Quantitative Precipitation Forecast
Issued by NWS

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857
FXUS04 KWBC 090936
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
436 AM EST SAT DEC 09 2017


FINAL DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION
VALID DEC 09/1200 UTC THRU DEC 12/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

06Z UPDATE...
ONLY MINOR CHANGES WERE MADE TO PRELIM GUIDANCE BASED ON SAT/RADAR
TRENDS.


...MID ATLC/NORTHEAST...

LOW PRESSURE IS EXPECTED CONSOLIDATE AND INTENSIFY WELL OFF THE
DELMARVA COAST SATURDAY IN RESPONSE TO COMBINATION OF RAPIDLY NEWD
SHEARING LOWER MS/SE U.S. S/WV TROF AND DIGGING S/WV TROF THROUGH
THE MIDWEST/OH AND TN VALLEYS.  THE LOW IS GENLY EXPECTED TO TRACK
ACRS NOVA SCOTIA BY SUN MORNING.  MODELS CONTINUE TO CONVERGE
ALONG WITH REASONABLY GOOD RUN TO RUN CONTINUITY WITH THE
EVOLUTION OF THIS SYSTEM AND HAVE SETTLED BACK FROM THE EARLIER
WWD TRENDS WITH THE QPF AMOUNTS.   HEAVIER QPF AMOUNTS ARE FCST TO
REMAIN OFF THE COAST WITH THE STGR LOW LEVEL MSTR FLOW ALONG AND
JUST WEST OF THE LOW TRACK..BUT WEAKER 7H-5H LIFT WELL WEST OF THE
SFC LOW TRACK WILL GENLY SUPPORT AN AXIS OF LIGHT TO MDT PCPN
AMOUNTS...MUCH OF IT AS SNOW GENLY ALONG THE I-95 CORRIDOR EAST
EXTENDING NEWD THROUGH CNTL/ERN MAINE THIS PD.  AGAIN ONLY MINOR
MASS FIELD AND QPF DIFFERENCES WERE NOTED PARTICULARLY BETWEEN THE
NAM/GFS/12Z ECMWF AND THEREFORE A GENLY BLEND OF THESE SOLNS WERE
GENLY FOLLOWED. FOR MORE DETAIL ON WINTER WEATHER..SEE QPFHSD
DISCUSSION.


...FLORIDA...

TSTMS SHOULD BE FAIRLY WIDESPREAD AT THE BEGINNING OF THE DAY 1 PD
AHEAD OF AN ADVANCING COLD FRONT OVER THE FL PENINSULA..BUT THESE
ARE EXPECTED TO PROGRESS FAIRLY RAPIDLY FROM WEST TO EAST ACRS THE
STATE BY EARLY AFTERNOON IN RESPONSE TO S/WV TROF SHEARING
NEWD/EWD ACRS THE SE STATES.  WITH AXIS OF 2" PWS FEEDING IN AHEAD
OF THE FRONT OVER THE ERN GULF...EXPECT SOME MDT TO LOCALLY HEAVY
RAINS TO AFFECT THE SRN PORTION OF THE STATE THRU EARLY AFTN
BEFORE COOLER/DRIER AIR PUSHES IN FROM THE WEST.  LEANED A BIT
MORE TOWARD A CONSENSUS OF HI RES GUIDANCE HERE WITH AN AXIS OF
.50 TO 1+" RAINS.

...GREAT LAKES..OH VALLEY/CNTL AND SRN APLCNS...

MODELS SHOW DECENT AGREEMENT WITH HANDLING OF DIGGING S/WV TROF
THAT IS FCST TO DROP SEWD FROM THE MIDWEST THRU THE OH VALLEY/ERN
TN VALLEY REGION BY LATE SAT.  SOME WEAK SYNOPTIC SNOWS
ACCOMPANYING THE ASSOCD SFC LOW THAR WILL TRACK ACRS LAKE MI EARLY
SAT WILL BE FOLLOWED BY LAKE EFFECT SNOW BANDS AS STG COLD
ADVECTION OCCURS BEHIND THE LOW WHICH IS EXPECTED TO TRACK TOWARD
QUEBEC PROV.  SNOW BANDS ACCOMPANYING THE MID/UPR S/WV ARE
EXPECTED TO SPREAD INTO THE CNTL/SRN APLCNS BY SAT NIGHT AIDED BY
INCREASING WLY/NWLY UPSLOPE CONDS.  PLEASE SEE QPFHSD DISCUSSION
FOR FURTHER DETAILS ON SNOWFALL AMOUNTS.



DAYS 2/3...


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

A BAROCLINIC ZONE WITH MULTIPLE WAVES OF LOW PRESSURE WILL CROSS
THIS PORTION OF THE COUNTRY ON SUNDAY INTO TUESDAY MORNING.  THE
SYSTEMS WILL HAVE LIMITED MOISTURE ASSOCIATED WITH CLIPPERS WITH
PRECIPITABLE WATER VALUES RANGING FROM 0.50 TO 0.25 INCHES AND
LESS.  THE FIRST ASSOCIATED SHORT WAVE WILL MOVE ACROSS THE LAKES
ON SUNDAY INTO MONDAY MORNING.  LAKE EFFECT/LAKE ENHANCED SNOW
WILL DEVELOP OVER THE REGION WITH THE MAXIMUM QPF DEVELOPING
DOWNWIND FROM LAKE ERIE AND LAKE ONTARIO ALONG THE SOUTHEAST COAST
WITH MAXIMUM QPF AMOUNTS RANGING FROM 0.75 TO 1.00 INCHES AND 0.50
TO 0.70 INCHES ... RESPECTIVELY ON SUNDAY INTO MONDAY MORNING.  A
SECONDARY MAXIMUM WILL DEVELOP ALONG THE SOUTHERN COAST OF LAKE
SUPERIOR WITH MAXIMUM QPF AMOUNTS RANGING FROM 0.35 TO 0.40
INCHES.  QPF AMOUNTS WILL BE MODEST OVER PARTS OF THE UPPER
MISSISSIPPI VALLEY WITH AMOUNTS GENERALLY LESS THAN 0.25 INCHES.

ON MONDAY INTO TUESDAY MORNING ADDITIONAL SHORT WAVE ENERGY WILL
MOVE INTO THE REGION PRODUCING GENERALLY 0.10 INCHES OF QPF FROM
THE UPPER GREAT LAKES TO THE NORTHERN MID-ATLANTIC COAST.  THE
MAXIMUM QPF WILL DEVELOP ALONG THE EASTERN COAST OF LAKE MICHIGAN
WITH MAXIMUM QPF AMOUNTS RANGING FROM 0.30 TO 0.45 INCHES ON
MONDAY INTO TUESDAY MORNING.  A SECONDARY MAXIMUM WILL DEVELOP
ALONG PARTS OF THE SOUTHERN AND SOUTHEASTERN COAST OF LAKE ERIE
WITH QPF AMOUNTS RANGING FROM 0.25 TO 0.35 INCHES.  WPC USED A
BLEND OF THE GFS/ECMWF/UKMET FOR THE STARTING POINT FOR THE QPF
FORECAST ON SUNDAY INTO MONDAY MORNING.  ON MONDAY INTO TUESDAY
MORNING ... WPC USED A BLEND OF THE GFS/ECMWF/NAM FOR THE STARTING
POINT OF THE MANUAL GRAPHIC.


SULLIVAN/ZIEGENFELDER


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

24HR QP VT 10/12Z
 0.01 485614 491617 495621 496625 498630 499636 501647 502655
      501661 499670 495679 490687 481701 476708 475710 471709
      457715 452720 447724 441730 436736 426747 420754 414759
      408766 401771 392784 389790 393790 396788 414786 416787
      419787 425782 430778 432773 433768 432750 434746 437748
      440752 442758 443761 446761 452754 457749 462747 465745
      472743 475745 478748 479751 480757 481766 476782 475793
      472801 464814 461818 460824 460834 463837 468838 471839
      476842 497863 501868 504872 505876 508893 510903 510908
      508911 502919 499921 486908 481902 476905 470902 468900
      467903 464907 462906 461901 461895 463886 462880 460877
      457871 460864 461860 460854 455858 452865 446870 438875
      434876 429877 422876 411875 394877 385876 381874 379871
      377863 375861 371860 368858 364859 359859 357861 353861
      351859 355853 358850 361847 364842 346840 348837 345836
      341835 335831 334822 335815 338808 341799 336794 330797
      314802 301809 297811 294816 288822 279834 268843 266845
      262846 256848 246850 241850 237849 229848 225843 223835
      221824 220804 220792 220784 220779 225776 232771 231766
      232763 237758 250747 259740 265736 271732 283723 296715
      310704 317700 324694 329689 335684 346677 363669 367667
      369665 375660 379654 384648
 0.01 467331 470331 472331 475330 477330 480330 482329 485328
      488328 490326 492326 494324 496323 498321 500319 502318
      505311 514285 522264 522258 520253 516243 512233 504227
      500228 497233 497239 496244 488248 485251 481252 478255
      475260 469268 462273 455277 451279 447282 441287 427297
      419302 412305 410307 411309
 0.01 440320 439319 437318 435316 434316 432316 430315 429316
 0.01 523997 522994 520993 518990 515988 513987 511988 512992
      513995 515997 516000 518002 520000 522999 523997
 0.01 410810 408808 406806 405806 403808 403809 401809 400811
      402813 403812 405812 407812 409812 410810
 0.25 473619 478626 483635 484644 484652 483664 478671 473677
      467685 462693 450705 447709 445714 442717 436719 428724
      424729 418736 412742 399753 393761 386768 380773 377773
      373772 366767 358767 350771 342775 323783 308791 294799
      279808 264819 258826 254832 249838 242841 239841 235839
      230833 228828 227823 227809 229792 244783 259774 276765
      290756 296750 293749 288750 279753 271758 267760 260762
      251760 249755 252753 258748 274739 306720 313716 321711
      334701 340696 342693 347690 356685 363679 375668 389656
      397648 406642
 0.25 514266 515258 514251 512245 508243 505246 505254 504260
      499259 494257 489257 484258 480261 475271 472276 469279
      461286 456294 444310 447314 453314 461313 469309 473312
      478313 488313 492312 496309 502300 507290 509285 510277
      511272 514266
 0.25 450814 447813 444814 440814 437814 435816 435818 437822
      439824 441825 444824 445822 446818 447816 450814
 0.25 436765 436763 436762 436763 436765 436766 436765
 0.25 440830 440829 438828 437830 438831 440830 440830
 0.25 427867 426862 424861 420860 419860 415859 412859 410859
      408860 408863 410866 412867 414868 417869 421869 424869
      427867
 0.25 383807 383806 382807 383807 383807
 0.50 465622 470625 474635 475642 476650 473657 463668 458674
      452680 443693 433707 422716 411727 406732 400737 386748
      382752 377754 374753 367752 360754 347763 333772 307787
      295795 280805 269812 263817 259821 254827 248831 243832
      239831 235829 233826 231819 231811 232806 234803 238798
      243793 249789 264780 271777 278774 288764 299755 313745
      322734 324727 321722 321718 324715 329710 344700 367682
      390660 403650 409646 416642 422640 428637 437632
 0.50 505287 504278 502275 501271 497264 491260 485261 482262
      480266 479274 480279 482283 483286 485289 492294 499294
      502293 504289 505287
 0.50 417865 415864 414864 413866 414866 416866 417865
 1.00 496275 497273 496272 495270 495269 493268 491267 490267
      488265 487267 487270 488270 489271 490273 492273 493274
      494275 495276 496275
 1.00 459644 459642 458639 456639 455640 455642 454643 454646
      453648 454651 455651 455650 456650 458648 458647 459645
      459644
 1.00 450642 449638 447635 445634 443635 435641 429645 416652
      405661 381679 370686 359695 354699 350704 345710 346713
      348716 343726 334737 325747 313756 303765 292772 288777
      284781 270789 258797 248804 241814 242819 244822 247823
      251822 259815 271806 295790 317777 328769 339759 345755
      348749 353745 359742 373737 386727 395718 405710 414699
      419693 425688 430683 434676 441665 443659 447653 450647
      450642
 1.50 427662 426656 422656 415660 402669 389679 377690 371696
      366702 364705 364712 365719 368721 372719 379715 386710
      392706 398699 402693 408686 413682 418679 421676 425669
      427662

24HR QP VT 11/12Z
 0.01 510991 511981 511971 506956 502939 499932 496927 482902
      474890 477882 480880 482877 481868 479861 478849 478838
      477826 475818 472812 469808 464802 460795 458787 455780
      453779 449781 446784 443784 441780 441776 442767 444760
      446755 448751 452750 455745 458738 459734 459729 459724
      462723 465718 472705 475699 480694 480684 481680 480675
      475668 472665 469663 459664 453663 446665 436675 431680
      428683 422689 419692 415692 410696 407702 405710 403717
      401725 402730 404734 409733 412729 416728 418729 420726
      420722 418711 420708 423709 434705 440700 443692 443688
      445683 448682 450684 453689 455698 453701 449703 445704
      443707 440711 438718 438722 437725 435724 433727 431729
      429728 425732 429731 431734 435733 435736 426745 422746
      420745 418751 415755 412756 415757 417760 413765 414776
      407782 398791 388792 383798 380804 380808 382807 386805
      389807 398816 403821 404827 406827 412825 417828 421825
      424820 427804 431790 433790 435794 432802 432805 429807
      429812 430817 434824 433832 432837 430840 428841 426845
      422853 419855 418858 408864 407866 408868 409873 411876
      416891 420903 427917 427921 430925 433931 441942 445949
      449954 452959 453962 453968 456974 461977 467981 470983
      470987 472992 468994 465996 466000 468004 470006 473007
      479007 482009 485010 489010 492008 495007 497010 501017
      503020 505019 507003 510991
 0.01 463878 461874 459869 457864 455862 453860 450862 448865
      443866 441867 442870 445872 449874 452876 456879 459881
      462881 463878
 0.01 445836 444831 442829 440830 439832 437835 437840 436842
      436847 436852 439851 440849 442846 442844 443839 445836
 0.01 367815 364815 363817 361819 358821 356822 356826 357826
      359825 360828 362827 363823 364820 365818 367815
 0.25 488967 488964 487964 486963 485964 486966 487967 488967
 0.25 468856 469853 468851 468850 467848 466848 465851 465852
      465854 465856 465858 465861 466861 467860 468858 468856
      468856
 0.25 469878 469875 468873 467872 467871 466869 464868 464871
      464873 465876 466878 468880 469878
 0.25 456806 454801 451797 449797 446800 443804 441808 440813
      442817 446818 449820 454818 455813 455807 456806
 0.25 451848 451846 450845 449845 448848 449850 449851 450850
      451849 451848
 0.25 442757 442755 441752 441750 440748 438749 436750 435751
      433752 432754 432757 432759 432761 433764 434765 435766
      436766 438766 438765 439763 440762 441760 441759 442757
 0.25 431781 430775 427779 425782 422786 421790 420795 419801
      422805 425801 427796 428792 429787 431781 431781
 0.50 440757 439755 438754 437755 436756 435758 433757 433759
      433761 434762 436761 438762 439760 440757
 0.50 429788 429786 429783 427783 426784 426785 424787 423789
      423790 422792 422794 422796 423797 425796 426793 427791
      428790 429788


24HR QP VT 12/12Z
 0.01 501274 502270 502266 500259 498252 494247 492242 489240
      487243 486248 488256 490263 493268 494271 497273 501274
 0.01 497985 495981 492978 488979 487983 489986 490994 490997
      488000 486001 485000 478993 472989 468987 465984 461982
      461974 461966 459962 454956 450954 445954 444955 447959
      450970 450976 451979 457987 458991 460995 458998 454999
      451996 445991 440983 435977 427973 424974 424978 428982
      431983 432991 432997 435000 438002 444998 446003 449008
      456010 470039 474038 478040 479044 481048 487043 489040
      492043 494041 494036 492031 490021 489015 487010 485007
      486004 490003 497985
 0.01 494944 494939 492932 489923 485914 484909 484903 482892
      483881 485875 484867 483862 483854 484849 486843 484836
      479829 475822 472819 470812 469805 467801 460785 454776
      452773 451767 454748 456739 455732 456728 456720 457715
      455702 441673 437675 434679 430687 424693 418693 415692
      405692 402692 399695 394701 391708 388719 389731 392755
      392761 389766 387775 388779 392780 393785 393790 387797
      382804 376810 370815 362820 361823 363825 366822 368825
      369828 372833 376831 377827 379823 381821 384822 389842
      391847 394846 397843 398840 400842 403862 408868 405877
      406882 407885 408889 409889 413884 419877 423879 425884
      425897 425900 427905 431912 434915 436916 440915 442920
      446930 449934 453937 459940 465946 466949 467956 464962
      467964 471964 476964 480967 482964 484959 491954 493947
      494944
 0.01 294058 295052 291051 288054 286058 284062 282065 279069
      277073 278078 281076 284074 287071 289067 292063 294059
      294058
 0.25 470858 469853 467851 462849 456847 453843 451842 450845
      451852 448857 445858 440859 434858 428859 424862 426867
      431870 438870 445868 450866 455862 459859 462858 463861
      465867 469861 470858
 0.25 459810 459805 456801 454800 451802 447809 448815 447817
      440815 442820 447826 451833 453836 456835 457827 458820
      458814 459810
 0.25 445790 445785 443780 441774 437772 436780 436786 433790
      430793 435794 438796 442796 444793 445790
 0.25 429795 428792 426789 423787 419792 417797 416804 417808
      419809 420818 423822 426822 427819 429812 426805 427798
      429795
 0.25 406733 406731 405729 404727 403727 402728 401730 401732
      403734 405735 406733
 0.50 455811 454809 453808 452808 452809 452811 452812 454811
      455811


$$





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