Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 291101
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
600 AM EST THU JAN 29 2015


FINAL DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION
VALID JAN 29/1200 UTC THRU FEB 01/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


UPDATE

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

DAY 1

SOUTHWEST

FAIRLY WELL DEFINED HEIGHT FALLS APPROACHING THE NORTHERN BAJA
PENINSULA DAY 1 WILL BE TAPING A BROAD REGION OF ABOVE AVERAGE PW
VALUES---2 TO 3+ STANDARD DEVIATIONS ABOVE THE MEAN--CURRENTLY OFF
THE BAJA PENINSULA AND PUSHING THESE ANOMALOUS PW VALUES
NORTHEASTWARD INTO THE SOUTHWEST.  THE COMBINATION OF DIFFLUENT
UPPER FLOW AHEAD OF THESE HEIGHT FALLS AND STRENGTHENING EAST
SOUTHEASTERLY LOW LEVEL FLOW IN THIS INCREASING PW AXIS WILL
SUPPORT INCREASING PRECIPITATION COVERAGE AND INTENSITY DAY 1
ACROSS LARGE PORTIONS OF AZ---NM AND INTO FAR WEST/SOUTHWEST TX.
WIDESPREAD MODERATE PRECIPITATION TOTALS LIKELY ACROSS THESE
AREAS---WITH ISOLATED HEAVY TOTALS POSSIBLE IN THE FAVORED TERRAIN
REGIONS OF CENTRAL TO SOUTH CENTRAL AZ AND SOUTHWEST NM.

GREAT LAKES---UPPER OH VALLEY---CENTRAL APPALACHIANS INTO THE
NORTHERN MID ATLANTIC---NY STATE INTO WESTERN NEW ENGLAND

SEVERAL AREAS OF SHORTWAVE ENERGY EXPECTED TO ROTATE THROUGH THE
MEAN UPPER TROF CENTERED FROM THE GREAT LAKES INTO THE OH VALLEY
DAY 1.  THE LEAD AREAS OF SHORTWAVE ENERGY IN THE MORE SOUTHERN
STREAM OF TWO WILL HELP PUSH WARM ADVECTION PRECIPITATION FAIRLY
QUICKLY EASTWARD FROM THE EASTERN LAKES/UPPER OH VALLEY
REGION---INTO LARGE PORTIONS OF THE NORTHEAST THURSDAY.  THE QUICK
MOVEMENT WILL KEEP PRECIP TOTALS ON THE MODERATE SIDE---WITH AREAL
AVERAGE .10-.25"+ AMOUNTS DEPICTED AS PER MODEL CONSENSUS--WITH
POTENTIAL FOR MODERATE TO HEAVY SNOW TOTALS FROM THE EASTERN
LAKES---CENTRAL APPALACHIANS AND INTO NORTHERN NY STATE.  A MORE
NORTHERN STREAM OF SHORTWAVE ENERGY WILL BE DIVING SOUTHEASTWARD
INTO THE MEAN TROF POSITION THURSDAY---HELPING TO SHARPEN THIS
TROF TOWARD THE END OF THE FORECAST PERIOD FROM THE GREAT LAKES
INTO THE OH VALLEY.  LAKE EFFECT SNOW SHOWERS WILL INCREASE FROM
WEST TO EAST ACROSS THE GREAT LAKES IN THE WAKE OF THE AMPLIFYING
TROF.  THIS AMPLIFYING TROF WILL HAVE MORE SIGNIFICANT POTENTIAL
IMPACTS DAY 2 OVER PORTIONS OF NEW ENGLAND WITH RESPECT TO
ADDITIONAL HEAVY SNOWS.


DAYS 2/3...


...SOUTHWEST/SOUTHERN ROCKIES/SOUTHERN TO CENTRAL PLAINS...

A LARGE SPRAWLING CIRCULATION WILL MOVE EASTWARD ACROSS THE
SOUTHWEST ON DAY 2.
MOISTURE TRANSPORT FROM THE GULF OF CA INTO THE SOUTHWEST IS
ADVECTED INTO ARIZONA.
LARGE AREAS OF 700 MB CONVERGENCE AND ASCENT OCCURS UNDERNEATH 300
MB DIVERGENCE MAXIMA OCCUR ACROSS THE SOUTHWEST.  THE STRONGEST
ASCENT INTO SOUTHEAST AZ AND ADJACENT MOGOLLON RIM PRODUCE THE
HIGHER FORECAST PRECIP AMOUNTS.  THERE ARE MINIMUM AMOUNTS ALONG
THE SHADOW AREAS TO THE LEE OF THE MOGOLLON RIM.
MANUAL QPF BLENDED THE ECMWF/UKMET/NAM/GFS/21Z SREF MEAN AMOUNTS.

THE MID-UPPER LEVEL RIDGE BUILDING ACROSS THE NORTHWEST INTO THE
NORTHERN ROCKIES FORCES THE TROUGH/CIRCULATION SOUTH ON DAY 3 INTO
MEXICO/BAJA CALIFORNIA. THE ASCENT OVER THE SOUTHWEST WEAKENS WITH
STRONG VERTICAL MOTIONS SHUNTED DOWN IN MEXICO...WITH GRADUAL
WEAKENING OF 300MB DIVERGENCE MAXIMA OVER THE SOUTHWEST.
CONSEQUENTLY...QPF AMOUNTS ARE LOWER SAT/SAT NIGHT.

IMPULSES FROM THE TROUGH WILL BEGIN TO EJECT EASTWARD TOWARDS THE
END OF DAY 2.
A MOISTURE FEED SET UP ACROSS CENTRAL TX WITH ASCENT COMMENCING
NEAR 700 MB AND SHOWERS INCREASING IN LOW LEVEL CONFLUENT FLOW
FROM SOUTHWEST TX TO CENTRAL AND NORTHERN TX SAT...CONTINUING
NORTHEAST ACROSS OK AND THEN EASTERN KS/WESTERN MO.

THE MODELS SUCH AS THE CANADIAN/NAM/UKMET INGEST THE LOW LEVEL
MOISTURE IN THE MID MS VALLEY INTO A MORE AMPLIFIED NORTHERN
STREAM WAVE AND SFC REFLECTION.  THIS RESULTS IN A MORE NORTHWARD
EXPANSION OF PRECIPITATION WITH HIGHER AMOUNTS THAN IN THE ECMWF.

THE MODELS HAVE HAD TROUBLE RESOLVING THIS NORTHERN STREAM WAVE
AMPLITUDE AND TIMING.  CONSEQUENTLY...ONLY A FEW ADJUSTMENTS WERE
MADE WITH THE 12Z ECMWF ENSEMBLE MEAN BLENDED WITH THE 00Z ECMWF
AND 00Z GFS TO DERIVE THE FINAL QPF.
ON DAY 3...THE QPF GREATER THAN .5 INCHES COVERED MUCH OF WEST
CENTRAL TEXAS ACROSS OK INTO EASTERN KS...WHERE THE 00Z ECMWF
SHOWS A 300 MB DIVERGENCE MAXIMA SAT NIGHT.

...NORTHEAST...

THE MID LEVEL TROUGH ACQUIRES A DISTINCT NEGATIVE TILT AS IT
APPROACHES THE NORTHEAST COAST. AS IT DOES SO...A PARENT LOW
PRESSURE WITH ONE CENTER WILL MOVE FROM THE GREAT LAKES TOWARD NEW
YORK WHILE A SECOND AREA OF LOW PRESSURE DEVELOPS ACROSS SOUTHERN
NEW ENGLAND AND THEN INTENSIFIES OFF THE NEW ENGLAND COAST. THE
CYCLONE INTENSIFIES AS AN UPPER LOW DEVELOPS WITHIN THE UPPER
TROUGH.  AS THE UPPER TROUGH CONTINUES TO AMPLIFY...THE AREA OF
PRECIPITATION EXPANDS ACROSS MAINE. MUCH OF THIS PRECIPITATION
WILL BE IN THE FORM OF SNOW.  SEE THE HEAVY SNOW DISCUSSION AND
PROBABILITIES FOR ADDITIONAL DETAILS.

LIQUID EQUIVALENT QPF VALUES NEAR AN INCH ARE POSSIBLE IN PORTIONS
OF DOWNEAST MAINE  AS THE SURFACE LOW DEVELOPS IN THE GULF OF
MAINE AND DRIFTS TOWARDS NOVA SCOTIA.
THE CYCLONE IS EXPECTED TO WRAP UP AND OCCLUDE ON FRIDAY NIGHT
INTO SATURDAY WITH THE HEAVIEST QPF IN A BAND OF DEFORMATION NORTH
OF THE CIRCULATION.  MANUAL PROGS USED A BLEND OF THE 00Z
GFS/ECMWF/UKMET/NAM QPF.  ON SAT THE EVENT WINDS DOWN AS LOW
PRESSURE MOVES AWAY INTO THE CANADIAN MARITIMES.

ORAVEC/PETERSEN

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


24HR QP VT 30/12Z
 0.01 544782 544770 543766 542764 537748 531735 529728 529723
      527716 524710 519705 516699 513693 510690 504683 493681
      487680 481682 475682 469683 462684 458684 455685 452683
      446684 444683 440684 432687 412696 406700 400702 390709
      378714 369719 356725 351728 347732 333748 329753 327757
      324771 320783 317793 308818 306823 305829 306844 306849
      309854 315854 320853 325841 329830 334818 335812 337805
      341795 344783 353759 358748 363739 369735 376734 381737
      382741 380743 378757 380761 385763 387765 386768 384774
      382780 379785 376791 373795 366803 362807 359812 352822
      350828 351835 352842 355843 355848 355853 357859 362861
      370860 378860 382857 389850 393849 395851 398852 399855
      403862 407866 416870 420872 423872 424870 430867 435869
      442868 447866 455866 459870 461876 461885 461893 463901
      466905 470901 473895 475890 476882 478875 479866 482862
      494858 514848 518844 521839 527828 531814 533800 537795
      541791 544782
 0.01 381122 382115 383108 379100 376095 375091 376084 377082
      375071 370064 368058 366055 360050 353044 348037 336027
      327023 323022 321024 315031 311039 305045 298050 286062
      280066 274073 271082 269091 267095 269098 273106 275109
      280111 285116 291123 295126 298127 308126 311129 314133
      319139 326144 333150 343152 348152 352151 358147 365140
      371133 381122
 0.01 330170 327165 322160 319157 315157 312154 308153 304153
      302154 305161 303165 302169 304172 307173 314178 321180
      323179 325174 330170
 0.25 518753 518744 516738 508734 507731 506726 504722 496717
      494712 489712 478715 472716 467719 459725 449743 446744
      444739 440735 435735 431738 427743 427749 428754 430762
      430769 427774 423777 419778 415778 409779 405781 397787
      389792 381799 378804 376808 377814 379817 383820 388822
      399822 409822 413820 417817 425813 430811 435812 441812
      443813 443816 442823 441827 443831 447834 452832 462827
      468821 477815 484811 492805 499797 504787 510780 514774
      515766 518753
 0.25 358118 358111 357106 352097 348087 345076 343070 341065
      336058 331055 328057 325063 322067 315071 305076 298082
      295086 293092 292097 293102 297105 302108 305111 311113
      322113 328113 333116 339124 341128 344132 347133 350132
      353128 356123 358118
 0.50 485773 485771 483769 480767 477767 476768 474770 474775
      474780 475783 479783 482781 484780 485776 485773
 0.50 455798 455796 455793 454791 452791 450790 449791 448792
      447795 448797 449798 451798 453799 455799 455798
 0.50 410798 410796 409796 407797 407799 408799 409799 410798
 0.50 343111 344104 343098 340087 338082 334077 330076 327080
      322082 316082 311082 306085 304088 302093 301100 304104
      309105 314105 325103 330105 334108 338111 343111

24HR QP VT 31/12Z
 0.01 439631 446634 451634 456632 462630 467631 470630 475631
      481631 487635 492643 494646 496652 497661 500662 504662
      512668 517674 518679 518683 517687 515692 512701 507709
      501713 498716 493718 487721 484725 478732 454750 444765
      441769 439773 436779 435784 435787 432790 429793 428797
      422804 417809 408810 403804 400802 397805 394807 391810
      388815 382818 374819 366824 362829 357837 353837 355833
      358823 363816 372806 384795 418778 421772 420762 423754
      429748 430744 430740 428738 422733 408720 383738 366737
      357737 351740 348743 335754 330758 328760 324758 317755
      311760 304761 300760 296752 296745 296736 297726 300717
      307700
 0.01 522266 516258 513255 511250 507242 502241 502244 504249
      503254 501258 497255 493253 491255 491261 493265 496269
      498274 500278 503281 506285 509285 513282 515278 516275
      519275
 0.01 545057 545047 544038 539023 532013 529010 527004 525997
      523994 525991 529984 532978 536968 536963 538960 536952
      534947 531941 527933 525925 525915 523913 523907 521892
      517876 515871 512869 510870 507869 507864 507856 500847
      491843 484844 480844 478847 475847 473850 470855 462856
      455856 452857 450860 450862 454862 457862 460864 454867
      452870 452879 454884 460896 464901 467905 467908 470915
      470925 471930 474937 481947 483953 486962 490974 492980
      495985 501995 503003 506011 512021 514027 517033 523044
      526050 528058 530066 532071 536073 539073 540070 544063
      545057
 0.01 525193 525187 524183 517177 512171 513168 516167 521162
      526154 528145 528140 527135 527123 524112 522104 520096
      513076 511069 507062 499046 491033 485029 482027 479029
      479040 480049 481060 483071 486090 489111 494127 500167
      502176 503181 506185 507179 509180 512187 519195 523195
      525193
 0.01 449816 447814 444812 440813 435815 430816 427817 427824
      431826 434826 439825 443822 446820 449817 449816
 0.01 222070 225078 231085 239090 243093 246096 250101 253104
      251107 244112 241114 239118 238123 239127 242134 248135
      255134 263132 276129 281130 283133 289140 294145 298148
      299151 297153 295155 295161 297164 302168 305170 310171
      314172 317171 326172 331172 335174 350184 354186 359188
      369185 375181 380174 383167 387159 391149 400146 404142
      405136 405130 402127 400125 401122 404119 407118 410115
      412096 407091 404086 404079 405070 404063 404056 403051
      399046 389045 381045 377037 376034 379031 384024 388011
      394004 402991 403987 404981 405976 404970 400963 397959
      393956 389953 386949 383947 379947 348960 341964 335969
      330972 325974 314974 306975 299978 292982 284985 276988
      268992 264996 262000 260010 262016 262027 259036 253040
      239042 227043
 0.25 509275 510273 510270 510269 508268 507269 506269 505271
      504271 503273 503276 504276 505279 506279 508277 509276
      509275
 0.25 516135 516131 515127 514124 513121 511118 509116 508120
      508125 508129 508133 509138 509141 512142 513141 515137
      516135
 0.25 331687 328695 329700 328705 321719 318727 316732 315738
      317743 320741 327737 334732 344726 357717 376708 382704
      391700 401699 406700 410702 421714 427718 436721 440722
      444721 449720 454720 458718 462716 470709 475701 477691
      477681 476677 475669 472659 471652 468649 461647 451647
      444646 435649 430650 426650 415648 408647 400647 393648
      386649 379651 375654
 0.25 391112 392103 392094 389080 386068 382063 379060 370054
      367050 364041 366027 370014 369011 366010 362010 351004
      340001 329002 304008 297013 290021 286032 282038 279044
      275047 270050 261053 250056 246059 243061 242065 243072
      245077 250085 266103 272108 281114 291120 297123 306125
      313126 317128 321130 325134 329145 332151 337156 346161
      352163 358164 362161 366158 375148 381140 387131 391112
 0.50 467687 465677 463668 460661 456657 449655 443655 434665
      428671 425676 425686 423691 425703 428707 435710 440711
      447711 454708 459704 463700 466692 467687
 0.50 383678 382676 379675 376675 368679 359683 351688 344692
      340698 346698 351697 359693 366690 374686 381681 383678
 0.50 377125 376115 377108 379101 380096 378092 377089 375082
      375077 373073 368069 364067 356062 352055 344034 341026
      334021 330018 324018 314021 306025 300029 294036 287045
      281051 276055 257063 254065 252068 252075 253079 258086
      265094 277104 285110 294116 299118 303119 312119 324120
      329122 333127 340143 343147 348149 355149 359147 366141
      370136 375130 377125
 0.50 355093 356087 356082 354077 351073 349069 346067 342070
      341074 341080 341086 342090 345094 347098 351097 355094
      355093
 1.00 448687 448682 447679 444677 441678 440680 438683 437688
      437690 438695 440697 442698 445696 447694 448690 448687
 1.00 342109 341103 338097 336095 334090 333085 330080 327081
      326086 326092 322095 316094 311092 293085 289083 286078
      280073 275071 271071 264076 265081 268085 275091 283096
      290102 297108 300110 306110 310110 315107 319106 324108
      329109 335111 342109


24HR QP VT 01/12Z
 0.01 482616 488619 492622 496628 498631 501637 502646 502655
      503661 505663 510668 514676 513681 511685 508687 506689
      501690 495689 490688 487687 483689 476693 465700 450706
      448705 444706 437707 431708 426709 423711 415713 409712
      404708 398703 396697 395689 397681 400674 411666 415664
      417660 417657 420653 421650 425650 431650 438646 444639
      450632 453629 457625
 0.01 529242 530234 531226 530210 527198 524194 519195 513201
      512206 513209 515215 514220 511222 508227 507231 504228
      498225 491232 483236 480239 477245 478251 480255 483260
      487265 489270 492274 493288 495294 499296 504295 509295
      512291 514287 519274 522266 524261 526255 528245 529242
 0.01 224058 232073 237079 241086 245092 250096 261105 276115
      280118 283122 284135 286156 287160 292161 296160 301163
      308167 318169 322169 324166 326161 327154 329151 332149
      339148 346145 351146 354144 363141 365140 368140 373138
      379135 385129 396115 402090 403076 402067 399058 397053
      395049 393029 397021 402015 405013 408010 410005 413001
      422985 425985 428990 430004 433017 435028 438038 444042
      449047 452051 454056 454060 453065 453069 455074 458082
      457089 459093 476127 483136 487138 490142 492148 495152
      500158 503162 508162 511162 513165 520171 524172 527170
      526163 523155 526148 528145 528139 529130 528127 528122
      526110 519091 512071 503049 499041 496033 486017 470990
      464974 454955 454939 454930 457923 460913 462908 465905
      477892 481885 485876 493863 497855 500847 504839 507828
      506810 506808 503807 499806 496806 494803 492798 488790
      486786 482781 479779 475780 470781 467784 464785 460788
      453794 448799 441812 437819 436824 433827 431831 429836
      426846 425852 424854 422853 417853 415853 413850 408842
      403832 399823 399820 396820 391817 388815 384816 381818
      376819 374820 372825 369834 364851 359866 356876 350884
      346891 336895 311896 306896 303896 300895 295899 288904
      282908 282912 280916 277925 272941 266956 263965 261975
      260982 258986 255994 254998 253002 251006 247014 239029
      235035 234039 227047
 0.25 494668 494663 492658 489649 486643 482638 470637 463639
      457643 450646 444651 439655 435660 434667 437676 441680
      447681 461681 474680 480680 488678 492673 494668
 0.25 487086 487083 486083 485080 483078 483080 483082 483083
      484085 485086 486088 487086
 0.25 410935 410924 407912 403904 398901 387900 382902 379906
      373914 366921 360927 353933 341941 326951 319956 309962
      294970 283979 275986 271993 267003 267009 267016 268025
      270030 273034 279037 287041 291043 294047 298057 302065
      303071 301078 299081 294081 284081 278077 272073 266066
      262063 257061 251060 248062 245065 244069 244072 249079
      255085 267094 279105 286112 295119 301125 306127 312128
      316128 320126 323124 326123 334118 338115 340112 343098
      345085 345076 345072 340070 336071 333073 331076 329081
      327085 326085 325081 323078 323071 325065 325059 328055
      332053 336055 341056 346056 348060 351063 355062 357060
      361061 363058 365053 364043 362037 360032 359027 360023
      362018 367010 373003 383994 396982 402975 405969 407963
      410950 410935
 0.50 485658 484654 482649 474644 467644 459647 451652 447655
      445658 444663 445668 448671 453673 461673 470671 478671
      481670 484666 485658
 0.50 398952 399946 397943 393939 390937 386937 380938 377939
      368948 360950 355951 350952 338956 325963 315972 309976
      303980 291986 286991 282998 281002 282007 285012 290016
      298020 310026 314027 318027 327025 332023 338019 343015
      349009 365985 369979 373974 379971 387968 391965 394962
      397957 398952
 0.50 266080 265078 263076 262074 261074 260072 259072 258071
      256070 254070 253071 253073 254074 255075 256076 257077
      258078 259078 261079 263080 264081 266081 266080
 1.00 342991 342989 340986 335982 330981 324983 321988 317992
      315996 314000 315004 320006 326004 331001 335999 340995
      342991

$$





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