Quantitative Precipitation Forecast
Issued by NWS

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247
FXUS04 KWBC 080846
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
345 AM EST FRI DEC 08 2017


PRELIM DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION
VALID DEC 08/1200 UTC THRU DEC 11/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR

DAY 1

GULF COAST INTO THE SOUTHEASTERN U.S. AND MID ATLANTIC REGION...

THE EJECTION OF AN INITIAL POS TILTED UPPER TROF ACRS THE SRN
PLAINS ACROSS THE LOWER MS VALLEY INTO THE SOUTHEAST BY SAT
MORNING WILL CONTINUE TO SUPPORT A RATHER WIDE SWATH OVERRUNNING
PCPN FROM THE GULF COAST REGION SPREADING THOUGH ERN PORTIONS OF
THE MID ATLC REGION BY SAT MORNING. THE UNSEASONABLY LOW LATITUDE
HEIGHT ANOMALIES ASSOCD WITH THE UPPER TROF WILL CONTINUE TO
SUPPORT SOME UNSEASONABLY EARLY SEASON SNOWS ALONG THE WRN FRINGE
OF THE PCPN SHIELD OVER THE GULF COAST REGION THAT WILL SPREAD
NEWD THROUGH PARTS OF THE SRN APLCNS INTO NRN VA/SRN MD. SEE
QPFHSD FOR MORE DETAILS ON SNOWFALL AMOUNTS.  OTHERWISE...MODEL
DIFFERENCES REVOLVE AROUND THE TIMING OF THE SRN STREAM IMPULSE
AND EVENTUAL INTERACTION WITH S/WV ENERGY DIVING SEWD ACRS THE NRN
GT LAKES.  THE NAM REMAINS A SLOWER OUTLIER SOLN ..WHILE THE
GFS..UKMET AND 12Z EC ARE A BIT QUICKER AHEAD OF THE MORE NRN
STREAM ENERGY.  IN FACT..RECENT TRENDS OF THE THE UKMET AND GFS
HAVE SHOWN A GRADUAL NW TREND OF THE PCPN ACRS THE MID ATLC REGION
WHICH IS SUPPORTED BY THE 00Z CANADIAN GEM.  WHILE THIS TREND HAS
BEEN GENLY ACCEPTED HAVE TAKEN A BIT MORE CONSERVATIVE APCH IN
BLENDING CONTINUITY WITH THE LATEST GFS GUIDANCE THROUGH THE MID
ATLC REGION TO AVOID ANY WINDSHIELD WIPER EFFECT AS SLIGHT CHANGES
TO THE AMPLITUDE OR TIMING OF EITHER THE NRN STREAM OR SRN STREAM
IMPULSES WILL RESULT IN FURTHER SHIFTS IN THE QPF.
OTHERWISE...THE HEAVIER QPF AXIS NORTH OF THE FRONTAL BOUNDARY IS
EXPECTED FROM GA NEWD INTO SE VA AS STRENGTHENING RT ENTRANCE
REGION JET OVER THAT REGION NORTH OF THE FRONT WILL RESULT IN STG
BROAD SCALE ASCENT EVEN WITH LACK OF INSTABILITY.  WIDESPREAD 1 TO
LOCAL 2 INCH RAINS AREA EXPECTED ACROSS THIS AREA GIVEN EXPECTED
LONG DURATION OF MDT TO OCCASIONALLY HEAVIER RAINS.  ACRS FL...THE
WITH APPROACHING HEIGHT FALLS FRI NIGHT COINCIDENT WITH INCREASING
SWLY 85H FLOW AND PWS INCREASING TO NEAR 2" ALONG THE
FRONT...EXPECT TSTMS TO INCREASE IN COVERAGE ACRS THE CNTL
PENINSULA AS THE COLD FRONT GRADUALLY PUSHES EWD ACRS THE STATE BY
SAT MRNG.  GIVEN THE DEEP LAYERED UNIDIRECTIONAL FLOW AND
SUFFICIENT SHEER...SOME TRAINING LINE ELEMENTS MAY OCCUR THAT MAY
LEAD TO LOCALIZED HEAVIER RAIN IN EXCESS OF 2 TO 3 INCHES.  WHILE
SOIL CONDITIONS ARE RELATIVELY DRY HERE...COULD NOT RULE OUT SOME
ISOLD RUNOFF ISSUES IN USUAL SLOW DRAINING AREAS.

GREAT LAKES AND INTERIOR NEW ENGLAND...

WHILE SOME MINOR TIMING DIFFERENCES EXIST...MODELS GENLY AGREE ON
DROPPING A CLIPPER SYSTEM SEWD ACRS THE UPPER MS VALLEY FRIDAY
WHICH WILL BE ACCOMPANIED BY MAINLY LIGHT TO SPOTTY MDT SNOWS
FOLLOWED BY MORE GENERAL LAKE EFFECT SNOWS FROM WEST TO EAST AS
VERY STG COLD ADVECTION IS USHERED IN BEHIND THE SFC LOW LEADING
TO STG LOW LEVEL LAPSE RATES AS 85H TEMPS DROP TO -18 OVER LAKE
SUPERIOR BY SAT MRNG. MODELS GENLY SHOW DECENT AGREEMENT HERE AND
SO CHANGES FROM CONTINUITY WERE RELATIVELY MINOR.  FOR MORE
DETAILED INFORMATION OF SNOWFALL AMOUNTS..PLEASE SEE QPFHSD.


DAYS 2/3...


...EASTERN SEABOARD...

LOW PRESSURE OFF THE MID-ATLANTIC COAST ALONG AN ASSOCIATED
BAROCLINIC ZONE OFF THE COAST WILL MOVE NORTHWARD TO THE CANADIAN
MARITIMES OVERNIGHT SATURDAY AS THE BAROCLINIC ZONE SWEEPS OUT
EASTWARD OVER THE WESTERN ATLANTIC.  MOISTURE WILL POOL ALONG THE
BOUNDARY WITH PRECIPITABLE WATER VALUES RANGING FROM 1.50 TO 1.75
INCHES ON SATURDAY MORNING.  THE PRECIPITABLE WATER VALUES WILL
STEADILY DECREASE AS THE FRONT SWEEPS OUT TO SEA WITH THE
PRECIPITABLE WATER VALUES DROPPING OFF FROM 1.25 INCHES TO 0.50
INCHES LATE SATURDAY EVENING.  THE QPF WILL MOVE OFF THE
SOUTHEAST/SOUTHERN MID-ATLANTIC BY SATURDAY EVENING.  THE QPF WILL
MOVE OFF THE NORTHEAST COAST BY SUNDAY EVENING.  THE MAXIMUM QPF
WILL DEVELOP OVER SOUTHEAST FLORIDA ON SATURDAY INTO SUNDAY
MORNING WITH MAXIMUM QPF AMOUNTS RANGING FROM 1.25 TO 1.50 INCHES.
 ALL THE PRECIPITATION WILL BE RAIN OVER FLORIDA.  A SECONDARY
MAXIMUM WILL OCCUR OVER THE MAINE COAST WITH MAXIMUM QPF RANGING
FROM 0.50 TO 0.75 INCHES WITH THE PRECIPITATION MOSTLY AS SNOW.
THE QPF AMOUNTS WILL RANGE FROM 0.25 TO 0.50 INCHES ALONG THE
MID-ATLANTIC COAST AND 0.50 TO 0.70 INCHES OVER SOUTHERN NEW
ENGLAND COAST ON SATURDAY INTO SUNDAY MORNING.  ON SUNDAY INTO
MONDAY MORNING MOST OF THE QPF WILL TAPER OFF OVER NEW ENGLAND
WITH QPF AMOUNTS BEING MODEST WITH MAXIMUM QPF RANGING FROM 0.10
TO 0.25 INCHES OVER NORTHEASTERN MAINE.   WPC USED A BLEND OF THE
GFS/ECMWF AND THE IN-HOUSE-PSEUDO-BIAS-CORRECTED-QPF AS THE
STARTING POINT FOR THE MANUAL GUIDANCE.


...UPPER MISSISSIPPI VALLEY INTO THE GREAT LAKES/NORTHERN
APPALACHIANS...

MULTIPLE AREAS OF SHORT WAVE ENERGY WILL MOVE OVER THE AREA ON
SATURDAY INTO MONDAY MORNING.  LAKE EFFECT AND LAKE ENHANCED SNOW
WILL DEVELOP OVER THE AREA WITH MAXIMUM QPF AMOUNTS DEVELOPING
ALONG THE EASTERN LAKE MICHIGAN COAST WITH QPF AMOUNTS RANGING
FROM 0.25 TO 0.45 INCHES ON SATURDAY INTO SUNDAY MORNING.  A
SECONDARY MAXIMUM WILL DEVELOP ALONG THE SOUTHERN COAST OF LAKE
SUPERIOR WITH MAXIMUM QPF AMOUNTS RANGING FROM 0.25 TO 0.40 INCHES
LIKEWISE ON SATURDAY INTO SUNDAY MORNING.  ON SUNDAY INTO MONDAY
MORNING ... THE MAXIMUM QPF AMOUNTS WILL DEVELOP ALONG THE
SOUTHEASTERN COAST OF LAKES ERIE AND LAKE ONTARIO WITH MAXIMUM QPF
RANGING FROM 0.25 TO 0.40 INCHES.  A SECONDARY MAXIMUM WILL
DEVELOP OVER PARTS OF THE UPPER MISSISSIPPI VALLEY WITH THE NEXT
SHORT WAVE WITH MAXIMUM QPF AMOUNTS RANGING FROM 0.10 TO 0.25
INCHES.  WPC USED A BLEND OF THE GFS/ECMWF AND THE
IN-HOUSE-PSEUDO-BIAS-CORRECTED-QPF AS THE STARTING POINT FOR THE
MANUAL QPF.


SULLIVAN/ZIEGENFELDER


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

24HR QP VT 09/12Z
 0.01 483338 492326 501314 505308 508296 507292 505288 500282
      498281 495282 489284 482285 476287 464292 452296 439299
      432300 426301 419302 413304 410307 406308
 0.01 547944 547937 546933 543924 537921 529920 525920 521918
      514915 509916 505913 500906 486901 483899 481898 480895
      482884 483880 484873 483866 482859 480854 478851 473843
      471839 472835 474827 476817 476812 475807 474799 476794
      479787 487768 487764 488764 491765 498766 502765 504761
      506751 507740 506732 505725 501715 498712 495711 487714
      484715 481718 476724 472733 469740 466750 461760 460763
      459770 456776 451782 447790 442798 435804 429809 418823
      413828 410834 399846 394851 389858 387863 387869 393876
      397883 399890 403899 405903 408903 413905 415907 417912
      420914 427920 429924 431928 455942 460949 464957 469964
      474964 477967 486967 490967 494969 500972 504975 507976
      511978 516978 520978 522976 525971 528968 534963 542955
      546949 547944
 0.01 473695 471693 469694 463700 459701 458704 454710 457717
      456720 454723 447727 454726 458724 460721 463713 468707
      472701 473695
 0.01 442647 441642 439641 435639 429640 424640 419639 412642
      402649 398653 394658 386668 376680 369689 353705 337722
      318740 310748 298756 290761 278763 270761 264764 258764
      245767 237769 234774 235780 239780 242781 255783 261785
      264785 263788 256796 247804 239810 229818 222827 221829
      221834 222842 227855 230860 233865 233873 236877 245884
      249886 252892 256905 258913 259921 257927 253932 249936
      244938 241941 237946 235950 233956 232964 233973 234979
      234986 234002 238015 241020 248024 253026 259027 265017
      267012 266006 266998 270993 275983 283971 288960 294950
      303939 314921 321911 326901 349852 356844 362834 367824
      369822 369817 372812 377807 380801 386790 392778 394771
      396763 404740 409729 411723 415717 418712 421703 425690
      436666 437661 440656 442647
 0.01 452752 449751 450746 447741 445744 443749 441752 438752
      434746 433751 435756 437760 438765 439777 444771 448763
      451755 452752
 0.01 433785 431782 427784 425789 424794 422799 421804 420808
      423811 424808 427804 429800 431795 432790 433785
 0.25 502299 501293 499291 496290 488295 481300 473305 465309
      457314 457317 461322 471322 479321 487316 494311 498308
      501301 502299
 0.25 472892 472887 471884 468885 467888 466890 465895 465898
      465903 465905 469907 470902 471900 471895 472892
 0.25 472873 471868 471863 470860 468857 467854 465851 464856
      463859 462864 463868 464873 466876 467878 469878 470875
      472873
 0.25 466789 465785 460784 456785 452789 449798 445806 443810
      444815 452816 454822 455828 457834 459830 459823 460817
      461805 465795 466789
 0.25 455847 455842 452843 448850 448854 445857 441858 436856
      431853 424856 421859 421865 423869 426870 435869 442867
      447862 451855 454848 455847
 0.25 421661 419657 415657 408662 394675 369707 357719 351725
      342730 335736 329743 315757 304770 300773 295775 292778
      289781 284789 278796 275799 270802 261807 246815 239821
      235829 234833 234840 235846 237850 250865 257870 261872
      261876 262884 264897 266908 268912 272915 272921 270925
      265934 252944 245950 243953 241958 244963 248966 257970
      263970 266967 268957 272948 276941 285926 291919 295916
      299914 303911 307908 313901 325887 327884 328878 332870
      343852 353837 358829 362821 366812 369802 373791 378783
      382774 386763 392746 396736 400728 404719 408709 411698
      416687 419673 421667 421661
 0.25 252006 252004 252002 251000 251999 250998 249997 247996
      246997 244998 242000 242001 242002 242004 242006 243008
      245009 247009 249008 251007 252006
 0.50 457793 457791 456789 454791 453794 453795 452796 452799
      453800 455799 455798 456796 456795 457793
 0.50 406682 405679 402677 396681 386692 376705 364716 356726
      345737 340743 337745 332748 322758 313768 306782 295794
      289798 283802 270808 262811 256815 250819 245825 240831
      238840 239843 241845 246850 257858 264863 266865 267870
      267880 267883 269880 275876 280872 284866 287859 294854
      298854 297858 293865 289870 286876 283884 285889 288891
      294889 300885 305880 315867 320862 325858 330854 336850
      348838 352832 355824 357816 360808 362802 366794 374780
      378773 381764 386750 392735 399719 402712 404702 406692
      406682
 0.50 257949 257947 254947 252948 250950 248952 246955 245958
      246960 248962 252962 254960 255958 256956 257952 257949
 1.00 388726 388721 387717 384711 380712 377714 373717 364728
      356738 343757 334767 330771 324775 318783 310792 303803
      299807 296807 296804 296802 292801 287804 276809 264815
      253822 249826 246830 244836 246840 248841 261842 264841
      266843 269844 269849 273853 277851 281848 286845 298837
      303834 308831 316822 321821 324819 325821 318833 312845
      309856 313855 317851 333833 340823 343818 346812 352801
      360790 366781 372770 378757 383745 386735 388726
 1.50 379739 377735 374736 368743 361747 356749 353753 341764
      336771 330778 325784 320791 321796 325795 328794 330797
      329801 329805 336802 343797 350790 356785 361778 366771
      370761 377744 379739
 1.50 301817 295816 290814 280812 270816 261821 254826 251831
      251836 254838 259837 269834 280834 286834 291833 294825
      301817
 2.00 361765 360763 357762 354764 352766 351768 349769 347772
      346774 345778 347781 349780 352778 354776 355775 357772
      359770 360767 361765
 2.00 287825 285824 283825 282823 281823 279823 278825 277826
      276827 276828 275830 274830 275830 276830 278830 280828
      282828 282827 283825 285825 287825
 2.00 269826 267826 265827 267828 269827 269826
 2.00 266829 265827 263828 262829 264830 265829 266829

24HR QP VT 10/12Z
 0.01 485614 490617 495621 496629 497636 496644 495652 490667
      485680 482686 478692 469700 463709 458713 454718 451723
      448727 441730 438734 433739 438740 449745 455746 463744
      468740 471735 477726 481721 486719 493718 496719 500724
      499731 494744 487757 485764 482771 476782 471793 467805
      463817 459832 458840 457844 459845 461843 463840 465838
      468837 474839 478844 484853 484859 482862 481864 482869
      483876 481883 476894 469905 463906 460906 458903 455898
      457891 460885 459876 454873 447874 437876 423877 413874
      406871 401874 395874 389872 384868 381862 377857 369858
      363856 362855 361852 364846 366842 369836 368832 364834
      359837 356840 353842 351841 350837 349834 348829 344830
      337830 335830 334826 334819 338808 341801 339797 337795
      327805 319811 308816 295821 289823 282824 269830 260836
      250843 241848 234848 228847 224837 221820 220815 219806
      218798 220793 224781 227775 230772 240765 249758 257752
      266744 275735 284728 293719 309702 314699 319693
 0.01 467331 470331 472331 475330 477330 480330 482329 485328
      488328 490326 492326 494324 496323 498321 500319 502318
      505311 509297 512293 514285 518275 522264 522258 520253
      516243 512233 504227 500228 497232 495238 496244 488248
      481252 478255 475259 469268 463273 455277 448282 441287
      427297 419302 412305 410306 411309
 0.01 440320 439319 437318 435316 434316 432316 430315 429316
 0.01 416764 416761 414758 410761 408764 405769 403772 401776
      399780 396784 397787 399787 403785 406782 411779 413777
      415771 415767 416764
 0.25 467621 472624 476629 479641 480647 480654 479663 475671
      472678 468683 460694 450706 446712 444715 440717 434722
      430726 418735 409746 388765 377773 369776 362775 355771
      347774 341777 336781 325789 314798 303807 290813 275817
      261823 253826 246828 242827 240824 237818 238801 240795
      245789 257779 267772 278764 290756 313739 323730 334721
      353700 362690 372679 389656 396648 406641
 0.25 514266 515258 514253 512246 509244 508245 506260 502260
      496258 491257 486258 482260 478264 473274 470278 467281
      460288 453297 447304 444308 445313 450314 455314 460314
      464312 467308 470310 476313 480313 490312 494311 497307
      503299 509287 510275 514266
 0.25 475882 475880 475877 474875 473876 473878 473880 473882
      473883 475882 475882
 0.25 468870 469868 469865 469863 468861 467859 465859 464861
      463861 463864 462866 462869 462871 464873 465873 466875
      467873 467872 468870
 0.25 456801 455791 452789 449792 443801 438806 434806 430807
      427802 424802 420798 417803 417809 420816 423820 426822
      429828 434830 440831 445827 448823 453811 456801
 0.25 447863 445859 441860 434861 427861 421860 415859 413861
      414864 417868 424869 431869 437869 442867 447863
 0.50 456625 469628 470634 470639 469649 468658 465668 461675
      457681 445690 435702 430708 425713 418717 412722 405735
      400740 393745 379755 373758 366761 357762 351766 338775
      332779 324783 312790 306793 299798 293801 286805 281809
      273814 267817 261819 254823 245824 242822 241817 243808
      249794 253788 257784 282768 293758 298754 305750 314747
      319743 323736 329731 349711 368688 378676 387665 396653
      410644 418640 426640 435637 441635 455625
 0.50 505287 504278 502275 501271 497264 491260 485261 482262
      480266 479274 480279 482283 483286 485289 492294 499294
      502293 504289 505287
 1.00 496275 497273 496272 495270 495269 493268 491267 490268
      488269 487270 488270 489271 490273 492273 493274 494275
      495276 496275
 1.00 452651 451649 449647 445647 441645 437648 427653 423653
      419651 410656 400662 387676 375691 369699 363708 358715
      351722 336735 334739 336744 330751 323759 316766 314769
      312774 314780 320778 336768 368744 374737 381730 393715
      400708 404706 408702 424689 430680 434671 437666 440666
      444667 448663 450657 452651
 1.00 298779 294774 292772 289772 283775 277776 266784 261788
      259791 259795 262797 261801 256805 252809 248814 247817
      249819 253819 257818 267812 274809 280805 289797 293792
      296787 298779
 1.50 410681 407675 406672 403670 399672 396675 390681 379692
      370704 365712 362720 365726 362733 363738 366736 371729
      375723 377718 377716 378713 380714 379711 381708 387702
      393697 405685 410681
 1.50 336756 335754 333756 332756 331758 330759 332761 333759
      334758 335758 336756
 1.50 283796 283794 282794 280793 279794 277794 277795 276797
      275797 274799 274800 273801 272802 271804 272804 274804
      276803 278801 279800 281798 283796 283796
 1.50 277784 277782 275781 274782 273783 272783 270785 269786
      267788 265790 267790 269790 269789 271789 273788 274788
      276786 277784
 2.00 379702 377703 375704 374705 372706 370708 370709 369711
      368712 368713 367714 368716 370715 371714 372713 373712
      374710 376708 377705 378705 379703 379702

24HR QP VT 11/12Z
 0.01 556062 556056 556051 554042 549029 544017 537005 528994
      524989 520983 510973 508970 506965 504954 502947 500939
      495928 493919 492910 489902 486897 485894 482892 480889
      481884 483876 483864 486843 484834 484829 481821 478814
      471806 461799 454786 451780 448778 446778 443783 440790
      438794 437796 435794 438785 439781 440775 443767 445761
      449755 452750 453746 453739 455732 458726 463720 471709
      474704 479698 490687 495681 499672 500665 499654 497644
      495636 493632 487629 481629 474631 460636 448645 443646
      440645 431648 427654 425662 422677 419682 418688 415696
      417701 420709 423714 427719 432721 436720 438722 440726
      441730 439733 437734 436731 434728 431727 427731 422737
      419743 417750 412762 411765 413766 419763 421764 421769
      419776 416781 410783 405783 402785 399788 399792 401795
      404794 408793 412795 414798 414805 413808 413814 414819
      415823 417826 418824 420826 423831 424834 420836 417837
      416839 414842 415845 416851 418853 420860 424867 428883
      436899 445911 452921 453925 452929 454933 462940 466946
      469952 472959 476964 482979 485002 486006 488008 492008
      494005 494000 495995 496992 498995 500000 503006 512014
      515020 518028 518038 519046 523052 527058 531066 536073
      541079 545079 547078 550075 552069 556062
 0.01 517276 520262 521245 520236 512228 507229 503231 501235
      499249 496255 495262 491273 489280 487285 482292 477299
      470303 468303 467306 465310 466313 470315 474315 480316
      488319 494314 500309 506300 510292 515283 517276
 0.25 492669 492662 490657 487653 484648 478644 474643 471647
      466655 464658 464665 466670 469674 471680 473685 475687
      476682 476676 479678 486676 490673 492669
 0.25 453811 453808 453806 452804 450802 449802 448801 447802
      446804 446805 446807 446809 446812 446814 447815 449815
      451814 452812 453811
 0.25 444749 443747 439745 436748 435750 434754 433756 434761
      436763 439760 440757 442755 443752 444749
 0.25 430786 430783 430781 429780 427781 426781 425783 425784
      424785 423787 423788 422789 422792 421793 421794 421797
      422798 423797 424796 425795 425793 426792 427791 428790
      429788 430786


$$





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