Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 252152
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
451 PM EST SUN JAN 25 2015


FINAL DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION
VALID JAN 26/0000 UTC THRU JAN 29/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


2200 UTC UPDATE

NO SIGNIFICANT CHANGES MADE TO THE PRELIM DAY 1 QPF FOR THE FINAL
ISSUANCE.

DAY 1...

...OHIO VALLEY EAST THROUGH THE MID ATLANTIC AND SOUTHERN PORTIONS
OF THE NORTHEAST...

THE MODELS CONTINUE TO COME INTO BETTER ALIGNMENT WITH THE
EVOLUTION OF THE SYNOPTIC FEATURES DURING DAY 1...AS A VIGOROUS
SHORTWAVE AND ASSOCIATED SFC LOW AND FRONTAL ZONE CURRENTLY ACROSS
THE MID MS VALLEY PIVOTS EASTWARD TOWARD THE MID ATLC COAST DURING
THE FIRST HALF OF THE PERIOD. AS IS TYPICAL WITH THE "MILLER B"
TYPE EAST COAST CYCLOGENESIS...EXPECT THE TYPICAL TRANSFER FROM
THE SFC CYCLONE PRIOR TO REACHING THE APPALACHIANS TO A
NEWLY-DEVELOPED LOW OFF THE NORTHEAST NC/SOUTHEAST VA COAST. IN
TERMS OF QPF...THERE WAS BETTER CLUSTERING WITH AMOUNTS DURING THE
DAY 1 PERIOD (00Z MON-00Z TUE)...HOWEVER THERE REMAINED SOME
TIMING DIFFERENCES IN TERMS OF HOW FAST THE PCPN SPREADS INTO THE
NORTHEAST TOWARD THE END OF DAY 1 (INTO SOUTHERN NEW ENGLAND). THE
NAM AND ECMWF CONTINUE TO BE SLOWER COMPARED TO THE GFS AND
RGEM...AND AS A RESULT WPC UTILIZED AN ENSEMBLE APPROACH WITH
RESPECT TO THE TIMING (INCLUDING THE UKMET). AREAL AVERAGE AMOUNTS
THROUGH DAY 1 TOP OUT BETWEEN .25 AND .50 ACROSS INTERIOR PTNS OF
THE NORTHERN MID ATLC AND ERN PTNS OF THE OH VALLEY...WITH THE
SECONDARY SWATH OF .25+ INCH AMOUNTS ALONG THE NJ COAST ENE
THROUGH LONG ISLAND ASSOCD WITH THE RAPIDLY DEEPENING COASTAL LOW.
FOR FURTHER INFORMATION REGARDING THE WINTER WEATHER IMPACTS FROM
THIS SYSTEM...PLEASE REFER TO OUR LATEST SUITE OF WWD PRODUCTS.


...SOUTHWEST...

HIGHLY AMPLIFIED...NEGATIVELY TILTED MID/UPPER LEVEL TROUGH
PIVOTING TOWARD NORTHWEST BAJA AND SOUTHERN CA WILL PROVIDE
STRENGTHENING UPPER LEVEL DIVERGENCE/DIFFLUENCE AND ANOMALOUS
MOISTURE (PWATS INCREASING TO 3-4 STANDARD DEVIATIONS ABOVE
NORMAL) INTO FAR SOUTHERN PORTIONS OF THE SWRN U.S. (SOUTHERN
CA-AZ). GIVEN THE AMPLITUDE OF THE UPPER-LEVEL PATTERN AND TIGHT
SW-NE GRADIENT OF DEEPER LIFT/MOISTURE...EXPECT A FAIRLY SHARP
GRADIENT OF THE MORE ROBUST ISENTROPIC ASCENT AND (THUS) PCPN
AMOUNTS. WPC ESSENTIALLY WENT WITH A NON-NAM COMPROMISE ACROSS FAR
SOUTHERN CA/AZ (NAM A NOTABLE WET OUTLIER...ESPECIALLY CONSIDERING
THE LACK OF DEEP-LAYER INSTABILITY). THE UPSHOT WAS AREAL-AVERAGE
TOTALS BETWEEN .25 AND .50 INCH OVER THESE AREAS.


DAYS 2/3...

...MID ATLANTIC/NORTHEAST...

WHILE NUMEROUS DIFFERENCES IN THE DETAILS REMAIN...A GROWING MODEL
CONSENSUS NOW INDICATES THAT WIDESPREAD MODERATE TO HEAVY
PRECIPITATION...FALLING IN THE FORM OF SNOW...WILL SPREAD FROM THE
NORTHERN MID ATLANTIC COAST MON NIGHT TO DOWN EAST MAINE BY TUE
AFTERNOON.  SPURRING THIS DEVELOPMENT IS A WELL-DEFINED MID-UPPER
LEVEL SHORTWAVE TROUGH EXPECTED TO MOVE OFF OF THE
SOUTHEAST/MID-ATLANTIC COAST LATE MON...ASSUMING A NEGATIVE TILT
AHEAD OF AN UPSTREAM WAVE DIVING THROUGH THE GREAT LAKES/OH
VALLEY.  A RAPIDLY DEEPENING SURFACE LOW IS FORECAST TO TRACK
SLOWLY NORTH ALONG THE NORTHERN MID ATLANTIC COAST...NEARING
EASTERN LONG ISLAND/SOUTHERN NEW ENGLAND EARLY TUE.  STRONG
ATLANTIC INFLOW INTERACTING WITH LARGE SCALE ASCENT AFFORDED IN
PART BY AN UPPER JET COUPLET IS EXPECTED TO PAINT MODERATE TO
HEAVY AMOUNTS FROM THE NORTHERN DELMARVA/NJ TO DOWN EAST MAINE.
SOME OF THE GUIDANCE SUGGESTS THAT LOW-MID LEVEL FRONTOGENESIS
UNDERLYING NEGATIVE EPVS WILL PROMOTE MESOSCALE BANDING --
PROMOTING LOCALLY HEAVIER AMOUNTS ACROSS PORTIONS OF NORTHERN
NJ..SOUTHEASTERN NY AND SOUTHERN NEW ENGLAND.  BY TUE EVENING THE
POTENTIAL FOR WIDESPREAD HEAVY AMOUNTS IS EXPECTED TO DECREASE AS
THE BETTER MOISTURE ADVECTION/FORCING SHIFTS FURTHER EAST.  THE
GROWING MODEL CONSENSUS IS REFLECTED IN THE WPC QPF...WITH HIGHER
CONFIDENCE IN HEAVIER AMOUNTS REACHING FURTHER WEST ACROSS THE
REGION.  HOWEVER...THIS CONFIDENCE WAS TEMPERED SOME BY LINGERING
MODEL DIFFERENCES WITH RESPECT TO THE TRACK OF THE LOW AND THE
RUN-TO-RUN CHANGES THAT EACH NEW MODEL CYCLE BRINGS.  WPC AMOUNTS
REFLECT A BLEND THAT GAVE SIGNIFICANT WEIGHT TO
NAM/ECMWF...ESPECIALLY THROUGH THE DAY 2 PERIOD (LATE MON-LATE
TUE).  WHILE NOT COMPLETELY DISMISSED...LESS WEIGHT WAS GIVEN TO
THE GFS...WHICH SPREAD PRECIPITATION MORE QUICKLY TO THE NORTH
THAN THE MODEL CONSENSUS.  REFER TO THE WPC WINTER WEATHER SUITE
FOR FURTHER DETAILS ON THIS POTENTIALLY MAJOR WINTER STORM.

...CALIFORNIA/SOUTHWEST/GREAT BASIN/NORTHERN AND CENTRAL GREAT
BASIN...

AN UPPER LOW SPINNING OFF OF THE COAST OF BAJA IS FORECAST TO LIFT
TO THE NORTH INTO SOUTHERN CA BY EARLY TUE...SHEARING INTO AN OPEN
WAVE AS IT MOVES INTO THE GREAT BASIN LATE TUE.  DEEP
SOUTHWESTERLY FLOW AHEAD OF THE SYSTEM WILL RAISE PWS TO
ANOMALOUS LEVELS...FUELING WIDESPREAD COVERAGE OF LIGHT-MODERATE
AMOUNTS ACROSS SOUTHERN CA..THE SOUTHWEST AND THE CENTRAL GREAT
BASIN.  LIGHT TO OROGRAPHICALLY FOCUSED MODERATE AMOUNTS ARE
EXPECTED TO SPREAD FURTHER NORTH AND EAST WITH THE SYSTEM ON DAY
3...REACHING WESTERN WY/CO BY THE END OF THE PERIOD.  WITH THE
MODELS IN GOOD AGREEMENT OVERALL WITH THIS SYSTEM...WPC AMOUNTS
GAVE MORE WEIGHTING TO THE HIGHER RESOLUTION ECMWF/NAM.

HURLEY/PEREIRA

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


24HR QP VT 27/00Z
 0.01 568002 569991 568980 566963 563949 560941 557936 550925
      547920 543916 536909 533907 533902 534899 534893 533872
      530855 525843 521839 516840 503842 501844 497845 492846
      481851 468853 444860 424871 419874 416879 414880 413883
      410890 408896 408903 410910 413914 417917 419919 422919
      429921 435922 447925 453935 462942 471948 477950 481952
      484953 486957 487962 491967 496970 500975 503975 505978
      511979 516981 525987 529990 532995 541004 548014 552017
      555018 560015 564010 568002
 0.01 531235 533229 534223 537215 538210 539204 540197 539187
      534181 533171 531164 527156 523151 510146 503146 495145
      491148 491152 492156 495164 497167 500170 506172 509174
      511178 511183 512187 516195 520210 521219 524227 524233
      522236 519244 516244 514240 510234 506232 504244 504254
      503267 501278 498287 494295 490302 487309 484318 484320
      486323 490326 494326 499325
 0.01 314697 285728 279735 272741 264759 259769 253777 247786
      240793 236797 235804 234814 233819 240818 242819 241823
      241827 239833 239836 243848 248849 254846 257846 259852
      262856 264860 262862 262870 265874 268876 272876 276873
      279869 291853 296843 295835 298832 321798 327790 331786
      334785 340786 344790 353793 357798 356803 357809 354813
      345831 343837 341843 335851 333862 328870 326875 325880
      328883 335883 340882 344882 347884 350886 354890 357894
      360899 366906 370911 374914 377915 380911 383905 385897
      385892 386885 387878 389874 392871 396867 403860 409851
      412846 414838 416826 417812 422801 428793 432790 433783
      434770 436758 432742 428731 412682 408667 406661 402657
      398653 391654 387657 381659 361671 342681 324690
 0.01 213120 218132 222137 226142 236150 247158 260164 267168
      275170 283170 289168 300163 307162 311162 314164 327171
      332175 337180 343193 345194 347192 348187 352186 358184
      356182 352181 349179 352170 352163 351155 348148 344142
      343139 345136 351140 353137 353133 351130 346125 343120
      335108 328095 322083 319077 315071 312065 308060 305057
      301057 294056 291062 292065 288064 285060 279055 269048
      255042 246041 240042 236047 235053 238060 243065 249069
      255073 262083 267087 273090 277095 278099 278104 273109
      265108 251103 245100 240096 230089 225087 220088
 0.25 523262 521259 520256 518254 515253 514254 512255 511260
      510265 509270 508275 509278 508283 507285 506290 506292
      509296 512295
 0.25 532205 532203 532200 532198 532197 532195 531193 529193
      528193 527193 526196 526198 526201 527202 528204 528205
      529207 531208 532205
 0.25 420773 419767 417764 411759 408756 404756 399756 397759
      392767 387773 378785 370800 377814 389824 392827 395829
      398832 401830 404826 406822 410815 413806 416797 418788
      419784 418778 420773
 0.25 410718 410711 408704 404694 401681 397672 394668 391667
      384667 379670 371674 364679 356685 348691 335703 320714
      314719 307726 296740 291746 287754 286759 286762 284772
      285779 287783 287787 289791 295796 305797 309797 313794
      318788 324781 331775 342761 348756 356750 364745 373741
      378741 382743 385747 388749 392748 397745 400743 403739
      408729 410718
 0.25 373849 372844 368842 365844 362847 360852 360854 362860
      364864 366868 368869 370864 371858 372853 373849
 0.25 362825 361821 359823 358826 356828 354830 353834 352837
      353842 354841 356839 357837 359834 360830 361827 362825
 0.25 332153 331147 330141 325131 319123 315119 311117 299113
      294114 290119 290122 291129 292135 292138 290139 278134
      273132 268132 259138 250142 248145 253149 259150 266151
      278151 283150 288148 292146 299146 306147 312150 317152
      320156 325163 329162 330158 332153
 0.25 287818 287816 286815 284816 283817 283818 282819 281820
      281821 280823 281825 282826 283825 284825 285823 286821
      287819 287818
 0.25 274075 274073 273072 271071 269070 267069 266068 264067
      263068 263070 264070 265072 267074 268074 269075 270075
      272076 274075 274075
 0.25 237117 236115 235115 234114 232114 230115 229116 228118
      229120 229121 231122 233122 235121 237119 237118 237117
 0.50 518276 517275 516275 515276 515277 514280 515280 516281
      517281
 0.50 402713 401703 398695 392683 387677 381676 374678 368682
      358689 348698 328716 319725 313736 308750 306756 306759
      307761 308765 310768 315773 318774 321772 327769 333765
      338761 347752 352748 358745 371739 377736 385733 392732
      396727 401720 402713
 0.50 407778 408773 407770 404769 401769 399770 397772 395775
      394778 393780 393785 394788 396789 400788 401788 404785
      405783 406780 407778
 0.50 314137 313135 311133 309132 307130 305127 303125 301123
      298124 298128 299131 301133 303135 304138 306139 308141
      310141 312139 314137
 1.00 383720 383714 381709 377704 371702 367702 362703 355707
      350711 339721 337723 336727 337734 328744 328749 331751
      339749 345748 352745 363737 372734 377730 382725 383720

24HR QP VT 28/00Z
 0.01 327700 337691 360657 381635 416614 440608 471611 483617
      489635 492653 491662 489669 485684 481695 476706 471719
      464730 461736 457741 449752 444757 439760 436761 434764
      437770 441784 437792 430800 419807 405808 398808 396810
      391811 385814 381818 376821 369821 367823 366826 366834
      367839 368842 370846 374851 380854 390858 415856 427860
      432861 440860 452860 461854 466851 471850 481844 488843
      492843 494840 500840 504841 506843 508848 510858 511869
      509872 509878 509882 508885 504888 499891 492892 485892
      483897 484901 486917 485925 482932 477920 473914 466913
      464911 459911 453911 446911 443911 441909 432904 423897
      418894 411894 410892 406892 401888 396884 392879 387875
      380873 369869 360865 355862 353856 348844 348837 351831
      357821 368813 374811 376803 377800 375796 371790 366781
      363775 361769 360765 358764 355762 352763 349769 349773
      350775 354780 358787 361794 356795 343793 327795 324797
      319796 311797 308797 306796 300794 296790 293785 288781
      284767 286760 288754 290748 295741 302730 327700
 0.01 539199 539193 539188 537185 532176 528166 520159 518155
      512155 512164 512169 509169 506169 505171 508183 509193
      505213 503214 500213 497209 494206 490206 486204 481205
      474210 459217 455221 455223 457225 457229 455231 451233
      446233 443235 436242 430251 427256 426262 425266 429265
      436260 444253 447250 452249 457249 460249 462258 464261
      467263 469266 474268 478268 481268 484270 486274 491282
      494286 500289 505290 509286 515279 520270 522263 523258
      521252 522247 524245 528243 530239 533225 537210 539199
 0.01 520237 520231 520228 521223 520220 519216 515214 513218
      512220 511226 512228 513233 514237 516239 519239 520237
 0.01 490234 491229 491226 488223 484224 481223 478222 475222
      474227 477229 479231 481233 484232 486233 488235 490234
 0.01 415194 421188 419177 423168 422154 422139 427123 426116
      420112 416113 410115 406118 401118 398119 396115 394112
      391112 384113 378114 375116 370118 363113 358112 354110
      346096 343089 341085 341080 338076 335073 333070 327065
      320064 317057 312051 305047 300044 286039 288044 293050
      297057 298062 300071 294077 286085 285094 292104 293114
      294118 297122 301127 304129 308130 312131 314133 316142
      315153 314159 316163 320170 324176 329183 331189 334204
      336213 337216 341217 343213 346211 346216 348220 352225
      356226 358224 360220 363218 365213 365207 358202 357198
      357193 364193 368194 371197 382206 389209 396215 403218
      403224 403226 405227 410228 412224 413221 413216 406216
      402210 403205 405201 410195 415194
 0.01 396138 395135 396131 396126 395124 392121 388123 386125
      385127 383129 382131 381134 383136 386137 388140 391141
      393139 396138
 0.01 386086 384081 381078 379076 376075 373080 373084 375089
      376096 376101 379099 382097 384092 386086 386086
 0.25 377659 383651 398636 417628 436625 455616 470625 475632
      477639 479647 479655 478668 475681 470692 466701 460711
      449732 434746 417760 408765 402766 396767 385765 380763
      377758 374745 371740 367737 362738 357741 354744 350749
      342768 339771 334774 328776 320777 315776 311773 306765
      304761 305753 309743 319726 324717 332708 344693 354687
      361679 370667 377659
 0.25 532203 533195 531190 529186 527181 525177 523173 519172
      517177 517182 519188 521194 524198 525201 530204 532203
 0.25 517267 518262 518259 515253 510241 506235 502230 499226
      494223 494228 496235 502246 504253 505260 504265 502264
      497261 494262 493264 495270 501273 506274 511272 515269
      517267
 0.25 361132 357122 352117 345112 342108 341104 337100 334102
      327107 332114 336121 338130 347135 350138 353135 361132
 0.25 348196 348194 348192 348190 349187 348186 346186 344187
      344189 344191 344193 345194 345196 346197 348196
 0.25 332167 332166 330165 329164 327165 328167 330168 332168
      332167
 0.50 392651 402642 415635 430637 444631 457628 467633 471640
      473648 473656 473662 472669 467674 465687 461696 455705
      450717 447722 443726 438734 431742 423749 413756 405759
      399760 393760 389758 385754 384747 384739 384731 382724
      380720 374721 367722 361722 351719 347722 346726 344731
      343737 342752 340757 338762 333765 328764 324760 322756
      318753 320741 323736 327728 334719 342713 346709 351705
      357698 364690 371683 378673 387655 392651
 0.50 516264 516262 514260 513259 512257 511257 510255 509254
      509253 508254 509256 510258 510260 511260 512263 514264
      515266 516264
 0.50 346127 344126 343128 346128 346127
 1.00 451679 451671 450669 445664 441664 436667 429670 423668
      420664 418657 415650 413649 410650 405652 401657 395668
      389677 385683 384686 384691 387707 387715 389723 391729
      393736 393746 395750 397752 401753 407752 414749 419745
      427738 434727 439716 444705 447700 453692 451679
 1.50 444681 442674 437675 431680 429686 428688 425689 418688
      413685 410681 409676 407674 405674 397680 393690 392713
      393721 396726 398730 397735 398743 401746 405747 411745
      415743 419739 424731 429722 432711 434707 435701 436696
      440692 443686 444681
 2.00 426705 424698 421698 420700 413703 408707 406709 404708
      403705 401702 400699 398701 398712 400716 402718 404723
      403729 401736 401739 403740 408743 412740 416736 417733
      417729 417724 419721 422717 425711 426705

24HR QP VT 29/00Z
 0.01 475589 485598 497619 503639 503653 501663 498678 494687
      484703 472723 467732 463738 459744 455749 449756 436769
      429769 424768 419769 415767 414760 417756 422751 428752
      431749 430745 430741 428738 426737 423739 415744 413746
      408748 402751 397751 393749 390746 385743 380743 377743
      371743 364744 359743 355742 354737 352725 352719 353715
      357711 362708 369702 386693 393690 396686 400682 402678
      405673 406668 422628 444597 475589
 0.01 537164 538151 536145 533139 532132 528119 527113 527106
      528100 529091 527084 525080 522076 520071 522060 523047
      523042 522039 522030 521022 518009 515994 515986 514980
      514961 515936 515916 515897 513894 513889 513881 512874
      510866 509861 505856 505849 501844 499841 495840 492838
      488838 473840 468842 463846 461850 460855 465865 469873
      469876 471881 470886 468887 468895 470900 472903 476909
      475917 470929 471938 472943 475956 475970 475978 474983
      473992 472001 473014 479029 485038 492046 495058 497064
      500069 501075 501084 500098 503109 512134 516146 515151
      511152 508157 506163 499170 502178 504186 502202 498207
      493209 483206 478207 474209 471212 467212 459214 444223
      435247 439246 443242 446240 452240 455240 458240 459237
      456234 458230 462227 466226 472226 475225 480222 487224
      498230 509212 513210 514205 513202 515197 519195 525188
      529181 537164
 0.01 491139 489137 487135 486133 483130 481129 479130 476131
      474133 474136 475137 479137 482139 485139 489140 491139
 0.01 485161 482157 478157 475154 471150 468147 466144 463143
      464149 465152 465156 468160 469168 475170 481170 483168
      483163 485161
 0.01 456110 457098 456089 455082 452077 449072 444068 435064
      430059 428056 426055 412054 405053 400055 393060 389061
      388066 385072 377080 376083 378087 380093 381097 384095
      384092 387091 391092 395098 395107 390111 388115 384120
      382124 384127 387124 391124 395130 397136 395141 393143
      375145 371147 373150 376150 379149 381151 385154 389159
      387164 387171 385173 382172 377168 375169 374173 367172
      362170 364175 366179 364185 365189 374191 380196 383200
      389202 395201 400199 403197 407194 419190 421188 423184
      424176 428171 430165 428153 438157 443154 445148 444142
      447135 451122 456110
 0.01 434088 434078 433074 431073 429071 424070 422072 419076
      419081 418087 416090 415096 416101 419103 422102 426101
      425098 422091 421083 426087 431089 434088
 0.01 405095 406091 407086 406082 402083 402086 400088 398092
      397094 397097 399099 401102 402104 404102 404098 405095
 0.01 394798 393795 391793 388794 386796 384798 383801 381802
      380805 378807 378812 380812 382811 385809 387807 389804
      390802 392801 394798
 0.01 364820 361820 360823 358825 356827 355829 353831 351834
      351837 353839 354839 355837 357833 358830 359828 360825
      362823 364820
 0.25 477606 492626 496642 495658 492669 489674 485679 482681
      476682 466681 457681 452684 448688 442696 437700 433702
      427703 424706 419709 413712 407712 405710 406704 408698
      412689 419681 422677 424672 427660 429655 429649 428642
      439622 451611 477606
 0.25 507931 509926 508921 505914 502908 499903 495900 490898
      489902 489907 490915 493921 496926 500931 505933 507931
 0.25 446111 445105 443101 439099 436102 430108 423111 415113
      407111 407115 408119 416125 426125 432121 438114 444113
      446111
 0.25 418159 419156 418155 416155 416156 415158 415160 415163
      416163 417161 418160 418159
 0.25 410068 410067 408066 407066 405067 405068 405070 406071
      408071 409070 410069 410068
 0.25 400716 398713 395714 391715 388716 384717 381718 379719
      377721 379723 381725 384726 386726 389726 391725 394723
      396721 398719 400716
 0.50 491638 487628 485622 482619 480618 478618 476621 469628
      467632 467639 468650 474654 479655 481657 485662 487663
      490660 491654 490646 491641 491638

$$




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