000
FXUS04 KWBC 221855
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
254 PM EDT WED MAY 22 2013


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



DAY 1

EASTERN U.S. FROM THE APPALACHIANS THROUGH THE SOUTHEAST---MID
ATLANTIC---NY STATE INTO NEW ENGLAND

AN AXIS OF MUCH ABOVE AVERAGE PW VALUES WL STRETCH ACROSS A LARGE
PORTION OF THE EASTERN SEABOARD FROM THE SOUTHERN TO CENTRAL
APPALACHIANS---THROUGH THE SOUTHEAST--MID ATLANTIC AND INTO NEW
YORK STATE AND NEW ENGLAND.  THIS WILL SUPPORT POTENTIAL FOR
WIDESPREAD MODERATE TO HEAVY PRECIPITATION AMOUNTS ACROSS THESE
AREAS THIS PERIOD AHEAD OF THE EASTWARD PUSH OF A FAIRLY AMPLIFIED
UPPER TROF MOVING IN PIECES FROM THE UPPER MS VALLEY/GREAT LAKES
REGION INTO THE OH VALLEY.  FAVORABLE RIGHT ENTRANCE REGION JET
DYNAMICS AND WELL DEFINED BOUNDARY LAYER CONVERGENCE IN THE ABOVE
MENTIONED ANOMALOUS PW AXIS WILL SUPPORT THE WIDESPREAD MODERATE
TO HEAVY PRECIPITATION THREAT.  THERE ARE A LOT OF MODEL QPF
DETAIL DIFFERENCES ACROSS THESE AREAS---LEADING TO LOW CONFIDENCE
WITH SHORT TERM DETAILS.  HOWEVER---WITH THE ABOVE MENTIONED
OVERALL FAVORABLE LARGE SCALE PATTERN---CONFIDENCE IS HIGHER FOR
THE WIDESPREAD PRECIPITATION THREAT.  AREAL AVERAGE .25-.50"+
AMOUNTS DEPICTED ACROSS THESE AREAS---WITH LIKELIHOOD OF LOCALLY
HEAVIER TOTALS.

FL

THE UPPER LOW THAT HAS BEEN OVER NORTHERN FLORIDA THE PAST FEW
DAYS WILL BE DRIFTING OFFSHORE OF THE NORTHEAST COAST LATE THIS
AFTERNOON.  THIS WILL BE LEADING TO A SHIFTING OF THE LOW LEVEL
FLOW TO OFFSHORE ALONG THE EAST COAST OF FLORIDA.  THIS WILL BRING
AN END TO THE LOCALIZED VERY HEAVY RAINFALL AMOUNTS THAT HAVE
AFFECTED THE SOUTHEAST COASTAL SECTIONS OVER THE PAST FEW DAYS IN
THE LOW LEVEL SOUTHEASTERLY FLOW.

PACIFIC NORTHWEST INTO THE NORTHERN ROCKIES

LATEST MODEL GUIDANCE IS SHOWING FAIRLY GOOD AGREEMENT WITH THE
EVOLUTION OF THE STRONG PACIFIC NORTHWEST CLOSED LOW---SHOWING
LITTLE MOVEMENT TO THE EAST OVER THE NEXT 24 HOURS AS VORTS ROTATE
AROUND THE MEAN CENTER.  MODEL QPF DISTRIBUTIONS ARE ALSO IN GOOD
AGREEMENT---SHOWING ONE MAX ALONG COASTAL SECTIONS OF WA/OR FROM
THE OLYMPICS SOUTHWARD ALONG THE COAST RANGE WHERE ONSHORE
WESTERLY---BACKING TO SOUTHWESTERLY TO SOUTHERLY LOW LEVEL FLOW
WILL PERSIST.  THIS WILL SUPPORT MODERATE TO HEAVY PRECIPITATION
AMOUNTS IN THE .50-1"+ AREAL AVERAGE RANGE.  THE OTHER
PRECIPITATION MAX WILL BE FARTHER INLAND IN THE UPSLOPE REGIONS OF
THE NORTHERN ROCKIES FROM FAR NORTHWESTERN WY---THROUGH WESTERN
MT.  HEAVY PRECIPITATION AMOUNTS POSSIBLE HERE WITH AREAL AVERAGE
AMOUNTS IN THE .50-1.5"+ RANGE DEPICTED.  IN BOTH PRECIPITATION
REGIONS---THE NAM AND SREF MEAN WERE USED MORE THAN OTHER GUIDANCE
GIVEN THEIR HIGHER RESOLUTIONS.

SOUTHERN PLAINS...

BY THE END OF THE DAY 1 TIME PERIOD---THURSDAY
AFTERNOON---CONVECTION MAY BECOME MORE ACTIVE ALONG AND NORTH OF
STRENGTHENING FRONTAL BOUNDARY EXPECTED TO BECOME STATIONARY AND
ORIENTED FROM IN THE LEE OF THE CENTRAL ROCKIES---EAST
SOUTHEASTWARD ACROSS NORTHERN TX.  CONFIDENCE LOW GIVEN THE BIG
SPREAD IN THE OPERATIONAL---HI RES AND SREF GUIDANCE QPF.  THE
SREF MEAN AND IN HOUSE PSEUDO BIAS CORRECTED MEAN USED GIVEN THESE
UNCERTAINTIES---DEPICTING MODERATE AREAL AVERAGE AMOUNTS IN THE
.10-.25" RANGE WITH POTENTIAL FOR LOCALLY HEAVIER TOTALS.


ORAVEC

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

24HR QP VT 24/00Z
 0.01 500635 497632 494634 490635 480639 474643 470648 463662
      459671 452677 448679 444675 439674 432678 426685 422692
      417699 405718 393725 382733 380736 376738 367743 361745
      355745 349744 341745 335747 327752 322761 318766 312769
      308769 300772 296772 290774 284774 276776 261780 243798
      241802 243805 249806 254804 260802 263801 266801 271801
      277804 282802 286801 290803 283807 278812 277817 282820
      287823 293824 303825 311823 314819 328813 331813 327817
      324820 320823 316825 314828 311830 310833 309842 305853
      300864 293871 289876 286879 281884 278889 280896 283899
      291900 296899 301894 302892 307891 317893 323891 326888
      331886 337879 342874 348871 365855 374846 383838 386840
      386845 385853 387864 389871 395870 400871 407869 410869
      410873 406879 406884 407893 408897 407902 400913 401921
      406925 411929 419929 423929 428928 435929 441928 448926
      452921 456919 458916 461908 462902 464896 466888 467884
      467879 470869 473852 477834 479827 484819 489806 490798
      492790 496775 498768 499760 503740 507720 507709 506698
      507691 506682 508672 505659 504652 501643 500635
 0.01 534195 535185 534174 533170 533163 533157 532153 526126
      523115 520108 515103 509098 501097 496094 487092 485089
      481089 469088 459086 451086 442085 434086 429089 427087
      424087 426094 427097 426103 423108 427115 433119 436126
      436132 437134 439141 441142 446149 449151 453149 456148
      459145 467148 472153 476159 479166 482174 484178 484185
      483192 479196 476199 472200 460205 455209 453209 451205
      450203 452194 453187 456185 462178 459177 455180 452177
      451171 451176 450179 448182 443183 440186 440192 439198
      443201 444204 445209 438214 428220 425223 425227 430233
      427244 426247 427250 429253 434257 441262 445267 450270
      451273 459277 463282 472286 476287 479286 490290 497288
      500275 504269 509263 517245 519238 518233 519215 521212
      525213 527213 530210 534195
 0.01 381992 380984 376977 371969 366961 359949 355944 349940
      343937 338940 333943 331947 330950 330954 333960 335970
      337973 336975 334974 333974 331977 331981 336987 334990
      330993 324998 314006 309010 305013 303015 296027 295034
      299040 307040 312037 320034 327032 330030 335031 340032
      355038 363037 367033 371025 371015 369008 368997 381992
 0.01 302800 299799 296800 295803 297803 300802 302800
 0.25 498674 496667 493662 490659 485659 481662 478666 470676
      462686 457692 450697 440701 435705 432711 428715 419721
      415730 410735 405738 397746 394749 391749 385752 379756
      374757 365751 357751 347754 343757 338760 334768 327776
      324780 324784 326786 331787 337787 339792 342796 348796
      351797 353799 353805 353810 350814 342820 339823 334827
      323833 319838 317842 316847 317851 320854 322856 326857
      331857 335858 339859 342862 347862 352858 359851 368841
      374834 378830 381824 382821 381817 380817 373820 371818
      371815 373812 381805 403788 414780 420778 424778 431783
      433785 434790 434794 430798 425799 419802 415807 411812
      409815 405815 401816 399819 399826 401832 406832 411826
      414822 418820 424820 427822 431829 431836 431842 430854
      430863 432871 434881 434888 434903 434906 437908 441909
      445907 449903 451898 453891 454881 457869 461855 466841
      474818 480797 486776 490761 494745 498721 499708 500698
      498674
 0.25 524193 526183 525173 525165 523154 521143 519133 516128
      512123 509119 505113 499109 493110 487110 480107 476105
      467099 456095 447092 443095 441100 449124 452128 455131
      462135 466136 474143 480146 483151 487165 492177 497186
      501192 504195 508197 512194 516194 519196 523195 524193
 0.25 504248 506245 507241 505235 499223 495225 494231 495240
      486237 480229 475226 473224 473221 477217 478213 476211
      471209 468210 458214 452218 446228 440234 436238 435241
      435245 437248 442251 449252 454252 463253 473254 483258
      492264 497266 500262 501252 504248
 0.25 397809 395809 392810 392811 393812 395811 397809
 0.25 361980 360973 358970 355965 352961 348958 345957 343962
      345969 347972 351977 354981 354982 354985 357984 361980
 0.25 355992 355990 352991 351992 352993 355992 355992
 0.25 310814 309813 306812 302811 299810 296811 294811 292815
      292818 293819 296819 296820 299820 302820 305819 307818
      309815 310814
 0.50 493678 490670 486669 474679 469684 464690 453705 447710
      443710 440713 432723 418733 413738 405744 400749 397755
      391758 384761 378765 371767 364769 356773 347781 346787
      348790 351791 356791 359792 360794 357800 360804 363805
      367806 374803 384795 388789 393784 398779 406774 412772
      417771 421772 428770 433771 438777 447773 449776 450781
      450787 452797 452805 451812 446825 443832 441842 441847
      443854 444857 446857 450854 462824 466812 472800 479783
      483768 490740 492724 494703 494692 493678
 0.50 520182 520173 520164 520157 518148 514139 508128 506123
      503121 496121 490119 482115 477114 470111 464106 456101
      451100 449100 449104 452109 455118 457123 463125 466127
      469132 472137 477140 482142 484146 487152 489157 492168
      494173 498177 515185 520182
 0.50 476242 476238 473234 467231 465227 466222 462217 457218
      457223 457228 454231 449233 443236 440240 441245 445247
      450248 456247 465247 471246 476242
 0.50 359758 357757 354758 351758 349760 346761 341764 339768
      337772 334775 333779 336778 342776 347773 349770 352766
      355762 359758
 0.50 361821 360818 358817 352818 347820 342825 335830 325836
      321844 322851 333850 340855 343857 345856 348852 351849
      355842 358837 359832 359826 361821
 1.00 479700 477695 474693 471694 469697 467701 455719 450726
      443733 439741 435750 435760 437764 443763 450762 457763
      460766 464767 471759 473754 474748 473742 471740 463744
      457746 456742 457734 461729 467726 472720 477709 479700
 1.00 512156 511147 507139 504136 501136 497135 492132 487126
      478126 475127 475132 480136 486140 491148 494153 499162
      502164 504167 508165 510161 512156
 1.00 384775 382776 379777 377779 377780 374782 373785 376787
      379785 381782 383780 384775
 1.00 354835 355831 354828 352825 351824 348825 345826 343829
      341832 340833 341837 342840 343841 346842 347842 350842
      352840 352839 354836 354835
 1.50 506151 506147 506146 503144 500142 498142 495143 493144
      494145 496149 497150 500153 503153 506152 506151
 1.50 352832 351829 349828 346829 344831 343832 344834 346835
      348836 351836 352832

$$