Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 191901
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
300 PM EDT SUN APR 19 2015


PRELIM DAY 1 QPF DISCUSSION
VALID APR 20/0000 UTC THRU APR 21/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1...

...EASTERN U.S...

THERE WAS LITTLE LARGE SCALE CHANGE FROM THE PREVIOUS FORECAST. IN
THE EARLY PERIODS WE FOLLOWED THE HRRR AND 12Z WRF-ARW IN
DEPICTING THE LINEAR CONVECTION HEADING FOR THE NC/SC/GA COASTS.
WE TRIED TO INDICATE MORE OF A BREAK BETWEEN THIS ACTIVITY AND THE
STRONGLY FORCED UPSLOPE REGIME OVER WESTERN NORTH CAROLINA. WE
THEN TURNED TO THE WRF-ARW AND THE 12Z NAM TO INTRODUCE MORE
PRECIPITATION ON MONDAY AFTERNOON INTO THE SOUTHEAST...AL/GA/SC. A
WELL DEFINED SHORTWAVE WILL APPROACH THAT REGION...AND SHOULD WORK
WITH SUFFICIENT INSTABILITY DURING PEAK HEATING TO PRODUCE
SCATTERED BUT ORGANIZED CONVECTION...DESPITE RELATIVELY DRIER MID
LEVELS. WE NOTE THE SPC CONVECTIVE OUTLOOK HIGHLIGHTING THAT AREA
AS WELL.

IN THE MID MISSISSIPPI VALLEY THE TREND WAS TO BRING PRECIPITATION
SOUTHWARD EARLY IN THE PERIOD...FOCUSING ON THE FORCING AHEAD OF A
VORT MAX IDENTIFIED IN SATELLITE IMAGERY AND MODEL FORECASTS OVER
THE KS/OK BORDER. WE PLACED PRECIPITATION FROM ARKANSAS EASTWARD
THIS AFTERNOON/EVENING BASED UPON THE 12Z NAM AND 00Z ECMWF
BLENDED WITH THE PREVIOUS WPC FORECAST...INDICATING ALSO MORE OF A
GAP IN THE 0.25 INCH AREAL AMOUNTS IN MO/IL...IN BETWEEN MID LEVEL
FORCING MECHANISMS.

OVERALL THE WPC FORECAST OVER THE EAST WAS A NEAR EQUAL BLEND OF
PREVIOUS WPC WITH 12Z NAM/00Z ECMWF AND OUR LATEST IN-HOUSE PSEUDO
BIAS-CORRECTED ENSEMBLE.

...PREVIOUS DISCUSSION...

THIS PART OF THE NATION WILL BE IMPACTED BY 2 STREAMS OF MID/UPPER
LEVEL FLOW THIS PERIOD..WITH THE UPPER MS VALLEY COMING UNDER THE
INFLUENCE OF THE NORTHERN STREAM H5 TROF MOVING
EASTWARD/EAST-SOUTHEASTWARD OUT OF THE NORTHERN ROCKIES/CANADIAN
ROCKIES..WHILE PARTS OF THE CENTRAL PLAINS OUT INTO THE MID MS
VALLEY ARE AFFECTED BY THE OPENING UP AND INCREASINGLY PROGRESSIVE
CENTRAL PLAINS CLOSED H5 LOW.  PRETTY IMPRESSIVE HEIGHT FALLS
THRUOUT THE ENTIRE REGION ASSOCIATED WITH THESE MID/UPPER LEVEL
TROFS ALONG WITH DECENT LOW LEVEL CONVERGENCE ACCOMPANYING EITHER
THE COLD FRONT OR SURFACE TROF SHOULD LEAD TO WIDESPREAD
RAINS/CONVECTION MUCH OF THE MID AND UPPER MS VALLEY BACK INTO
PARTS OF KS AND SOUTHERN NE.


THE WELL DEFINED S/WV NOW LIFTING INTO THE SOUTHEAST STATES
FOLLOWED BY THE SOUTHERN PLAINS CLOSED LOW OPENING UP AND MOVING
EASTWARD THIS PERIOD WILL LEAD TO A BACKING MID/UPPER LEVEL FLOW
REGIME FROM THE SOUTHEASTERN STATES NORTHWARD INTO THE MID
ATLANTIC STATES/OH VALLEY AND LOWER GREAT LAKES...SUPPORTING A
MODERATE/HEAVY AND POSSIBLE EXCESSIVE RAINFALL EVENT. THE LOW
LEVEL GRADIENT WILL TIGHTEN UP THE EASTERN THIRD OF THE
NATION...BETWEEN A SURFACE LOW ACCOMPANYING THE LOWER MS VALLEY
S/WV AND THE STRONG SURFACE HIGH MOVING OFF THE NEW ENGLAND
COAST..WHICH WILL RESULT IN A COMBINATION OF INCREASING GULF AND
ATLANTIC MOISTURE BEING PULLED INLAND. THE STRENGTHENING WARM
ADVECTION VIA THE STRENGTHENING LOW LEVEL JET AND THE RESULTING
RESURGENCE OF DEEPER MOISTURE/HIGHER PWATS WILL HELP FOSTER THE
WIDESPREAD MODERATE TO HEAVY RAIN FOR MUCH OF THE REGION..WITH THE
STRONGEST FOCUS FOR HEAVY TO EXCESSIVE AMOUNTS ACROSS THE UPSLOPE
AREAS OF THE SOUTHERN AND CENTRAL APPALACHIANS WHERE VERY MOIST
SOUTHEAST LOW LEVEL FLOW COUPLED WITH THE RETREATING WARM FRONT
AND LARGER SCALE FORCING SHOULD TEND TO FAVOR HEAVIER RAINFALL
RATES.  WPC CONTINUED TO LEAN CLOSER TO THE CONVECTION-ALLOWING HI
RES GUIDANCE THRU THE GULF COAST STATES/SOUTHEAST..WITH MORE OF A
MODEL CONSENSUS OF THE GLOBAL MODELS USED FARTHER NORTH INTO THE
APPALACHIANS/MID ATLANTIC STATES/OH VALLEY AND LOWER GREAT LAKES
WHERE MORE STRATIFORM RAINFALL IS ANTICIPATED.

BURKE/TERRY

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

24HR QP VT 21/00Z
 0.01 516887 515871 514865 514856 513843 511838 511831 510820
      508816 508810 506799 504787 496766 492757 490753 490747
      491741 488735 484725 479713 474705 468698 461691 456687
      448685 422680 406677 397675 392675 385677 363683 355687
      351695 347703 345708 345714 340720 333725 324734 318739
      313745 306751 301758 295765 288771 280777 275782 262792
      254798 250801 249803 250806 261815 263821 265831 262839
      261842 257844 250848 246857 243866 242874 242887 242895
      243901 244906 247909 250913 253917 257918 263918 270912
      281902 288889 294876 300861 306843 308838 311838 311842
      308854 307866 308873 310877 321866 328862 333861 333865
      327878 315887 311892 308895 305897 302899 299903 297907
      296913 294925 295930 294937 289944 287948 286950 283949
      274949 270951 266955 264958 262958 259955 254955 250955
      247957 243961 238967 235973 231984 231989 233993 243006
      248011 256015 265021 268023 270027 273028 276024 276018
      278013 278004 277999 278993 278988 281987 287983 293980
      297974 303966 309958 314952 318945 323939 332935 336933
      341936 346941 352948 358948 363950 372950 380948 388947
      395945 408938 416933 419931 425931 435929 444927 463921
      471918 479922 482932 479947 476954 471961 471964 472967
      477974 480979 482983 487982 493988 499982 502978 503972
      506963 510951 512941 514934 514927 514908 516887
 0.01 461106 451094 445092 442088 440085 441082 444078 448080
      450078 447070 442069 438067 435066 433063 430059 427056
      423054 419053 416050 412042 408037 405034 401032 396032
      394034 393040 385045 380046 376044 371036 368034 365036
      365043 364050 360052 356056 357059 360059 362060 361062
      357064 358066 360069 363068 366065 370068 372078 373083
      376086 376093 380094 385093 384090 385086 389086 393087
      395089 394093 396094 400090 401089 403090 406092 405096
      405103 405108 407110 410107 417107 426111 430109 431107
      433109 435112 438111 443111 448114 455121 457118 456113
      456109 458107 461106
 0.01 433073 431071 429068 426068 424070 421072 419074 417074
      415078 418081 420083 423084 426082 429080 430080 432075
      433073
 0.01 427101 425099 425098 424097 422096 421098 420100 422102
      423103 425102 427101
 0.01 402233 403231 403230 401228 401227 401228 399229 397228
      396228 395228 395231 397232 399232 400232 402233 402233
 0.01 387201 387197 384195 378190 373184 368183 366181 361181
      355182 351183 349185 349188 353186 362188 369192 372195
      375197 380202 384203 387201 387201
 0.01 388118 387116 385115 383115 381117 379119 377121 375123
      373125 375127 379126 381124 383122 385120 386120 388118
 0.01 349201 350199 350197 349194 348193 348192 348189 347189
      345188 345189 344191 344193 345194 345196 345198 346198
      347200 347201 349202 349201
 0.01 354120 354117 353115 349114 347112 344109 342109 342111
      343114 345114 347117 350119 352121 354120
 0.01 345076 344072 340071 338073 334077 332079 334082 337085
      338091 340094 342091 343085 344078 345076
 0.01 347057 345054 343054 341054 339055 338055 336055 334055
      332054 330054 330055 329057 330058 332059 334059 336059
      337059 339059 341059 343059 345059 347057 347057
 0.25 479902 496886 496866 492851 490840 490829 490818 490810
      490805 488801 481799 469792 467790 465785 463777 464762
      468754 471751 473747 473742 473735 471725 470721 466720
      462721 459726 452739 450742 447741 442733 440729 440725
      443717 446710 445705 441704 432701 425698 399689 394687
      391686 387687 373694 368698 362704 355720 351726 346733
      334743 328748 321752 315757 311762 303772 301777 297782
      293788 288793 281794 279790 275790 262800 259803 258805
      261806 264807 266810 268821 273828 278830 280834 280840
      278845 272849 263856 257862 253867 248875 246883 246889
      248893 253897 259900 267898 275894 279887 285875 288869
      290862 291855 293849 294840 297834 300815 307811 315812
      321811 324809 327806 331804 332807 330811 327820 324827
      324832 328834 331829 332824 339823 342825 344829 347837
      350838 353836 359834 361836 361841 361845 365843 370842
      373845 375851 378862 377866 374870 368875 366882 362884
      359883 356878 354877 350876 346875 342877 338882 333890
      330898 332901 337901 343904 342911 346917 351918 355921
      358923 361923 365922 370922 375921 378918 381911 383902
      386889 386881 389873 392864 401861 406853 411859 415865
      416874 410887 406894 403904 402913 402918 405921 409923
      417922 431920 479902
 0.25 431094 429093 429094 431094 431094
 0.25 409061 408058 406056 404055 400055 397054 393055 394059
      393064 394067 398067 399064 401062 403061 407062 409061
 0.25 372053 370052 368052 370053 372053 372053
 0.25 268997 267988 266980 263973 260971 256970 250970 244974
      240979 238987 242994 247997 255000 262002 266001 268998
      268997
 0.50 461867 453856 454848 458842 464835 470829 473825 472819
      464811 462811 459808 457803 453795 452789 452784 453777
      452768 452765 449763 445762 439760 435761 433766 431773
      429778 427779 422771 421764 424761 425755 428751 433749
      436744 432733 433726 433720 431716 428712 424708 421706
      417704 406705 403705 399703 395694 390691 385694 377701
      367710 362719 357727 353734 348741 341748 334755 323758
      318762 314766 307775 303783 299790 299795 302797 310801
      314800 321797 325795 331792 337792 344790 349789 352792
      356801 355810 356814 359816 367814 376808 399800 409802
      412804 415809 418817 418824 418829 417834 417841 419847
      423850 425857 427863 425871 424874 425877 426879 429879
      434876 436872 440869 449869 452872 454878 453883 450890
      445896 436902 429903 425902 424898 419898 413903 413909
      413915 418916 423916 429916 435914 444911 453906 462898
      464892 469889 472885 473878 471870 469867 461867
 0.50 367900 367898 364896 362895 360897 358899 358903 359905
      360907 361912 364912 365909 366907 367903 367900
 0.50 287827 287825 287824 285823 283824 283825 283827 285828
      287827 287827
 0.50 276805 275803 272801 272799 270801 269804 268806 269810
      271812 273814 273816 273814 273810 274806 276805
 0.50 277875 278870 275868 273859 271859 268861 264867 261873
      257878 255882 255887 259893 265892 269890 272888 276882
      277875
 0.50 261996 262990 261984 260980 257976 253975 249976 246978
      243982 242986 244990 247992 251994 255996 258997 261996
 1.00 434816 434814 434811 434809 433807 433806 431805 429806
      428807 428808 427810 427812 426814 426815 426817 427819
      429821 430820 432820 433819 434817 434816
 1.00 419731 418722 416717 412719 405721 394725 386718 378712
      375714 373716 370721 366725 364729 365735 367737 371738
      376739 379743 376750 373756 375767 373774 370779 366789
      365791 365796 369801 375800 381798 391792 401789 411782
      413779 412775 411768 412761 414755 417749 418743 419731
 1.00 255990 255988 255986 255984 255982 253980 252981 250982
      249984 249986 250986 251987 252988 253990 254990 255990
      255990
 1.50 409744 410742 409741 408740 407739 405738 403738 401738
      400739 399740 400740 402741 404743 405745 406746 408746
      409744 409744
 1.50 406778 406777 404776 403776 402775 400775 398775 397777
      397779 399781 399782 401782 403782 404781 405780 406779
      406778
 1.50 399763 399761 399760 397759 395759 393759 391759 390760
      388761 387763 387765 388767 389769 391771 393771 394770
      396769 397768 398767 399765 399763
 1.50 386786 386783 385782 383782 381782 380784 379784 378785
      376786 375787 375788 373789 372790 373792 373793 375793
      377793 379793 380792 381791 382790 384789 384788 385787
      386786

$$





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