Quantitative Precipitation Forecast
Issued by NWS

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FXUS04 KWBC 201846
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
245 PM EDT MON MAY 20 2013


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


DAY 1

MID MS VALLEY INTO THE SOUTHERN PLAINS

THE SURFACE FRONTAL BOUNDARY CURRENTLY STRETCHING FROM THE CENTRAL
TO SOUTHERN PLAINS WILL BECOME VERY SLOW MOVING FROM THE SOUTHERN
PLAINS INTO THE MID MS VALLEY REGION THIS PERIOD.  STRENGTHENING
SOUTHERLY TO SOUTHWESTERLY LOW LEVEL INFLOW INTO AND AHEAD OF THIS
BOUNDARY WILL RAISE PW VALUES TO 1.5-2 STANDARD DEVIATIONS ABOVE
THE MEAN.  THIS---STRONG FRONTAL CONVERGENCE AND VERY FAVORABLE
UPPER DIFFLUENCE IN THE COUPLED JET EXIT/ENTRANCE REGION OVR THE
SOUTHERN PLAINS WILL SUPPORT VERY ACTIVE CONVECTION BEGINNING LATE
AFTERNOON/EVENING AND CONTINUING THROUGH THE REMAINDER OF THE DAY
1 PERIOD.  THERE MAY BE A BREAK IN ACTIVITY BETWEEN CONVECTION
OVERNIGHT INTO TUE MORNING AND THEN A SECOND ROUND LATER TUESDAY
AFTERNOON---BUT OVERALL A VERY ACTIVE PRECIPITATION PERIOD LIKELY
ACROSS PORTIONS OF THE SOUTHERN PLAINS INTO THE MID MS VALLEY
REGION.  WHILE THERE ARE MORE NUMEROUS DIFFERENCES IN QPF DETAILS
ON THE SHORTER FORECAST TIME SCALE AMONG THE LATEST MODELS---THERE
IS BETTER AGREEMENT OVERALL FOR THE DAY 1 PERIOD FOR HEAVY
RAINFALL POTENTIAL FROM NORTHEASTERN TX---ACROSS EASTERN TO
SOUTHEAST OK--CENTRAL TO NORTHERN AR AND INTO CENTRAL TO SOUTHERN
MO---WITH AREAL AVERAGE 1-2"+ AMOUNTS DEPICTED.

NORTHERN PLAINS INTO THE UPPER MS VALLEY/UPPER LAKES AND NORTHERN
NY

THERE IS GOOD AGREEMENT IN THE LATEST MODEL GUIDANCE WITH THE VERY
SLOW EASTWARD PUSH OF THE STRONG CLOSED LOW INITIALLY OVER THE
EASTERN PORTION OF THE NORTHERN PLAINS.  A PERSISTENT COMMA
HEAD/DEFORMATION PRECIPITATION BAND WILL AFFECT THE NORTHERN
PLAINS INTO THE FAR NORTHERN UPPER MS VALLEY WITH A DURATION
MODERATE TO ISOLATED HEAVY PRECIPITATION EVENT.  THE EASTERN
PORTION OF THE ABOVE AREA ACROSS THE UPPER LAKES INTO NORTHERN NY
WILL HAVE A BETTER CHANCE OF CONVECTION DAY 1 AS LOW LEVEL
SOUTHWESTERLY FLOW OVERRUNS THE WEST TO EAST ORIENTED FRONTAL
BOUNDARY DRAPED FROM THE UPPER LAKES INTO NORTHERN NY AND NEW
ENGLAND.  MODERATE TO HEAVY PRECIPITATION AMOUNTS POSSIBLE HERE.

PACIFIC NORTHWEST

HEIGHT FALLS OFF THE WEST COAST OF CANADA WILL DIVE SOUTHWARD DAY
1---AMPLIFYING A CLOSED LOW OFF THE PACIFIC NORTHWEST COAST.
MODEL CONSENSUS IS FOR .25-.50" AMOUNTS AS A STRONG FRONTAL
BOUNDARY BRINGS STRENGTHENING UVVS---HIGHER PW VALUES AND MUCH
COOLER TEMPS INTO THE PAC NW THIS PERIOD.  A COMBINATION OF THE
NAM AND SREF MEAN WERE USED PRIMARILY FOR QPF DETAILS THIS PERIOD.

SOUTHERN MID ATLANTIC SOUTHWARD INTO FLORIDA

AN AXIS OF ABOVE AVERAGE PW VALUES WILL ALSO PERSIST DAY 1 FROM
THE SOUTHERN MID ATLANTIC SOUTHWARD INTO FL. AN UPPER TROF AXIS
ORIENTED NORTH-SOUTH ACROSS THESE AREAS WITH TWO WELL DEFINED
CIRCULATIONS...ONE MOVING ACROSS SOUTHERN VA AND ANOTHER OVER
NORTHEAST FL---WILL KEEP CONVECTIVE PRECIPITATION CHANCES HIGH.
CONFIDENCE IN QPF DETAILS RATHER LOW IN THIS AXIS---BUT HIGHER
OVERALL FOR THE 24 HOURS PERIOD THAT ADDITIONAL MODERATE TO HEAVY
PRECIPITATION AMOUNTS WILL FALL.

ORAVEC

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

24HR QP VT 22/00Z
 0.01 536211 537207 537201 535196 535190 529188 514190 511191
      508190 503188 497186 494184 489182 484181 476183 465182
      456175 454171 452164 452159 449163 448167 446170 443183
      438185 437187 431194 428198 426202 428207 426211 420219
      418221 414223 400235 400241 400245 402251 404253 410254
      413253 422253 427259 432261 435260 439261 444263 446268
      450273 450277 454280 464283 473283 479284 483284 488285
      491285 495284 500285 508283 510281 513281 515276 518273
      520266 524251 525243 527239 531225 533215 536211
 0.01 470707 466693 463689 459683 453669 447656 444652 442650
      440647 433644 430643 428646 423651 422656 417660 416665
      414668 413673 414676 413682 414689 413696 414718 415737
      413759 412764 411768 408770 405778 403783 400783 397784
      394783 390781 386778 385775 380772 378770 378765 378763
      374761 371762 367760 363757 361756 352757 348758 344760
      338765 336768 331770 323775 315775 310777 306777 288781
      269782 253781 245781 240785 237788 235792 234799 239813
      239817 241820 246825 254825 262826 277830 285832 292836
      301835 311836 319838 327835 331834 333832 340826 342822
      346821 354817 358819 363819 368822 372824 376829 377836
      376841 368859 356874 352883 345891 324912 313921 305936
      296951 287965 282972 280982 278992 275996 278000 285003
      293005 300008 305007 335996 340995 345995 351994 357992
      362985 370980 374978 377974 382966 393948 403936 408930
      412934 415935 417940 414949 408954 406958 407962 410965
      413964 421958 429952 436946 439942 445941 445948 443954
      436963 431972 428976 425977 423982 423986 421989 422014
      424022 423031 423044 424056 424060 426067 429071 433073
      438073 441072 444070 447069 450072 455073 459072 467066
      476060 484052 491046 493038 497029 500017 507994 511974
      513962 515955 515946 514936 515931 514914 510877 510870
      509860 506841 500814 497799 493785 489771 484757 479741
      475733 471717 470707
 0.25 513256 515251 516246 515236 513223 510215 507208 499200
      495196 488197 480202 472210 469214 464216 462222 457224
      454220 452218 449217 442217 436217 433221 430226 427232
      423234 416236 414239 416244 423247 435250 439251 446252
      455252 467251 476256 482258 487259 498263 504263 509261
      513256
 0.25 505878 504867 502855 497835 492818 489800 485788 478773
      472759 466744 461729 457714 454708 449702 444699 441699
      438701 434712 432718 430724 429730 430735 429740 430749
      429762 428776 425807 424817 420829 416839 411847 401858
      398861 392865 372880 357894 351901 345909 333927 327936
      321946 317957 313964 309973 308978 307981 309983 313986
      317987 324987 331987 343988 350987 354984 366965 371958
      376950 404912 410906 423899 432893 443888 453884 462889
      464905 463924 462939 460953 452977 451982 451993 454009
      452014 450022 447027 444032 440034 439037 440041 443042
      452044 455043 458038 461032 464027 470026 475022 483013
      491002 494995 497986 498971 499955 501941 503927 504915
      505900 505878
 0.25 359773 358768 357766 353767 349769 339777 332782 324786
      311789 297793 288792 265790 254788 251791 248795 247801
      249807 257816 267821 276824 290822 295821 300818 303812
      304810 307808 320802 326800 327804 331805 334803 341800
      347794 352789 356784 358780 359773
 0.50 506239 508235 508231 506225 504220 501214 497210 492208
      486208 482209 480213 482215 487219 490220 494226 497231
      500235 502241 506239
 0.50 499875 498867 497860 493846 490837 487825 484811 480796
      475784 472773 463755 453739 452732 450725 445722 441727
      437734 436737 435742 435746 436751 439753 440761 440770
      438778 436786 435798 436815 435825 435832 436838 437848
      441855 448859 450861 454866 458873 462877 466879 469882
      474890 478897 479906 481916 483923 485930 489927 491924
      494914 496903 497890 499875
 0.50 488979 488975 487970 486969 485966 483963 480963 477964
      474966 472969 471973 471978 472982 473986 476990 476991
      479991 482990 484988 485988 487984 488983 488979
 0.50 463242 466239 463235 458234 449234 443233 441231 443228
      445224 442223 439223 439226 440231 439235 435237 430239
      427241 424242 427243 436244 444244 456245 463242
 0.50 413890 403876 396879 388882 373887 366891 361895 356900
      351907 347912 343917 328938 324945 321951 318963 314971
      313974 315975 319976 325975 328975 331976 335983 341984
      348984 354980 359973 365962 373949 380939 385932 388925
      395914 399908 405901 409896 413890
 0.50 294801 287799 278798 274797 271794 264793 256794 251799
      255807 259808 262814 266815 272817 279816 283813 284810
      290808 293804 294801
 1.00 474827 475823 474819 472814 468802 465790 461783 458781
      455782 452784 452789 450796 451807 451816 454823 461829
      466831 472834 474827
 1.00 384914 371899 368898 362901 355907 343920 334935 329943
      325950 321960 321964 321969 328967 333966 335970 337974
      338977 340979 348979 351978 355974 359966 368950 380934
      384914
 1.50 375934 372925 370921 366922 363919 364916 365912 364908
      361907 356909 353912 348918 339931 331944 327951 325959
      323962 326963 335962 338963 339969 342976 347977 351975
      355968 363955 367947 372939 375934
 2.00 367936 359931 358924 360919 362912 359911 354915 350919
      344928 340934 338939 335950 334956 337958 341962 342969
      343973 347974 351971 357961 362951 366938 367936
 3.00 353929 350929 348933 347937 346941 347944 347948 345954
      345958 345965 347968 349965 351961 352957 353951 353946
      351943 351938 353932 353929

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