Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 201842
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
241 PM EDT WED AUG 20 2014


PRELIM DAY 1 QPF DISCUSSION
VALID AUG 21/0000 UTC THRU AUG 22/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

NORTHERN PLAINS---UPPER MS VALLEY--MID WEST INTO THE MID TO UPPER
OH VALLEY

MID TO UPPER LEVEL HEIGHT FALLS EJECTING EAST NORTHEASTWARD FROM
THE NORTHERN HIGH PLAINS TONIGHT INTO THE UPPER MS VALLEY DURING
THE DAY ON THURSDAY WILL SUPPORT INCREASING CONVECTIVE ACTIVITY
FROM THE NORTHERN PLAINS---SOUTHEASTWARD ALONG AND TO THE NORTH OF
A WARM FRONTAL BOUNDARY EXTENDING INTO THE UPPER MS VALLEY---MID
WEST INTO THE OH VALLEY REGION.  PW VALUES AHEAD OF THESE HEIGHT
FALLS AND IN THE VICINITY OF THIS FRONT WILL BE RISING TO MUCH
ABOVE NORMAL--- 2 TO 2.5+ STANDARD DEVIATIONS ABOVE THE MEAN AS
LOW LEVEL SOUTHERLY TO SOUTH WESTERLY FLOW STRENGTHENS INTO THIS
BOUNDARY.  OVERALL THERE IS FAIRLY GOOD AGREEMENT WITH THE QPF
AXES IN THE MODELS.  THE 1200 UTC AUG 20 ECMWF DID TREND SOUTHWARD
FROM ITS 0000 UTC RUN OVER THE UPPER MS VALLEY AND IS CLOSER NOW
TO THE FAVORED AXES OF THE HI RES ARW---NMM AND NSSL WRF WHICH
WERE USED PRIMARILY FOR QPF DETAILS.  HEAVY TO ISOLATED EXCESSIVE
PRECIPITATION TOTALS POSSIBLE IN A NARROW AXIS IN THE VICINITY OF
THIS WARM FRONT.  THE BIGGEST CONCERNS ARE FOR CHANGES IN THE
NARROW QPF AXIS WHICH IS POSSIBLE IF ANY ORGANIZED CONVECTION
PUSHES FARTHER TO THE SOUTH AND SOUTHEAST THAN EXPECTED AT THE
PRESENT TIME.  TRAINING OF CELLS ALONG AND NORTH OF THIS FRONT
POSSIBLE.


NORTHERN MID ATLANTIC INTO NORTHERN NY STATE


THE SURFACE FRONTAL BOUNDARY CURRENTLY MOVING THROUGH THE GREAT
LAKES WILL MOVE ONLY SLOWLY EASTWARD DAY 1 AS IT ENCOUNTERS
BLOCKING FLOW AHEAD OF IT ACROSS SOUTHEAST CANADA.  HIGH PW VALUES
AHEAD OF THIS SLOW MOVING FRONT WILL SUPPORT HEAVY PRECIPITATION
AMOUNTS FROM THE NORTHERN MID ATLANTIC INTO THE SOUTHERN TIER OF
NY AND NORTHERN NY.  THE SLOW MOVEMENT OF THE FRONT WILL ALSO POSE
RUNOFF ISSUES FOR PORTIONS OF WESTERN NY/SOUTHERN TIER OF NY INTO
NORTHERN NY WHERE THERE ARE RELATIVELY LOW FFG VALUES

NORTHERN ROCKIES INTO THE NORTHERN HIGH PLAINS

IN THE WAKE OF THE HEIGHT FALLS EJECTING EAST NORTHEASTWARD INTO
THE NORTHERN HIGH PLAINS THIS EVENING---BROAD CYCLONIC FLOW WITH
EMBEDDED SHORTWAVES WILL PERSIST ACROSS THE NORTHWESTERN PORTION
OF THE NATION.  THIS AND POST FRONTAL EAST NORTHEASTERLY FLOW WILL
SUPPORT ADDITIONAL SHOWER ACTIVITY IN A NARROW AXIS OF ABOVE
AVERAGE PW VALUES THAT WILL PERSIST OVER THE NORTHERN ROCKIES INTO
THE NORTHERN HIGH PLAINS. MODEL CONSENSUS IS FOR MODERATE TO
ISOLATED HEAVY TOTALS---WITH THE SREF MEAN USED PRIMARILY FOR QPF
DETAILS.

SOUTHEAST CA INTO THE SOUTHWEST

THE CLOSED LOW OFF THE SOUTHERN CALIFORNIA COAST IS FORECAST TO
MOVE VERY SLOWLY EASTWARD DAY 1 INTO SOUTHERN CALIFORNIA.  AT THE
MOMENT---MODEL CONSENSUS IS FOR GENERALLY LIGHT TO MODERATE
PRECIPITATION TOTALS FROM EASTERN CA INTO THE SOUTHWEST AS PW
VALUES ARE ONLY NEAR NORMAL.  DAY 1 QPF DID NOT DEVIATE FROM THIS
CONSENSUS GIVEN LOW CONFIDENCE IN WHERE LOCALLY HEAVIER TOTALS MAY
BE.


ORAVEC


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

24HR QP VT 22/00Z
 0.01 538188 538177 535165 533154 530146 526135 530122 530115
      532109 531103 528098 521089 516079 511069 506062 504059
      500058 497056 492055 491053 493051 497049 505047 518039
      524036 527033 530029 542012 543006 544000 543995 539990
      533983 526977 521971 515967 496934 485918 478902 473892
      468887 453872 448867 443860 439851 433842 428831 425822
      423814 422805 425800 428796 431793 436792 444795 450802
      454809 460816 463819 467819 475813 481804 488794 490790
      491782 490774 488768 484759 475744 469738 467724 466718
      464715 455714 439713 417721 410725 407730 404734 402738
      399740 392746 390749 388754 384758 379759 373760 370763
      374767 378769 381772 380776 379789 361818 350832 345840
      341845 343847 347849 349854 347857 348862 351868 355868
      360868 364866 380878 387882 393890 398896 401898 403906
      407926 405931 405939 405945 409952 412954 413959 410963
      407966 399972 393977 388982 387986 389991 390997 393001
      395007 399011 401014 406014 413010 420006 424004 431004
      433004 435007 437009 442017 455027 458031 452032 446033
      441033 439039 441044 442055 444065 441067 437068 433070
      431070 430074 428080 424083 420095 417099 413100 407094
      405093 402097 399101 395103 389105 386107 384108 382106
      377105 372106 368107 362107 357107 352104 345098 339089
      336086 330085 327088 324093 316097 314095 313092 312088
      309080 306072 305068 306065 308058 310054 313047 318039
      324034 324031 327028 345018 351009 354004 351000 336008
      305019 296023 290027
 0.01 290027 286030 284032 281036 275035 271034 266033 262031
      257030 253028 248027 244026 239025 234024 229025 228026
      225050 229062 226068 223077 223083 225086 230091 241100
      247102 253104 262105 271104 279103 282102 285104 291107
      296112 300114 301118 302125 304128 305133 300139 293153
      293160 294165 298164 300162 302158 303154 306153 323159
      327160 329162 338164 347165 351163 353160 363154 369151
      373143 377134 379130 382129 387124 392121 397117 403118
      407119 409124 411133 409140 410148 411153 413156 415160
      414167 417174 421175 424174 429168 432159 433150 433140
      435137 437139 444145 447148 450149 454150 456148 462144
      466145 469148 476160 483178 484197 484200 487205 490206
      493209 497216 499224 507240 511237 511234 510230 509210
      511198 514195 518196 520195 524195 532198 535192 538188
 0.01 478037 477035 476034 474036 475038 477039 478037
 0.01 405072 403065 400064 398067 394069 391068 387068 384065
      381064 378066 376071 379080 380084 382086 387088 393082
      399078 403074 405072
 0.01 323816 322812 321810 319808 315808 308806 302805 289803
      276801 251793 246796 241801 238806 236813 236820 238828
      241829 245827 248821 269826 281829 287832 289833 292837
      293843 294853 297859 301865 310871 313867 315860 318845
      320828 323816
 0.25 513147 515136 515123 513114 510105 502093 495079 490074
      484069 478066 474066 471067 467074 464082 462093 459095
      455095 448094 441096 438098 436097 431092 429093 429097
      430101 428106 424107 421109 417116 420123 423126 425127
      430120 432118 436118 442122 449126 455128 464131 470133
      476139 480144 484152 488158 495162 501162 507159 511153
      513147
 0.25 513004 514999 513994 508991 501989 494987 490984 486977
      484968 481960 479952 477945 471929 468921 464915 456906
      448896 439886 435882 431876 424860 413832 410824 408815
      407804 404797 400793 394793 388795 382800 373812 366822
      365829 367836 374850 393868 399879 407892 413903 422917
      428928 430935 432945 433955 433965 425975 422982 423988
      429987 437983 441984 445986 448992 453005 457012 461015
      473023 479024 486022 492021 498021 503019 508015 511010
      513004
 0.25 470781 469765 466754 461745 455737 448731 445729 439729
      430729 426732 422736 416743 410751 404757 400760 398765
      398770 400775 403778 408780 411777 417775 428774 436776
      441779 443781 450787 457793 461795 465795 468792 470786
      470781
 0.25 300086 294069 290061 286058 283056 274054 265051 256048
      249044 240041 235041 232043 232047 235051 236057 238067
      242074 248080 255085 262089 271093 281094 287093 291092
      300086
 0.25 271812 269810 267808 265807 264807 263806 261806 260805
      258805 256804 255805 256807 256809 256810 258811 258812
      260813 262814 264814 266814 268814 269813 271812
 0.50 503137 502134 501133 499132 498131 496131 494131 493132
      493135 493137 494139 495140 495141 497141 498141 499141
      500140 502139 503137
 0.50 489096 489093 488089 486086 485084 483082 481080 478078
      476079 475084 474086 475089 476091 478094 481096 483098
      485098 487098 489096
 0.50 476994 474983 473965 467940 463929 456920 450913 443904
      431888 425880 420870 414845 410833 405822 401812 398807
      394804 387805 383808 378816 376827 376830 378831 382834
      386838 389843 392847 391851 392858 394863 400873 410891
      415901 421909 428916 435923 438928 439934 439942 440949
      442956 441962 441970 443975 449983 453994 457004 460009
      466010 470008 473003 476994
 0.50 461775 460766 458759 453747 450741 446737 441735 435735
      428738 424741 420747 417752 415757 415762 417765 422766
      429765 434767 438770 447778 451782 455784 460780 461775
 0.50 452115 452112 451109 449107 446105 442105 440105 438107
      439110 441113 443115 445116 448117 450116 452115
 0.50 290085 292082 291077 289071 286067 280064 270059 259054
      247052 243056 243060 244064 250073 257079 262084 267087
      278091 284089 288087 290085
 1.00 467974 467967 464959 461955 457952 452949 449949 448952
      448961 449969 451976 454981 458986 460988 464988 465986
      466981 467974
 1.00 452930 451928 450926 450925 449923 448922 447923 445922
      444923 445925 445927 445928 446930 447931 448932 450932
      452930 452930
 1.00 432902 426890 420879 415868 410854 408850 402846 401845
      398846 396848 396853 398860 400867 405878 412889 418898
      422902 429904 432902
 1.00 394826 394824 392823 392824 393826 394826 394826
 1.00 275077 274075 272073 270071 267069 266068 263066 260065
      257064 255067 256069 258072 260074 262076 264078 266080
      270080 273079 275077
 1.50 420893 420886 416882 412873 410866 406858 403850 402851
      402857 404866 407875 411881 415886 420893 420893

$$





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