Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 271832
QPFPFD

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


PRELIM DAY 1 QPF DISCUSSION
VALID JAN 28/0000 UTC THRU JAN 29/0000 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 MARITIMES.  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.

BANN

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

$$





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