Quantitative Precipitation Forecast
Issued by NWS

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS04 KWBC 082107
QPFPFD

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


FINAL DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION
VALID DEC 09/0000 UTC THRU DEC 12/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

FOR THE 00Z QPF ISSUANCE...MINOR CHANGES WERE MADE TO THE 00Z-06Z
TIME FRAME BASED ON RADAR TRENDS AND THE MOST RECENT HRRR AND 12Z
HREF MEAN.

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

THE EJECTION OF AN INITIAL POSITIVELY-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 FRIDAY NIGHT. THE UNSEASONABLY LOW LATITUDE
HEIGHT ANOMALIES ASSOCD WITH THE UPPER TROF (4-4.5 STANDARD
DEVIATIONS BELOW NORMAL OVER SOUTH TX AND THE WESTERN GULF COAST)
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.

THE HEAVIER QPF AXIS OF PCPN NORTH OF THE FRONTAL BOUNDARY IS
EXPECTED TO SHIFT FROM THE SOUTHEAST AND SOUTHERN APPALACHIANS
INTO THE MID ATLANTIC REGION AND EVENTUALLY COASTAL NEW ENGLAND.
THIS AS THE BROAD SCALE FORCING AHEAD OF THE AMPLIFYING UPPER
TROUGH GETS A SIGNIFICANT BOOST FROM THE STRENGTHENING
RIGHT-ENTRANCE REGION UPPER JET FORCING. THE ENSUING UPTICK IN
FRONTOGENESIS AND ATTENDANT ISALLOBARIC NW-W COMPONENT TO THE FLOW
AT LOW LEVELS WILL ULTIMATELY LEAD TO A TIGHTENING NW-SE QPF
GRADIENT, PARTICULARLY WEST OF I-95, WHICH COULD BECOME BUOYED
SOMEWHAT PER WHAT WOULD BE A DOWNSLOPE COMPONENT. IT SHOULD BE
NOTED THAT SOME OF THE HIGH-RES GUIDANCE DEPICTS THIS IDEA (I.E.
DRIER COMPARED TO THE NON-CAM GUIDANCE CONSENSUS), HOWEVER DESPITE
THIS THE HIGH-RES CAMS HAVE TRENDED WETTER ALONG THE THE I-95
CORRIDOR COMPARED TO THE PREVIOUS RUNS. THEREFORE, OVERALL, A
CONSENSUS APPROACH TO THE QPF WAS UTILIZED, LEAD BY THE 12Z ECMWF
AND GFS, ALONG WITH THE 15Z NBM AND LATEST WPC BIAS CORRECTED
ENSEMBLE QPF.

ACROSS FL...WITH THE 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 HAVE CONVERGED
WITH THE CLIPPER SYSTEM ROUNDING AND AMPLIFYING THE LONGWAVE
TROUGH BASE FROM THE UPPER MS VALLEY AND UPPER GREAT LAKES
EASTWARD ACROSS THE OH VALLEY ON SAT, BEFORE THIS WAVE PHASES WITH
THE SOUTHERN STREAM AND RESULTS IN MORE RAPID COASTAL
CYCLOGENESIS. PRIOR TO THE PHASING, ACCOMPANYING THIS FEATURE WILL
BE MAINLY LIGHT TO SPOTTY MODERATE LAKE ENHANCED SNOWFALL DOWNWIND
OF LAKES SUPERIOR AND MICHIGAN -- AS THE COMPACT AREA OF WAA/MOIST
ISENTROPIC ASCENT ABOVE THE LAKE-INDUCED CBL COMBINES WITH THE
RESIDUAL OVER-WATER INSTABILITY. BEHIND IT, MORE GENERAL ("PURE")
LAKE EFFECT SNOWS WILL ENSUE FROM WEST TO EAST AS VERY STRONG 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 ON
SAT. 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...

THE SOUTHERN STREAM TROUGH MOVING THROUGH THE DEEP SOUTH/GULF OF
MEXICO TODAY, RESULTING IN EARLY SEASON SNOW FOR PARTS OF THE
COUNTRY NOT ACCUSTOMED TO WINTRY PRECIPITATION, WILL PHASE WITH
NORTHERN STREAM UPPER DYNAMICS OFF THE MID-ATL/NERN SEABOARD LATE
SAT INTO SUN. THE ELONGATED AREA OF SURFACE LOW PRESSURE OFFSHORE
WILL BECOME CONSOLIDATED, DEEPEN AND LIFT NORTH INTO NOVA
SCOTIA/CANADIAN MARITIMES. THE POST-FRONTAL DEFORMATION ZONE WILL
BRUSH PARTS/EASTERN NEW ENGLAND WILL HEAVIER QPF. FOR THE MOST
PART, GUIDANCE IS RATHER SIMILAR ON THE PROGRESSION OF THIS SYSTEM
AND QPF AMOUNTS, SUGGESTING POSSIBLE .25 TO .75 INCH AMOUNTS FROM
EASTERN MA UP THROUGH MAINE AND PARTS OF NH AND WPC FOLLOWED THIS
ROUTE.

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

IN THE WAKE OF THE PHASED STORM SYSTEM OFFSHORE OF THE NERN QUAD
OF THE COUNTRY, DEEP COLD CYCLONIC FLOW ACROSS THE WARM AND
UNFROZEN GREAT LAKES WILL LEAD TO HEAVY LAKE EFFECT SNOW LATE SAT
THROUGH SUN. THE GLOBAL MODELS AND ESPECIALLY THE HI-RES MODEL
GUIDANCE ARE PINPOINTING THE TRAJECTORY OF THESE INTENSE SNOW
BANDS VARIOUSLY, WEST TO EAST ACROSS LAKE SUPERIOR FROM THE
KEWEENAW PENINSULA TO NERN UP OF MI, SERLY OFF LAKE MICHIGAN IN A
COUPLE SPOTS INTO LOWER MI, AND PREDOMINANTLY SWRLY COMPONENT OFF
LAKES ERIE AND ONTARIO IMPACTING NWRN PA INTO SWRN NY STATE AND
INTO UPSTATE NY. FINALLY THE CYCLONIC FLOW WITH NWRLY WINDS INTO
THE APPALACHIANS COULD SPELL FAVORABLE OROGRAPHICS FOR HEAVY
SNOWFALL FROM SOUTH CENTRAL PA TO WESTERN NC.

THEN ON SUN EVENING THROUGH MON, A TRUE ARCTIC CLIPPER FEATURE
WILL DIG THROUGH THE UPPER MS VALLEY INTO THE GREAT LAKES/OH
VALLEY. EXPECT SIMILAR EFFECTS FROM SUCH A SYSTEM, RELATIVELY DEEP
SURFACE LOW, GUSTY WINDS, STRONG COLD ADVECTION AND MOSTLY
MOISTURE STARVED. THE AGREEABLE GLOBAL MODELS SUGGEST A
STREAK/AXIS OF HEAVIER SNOW FROM NORTHERN MN THROUGH WI INTO MI,
GENERALLY A .25 INCH OR LESS QPF AMOUNTS. BEFORE THE SYSTEM
ARRIVES, CONTINUED LAKE EFFECT AND PERHAPS SOME LAKE ENHANCEMENT
IS EXPECTED DOWNWIND OF THE EASTERN LAKES.

HURLEY/MUSHER


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

24HR QP VT 10/00Z
 0.01 459624 466642 468648 467652 465662 460680 458689 456697
      448713 444719 440727 435737 430743 418756 395780 386793
      378805 375810 375814 385813 390812 394813 401814 406814
      411813 419808 423806 425801 426792 428787 430784 432782
      433785 431790 430795 434794 436789 437770 439761 444752
      447751 449753 447755 449757 454752 457748 458744 464735
      467727 469715 471709 474706 489708 497711 501717 505726
      507739 506750 504758 504762 501765 496766 493765 485764
      479769 473788 469797 467802 466805 466809 466821 466826
      466832 470842 474851 479857 483865 483878 483882 481886
      479891 477895 476898 476902 473907 468914 462920 457925
      453931 447935 438935 435933 434927 431924 428924 422919
      418909 407896 396889 393887 390883 389880 384879 376876
      372873 370869 368859 358860 355861 351860 354854 357850
      360849 365843 374828 375823 374820 372820 368822 366825
      359839 354846 347853 335864 324874 320879 313886 304896
      291907 279917 270919 265918 260913 259911 259904 260895
      261891 261885 259880 256878 251873 244868 237862 235858
      232856 226854 223844 222836 222826 220815 219795 220785
      220780 221778 239769 255761 261757 268754 297737 310727
      319717 326710 332704 343693 354681 366669 371663 375659
      379653 384648
 0.01 483338 484336 485336 486334 487333 488332 489331 489330
      490328 491328 493326 495325 495324 497323 497322 499321
      499320 501319 502318 505311 508299 512292 514280
      514274 513270 509262 507260 503259 499258 496258 489259
      484260 478264 472267 467271 455277 450280 445285 433293
      422300 411305 406308
 0.25 436632 447642 448649 449655 449664 447675 445684 442693
      439699 430714 421726 410739 405745 401752 393766 389773
      385778 377792 372800 367806 358818 349829 342834 340830
      338827 333824 327827 314836 301842 287852 275859 270861
      266861 261862 256860 242856 232846 230843 229838 227830
      226809 228802 229794 231790 235788 242785 256777 270770
      283763 297753 310744 321734 332725 344713 354701 372677
      381665 392652 405642
 0.25 503299 505293 507287 506281 504276 497272 493271 489272
      483275 477279 471283 464285 453298 448301 445302 442306
      440310 441313 447319 464324 473326 480326 486322 492318
      495316 497312 501304 503299
 0.25 470878 469875 468873 467871 466868 466866 465864 464864
      463866 462868 462869 462871 462873 462874 464875 464876
      466878 466879 467880 468881 469880 470878
 0.25 469893 469890 468889 467890 466892 466893 465895 465897
      465898 464900 464903 465904 466903 467900 467898 468895
      468894 469893
 0.25 456832 455823 454821 454816 453806 452796 451793 449794
      446802 443806 440810 439815 440820 441822 444823 449821
      453823 455833 456832
 0.25 454869 455861 453855 449852 444854 439855 434853 430850
      427850 419858 415860 409861 409866 412870 415872 421874
      431874 440874 444877 446878 449877 452874 454869
 0.25 441829 440827 439827 438827 436827 436828 436830 438832
      440831 441829
 0.50 503291 504286 504283 503280 500278 497278 495278 491278
      489278 488283 488288 489290 491292 494294 497294 499294
      501293 503291
 0.50 495307 496302 495299 491297 486297 481300 477303 473305
      471309 471314 478317 483316 487314 492312 495307
 0.50 463311 462309 462308 460307 459307 458307 457307 455308
      454308 455309 455311 456312 457312 458311 459312 461312
      463311
 0.50 439653 436647 430642 423641 416642 408646 402652 392662
      354709 344720 334730 310749 287766 277774 268779 261782
      248789 242793 238797 233803 231811 231819 231830 232839
      237845 243849 248851 253852 256854 263858 268857 276853
      288845 299838 306833 311827 316822 321818 344801 355792
      360791 365790 372786 381774 389762 397747 404734 419709
      426696 434679 438667 439660 439653
 0.50 447865 445864 443865 442865 440865 438866 437868 438868
      440869 442868 443868 445868 447865 447865
 0.50 417865 415865 414865 413866 414866 416867 417865
 1.00 430661 429655 428653 425651 422651 416653 411657 401667
      391678 374697 355717 336735 327744 314752 276788 270790
      265794 259799 256803 251808 246811 241816 239822 239830
      238835 240840 244843 252844 260843 266845 269846 272845
      281842 290834 300826 310817 322810 329800 337789 341783
      347779 352775 359773 372767 378764 382759 389748 396735
      409711 421685 427673 429667 430661
 1.50 423665 423658 418659 411664 397681 385695 371709 356723
      341735 327749 314764 307770 304773 302777 303782 302785
      295792 292796 292798 295798 299798 303797 312792 320786
      327779 333774 342766 350760 358756 365750 370747 374748
      376751 378751 381748 391732 396724 401713 410695 414686
      420676 422670 423665
 1.50 309812 308811 306811 305812 306813 308812 309812
 1.50 302815 300810 298808 294807 294805 290807 286814 272816
      269814 271811 269809 264809 260810 254814 248818 246821
      246825 247834 248837 253837 260834 266831 274828 278830
      280832 283834 285832 291828 296823 300817 302815
 1.50 289803 287804 286804 287805 289804 289803
 2.00 413675 412671 410671 406674 399685 392695 385703 378712
      376714 378714 383710 388709 390711 390716 393717 395715
      398709 404699 409686 413675
 2.00 363733 361731 358732 350735 344739 339744 329754 321765
      314777 310784 313784 316781 321778 326773 338763 347754
      352747 357741 362738 363733
 2.00 266827 267825 265823 264823 263823 261824 259825 258827
      256828 254830 254831 254832 255832 256833 258832 260832
      260831 262831 264830 265829 265828 266827

24HR QP VT 11/00Z
 0.01 485614 489616 492619 495621 496626 497637 496647 493656
      494662 494670 495681 496686 494690 491695 485700 480702
      476704 458729 459734 458741 455747 452750 448752 445759
      442767 441775 440783 443785 445783 450778 455772 460765
      464764 467765 470767 472770 473778 470784 466790 463795
      462799 467806 472811 475818 477825 478836 480845 483852
      484858 482862 481868 481875 476892 474900 471902 469900
      468902 465905 463906 462903 462898 461894 459891 462888
      464877 460871 457864 455861 452863 445863 440866 432868
      427869 417868 414866 411863 401855 399848 397844 393842
      382834 384827 380826 378830 378834 375835 368839 361845
      364838 365830 363829 361832 358839 352844 349847 348844
      350838 348837 350834 358819 363814 368811 372806 376802
      380800 382798 387792 400786 406782 411779 425773 428767
      423763 424758 424751 417753 414755 410757 408759 404760
      393767 384777 364755 360750 356750 352749 342757 334761
      329766 319776 311786 306791 302789 290779 286775 280772
      271775 262777 256780 248782 239784 235783 234780 232772
      230767 231763 251747 262738 275729 287721 297713 304709
      310704 316700 323697 332686 342679 371665 401651 407649
      411646 419638
 0.01 556062 556052 555047 552038 545018 537998 533989 528982
      523974 517968 512961 505956 498951 496947 493945 486942
      482939 479939 482949 486957 485959 481958 474954 470955
      472960 477965 480967 485969 491975 503986 507990 510994
      511999 510006 502010 498016 498022 499026 506032 516046
      523053 528060 533068 537075 541079 545079 548077 550074
      553066 556062
 0.01 522264 521254 521244 520238 518235 512228 500228 497232
      497239 497243 495245 488248 483251 477256 473262 468270
      463274 452284 442293 435296 429301 425307 424309 428311
      432312 436311 442309 449307 454305 461301 467299 471298
      473299 473301 468304 465308 466313 473316 476315 480317
      488319 499311 507297 512289 516280 519272 522264
 0.01 491934 491932 489929 486927 484926 482924 479924 477922
      475922 477924 479927 480929 482932 484932 486935 489935
      491934
 0.01 452735 451733 450731 448732 447733 445734 445735 444737
      445738 447738 449738 451738 452735
 0.01 445836 444831 443829 440830 438832 437835 437840 436842
      436847 436852 438854 439851 440849 442846 442844 443839
      445836
 0.01 434833 433827 429827 425827 422825 419824 417828 412833
      409840 407843 404843 402844 401847 402850 405853 408852
      410849 413852 416852 418849 425848 428840 433835 434833
 0.01 260823 257819 252816 249812 245809 241805 239803 235803
      233808 236813 240817 243821 248824 250825 254825 260823
 0.25 468621 473626 477633 483648 488668 487673 485677 480682
      474687 469693 465698 460701 450706 442707 435709 430709
      426711 422712 419711 415705 412698 412695 410694 405694
      400700 395704 389709 384714 374722 367725 358726 349727
      341730 331732 325735 313741 301747 287754 263768 256772
      249774 241776 238775 237771 240765 244760 253752 265745
      277737 291730 303723 316716 322713 326708 337699 347691
      360683 375676 388669 399662 412653 423644 442630
 0.25 515267 516258 515251 512245 510242 507243 504255 503257
      500258 494258 489258 484259 480262 477268 477276 483279
      488279 491284 493290 498292 503290 507287 510281 513274
      515267
 0.25 472855 471853 471848 470843 469840 468839 466841 466844
      465849 465853 465858 467861 469863 471863 472858 472855
 0.25 456806 455801 453796 450795 448797 446800 443805 441808
      440813 440816 442817 447817 449819 454820 455813 455807
      456806
 0.25 447712 447710 445708 444709 443711 442712 441713 441716
      443716 444716 445715 446714 447712
 0.25 437758 437757 436756 435755 433754 432756 432759 433761
      433763 434765 436764 436763 437760 437758
 0.25 431781 430778 429778 428779 427780 427781 426784 426785
      425786 425789 424791 423794 424796 425797 426796 427795
      427793 428791 429791 429788 430786 430783 431781 431781
 0.25 423862 422862 421861 419862 419863 421864 422863 423862
 0.25 389799 388797 386798 384798 383800 381802 380805 382806
      383805 385804 387803 388801 389799
 0.25 358834 358832 357830 356830 356832 355835 357836 358834
 0.50 459624 466627 469627 471632 474636 474644 478650 478661
      478666 476669 470673 458677 452680 446679 433686 422695
      421690 422686 425679 426672 424667 421667 400685 389695
      380702 373707 367711 353716 339722 327727 313734 302740
      278755 265762 259765 252767 250762 252759 257754 266748
      292735 317722 324719 330714 340707 363691 387675 399667
      410659 421651 434644 443634 452626
 0.50 501275 500269 498266 494262 491260 487260 484261 480264
      481270 485273 490275 495277 499276 501275
 0.50 434761 434759 434758 434759 434761 434761
 0.50 428788 429786 427784 427786 426789 428789 428788
 1.00 461644 461639 459634 458631 455633 454635 453639 451642
      451644 450647 450652 453653 456651 458649 460646 461644

24HR QP VT 12/00Z
 0.01 543041 543029 543023 542019 542014 540010 537002 531988
      524977 512957 507952 504945 502939 499934 494921 489914
      485907 482889 480882 481874 479856 476842 469833 463821
      456808 447797 441781 441771 442764 446752 448744 449741
      449737 464720 471707 474699 475695 475690 473673 470674
      467682 453703 444709 440715 440721 430728 429731 430733
      433734 433738 431740 430744 429747 426748 420745 418750
      410757 406761 404766 403783 403786 400789 395792 389796
      385801 388806 393810 396814 400820 399829 400840 400850
      404854 407857 412859 407867 409871 409875 406882 407887
      413884 419900 422907 426912 429917 431921 431926 431932
      433935 435940 440941 443947 446950 448953 444954 448964
      452979 457986 460993 458998 456999 452998 450995 446992
      443987 439982 434977 425974 424976 425979 429983 433986
      432995 435000 439002 443000 444998 446001 449007 461013
      459016 459020 463024 465040 469041 471039 474039 475037
      477039 480047 482048 484045 489040 492042 494039 494035
      491027 489025 490021 490015 489012 490009 494008 495012
      496021 499029 505039 507043 511048 515053 521055 530056
      535054 539049 543041
 0.01 470986 470984 469982 467981 465979 464979 463979 462977
      460979 460981 462983 464984 465984 467986 469988 470986
 0.01 422699 421694 419691 415692 410697 408704 406712 404718
      401725 403734 405743 404750 406753 409752 413746 416740
      421736 424730 420728 415729 414726 417725 418712 420703
      422699
 0.25 531021 530015 528010 524002 519994 513986 508980 504978
      501977 502984 504988 509996 515004 519011 524018 527022
      529023 531021
 0.25 440755 440753 440752 438751 437753 436753 436756 435757
      435758 435761 435763 436764 438764 439762 439761 440760
      440757 440755 440755
 0.25 437866 436864 434863 433861 431861 430862 430864 431866
      431867 433868 434868 435869 436868 437866
 0.25 427791 427788 427786 426784 424785 423787 422788 422789
      421792 420794 420797 420799 420801 422802 423801 424801
      425798 426796 426793 426792 427791
 0.50 425794 425791 424790 424791 424794 425794 425794

$$




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.