Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 272258
QPFPFD

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


FINAL 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 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 537150 538148 538145 538142 538141 537139 536138 535137
      533137 532138 531140 531141 530143 530146 529148 529151
      529154 530155 532156 533155 534155 535154 536153 537151
      537150
 0.01 541030 541022 539015 534005 532000 531992 530984 530976
      528968 528958 525944 525936 523930 520918 516903 513892
      511887 509878 509862 508857 507854 506845 504841 498842
      492832 490828 487825 485824 482823 478827 473837 466843
      465849 465856 469868 474880 477891 479904 481911 480914
      478917 472925 472941 472947 474952 480964 484977 490000
      498024 508042 516050 520053 524055 531052 534048 537043
      541030
 0.01 524184 525174 524167 523163 516161 511165 508166 504166
      501167 500170 500175 501178 507185 510193 514197 520194
      522187 524184
 0.01 500645 499639 498635 493627 489623 483622 479622 475623
      467626 459628 453628 448630 446633 441640 435652 433657
      430660 425664 420669 416674 413677 411681 409690 406696
      405705 404710 405716 406719 410721 423723 432722 435723
      437727 437731 439736 442737 449732 459722 464715 467708
      477699 481690 481679 486674 492672 496665 499659 500645
 0.01 501225 500219 498213 493210 488210 483206 479207 472211
      467214 462215 458216 455219 452219 449219 443217 440219
      441223 447226 446230 444232 437236 433241 433245 433251
      436256 440259 445258 448255 451250 454246 458242 465239
      465236 464233 463229 465227 472222 477220 482220 487222
      491225 494228 498229 501225
 0.01 495158 496156 496153 494152 493150 491150 489152 491153
      492153 494156 495158 495159 495158
 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 463144 462146
      465152 465157 467158 469165 469168 472169 479171 483168
 0.01 457118 458106 458097 456088 455079 448070 449058 446051
      440049 436049 432047 428042 417038 413052 412055 408056
      404053 403054 391061 383068 381076 381081 382086 384088
      389085 397085 402083 407080 414080 416078 417075 418071
      419067 424064 429068 432085 433089 430090 425089 422088
      421089 422093 424095 426098 425100 419104 415109 413111
      411108 409103 407103 407106 405109 402111 399115 397118
      397122 400123 403121 406120 410120 414121 418121 420124
      420129 417135 415141 412145 406151 402151 399148 395149
      391155 391158 393157 395159 391172 387177 387180 391181
      397185 400185 404184 409183 416184 420185 422184 426182
      436172 440166 444162 448158 448155 446153 444150 446149
      449148 453142 454132 457118
 0.01 394798 393795 391793 388794 386797 384799 383801 381804
      380806 378807 378812 380812 382811 385809 387807 389804
      390803 392801 394798
 0.01 357837 358834 357832 356832 356835 355836 355837 353838
      353839 354840 355840 356839 357837 357837
 0.25 524033 523031 522028 521025 520024 520023 519020 518022
      518025 519026 520028 520030 521031 522033 523034 524033
 0.25 520002 520993 518983 516970 514954 512939 509922 505909
      501894 498882 495876 491871 487871 486879 486886 488894
      489900 490907 494922 497937 503965 505980 509993 511000
      512009 514015 516016 518015 518006 520002
 0.25 469674 467669 463669 457666 456655 454646 449647 446649
      440655 432670 424685 421688 418691 417694 419695 424696
      426700 430706 426710 431711 434711 438710 441706 445705
      451704 458698 462691 466683 469676 469674
 0.25 450114 449107 446101 441099 436101 432105 428108 426113
      427115 428125 428128 431128 435125 441125 446122 450117
      450114
 0.50 444111 444108 442107 440107 440108 438109 437110 438111
      440111 442113 443112 444111

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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