Quantitative Precipitation Forecast
Issued by NWS

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865
FXUS04 KWBC 240610
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
209 AM EDT SUN SEP 24 2017


PRELIM DAY 1 QPF DISCUSSION
VALID SEP 24/1200 UTC THRU SEP 25/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

...GREAT PLAINS / CENTRAL U.S...

A FULL LATITUDE CORRIDOR OF MODERATE RAINFALL WILL CONTINUE SUNDAY
FROM TEXAS TO MINNESOTA. THIS WAS DRIVEN BY A VERY DEEP TROUGH IN
THE WEST AND EQUALLY STOUT DOWNSTREAM RIDGE OVER THE GREAT LAKES.
RAINFALL INTENSITY WAS TEMPERED...HOWEVER...BY MARGINAL LAPSE
RATES IN THE WARM SECTOR AND THE BULK OF DEEP LAYER ASCENT
REMAINING BACK INTO THE COLD SECTOR. ON SUNDAY A JET STREAK AND
ASSOCIATED MINOR SURFACE WAVE WILL TOP THE RIDGE...DRAGGING DEEP
LAYER ASCENT UP THROUGH NORTHERN MINNESOTA. THIS WILL TAKE THE
DEEP FORCING AWAY FROM THE SOMEWHAT MORE UNSTABLE ATMOSPHERE DOWN
OVER THE CENTRAL AND SOUTHERN PLAINS STATES...BUT SUFFICIENT
FRONTOGENESIS AND CONVERGENCE OF THE LOW LEVEL FLOW...ESPECIALLY
JUST TO THE COOL SIDE OF THE FRONT...SHOULD ALLOW FOR CONTINUED
RAIN/THUNDERSTORM DEVELOPMENT FROM WESTERN KANSAS THROUGH EASTERN
SOUTH DAKOTA. ADDITIONAL CLUSTERS OF THUNDERSTORMS / SMALL MCS
ACTIVITY WILL LIKELY OCCUR DOWN THROUGH WEST TEXAS AND EASTERN NEW
MEXICO...BLEEDING OVER INTO WESTERN OKLAHOMA WITH TIME. AT THESE
MORE SOUTHERLY LATITUDES OUTFLOW BOUNDARIES WILL PLAY A BIGGER
ROLE IN DETERMINING THE PLACEMENT OF HEAVIER PRECIPITATION...SO WE
HAVE LESS CONFIDENCE IN THE DETAILS. STILL...THE MODEL GUIDANCE
SHOWS PRETTY STRONG AGREEMENT THROUGHOUT THE CENTRAL U.S. WITH
THIS LARGE SCALE WEATHER SYSTEM...ALLOWING WPC TO MAINTAIN
CONTINUITY. FOR SOME OF THE DETAILS WE WERE SLIGHTLY IN FAVOR OF
THE NAM CONUS NEST AND WRF-NMMB...ALONG WITH OUR IN-HOUSE
BIAS-CORRECTED ENSEMBLE. OUR EDITS RESULTED IN VERY LITTLE CHANGE
TO THE PREVIOUS FORECAST.

ONE SIGNAL OF NOTE IS THE INCREASE OF QPF OVER THE BIG BEND AREA
IN TEXAS. THE WRF-ARW WAS PARTICULARLY AGGRESSIVE THERE...AND
OTHER GUIDANCE TRENDED UPWARDS AS WELL. THE WPC TREND WAS MORE
CONSERVATIVE...GIVEN THE POTENTIAL FOR OUTFLOW AND PROPAGATION TO
SUPPRESS ANY EXTREME VALUES...BUT THERE IS POTENTIAL FOR LOCAL
INTENSE RAIN RATES...AS THE UPPER PATTERN OPENS UP AND IS MORE
DIFLUENT ACROSS THIS AREA...WHILE ALSO TAPPING INTO MOISTURE
ASSOCIATED WITH TROPICAL STORM PILAR.


...ROCKIES / NORTHERN UTAH...

THE DIFLUENT NORTHERN SIDE OF THE CLOSED UPPER LOW CIRCULATING
THROUGH UTAH...WAS SUPPORTING ORGANIZED RAIN AND SNOW EARLY SUNDAY
MORNING. THE LOW WILL TRACK UP THROUGH WYOMING TODAY. THE WPC QPF
BLEND HERE WAS SIMILAR TO THE REST OF THE NATION...WITH 50/30/20
PERCENTAGES ON CONTINUITY/00Z IN-HOUSE ENSEMBLE/00Z NAM CONUS
NEST. SOME UPSLOPE ENHANCEMENT WILL FAVOR NORTHEAST FACING
SLOPES...ESPECIALLY ACROSS SOUTHERN WYOMING...ALTHOUGH WITH THE
PRESENCE OF THE UPPER LOW THE VALLEYS WILL GET IN ON SOME OF THE
PRECIPITATION AS WELL. A FEW SPOTTY LIQUID EQUIVALENT AMOUNTS
APPROACHING THREE QUARTERS INCH ARE EXPECTED...WHILE MOST OF THE
REGION WILL SEE A TENTH TO A HALF INCH LIQUID.


...ELSEWHERE...

SOME COLUMN DRYING IS EXPECTED TO SUPPRESS PRECIPITATION TODAY
OVER EASTERN AND NORTHERN FLORIDA...WHILE A RETROGRADING UPPER LOW
SUPPORTS SHOWERS ALONG THE CENTRAL GULF COAST. VERY LIGHT AREAL
AVERAGE RAIN IS FORECAST ALONG THE TEXAS GULF COAST...OVER
NORTHERN ARKANSAS...ASSOCIATED WITH DIURNAL HEATING IN NORTHERN
MAINE...AND APPROACHING WESTERN WASHINGTON BY LATE TONIGHT.

BURKE

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

24HR QP VT 25/12Z
 0.01 535212 536201 534193 531189 529187 526188 521189 516193
      515195 515200 520204 523210 525215 528217 531216 535212
 0.01 535883 535872 534865 531849 530839 528828 525814 517803
      513798 506800 502801 500803 499814 498824 495827 491841
      488853 485868 484887 480894 473900 464908 456916 451920
      447923 437929 428935 408946 402949 395954 386960 376968
      366974 324992 309995 303997 295997 280001 271006 269008
      265008 260005 255004 251005 249006 248010 247012 248014
      252018 257021 259034 254040 253046 253055 251061 255064
      257066 262067 267069 273069 282064 293067 298066 303068
      307070 311070 316067 322064 326064 329063 332062 334058
      337056 340055 352052 358050 361046 368046 371046 374048
      383056 392057 400069 407081 405085 403087 397090 388100
      382110 379121 378126 379128 383133 389135 396137 404138
      412139 416140 418138 424135 429130 433124 440115 453096
      459084 462069 462064 461060 463057 466053 474043 491025
      495020 499016 505009 510004 513999 515992 518986 521978
      524971 529955 531948 532943 532936 533926 534923 534917
      535899 535888 535883
 0.01 504281 506269 507259 506253 507245 506240 505232 504228
      501225 499227 490231 471230 468230 464233 461237 460245
      460250 461255 463269 461283 460290 460298 461308 462314
      465318 475323 481325 485326 488323 491319 496307 497300
      499295 504281 504281
 0.01 491667 491661 489657 485648 482645 479645 475652 474662
      474667 471667 466661 462659 461664 452671 456680 458694
      460706 463709 466710 468702 468698 470697 475697 479704
      481708 483707 484702 484697 488688 490680 491667 491667
 0.01 429032 426030 424028 421028 418028 414027 412029 409029
      407033 409035 410038 413039 417040 420039 422038 424036
      426034 429032
 0.01 376907 376898 374893 367885 363879 361872 359870 355874
      352888 353896 351903 350909 351912 351916 353922 353925
      357925 362929 366934 369932 371930 372927 373925 373921
      373911 376907
 0.01 254730 255736 257741 262751 268757 274768 276770 278776
      283788 285791 289793 294795 299792 308789 308796 310797
      325782 331776 335771 338767 343759 345753 345750 343748
      339751 337748 337746 337738 334727 329716 324706 318698
      315696
 0.01 328900 328888 326884 324880 317873 310868 305862 301854
      295845 290837 288835 283835 278835 281832 284828 283822
      281818 277815 275813 274809 277809 278806 276801 273797
      270794 266792 258791 253791 250793 246796 244800 240809
      237817 237826 239831 241836 243838 245837 247833 248831
      251831 253834 259839 266847 271855 267862 269873 271877
      274881 276894 276905 277911 278915 285922 290931 296933
      299931 301927 307919 314913 317910 322907 326904 328900
 0.01 307822 307820 305818 303820 301821 301823 302825 303825
      305825 307823 307822
 0.01 301992 301987 299984 296977 296967 296961 294959 293955
      295953 298950 298945 292945 288947 287951 284957 279964
      277965 273965 263965 257964 254966 253970 253978 257980
      259979 267979 273983 282983 287984 289987 293991 299994
      301992
 0.25 528907 528893 528879 526867 524855 521848 518845 515846
      511851 503867 496883 492893 487899 481908 474914 460925
      450934 443940 436944 419952 412957 405963 394971 387977
      382981 370984 362987 346994 317007 305008 295009 289009
      285010 281012 278016 278022 280025 281027 279030 271034
      266038 263048 263054 266057 275054 287054 355037 363035
      369032 377030 386029 397025 404021 411017 420014 449003
      471002 479999 487995 492990 498986 503980 509973 515963
      519954 526934 527920 528907
 0.25 493282 494277 496273 496267 494264 491266 489268 487271
      486274 484279 484281 484284 485288 488288 490286 492284
      493282
 0.25 450075 447067 444054 435055 431053 425053 423057 425063
      420072 421083 419088 421091 423096 420099 415098 410095
      406095 403099 401104 396115 395118 399120 409121 417123
      423122 427120 432114 436100 438076 441074 444075 448078
      450075
 0.25 409059 409058 407058 405058 405059 407059 409059 409059
 0.25 266724 268736 273749 280759 283762 288765 293767 300768
      306767 312764 320756 323751 326745 327739 327733 326726
      323719 317708 310700
 0.25 308890 308882 306876 301864 294855 290852 285852 281856
      279862 278868 279877 283889 284904 284909 287914 291913
      295908 302900 305896 308890
 0.25 261813 261811 260809 258807 256806 254807 253808 253810
      255811 256812 258813 260814 261813
 0.50 525918 526904 525891 525877 522865 520860 516861 513864
      510869 501884 498892 494899 486914 476932 471940 466946
      464947 463941 466934 466930 463931 460932 454937 447943
      440947 423954 417957 412961 400971 393979 387986 380989
      371990 342000 325008 311017 304019 298023 286032 273043
      280047 289048 297047 302044 308040 311040 313038 314034
      317030 321029 331029 341027 349024 358024 364027 371026
      377023 396018 411011 424006 438998 445994 453988 461986
      466985 470986 476987 484985 490982 497977 503970 509962
      517946 522934 524924 525918
 0.50 429111 430108 428104 426103 422105 419107 414106 411103
      408101 406103 407107 410110 412113 413118 418118 422118
      426115 428113 429111
 0.50 429084 429082 430080 429077 427076 426077 426079 426082
      427083 428084 428085 429084
 0.50 269721 269728 271735 275745 280755 288761 292763 297763
      303763 308761 316754 322745 324736 324729 321722 316712
      310704 305701
 0.50 304888 304883 303878 300872 297864 293859 290857 286858
      283865 282873 284881 287887 291895 293897 297898 299897
      302893 304888
 0.50 293016 293014 291012 289012 287013 285013 285014 284016
      284018 285019 287020 289020 291018 292017 293016
 1.00 520921 521909 520901 519897 515890 512888 509887 506892
      502899 494913 491920 491922 495922 498924 500928 501933
      501939 496955 495960 495965 498964 501961 509947 515932
      518926 520921
 1.00 444966 444961 443958 438957 423960 417961 412966 407970
      401977 400984 396989 390993 383995 376997 371999 363002
      356003 349004 343006 336010 332014 338017 345018 349018
      352016 358013 364010 366013 367015 366020 368021 374018
      384013 399009 411005 419002 424999 431990 434983 438978
      442973 444966
 1.00 273720 272725 273733 278745 283752 287756 291758 295759
      302758 311753 314750 318746 320741 321735 320726 317720
      315715 308707 302703
 1.00 307034 306031 305030 301028 297029 295030 294031 291033
      289035 289039 291040 295041 298040 300039 303038 306036
      307034
 1.00 294872 294870 294868 293867 293866 292864 291863 290864
      289866 289868 290870 290871 291872 292874 294874 294872
 1.50 423968 423966 421968 416973 412977 407982 401993 396997
      389000 376001 373003 371006 372011 376012 381008 388006
      393004 397002 401003 408003 412001 416998 413996 413991
      417987 421981 423968
 1.50 277718 275726 275732 277738 281746 287753 290755 295756
      302755 310751 316744 318737 318731 317724 313716 306710
      300706
 1.50 304034 303032 301031 299031 297033 296033 295034 295035
      295036 297037 299037 301037 302036 302035 304034
 2.00 279717 276728 278738 280743 284748 287750 291753 296754
      302753 310749 313745 316740 317729 316725 313719 307712
      299707 297706
 3.00 283714 280723 278732 279738 282742 287747 290750 294751
      299751 305749 311744 314736 315727 314723 311719 305714
      297709 292709
 4.00 313732 313726 311721 306716 302713 298711 294711 288713
      285715 283718 281727 280738 286744 292749 297749 303748
      309743 312739 313734 313732
 5.00 312734 312728 310722 305716 298713 293713 287715 285718
      283723 282731 281737 285741 291746 295748 299747 306744
      309741 312736 312734
 6.00 311728 310724 308721 303717 296714 291715 287717 285720
      283729 282735 286741 291745 294746 299746 306743 310737
      311728 311728
 7.00 310732 310727 308723 304718 296716 289717 285722 284731
      284734 285738 290742 292744 297745 304742 309737 310732
 8.00 310728 307722 304719 298717 291718 288719 287722 286728
      284735 289740 293743 298744 304741 308737 309730 310728
 9.00 308731 309727 307722 303719 297719 290720 288722 287726
      286733 286737 291741 297743 303740 307736 308731
10.00 308729 307724 304721 301719 295720 290721 288724 287730
      287734 289738 293741 296742 301740 305738 306734 307729
      308729

$$





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