Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 231850
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
249 PM EDT TUE SEP 23 2014


PRELIM DAY 1 QPF DISCUSSION
VALID SEP 24/0000 UTC THRU SEP 25/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1


PACIFIC NORTHWEST INTO NORTHERN CALIFORNIA

MODELS ARE IN GOOD AGREEMENT WITH THE EVOLUTION OF THE DEEP LOW
CURRENTLY OVER THE NORTHEAST PACIFIC OFF THE PACIFIC NORTHWEST
COAST.  THIS LOW HAS REACHED ITS PEAK INTENSITY AND IS EXPECTED TO
ONLY SLOWLY WEAKEN DAY 1 AS IT REMAINS OFF THE PACIFIC
NORTHWEST/SOUTHWEST CANADIAN COASTS.  THE AXIS OF ABOVE AVERAGE PW
VALUES AND STRENGTHENING SOUTHERLY TO SOUTH SOUTHWESTERLY LOW
LEVEL FLOW ALONG AND AHEAD OF THE ASSOCIATED FRONTAL BOUNDARY
WILL---HOWEVER---PUSH INTO THE PACIFIC NORTHWEST/NORTHERN
CALIFORNIA TONIGHT INTO WEDNESDAY.  THIS WILL SUPPORT LIKELIHOOD
OF WIDESPREAD MODERATE TO HEAVY PRECIPITATION TOTALS FROM THE
PACIFIC NORTHWEST---TO THE WEST OF THE CASCADES--SOUTHWARD INTO
NORTHWEST CALIFORNIA COAST RANGE.  FOR QPF DETAILS THE NAM AND
ECMWF WERE USED---WITH WIDESPREAD 1"+ AMOUNTS DEPICTED.

SOUTHEAST COAST INTO THE COASTAL SOUTHERN MID ATLANTIC

A WET PATTERN TO CONTINUE DAY 1 ALONG THE SOUTHEAST
COAST---SPREADING NORTHWARD INTO THE SOUTHERN MID ATLANTIC COASTS
AS THE CLOSED LOW THAT HAS DEVELOPED OVER THE SOUTHEAST WILL BE
LIFTING SLOWLY NORTHWARD.  STRENGTHENING SOUTHEASTERLY TO EASTERLY
FLOW ALONG AND NORTH OF THE STATIONARY FRONTAL BOUNDARY/INVERTED
TROF FORECAST TO LIE ALONG THE SOUTHEAST/SOUTHERN MID ATLANTIC
COASTS WILL SUPPORT POTENTIAL FOR WIDESPREAD HEAVY PRECIPITATION
TOTALS ACROSS THESE AREAS. THERE IS GENERAL AGREEMENT AMONG THE
LATEST MODELS IN KEEPING THE HEAVIEST TOTALS ALONG AND JUST OFF
THE IMMEDIATE COASTAL SECTIONS FROM EASTERN NC INTO THE SOUTHERN
DELMARVA PENINSULA.  THERE ARE MORE MODELS DIVERGENCES WITH
RESPECT TO HOW FAR INLAND THE WESTERN EDGE OF THE MODERATE TO
HEAVY TOTALS SPREAD.  THE 0000 UTC ECMWF AND 1200 UTC CMC ARE THE
FARTHER INLAND SOLUTIONS--WITH THE HI RES ARW--NMM---NAM CONEST
AND GFS FARTHER TO THE EAST.  AT THE MOMENT--THE DAY 1 QPF LEANED
TOWARD THE TIGHTER GRADIENTS NEAR THE COASTS.  INTENSE RAINFALL
RATES POSSIBLE WITH CONVECTION MOVING NORTHWARD ALONG COASTAL
SECTIONS OF EASTERN NC INTO FAR SOUTHEAST VA---WITH RUNOFF ISSUES
POSSIBLE---ESPECIALLY IN MORE URBANIZED REGIONS.

UPPER MS VALLEY INTO THE CENTRAL TO SOUTHERN PLAINS

THE HEIGHT FALLS THAT MOVED INTO THE CENTRAL TO NORTHERN PLAINS
LAST NIGHT/EARLY TUESDAY WILL CONTINUE TO PRESS NORTHEASTWARD INTO
THE UPPER MS VALLEY TONIGHT/WEDNESDAY WHILE CONTINUING TO WEAKEN.
IN ITS WAKE---A ELONGATED SHEAR AXIS EXPECTED TO STRETCH FROM THE
UPPER MS VALLEY---SOUTH SOUTHWESTWARD INTO THE CENTRAL TO SOUTHERN
PLAINS.  WITH PW VALUES REMAINING ABOVE AVERAGE AND WEAK VORTS
EMBEDDED IN THIS AXIS---WIDESPREAD SCATTERED CONVECTION POSSIBLE
ACROSS THESE AREAS.  CONFIDENCE IS LOW WITH RESPECT TO DETAILS
GIVEN THE OVERALL WEAKENING TREND AND VARIETY OF SOLUTIONS IN THE
LATEST GUIDANCE.  DAY 1 QPF LEANED TOWARD THE IN HOUSE PSEUDO BIAS
CORRECTED MEAN OVERALL FOR DETAILS.  MODERATE AREAL AVERAGE
AMOUNTS DEPICTED WITH POTENTIAL FOR ISOLATED HEAVY TOTALS WHERE
CONVECTION DOES BECOME MORE ORGANIZED.

SOUTH TEXAS

EASTERLY LOW LEVEL FLOW OFF THE WESTERN GULF OF MEXICO IN AN AXIS
OF SLIGHTLY ABOVE AVERAGE PW VALUES WILL SUPPORT PERSISTENT
SHOWERY CONDITIONS OVER SOUTH TEXAS DAY 1.  CONFIDENCE LOW WITH
QPF DETAILS---WITH MODERATE TO ISOLATED HEAVY TOTALS POSSIBLE.

CENTRAL TO SOUTH FLORIDA

WET CONDITIONS TO PERSIST ACROSS CENTRAL TO SOUTH FLORIDA AS AN
AXIS OF HIGH PW VALUES REMAINS IN PLACE IN THE WAKE OF THE WEAK
SURFACE WAVE MOVING NORTHWARD ALONG THE SOUTHEAST/SOUTHERN MID
ATLANTIC COASTS.  ADDITIONAL LOCALLY HEAVY TOTALS POSSIBLE--BUT
WITH MODELS SHOWING A WIDE VARIETY OF SOLUTIONS WITH RESPECT TO
PLACEMENT--CONFIDENCE IS LOW WITH RESPECT TO THESE DETAILS.

ORAVEC

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

24HR QP VT 25/00Z
 0.01 541189 540181 538172 535166 531162 519153 506151 502147
      496143 490142 485145 479148 475154 473156 475159 478165
      480168 482172 477177 468186 457193 447199 427213 423218
      419220 417217 414216 411217 406221 362244 357248 353252
      351262 357264 360267 362267 368263 378259 385256 391260
      404263 417262 424260 430260 444260 458263 465263 472265
      485273 491277 494283 497286 499286 505287 510283 515277
      518273 520270 521264 522252 521244 517230 517224 520224
      526223 531221 537216 539201 540192 541189
 0.01 516895 516879 514876 510877 496887 491888 487890 476891
      470888 465887 459886 454888 449889 442894 437898 431904
      427908 424912 421916 419921 419926 417928 414928 410930
      405930 391940 384945 379950 373956 367963 353976 349983
      344991 340999 333003 325007 322009 318013 316015 316020
      318024 321029 324036 325039 324042 322046 318054 317058
      321059 326059 329058 333057 336054 342048 349039 355034
      363031 368023 372014 379009 382006 382999 378993 382986
      385981 388979 395974 401973 405975 406982 407994 410004
      416011 419013 424013 428003 428996 428990 428986 430983
      433980 435976 438972 442973 445975 448978 458979 461975
      464970 467961 468954 467949 466944 463942 458941 454939
      447935 439931 440928 442928 449928 457932 467933 471935
      476935 481936 484937 492940 495938 498934 503926 506922
      508918 513908 516895
 0.01 393759 393750 392741 388726 382715 370719 358725 349731
      328743 308756 287768 267779 258785 251787 245790 240793
      237797 233807 230819 228832 227839 228846 229855 231860
      237868 243870 249871 259866 262863 266860 279842 285839
      288835 296827 298823 300821 304819 317816 324814 330813
      334815 339817 347816 352813 357811 364809 369807 376806
      384799 390789 392781 393774 393759
 0.01 299105 300097 299091 296079 293073 290069 279065 268058
      260051 253044 249039 245036 239033 235035 233035 231038
      229043 228054 223068 222074 222080 225086 229089 237096
      248101 254101 257097 263099 268103 276109 282112 289112
      295109 299105
 0.01 275976 276972 274970 268970 263966 258964 244962 239965
      237969 235975 235982 236989 238995 242998 247001 258005
      265005 269005 270003 273997 273993 272986 270982 272980
      275976
 0.25 532205 533201 533196 532188 530184 527178 519169 515166
      510163 504161 499163 491169 488172 486179 478189 472197
      464204 459205 455209 448214 437217 429221 425227 421228
      417230 414225 411224 409226 405229 400230 396232 387239
      386244 391247 401253 405256 412258 421257 432255 442254
      453253 463254 469254 476257 484264 492273 496278 500281
      505280 508277 516268 518262 519253 516240 512227 501207
      503201 508198 512199 516203 519207 525210 529209 532205
 0.25 496909 494906 492905 489905 485905 484907 482912 482914
      481919 482924 486924 489922 490920 492917 494914 495911
      496909
 0.25 432952 431947 428942 424940 421940 412941 407942 403945
      397949 394952 398954 405956 412963 416971 419973 423973
      426968 428964 431954 432952
 0.25 387751 387743 385736 380729 376727 370728 363729 359732
      349737 341742 324753 308764 293776 280790 277793 275797
      283802 280804 278803 274800 267795 262794 256794 250796
      246798 241806 239816 239819 241823 243825 248828 252828
      275829 281828 283824 288816 292812 296809 308808 327800
      333800 338797 347792 354788 361787 365789 368792 373793
      381789 384786 385779 386765 387751
 0.25 393959 391957 388958 382959 376961 371963 368967 364974
      364980 366982 369983 375981 380977 384973 387969 391964
      393959
 0.25 368001 368995 366992 365990 361996 355999 347001 341004
      342013 344016 347019 351019 354016 358011 363005 368001
 0.25 280090 279083 276078 267069 259060 249052 244049 238046
      234047 233050 232059 233066 236072 246080 257087 259088
      261087 264086 268086 275088 280090 280090
 0.25 254982 254980 253979 253978 252976 252975 251976 250976
      248977 246977 246978 246980 246981 246982 248983 249984
      250984 251984 253984 254982
 0.50 530199 527189 525185 522181 515175 509169 506166 503166
      496171 494173 493180 494186 497190 507190 510190 513192
      519199 525203 528202 530199
 0.50 515261 516254 515249 513240 510230 506222 498207 494199
      488195 482196 475200 469205 462208 451215 436219 430223
      428228 426232 420233 415231 412228 409229 407232 403231
      399233 396235 394239 394242 396246 400248 407253 411254
      417254 424253 438251 455249 471252 480256 485261 497275
      502277 508269 512266 515261
 0.50 494241 494240 492239 492240 494241 494241
 0.50 384754 383746 382740 379735 374733 363734 353739 344743
      334749 319762 312768 308772 305776 301785 300790 301796
      305799 310800 317799 323797 331792 339786 347780 351777
      357776 363775 368777 371780 374781 377780 382777 384772
      384756 384754
 0.50 270824 266821 262817 258813 256807 254804 252802 248803
      246805 244811 243817 244820 246821 254821 259823 265825
      270824
 0.50 261074 259070 257066 253063 250061 247058 244055 241053
      238055 239060 241064 244066 247069 251072 254074 259075
      261074
 1.00 509251 509245 508237 504227 500217 497212 493208 487205
      481205 473208 466212 461213 456215 448219 439221 435223
      432228 433232 435234 435237 430238 425237 415234 411235
      408239 404238 401242 403244 407244 411247 415251 422251
      427250 431248 440244 450245 460245 470246 474247 479249
      487256 493264 497269 499269 499264 498258 495252 490244
      487242 485243 482245 478233 475232 471235 465233 460233
      451232 467222 470219 475218 484219 488221 491226 496237
      500243 503249 506253 509251
 1.00 381761 381755 380748 379744 376739 371739 366740 358741
      349745 341749 335754 328761 322767 317773 312780 311786
      313791 317792 322791 329787 336782 343776 351771 360768
      363766 368766 375769 378769 380767 381761
 1.50 502236 502231 501227 499224 498222 497219 493220 493225
      494228 495232 496235 498237 501238 502236
 1.50 488216 487213 486212 484211 482211 481210 479211 477211
      475212 477214 478215 480216 482216 483216 485217 487216
      488216
 1.50 462221 463218 461217 460217 459218 457219 456221 457222
      458223 460223 462221 462221
 1.50 429245 429241 428240 424238 421237 418236 415236 414241
      415244 416247 419248 423248 425248 427247 429245
 1.50 379759 378749 375742 370741 366742 357744 349747 343750
      332761 327766 324771 319777 317785 322786 329782 341774
      354767 361763 368761 372760 375762 379759
 2.00 428245 428243 428241 426240 424240 423239 421239 419240
      418242 417244 418246 420246 421246 423247 425246 427245
      428245
 2.00 371754 371748 367746 363745 357746 349749 344752 340755
      336761 330768 328772 332775 340772 349767 356763 364759
      369757 371754
 3.00 359754 358750 354751 351752 348754 346755 344757 342759
      341763 341764 345765 348763 351762 354760 356759 358756
      359754

$$




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