Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 280701
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
301 AM EDT THU JUL 28 2016


PRELIM DAY 1 QPF DISCUSSION
VALID JUL 28/1200 UTC THRU JUL 29/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

...EASTERN U.S. FROM THE LOWER MISSISSIPPI VALLEY TO THE MID
ATLANTIC...

MODERATE FORCING WILL TEND TO FOCUS A SWATH OF 1.0 TO 2.5 INCH
AREAL AVERAGE PRECIPITATION FROM TENNESSEE TO NEW JERSEY AS RICH
MOISTURE IS SWEPT UP AHEAD OF AN ADVANCING TROUGH. THE TROUGH
ORIGINATED AT TROPICAL LATITUDES...BUT WAS BEING STEERED AROUND A
HIGH CENTERED ALONG THE SOUTHEAST ATLANTIC COAST...AND WAS SET TO
JOIN THE WESTERLIES WITH SOME ACCELERATION EXPECTED TODAY. THIS
WILL INCREASE THE STRENGTH OF SOUTHWESTERLY LOWER LEVEL FLOW INTO
THE EASTERN TN/OH VALLEYS AND INTO THE UPSLOPE AREAS OF THE
CENTRAL APPALACHIANS. AT THE SAME TIME...FORCING SPILLS OVER INTO
THE MID ATLANTIC...INCLUDING MUCH OF SOUTHERN PA DOWN THROUGH
VA/MD AND EASTWARD...AS MID/UPPER SUPPORT IS ENHANCED WITHIN THE
ENTRANCE REGION OF A DEVELOPING JET STREAK. FORECAST SOUNDINGS
INDICATE A LOT OF HIGH CLOUDINESS WHICH MAY LIMIT INSTABILITY
ALONG THE PATH OF GREATEST FORCING FOR ASCENT...BUT THE LIFT
ITSELF WILL OPERATE ON A DEEPLY SATURATED ENVIRONMENT...AND EVEN
MINIMAL INSTABILITY WOULD BE ENOUGH TO LEAD TO SOME EFFICIENT
RAINFALL PROCESSES. HEAVIER SHORT TERM RAIN RATES ARE POSSIBLE A
LITTLE FARTHER SOUTH IN AREAS OF GREATER HEATING FROM EASTERN TN
INTO VA/MD/DE. ADDITIONALLY...A FEW SOLUTIONS POINT TOWARD A
REDEVELOPMENT OF HEAVY RAIN OVER SOUTHWEST PA THURSDAY NIGHT IN
THE DEFORMATION AREA OF WHATEVER CIRCULATION MAY CONTINUE TO EXIST
EMBEDDED WITHIN THE ADVANCING TROUGH.

MODEL QPFS DISPLAY SOME NORTH TO SOUTH VARIABILITY WITH THE
PLACEMENT OF THE AXIS...AND ALSO SOME DISAGREEMENT AS TO THE
EASTWARD EXTENT OF HEAVIER RAINFALL. THE GFS APPEARED TO SUFFER
SOME FEEDBACK IN ITS OMEGA FIELDS...BUT THE CONSENSUS TRACK OF THE
MID LEVEL FORCING IS SIMILAR TO THAT OF THE GFS...AND GIVEN THE
AVAILABLE MOISTURE...WOULD FAVOR EASTWARD EXTENSION OF HEAVIER
RAINFALL ACROSS SOUTHERN PA INTO NJ AND EVEN TOWARD LONG ISLAND.
WPC STARTED BY BLENDING THE PREVIOUS FORECAST TOWARD THE 00Z NAM
CONUS NEST AND 12Z WRF-NMM. THE RESULTING QPF HAS SUPPORT FROM THE
UKMET...WRF-ARW...AND TO SOME EXTENT THE 00Z ECMWF.


...CENTRAL PLAINS...

A FAIRLY WELL DEFINED EVENT IS PROGGED IN WNW FLOW ALOFT...WITH
RECENTLY ARRIVED FRONTAL BOUNDARIES FOCUSING A WESTWARD PUSH OF
DEEPER MOISTURE INTO THE CENTRAL HIGH PLAINS...AND PHASING OF
SHORTWAVE ENERGY COMING DOWN OUT OF MONTANA AND THE DAKOTAS. THE
NAM/GFS/ECMWF NOW SHOW SOME SIMILARITY IN PLACEMENT OF THEIR QPF
SWATH...WHICH WIDENS OVER KANSAS AND DIPS INTO NORTHERN OKLAHOMA.
IT IS NOT CLEAR THAT THERE WILL BE ONE LARGE FORWARD PROPAGATING
SYSTEM...AS THE SHEAR IS STRONG ENOUGH TO ALLOW FOR SUPERCELLS AND
SOME MIXED MODES...BUT COVERAGE SHOULD EXPAND WITH TIME THURSDAY
NIGHT...AND ALTHOUGH MOTION WILL BE QUICK...SOME HEAVY RAINFALL IS
POSSIBLE.


...MIDWEST/GREAT LAKES...

HEIGHT FALLS ON THE NORTHERN END OF THE AMPLIFYING MS VALLEY UPPER
TROF WILL SUPPORT A SEPARATE NORTHERN PRECIP MAX DAY 1 FROM THE
UPPER MS VALLEY EASTWARD TOWARD THE GREAT LAKES ALONG THE
ASSOCIATED NORTHERN STREAM FRONTAL BOUNDARY STRETCHING WEST TO
EAST ACROSS THIS AREA.  THERE IS MORE MODEL SPREAD WITH QPF
DETAILS ACROSS THIS REGION THAN POINTS FARTHER TO THE SOUTH OVER
THE LOWER MS VALLEY INTO THE MID ATLANTIC---LEADING TO LOWER
CONFIDENCE HERE.  THE IN HOUSE PSEUDO-BIAS CORRECTED ENSEMBLE MEAN
WAS FOLLOWED MORE CLOSELY HERE TO MITIGATE THESE DIFFERENCES WITH
AREAL AVERAGE MODERATE TO LOCALLY HEAVY PRECIP TOTALS POSSIBLE.


...NORTHERN NY STATE INTO NORTHERN NEW ENGLAND...

THE EASTERN EXTENT OF THE AFOREMENTIONED NORTHERN STREAM FRONT
WILL PUSH SOUTHEASTWARD ACROSS NORTHERN NY STATE AND NORTHERN NEW
ENGLAND THURSDAY. A NARROW AXIS OF ABOVE AVERAGE PW
VALUES..1.5"+...IN THE VICINITY OF THIS FRONT WILL SUPPORT
SCATTERED CONVECTION ALONG THE FRONT---WITH MODERATE PRECIP TOTALS
POSSIBLE FROM NORTHERN NY STATE INTO NORTHERN NEW ENGLAND.

BURKE/ORAVEC

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

24HR QP VT 29/12Z
 0.01 548080 549063 545054 539048 534047 529049 516061 502074
      496080 489088 485098 484111 486116 488120 485122 481122
      476121 474116 473110 473106 472098 471093 461089 458087
      458079 457073 458064 459063 462063 466065 475063 480053
      482048 483041 484035 483030 479027 474024 471023 468021
      468018 464012 463008 460003 453998 448997 446997 443995
      440988 437985 434987 431990 428994 426996 425994 422990
      417982 413974 407965 402957 397946 393939 386935 384935
      383932 384925 384915 376910 373907 371905 373902 380897
      385896 390896 393900 392905 396908 399908 403910 409911
      413912 417915 422922 424924 421926 417928 414939 414947
      415952 420952 423950 429945 435938 441933 447928 454918
      459911 462901 462887 458876 456874 451873 445874 440873
      442868 444862 445857 443851 441847 438845 435841 433837
      433823 430821 423822 420822 420816 420808 423799 426789
      428785 429782 431783 434785 438785 459753 458745 459737
      460726 462715 463708 466702 469691 472680 475669 477659
      477647 475634 474628 471625 469622 464624 429699 427705
      426707 422710 419705 416702 413700 409699 404700 394703
      389708 383716 381720 379725 380732 379737 372744 363749
      358756 352764 349769 348772 346776 349779 353781 356787
      358791 361792 363792 364795 363800 356817 352821 347822
      341828 330843 322859 316867 314866 314863 314856 313849
      312844 308834 307827 309820 307818 303814 295813 290813
      287816 286819 287823 291826 293830 299836 302837 302840
      300846 299849 300854 303859 304865 300865 296866 293870
      291874 285893 284905 284917 286921 288919 290920 294923
      298926 299931 297936 295945 291952 288955 284956 270968
      262972 262975 263977 264981 267984 267991 267997 270999
 0.01 270999 272002 270004 267006 263005 253998 246994 243993
      242994 242999 244001 249006 263025 264033 261039 257040
      253039 246037 237037 233037 231039 229046 230055 233063
      236067 241082 258098 266105 273109 281111 292119 298122
      305123 310119 313120 318121 323117 323112 325110 327111
      329112 330108 330103 329101 325096 315088 303081 290075
      283073 281071 280067 274055 270038 269035 273035 279037
      283037 286036 290033 289027 286022 281018 279016 282015
      286016 288018 291019 293018 295015 295010 295006 293003
      290997 291992 293989 301977 306975 309973 313975 317988
      324989 329986 332979 334971 336963 337958 339955 342950
      346945 353946 358942 362943 360947 357953 352965 348980
      346989 345996 346002 347004 351009 361018 364026 365034
      367042 368046 371049 378052 382052 383050 385047 387047
      390052 394057 400058 406056 409055 412058 417071 419070
      421067 419064 420059 421054 425054 432057 436064 439071
      440075 442079 445085 446088 443088 438084 435085 435090
      436093 442097 448100 452105 454109 453115 497149 502154
      505160 514171 517176 521181 527185 531181 535178 539171
      539161 537152 530138 526132 520126 514122 510116 510110
      512107 518104 527101 533101 538099 545090 548080
 0.01 386145 386143 383140 381139 377138 375140 373143 372145
      373147 373152 375154 378153 379149 381147 384146 386145
 0.01 376134 376132 377130 377128 377126 377125 375123 373123
      373125 374127 374130 374132 374134 374135 376135 376134
 0.01 379085 379077 375071 375064 372064 370059 372057 370055
      367050 361049 356052 354056 355061 355066 352072 347076
      343079 338080 334079 330081 328083 328087 332100 334101
      335106 334114 335122 335130 336133 340134 344133 347139
      353143 363137 359127 354122 353115 349101 350093 355089
      358084 361077 364074 367075 372080 374087 379085
 0.01 364159 365157 364156 363156 361154 360156 361157 362158
      364159 364160 364159
 0.01 324161 324158 321156 319155 315154 312153 308151 307150
      304151 304154 306156 309157 313158 315159 318161 322161
      324161
 0.01 315105 315102 314099 311098 307099 303100 299101 296105
      297109 301112 304114 306115 307113 309109 312107 315105
 0.01 287843 287837 285833 280825 269812 266810 262809 260806
      261803 268799 268793 266790 261789 256790 252792 249791
      245793 243797 239805 236813 236818 237822 243829 245833
      248835 252834 255832 258829 262831 275840 281846 285846
      287843
 0.25 522155 521150 518146 516143 514138 511135 506134 504140
      506145 508149 511152 514156 518159 520159 522155
 0.25 463670 462663 461658 458661 456665 451673 447680 443691
      441700 441706 444705 451700 454697 457692 460684 463673
      463670
 0.25 446724 446722 445721 443721 443723 442725 440725 440726
      439727 438729 438730 437731 438732 440733 441732 443731
      443730 444727 446726 446724
 0.25 451034 449027 445022 437012 432009 427010 423006 420001
      417993 414987 410984 406980 398970 395964 389961 383959
      375959 370961 365965 362970 359978 361985 364990 369004
      375015 380018 388020 393021 398024 410030 415033 419036
      425040 430043 442045 444041 448039 451034
 0.25 449904 447900 442900 439899 437897 428885 427880 426876
      426871 428867 429859 427851 422846 419846 416849 412854
      410861 412882 411891 415898 418905 420907 424909 431911
      436915 439916 443916 446908 449904
 0.25 423739 423734 421731 417727 413721 409715 408713 404713
      400718 396731 394737 390743 380752 377755 373760 371766
      375772 374779 372785 372795 370802 359823 352834 350841
      347848 345860 342866 339871 331881 327886 324892 320903
      316918 316927 316936 315939 317942 319944 320947 322954
      323956 327957 334949 337943 339935 340927 342920 344915
      348911 352906 354899 356892 360887 367876 370871 373868
      382859 390848 396837 401824 404811 407795 413782 416769
      420757 422747 423739
 0.25 312943 312941 310940 308940 307941 307942 306943 305945
      305946 304947 304949 304952 305953 306952 307951 308949
      308948 309947 310945 312943
 0.25 300091 295084 286081 277078 272073 271070 273066 273062
      270058 266051 258048 248044 240047 237049 236056 239063
      242072 246080 251086 255088 260089 264091 267094 272101
      277102 283101 290098 296094 300091
 0.25 275022 275019 274018 274017 273015 272015 271013 270013
      269013 267013 266013 265014 264015 265016 266017 267018
      268019 268020 270021 270022 272023 274022 275022
 0.25 254818 253812 253810 254804 250800 247804 245807 244811
      242817 242819 245823 247827 250824 252822 254818
 0.50 452681 450680 449682 447685 449686 451684 452681
 0.50 438038 436033 435030 435028 433025 430024 427025 425027
      425032 426036 428037 429037 433037 435038 438038
 0.50 438909 437906 436904 434902 432901 431900 430900 429901
      428902 429903 431904 433906 433907 434908 436909 438909
      438909
 0.50 419747 418741 416738 412735 411731 408720 406717 403721
      399729 396738 392745 387749 381755 378759 376763 377769
      380771 380773 378778 376781 375786 374792 374798 374803
      373806 369813 366821 361828 357836 357846 356852 355856
      355861 357863 354869 352873 352877 355878 359876 364869
      368864 371860 374858 380853 385846 389840 393833 397825
      399821 400815 401806 404797 410780 411770 414762 417754
      419747
 0.50 423025 419006 416997 412990 407990 403988 399982 393975
      387970 379968 373965 370966 368970 365978 368987 371994
      376003 380008 388013 395016 402020 409023 415027 420027
      423025 423025
 0.50 344897 344890 342887 331889 327896 325907 322915 323921
      325926 328934 330938 333939 335934 337930 337925 337919
      337915 338910 342902 344897
 0.50 292092 291088 286088 281085 270077 267072 264066 261060
      257056 253052 249051 245051 240055 242062 246074 249080
      253084 262086 266089 270094 274098 278099 281098 286095
      291094 292092
 1.00 408759 406738 406734 404730 401732 400735 398741 394747
      385755 382760 383764 385767 388767 390767 392771 387785
      381796 380803 378810 371819 364830 362836 361843 363850
      367851 372847 377848 384838 390827 393821 396814 397807
      399800 403788 405780 407773 408759
 1.00 410014 410007 407003 400995 394987 391983 387981 378976
      373974 371974 371976 372982 375987 377992 380995 387004
      390007 394010 402014 410014
 1.00 262074 262072 260069 258067 256065 254063 252061 250060
      248060 249062 250065 251068 252071 253073 256075 259076
      260076 262074
 1.50 405755 404745 403736 401736 400739 397744 395749 393757
      393762 395766 396774 399776 400774 403768 405762 405755
 1.50 398793 399788 397784 392788 386799 382811 379816 375819
      367828 364834 364836 364840 365843 367845 370844 372842
      380836 385831 387827 389819 390813 395801 398793
 1.50 399002 398000 397998 394996 392994 391992 389990 387990
      387995 388997 390000 391002 392005 395006 398005 399002
 2.00 404755 403750 403746 402743 399744 398747 397749 396754
      396756 396761 397765 398768 399767 401765 403762 403757
      404755
 2.00 387811 386808 385808 385809 385811 386812 387811
 2.00 386824 386820 384817 382818 380821 379823 378827 376825
      372825 371826 370831 371834 373831 374829 376826 378829
      381828 384827 386824

$$





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