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Quantitative Precipitation Forecast (QPF) Discussion
 
(Latest Discussion - Issued 1855Z Aug 23, 2014)
 
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Abbreviations and acronyms used in this product
 
Geographic Boundaries -  Map 1: Color  Black/White       Map 2: Color  Black/White


QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
254 PM EDT SAT AUG 23 2014


PRELIM DAY 1 QPF DISCUSSION
VALID AUG 24/0000 UTC THRU AUG 25/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1...

...EASTERN FOOTHILLS OF THE NORTHERN ROCKIES INTO THE NORTHERN
PLAINS AND UPPER MISSISSIPPI VALLEY...

THE EARLY STAGES OF A SIGNIFICANT RAINFALL EVENT IS CURRENTLY
TAKING SHAPE ACROSS THE EASTERN FOOTHILLS OF THE NORTHERN ROCKIES
EASTWARD INTO THE NORTHERN PLAINS. THE EVOLVING DIFFLUENT UPPER
LEVEL FLOW AND STRENGTHENING POCKET OF UPPER LEVEL DIVERGENCE
AHEAD OF THE VORT MAX CURRENTLY LIFTING N/NNE ACROSS WRN NE AND
SWRN SD IS GENERATING A SEPARATE WIDESPREAD AREA OF GENERALLY
MODERATE RAINFALL ACROSS WRN SD AND WRN ND. DRY AIR ALOFT
(STEEPENING THETA-E LAPSE RATES) NORTH OF THE AFOREMENTIONED VORT
MAX WILL LIKELY ENHANCE CONVECTION AHEAD OF THIS VORT MAX AS IT
LIFTS N/NNE THIS AFTERNOON. MEANWHILE...THE MORE EXPANSIVE AREA OF
MOD-HVY RAINFALL CONTINUES OVER MUCH OF MT...WITHIN THE LAYER OF
BROAD UPPER LEVEL DIFFLUENCE...GOOD UPPER DIVERGENCE...AND
ANOMALOUS LOW-MID LAYER MOISTURE/THETA-E POOLING FROM THE E/SE VIA
THE WESTERN EXPANSION OF THE TROWAL ZONE. OVER TIME...THE
THERMODYNAMIC PROFILES OVER EASTERN AREAS OF THE OUTLOOK AREA
(EASTERN DAKOTAS INTO MN) WILL BECOME INCREASINGLY FAVORABLE FOR
MORE OF A CONVECTIVE CONTRIBUTION AND THUS AN ENHANCED EXCESSIVE
RAINFALL THREAT...ALONG THE N/NW PERIPHERY OF THE INSTABILITY AXIS
(MUCAPES CLIMBING BTWN 1000-2000 J/KG PER THE ARW WITH PWATS
RISING TO AROUND 1.75 INCHES. PWATS THROUGHOUT THE OUTLOOK AREA
ARE OR SHORTLY WILL BE AROUND 3 STD DEVIATIONS ABOVE NORMAL...OR
AOA THE 99TH PERCENTILE FOR THE AREA THIS TIME OF YEAR.
MEANWHILE...THE NEGATIVE U-WIND COMPONENT OR EASTERLY FLOW
ANOMALIES AT 850-700 ARE AT 5+ STANDARD DEVIATIONS PER THE GEFS
AND ECENS.

AS A RESULT OF THE ANOMALOUS COMBINATION OF FAVORABLE COOL-SEASON
DYNAMICAL FORCING ALONG WITH THE FAVORABLE THERMODYNAMIC (DEEP
MOIST) PROFILES...THE MODEL GUIDANCE...BOTH GLOBAL AND HIGH
RES...CONTINUE TO SHOW A STRONG SIGNAL FOR A SIGNIFICANT RAINFALL
EVENT ACROSS THE EASTERN FOOTHILLS OF THE NRN ROCKIES INTO THE NRN
PLAINS AND AT LEAST WRN PTNS OF THE UPPER MS VLY...WITH THE LATEST
SSEO MEAN PROBABILITIES OF EXCEEDING 3 AND 6 HOURLY FFG OVER 70
PERCENT IN THE HIGH RISK AREA ACROSS PORTIONS OF CENTRAL MT ALONG
THE WESTERN PERIPHERY OF THE TROWAL ZONE. 24 HOUR AREAL-AVERAGE
QPF WITHIN THE HIGH RISK AREA PER THE GLOBAL MODEL CONSENSUS
RANGES FROM 2.5 TO 5 INCHES...WHICH IS SUPPORTED BY THE SREF AND
GEFS PROBABILITIES OF 50% OR GREATER OF RECEIVING MORE THAN 3
INCHES IN 24 HOURS. AT THE SAME TIME...VIRTUALLY ALL OF THE HIGHER
RES GUIDANCE SHOW LOCALLY HIGHER AMOUNTS OF 6+ INCHES. FARTHER
EAST INTO THE DAKOTAS AND WRN MN...THE TOTAL RAINFALL IS EXPECTED
TO AVERAGE CLOSER TO 1-3 INCHES...HOWEVER GIVEN THE GREATER
INSTABILITY TO FEED OFF OF (ESPECIALLY IN THE EASTERN DAKOTAS AND
WRN MN)...THERE WILL MORE DEVIATION FROM THE MEAN WITH LOCALLY
HEAVIER...POTENTIALLY EXCESSIVE AREAS OF RAINFALL...SUPPORTED BY
THE ISOLATED 4-6+ INCH BANDS PER THE LATEST 4KM NAM CONEST...NSSL
WRF...AND WRF-ARW.


...OH VALLEY/CENTRAL APPALACHIANS INTO PORTIONS OF THE MID
ATLANTIC STATES...

THE DEEPENING WESTERN ATLANTIC H5 TROF ALONG WITH THE BUILDING H5
RIDGE FROM JUST WEST OF THE APPALACHIANS BACK INTO THE MID/LOWER
MS VALLEY WILL LEAD TO A MORE NORTHERLY MID/UPPER LEVEL FLOW
REGIME OVER THE EASTERN STATES...WHICH WILL HELP TO PUSH A COLD
FRONT SOUTHWARD THRU THE OH VALLEY AND MID ATLANTIC STATES DURING
THE PERIOD. AN AXIS OF ABOVE AVERAGE PW VALUES WILL PERSIST IN THE
VICINITY OF THIS BOUNDARY..SUPPORTING A CONTINUED SHOWERY PATTERN
WITH IT. NOT A LOT OF CONFIDENCE WITH QPF DETAILS IN THIS
PATTERN...WITH MODEL QPFS NOT IN ESPECIALLY GOOD AGREEMENT...SO
KEPT AREAL AVERAGE RAINFALL AMOUNTS GENERALLY ON THE LIGHT-MOD
SIDE.

HURLEY

GRAPHICS AVAILABLE ON THE WEB AT www.wpc.ncep.noaa.gov/qpf/qpf2.shtml

24HR QP VT 25/00Z
 0.01 556947 557916 556907 555901 554892 553886 551871 550865
      549859 540842 533827 531824 528825 525826 522828 516845
      512853 507861 497874 484877 461903 450916 448923 444929
      440937 438940 433942 428945 423952 418958 417961 419964
      424961 425964 424966 422971 419975 408989 403996 399002
      394008 393018 396024 393034 391042 383044 376048 365047
      360053 357055 354056 354058 356058 361057 365056 369054
      378051 380053 381056 381061 375067 373070 373077 375084
      378086 382086 384085 388085 393085 396084 403080 407074
      415070 416066 413061 411058 407056 404057 402055 399049
      398047 399045 408043 416039 419037 425038 433041 438033
      446021 454018 456029 453035 448041 438052 433059 429068
      425078 425084 426089 428101 426105 426110 426119 428123
      430121 435117 439116 443117 445119 444123 443128 441132
      435136 434139 432138 429137 433152 437160 442167 444173
      445178 444186 444192 446196 449195 453195 456193 460185
      464184 466182 458167 457163 460159 464160 467164 472168
      475167 479167 481167 483170 484174 484181 481185 478187
      470185 466189 467194 468200 465204 460210 461214 464218
      482219 485219 488221 496226 498227 500232 502239 506248
      507251 511249 514249 516243 515234 510226 505220 500210
      499203 500200 503200 506200 510198 513194 515188 516180
      522176 525174 527171 526162 523155 516150 512149 510146
      504139 500131 498128 500124 510108 515099 520091 526082
      531074 539059 542049 544037 548013 552993 555969 555955
      556947
 0.01 450896 450894 447893 443892 440891 438889 437880 435873
      433869 426862 410858 406856 400856 396855 393849 391847
      387849 384848 383844 383840 386838 389834 392831 394826
      398823 402820 404818 407813 407807 405803 400803 396802
      392798 398790 400785 401778 396766 391759 376754 372758
      372762 375769 378774 377780 374784 367785 362783 359779
      355776 353772 352766 354762 357754 356747 355741 352738
      347738 343737 339739 335743 331747 327748 327741 330732
      332728 331722 329716 328713 326713 320714 317717 312723
      307732 305736 305745 302768 300778 296786 294791 291793
      288797 285799 275802 270804 265808 258805 254803 253808
      251813 248816 248821 250824 265831 273834 279843 285852
      289856 293857 302860 309866 312875 319879 323881 323888
      324894 328895 327898 329902 332901 339893 346893 352893
      355891 364888 370889 374890 386908 390910 394913 397917
      402918 425917 429916 433914 435911 440910 448906 450896
 0.01 415101 415097 413094 406093 403097 400098 395102 389107
      385111 373118 373123 376125 384128 389128 392131 389139
      388141 390144 398145 401144 404142 404135 400132 398129
      397125 399122 403115 407107 411103 415101
 0.01 394977 395970 395963 395956 391954 388954 386956 384961
      385965 385969 384972 383977 384981 387984 391984 393979
      394977
 0.01 357069 341071 337069 336065 338061 338055 335051 331048
      325047 322044 308038 307045 304050 298057 295060 292062
      284064 278064 274062 266057 259053 250049 242045 232042
      228051 227055 227060 227066 228072 231081 235088 241094
      246101 251108 257114 260123 262125 267126 276122 283119
      289114 295106 300107 303107 310103 313100 313094 318093
      317089 321085 327086 330088 335089 342085 347081 351077
      354073 357069
 0.01 360009 358007 354009 351011 349013 347017 345022 347024
      348026 352024 354020 356016 358011 360009
 0.01 295910 295908 294906 293904 293903 291901 289901 289902
      288903 287904 287906 287908 287910 287912 288914 290916
      292916 293914 294914 295912 295910
 0.25 544949 544937 544922 542899 541889 539882 536875 533870
      529864 526862 522861 517863 515865 512871 508877 503882
      493889 483898 477901 473901 469902 465907 462913 459920
      458927 450940 442952 438957 435962 432970 430978 430983
      433985 440989 448990 454993 459997 463003 469014 469019
      468025 465033 462041 458047 449056 444061 442065 437071
      435074 435081 439086 444091 450104 455116 459121 466125
      474128 481127 486123 489117 493111 496105 505094 513082
      520071 526057 531039 535019 539001 542982 543963 544949
 0.25 483209 483208 481207 480206 478206 476207 474207 473208
      472208 472211 474212 475212 476212 477212 479211 480211
      481211 483210 483209
 0.25 450153 449151 448149 447148 447147 445145 444144 442144
      441146 442148 442149 443151 444152 445152 446154 448154
      450153 450153
 0.25 429890 428883 424877 419874 412873 404873 398872 394868
      391865 387864 383865 380866 378865 376859 376855 374851
      370848 367844 364840 362837 359837 356831 351826 347827
      344829 343832 341838 336840 333837 331828 328823 328814
      331809 336799 339798 342798 347800 353797 357792 360785
      354784 349785 344785 342783 340780 340773 342768 345762
      345757 342756 338756 335758 315768 313773 311781 311788
      312795 314800 315808 310818 311822 314829 318834 322838
      325844 327848 329852 328856 330862 339869 343875 348875
      360878 367877 370876 372878 376883 382885 387888 390889
      394889 401889 406891 411892 416891 422891 426893 429890
 0.25 388788 385783 381784 374792 367799 360806 355815 352820
      353826 354827 357826 360823 366814 373808 378805 381800
      386792 388788
 0.25 303085 301081 298079 291076 282072 275069 258065 250061
      244058 239057 239061 242067 247072 251079 251085 253088
      256094 261100 268105 276107 283104 291092 299088 303085
 0.25 300825 299819 295815 290812 284811 277812 272816 272821
      276824 281825 286829 291832 297830 300825
 0.50 539968 540944 540932 540920 538901 537892 535884 532877
      528872 517878 512881 508885 501894 498899 492904 484914
      476921 467927 464933 459939 450948 442956 439961 436966
      434974 434980 436983 442985 448986 456988 460991 467999
      470004 473012 473023 472031 469039 467045 460055 452065
      450074 449082 453095 457108 460114 466118 469120 473120
      479118 487109 493101 502090 510079 516069 519063 521057
      526039 530021 537989 538976 539968
 0.50 471915 471912 471910 471907 470906 469907 469909 468910
      468912 467915 468917 469918 470917 470916 471915
 0.50 410884 409882 407883 407885 408885 409885 410884
 0.50 374801 374800 372801 370801 370802 372802 374801 374801
 0.50 367869 366860 360854 358848 352846 349849 346849 339845
      335847 336852 340856 344858 346860 351866 355870 359872
      363872 367869
 0.50 357788 357786 356785 355786 354786 353787 351788 350789
      349789 348791 348792 347794 348796 350796 352796 353795
      354795 355793 355792 356790 357789 357788
 0.50 338766 336765 331769 326772 323776 322784 322788 324795
      328792 330785 333780 335774 337769 338766
 0.50 293085 291082 289079 281076 277075 272075 275079 268078
      264078 264082 264087 266090 271094 274096 278096 282093
      288088 293085
 0.50 290820 289818 288817 286816 284815 282815 281815 279815
      278815 277816 275817 275818 275820 276820 277821 278821
      279822 281822 283822 285822 287822 288821 290820
 1.00 533939 533930 533921 531905 529897 527892 526889 524887
      519888 508909 503916 500920 495922 485925 480927 476931
      473935 471940 471945 473949 477953 478956 477960 471969
      472972 474974 478976 481979 483984 480989 478996 478011
      478020 478027 475040 464060 459069 457075 457084 462095
      465100 468104 472106 475104 482099 490093 498085 503078
      509069 514058 518044 520031 522015 525001 528985 530970
      530964 531955 533939
 1.00 459959 457957 454957 450959 447962 443966 442969 439973
      440979 443977 447975 450973 454970 457966 458962 459959
 1.50 527939 527931 526922 524910 521907 518908 513914 507922
      503931 501934 497936 492935 487936 484938 483941 484946
      484954 483961 482967 484970 491974 494977 496981 497987
      497995 495004 494996 492993 488995 486001 483013 480037
      475047 470055 466063 463072 461079 463086 468094 473095
      477094 484090 491086 497079 501071 506063 510054 511047
      512041 512014 515001 518989 523968 527939
 2.00 520949 521934 520925 518921 512923 508931 505942 501952
      501960 503965 507975 511977 514975 517970 518965 520952
      520949
 2.00 509993 508991 507988 505985 502983 500986 500990 499995
      499000 499006 500009 501012 504011 505008 506003 507001
      508996 509993
 2.00 505042 504032 501026 499025 496027 492032 490042 485045
      480047 476051 472058 469064 466072 465080 467087 471091
      474091 477089 481087 486083 491078 495072 498067 503052
      505042
 2.00 497957 496954 496952 496950 496949 494947 492949 492952
      492954 492957 494957 496958 497957
 2.00 494962 492962 491963 490965 491965 492965 493965 494962
      494962
 3.00 486068 487060 485059 483060 478059 475061 473066 472071
      471078 471084 475084 478079 480075 483072 486069 486068