Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 211842
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
242 PM EDT THU AUG 21 2014


PRELIM DAY 1 QPF DISCUSSION
VALID AUG 22/0000 UTC THRU AUG 23/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR



DAY 1


MID MS VALLEY INTO THE MID TO UPPER OH VALLEY AND CENTRAL
APPALACHIANS

AN ACTIVE CONVECTIVE PATTERN EXPECTED IN THE VICINITY OF A FRONTAL
BOUNDARY AND ASSOCIATED AXIS OF ABOVE AVERAGE PW VALUES---1 TO 2
STANDARD DEVIATIONS ABOVE THE MEAN---STRETCHING FROM THE MID MS
VALLEY/LOWER LAKES TOWARD THE UPPER MS VALLEY DAY 1.  CONFIDENCE
HAS DECREASED WITH RESPECT TO THE DETAILS OF THE TIMING OF AREAS
OF CONVECTION AS THERE IS LARGE MODEL TO MODEL DIFFERENCES AND
LARGE RUN TO RUN DIFFERENCES---ESPECIALLY IN THE HI RES GUIDANCE
WHICH OFTEN WILL DEPICT THESE ORGANIZED CONVECTIVE REGIONS BETTER.
 MOIST WEST SOUTHWESTERLY FLOW INTO THIS BOUNDARY AND ENHANCED
UVVS ASSOCIATED WITH SHORTWAVES MOVING ALONG THE SOUTHERN EDGE OF
THE WESTERLIES WILL SUPPORT ADDITIONAL CONVECTIVE DEVELOPMENT
ALONG THIS FRONT.  THERE IS POTENTIAL FOR TRAINING OF CELLS IN A
GENERAL WEST NORTHWEST TO EAST SOUTHEAST DIRECTION THIS
PERIOD---SUPPORTING HEAVY TO ISOLATED EXCESSIVE RAINFALL AMOUNTS.
ALONG WITH THE DIFFERENCES IN TIMING AMONG THE MODELS---THERE IS
DIFFERENCES LATITUDE WISE WITH THE MAX QPF AXES.  DAY 1 QPF
FAVORED THE FARTHER OVERALL AXIS OF THE NAM--ALTHOUGH AMOUNTS WERE
INCREASED GIVEN TRAINING POTENTIAL.


UPPER MS VALLEY INTO THE GREAT LAKES

TO THE NORTH OF THE EXPECTED CONVECTIVE MAX QPF AXIS FROM THE MID
MS VALLEY/MID WEST INTO THE MID TO UPPER OH VALLEY---LESS
PRECIPITATION AMOUNTS ARE EXPECTED INTO PORTIONS OF THE GREAT
LAKES AND UPPER MS VALLEY.  THERE IS A LARGE VARIABILITY AMONG THE
LATEST GUIDANCE.  DAY 1 QPF LEANED TOWARD THE HI RES RUNS---WHICH
GENERALLY WERE SHOWING LESS PRECIPITATION AMOUNTS POLEWARD OF THE
FARTHER SOUTHWARD CONVECTIVE MAX.

NORTHEAST/COASTAL NORTHERN MID ATLANTIC

THE SLOW MOVING UPPER VORT AND ASSOCIATED FRONTAL BOUNDARY MOVING
EAST SOUTHEASTWARD FROM THE EASTERN GREAT LAKES---ACROSS THE
NORTHERN  MID ATLANTIC TONIGHT AND OFFSHORE OF SOUTHERN NEW
ENGLAND FRIDAY.  SHOWERS MAY REMAIN ORGANIZED AHEAD OF THIS FRONT
EARLY DAY 1---BEFORE THE SYSTEM WEAKENS AND MOVES OFFSHORE.
CONFIDENCE IS LOW WITH QPF DETAILS---WITH MODERATE AREAL AVERAGE
AMOUNTS DEPICTED.  THE HI RES GUIDANCE IS MORE EMPHATIC ABOUT
HEAVY PRECIPITATION POTENTIAL FROM SOUTHEAST NY/NORTHEAST PA INTO
NORTHERN NJ.

NORTHERN ROCKIES INTO THE NORTHERN PLAINS

THE MEAN TROF ACROSS THE NORTHWESTERN U.S. WILL AMPLIFY DAY 1 IN
RESPONSE TO SHORTWAVE ENERGY DIVING SOUTHEASTWARD FROM OFF THE
B.C. COAST INTO THE PACIFIC NORTHWEST TONIGHT AND EASTWARD ACROSS
THE NORTHERN ROCKIES FRIDAY.  MODEL CONSENSUS IS FOR TWO PRIMARY
AREAS OF PRECIPITATION WITH THIS AMPLIFYING TROF.  AN INITIAL
BATCH OF PRECIP ASSOCIATED WITH A LEAD SHORTWAVE EJECTING OUT OF
THE MEAN TROF POSITION TONIGHT INTO THE NORTHERN HIGH
PLAINS---EAST NORTHEASTWARD INTO THE REMAINDER OF THE NORTHERN
PLAINS DURING FRIDAY.  THIS WILL BE FOLLOWED BY ANOTHER ORGANIZE
AREA OF PRECIPITATION FORMING UPSTREAM ACROSS THE NORTHERN
ROCKIES/NORTHERN HIGH PLAINS IN RESPONSE TO THE MID TO UPPER TROF
AMPLIFICATION AND STRENGTHENING LOW LEVEL EASTERLY TO
NORTHEASTERLY FLOW. WITH FFG VALUES RELATIVELY LOW ACROSS THESE
AREAS---ISOLATED RUNOFF ISSUES MAY DEVELOP WITH EACH ROUND OF
ORGANIZED PRECIPITATION.

SOUTHWEST---SOUTHERN ROCKIES INTO THE SOUTHERN HIGH PLAINS

TO THE SOUTH OF THE AMPLIFYING UPPER TROF OVER THE NORTHWEST--THE
CLOSED LOW INITIALLY OFF THE SOUTHERN CA COAST WILL BE KICKED
INLAND THROUGH THE SOUTHWEST AND TOWARD THE SOUTHERN
ROCKIES/SOUTHERN HIGH PLAINS.  WIDESPREAD SHOWERS EXPECTED TO
CONTINUE AHEAD OF THIS CLOSED LOW IN A REGION OF WELL DEFINED
UPPER DIFFLUENCE AND ABOVE AVERAGE PW VALUES.  ISOLATED HEAVY TO
EXCESSIVE PRECIPITATION TOTALS POSSIBLE DAY 1 AHEAD OF THIS
TROF--ALTHOUGH CONFIDENCE ON PLACEMENT IS LOW.

ORAVEC


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

24HR QP VT 23/00Z
 0.01 536188 536174 536168 535162 525144 523133 523128 522123
      519114 514108 511106 510102 508098 505093 502090 500086
      501083 502076 503066 500060 499047 499038 498032 497020
      494010 488002 485992 482989 477988 471988 468985 461980
      458978 454978 449978 447980 441985 438986 436982 432973
      430967 431959 433954 437949 448929 451926 454928 465928
      473932 479939 490955 492957 497957 501957 505955 507953
      509949 511938 512933 512926 509921 507916 504911 505905
      507899 506890 500869 488848 478835 465822 443799 437772
      435767 434763 436761 442760 448761 452760 457757 462755
      467752 468742 469729 464720 462716 461711 470693 472688
      471685 464682 459679 457682 452683 435694 430697 427700
      416705 399714 394716 389714 381709 367703 357705 350706
      348710 342716 339722 337731 336736 336741 337747 339750
      340754 345764 350774 352780 356784 360790 364800 365807
      364811 361816 359821 357832 357844 359848 363850 366851
      369848 371852 372859 373864 375868 384880 392897 397907
      399914 398922 396927 396934 396942 395950 391961 387968
      374999 343010 314028 306034 297038 287041 278045 239042
      233047 230049 227053 226056 227059 231064 242082 247089
      250093 254097 258098 263099 268101 271104 285114 289117
      295118 302116 307117 310120 317126 322133 326141 327148
      331152 338148 342144 347143 351143 355145 360144 362143
      364140 372124 374118 374114 373111 370108 367104 367097
      371095 375094 381095
 0.01 381095 384093 389093 394094 398101 394108 389111 385113
      384116 381119 381123 387127 390129 392133 392135 394138
      397137 401137 407138 409140 408143 408148 409152 412158
      414167 418173 429170 436167 440167 442171 444174 447175
      453175 458175 461174 466175 468177 476180 476185 475187
      471197 472202 470205 464208 462210 461213 469217 473218
      478218 486220 491218 504213 516211 521206 523204 527203
      532197 536188
 0.01 312875 307846 305844 305840 305832 305825 303821 299815
      296812 292808 287806 276803 270801 270796 266793 261792
      258796 253800 245806 241811 240817 245826 249831 255832
      262833 267833 279837 286844 290848 294853 299862 301871
      303878 305882 309882 312875
 0.25 509188 506171 504169 507166 510162 511157 510154 507146
      503139 501129 500121 498113 494101 490094 487087 486083
      487077 489071 486037 482019 478013 471009 453993 451992
      447992 443995 439003 438008 439012 445016 447018 448022
      447032 447036 448041 451049 454056 457064 457070 443066
      441067 441071 444075 448081 449089 447092 444091 438093
      432094 430095 428099 426106 423111 419118 420129 423136
      425137 427135 437127 442131 443137 442140 438141 437146
      439150 444155 448157 451158 457157 465159 470158 473151
      474147 477145 484146 498154 500161 502165 501170 495180
      485188 483193 485197 489199 492199 497197 501193 505191
      509188
 0.25 451852 449843 445836 439830 432825 425821 420816 415810
      411799 408790 406784 404782 399775 393771 384770 377773
      374775 373780 374794 373805 376814 379823 382834 386844
      389851 396871 402889 404899 406912 406937 409947 412950
      416949 419946 423945 425942 426937 427925 429914 431901
      434893 437885 440875 443868 446863 451852
 0.25 443740 436721 429724 421728 413731 403733 396737 391739
      385739 380734 377732 374734 369739 368746 372749 378751
      382754 386756 391758 395759 400758 406757 414759 421755
      426753 431754 436751 438749 442742 443740
 0.25 412012 413007 413001 411998 407998 403005 399011 398015
      398021 395030 394037 396040 400039 404038 405033 407026
      410017 412012
 0.25 350123 351121 350121 349119 349118 347118 346118 345120
      346123 347123 348124 350124 350123
 0.25 319069 318064 315060 309054 305052 299051 294052 289053
      279054 269054 259052 247051 241050 237052 238056 240061
      246066 253073 258080 264087 271092 280097 285098 290098
      300095 306091 314086 316075 319069
 0.25 265819 265817 265815 264813 263811 262809 260808 258809
      257809 256810 255812 256814 257815 259817 261818 262819
      263819 264819 265819
 0.50 494138 493122 491115 489109 487101 484097 480092 476086
      473083 468083 463086 457087 453103 453107 457111 464112
      469117 476126 479131 484135 489137 492138 494138
 0.50 483067 481049 480041 478032 475026 471021 466016 463011
      458005 453001 449997 445997 444000 445008 449013 451020
      451026 451032 451042 455048 466055 475064 480067 483067
 0.50 442108 441104 435104 433107 430109 427113 425117 423123
      423126 426126 429122 431118 434116 438114 442110 442108
 0.50 427893 428882 426873 426865 427855 425846 421841 413828
      410823 408816 404798 402789 399785 393782 387783 382789
      380794 378802 376810 382821 388836 394847 397855 400864
      406898 408913 410924 412933 417937 421933 423926 425916
      425902 427893
 0.50 304076 303070 301064 297061 290060 277060 270060 263058
      258057 252058 250059 249062 253065 257069 261074 268082
      271085 277088 283089 289088 295086 299083 302080 304076
 1.00 422898 421884 421875 419867 415856 411840 406831 401818
      396808 395801 393794 390793 386794 383798 381802 380807
      381811 385823 391834 397842 403855 404861 405867 407885
      409898 411915 413921 414924 416925 419921 421914 422898
 1.50 417891 417886 416882 416878 415875 412873 410875 410880
      411884 411889 411894 412896 413901 413905 415903 416898
      416893 417891
 1.50 407850 407844 406838 403832 399823 395817 391811 385807
      384812 386818 388825 392832 396839 400845 405850 407850
 2.00 399837 399832 398828 397825 395821 393819 392817 389816
      389820 390824 391826 393828 394831 396832 398837 399837

$$





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