Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 181859
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
258 PM EDT THU MAY 18 2017


PRELIM DAY 1 QPF DISCUSSION
VALID MAY 19/0000 UTC THRU MAY 20/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


CENTRAL ROCKIES INTO THE CENTRAL HIGH PLAINS

THERE CONTINUES TO BE GOOD MASS FIELD AGREEMENT DAY 1 WITH THE
SLOW EASTWARD MOVEMENT OF THE STRONG CLOSED LOW FROM THE CENTRAL
GREAT BASIN INTO THE CENTRAL ROCKIES...AS THE LATEST SREF AND GEFS
DEPICT 500 MB HEIGHT ANOMALIES AROUND 2.5 STANDARD DEVIATIONS
ABOVE NORMAL. WIDESPREAD HEAVY PRECIPITATION IS AGAIN EXPECTED
N-NE OF THIS STRONG CLOSED LOW FROM CENTRAL TO SOUTHEAST WY INTO
CENTRAL TO NORTHEAST COLORADO...AND ESPECIALLY ACROSS PORTIONS OF
THE SOUTHERN-CENTRAL PLAINS -- ESPECIALLY FROM CENTRAL-NORTHERN
OK...EASTERN KS...AND WESTERN MO. OVER THE PLAINS...THE RISK FOR
HEAVY...POTENTIALLY EXCESSIVE RAINFALL WILL INCREASE SUBSTANTIALLY
AFTER 22-00Z THIS EVENING WITH THE COMBINATION OF FAVORABLE
THERMODYNAMICS AND ROBUST DYNAMICAL FORCING. SPECIFICALLY...WITH
THE SOUTHERLY LOW LEVEL JET INCREASING TO 40-50+ KNOTS BY EVENING
WHILE DEEP LAYER INSTABILITY REMAINS STRONG (MIXED-LAYER CAPES
3000-4000 J/KG).
IN ADDITION...ANOTHER ROUND OF ENHANCED UPPER LEVEL FORCING IS
EXPECTED ACROSS/NEAR THE SAME AREAS IN THE CENTRAL-SOUTHERN PLAINS
ONCE AGAIN FRI AFTERNOON -- AS THE UPPER LEVEL JET STREAK ROUNDS
THE BASE OF THE TROUGH (INCREASING THE UPPER DIVERGENCE/DIFFLUENCE
DOWNSTREAM).

WHILE THE MODELS REMAIN RELATIVELY WELL CLUSTERED WITH RESPECT TO
THE MASS FIELDS (TIMING/STRENGTH)...THE MODEL QPFS CONTINUE TO
SHOW QUITE A BIT OF SPREAD WITH THE QPF DETAILS. GIVEN THE STRONG
CONVECTIVE CONTRIBUTION (I.E. SOME OF THE HIGH RES CAMS SHOW A
MINIMA OF QPF IN AREAS WHERE OTHER CAMS INDICATE A MAXIMA...AND
VICE-VERSA). WPC CONTINUED TO FOLLOW A MORE PRUDENT APPROACH
BEYOND THE NEAR TERM (06-12 HOURS...I.E. WHERE THE HRRR/RAP TRENDS
ARE MORE USEFUL).

SOUTHERN TO CENTRAL PLAINS INTO THE LOWER MO VALLEY

A SURFACE FRONTAL BOUNDARY EXPECTED TO REMAIN NEARLY STATIONARY
DAY 1 FROM PORTIONS OF THE SOUTHERN PLAINS---NORTHEASTWARD INTO
EASTERN PORTIONS OF THE CENTRAL PLAINS---LOWER MO VALLEY INTO THE
MID MS VALLEY TO THE EAST NORTHEAST OF THE SLOW MOVING UPSTREAM
CLOSED LOW.  CONVECTION SHOULD BECOME INCREASINGLY ACTIVE LATE
THURSDAY AFTERNOON INTO THURSDAY NIGHT/EARLY FRIDAY AS THE LOW
LEVEL SOUTH SOUTHWESTERLY FLOW STRENGTHENS INTO THIS BOUNDARY IN A
REGION OF WELL DEFINED UPPER DIFFLUENCE TO THE EAST OF THE GREAT
BASIN/CENTRAL ROCKIES CLOSED LOW.  THE 0000 UTC RUN OF THE ARW AND
NSSL WRF ARE SHOWING A FARTHER SOUTHEASTWARD AXIS OF HEAVY PRECIP
INTO SOUTH CENTRAL TO SOUTHEAST OK AND NORTHWEST AR THAN MOST OF
THE OTHER GUIDANCE---AS THEY DEVELOP MORE OF A COLD POOL WITH THIS
ORGANIZING CONVECTION AND PUSH IT MORE RAPIDLY SOUTHEASTWARD.
WHILE THIS TYPE OF SOLUTION IS POSSIBLE---THE DAY 1 QPF AT THE
MOMENT LEANED AWAY FROM THIS SOLUTION WHICH WERE SIGNIFICANT
CONTINUITY CHANGES FROM THEIR RESPECTIVE PREVIOUS RUNS---FOCUSING
PRECIP CLOSER TO THE NEARLY STATIONARY WEST SOUTHWEST TO EAST
NORTHEASTERLY ORIENTED FRONTAL BOUNDARY.  THERE MAY BE A PERIOD OF
TRAINING OF CELLS PARALLEL TO THE FRONT IN THE 0000-1200 UTC TIME
FRAME--CONTINUING THE THREAT OF ISOLATED RUNOFF ISSUES ACROSS
PORTIONS OF THE SOUTHERN TO CENTRAL PLAINS.

UPPER LAKES---EASTERN LAKES---NORTHERN  NY STATE INTO NORTHERN
NEW ENGLAND

AHEAD OF THE STRONG GREAT BASIN/CENTRAL ROCKIES CLOSED LOW---A
LEAD CLOSED LOW WILL CONTINUE TO WEAKEN  AS IT PUSHES FROM THE
UPPER LAKES EARLY DAY 1 INTO SOUTHEAST CANADA THURSDAY NIGHT/EARLY
FRIDAY.  THE TRACK OF THIS UPPER CENTER AND THE ASSOCIATED SURFACE
LOW SHOULD KEEP THE HEAVIEST PRECIP TO THE NORTH OF THE
U.S./CANADIAN BORDER ACROSS PORTIONS OF SOUTHEAST ONTARIO INTO
SOUTHERN QB.  THE TRAILING FRONT FROM THIS LOW WILL SWEEP THROUGH
THE LOWER LAKES INTO THE NORTHEAST---SUPPORTING AT LEAST AREAL
AVERAGE MODERATE TOTALS FROM NORTHERN NEW ENGLAND INTO NORTHERN NY
STATE AND THE EASTERN GREAT LAKES---WITH ISOLATED HEAVY TOTALS
POSSIBLE WHERE CONVECTION MAXIMIZES THURSDAY EVENING.  THE COMMA
HEAD/DEFORMATION PRECIP BAND EARLY DAY 1 MAY LINGER OVER THE UPPER
LAKES---SUPPORTING MODERATE PRECIP TOTALS FROM FAR NORTHERN WI
INTO THE U.P. OF MI.

HURLEY/ORAVEC


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


24HR QP VT 20/00Z
 0.01 524260 522256 519252 517251 512251 509254 506255 503258
      500261 501267 503272 504276 506281 509283 511285 514285
      516285
 0.01 534217 535208 534201 532196 529193 526190 523184 518176
      501166 498163 495158 490157 487158 477153 469152 463153
      461158 463162 466165 471166 474167 477169 480178 483183
      487187 490189 495190 505191 510199 514210 520217 526225
      531220 534217
 0.01 500619 497620 494622 486627 481629 478625 476623 473628
      468637 463640 460643 454651 453658 453665 455668 460667
      462671 461673 461680 460686 458689 452696 440709 437714
      435724 419728 416738 413751 414756 413763 411776 406784
      403788 400789 398787 397775 399765 402746 398735 391734
      384749 367757 365767 365775 364780 358802 357809 354813
      350822 341838 339841 334843 325844 317848 316852 319853
      324853 327855 331862 337867 344871 348875 348879 347891
      340893 336893 333891 329888 326885 321877 319872 316869
      310863 308864 308871 309882 311887 309891 307895 307900
      299905 297911 300918 303920 304925 307933 314939 318941
      325942 326945 324947 320950 314955 304975 299979 294984
      288990 284993 284997 284002 289005 294010 303010 309014
      309028 312032 314030 321024 328018 335011 354008 358006
      362007 362013 361020 354039 352044 352050 352060 356078
      357080 361081 369077 376085 381086 386086 390083 394087
      392092 392098 398106 398110 395112 389113 383117 381121
      383122 386123 389120 395115 398111 398108 400106 398097
      399091 403092 406102 405113 404117 403124 404126 406128
      411129 416129 421129 428120 427115 423111 419109 417105
      415098 415093 418090 421091 424094 425098 425104 427105
      436100 439099 444099 447099 447094 442088 439083 441078
      449080 450076 450072 448066 449060 453049 455022 455005
      453989 452976 451970 451961 451947 451933 450923 446916
      441908 436902 434892 431882 428876 426872 422862 417858
      415858 415854 418844 421832 425823 431808 434799 439791
      445785 449783 454782 456782 458784 459791 462802 464809
      469809 473810 478810
 0.01 478810 481810 482807 484801 487786 491772 494759 497743
      500729 501726 501720 501713 500708 501703 503697 507683
      509676 509669 509664 511661 513655 513651
 0.01 491137 490132 488128 483127 480124 475123 470122 468125
      469130 471134 474136 477135 482136 485139 489139 491137
 0.01 423699 423692 420687 417685 414687 411691 411697 410702
      412706 414711 418713 421710 423706 423699 423699
 0.01 359918 360916 360914 360912 359910 357910 355910 353910
      351910 350910 348912 348914 348917 348919 350921 352922
      353922 355921 355920 357920 359918 359918
 0.01 295826 292819 287814 281811 278810 276805 272799 267796
      260794 253796 247801 242805 240808 239812 238820 242835
      252835 259836 273839 279835 288833 292829 295826
 0.01 254818 254816 253814 251815 250816 249818 250819 252818
      253818 254818
 0.25 501648 501643 499638 495634 490635 487637 481641 476646
      473655 468683 465697 463708 460724 459729 459739 461748
      462758 463762 464764 470763 480756 483752 486747 488740
      489732 490726 493720 495715 496707 498693 499677 501664
      500654 501648
 0.25 446043 444016 444997 443980 442963 440948 438937 436926
      426903 422890 420884 417882 414883 411884 408882 405880
      401879 398881 395878 394871 394856 395843 393827 392817
      392809 393802 393797 389797 386799 383802 375809 361819
      357822 355826 352832 352838 356848 360854 364857 367861
      369867 370881 370891 373895 374902 371913 366925 363931
      359931 355929 349930 325958 323963 325967 330965 334962
      342956 345956 346960 344966 334984 328988 326984 321983
      313987 308990 306995 307001 310006 314007 318005 320006
      316014 313019 315021 317020 324014 329007 335999 339995
      345995 352995 358996 370999 375001 378005 377011 374017
      371025 369037 368044 366048 360049 359053 358057 359059
      367061 376055 381051 381047 380041 383037 386041 387045
      385051 388056 389061 389065 392068 398069 408068 419073
      426079 429077 432073 436069 438063 441055 446043
 0.25 422803 422802 420802 419804 419806 419808 419809 418811
      418813 418816 420817 420815 421813 422811 422808 422806
      422805 422803
 0.25 261805 261803 259802 257803 256803 256804 254805 254806
      256806 258806 260806 261805
 0.50 497657 494648 491646 487646 484650 485658 485669 483677
      475681 472685 471690 469699 467719 466732 466737 468744
      470747 474745 478738 480729 485721 490714 492705 495694
      495684 496663 497657
 0.50 442038 437029 435024 433017 434012 435004 437000 438992
      437981 436974 436965 435951 432940 430935 427931 424925
      424918 423911 421906 417903 412904 406903 404899 401893
      396890 379886 378891 378895 379904 378910 370929 366939
      360949 354969 351972 346975 344979 343983 344987 347989
      352990 362992 368993 374993 381994 385997 387008 388012
      391018 393046 393053 395057 398060 403061 409062 414064
      417064 419063 422060 427060 430058 434053 436047 438042
      442038
 0.50 376848 377841 376835 375828 374823 370824 368829 366832
      364838 364843 365847 369851 372853 376849 376848
 0.50 352936 352935 352934 350933 348933 347934 346935 345936
      345937 343939 343941 345943 346943 348942 350941 351938
      352937 352936
 0.50 320997 322994 322992 321991 319992 318992 317993 315994
      313995 312996 312998 312000 313002 315002 317002 318001
      319999 320997 320997
 1.00 425049 425044 422042 417042 415040 411033 407027 405030
      406033 406040 401045 399048 399052 404056 408057 411056
      418053 425051 425049
 1.00 427975 426973 426972 425973 424975 426977 427975
 1.00 426961 427959 426956 426955 426954 424952 423954 423956
      424959 426961 426961
 1.00 405986 406979 405972 404961 403939 402933 400929 394922
      389915 384918 380922 378926 375936 374941 371944 366951
      362960 362967 359977 359981 362984 370988 378988 384987
      390987 396991 400993 403991 405986
 1.50 400972 400964 398958 396940 394935 390931 385932 382937
      376947 372952 370956 370960 372961 370967 367972 366976
      368979 373982 380982 386980 393980 398977 400972
 2.00 395970 395963 394959 391955 388954 387956 384961 382964
      379966 375968 372972 373976 378977 382975 386974 391972
      394970 395970
 2.00 391947 391945 391943 391942 389940 388941 386942 386943
      384945 383947 382949 384951 386950 388951 389951 390949
      391947 391947

$$





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