Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 100916
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
416 AM EST SUN DEC 10 2017


FINAL DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION
VALID DEC 10/1200 UTC THRU DEC 13/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

06Z UPDATE...
NO CHANGES WERE MADE TO PRELIM GUIDANCE.

GT LAKES/UPPER MS VALLEY

BEHIND EXITING COASTAL LOW IN THE NORTHEAST THE ONLY PCPN OF ANY
CONSEQUENCE WILL BE SOME LAKE EFFECT SNOWS AND LIGHT SYNOPTIC
SNOWS ASSOCD WITH A QUICK MOVING CLIPPER SYSTEM DROPPING SEWD ACRS
THE EXTREME NRN PLAINS AND UPPER MS VALLEY SUN NIGHT. OVER THE ERN
GT LAKES..FAVORABLE ALONG LAKE TRAJECTORIES WILL DVLP TO THE LEE
OF LAKES ONTARIO AND ERIE ON SUN/SUN NIGHT AHEAD OF A WEAK COLD
FRONT PUSHING EWD INTO THE ERN GT LAKES REGION SUN NIGHT.  THIS
WILL LIKELY LEAD TO MDTLY STG SINGLE BANDED PLUMES OVER THE NE END
OF LAKE ERIE AND ERN END OF LAKE ONTARIO.  A CONSENSUS OF HI RES
MODEL RUNS AS USED HERE GIVEN THE HI MESOSCALE NATURE OF THE
BANDS.  ACRS THE UPPER MS VALLEY/NRN PLAINS REGION...THE GFS STILL
REMAINS A LITTLE FASTER AND FLATTER WITH CLIPPER S/WV DROPPING
SEWD THROUGH THE NRN PLAINS/UPPER MS VALLEY REGION THOUGH ITS QPF
IS NOT THAT MUCH OUT OF LINE WITH A GENL MODEL COMPROMISE AS LIGHT
PCPN BAND IS MORE TIED TO THE TRACK OF ASSOCD WEAK SFC LOW WHICH
IS EXPECTED TO MOVE SEWD ACRS NORTHEAST ND TOWARD CNTL MN BY MON
MRNG.  CHANGES TO CONTINUITY WERE RELATIVELY MINOR..MAINLY SLOWING
THE SEWD ADVANCEMENT OF LIGHT WAA SNOWS AHEAD OF THE SFC LOW AND
ASSOCD WARM FRONT.  FOR MORE DETAILS ON WINTER WEATHER...SEE
QPFHSD.



DAYS 2/3...

...NORTHERN PLAINS/UPPER MISSISSIPPI VALLEY TO THE GREAT
LAKES/NORTHEAST...

TWO WAVES OF LOW PRESSURE WILL SWING ACROSS THE NORTH-CENTRAL AND
THE EASTERN PORTION OF THE CONUS IN THE DAY 2/3 TIMEFRAME. THE
FIRST IS A SHORTWAVE THAT MOVES ALONG THE EXISTING UPPER TROUGH
FROM THE EASTERN GREAT LAKES MONDAY MORNING AND OUT TO SEA BY
MONDAY AFTERNOON.  THE SECOND WAVE IS A STRONGER SHORTWAVE THAT
AMPLIFIES THE UPPER TROUGH AS IT DIGS FROM SOUTH DAKOTA/MINNESOTA
ON MONDAY...CROSSES THE MIDWEST LATE MONDAY...AND REACHES MAINE BY
LATE TUESDAY.

00Z NUMERICAL GUIDANCE WAS IN GENERALLY GOOD AGREEMENT WITH THE
GUIDANCE FROM 09/12Z AND 09/18Z IN TERMS OF QPF.  LOOKING AT LOW
LEVEL WINDS AND H85 TEMPS...FELT THAT THE QPF TO THE LEE OF THE
GREAT LAKES WAS TOO LIGHT GIVEN SUCH LARGE DEL T VALUES.  IN THIS
AREA...THE WPC QPF WAS ABOVE MUCH OF THE GUIDANCE.

THERE WAS SOME MODEL QPF DIFFERENCES OVER THE UPSTATE NY/NORTHERN
NEW ENGLAND.  THE 10/00Z RUN OF THE GFS SLOWED DOWN A BIT IN THE
FIRST HALF OF THE NEW DAY 2 FORECAST PERIOD AND WAS INCORPORATED
ALONG WITH THE ECMWF.  BY DAY 3...THE GFS SPED UP AND WAS GIVEN
DECREASING WEIGHTING ON DAY 3.  THE 10/00Z NAM WAS IN BETTER
AGREEMENT WITH THE ECMWF/UKMET IN TERMS OF PLACEMENT BUT ITS QPF
SOLN APPEARED TO BECOME TOO HEAVY OVER TOO BROAD OF AN AREA.  THE
WPC QPF WAS WEIGHTED MOST HEAVILY TOWARDS THE LATEST ECMWF AND
THEN INCLUDED VARYING WEIGHTING OF THE UKMET AND NAM/GFS.

SULLIVAN/BANN


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

24HR QP VT 11/12Z
 0.01 545041 546030 545025 545019 542009 539003 531988 525972
      520962 515954 504944 501935 501928 499924 492909 488903
      485899 483898 478892 475892 472888 478884 478880 476874
      479867 475862 464833 464825 465819 464809 463802 462796
      463790 466787 471771 472761 471756 469752 469746 467744
      465740 465734 466722 473725 479726 486725 490721 491718
      494709 493702 496703 500701 500697 497687 492677 489669
      491661 490654 488651 484641 482639 478639 475638 471638
      467641 465644 460649 455656 450662 445668 442669 440672
      433677 424684 419689 418693 422694 428695 433694 435692
      439685 440682 445679 449679 452681 458685 460686 463689
      459694 438717 440719 445721 445724 443726 439727 435726
      432728 429728 427731 431733 436732 441733 439737 435738
      431740 424754 425760 425763 423765 420766 419769 417774
      415778 410783 397789 389793 382799 377806 369812 366816
      368818 370816 378812 385809 391805 397800 399797 403795
      407794 409796 410816 412819 415819 419816 422816 427815
      430819 433823 436824 437829 440830 441828 443831 443839
      441846 437849 431830 428832 428837 425848 418858 416861
      417865 421866 426866 431864 441864 444866 448865 461873
      464881 464885 459885 447881 442880 439880 430880 427881
      425883 425894 426907 427911 428916 435928 445942 450950
      453957 457967 459971 462974 467979 469981 470987 473009
      475014 476019 478023 483030 489035 502047 514059 517059
      519057 521053 524053 533054 539051 544046 545041
 0.01 518268 519262 518259 514253 507251 506261 503262 499258
      497257 495254 494257 495262 496266 497271 501277 505281
      509275 514272 518268
 0.01 457751 453748 450751 447754 444758 443764 442769 441774
      442777 444776 447773 448768 450765 453760 454757 457751
 0.01 415698 413687 411685 407686 401690 396696 391701 387707
      386711 387717 389719 392718 394715 398713 405712 409712
      412709 414701 415698
 0.01 412746 411744 409746 408747 407747 406749 406750 405752
      404755 405757 405759 406760 406759 407757 409756 409754
      410752 410751 411749 412746
 0.25 524015 524010 521006 518002 515999 512997 508996 510998
      513001 515004 518008 521012 522015 524015
 0.25 466866 466863 466861 465860 465861 465863 465866 466867
      466866
 0.25 450804 450799 448799 446800 445803 443805 440808 439811
      440815 442816 446815 447812 449810 450806 450804
 0.25 441757 441752 440748 438747 436749 434751 433756 434759
      434762 435766 436768 438766 439764 440760 441757
 0.25 428788 428783 425782 424785 423789 422792 421794 420798
      419801 420804 423803 424801 425798 427795 428791 428788
 0.50 438760 438758 438755 437753 436756 436758 437760 437761
      438760
 0.50 426789 426786 425789 426791 426789
 0.50 425793 426791 424791 424794 425795 425793

24HR QP VT 12/12Z
 0.01 501282 503276 502270 499262 494256 492252 494248 491244
      488242 483241 480242 464242 460242 458245 452251 446254
      440258 441263 443267 450267 463264 477259 481262 483265
      486274 488279 490282 494284 499285 501282
 0.01 517046 515038 511032 504024 490005 484994 482989 479985
      474972 469957 466939 466919 467912 470910 475914 475920
      477927 481934 486929 488926 489922 489916 490914 490909
      492904 493896 495890 499882 500880 499874 499865 499857
      497854 497849 494835 492832 490827 490814 489804 487800
      481788 479780 478772 478761 479752 476739 469731 461726
      457724 452721 450719 450716 453711 452703 445705 443710
      441711 440709 436703 430698 437688 441679 445673 448669
      453665 456659 458654 461649 459646 453649 441656 436660
      430665 425669 420671 417673 414675 409678 401685 398690
      395694 391703 393711 395717 397720 397722 395725 391730
      387735 383741 380746 381750 388761 389768 389771 391773
      395778 395782 394785 386792 379800 376806 372813 374815
      377817 379816 381813 386809 391807 394812 398816 399827
      403832 405836 405842 404849 405856 408861 410869 413880
      416899 419914 421919 424924 429926 433930 433950 435956
      435961 438971 438975 435978 434985 438990 455007 461015
      464019 468024 476032 484037 493044 505050 514051 517046
 0.01 290062 291058 289058 287060 285062 283064 282065 280067
      278070 277073 277078 279078 281076 283074 284072 286070
      288067 289064 290062
 0.25 473873 473868 473863 473858 472854 470852 468850 466851
      466856 466861 466866 466871 467875 468878 471878 472875
      473873
 0.25 463822 456810 452807 447806 441805 435804 432800 430793
      428786 422787 418792 415797 415805 415814 420827 431828
      438829 445828 450829 454830 457829 463822
 0.25 447860 445858 443857 438856 434856 427856 420857 418863
      421868 428868 433869 440868 444865 447860

24HR QP VT 13/12Z
 0.01 513291 508285 503279 500277 497273 493269 487262 486260
      485254 485250 489249 496250 504253 508254 510254 518257
      522258 524261
 0.01 487614 493622 498632 506651 510664 514677 518688 520692
      521699 523716 522730 521736 522742 519753 517758 514761
      512765 508769 503770 500773 490775 484777 482777 481780
      483793 484807 483811 478814 471818 467820 463824 458831
      455834 452834 447834 442832 435829 431828 429824 426821
      422823 419826 415825 412821 410816 409809 407805 404801
      401802 398807 396812 394816 390819 374822 368828 364831
      361836 357838 354838 352836 356828 357823 360819 365813
      373808 378801 384794 388791 393789 401783 405781 406778
      404765 403758 404753 405741 402729 396723 393720 388717
      384716 379719 373724 365729 362732 359735 345747 338753
      330759 321762 315763 314761 315750 316745 318741 329728
      342713 347706 351700 357692 359687 362684 377674 406649
      413644 422636
 0.01 540000 540990 538981 531967 527962 524960 521958 515955
      510951 506945 501942 493941 487939 479939 475939 472937
      457937 451938 444937 438934 433935 433938 435945 439949
      449959 461964 470965 471968 470972 470977 472979 477984
      489991 493995 499999 509009 514012 516015 520015 527015
      531010 540000
 0.01 481877 480868 478860 475852 471847 469846 465845 462845
      460848 453851 448850 442848 436849 431855 425854 417844
      412828 409823 404820 401818 398818 395821 398829 403834
      404849 411861 421870 433871 441871 445871 449872 453871
      458874 462879 463883 463888 463894 465899 468899 472893
      476887 480882 481877
 0.01 263782 263778 260778 255784 251789 247795 245803 243809
      246813 252808 256802 259796 261788 263782
 0.25 504689 504679 502671 498659 496651 493645 488636 482629
      477627 472627 466630 462634 451637 448638 444643 443648
      439653 436656 434662 430672 428677 427683 429689 429695
      422704 415710 413715 413723 415728 418733 425740 430742
      434742 438739 440741 437743 433744 428748 426761 423772
      414792 414799 415807 417812 423811 431806 437798 437782
      440769 443766 446763 456757 459758 462756 466753 478751
      486745 493738 497733 499728 502715 503708 503701 504689
 0.25 473877 473875 473874 472873 471872 469870 468868 468866
      467864 465864 465866 466868 466870 466871 467873 468874
      468875 469878 469879 470880 471881 472880 473878 473877
 0.25 446741 444740 442738 442737 441738 441740 441742 443744
      444744 446742 446741
 0.25 450806 450804 448803 446803 445803 444805 445807 447809
      449810 450809 450806
 0.50 493689 493682 492674 489660 485649 483645 479643 477648
      476653 476659 478663 477666 475664 476679 477686 477691
      478698 481701 486701 490698 492695 493689
 0.50 456670 456664 454661 452657 448656 444658 442661 439668
      437676 435680 435684 435689 435695 437701 439704 442705
      446703 449697 451688 454680 456672 456670
 0.50 445756 444754 442753 437754 434758 432761 429766 428772
      429779 430781 432781 435778 436773 437767 439763 442760
      445756
 0.50 429793 429788 428785 424786 422788 421790 419794 419797
      418799 418804 419807 422806 424804 425801 427798 428795
      429793

$$




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