Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 270606
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
205 AM EDT THU APR 27 2017


PRELIM DAY 1 QPF DISCUSSION
VALID APR 27/1200 UTC THRU APR 28/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

...WESTERN U.S...

A STABLE LONG WAVELENGTH TROUGH WITH ITS AXIS THROUGH THE PLAINS
STATES WILL BEGIN TO RELOAD AND DEEPEN WEST OF THAT AXIS TODAY.
MOISTURE IS LIMITED IN AN ABSOLUTE SENSE...WITH PRECIPITABLE WATER
VALUES GENERALLY LESS THAN A HALF INCH...BUT VALUES APPROACHING
0.75 INCHES WILL WRAP NORTH OF THE DEVELOPING LEE CYCLONE...INTO
NORTHERN KANSAS AND SOUTHERN NEBRASKA BY THURSDAY EVENING.
MEANWHILE...STRONG DEEP LAYER LIFT SHOULD MAKE THE MOST OF THE
LIMITED MOISTURE CONTENT ALONG AN AXIS OF DIFLUENT UPPER FLOW
SUPERIMPOSED ON INVERTED SURFACE TROUGHING FROM SOUTHERN MONTANA
THROUGH MUCH OF WYOMING INTO THE CO/NE/KS TRI-STATE AREA. MODELS
TRENDED NORTH JUST SLIGHTLY WITH RESPECT TO KS/NE...AND ALSO
INCREASED AMOUNTS SOMEWHAT. WPC TOOK A CONSENSUS APPROACH AND
INCORPORATED CONTINUITY. OVERALL THERE WAS LITTLE CHANGE FROM THE
PREVIOUS FORECAST. THE HEAVIEST FORECAST AMOUNTS INCLUDE NORTHEAST
WYOMING WITH SOME UPSLOPE ENHANCEMENT...BUT PRIMARILY RELATED TO
THE INVERTED SURFACE TROUGH...AND THEN DOWNSTREAM INTO SOUTHERN
NEBRASKA WHERE THE DIFLUENT UPPER PATTERN IS SUSTAINED AND PIVOTS
WHILE THE LEE CYCLONE FORMS FARTHER SOUTH.

STEEP LAPSE RATES AND CONTINUED ENERGETIC FLOW WILL ALSO MAINTAIN
A SHOWERY REGIME OUT THROUGH THE PACIFIC NORTHWEST...ALTHOUGH WITH
SOMEWHAT LIGHT 24-HOUR ACCUMULATIONS.


...EASTERN U.S...

A SURFACE CYCLONE WILL LIFT THROUGH THE GREAT LAKES INTO ONTARIO
WHILE THE PARENT UPPER TROUGH SWINGS EASTWARD. THIS WILL PUSH A
PLUME OF MOISTURE THROUGH THE EASTERN STATES AND TO THE
COAST...WHILE THE COLD FRONT MAKES MORE PROGRESS INTO THE
NORTHEAST STATES...AND STALLS OVER THE SOUTHEAST. ONE OF THE MORE
PRONOUNCED SIGNALS IS IN THE WRAPAROUND AREA JUST LEFT OF THE LOW
TRACK OVER WISCONSIN AND THE UPPER PENINSULA OF MICHIGAN...WHERE
WE INCREASED AREAL AVERAGE AMOUNTS. OVERALL...HOWEVER...MOISTURE
IS SOMEWHAT MARGINAL...AND INSTABILITY WEAK OVER MUCH OF THE
EASTERN U.S...SUCH THAT VERY FEW STATIONS WILL RECEIVE MORE THAN
AN INCH OF RAIN TODAY. THE MOISTURE PLUME IS FORECAST TO COME
ACROSS THE HIGH TERRAIN OF WEST VIRGINIA DURING PEAK
HEATING...WHICH SHOULD YIELD A BOOST TO CAPE VALUES AND COVERAGE
OF CONVECTIVE RAINFALL. SOME OF THIS MAY SPILL OVER INTO THE
PIEDMONT AREAS EAST OF THE SPINE BEFORE WEAKENING. FARTHER SOUTH A
RELATIVE MAXIMUM SHOULD ALSO OCCUR FROM ALABAMA TO NORTH CAROLINA
IN A RELATIVELY CONCENTRATED SWATH...ALTHOUGH THE TROUGH AND
STRONGER HEIGHT FALLS WILL SWEEP UP THROUGH THE OHIO
VALLEY...LEAVING THE SOUTHEAST STATES WITH MORE WESTERLY FLOW TO
PROMOTE FORWARD PROPAGATION...ALONG WITH LESS INTENSE LIFTING.

MODEL QPF SPREAD WAS MINIMAL. WPC USED OUR IN-HOUSE PSEUDO BIAS
CORRECTED ENSEMBLE...ALONG WITH THE PREVIOUS WPC FORECAST...AND A
SMALL PERCENTAGE OF THE NAM.

BURKE

GRAPHICS AVAILABLE ON THE WEB AT
WWW.WPC.NCEP.NOAA.GOV/QPF/QPF2.SHTML

24HR QP VT 28/12Z
 0.01 538189 537180 535171 532164 528158 511136 506129 505123
      507116 510113 519106 522086 512081 488070 479066 466059
      461052 457047 449034 445024 442016 439009 438002 432987
      428971 418939 414919 414912 411909 406903 396895 392892
      387892 385894 373900 369905 365912 362916 359923 357927
      357931 357941 357958 359977 360987 360999 360005 362007
      366014 378040 386051 382053 379053 374048 364047 357050
      354056 353067 354075 357084 359087 363085 365081 368084
      371089 384095 389091 392090 396090 404091 409088 415092
      419097 419102 417106 412106 405105 398107 392112 388116
      390118 392119 400121 407124 414123 418124 421126 425132
      431132 437136 438140 438151 441159 445164 446171 446174
      442180 437179 433176 431174 430170 423159 424150 423147
      421147 416154 414156 414162 419173 423179 425183 423188
      423191 425193 431195 437202 438204 438207 436211 432220
      429223 425224 422229 425231 429231 433233 434236 438243
      441249 449252 462251 465252 468250 472249 475252 481255
      484259 488262 499267 503268 504263 502255 499249 494243
      490240 493234 496234 500232 502232 504236 510248 514249
      516247 518242 518236 517227 515221 514216 513211 516209
      519207 522208 526209 529207 530203 532198 535192 538189
 0.01 531843 530835 529829 525816 522803 520797 515798 510799
      506801 502797 502789 498775 491766 484760 476754 469751
      467750 467747 466740 462731 455724 450721 445722 434720
      416717 394722 384726 374733 365739 357747 345762 340768
      342772 345771 349769 352770 355775 349782 342790 334798
      328806 323814 318822 311830 305838 299844 296855 296863
      295870 293874 296877 299882 301884 301887 298898 298904
      304903 313886 316882 322880 332875 353868 372863 382861
      388861 394863 416866 418867 417870 417875 411884 409890
      411895 416902 422910 426912 431914 444914 450914 455915
      466916 472917 476919 478923 479932 479940 478948 475955
      478961 482965 487966 492968 496970 500967 506961 510958
      516957 522952 525947 526940 527924 529910 531902 531894
      530886 529881 529875 528867 528859 531843
 0.01 492684 492680 490677 487672 484678 482684 479689 476694
      473700 472703 473706 475708 476706 481703 487699 490695
      492687 492684
 0.01 489193 489190 487187 484184 478180 471173 467170 465170
      464174 464180 463183 458190 455193 453198 452204 455207
      460209 464208 471205 479201 486198 489193
 0.01 453132 452127 451124 449122 446122 444123 441125 440129
      439132 440134 443136 446138 450136 452134 453132
 0.01 404158 402155 400155 402158 404158 404158
 0.01 356193 357189 357185 356182 354181 350180 348181 346182
      345187 344191 345194 346196 350197 352197 354195 356193
 0.25 515161 513153 509149 502139 498135 493130 490126 485127
      476134 475139 477142 477147 481151 483153 482156 481160
      483161 485161 485158 488157 492160 496164 499166 503166
      505161 511162 515161
 0.25 517863 517852 516843 512835 507831 502830 496832 484840
      479842 474847 473851 471855 466858 444872 435880 431886
      430890 430893 436897 442898 455901 462901 469900 475900
      482902 497922 501927 506929 512926 514918 514907 513896
      513884 513877 517863
 0.25 489216 488213 486211 482210 481211 477212 475214 473215
      473217 476217 478217 482217 485219 487218 489216
 0.25 482786 481781 479779 475774 470771 464770 451773 447768
      443762 442757 440755 435756 430762 424765 415772 409777
      403778 398779 393783 386795 377804 377810 378815 381817
      384818 388816 392812 395810 399807 405805 412805 418805
      425803 430798 433792 434789 437788 445790 449792 454796
      460798 467798 471797 475795 479792 482786
 0.25 474096 476089 473083 467076 454061 443043 437037 433033
      430029 426019 423008 421994 418982 413974 407966 405962
      404954 402940 401935 399930 390933 387938 386944 384959
      384971 383978 384983 385992 385001 386013 387026 387031
      389036 393039 399042 406049 406054 404058 398066 398071
      402075 410075 414078 417082 422090 429099 430105 430111
      433115 437114 444108 448105 454104 458102 463102 467104
      470105 471103 474096
 0.25 468152 468150 467149 466148 464148 462148 461151 462152
      464153 465154 467154 468152
 0.25 456221 455221 454219 452219 450218 449219 447218 446218
      445219 443219 442219 441219 440222 440224 441225 442225
      444226 446226 448226 449225 451225 453224 454223 455222
      456221
 0.25 373839 373837 371837 370837 368837 366837 365838 364839
      363840 361841 360842 359844 358846 358848 360848 363847
      366844 368844 370842 372841 373839
 0.25 366809 366795 363790 360790 353795 346803 340809 333815
      327822 322831 312847 311852 310857 311861 311867 314870
      319869 328864 336860 342853 349848 357841 357836 357830
      359824 361819 366809
 0.50 509862 510855 508849 506846 503844 498843 495845 487849
      481853 477861 474869 471872 466872 457874 451877 445883
      444887 446890 453892 463892 472892 482891 487894 491896
      495897 498896 501893 503883 506872 509864 509862
 0.50 501147 500144 498142 497142 495143 494143 494145 495146
      496148 497149 498149 499149 501147
 0.50 461084 459078 456072 449060 445054 441050 436045 430042
      426037 423030 420014 417999 415991 412984 408979 402976
      398977 396979 394986 392994 391003 392012 394020 396028
      399033 412040 416044 419049 421058 419069 422076 424083
      429088 434092 438097 442097 443094 444086 448085 456089
      460088 461084
 0.50 437770 437768 436767 435768 434768 433770 433771 432773
      433775 435773 436773 437771 437770
 0.50 398800 396798 393798 392799 390801 387803 385805 383807
      382809 384811 387810 390808 392807 395805 397802 398800
 0.50 360803 360798 357797 353799 351802 344812 339816 334820
      329825 327831 324838 321843 318848 318856 321858 323857
      329852 332848 336842 344833 349833 350830 351826 352817
      355811 358807 360803
 1.00 452076 451073 450070 448068 446065 444063 442062 438061
      436062 436066 438069 440071 441072 445074 447075 450076
      452076
 1.00 412015 412010 411008 411003 410999 408996 406994 405993
      402993 401998 401002 402007 403009 406012 408013 410014
      412015

$$




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