCESSIVE
RAINFALL OUTLOOK (ERO).

ACROSS THE SOUTHERN PLAINS -- PARTICULARLY ALONG AND JUST NORTH OF
THE RED RIVER INTO CENTRAL AR -- THE MODELS CONTINUE TO DEPICT A
SIGNAL FOR HEAVY RAINFALL ALONG AND SOUTH OF THE FRONT WHICH WILL
BECOME DRAPED MORE OR LESS IN A W-E FASHION. GIVEN THE FRONTAL
ORIENTATION AND ANTICIPATED LOW-LEVEL AND MEAN LAYER
FLOW...CHANCES FOR CELL TRAINING ARE HEIGHTENED OVER THIS REGION
AS NOTED BY THE WEAK MBEs/CORFIDI VECTORS LATE TUE INTO EARLY WED
(5 KTS OR LESS). WPC WILL INCLUDE A "SLIGHT" RISK OVER THIS REGION
AS WELL IN THE DAY 1 ERO.


...SOUTHEAST...

CONDITIONS SHOULD SLOWLY BECOME MORE CONDUCIVE TO NUMEROUS
THUNDERSTORMS ALONG THE GULF AND ATLANTIC COASTS AND PARTS OF
FLORIDA. AN EASTERLY PLUME OF MOISTURE AND CONVERGENCE WILL
STRETCH OUT FROM LOUISIANA TO THE CAROLINAS ON TUESDAY...WHILE
MOISTURE INCREASES ALSO INTO SOUTH FLORIDA AHEAD OF THE NEXT WAVE.
WPC BLENDED THE PREVIOUS FORECAST WITH UPDATED VERSIONS OF THE
WRF-ARW AND NSSL WRF AND OUR IN-HOUSE ENSEMBLE...RESULTING IN A
FEW POCKETS OF AREAL AVERAGE HALF TO ONE INCH AMOUNTS THROUGH 12Z
WEDNESDAY. LOCAL HEAVIER DOWNPOURS ARE EXPECTED.


GRAPHICS AVAILABLE ON THE WEB AT WWW.WPC.NCEP.NOAA.GOV

BURKE/HURLEY


24HR QP VT 23/12Z
 0.01 487614 490615 493619 497628 502636 506641 513658 514669
      516679 523701 526716 528724 528728 529744 529758 529783
      535830 535842 532850 525860 522864 517864 508862 504862
      500860 493856 486851 483847 482844 477836 471839 459849
      453854 446859 427878 422884 416891 410899 405908 392940
      378973 372988 368994 364998 362002 362009 363016 365021
      370027 373030 375035 378040 382041 391043 397046 401048
      403051 407053 409057 411061 410066 410070 407072 403075
      401079 399082 400085 397088 393086 390086 386092 381098
      377101 375099 372098 374092 372087 369084 368080 365078
      362075 358076 349079 345079 343079 341083 344092 345101
      339105 336102 334102 332103 328107 326109 322109 319110
      315110 310106 307102 303106 294108 289106 285103 285098
      283093 276089 268085 257077 251071 247066 247060 250058
      259058 266057 270056 270054 276057 284059 289057 293055
      296050 296046 299037 303029 316020 322003 327933 333911
      335903 336892 337880 341871 343863 345853 348844 346840
      346835 348826 352820 359809 363804 365802 368803 373801
      376797 381789 386781 389773 391769 392764 394754 394743
      397735 398731 397723 396712 399704 403697 411686 416682
      421676 430663 437654 439650 443647 452643 463639 469635
      474629 479623 483615
 0.01 527252 522249 520246 512240 506234 504230 501225 498221
      497222 495227 496232 500242 501246 501254 497254 493252
      485253 474267 468274 461278 459282 460287 466287 472283
      476279 478274 482267 491272 506283 514287
 0.01 530024 531016 531010 526999 522991 517986 510980 507982
      506988 507993 508999 512009 516018 520028 525031 529029
      530024
 0.01 438209 439201 438197 434196 431196 425195 422194 421192
      418187 417182 416177 417169 419166 419162 417156 414152
      408151 405148 401145 396144 391139 387136 383139 382142
      385147 388156 390166 391170 396171 398169 401171 405175
      407185 412190 413195 416199 418205 416211 413212 411209
      411204 409201 405199 397194 385189 369181 364179 360179
      360183 362187 369193 376198 383203 391209 396212 398215
      405220 408221 410223 406225 402226 399227 398229 399232
      401233 404236 412236 419230 424222 430214 436211 438209
 0.01 410115 411108 410105 410099 408093 406093 404097 402099
      397101 396096 394094 392096 390100 387104 386109 380112
      374118 370119 365118 362116 358115 353115 352119 360132
      363135 367135 372136 376135 383133 389128 394123 397120
      402123 404123 406121 410115
 0.01 387707 386703 384701 380701 373703 370706 359720 352728
      350733 343737 340740 336745 333749 332754 326776 319782
      312787 307790 300791 288793 281786 276784 270783 251787
      241785 238785 234786 228788 226794 230802 232808 231815
      230820 230826 231839 234851 238854 243853 246852 251851
      259845 264843 267842 270843 278843 281846 283848 286848
      290851 288863 286868 282872 275877 268878 265880 262885
      260888 260896 261927 259931 255935 247941 242946 239954
      237961 235964 235969 238975 242980 247983 252984 257982
      259978 260975 263974 272975 279973 281975 286975 293968
      299957 305946 309937 316915 319905 321895 323889 325883
      328870 328864 331859 338850 340845 339843 337841 330843
      324844 319844 317840 321832 322826 325822 330818 334814
      345796 347783 352774 355770 356766 355754 358748 360744
      367736 375727 383718 387707
 0.01 367160 367158 366157 365155 365154 363154 362154 361155
      360156 361157 361159 362160 364161 366161 367160
 0.01 305810 303807 298807 289808 286814 279819 274822 274825
      277828 282833 290834 292835 295836 297834 296824 299817
      304812 305810
 0.01 282962 282960 281958 280960 279960 278962 278964 278966
      278968 279970 280968 281966 281964 282962
 0.25 524831 524825 521821 519816 517811 517806 517797 516779
      515769 514767 511768 505772 502775 500774 497767 495763
      493761 489756 486748 485739 486730 488721 491715 495709
      498708 499711 501718 504724 509725 513720 514716 514710
      513696 511684 509674 506663 503657 499652 496644 491639
      488638 485640 480645 477649 473655 468658 465661 461666
      457674 454681 449688 443692 433702 425711 416722 409733
      404744 403750 404756 406764 408768 408773 405778 399783
      392789 387792 382799 378805 375812 372817 366829 359853
      356859 354870 354879 353883 351886 348889 346893 344900
      341915 339921 335927 333934 336939 339945 339949 338956
      335962 332969 330976 329981 329987 331996 332004 329012
      325018 324025 325033 328040 336049 346053 354060 358062
      362061 365056 371053 380054 380051 379050 375048 372047
      369043 362032 355027 356020 358002 360988 364977 367970
      367965 366961 365953 366943 368938 368941 368946 370950
      372952 377952 382947 385940 386933 387923 386913 385905
      386900 388897 394898 397897 398894 405878 412866 430847
      448828 458820 466815 472810 479809 483808 486808 493811
      500827 504832 508836 513838 517838 522836 524831
 0.25 456658 456655 455654 453656 453659 452660 452661 452664
      453664 454663 454661 455660 456658 456658
 0.25 381195 381193 381192 380191 378190 376189 375188 373187
      371187 370188 371189 372190 372191 374192 376193 377193
      378194 379194 381195 381195
 0.25 386070 384064 378062 371061 366061 364064 361064 360065
      364067 367068 373070 374075 375079 377082 380081 382078
      385072 386070
 0.25 336797 334796 334793 332791 330792 325799 320804 320806
      323808 317811 314813 312816 311821 313825 320823 324816
      328810 333806 336799 336797
 0.25 336058 337056 336054 334052 332052 331052 329052 328053
      327053 325055 326057 327058 328059 330059 332060 334059
      336058 336058
 0.25 303089 304083 301079 294074 286070 276069 267068 264072
      269075 276079 282084 288089 291092 292098 295099 298097
      303089
 0.25 304886 305881 304877 301871 296874 292881 291887 285890
      282896 282904 283910 285918 288925 291926 293929 295935
      297937 300937 303932 304927 304922 299920 295912 294905
      295897 296893 299892 304888 304886
 0.25 282802 281796 278792 274789 269789 258793 253794 249796
      248801 248808 249813 250820 252825 256830 260831 265831
      268831 268828 265823 264819 267814 269810 274808 278806
      282802
 0.50 510705 509693 507683 506674 504669 502666 498667 495670
      490680 485686 481691 478682 472680 469679 470676 471668
      470666 467666 463670 457682 454688 449692 444696 440699
      433708 417730 415736 414740 410742 406748 408754 410756
      411760 412769 411777 407782 391795 387799 383806 381812
      377819 372824 369831 366845 364853 362859 361868 361877
      358888 353898 349903 346910 345918 342925 339933 340939
      344945 343953 337965 335971 334981 334989 336994 338999
      339006 336020 334029 333036 339043 345045 351048 355053
      356056 360056 363051 365047 364042 360038 352041 348039
      345038 343035 341030 341028 344027 346028 349028 352021
      354013 356995 355985 358978 362972 361963 358958 357951
      361924 364910 368895 373880 375870 375862 391842 401822
      406818 413817 422809 428807 431805 432801 434790 436782
      440775 443771 449768 453770 457771 455776 450785 447792
      445798 444802 445808 449812 454812 458811 464807 472798
      476792 479787 481778 482770 475740 474734 477727 479721
      483715 487707 492700 497696 499695 501697 505707 507710
      509709 510705
 0.50 516809 516806 515804 515801 514798 513796 511796 510797
      508799 508800 507801 506802 506805 506808 506810 508812
      508813 509814 511814 513813 514812 515811 516809 516809
 0.50 382934 383929 383925 382920 380918 377920 376922 375927
      375929 375934 375938 375940 377944 380943 381940 382936
      382934
 0.50 323814 321814 321815 323814 323814
 0.50 298086 297081 294079 289077 285075 282073 277073 278078
      282080 286082 289085 292087 295088 298086
 0.50 274799 271795 266793 260795 253797 251802 252810 255816
      257817 261816 264811 265806 270802 274799
 1.00 469769 467769 466771 465774 463777 462780 461783 460785
      459789 459792 462790 464788 465784 466782 467779 468776
      469771 469769
 1.00 450701 449698 446699 443703 439708 435713 430724 430732
      428740 424752 424760 425765 427767 432767 437763 443752
      445747 446742 445737 446731 449724 450718 451714 450709
      450701
 1.00 424787 424783 420781 414786 409791 402795 399801 397804
      398807 403803 405801 408801 415803 420799 422796 424791
      424787
 1.00 388831 388826 386824 385825 382827 380830 378832 377835
      376837 377839 380840 382839 385836 386834 388831
 1.00 360047 361045 360043 358043 356043 355044 355047 356049
      358050 360049 360047
 1.00 354949 354947 354945 354943 354941 352939 352938 350937
      348938 348939 348941 348943 348945 348947 348949 348951
      348952 350954 352952 353952 354951 354949
 1.00 350000 350998 350996 351993 349992 349991 348990 346991
      345993 345995 345998 346999 346000 347002 347004 347005
      348004 349002 350000
 1.00 350971 351967 351963 350959 348958 346959 345961 343964
      341967 340969 340973 341976 344977 348976 350974 350971
 1.00 348925 349923 348921 348923 348925 348926 348925
 1.00 258803 257803 256803 256804 258804 258803
 1.50 444713 444709 441711 439714 438717 437719 436722 436727
      435729 436733 439732 441730 442725 442723 443718 444715
      444713
 1.50 440748 440743 439740 437738 435739 433742 432745 431748
      430752 431757 434758 437756 438753 440750 440748

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