Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 272056
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
356 PM EST TUE JAN 27 2015


PRELIM DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION
VALID JAN 28/0000 UTC THRU JAN 31/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR

DAY 1...

...NORTHEASTERN U.S. BLIZZARD...

THE STORM WILL BE PULLING AWAY FROM THE NORTHEAST EARLY IN THE
PERIOD...TAKING MOST OF THE SNOW WITH IT OUT TO SEA AND INTO THE
CANADIAN MARITIME PROVINCES.  THERE SHOULD STILL BE ENOUGH
MOISTURE INVOLVED IN THE BROAD CYCLONIC FLOW TO KEEP AT LEAST SOME
LIGHT SNOWFALL AMOUNTS GOING ACROSS PARTS OF NEW ENGLAND...MAINLY
IN THE UPSLOPE REGION...BEFORE ENOUGH DRY AIR GETS ENTRAINED INTO
THE STORMS CIRCULATION.

SATELLITE IMAGERY SHOWS THAT THE HIGHLY DIFLUENT TROF SEEMS TO
HAVE PEAKED IN INTENSITY AND THAT A SLOW WANE HAS
STARTED...SIMILAR TO WHAT THE OVERNIGHT MODELS WERE SUGGESTING.
THE 27/12Z MODELS WERE IN GENERALLY GOOD AGREEMENT WITH RESPECT TO
THE MASS FIELD DETAILS AND QPF OF THE STORM AS IT MOVES OUT TO
SEA.  THE BIG EXCEPTION WAS THAT THE 27/00Z ECMWF WAS A SLOW
OUTLIER COMPARED WITH THE NAM/GFS AND THE SREF/GEFS ENSEMBLE
MEANS.  THE EC IDEA OF BEING SLOW AND ON THE WEST SIDE OF THE
GUIDANCE HAS BEEN CONSISTENT OVER THE PAST COUPLE OF DAYS...AND
HAS PROVEN TO BE TOO SLOW WITH THIS STORM.  SO WE GAVE MOST WEIGHT
TOWARDS THE GFS AND SOME WEIGHT TO THE IN HOUSE WPC ENSEMBLE BIAS
CORRECTED GUIDANCE TO INCORPORATE THE GEFS/SREF GUIDANCE.

PLEASE REFER TO THE HEAVY SNOW DISCUSSION...QPFHSD...FOR WINTER
WEATHER DETAILS.

...SOUTHWEST/GT BASIN...

A RATHER ORGANIZED NEG TILTED UPR TROF WILL CONTINUE TO WEAKEN AS
IT LIFTS NWRD OVER CA BEFORE TURNING MORE EASTERLY AND MAKING ITS
WAY ACROSS PARTS OF THE GREAT BASIN AND CROSSING THE ROCKIES.  THE
MODELS STILL DEPICT A DECENT PLUME OF 1 INCH PWS OF THE EAST SIDE
OF THE UPR TROF INITIALLY WHICH DECREASES WITH TIME AS EVOLVING
SWLY H7 TO H5 FLOW ALLOWS SOME DRIER AIR ALOFT TO OVERSPREAD THE
SW WITH TIME.

STILL THINK THAT THIS SHOULD RESULT IN A GENL WEAKENING AND
SOMEWHAT DISORGANIZED AREA OF SHOWERS TO OCCUR OVER PARTS OF CNTL
CA/THE GT BASIN.  GIVEN THE WEAKENING TREND IN MID LEVEL FORCING
AND MSTR...PCPN PATRN IS EXPECTED TO BE RATHER DISORGANIZED AND
LIGHT MOST AREAS..AND AS A RESULT HAVE TAKEN A MULTI-MODEL BLEND
APCH TO PCPN ALONG WITH CONTINUITY.

DAYS 2/3...

...UPPER MIDWEST/GREAT LAKES/NORTHEAST...

SHORTWAVE ENERGY CROSSING THE CENTRAL PLAINS WILL STREAK OUT INTO
THE MIDDLE MISSISSIPPI VALLEY ON THURSDAY...JUST AHEAD OF A SECOND
SHORTWAVE DROPPING INTO THE UPPER MIDWEST.  THE INTERACTION OF
THESE FEATURES WILL LEAD TO AN AMPLIFYING UPPER TROUGH OVER THE
NORTHEAST/NORTHERN MID-ATLANTIC STATES ON FRIDAY...WHICH SHOULD
SWING OUT INTO THE ATLANTIC FRIDAY EVENING.  WIDESPREAD...BUT
MOSTLY LIGHT...PRECIPITATION IS EXPECTED WITH THE ASSOCIATED
DUELING SURFACE LOWS.  THE NORTHERN LOW SHOULD LIFT QUICKLY INTO
CANADA WHILE THE SOUTHERN LOW WILL TRACK STEADILY ACROSS THE GREAT
LAKES AND INTO THE NORTHEAST.  THE SOUTHERN LOW WILL HAVE THE
POTENTIAL TO RE-DEVELOP AND RAPIDLY DEEPEN OVER THE GULF OF MAIN
LATE IN THE PERIOD...WHICH COULD BRING MORE MOISTURE AND MORE
SIGNIFICANT PRECIPITATION INTO THE NORTHEAST.  FOR INFORMATION ON
THE WINTER WEATHER IMPACTS FROM THIS EVENT PLEASE REFER TO THE WWD
PRODUCTS AND DISCUSSION.

THE WPC FORECAST WAS LARGELY BASED ON A NON-ECMWF MODEL COMPROMISE
SINCE THE 12Z ECMWF APPEARED TO BE A SLOW OUTLIER BOTH WITH
LIFTING OUT THE DEEPENING COASTAL LOW AND WITH PUSHING THE
TRAILING COLD FRONT OFFSHORE.


...SOUTHWEST/SOUTHERN ROCKIES...

PRECIPITATION WILL BEGIN BREAKING OUT ACROSS THE SOUTHWEST AND
SOUTHERN ROCKIES...BENEATH AN AMPLIFYING UPPER TROUGH SLOWLY
EDGING IN OVER CALIFORNIA/NORTHERN MEXICO/SOUTHWEST LATE THIS
WEEK.  LOW LEVEL FLOW AHEAD OF THIS FEATURE WILL STREAM AN
ANOMALOUS AMOUNT OF PACIFIC MOISTURE INLAND AND ALLOW FOR SOME
WIDESPREAD MODERATE TO HEAVY PRECIPITATION TOTALS.

DETERMINISTIC GUIDANCE WAS GENERALLY IN GOOD AGREEMENT WITH THE
MASS FIELDS IN THE SOUTHWEST...SO THE WPC FORECAST STARTED WITH A
BLEND OF THE 12 GFS/ECMWF...WITH AMOUNTS MANUALLY BOOSTED ALONG
THE UPSLOPE SIDE OF THE TERRAIN IN THE MOGOLLON RIM.


BANN/GERHARDT

GRAPHICS AVAILABLE ON THE WEB AT WWW.WPC.NCEP.NOAA.GOV


24HR QP VT 29/00Z
 0.01 537164 538153 537148 535142 533136 531130 530125 527113
      521102 517100 513103 511108 512113 513120 514126 517140
      517147 514152 511152 509153 507158 506164 501167 499170
      502176 504186 503194 503200 500205 496207 491207 486206
      476206 465204 463209 459212 454215 451218 441218 439222
      445224 447226 447229 445232 437237 433240 432245 433251
      436256 440259 444258 448254 452255 454253 457248 459245
      460245 466244 471236 475232 477231 480231 485230 490232
      499230 501226 503220 507214 510211 513211 514208 513201
      525187 533174 537164
 0.01 541030 541022 540016 534005 532000 531992 530985 530976
      528968 528959 526946 525937 523931 520918 517904 513892
      510880 509862 508857 507854 506846 504841 499842 495838
      493833 490828 487825 485824 482823 478826 475830 473836
      466843 465849 465856 469868 474878 477889 479904 481912
      478917 475920 472924 472939 472947 474952 479963 484975
      487986 490000 498023 508042 515049 519053 523055 531052
      534049 537043 541030
 0.01 500645 499638 498635 493627 488623 481623 478622 474623
      465627 456629 454628 449629 444635 437639 426651 418664
      409678 406685 401691 398699 398703 399709 400714 402719
      407724 410725 414725 420728 423732 425735 427739 429741
      434740 437741 441741 444742 448744 450742 454740 456737
      460731 466725 473710 477707 482707 483708 485705 486694
      487684 486678 488674 492672 494668 497663 499657 500645
 0.01 491139 489137 487135 486133 483130 481129 479130 476131
      474133 474136 475137 479137 482138 484136 487139 489140
      491139
 0.01 483168 481162 479157 474153 469148 466144 463143 462146
      465152 465157 467158 469165 469168 472169 479171 483168
 0.01 457118 458098 456092 455084 455079 453076 450073 448070
      448066 451061 448054 445050 437049 432047 427042 423040
      418038 415045 413052 412055 408056 404053 399057 393059
      389062 385066 382072 380080 382086 384088 386086 391084
      413080 416078 417074 418070 419067 424064 429068 430070
      431074 431081 431089 428089 425086 421083 421091 424096
      424101 422102 418106 415108 412106 410096 402106 402109
      404110 403113 400115 396120 397122 400123 405120 411120
      413129 416134 416139 414143 410146 401151 398156 394161
      392165 391169 393174 395182 398185 405187 408186 411186
      417185 420183 431176 434174 433169 434166 437165 439161
      442162 443160 443154 445152 449148 453142 454133 457118
 0.01 394798 393795 391793 388794 386796 384798 383801 381803
      380806 378807 378812 380813 382811 385809 387807 389805
      390802 392801 394798
 0.25 524033 523031 522028 521025 520024 520023 519020 518022
      518025 519026 520028 520030 521031 522033 523034 524033
 0.25 520002 517970 514954 512939 509922 505908 502894 499889
      498882 495876 491871 487871 486879 486886 488893 489904
      492920 496933 499947 502962 505977 508991 512003 513011
      516016 518015 518012 517008 520002
 0.25 471678 470671 468669 464669 461668 458665 458659 459655
      462653 463648 461645 455643 450643 445645 442647 440650
      431665 424681 423685 420688 415694 417696 422695 430696
      435695 439694 443692 447692 454697 461693 467687 471678
      471678
 0.25 449119 450113 449107 448103 446100 441098 434099 430107
      426113 427121 430128 432130 435130 440126 446123 449119
 0.50 443666 443664 443661 442661 441662 441663 439665 438668
      437671 436673 435675 435676 436678 438678 439678 440677
      441676 442674 442673 443671 443669 443668 443666
 0.50 445111 445110 445109 444106 442105 441105 440106 439107
      438107 437110 438112 439112 440113 442114 443113 445112
      445111

24HR QP VT 30/00Z
 0.01 521750 518724 514715 512712 508710 505709 502709 494711
      485714 481720 470731 467733 464735 459738 453739 448739
      445738 440734 438733 434733 426736 417747 414750 408752
      403753 399755 394756 391759 388760 386763 383770 382777
      383782 381786 377794 372801 367807 362814 361817 361823
      362832 359839 351853 351857 349861 351866 352868 354868
      359868 361865 364864 366869 370873 377873 381873 384870
      392872 406881 415891 427900 431905 434914 435919 438923
      440927 444928 453928 458923 460925 462930 463934 464940
      464952 464957 466960 469962 472962 481957 484955 488955
      497955 509950 511949 514944 516936 518926 519922 520918
      520912 520897 519892 518887 514869 512861 512856 513851
      516841 520832 523821 522810 521787 519763 521750
 0.01 492256 493253 492252 492250 491248 490247 490246 489244
      488243 487242 486243 485245 484245 484246 485248 486249
      487250 488252 488253 489255 490256 491256 492256
 0.01 481242 482237 480234 479231 477229 474229 472231 469232
      467233 465235 464239 466241 469242 473243 476244 479243
      481242
 0.01 477215 478213 478210 477209 477210 476211 474211 473211
      472212 470213 468214 468215 467217 468218 469218 470218
      471217 473216 475215 477215 477215
 0.01 449114 449112 449109 447108 446106 444105 442105 442106
      441108 442109 443111 445113 445114 447114 448114 449114
 0.01 440096 440093 438090 436092 434094 431092 430090 426091
      426092 427094 429097 432099 434100 436100 438098 440096
 0.01 408154 407151 403151 396148 391144 387145 388148 386152
      382156 376159 372165 370173 369176 365177 363178 361183
      360185 362186 370190 374194 376193 379190 377183 377180
      378176 382172 389169 393165 396159 398157 402156 406156
      408154
 0.01 416064 412062 409064 407062 408058 406055 401055 402060
      401067 402069 406072 408075 411073 414071 414066 416064
 0.01 405109 405107 403109 400106 398106 398108 396110 392112
      392114 394115 396113 398113 401111 403111 405109
 0.01 393071 393068 392068 391068 390068 389070 388070 388072
      389073 389072 390071 392071 393071
 0.01 385052 385051 383049 383048 381048 379048 378048 376047
      374047 372048 370049 370050 369052 370053 372054 374054
      375054 377054 379054 381054 383054 385052 385052
 0.01 353119 353116 351114 348111 344107 342102 343094 343087
      336081 331078 327080 327085 330089 330092 330096 329103
      324104 322108 331113 336116 340115 345116 349120 353119
 0.01 344173 345171 344170 343169 343168 341167 339167 339168
      340170 340171 341173 342174 344174 344173
 0.01 269800 268799 267798 266798 264798 262798 261799 259800
      257800 255800 254801 253802 252803 251804 252805 254805
      256805 258804 259804 260803 261802 263802 265802 266801
      268800 269800
 0.25 500827 498796 498786 497771 493743 486746 479753 476755
      471757 460761 456763 453766 449775 445784 443791 446795
      445805 442803 440798 438793 433793 421792 418792 414789
      410787 406790 403800 403806 407810 411818 412823 414828
      420835 427843 433848 437851 442849 448842 451838 452831
      451827 453826 455828 457829 460827 465826 467826 468829
      468838 468843 467846 466851 467857 469860 472859 477867
      486873 491866 493862 495855 499839 500827
 0.50 483796 483794 482791 481791 480792 479792 478793 476794
      476795 475798 477800 479801 480800 481799 482798 483796

24HR QP VT 31/00Z
 0.01 434632 449640 463648 467649 473649 482647 499650 503652
      505654 509668 509689 511692 514697 515705 517711 518719
      518725 515738 507756 498773 491781 485786 478792 473796
      468797 462802 458806 456812 456820 454824 452828 449830
      439832 436832 432830 422827 416828 412831 406832 403834
      398835 395836 393837 375839 370840 365842 361844 357848
      350854 344860 340863 335864 332865 329864 326861 325856
      326852 333846 340841 344838 347834 355817 359812 362810
      364807 368804 383793 390787 396779 398774 399769 398761
      395759 387754 378751 374749 368751 365754 363757 360765
      353774 346780 343783 342788 340799 334806 329814 325821
      320821 317817 316804 319795 321784 319780 318774 316770
      316764 318759 316755 314751 313745 305742 305735 305729
      306723 308719 312712 318702 323691
 0.01 523264 521260 516258 513255 511250 507242 502241 502244
      504249 503254 501258 499257 497255 494253 491255 491260
      493265 496268 498274 502283 504287 508290 513282 514279
      516279
 0.01 545057 545048 545044 544041 541027 537018 529010 527006
      523004 522000 522996 522986 521979 519973 517967 514962
      507957 504954 497954 495958 495967 497972 500975 506985
      510998 509007 509016 512027 516032 518036 524047 527058
      530064 531069 533072 535072 539073 542067 544060 545057
 0.01 525193 525187 523181 519179 517176 514173 511169 508166
      506172 508177 509181 512186 515190 518193 521195 524193
      525193
 0.01 479870 478866 476863 471858 467853 464851 460851 456849
      454847 452845 449845 444851 442854 438856 435858 431859
      422860 419865 417868 419870 426872 435871 447865 451864
      454864 460869 462878 466885 471885 474882 475877 478874
      479870
 0.01 408117 408116 407114 407112 409110 409108 409107 407105
      407107 405109 405112 403113 401113 403116 404116 406117
      408117 408117
 0.01 402141 402139 400139 398140 398141 398143 400144 400143
      402141 402141
 0.01 408070 406067 403067 399071 397069 397065 396060 393057
      390054 386053 382051 378046 376042 375036 379026 383017
      383006 380001 376999 371998 367996 364994 362991 356983
      349980 344978 339978 334980 331982 328984 325987 321990
      318990 315988 306987 303989 300992 300995 299998 297000
      294006 291010 283014 283019 285022 295023 301024 304029
      305033 303038 301041 298042 288045 280048 277051 271052
      263055 259056 254056 250053 246052 239054 237058 238062
      240066 243068 246078 249085 253089 258092 260094 261100
      259106 254107 248107 244108 243110 244115 250119 255122
      260123 265122 270122 279119 286121 290123 296125 305128
      315130 321131 324133 326139 330142 340145 347150 350153
      348156 343155 339157 336159 330159 326158 321156 317154
      313152 310149 308153 312155 316159 323163 340172 345174
      348172 355169 362163 364159 365153 363150 361148 361145
      364141 368143 373144 376142 380132 382127 386123 392119
      395117 396112 390105 387100 388093 391089 391084 400076
      403071 408070
 0.01 376189 377187 375184 374182 371179 369178 365177 362177
      360178 357178 356180 357181 359183 362184 366185 369187
      371189 374189 376189
 0.01 326181 327176 326171 323167 320164 316163 312163 310167
      313169 316172 318175 320179 322183 326181 326181
 0.01 312867 312864 312862 311862 310862 309863 308864 307865
      306867 306869 306871 308872 309871 310870 311869 312867
      312867
 0.25 416638 422643 422647 421651 419656 417660 411665 408667
      406671 406680 409683 408686 405689 400692 393695 391697
      388702 377714 365724 358727 349728 343725 340723 336722
      334712 334708 333701 330694 330686
 0.25 492736 470726 471718 474710 480704 484697 486687 484679
      478674 475672 472672 464673 457671 451667 445665 441667
      439671 439680 435682 432682 428683 425686 427691 427695
      429697 434702 437705 438712 437722 435726 432727 430731
      431736 433740 432745 428753 427757 429761 434766 439762
      441759 441752 444749 447749 456760 460760 464757 469752
      474747 482746 488742 492736
 0.25 393798 394796 393796 391796 390796 389797 388798 387799
      386800 385802 385803 384804 385805 387804 388803 390801
      392800 393798 393798
 0.25 377078 377074 376069 374065 372063 368061 366058 362049
      360041 357034 354030 350029 343029 329034 321036 315042
      310048 307056 305060 302062 295065 288068 282072 274073
      270075 267078 268083 270087 274093 286103 290109 297113
      305116 316118 321118 324120 329126 335132 341136 346137
      351137 357134 363130 369124 374105 373096 371086 374080
      377078
 0.50 472695 471690 467688 463687 460686 456684 453683 452686
      453693 456697 458699 462701 467700 470698 472695
 0.50 412651 413649 412647 411646 409645 408646 406646 404647
      402648 401649 400650 400652 400653 401655 402655 404655
      406655 407655 409654 411653 412652 412651
 0.50 382690 381688 378687 375688 371690 370692 368693 367698
      369702 373700 375699 378697 380695 382692 382690
 0.50 378661 378659 377658 375658 373659 372659 370661 369661
      369662 367663 366664 365665 365667 365669 366670 368669
      370668 371667 373666 374664 376663 378662 378661
 0.50 373711 372708 371710 369711 369712 371712 373711 373711
 0.50 364112 364109 362104 360100 357099 353100 350098 346091
      341084 343078 345076 351079 357086 359084 358080 356076
      355072 358068 356064 355059 357056 358053 356049 352043
      349040 346039 338041 323045 317050 313058 312063 312070
      310074 308076 299072 294072 291073 284077 281078 276078
      273080 273085 280090 302110 310113 318113 323113 327115
      332121 338127 344131 347132 350130 357124 362120 364112
 1.00 347119 349115 348112 346109 343105 341100 339091 336082
      334079 329077 326078 325081 325087 325093 324100 321104
      324107 333111 336114 338119 339122 341124 344122 347119
 1.00 316105 316103 314101 312101 312100 310100 309100 307100
      307102 308104 309104 310105 312106 313107 315106 316105

$$





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