Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 252102
QPFPFD

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


PRELIM 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

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 569981 566967 564956 562949 560942 557936 551926
      548922 545918 536909 533907 533903 534899 534893 533874
      533870 531867 531859 529851 526845 524842 522841 519839
      516840 504841 499844 494845 488848 482850 468853 447860
      443860 441863 436864 424871 420874 417878 413882 411887
      408900 410907 411911 413914 417917 422919 426921 432921
      438923 444923 453935 469947 479952 484953 486957 487962
      491967 495970 503975 515981 525987 529990 532995 536998
      539003 546012 555018 560015 563011 567007 568002
 0.01 531235 533230 534224 536216 538212 539205 540197 539188
      536182 534180 533177 534171 531164 527157 524152 510146
      504146 497146 491148 491152 492156 495164 496166 499168
      501170 506172 509174 511178 511183 512187 515192 520210
      521218 524225 524232 522235 519244 516244 515241 512236
      510232 506232 504244 504253 503264 501278 498287 491301
      489304 487308 485312 484318 484320 486322 489325 494327
      499325
 0.01 314697 308704 301710 289724 272741 264759 259768 254776
      248784 243790 236798 235810 233817 236818 240818 242821
      241823 241827 238836 242846 243849 245849 249848 254846
      255844 257847 259853 262857 263861 261864 262871 266874
      268876 271876 276873 279869 290854 294846 296841 295836
      321798 327790 330787 334784 341787 348791 353793 357798
      356803 357805 357809 345831 341842 336850 334855 336859
      331866 328870 326875 325880 328883 345882 350886 354890
      357893 359898 365905 371912 377915 380913 380911 383906
      385893 388877 391872 396867 403861 408853 413843 415832
      417818 418811 420806 433783 434771 435758 430737 428731
      426724 423715 421708 416696 413689 412682 408668 406661
      403658 397653 391655 387657 380660 375663 364669 353675
      347678 342681 324690 314697
 0.01 224086 212094 211113 218134 220136 224140 235150 247158
      258164 271169 282170 289168 300163 307162 310161 313163
      323170 330174 335178 339185 340188 343193 347193 347188
      351186 356185 359183 352181 350180 349178 350173 352169
      352164 351155 348148 345143 342137 345137 348139 352141
      353133 348127 343120 329098 323085 319077 315071 313066
      308060 304057 297056 294056 292060 291066 279055 269048
      265045 258043 250042 240042 236046 235053 238060 242064
      252071 257076 262082 267086 273090 277095 278098 278102
      275108 272109 269109 253103 247100 240096 232090 224086
 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 419768 417764 411759 405755 401753 397756 394763
      389771 385777 379783 375790 372797 370801 371804 374808
      376812 381818 388822 392828 399832 404826 408817 412810
      415801 417792 420783 419776 420773
 0.25 410721 410714 409707 406697 402684 400679 398673 392667
      388666 383668 373673 365678 352689 337701 330707 323712
      314718 309724 298737 293744 287753 285769 285775 286781
      288789 293795 297797 302797 306798 311795 318789 329777
      341763 347757 353752 362746 371742 376741 380742 385748
      390750 393750 398748 401748 402745 407734 409726 410721
 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 331143 325131 319123 316120 311117 300113 295114
      290118 290123 291128 292134 292138 290139 279134 274132
      268132 260137 250142 248145 252148 259150 266151 277151
      282150 288148 292146 298146 306147 312149 319155 325163
      329163 331159 332153
 0.25 287818 287816 286815 284816 283817 283818 282819 281820
      281821 280823 281825 282826 283825 284825 285823 286821
      287819 287818
 0.25 274075 274074 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 402715 402711 402706 399699 396691 392684 388679 384676
      380676 376677 370681 360688 349697 329714 321723 317729
      314735 310746 307753 306759 309766 313771 315773 320773
      325769 331766 336763 346754 356746 369740 381734 394731
      398728 400724 402715
 0.50 409775 407771 405769 403769 400769 398771 396773 395775
      393778 393782 393787 395789 398789 400788 403787 404784
      406780 407778 409775
 0.50 312137 311135 309132 307131 306128 304126 302124 299124
      298126 298128 300131 301133 304136 306138 308139 311139
      312137
 1.00 383720 383714 382710 377704 371702 367701 362703 356706
      350711 339721 337723 336726 338734 328744 328749 330751
      339749 345748 352745 363737 371734 377730 382725 383720

24HR QP VT 28/00Z
 0.01 328701 334691 353651 385616 423588 468600 486620 490639
      491652 484681 483690 480696 475710 469721 464730 461736
      456743 447753 439760 433763 436770 441784 437792 428802
      419807 411808 406808 403807 390812 380818 376821 370822
      367822 367825 366834 367839 368842 372848 375851 380854
      390858 417856 420858 426860 431861 439860 452860 462853
      473848 478847 481844 489843 496840 499840 502841 506844
      509851 510859 510868 509877 509882 508885 504888 499891
      493891 487892 484894 483898 484908 485912 486917 486923
      484926 482931 476917 471913 465913 463910 460911 454911
      446911 443911 440909 432904 423897 419894 411894 406892
      402890 400887 395883 391879 386875 381873 370869 360865
      355861 353857 352854 351851 349849 347842 348837 351831
      359819 369813 373812 374808 376803 377799 375796 371791
      365780 362774 362769 360765 357761 354760 351762 349767
      349774 353779 357786 360793 357795 346794 339793 332794
      325797 321797 307796 304794 301794 297791 294786 290783
      288781 287777 285773 285768 284764 286760 287755 290749
      292746 295744 296741 299736 306726 314717 328701
 0.01 539199 539191 537185 532176 528166 520159 517155 514154
      513156 512164 512169 509169 506169 505170 507175 508188
      509190 509196 506202 505207 505213 503214 500212 497208
      493206 490206 485204 481206 474210 470213 465214 459217
      455221 455224 457226 457229 455231 452232 446233 443236
      436242 430251 426261 425266 429265 436260 444252 447250
      451249 461249 462252 461255 462258 469266 473268 478269
      480268 483269 486274 491282 495287 501289 505290 509286
      515279 520270 522262 523257 521250 523246 527244 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 435145 436137 437128 434126 432121 433116 436112 437107
      436104 428104 423107 421110 420114 418116 413115 413118
      415120 419123 421130 416136 413140 410141 405141 401143
      397144 394141 390137 389132 391128 396127 405128 406122
      403118 398117 394113 390111 387112 382112 379114 372117
      367118 362116 358114 355111 352105 358088 351083 339082
      333077 326072 321071 317067 312060 307053 304050 299050
      294052 293056 297063 302068 309073 312078 310084 309087
      306089 303091 301094 301100 299103 297103 293104 281113
      288119 297121 303123 308126 310130 312134 317140 320143
      322147 322153 322159 323165 326167 328176 329185 331198
      330203 333208 336214 340217 345219 350218 352222 353226
      356228 358225 360219 363216 365211 365204 368201 370200
      376201 379204 395213 404219 403225 405227 410228 413224
      414218 412216 407217 403213 402207 403203 405195 408192
      413188 417186 420183 425174 430167 432163 432159 431153
      432148 435145
 0.25 378656 388638 407619 429607 452609 473625 475633 477638
      479647 479654 477666 473680 470691 465701 459710 447729
      439738 432744 424752 416759 407764 397765 389765 384764
      380763 377760 374752 374746 371739 367737 361738 357741
      350748 342768 338772 331773 320774 310770 307766 305761
      305753 306747 311738 317729 321722 325716 329711 335704
      342697 350691 355687 358682 364674 378656
 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
      497223 494223 494228 496235 502246 504252 505260 504265
      502264 497261 494262 493264 495270 501273 506274 511272
      515269 517267
 0.25 408159 408157 407155 407154 406153 404153 402155 401157
      400159 399162 399164 401166 401165 403163 404163 405162
      406161 407160 408159
 0.25 400169 399166 399164 399166 398168 399170 400169
 0.25 372190 372188 371186 370184 368183 366183 365182 363183
      361183 361184 360186 362187 364188 364189 365189 367190
      369191 371191 372190
 0.25 373152 371146 370144 371140 369135 365132 355126 350118
      347114 344111 341109 339112 337117 339123 339128 342133
      345136 349139 354139 358141 364141 370151 373152
 0.25 350185 348185 345182 344180 343177 342174 340175 340178
      340181 342184 343186 344189 345193 346196 348192 349187
      350185
 0.50 398636 413626 434620 453622 463632 466636 469643 468655
      468663 468672 466682 464690 461696 452708 436731 427743
      422747 417751 410754 402757 394758 387758 384756 382751
      384743 385734 384729 382725 380722 376721 370720 364717
      360711 359703 361696 363690 367685 377673 381667 384662
      387656 390651 398636
 0.50 516264 516262 514260 513259 512257 511257 510255 509254
      509253 508254 509256 510258 510260 511260 512263 514264
      515266 516264
 0.50 344726 344718 340715 336717 332721 327729 322737 319742
      317747 318753 322756 328764 333764 337762 340756 341751
      342739 344726 344726
 1.00 457680 452665 447661 441663 434664 428661 420654 416649
      410650 402653 397659 395665 393671 389676 385682 384684
      385689 386705 388714 391720 393726 392734 391742 392747
      397750 404748 411746 417743 426734 433725 439714 443707
      446702 454692 456685 457680
 1.50 440682 440674 435676 429682 423683 420681 416674 411664
      409662 407664 404667 400676 396684 393704 392708 393711
      395715 397720 399726 397736 398743 402743 408742 412739
      418733 424727 429720 433711 436703 440682
 2.00 428707 427699 424694 419693 415691 408684 405684 404689
      403698 402702 400704 399708 400711 403717 404724 402737
      406735 408733 409730 412727 417725 422721 424718 426711
      428707

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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