Quantitative Precipitation Forecast
Issued by NWS

Home | 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
000
FXUS04 KWBC 092026
QPFPFD

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


PRELIM DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION
VALID DEC 10/0000 UTC THRU DEC 13/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR

DAY 1


...NORTHEAST...

SATELLITE WATER VAPOR LOOPS EARLY THIS AFTERNOON SHOW THE EASTERN
U.S. LONGWAVE TROUGH CONTINUING TO AMPLIFY, WITH THE NORTHERN
STREAM WAVE DROPPING INTO THE OH VALLEY WHILE THE SOUTHERN STREAM
VORT LOBE PIVOTS ACROSS THE SOUTHEAST. BOTH STREAMS HAVE A SURFACE
LOW REFLECTION -- ACROSS NORTHERN IN AND OFF THE MID ATLANTIC
COAST RESPECTIVELY. MILLER-B TYPE CYCLOGENESIS WILL BE UNDERWAY
EARLY IN THE PERIOD, AS BOTH AFOREMENTIONED STREAMS BEGIN TO
PHASE/CONSOLIDATE AND THE COASTAL LOW INTENSIFIES. FOR THE DAY 1
PERIOD, THE MODELS ARE CLUSTERED QUITE WELL IN TERMS OF THE TIMING
AND STRENGTH/DEPTH OF THE SYSTEM. MODEL QPFs ALSO GENERALLY AGREE,
THOUGH AGAIN FAVORED THE HIGHER-RESOLUTION GUIDANCE WITH RESPECT
TO THE TIGHTENING QPF GRADIENT ON THE WESTERN PERIPHERY OF THE
MID/UPPER LEVEL DEFORMATION AXIS -- OWING TO ROBUST LOW LEVEL
FRONTOGENESIS (ENHANCED WESTERLY FLOW AND THUS ACCELERATED DRYING
EAST OF THE MTNS ALONG THE WESTERN EDGE OF THE PCPN SHIELD) WITHIN
THE BROAD RIGHT ENTRANCE REGION OF THE ELONGATED N-S 180+ KT UPPER
LEVEL JET.

HEAVIEST ADDITIONAL LIQUID EQUIVALENT TOTALS (AVERAGING
0.25-0.50") AFTER 00Z SUN ARE EXPECTED ACROSS FAR EASTERN NEW
ENGLAND, I.E. EASTERN ME AND FAR EASTERN MA (CAPE COD). ELSEWHERE
TOWARD THE HUDSON VALLEY, AMOUNTS AVERAGING AROUND OR LESS THAN
0.10-0.25" ARE EXPECTED. FOR MORE DETAIL ON WINTER WEATHER..SEE
QPFHSD DISCUSSION.


...GREAT LAKES...OH VALLEY...CENTRAL AND SOUTHERN APPALACHIANS...

MODELS SHOW DECENT AGREEMENT WITH HANDLING OF THE AFOREMENTIONED
DIGGING S/WV TROF THAT DROPS S-SE FROM THE UPPER MIDWEST THROUGH
THE OH VALLEY/ERN TN VALLEY EARLY IN THE PERIOD. LAKE ENHANCED
SNOW SHOWERS WILL ACCOMPANY THE CLIPPER SYSTEM, WITH MORE PURE LES
TO FOLLOW PER THE ENSUING STRONG COLD ADVECTION. THE SNOW BANDS
ARE EXPECTED TO SPREAD INTO THE WESTERN SLOPES OF THE CNTL/SRN
APLCNS TONIGHT, AIDED BY THE INCREASING WLY/NWLY UPSLOPE FLOW.
PLEASE SEE QPFHSD DISCUSSION FOR FURTHER DETAILS ON SNOWFALL
AMOUNTS.

HURLEY/SULLIVAN

DAYS 2/3...


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

TWO WAVES OF LOW PRESSURE WILL SWING ACROSS THE
NORTH-CENTRAL/EASTER PORTION OF THE CONUS IN THE DAY 2/3
TIMEFRAME. THE FIRST IS A SHORTWAVE THAT MOVES ALONG THE EXISTING
UPPER TROUGH FROM LAKE SUPERIOR TO NEW ENGLAND SUNDAY NIGHT
THROUGH MONDAY MORNING AND THE SECOND IS A STRONGER SHORTWAVE THAT
AMPLIFIES THE UPPER TROUGH AS IT DIGS FROM NORTH DAKOTA SUNDAY
NIGHT...CROSSES THE MIDWEST LATE MONDAY...AND REACHES MAINE BY
LATE TUESDAY. THE SYSTEMS ARE ESSENTIALLY CLIPPERS WITH LIMITED
MOISTURE...PRECIPITABLE WATER VALUES RANGING FROM  0.25 INCHES TO
LESS THAN 0.5 INCHES. TEMPERATURES ARE LOW ENOUGH UNDER THIS
TROUGH FOR THE PRECIPITATION TYPE TO BE PREDOMINATELY SNOW.

12Z GUIDANCE DECREASED QPF COMPARED TO 00Z THOUGH MESOSCALE
PROCESSES WILL PRODUCE LOCALLY ENHANCED SNOWFALL. ALSO...LAKE
EFFECT/LAKE ENHANCED SNOW WILL DEVELOP IN PREFERRED LOCATIONS IN
THE LEE OF THE GREAT LAKES GIVEN THE GENERAL WEST TO NORTHWEST
FLOW.

WPC USED AN EQUAL BLEND OF THE 12Z GFS/ECMWF/UKMET FOR THE
STARTING POINT FOR THE QPF.


HURLEY/JACKSON


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

24HR QP VT 11/00Z
 0.01 484615 492616 496620 500629 502632 502638 502647 501653
      499662 497668 494674 490681 487686 486689 486693 491698
      493702 494708 491718 487724 480726 473726 467722 462718
      460718 459721 458725 458729 459734 458738 455745 445756
      444760 446763 449760 453759 456759 458761 462767 464777
      465782 464787 462792 462797 463802 464813 464823 470823
      474830 474836 474841 476842 481847 485854 488864 491871
      491876 490881 487888 485895 482902 478909 475912 473913
      469915 470910 468906 465908 463908 462905 461900 461891
      464885 463878 461874 457870 450865 443865 432868 417868
      411865 405861 400856 395851 392847 389842 386834 384831
      382832 377837 373842 367851 364850 363847 366838 363835
      360837 355841 349847 347844 347839 350833 354825 361816
      366811 371808 381798 392789 398786 404786 411784 415779
      418776 422774 426773 428769 428749 428743 425742 420745
      409752 397759 383762 374763 368757 363752 360750 356750
      353750 350752 343755 341757 337759 330763 326762 319763
      312762 304764 273773 244783 240784 237784 235783 233775
      230767 231763 233761 252746 262738 275729 297713 309705
      314701 322696 333690 345684 359676 373667 396653 404646
      413639
 0.01 522264 521255 518249 512234 507229 500227 497233 497239
      497243 487249 481252 476258 468269 458279 449287 444291
      438294 433298 429302 424307 425310 429311 433312 436311
      441310 448308 454305 458302 464300 476297 488301 491301
      495302 500301 503299 505296 509291 513284 517277 520270
      522264
 0.01 521010 520999 517991 513983 510978 501967 496962 492962
      489959 481959 477959 476962 472979 475989 480994 490005
      498018 502023 507027 511027 514025 518020 521010
 0.01 450736 449733 448731 446732 445731 443731 441731 439732
      438732 436734 435735 433736 432737 433739 435739 437738
      438738 440738 442738 444738 445738 447738 449737 450736
 0.01 446783 446780 446778 446776 445773 444771 442770 441772
      441774 441775 440777 440779 440782 440784 441786 443786
      445785 446783 446783
 0.01 443839 443836 443834 442833 440833 438833 436833 435833
      433835 434838 434840 434842 434845 434847 436849 437849
      438849 439849 441846 442844 442841 443839
 0.01 440789 438784 436783 433785 431788 430790 429793 428796
      428800 428805 429807 432807 434804 435801 437799 437796
      438791 440789
 0.01 433739 431738 430738 428739 427741 428743 430742 432741
      433739
 0.01 430826 427824 427821 426817 423816 418823 415828 410833
      408837 407843 408848 411851 414852 417851 421850 423850
      425848 428841 427829 430826
 0.01 408810 407808 406808 405807 403807 401809 400811 402813
      403813 405812 407812 408810
 0.01 260823 258819 255817 251815 247813 244812 240811 236812
      237816 241819 244821 246823 250825 256825 260823
 0.25 474619 490634 492638 492644 491651 488657 484664 477676
      470684 465688 459691 449695 444696 441698 437703 431706
      425707 418707 410708 404708 399707 386703 377707 354721
      342727 328731 304740 255761 252761 249758 252752 261746
      284733 305721 328707 350694 361688 374681 385674 391670
      394666 404657 414650 425642 430638 435632
 0.25 514266 515261 515256 514253 513250 513247 511244 508243
      507243 505247 505252 505255 505260 505265 507267 509267
      510268 512268 514266
 0.25 503275 504271 504265 500261 494258 489258 484259 480262
      477268 476273 477276 483279 488279 493279 498279 503275
 0.25 467861 467858 467857 465856 464858 465861 465863 465864
      466863 467861 467861
 0.25 449807 449804 448803 446803 445805 443807 443808 442809
      440810 440811 440813 440814 442815 444815 445813 446812
      447810 448809 448808 449807
 0.25 428786 426784 425784 423787 422789 421793 420797 420799
      420804 422804 424801 425798 426796 426793 428788 428786
 0.25 389801 389799 388797 386798 385799 384800 383801 382802
      381804 381805 380807 380808 382809 383807 385806 387805
      388804 388803 389801
 0.50 497276 499271 498268 497265 494262 492261 489260 487260
      485261 482262 480264 481269 482271 485273 489274 492275
      495276 497276
 0.50 484646 484641 482639 478636 471633 465629 461626 456625
      450628 444631 437636 429643 421649 413655 406660 399666
      392674 388677 383681 376685 358696 341704 322715 314720
      311724 310728 315728 319726 328721 337716 345712 368705
      386697 407689 442672 447673 453672 461671 466670 469669
      471665 470662 473663 475660 478656 484646
 0.50 425794 425791 424791 425794 425794
 1.00 441648 436648 430651 424652 420655 412662 404669 396676
      393680 393683 396683 406678 414672 421665 429656 433653
      437650 441648

24HR QP VT 12/00Z
 0.01 537051 538035 535022 529997 525985 522978 520970 520962
      518955 516947 515941 512929 509918 503910 500906 496903
      497892 499875 499858 497855 497849 496842 494835 491831
      486826 473810 466801 461797 457796 449792 445790 444788
      441781 441773 442767 444757 447752 450749 455749 459747
      462743 463737 464730 464722 467717 469716 470712 468706
      466695 464680 461682 459686 450706 446711 441715 440720
      437724 432728 433737 428748 424757 421768 411785 388794
      386796 385800 387805 388808 391809 394805 398802 400797
      403793 406793 407796 405806 404814 399813 395814 394816
      393824 394833 396840 400851 405860 407879 415901 419911
      426919 432931 436945 455981 459981 461978 464977 469981
      472987 473989 472993 467990 464990 463992 463999 472018
      474022 479025 487030 498035 507041 514049 517046 521049
      529053 535053 537051
 0.01 499277 500272 500268 497262 493258 488253 484250 479245
      473244 469245 464247 460251 451258 447262 445266 451269
      458270 463270 470272 483277 488277 495279 499277
 0.01 501700 498690 495684 491675 487668 484667 482670 478671
      475670 472673 471678 472688 476694 479695 483693 489696
      494701 496703 501701 501700
 0.01 505026 502021 499016 496010 493008 490008 485007 482005
      479007 483011 488013 491014 493016 498020 501024 505026
 0.01 462648 459646 454648 445654 436660 426666 422669 418672
      407678 401685 395694 390703 387708 386710 386714 391724
      402726 406728 409725 413720 416715 421707 428699 435692
      441682 442676 445673 453665 457656 459651 462648
 0.01 457005 457003 456003 455000 455998 455997 454996 453995
      451995 450994 448994 446994 445995 444995 444997 445998
      446000 446001 448001 450001 451003 453004 454005 455006
      456006 457005
 0.25 436890 436887 436885 435885 434883 434882 433883 432884
      432885 432888 433890 434891 436891 436890
 0.25 433866 431864 429863 428863 426864 425864 425867 426869
      428871 430872 431871 432871 433869 433867 433866
 0.25 418695 417691 415689 409690 404693 401697 397703 396710
      400715 406716 410711 413706 416700 418695
 0.25 423794 423791 421792 420794 419794 419797 420799 422797
      422796 423795 423794

24HR QP VT 13/00Z
 0.01 513291 507283 502278 494273 488267 480252 477250 473249
      467252 460256 453258 447258 448253 451250 453247 457245
      463241 466239 470239 478242 485239 489240 493243 497250
      505253 513255 521258 524260
 0.01 474619 479628 484638 494661 497672 502681 503693 502698
      503704 504712 503718 499728 495738 491749 486765 484771
      482776 483791 488801 489806 490814 490823 489830 486841
      480881 470897 467902 463903 462903 461898 461889 459877
      457874 452872 433874 430876 424877 418882 414879 411875
      407871 405866 403862 402857 399848 396839 392831 389827
      384825 381825 380827 375828 370827 365829 359837 354838
      353835 356828 359820 366815 373809 378801 385793 388790
      392786 395784 396779 396774 394769 393763 390759 389755
      388749 390746 391739 392728 391720 387717 382716 378720
      373725 368728 365728 361733 354738 351740 345742 340737
      342726 346715 349709 353704 360686 368680 372678 376676
      386670 396664 407655 413648 421644 433638 438631
 0.01 290062 291058 289058 287060 285062 283064 282065 280067
      278070 277073 277078 279078 281076 283074 284072 286070
      288067 289064 290062
 0.25 460736 459733 457732 455734 454737 452738 446739 443738
      441734 441730 444726 447722 446718 446710 448705 452698
      448687 447684 448678 450672 450667 447664 443665 439663
      435662 431665 428669 422678 421682 421687 423692 423697
      419707 418713 419718 422721 422725 421735 420746 419752
      419756 419760 422762 422766 418776 412782 409786 408793
      411805 414814 416816 420814 425812 430812 435818 441822
      449827 453829 455828 456824 459817 464807 464801 462796
      461787 462781 462774 461768 460763 456759 455752 455744
      457739 460736
 0.25 392796 391795 390796 388797 390797 391797 392796
 0.50 432740 432737 432735 431733 430733 429733 427732 426734
      427736 427738 428740 429740 430741 432740 432740

$$





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