Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 160701
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
300 AM EDT SUN JUL 16 2017


PRELIM DAY 1 QPF DISCUSSION
VALID JUL 16/1200 UTC THRU JUL 17/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


...SOUTHERN / SOUTHEASTERN U.S...

SOUTHEAST GEORGIA AND THE COASTAL CAROLINAS SIT IN A FAVORABLE
POSITION FOR ENHANCED COVERAGE OF AFTERNOON CONVECTION PRODUCING
HEAVY RAIN. EASTERN U.S. TROUGHING WILL UNDERGO SLIGHT
AMPLIFICATION TODAY WITH THE MEAN TROUGH AXIS BACK ACROSS WESTERN
GEORGIA AND ALABAMA. THIS PLACES THE SOUTHERN ATLANTIC COAST
BENEATH SLIGHTLY DIFLUENT UPPER FLOW WHICH WILL AIDE THUNDERSTORM
GROWTH...INTENSITY...AND LONGEVITY...AS STORMS INITATE NEAR THE
COASTAL CONVERGENCE ZONE / SEA BREEZE AND ALSO WITHIN THE MOIST
AND STRONGLY HEATED ENVIRONMENT FARTHER INLAND TOWARD A SLOWLY
SAGGING FRONTAL BOUNDARY. IN THE ABSENCE OF A WELL DEFINED UPPER
SHORTWAVE...AND WITH MODEST DEEP LAYER WIND SPEEDS AND SHEAR...IT
WILL BE DIFFICULT TO ANTICIPATE EXACTLY WHERE CONVECTION WILL
BECOME MORE ORGANIZED. THE MODELS...HOWEVER...ARE IN FAIRLY GOOD
AGREEMENT...THE ONLY EXCEPTION BEING THE GFS WHICH SEEMS TO HAVE
SYSTEMATIC PROBLEMS UNDER CERTAIN REGIMES BY PLACING QPF OFFSHORE
WHEN THE OVERWHELMING MAJORITY OF THE MODEL GUIDANCE PLACES IT
JUST ONSHORE. THE GLOBAL MODEL CONSENSUS OVERLAPS NICELY WITH THE
HI-RES MODELS...AND WPC PREFERRED THE NSSL WRF...NCEP
WRF-NMMB...AND CANADIAN GEM REGIONAL FOR THE DETAILS. THE RESULT
WAS A SPATIAL LAYOUT SIMILAR TO THE PREVIOUS FORECAST...AND A
SLIGHT INCREASE TO AREAL AVERAGE AMOUNTS...EXPECTING A WET DAY
ACROSS SOUTHERN GA TOWARD SVANNAH AND CHARLESTON...AND CONTINUING
UP THE COAST INTO THE OUTER BANKS. WITH PRECIPITABLE WATER AROUND
2 INCHES...THERE WILL BE VERY HEAVY RAIN RATES IN THE STRONGEST
CELLS...WITH POTENTIAL FOR ISOLATED 4-PLUS INCH AMOUNTS WHEREVER
CELL MERGERS OR TRAINING OCCURS.

BACK WEST...WPC WAS FAIRLY GENEROUS WITH THE AREAL COVERAGE OF
HYDROLOGICALLY SIGNIFICANT PRECIPITATION AT LEAST A QUARTER INCH
OR MORE WITHIN A ZONE OF FAVORABLE MID LEVEL MOISTURE...WHICH WILL
ENHANCE RAINFALL EFFICIENCY FROM SOUTHERN ALABAMA TOWARD THE UPPER
TEXAS COAST. HI-RES MODELS ARE INDICATIVE OF VERY HEAVY RAIN
ASSOCIATED WITH A MID LEVEL CIRCULATION NEAR COASTAL
TEXAS...ALTHOUGH THE HEAVIEST MAY TEND TO OCCUR JUST OFFSHORE.


...SOUTHWEST U.S. AND CENTRAL/SOUTHERN HIGH PLAINS...

THE PAST FEW DAYS HAVE BEEN ACTIVE FROM THE MOGOLLON RIM
SOUTHWARD...AND AS MOISTURE DEPTH CONTINUES TO CREEP WEST THROUGH
THE DESERTS WE SAW AN ENVIRONMENT ON SATURDAY THAT SUPPORTED
CONVECTION SURVIVING DOWN INTO THE VALLEYS AND DESERT AREAS OF
SOUTHERN ARIZONA. SUNDAY SHOULD BE SIMILAR AS STEERING FLOW
REMAINS NORTHEAST TO SOUTHWEST...WITH THE RIDGE POSITION OVER THE
NV/UT BORDER. THE MODELS TEND NOT TO DO A GREAT JOB OF FOLLOWING
THE CONVECTION DOWN INTO THE LOWER TERRAIN...SO WE USED A BIT OF
EXTRAPOLATION AND THE NAM CAPE FIELD TO PUSH QPF AS FAR WEST AS WE
COULD DO REASONABLY...ALTHOUGH EFFICIENCY AND AREAL AVERAGE
AMOUNTS WILL DROP OFF WITH WESTWARD AND SOUTHWARD EXTENT. THE
FLASH FLOOD RISK APPEARS LIKE THAT OF A TYPICAL MONSOON DAY...AND
NOT PARTICULARLY ENHANCED BY ANY IDENTIFIABLE SMALL SCALE FEATURES.

MEANWHILE THE SMALL VORTICITY MAXIMUM OVER COLORADO...EMBEDDED IN
MEAN RIDGING...HAD BECOME MORE PRODUCTIVE WITH LARGER SCALE
CONVECTION ON SATURDAY. STILL...ITS RADIUS OF INFLUENCE IS FAIRLY
SMALL...WITH WEAK WIND FIELDS SURROUNDING IT. THE FEATURE WILL
OPEN UP A BIT AND BECOME STRETCHED NORTH TO SOUTH WHILE ALSO
BEGINNING TO LIFT NORTHWARD LATE SUNDAY...UNDER THE ENCOURAGEMENT
OF NORTHERN STREAM FLOW PICKING UP ACROSS THE ROCKIES. THIS SETS
UP AN AXIS OF MODERATE AND LOCALLY HEAVY RAINFALL ALONG THE KS/CO
BORDER AND EXTENDING BACK INTO NORTHERN NEW MEXICO. IN A SOMEWHAT
UNRELATED FASHION...A SOUTHWARD EXTENSION OF DEEP LAYER MOISTURE
WAS DRIFTING ONTO THE HIGH PLAINS WITHIN EASTERLY FLOW...AND WILL
SUPPORT SCATTERED DOWNPOURS DOWN THROUGH WESTERN OKLAHOMA AND WEST
TEXAS. WPC QPF FAVORED A MIX OF CONTINUITY / 00Z WRF-NMM...AND OUR
IN-HOUSE ENSEMBLE.


...NORTHERN TIER...

WAVES TOPPING THE WESTERN U.S. RIDGE WILL SUPPORT PRECIPITATION IN
THE NORTHERN ROCKEIS/PLAINS AND...SEPARATELY...DOWNSTREAM INTO THE
OHIO VALLEY AND NORTHEAST. THE ENVIRONMENT FAVORS PROGRESSIVE
THUNDERSTORMS WHICH WILL HOLD AREAL AVERAGE AMOUNTS DOWN BELOW
THREE QUARTERS INCH IN MOST CASES...THOUGH THE TYPICAL HEAVIER
RAIN WILL OCCUR IN SPOTS. SIMILAR TO THE REST OF THE NATION...WPC
CONTINUITY LOOKED GOOD HERE...AND WE TRENDED TOWARD THE WRF-NMM
AND OUR LATEST IN-HOUSE ENSEMBLE GUIDANCE.

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

BURKE

24HR QP VT 17/12Z
 0.01 537210 538204 537198 534187 533182 531177 528173 525171
      521169 518172 515175 512176 508179 507185 509189 513190
      518193 521197 524206 525211 528215 531217 535215 537210
 0.01 523036 524026 522020 519015 518011 518005 515000 518994
      519984 517975 511966 513948 515942 517934 515928 514926
      510925 505926 501930 496931 491936 484942 479947 475952
      472957 470964 468970 466978 466997 461011 457024 453030
      449033 446037 440040 439047 442051 447054 450060 449063
      446064 440065 434076 430081 426086 420095 418102 417106
      419108 426108 430107 437109 440115 441122 445128 449129
      454126 461118 468106 472103 475099 476090 474084 476077
      478071 479063 480052 481047 483047 483055 496057 502057
      506056 511053 516049 523036
 0.01 499229 499228 498226 498224 498223 497221 496220 495220
      494220 494223 495225 495228 495229 497230 498230 499229
 0.01 494684 492672 488665 485658 482655 478655 475654 473656
      469658 467662 460676 459681 456685 452691 449699 446707
      441713 441717 440722 437726 432727 428728 427731 434730
      438730 438734 436737 431737 428738 425740 422743 422746
      424750 423756 421759 417761 413762 410765 407772 406781
      406786 408789 410793 410800 404815 400822 396830 389843
      381857 375874 373881 371885 371891 374900 376903 378905
      385909 387911 389917 392925 394933 398941 403947 408951
      410954 412954 411945 410933 411924 410918 409914 409901
      409894 409889 413889 415886 419879 424862 430847 434840
      440832 443825 446819 450811 454804 461790 464782 466772
      467760 468751 472743 473734 472730 473726 476720 478716
      482713 488708 491703 492696 494684
 0.01 479239 480236 479235 478234 476232 475235 476236 477238
      478239 479239
 0.01 490038 489036 487036 486037 484040 483042 482045 483047
      485045 487043 487042 488040 489040 490038
 0.01 413106 414099 412094 409093 405095 403098 399101 391105
      388107 384110 378116 371119 367116 366112 367108 367101
      368098 370097 377099 387097 392092 397082 403075 410068
      412064 412059 409056 404053 398049 400044 404042 408042
      411037 415026 415019 415014 414008 415003 412993 409991
      405989 396988 387993 384993 381991 342982 342987 344991
      348997 346001 343002 338001 333999 332994 331988 330984
      327980 320982 314989 311989 310987 310981 310977 312973
      319967 324962 327958 332954 336952 341954 346954 349950
      352947 352941 343926 343912 342905 343898 349878 352868
      355859 357855 356847 360839 364830 365825 368822 373815
      377812 380808 383802 387799 391798 395794 396791 395786
      391787 388789 382795 380798 378796 379790 377786 375785
      375782 380775 380770 379762 375752 373730 368719 365716
      360716 359711 354711 350711 348715 344722 341726 340731
      335749 325764 321771 317779 312788 309792 309798 307802
      303804 295808 286811 281811 277808 279799 276790 271789
      267790 261791 256790 250791 245792 240797 239806 242818
      245827 254830 262832 269838 272842 278843 281843 281846
      281851 280861 283872 284879 286884 285894 283903 281912
      280923 279928 277931 272937 267946 264954 262965 268979
      262980 259983 253987 250991 248996 246002 249006 253009
      257007 261009 264012 267019 271021 274021 277017 276013
      271006 272004 276005 278009 279017 280021 283026 286027
      289025 291024 292027 292031 292034 297036 347022 351021
      356021 365023 365029 363032 360036 356038 352041 350046
      347048 342049 338051 332051 325054 340062 346068 347071
      345073 341073 331073 326070 324065 321061 316060 312062
      306062 301060 298058 290054
 0.01 290054 287055 284057 280058 274057 266055 261055 257058
      254060 251064 250068 252072 258077 260081 262084 269090
      276095 292104 294120 298127 302135 311149 308151 305154
      307158 311161 314164 319166 326166 337169 340171 345171
      344167 340164 333159 330160 324160 317155 329156 344147
      357139 364136 371130 383118 399114 405114 408112 413106
 0.01 402741 401734 397734 394738 391741 389744 387749 385754
      387756 389754 392752 396749 399746 402741 402741
 0.25 493015 491012 486012 482002 481997 479993 476997 473001
      470011 467021 465025 463030 464037 467039 470036 472032
      475029 479027 484029 488026 490023 493018 493015
 0.25 490959 488957 486957 484958 482961 481964 480967 478969
      476972 476977 479979 482977 484974 485972 486969 487967
      489962 490959
 0.25 460758 459751 457746 452746 446746 443746 438749 435758
      433770 431775 430781 428792 425803 421812 415821 412830
      411837 413843 416842 420838 428832 429828 430824 429820
      431816 435813 446797 451788 456779 459769 460758
 0.25 460099 462092 462084 463077 463070 462065 460062 457064
      455069 455073 454080 455086 455093 455098 456101 458101
      460099
 0.25 455110 455108 454106 453106 451107 449109 449110 448111
      447114 446116 446117 448119 450118 451117 452116 452115
      453112 454112 455110
 0.25 407866 407860 406856 404852 401851 396857 391863 387869
      386877 387886 388890 392892 397885 402882 406875 407866
 0.25 406026 407020 406016 402008 397004 390004 383002 381001
      378003 375004 371004 363003 359002 358004 359009 362011
      367011 373010 376015 373023 370030 366039 368043 371040
      376035 380031 387032 394035 401032 404029 406026
 0.25 376082 377073 378069 377066 373061 368059 363059 358062
      356069 358073 359078 361079 365080 367078 371073 372075
      372080 373084 376082
 0.25 368757 367747 367736 364728 361725 358724 355723 353724
      348730 342744 336757 329769 325775 322782 316796 310808
      308811 305813 299816 296818 294821 294824 296826 302831
      302838 303845 303853 302859 297853 294849 291850 290854
      293863 293874 294881 296887 299888 302898 291904 289904
      288908 286916 285926 285931 283934 279938 276945 272951
      270958 269963 270966 277970 280971 283971 288966 296955
      301951 308950 312944 316937 320931 321923 321915 319911
      315910 315903 316898 318895 324891 327892 330891 333886
      336878 338871 342865 345858 346850 349831 350823 350818
      351814 353808 354803 354799 357790 360784 365770 368757
 0.25 357127 356119 352115 350107 348101 341089 338087 335089
      333090 332094 331099 328099 324094 320089 315084 313079
      311076 307075 295069 289067 281066 272066 265064 260064
      258067 259069 263074 266079 277087 287094 293097 297102
      300116 304121 308126 312132 316135 324138 330136 342132
      346129 350129 355129 357127
 0.25 363049 362047 360045 358047 358048 357049 356049 356051
      356053 358052 359051 360051 361050 363049
 0.25 354088 355086 354085 352086 351088 351089 353089 354088
 0.25 321001 321999 321997 320996 320997 319997 317999 316001
      315002 314003 313005 312007 311008 310009 311009 313010
      314009 315009 316008 318007 318006 319005 320003 321001
 0.25 303886 302884 301884 300886 302888 303886
 0.25 292832 291826 287824 281824 276823 272820 269816 263808
      259805 255803 251801 248801 248804 250809 253813 261818
      267825 276829 285833 292832
 0.25 291993 292991 291990 290990 288990 287991 286993 288994
      290994 291993 291993
 0.25 278993 278989 277986 273986 271987 268988 266988 263990
      262993 262995 266996 268997 269997 273996 276995 278993
 0.25 270800 270799 268798 266799 265800 265801 264802 265803
      267803 268802 270800 270800
 0.50 454769 454763 453757 450755 447755 443760 438767 435775
      435785 434794 436798 439795 444790 448784 452777 454769
 0.50 403023 402019 401012 399009 394009 390010 386011 384016
      384022 386025 389027 395029 400028 402025 403023
 0.50 399871 399869 398867 396868 395869 395870 394872 393874
      393876 393878 393879 395880 396878 397878 398876 398874
      398873 399871
 0.50 372066 371064 370062 368061 366061 364062 363063 362064
      361065 360066 360067 360068 362069 364070 366069 367069
      369069 371068 372066
 0.50 365758 363748 363737 361731 358729 355728 352731 348737
      344745 346754 344757 341759 335766 331773 326780 322788
      316804 313811 310816 306817 302819 299821 300824 303827
      308834 311843 310853 309863 307874 309879 312881 317880
      319876 322877 324878 327877 328873 329867 326863 322863
      322859 324855 331851 334843 334837 332833 332827 334823
      338816 344798 353784 360769 363763 365758
 0.50 344118 345114 345109 344103 342098 338092 335097 332103
      329107 328111 329116 329122 333127 339125 343120 344118
 0.50 321128 321106 317090 310085 307079 299075 291073 283072
      275070 265070 269075 271078 274081 281085 287089 294094
      300099 302107 304110 305115 309121 314127 319129 321128
 0.50 318924 317918 312918 308921 307926 306930 305936 302939
      301943 305945 308942 310939 312934 314930 317926 318924
 0.50 292933 292931 292930 290930 290931 290933 290935 290937
      291935 292933 292933
 0.50 292927 292926 291924 290924 289924 290926 291927 292927
      292927
 0.50 288954 289947 290944 288941 286941 283944 280947 277951
      276955 274960 274963 277966 281967 284964 287961 288956
      288954
 0.50 288939 290937 288937 288939 288940 288939
 0.50 271993 270992 268992 267992 268993 270993 271993
 0.50 264815 263813 262812 261811 260809 259809 258808 257807
      256807 254806 253808 254810 256812 257812 258813 259813
      260815 262816 264815
 1.00 396020 395019 393019 391019 391020 391021 393022 395022
      396020
 1.00 358745 358743 358741 357739 357737 356736 355737 354737
      353739 353741 353742 353744 353746 354747 355748 356749
      356748 357746 358745
 1.00 354768 353766 351766 348768 343768 340771 336778 331783
      325789 322797 317813 313820 311824 311827 314836 315841
      318844 321843 323838 325829 333815 334806 338799 346785
      348776 353770 354768
 1.00 335115 335112 334112 334114 334116 335115
 1.50 334793 333789 331789 328792 325799 324804 323812 321817
      319819 321821 325820 329816 329807 331801 333796 334793
 1.50 319830 318828 316827 316828 315830 317831 318831 319830

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