Quantitative Precipitation Forecast
Issued by NWS

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102
FXUS04 KWBC 170658
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
157 AM EST FRI NOV 17 2017


PRELIM DAY 1 QPF DISCUSSION
VALID NOV 17/1200 UTC THRU NOV 18/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

...WESTERN U.S...

A POSITIVELY TILTED LONGWAVE TROUGH WILL TAKE ON A MORE
PROGRESSIVE EASTWARD TRACK FRIDAY AND FRIDAY NIGHT, REACHING THE
PLAINS BY 12Z SATURDAY, AS IT MOVES THROUGH A MORE
COMPRESSED/ZONAL UPPER FLOW PATTERN. THE 500 MB REFLECTION IS NOT
OVERLY ANOMALOUS...BUT THE UPPER JET STRUCTURE IS SEASONABLY
STRONG. BEHIND THIS SWIFT MOVING TROUGH, THE ENSUING DEEP-LAYER
RIDGING IN ITS WAKE WILL LEAD TO A QUICK DISSIPATION OF THE
ATMOSPHERIC RIVER AS IT PUSHES FARTHER SOUTHWARD INTO SOUTHERN CA.

THE STRONG 850-700 MB FLOW ASSOCIATED WITH THE WARM CONVEYOR BELT
(ELONGATED INITIALLY, BECOMING MORE COMPACT WITH TIME), ALONG WITH
THE ROBUST FRONTOGENETICAL COMPONENT PER THE VIGOROUS VERTICAL
SHEAR, WILL MAKE FOR MODERATE-HEAVY OROGRAPHICALLY AIDED PCPN
TOTALS ACROSS THE UINTAS/WASATCH MTNS IN UT AS WELL AS THE
CENTRAL-SOUTHERN ROCKIES IN CO AND NORTHERN NM. GIVEN THE FAIRLY
GOOD MASS FIELD CONSENSUS AMONG THE LARGER SCALE MODELS, WPC WAS
AGAIN ABLE TO UTILIZE AN ENSEMBLE OF HIGH-RES GUIDANCE WITH THE
QPF, WHICH WERE OF PARTICULAR VALUE OVER THE N-S RANGES GIVEN THE
DEEP ORTHOGONAL FLOW. NEVERTHELESS, GIVEN LARGE-SCALE SYNOPTIC AND
FRONTAL FORCING, ALONG WITH THE HIGHLY-ANOMALOUS 850-700 MB
MOISTURE FLUX (4-4.5 STANDARD DEVIATIONS ABOVE NORMAL), WPC
REMAINED RATHER GENEROUS WITH THE COVERAGE OF LIGHTER AMOUNTS OVER
PORTIONS OF THE GREAT BASIN, WITH THE PRESUMPTION THAT THE
AFOREMENTIONED FAVORABLE SYNOPTIC SCALE AND MOISTURE PARAMETERS
WILL LIMIT THE PCPN SHADOWING SOMEWHAT.

...EASTERN / NORTHERN U.S...

AHEAD OF THE WESTERN U.S. TROUGH...WARM ADVECTION AND UPGLIDE ON
THE 295K ISENTROPIC SURFACE WILL CONTRIBUTE TO A LIGHT
PRECIPITATION SWATH ACROSS THE FAR UPPER MIDWEST AND GREAT LAKES.
THE WRF-NMM...WRF-ARW...AND NATIONAL BLEND OF MODELS DEPICTED QPF
THAT WAS CONSISTENT WITH THE SHAPE OF THE ECMWF ENSEMBLE AND ALSO
SREF QPF PROBABILITY FIELDS. THIS WAS ALSO SIMILAR TO WPC
CONTINUITY...JUST SLIGHTLY HEAVIER FOR THE ARROWHEAD OF MINNESOTA.

FARTHER EAST...A COASTAL LOW IS FORECAST TO FORM AND QUICKLY TRACK
NORTHEASTWARD ACROSS NEW ENGLAND...BRINGING BOTH RAIN AND
SNOW...WITH THE ACCUMULATING SNOW CONFINED TO NORTHERN REACHES OF
VT/NH/ME. TRENDS SEEMED TO FAVOR A MOVE TOWARD THE NCEP
GUIDANCE...AND THE LATEST 12Z ECMWF SEEMS TO SUPPORT THIS MOVE.
WPC QPF BLENDED TOWARD THE WRF-ARW AND NAM...ALTHOUGH THE NAM WAS
LIKELY TOO STRONG IN MAGNITUDE...SO ITS INFLUENCE WAS TEMPERED.
OVERALL THE SYSTEM HAS TRENDED SOMEWHAT FASTER...SO THAT THE NET
RESULT IS A QUARTER TO HALF INCH LESS PRECIPITATION EXPECTED OVER
DOWN EAST MAINE COMPARED TO EARLIER FORECASTS...BUT STILL WITH
WIDESPREAD TOTALS APPROACHING A HALF INCH OF LIQUID.

HURLEY


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

24HR QP VT 18/12Z
 0.01 521269 523262 523256 521249 516244 513237 499210 485203
      479203 473205 467208 460210 456212 449213 442213 437213
      435214 425220 428228 434232 436238 434247 438251 442250
      446251 452250 457249 464247 468248 470251 478264 482270
      486277 487284 490291 495298 501302 506300 510294 514288
      517280 521269
 0.01 532195 533185 530178 525169 511154 497142 492134 485126
      478121 472120 469119 467117 471108 468102 466096 466092
      467090 468076 467055 467036 466030 466021 466013 465008
      460998 459996 456995 451995 447005 445010 441013 436007
      433004 430000 426989 423979 426968 428964 428959 430954
      430947 430941 431937 432932 436931 443931 446932 448934
      454942 457947 461947 468940 474932 480923 484915 489908
      498892 502885 503878 505875 508864 510857 511851 512846
      512838 512833 514830 517825 521819 523814 524807 523791
      516784 509778 506775 504767 500757 496750 494746 490746
      479748 477747 474750 470758 466761 461763 457765 451767
      438762 433761 428763 423766 417768 406770 400779 390796
      388799 386802 386805 385816 382836 380846 377855 371873
      367883 365887 364892 365898 365904 363911 359912 355909
      355902 354896 353894 350894 345895 344900 346910 346915
      343918 337926 334934 333940 334946 334953 335958 336960
      338960 344961 347959 350955 354949 366943 370930 372925
      376922 380925 380933 382939 379944 371949 370949 369954
      370960 373963 378963 383963 386961 388963 389966 389972
      389979 390984 390993 389001 388006 388012 389022 389034
      385044 384047 379048 373047 367047 360048 356051 354056
      356062 358067 361071 364075 366080 366085 363088 359089
      356091 354095 356098 362100 364103 369109 372110 372113
      370117 362117 359118 358121 360126 364129 369131 372134
      373138 379142 386151 389155 388164 388170 390176 392179
      397179 400176 403175 405177 404183 402189 397196 393197
      388195 381190 375182 371179 367177 357178 350181 346189
      345192 345196 347203 361206 366208 367207 363203 363199
      364197 366195 369196 373199 386210 390214 395217 399219
      405220 408218 411215 416208 418204 418199 412193 411186
      415182 421178 425170 427158 428150 427145 426134
 0.01 426134 427129 429127 433124 437123 442124 443128 442130
      438134 435138 434145 433155 436159 438163 441166 443169
      446170 450174 450178 449181 445184 441185 443188 447189
      452188 456185 461184 464176 460170 458167 462165 465167
      470170 475170 480171 485172 495179 501186 509193 518195
      527200 532195
 0.01 498667 496652 493643 489634 484630 480629 476629 467633
      462640 458647 455655 455663 457670 459672 465677 468679
      471683 472689 472692 471695 470699 472701 475703 477707
      480709 485708 487706 489702 494694 496686 498675 498667
 0.01 465700 463698 461698 457701 449710 448707 444709 439714
      439717 440719 445716 446720 443722 444724 443730 434727
      434730 438730 439731 443730 448728 453725 456719 458712
      461708 464703 465700
 0.01 438057 439048 439042 438040 438031 437026 435024 432030
      430037 426039 423042 424046 427050 432053 434059 436059
      438057
 0.01 263798 261798 257798 255799 252800 250802 248805 248808
      250808 252806 254805 256803 259802 261801 263798
 0.25 517262 516257 515255 512252 511249 509248 508248 506253
      506257 508260 509263 511265 512266 515264 517262
 0.25 506279 507274 506271 504264 501259 497253 494249 490244
      488247 489255 490262 493269 495275 498279 501281 504281
      506279
 0.25 517180 516178 515177 513177 512176 510175 508175 507176
      506177 506178 508180 509181 511182 513182 514182 516180
      517180
 0.25 494658 493650 491645 487637 483636 478637 471643 469647
      469653 470666 473670 476670 480672 481678 481683 482686
      484686 490680 492674 493669 494658
 0.25 492220 491215 487213 481210 477210 474211 468214 462216
      456218 459222 462223 466222 471219 478218 485219 492220
 0.25 504829 504818 503809 498799 493790 487784 482782 478782
      468786 462790 454792 414789 408791 404795 399805 397816
      396821 396828 395843 394855 390879 389886 389894 390901
      393904 396905 397903 399899 404889 408890 412892 421897
      425898 428896 431893 435890 445885 453879 456877 460879
      462885 462893 465900 468904 472905 476904 479901 483899
      487897 489891 494879 496873 496867 496858 497852 498846
      501842 503834 504829
 0.25 478241 479238 477235 475236 475237 475238 477240 478241
      478241
 0.25 484138 484136 483133 482133 481131 479130 478129 476129
      474128 473128 472128 472131 472133 471135 471138 472139
      473140 475140 477140 478141 480141 482141 483140 484139
      484138
 0.25 477159 476154 474151 471148 468144 465142 463143 460145
      458150 460154 463156 467160 470163 473163 477160 477159
 0.25 451100 448097 441097 438098 436100 437105 433106 430106
      423104 422107 424109 428110 431109 435112 438111 443114
      447110 447104 451100
 0.25 433097 432097 431094 429092 428091 427091 428093 428094
      429095 431096 432097 433097
 0.25 422117 418113 415108 412102 408098 404104 400106 394108
      389111 380117 380122 378124 374127 377130 382127 388127
      393124 395123 398124 404126 413121 422117
 0.25 427061 424056 422056 418057 414054 407053 402052 398053
      390058 382058 381066 380068 378067 376064 372062 367059
      364063 365065 368068 371072 372077 372084 387093 390090
      393089 396090 400088 407085 409080 413079 416075 417070
      419066 422067 423061 426062 427061
 0.25 375191 375188 372186 370184 366183 363182 359182 357182
      353184 351186 353189 356189 358189 362189 365189 369190
      372192 375191
 0.25 375053 375051 374050 372049 371050 370050 369051 367051
      365052 363052 361052 360054 359054 358056 359058 361058
      363057 363056 365056 366056 368056 370055 372054 374054
      375053
 0.25 367122 366121 365120 363120 362121 363122 364123 366122
      367122
 0.50 498261 498259 497257 496257 495257 496258 496260 497263
      498261
 0.50 491667 492664 492661 491659 491656 491654 489652 488655
      488656 488657 488660 487663 487665 487668 486669 486671
      487673 487674 489674 489672 490671 491669 491667 491667
 0.50 483644 481644 478645 476647 474649 473652 474657 475661
      477664 479664 480662 482658 482654 482652 483646 483644
 0.50 496827 496819 494812 491804 487800 483799 479801 477807
      482813 484817 482822 481828 481835 481839 476842 473851
      469859 466864 465869 469878 471890 478887 482884 484884
      488884 490880 491875 491867 489859 487852 484847 483841
      484839 486838 494833 496827
 0.50 470153 469152 467150 467152 467153 469153 470153
 0.50 467836 468827 467819 465816 460815 451812 443810 434805
      428800 420794 416793 412795 408800 406803 402813 400819
      401825 402829 405832 409835 409843 410849 412854 418854
      422853 426843 425839 426836 429833 435832 438834 445841
      454842 462840 467836
 0.50 442865 443858 441854 437851 432851 429848 425851 424858
      423862 424867 427871 431873 437872 440869 442865
 0.50 416064 406056 401054 397055 392059 389062 385061 384063
      384067 382071 379072 376066 373063 369061 367061 365063
      371068 373071 374075 374081 376083 380083 384085 387085
      384079 388078 389082 395082 397083 400081 403079 404075
      412075 415071 415066 416064
 0.50 408114 410108 410104 407104 405107 401111 397110 392111
      390114 387117 386120 389118 394117 397117 403116 406116
      408114
 0.50 366187 367185 366184 364184 363184 362184 361184 359184
      357184 356185 357187 358187 360187 362187 364187 366187
      366187
 0.50 372053 373050 372050 370052 368052 368054 370053 372053
      372053
 0.50 368054 367053 365053 363053 361054 359055 359056 359057
      361057 362056 363055 365055 366055 368054
 1.00 427817 427816 425816 423817 423818 423820 423822 425822
      427819 427817
 1.00 409068 408067 407065 405065 403066 402065 401065 400067
      401067 403068 405068 406069 408069 409068
 1.00 401074 402072 401070 400069 400068 399069 398069 396071
      396073 397075 399075 401075 401074
 1.00 399064 399060 397060 395062 393064 391065 389066 387069
      385072 387075 390075 392075 394071 396069 397067 399064
 1.00 374066 373065 372064 371063 370063 368063 367063 368064
      369065 371066 373067 374066

$$





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