Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 240700
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
300 AM EDT TUE OCT 24 2017


PRELIM DAY 1 QPF DISCUSSION
VALID OCT 24/1200 UTC THRU OCT 25/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

...GREAT LAKES...

STRATIFORM LAKE ENHANCED RAINFALL ON THE BACKSIDE OF A STRONG LOW
PRESSURE CENTER WILL CONTINUE ACROSS THE GREAT LAKES TODAY...WITH
THE INTENSITY GRADUALLY DECREASING AS WE HEAD INTO TONIGHT.
OVERALL MODELS ARE IN GOOD AGREEMENT ON THE SETUP...WITH A MULTI
MODEL BLEND PREFERRED FOR QPF. DID LEAN TOWARDS THE HIGH RES
GUIDANCE...WHICH HAVE A MORE REALISTIC DEPICTION OF THE LAKE
ENHANCED PRECIPITATION. LOOKING AT AMOUNTS OF 0.5"-1" ACROSS MUCH
OF WESTERN MI INTO THE UPPER PENINSULA...WITH LOCALIZED 1-2"
TOTALS OFF OF CENTRAL LAKE SUPERIOR.


...NORTHEAST....

A LONGWAVE MID/UPPER LEVEL TROUGH AND A SURFACE COLD FRONT WILL
PROGRESS EASTWARD THROUGH THE PERIOD. STRONG SOUTHERLY FLOW OUT
AHEAD OF THIS FRONT WILL TRANSPORT ANOMALOUS MOISTURE
NORTHWARD...WITH PWAT VALUES AROUND THE CLIMATOLOGICAL 95TH
PERCENTILE (1.5"-1.8"). INSTABILITY WILL BE LIMITED...BUT WITH THE
NEGATIVELY TILTED TROUGH...SHOULD BE ABLE TO GET A NARROW CORRIDOR
OF MARGINAL INSTABILITY ADVECTED OUT AHEAD OF THE FRONT. THIS
SHOULD SUPPORT SOME EMBEDDED HEAVIER CONVECTION...AND THE
POTENTIAL FOR RAINFALL TOTALS APPROACHING 1-1.5" IN AN HOUR. TO
START THE MORNING SHOWERS AND EMBEDDED CONVECTION SHOULD BE IN A
FAIRLY WEAK AND UNORGANIZED STATE. HOWEVER THE MODEL CONSENSUS
SUGGESTS WE SHOULD SEE AN INCREASE IN COVERAGE AND INTENSITY BY
LATE MORNING OR EARLY THIS AFTERNOON FROM EASTERN NY SOUTH INTO
NJ.

IN GENERAL THE FRONT SHOULD BE PROGRESSIVE IN NATURE..WHICH SHOULD
LIMIT THE UPPER LIMIT OF RAINFALL MAGNITUDE. HOWEVER IT DOES LOOK
LIKE THE FRONT WILL SLOW UP SOME THIS MORNING/AFTERNOON...WHICH
SHOULD INCREASE THE DURATION OF HEAVIER RAINFALL RATES. WITH THE
MEAN FLOW PARALLEL TO THE BOUNDARY...WILL LIKELY SEE SOUTH TO
NORTH TRAINING OF CONVECTIVE CELLS. AGAIN THE DURATION OF THIS
TRAINING SHOULD NOT BE ALL THAT LONG...BUT ENOUGH TO PRODUCE A
WIDESPREAD 1-2"...WITH EMBEDDED TOTALS OF 2-4" FROM EASTERN NY
INTO NEW ENGLAND. GIVEN THE DRY ANTECEDENT CONDITIONS..RAINFALL OF
THIS MAGNITUDE WILL PROBABLY NOT CAUSE WIDESPREAD FLOODING
CONCERNS. HOWEVER TOTALS AND RATES OF THE EXPECTED MAGNITUDE WILL
HAVE THE POTENTIAL TO PRODUCE FLASH FLOOD CONCERNS IN MORE URBAN
AREAS. WHILE IN GENERAL RAINFALL MAGNITUDE SHOULD BE A BIT LOWER
OVER NORTHERN NY INTO NORTHERN NEW ENGLAND GIVEN LOWER
INSTABILITY...LIKELY TO SEE SOME OROGRAPHIC ENHANCEMENT OT THE
TOTALS FROM VT INTO NORTHERN NH AND WESTERN ME. THIS SHOULD ALLOW
FOR SOME LOCALIZED AMOUNTS AS HIGH AS 3-4" HERE AS WELL.

GIVEN THE GOOD AGREEMENT SEEN IN THE GUIDANCE...WPC QPF FOLLOWED A
MULTI MODEL BLEND...ALTHOUGH DID WEIGHT THIS BLEND MORE TOWARDS
THE HRW ARW AND HRW ARW2...GIVEN THEIR NORMAL SUPERIOR PERFORMANCE
WITH CONVECTIVE QPF. OVERALL THE NEW WPC QPF IS NOT A WHOLE LOT
DIFFERENT FROM CONTINUITY...ALTHOUGH IT IS A BIT QUICKER WITH THE
CONVECTIVE PROGRESSION. THUS RESULTS IN LOWER TOTALS ON THE
WESTERN SIDE OF THE EVENT OVER PA/NJ...AND HIGHER TOTALS ACROSS
EASTERN NEW ENGLAND.

CHENARD


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

24HR QP VT 25/12Z
 0.01 531197 530190 527184 524179 524171 522166 519166 515169
      514174 515177 516185 516193 521198 525201 530199 531197
 0.01 511252 513239 514229 512224 509221 508219 504217 500216
      498219 498229 496235 494238 489242 485249 482257 478264
      475273 472282 473290 476297 483299 489294 494290 498284
      502278 509259 511252
 0.01 524836 524828 522822 519810 517803 516797 513791 512786
      508774 508768 505761 500737 496725 494718 493710 491688
      490680 488678 486674 483674 471665 469663 463665 452668
      441671 436672 431672 389683 385682 382685 373690 364696
      360698 356700 329716 320721 311726 303730 297732 294735
      290737 285739 277744 265755 241776 237779 236783 233789
      226806 219823 216831 217835 221837 235841 237841 240840
      242842 243855 247853 254847 265836 270832 275826 281819
      284816 288814 297809 304804 310797 316791 329780 338775
      343773 349772 384762 402763 420766 456772 458775 458778
      456777 453774 447775 441776 439779 435782 433786 424801
      419808 418810 414809 410807 407808 402808 400811 398814
      395812 395809 399799 400795 396796 388801 375812 367817
      365820 364826 361829 355830 352834 353835 355837 358835
      360834 369829 372824 373820 376818 380816 385817 386820
      384822 383825 385827 391833 393835 394840 394846 393852
      391865 389876 389883 391887 392895 395897 396908 404912
      415914 424915 430916 434919 437921 440921 440914 438909
      435903 438894 443889 446886 448885 451886 454897 455902
      453908 453913 453920 460926 486950 498964 504970 510976
      515976 517973 520966 522957 524952 524944 525939 525931
      522928 517929 513930 508931 504929 501924 496917 493915
      490911 476900 478897 481896 487893 493892 496890 501884
      510883 514882 514874 515870 517869 520866 523861 523855
      524836
 0.01 368871 368865 367858 364856 360856 356859 356863 355868
      355874 356881 358883 363883 365880 367876 368871
 0.01 275013 276010 275007 273003 268998 260994 253989 245988
      242991 241996 244004 249011 255016 261022 267021 269019
      275013
 0.25 503265 501262 499259 498258 495255 492256 491258 491260
      491266 491268 492271 496273 497272 499269 501267 503265
 0.25 517840 517824 514813 510804 505799 496797 488797 480799
      470799 465800 460802 452805 444808 437812 432820 425824
      421831 417839 415850 411859 407866 405870 405875 404887
      405892 408895 411897 416896 422892 428885 433879 449872
      452871 456872 458876 458884 458890 460897 461908 464907
      466903 468899 470893 483885 486882 490880 494880 498878
      505873 510868 514863 517856 517840
 0.25 484702 484695 482691 479688 475687 462683 454683 448684
      434691 427695 420694 411696 402699 395701 389707 375714
      343728 328734 319744 305755 292763 281771 268779 254787
      242796 234806 228819 226823 228825 232826 234829 249830
      256827 263824 275816 282812 288808 300798 322780 335771
      343768 350763 357759 365757 380756 400753 416755 421756
      426760 433762 438762 442760 450756 454755 458757 461759
      465757 469750 471742 478738 482732 483727 485722 484702
 0.25 432802 431801 430799 430797 429798 426800 424803 423806
      422808 421811 420816 422819 424817 425815 426812 428810
      429807 431804 432802
 0.50 515850 515843 515836 513825 506808 504805 500806 496812
      487823 481830 476835 472837 468837 464837 460839 435849
      439842 437840 433839 423849 418855 415863 416882 419882
      422879 426874 432868 440868 448869 452867 457868 460876
      461883 460890 462895 465896 468893 472887 478884 481882
      483878 485874 489873 496875 502870 511861 514856 515850
 0.50 480696 478693 473693 466694 464694 463691 461687 459686
      454688 448690 442694 429703 420704 412706 406710 400715
      395720 386722 371724 366724 361725 351727 344730 337734
      331739 326744 316754 303763 290771 279778 265785 257788
      251792 240803 232814 231816 231821 233823 237823 250825
      265819 277813 284810 289805 300794 312785 322777 328772
      335769 344766 348760 363753 371752 379752 385754 392752
      400750 410749 417749 420750 423748 425745 429744 430755
      432759 435759 442757 445754 446748 445744 446743 451741
      460740 468737 478724 480718 480708 479701 480696
 0.50 460856 461854 460853 460854 460857 460856
 1.00 509854 509844 507835 506831 504830 499834 497840 494845
      491851 490858 494862 500861 505858 509854
 1.00 471718 454713 456710 455707 453704 453700 457693 456692
      452693 449694 445698 439703 436706 432707 423710 416712
      409718 404722 401725 401730 383736 377741 371737 364733
      358731 352731 345734 339738 331743 328745 327749 325752
      322755 310764 298771 284780 269786 256791 249796 245803
      271812 273810 275808 277809 281809 284807 288801 294797
      305786 316778 329769 337765 341764 342759 343757 347754
      355751 370745 373743 378742 383742 386743 388745 392747
      402745 412744 418745 422745 423742 424739 428738 431740
      433743 442740 445737 444732 448732 449736 458736 464734
      460727 467722 471718
 1.00 481869 479863 474860 469858 467857 464859 461864 460871
      463876 465885 468880 471878 474879 478879 480877 481869
 1.00 478842 476841 474842 474843 473845 474848 475848 475847
      476846 477845 478843 478842
 1.00 466702 465702 464702 462703 464703 465703 466702
 1.00 456852 456848 454847 451847 449848 446850 444852 443854
      441858 443862 445863 448864 452863 453862 455859 456854
      456852
 1.00 428860 428857 427855 425855 424856 422857 422858 421860
      421861 420863 419865 420867 421869 422867 423867 424865
      425865 426863 426862 427860 428860
 1.50 468873 468870 467869 467868 466866 465864 465863 464862
      463864 462865 462866 461869 461871 462873 463873 464875
      464876 465878 466881 466880 467878 467875 468875 468873
 1.50 457724 456724 454725 456725 457724
 1.50 450704 450703 448704 447705 448706 450705 450704
 1.50 449711 446709 445706 440710 435714 431718 420714 414718
      411720 411723 413730 410733 398740 400742 404742 411741
      418739 422736 434731 448727 440721 444715 449711
 1.50 427724 426724 425725 424725 425725 426724 427724
 1.50 365739 356733 353733 350735 345737 335744 331746 331751
      332754 329757 325759 316766 308772 299778 289783 284785
      280785 270791 268793 270795 275796 285798 289795 293792
      298789 302785 310779 320773 329767 334764 338760 338754
      341750 355747 360745 364741 365739
 1.50 270804 271802 270801 268801 266801 265801 263802 262803
      261804 261805 261806 262807 263807 264806 265806 267805
      269805 270804 270804
 1.50 262796 260796 259796 257797 256797 255799 257800 259799
      261799 262796 262796
 2.00 444713 443710 442710 441711 440711 439712 438714 439716
      439717 441717 443715 444713
 2.00 442725 440725 439725 437725 436727 437728 439727 441727
      442726 442725
 2.00 424732 422730 420730 416731 415732 412734 410736 407738
      410739 412739 414739 417737 421735 422733 424732
 2.00 420721 419719 418718 417718 416719 416722 417723 419722
      420721
 2.00 406738 405738 403738 401739 402740 403739 405739 406738
 2.00 356739 354737 353737 351738 349739 348740 347741 346742
      345743 346744 348744 350743 351742 352742 353741 355741
      356739
 2.00 332761 328761 325763 321765 318768 314770 309773 306776
      308776 312775 316772 320770 323768 328766 331763 332761
 2.00 305778 304778 303778 302778 303779 304778 305778
 2.00 280792 278791 277790 276790 276791 277792 279794 280792
      280792
 3.00 443713 442712 441713 440714 441714 442714 443713

$$




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