Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 280831
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
430 AM EDT SUN SEP 28 2014


PRELIM DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION
VALID SEP 28/1200 UTC THRU OCT 01/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR

DAY 1...

...INTERMOUNTAIN WEST...

THE SEASONABLY STRONG AND RATHER SLOW MOVING MID/UPPER LEVEL TROF
OVER THE WESTERN STATES WILL PRODUCE ANOTHER DAY OF ORGANIZED
RAINS THRUOUT MUCH OF THE INTERMOUNTAIN WEST..BUT WITH AMOUNTS ON
THE DECREASE COMPARED TO THE PAST DAY OR SO IN A LOWER PW/LESS
MOIST AIRMASS.  LOW/LOWERING HEIGHTS/COOL AIR ALOFT ALONG WITH
SOME CONTINUED FAVORABLE UPPER LEVEL DIVERGENCE/UPPER DIFFLUENCE
WILL LEAD TO THE RATHER WIDESPREAD RAINFALL EVENT FROM PORTIONS OF
THE CENTRAL/SOUTHERN GREAT BASIN INTO THE ROCKIES..WITH H5 S/WV
ENERGY WRAPPING AROUND THE EVER SO SLOWLY PROGRESSIVE H5 LOW
BRINGING RAINS BACK THRU THE NORTHERN GREAT BASIN AND INTO WESTERN
PARTS OF THE CENTRAL GREAT BASIN.  RAINFALL AMOUNTS OF 0.50-1.00
INCH MOST LIKELY..GENERALLY IN LINE WITH MODEL QPF
SOLUTIONS..ALTHOUGH SOME ISOLATED HEAVIER TOTALS CERTAINLY
POSSIBLE.


...GULF COAST/SOUTHEASTERN STATES...

WHEREAS THERE WAS DECENT MODEL QPF AGREEMENT OUT WEST..SUCH IS NOT
NECESSARILY THE CASE THRU THE GULF COAST AND SOUTHEASTERN
STATES..LEADING TO A LOWER THAN AVERAGE CONFIDENCE FORECAST.  THE
MODELS HAVE BEEN HAVING TROUBLE THRU THIS REGION FOR THE PAST DAY
OR SO..WITH 00Z GUIDANCE FROM LAST NIGHT TOO QUICK TO BRING SOME
HEAVIER RAINS INLAND..AND THIS IS THE CASE AGAIN TONIGHT WITH AT
LEAST A FEW OF THE GLOBAL MODEL QPFS..LIKELY CAUSED IN PART BY
FEEDBACK ISSUES.  GIVEN THAT THE FLOW PATTERN IS FORECAST TO
REMAIN QUITE FLAT ALOFT THIS PERIOD THRU THIS AREA..AND WITH ONLY
A VERY WEAK AREA OF LOW PRESSURE MOVING ALONG THE SURFACE BOUNDARY
THAT WILL PROBABLY REMAIN IN THE NORTHERN GULF OF MEXICO..HAVE
KEPT THE MORE SIGNIFICANT RAINS CONFINED TO NEAR THE CENTRAL AND
EASTERN GULF COAST STATES..AT LEAST INTO MONDAY MORNING.  GAVE
VIRTUALLY NO CREDENCE TO THE 00Z GFS..OLD 12Z ECMWF HIRES AND TO A
LESSER EXTENT THE 00Z UKMET HIRES QPFS..ALL OF WHICH APPEARED TO
HAVE FEEDBACK PROBLEMS..AND INSTEAD WENT CLOSER TO THE HIRES ARW
AND NMMB..CANADIAN GEM REGIONAL AND EVEN THE NAM QPFS FOR THIS
FORECAST.  DO SEE THE POTENTIAL FOR SOME 1-2+ INCH AREAL AVERAGE
RAINS ALONG THE IMMEDIATE CENTRAL/EASTERN GULF COAST..WITH
ISOLATED HEAVIER AMOUNTS POSSIBLE.  HAVE JUST SEEN THE 00Z ECMWF
HIRES QPF..AND IT IS NOW MUCH MORE SUPPRESSED THAN ITS 12Z
RUNS..WHICH DOES ADD A BIT OF CONFIDENCE THAT WE ARE AT LEAST
GOING IN THE CORRECT DIRECTION.

DAYS 2 AND 3

PACIFIC NORTHWEST INTO THE NORTHERN ROCKIES...

GENERALLY LIGHT PRECIPITATION WILL ACCOMPANY THE DEPARTURE OF THE
CLOSED LOW OVER THE NORTHERN ROCKIES SUNDAY NIGHT INTO MONDAY AND
AGAIN FROM MONDAY ONWARD AS THE NEXT SHORTWAVE TROUGH QUICKLY
ARRIVES INTO THE PACIFIC NORTHWEST.  MODEL AGREEMENT IS QUITE GOOD
WITH ONLY MINIMAL SPREAD WITH A BLEND OFF THE NAM/GFS/ECMWF USED
TO DERIVE THE FINAL QPF.

PLAINS...

A NARROW SWATH OF MODERATE TO LOCALLY HEAVY PRECIPITATION WILL
ACCOMPANY THE DEEPENING PHASE OF THE LEE ROCKIES CYCLONE ACROSS
THE CENTRAL AND NORTHERN HIGH PLAINS MONDAY INTO TUESDAY.  THE
NEGATIVE TILT TO THE ACCOMPANYING UPPER TROUGH AND INCREASING
MOISTURE/INSTABILITY SUPPORT A CHANCE THAT THE STRONGER GFS/ECMWF
SOLUTIONS MAY BE CORRECT AND IF SO WOULD SUPPORT A SLIGHT INCREASE
IN THE QPF.  AT THE MOMENT HOWEVER...BALANCING THESE SOLUTIONS
WITH THE EQUALLY PLAUSIBLE WEAKER SOLUTIONS IS PREFERRED UNTIL
MODEL CLUSTERING IMPROVES.  THE RESULT IS A NARROW AXIS OF 1 TO 2
INCH BASIN-AVERAGE TOTALS ALONG THE MONTANA/NORTH DAKOTA BORDER.
ANOTHER AXIS OF QPF IS EXPECTED TO FORM ALONG THE SOUTHWARD
TRAILING COLD FRONT INTO THE SOUTHERN PLAINS...WITH A BLEND OF THE
GFS/ECMWF PREFERRED IN THIS AREA.

GREAT LAKES/NORTHEAST...

RECENT GUIDANCE HAS TRENDED TOWARD THE SLOWER AND MORE AMPLIFIED
ECMWF SOLUTION THE LAST DAY OR SO AND THUS HAVE NUDGED THE QPF IN
ITS DIRECTION...RESULTING IN SMALL POCKETS OF LIGHT TO
OCCASIONALLY MODERATE PRECIPITATION WITHIN THE TROUGH`S PASSAGE
MONDAY INTO TUESDAY.

SOUTHEAST...

THE 00Z MODEL CONSENSUS HAS ADJUSTED TO A FLATTER AND OVERALL
WEAKER SOLUTION INLAND ACROSS THE SOUTHEAST...WITH FEWER OR LESS
EGREGIOUS EXAMPLES OF CONVECTIVE GRID-SCALE FEEDBACK...ALTHOUGH
SOME STILL EXISTS...WARRANTING SOME CAUTION IN USING SOME OF THE
MODEL QPF WITHOUT SOME ADJUSTMENTS.  OVERALL..THE FINAL WPC QPF
FOR DAYS 2 AND 3 REFLECT A MIDWAY FORECAST BETWEEN THE ENSEMBLE
MEAN PROBABILITIES WHICH HAVE BEEN STEADIEST AND MOST RELIABLE THE
LAST COUPLE OF DAYS...WITH A 3 WAY DETERMINISTIC BLEND INVOLVING
THE 00Z GFS AND LAST 2 RUNS OF THE ECMWF.  THE RISK FOR EXCEEDING
FFG GUIDANCE REMAINS IN THE SLIGHT CATEGORY FROM THE FLORIDA
PANHANDLE TOWARD THE SOUTHEAST COAST...BUT HAS DIMINISHED
INLAND...WITH THE CENTROID CURRENTLY ACROSS SOUTH CENTRAL OR
SOUTHEAST GEORGIA.  CONFIDENCE IN THE EXACT DETAILS OF THIS RAIN
EVENT INCLUDING LOCATION AND AMOUNTS REMAINS UNUSUALLY LOW BUT IS
CONSISTENT WITH THE CONTINUING MODEL SPREAD INCLUDING FROM THE
ENSEMBLE MEMBERS.

TERRY/JAMES

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

24HR QP VT 29/12Z
 0.01 522263 517258 510255 505252 499252 493252 486249 480249
      475255 466264 456269 452274 450279 451282 454285 456286
      462287 476289 488289 501292 513291
 0.01 519874 519858 518849 517844 515832 512822 509813 507807
      505804 504798 501788 498777 488751 480738 473734 468742
      467762 464815 459837 458844 458852 459864 462887 463901
      463913 462941 462966 465974 466973 469972 470975 472993
      472004 469012 467022 467036 465043 464046 462045 459035
      456026 455020 453017 449014 446010 447994 447982 447976
      445971 441972 438975 435977 431978 429980 428983 427988
      427011 426016 424021 421024 416024 411032 405038 403040
      401044 398048 395050 388053 383054 378054 372050 363049
      355048 347048 332049 328051 328056 331058 335057 342060
      342067 327078 323083 315088 313098 309100 306103 307111
      315114 331116 336121 343125 346125 349122 350115 350110
      349105 352104 356103 358105 361107 366108 370108 371115
      372120 371125 367131 365135 366137 372138 375135 388128
      394127 401127 409128 415132 418140 419145 418150 417156
      415160 413165 410167 405167 403163 399154 392149 388149
      383148 380150 377153 374157 374165 373170 371174 363177
      362184 366190 370195 375201 385205 393211 400213 407212
      415213 422209 432198 442179 447175 451173 454171 457165
      458157 462150 465142 480139 486137 488134 488129 486124
      484118 482107 483093 486080 489069 492057 496036 500018
      504997 508976 511949 512938 513924 514920 514912 515897
      516890 518884 518878 519874
 0.01 365820 365810 362805 357803 351804 346806 339807 335806
      333803 330796 329794 328788 328780 326773 322771 318771
      317773 314779 310791 304803 300806 295808 288809 282807
      276806 270803 263801 256802 248808 249814 253819 258823
      260825 261829 265843 266849 267857 266871 266880 265888
      262903 262909 260915 257945 257963 259966 261968 264968
      271969 277967 283964 287960 292955 295950 300941 305931
      308926 314920 317915 322911 324907 326900 326885 326876
      328868 334857 340849 348841 357832 365820
 0.01 287081 285074 282070 277065 271062 260055 255052 248050
      236045 236050 239056 247065 256073 268080 273083 279086
      284085 287081
 0.25 515277 516272 514269 512267 508266 505268 499270 493268
      488267 485267 482270 483274 487275 492275 497275 503278
      508280 513279 515277
 0.25 508877 509869 507864 505857 504844 504837 502831 500820
      497811 492805 489803 485806 481815 480822 476842 474864
      474875 477885 479889 479896 478905 477911 478917 481927
      484937 485947 484974 484988 485997 485010 485014 486020
      487022 489020 490016 493008 495997 496985 497971 497959
      499937 502925 503916 506893 506884 508877
 0.25 469093 469085 468081 464073 459067 457063 454056 453051
      451047 446041 439037 434037 431040 420040 414044 411047
      410052 408057 405060 397064 390067 386068 382067 378066
      373063 367062 364066 362074 361079 361084 364088 367091
      377095 385097 401106 405115 407118 412118 422121 425124
      428129 429140 427150 426157 425163 423168 422172 425172
      430173 434171 440168 446163 449159 450153 455144 457140
      457135 457122 456117 457111 463099 469093
 0.25 392183 394179 393175 391173 388172 385173 383175 381178
      380181 380185 382187 386187 387187 390185 392183
 0.25 336826 335821 332818 327818 320821 312818 306819 302819
      294819 279814 264810 260809 256809 254812 257816 268823
      276827 280834 282838 282843 282853 282862 281873 279893
      278914 279926 280934 284941 288942 291939 301928 306920
      309913 313907 317900 316881 322865 326857 328848 332836
      336826
 0.25 322797 322795 322793 321792 319793 318793 318796 317796
      317798 317800 317802 318804 320803 320802 321799 322797
 0.50 499863 498852 497840 496834 494832 490825 487831 485841
      484851 484858 485862 488865 489871 491881 491884 495882
      497873 499865 499863
 0.50 449143 449132 449122 447113 444103 443096 445090 448084
      450080 450075 455075 449061 448055 446050 439045 431044
      424045 420046 417047 415051 413057 414062 414066 407070
      400071 398075 394076 388076 383075 377072 371068 369070
      368077 368082 370086 374088 378089 386086 394089 401090
      409093 413099 414112 417115 422116 428119 431127 434138
      434143 433149 432157 433162 436163 440162 443159 445155
      446149 449143
 0.50 324848 326838 325833 322828 312825 297828 289830 288835
      288841 287854 286866 285881 285893 284908 284920 285926
      288930 293928 297925 303918 308908 313898 311891 309887
      311877 316869 320859 324848
 1.00 442132 443130 443127 442126 442125 441123 439123 437123
      437124 437126 437129 438131 438132 440133 441133 442132
 1.00 432102 433099 432097 432094 431093 431092 430090 428089
      426091 424093 424095 424096 425098 427101 429103 430103
      432102 432102
 1.00 305888 306878 309870 314862 317851 318840 317836 315835
      309835 301837 297840 294853 291866 290881 290889 291895
      293899 296899 302897 306892 305888
 1.00 297912 298910 297908 296908 295907 294906 293904 292906
      292908 292910 292912 292914 293915 295914 297912 297912
 1.50 301884 302878 304868 308864 313856 314847 313843 309840
      303842 301848 297859 297866 296875 296885 299886 301884

24HR QP VT 30/12Z
 0.01 503246 506237 506228 505221 503218 500215 499213 496212
      491209 483207 478208 458215 447215 441216 439217 437221
      438228 437231 434232 427224 422226 420231 418233 414233
      413237 415239 425239 428237 430238 432244 439246 440249
      443250 452245 464246 470247 477249 482252 486256 488259
      491258 497255 501251 503246
 0.01 494166 492160 488158 477152 471150 466149 464150 463146
      460140 455136 451133 444132 438133 434135 429137 427138
      423136 419132 417132 415136 413142 411150 409157 405163
      405166 406174 410178 417180 421180 426177 431173 434169
      437168 440170 446173 447175 448180 451183 453184 454181
      458175 462171 473170 480171 487173 490173 492171 494166
 0.01 501057 499050 500045 502042 502035 499031 493025 486021
      471019 457017 453014 452011 452005 452994 450988 445980
      438976 432975 424974 410974 393976 380980 370988 367992
      367001 372006 374008 373010 370012 364015 359019 350028
      342036 338041 336049 335054 329049 323048 317050 317057
      322061 325063 324065 320071 319075 320080 324087 326092
      329094 333095 342091 351081 356075 359073 364072 368078
      370085 373089 378093 383095 391094 397091 400088 400083
      402080 406080 413078 422073 449064 455063 460067 468073
      471072 474067 475063 479063 485061 491061 501057
 0.01 499801 498782 496768 494759 491751 486737 481723 479719
      478711 477701 478693 476674 475665 474661 472659 461663
      448667 445668 444671 441678 441706 453730 457736 458746
      455757 453765 450772 446783 437804 431815 425827 421831
      418836 416845 418850 420853 422856 424856 429854 429859
      426873 426880 429883 432885 434885 439880 441879 442883
      444889 447892 450891 451889 456881 461869 462864 465861
      472861 481855 484852 487847 491841 494834 497822 498811
      498804 499801
 0.01 449114 450108 450102 447094 438093 436095 434101 423110
      418111 414109 411108 407108 400110 392114 389114 385115
      384120 386125 387127 391128 396129 400127 405125 413122
      418121 421124 424132 428125 432124 437124 443121 448114
      449114
 0.01 431152 429150 428150 426151 427152 429153 431152
 0.01 368757 368748 366739 363736 358734 354735 349740 342752
      330770 323780 320786 315790 298803 293807 287804 281800
      278801 276803 275805 271804 267802 256805 257810 261813
      266818 272821 272823 271826 268831 266841 265848 264856
      264864 264874 265890 268893 269895 273895 279893 284890
      287888 289890 289897 289906 290912 293925 294929 296928
      303924 304918 305911 306896 307890 309884 316873 320869
      324865 335859 341851 343845 346839 355830 360826 362820
      364816 366809 366802 365798 363795 364786 365782 365778
      364772 365769 368757
 0.01 276972 277968 277964 276961 272961 268961 266962 263963
      262966 260968 260972 261974 264976 266977 268978 270978
      274977 275974 276972
 0.25 489218 489215 485213 482213 479213 477213 474214 472216
      473219 476220 478220 481220 485220 486220 489218
 0.25 489805 488793 487788 486785 484784 480784 479782 477775
      477767 477757 473756 471752 467759 465762 463767 459788
      459792 460796 464788 466787 466792 466804 465814 465819
      465824 470831 472834 476836 480835 482832 486823 488815
      489805
 0.25 486047 487042 485039 481035 476031 469029 444023 438021
      433019 423008 422007 418006 413008 405008 399009 387013
      382016 380018 379022 382026 387027 395028 402030 407033
      410038 411044 408050 406054 408058 413057 418052 423050
      431051 437052 445052 451055 456057 462058 468058 475056
      481053 486047
 0.25 453154 454149 453147 451144 449143 446142 444143 442146
      440149 440154 442156 444158 447159 450158 452156 453154
 0.25 451811 452809 451806 450806 450807 448808 448809 447811
      447812 446814 447816 449814 450812 451811
 0.25 426990 422987 419986 414985 408984 403986 401989 402993
      406994 410993 415993 420993 424992 426990
 0.25 375075 374074 373073 373072 372073 372075 372076 374076
      375075
 0.25 364041 363038 360038 358039 356040 354042 352044 351046
      349050 352052 354050 356049 359047 362045 364043 364041
 0.25 354779 355775 354769 350764 344766 339771 333781 329786
      324791 314798 309803 305808 298817 296820 295824 298831
      299834 298837 295841 292844 287845 285846 283850 285859
      288864 295876 296880 299882 303878 306871 309865 312859
      315856 331851 336847 338842 341836 346830 348823 349817
      350809 348805 349801 352791 354779
 0.50 473049 475042 472039 465034 459031 450029 442028 433024
      426021 420016 417014 413014 404015 398018 400022 404024
      412026 416034 420041 427044 445048 453051 456053 461053
      468052 473049
 0.50 347785 346782 342782 337788 325795 318799 313805 310810
      308814 308818 306826 307837 307843 309846 314847 321847
      324849 327848 333844 336837 336827 337817 343803 346797
      347787 347785
 0.50 302855 303853 302850 300850 299851 298851 297853 297855
      298857 298858 300857 302855 302855
 1.00 443041 443036 442035 438034 436033 433032 430032 428034
      428035 429038 432040 434041 438041 441041 443041
 1.00 337806 331804 326810 321814 316819 316828 315835 317838
      321840 324838 326834 329827 330819 333813 337806
 1.00 326803 325802 323802 322804 321806 322808 324807 325805
      325804 326803

24HR QP VT 01/12Z
 0.01 531047 531041 526038 522035 515033 510033 505031 493029
      489027 482025 473020 462017 452022 443025 438027 435027
      433025 429026 428030 433042 436046 441050 451055 461059
      473061 485063 489062 496063 508064 517060 520055 525053
      529051 531047
 0.01 511160 510154 507151 499146 481136 476135 473133 469130
      464127 457120 458112 457106 453098 446091 441091 438093
      434096 429094 427096 426103 423105 417106 399111 396112
      395117 401125 408133 411136 414134 415131 416132 416139
      417144 417149 416156 417161 421162 422155 426146 427139
      428135 429132 430130 433128 436129 441137 441165 444174
      447178 449180 452181 459178 461175 464170 467166 471169
      476177 484183 487185 492184 494181 497176 503166 508164
      511160
 0.01 518009 517004 515001 512998 507996 498994 490995 485997
      482999 477006 476011 478015 484021 488023 493024 503024
      510022 513019 516015 518009
 0.01 496223 496220 494217 493214 489212 477212 465215 459220
      456218 453220 447219 440219 437221 438224 441226 444225
      450223 456222 457225 461226 467225 472223 478222 482222
      486224 489225 492225 496223
 0.01 489247 489240 484238 481236 477235 472235 467234 464235
      463240 466242 469242 474244 479245 484247 489247
 0.01 504942 502938 499936 491929 484923 479921 474921 469921
      465920 453919 441920 433925 424928 416933 398940 389944
      381949 364960 359966 353974 348982 344986 345991 346996
      351996 360994 366992 368991 369994 372998 376999 380999
      385997 394993 409982 412980 417979 424979 429980 440982
      448986 457989 463989 464988 464984 464976 461971 458968
      464967 467965 469960 473962 479962 497967 504942
 0.01 460238 461235 460234 459234 458234 457235 455235 453234
      452234 451235 450235 449236 448239 449240 451240 453239
      454240 456240 458239 460238 460238
 0.01 448778 448769 445762 439750 438742 435736 430734 424732
      416737 407745 399770 391778 387782 383788 382792 383801
      391808 397808 400807 402810 399816 398823 399831 400835
      401837 403839 407839 411835 416825 424815 440798 445788
      448778
 0.01 450078 449077 448075 446075 445072 443070 444072 445072
      446075 448077 448078 449078 450078
 0.01 413078 413073 413071 412068 410070 406070 405070 401071
      399071 396073 397076 399078 402079 406080 409080 411080
      413078
 0.01 406806 405805 403805 401806 403808 405807 406806
 0.01 400756 399747 395744 391743 386747 381752 378755 377762
      377766 379768 384771 387771 392769 397763 399758 400756
 0.01 350758 349747 345740 340735 329737 322741 316745 310749
      307752 304757 300762 297770 293776 290784 287791 285800
      270798 262796 257796 254798 251801 249805 249808 251812
      255818 261822 266827 269829 271835 273842 277850 280857
      284859 289858 293853 296845 303829 306823 310816 322804
      333795 338788 342781 345776 347769 349764 350758
 0.01 317926 314913 312909 308905 300897 296893 291890 289891
      288895 287902 288910 290914 291918 292922 292927 292935
      290937 290941 292945 297948 304947 308945 312941 314935
      317926
 0.25 509045 508042 505040 499037 486034 478033 471032 463031
      455031 445037 443038 443043 448048 453051 460053 475055
      482056 490056 501053 507050 509045
 0.25 446118 447116 448114 448111 447109 446107 444106 442105
      440105 439107 438107 438110 438111 439112 440115 441117
      441118 443120 444120 444121 445121 446119 446118
 0.25 454937 454935 451934 446936 435940 426945 416949 407954
      402956 400957 397956 392956 387956 381958 376961 368967
      364971 361976 359980 358983 359985 369982 379979 391976
      402977 412974 423971 428969 431965 435963 439959 443955
      445947 454937
 0.25 335769 332765 329764 325766 322769 318774 316779 313785
      311788 311792 313795 317794 321791 325787 329783 332778
      334771 335769
 0.25 282817 282813 279811 276810 274809 271808 269808 265807
      264809 264811 266812 269814 272816 273817 275818 279819
      282817
 0.50 498046 495042 490041 482038 477037 472037 462036 457036
      453038 451041 451044 453046 461050 470051 479052 488051
      495049 498046
 0.50 423966 421962 418959 415959 410961 407962 403966 401968
      403971 409971 413970 417969 421967 423966
 0.50 387968 386963 384962 380962 379963 376965 373967 371969
      370971 368973 367976 370978 372976 375975 377974 380972
      382972 385970 387968
 1.00 468046 467044 465043 463043 462044 460044 459045 460045
      462046 463046 465046 467046 468046

$$




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