Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 171831
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
230 PM EDT WED SEP 17 2014


PRELIM DAY 1 QPF DISCUSSION
VALID SEP 18/0000 UTC THRU SEP 19/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1
~~~~~

COASTAL PACIFIC NORTHWEST INTO NORTHWEST CALIFORNIA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
THE NORTHEAST PACIFIC UPPER-LEVEL TROUGH WILL BE PUSHING EASTWARD
TOWARD THE PACIFIC NORTHWEST/NORTHERN CA REGION.   THE ASSOCIATED
LOW-LEVEL FLOW WILL REMAIN PARALLEL TO THE COAST, KEEPING
PRECIPITATION FROM MOVING VERY FAR INLAND AND CONFINED TO COASTAL
SECTIONS FROM NORTHERN CA INTO THE COASTAL PACIFIC NORTHWEST.
OUTSIDE OF THE 12Z GFS AND PARALLEL GFS RUNS, WHICH DISPLAY
CONVECTIVE FEEDBACK OFFSHORE THE OR/CA BORDER, THE GUIDANCE WAS IN
GOOD AGREEMENT WITH THE 12Z WPC QPF, SO MAINTAINED GOOD CONTINUITY.


SOUTHWEST INTO THE SOUTHERN PLAINS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
WIDESPREAD HEAVY TO EXCESSIVE RAINFALL IS LIKELY THIS PERIOD,
ASSOCIATED WITH THE CIRCULATION OF ODILE AND POSSIBLY A SMALL
VORTICITY MAXIMUM ON ITS EASTERN SIDE WHICH APPEARS TO BE LINKED
TO THE REMAINS OF TROPICAL DEPRESSION 16-E.  A MUCH ABOVE AVERAGE
PRECIPITABLE WATER (PW) AXIS WILL STRETCH FROM SOUTHERN
CA/SOUTHERN NV---EASTWARD INTO AZ---NM AND THROUGH TX.  OBSERVED
PW VALUES ACROSS THESE AREAS ARE NEAR THE 99TH PERCENTILE (NEAR
RECORD VALUES) FOR MID-SEPTEMBER AND THE ANOMALOUS MOISTURE SHOULD
REMAIN IN PLACE INTO THURSDAY.  INSTABILITY SHOULD BE LESS OF AN
ISSUE TODAY AS AREAS OF NORTHERNMOST MEXICO, WESTERN TX, AND
SOUTHEAST NM HAVE BEEN SUBJECT TO DAYTIME HEATING, WHICH HAS
INCREASED MIXED LAYER CAPE VALUES TO ROUGHLY 1000 J/KG PER THE
MOST RECENT SPC MESOANALYSIS.

CONSIDERING THE AVAILABLE MOISTURE, HOURLY RAIN RATES UP TO 3" ARE
POSSIBLE ANYWHERE WITH THIS REGION.  THE HOUSTON/GALVESTON TX
FORECAST OFFICE (HGX) REPORTED RAINFALL OF 1.28" IN 30 MINUTES
WITHIN THE INITIAL THUNDERSTORMS THAT FORMED LATE THIS MORNING.
THERE IS A STRONG MODEL SIGNAL FOR HEAVY TO EXCESSIVE RAINFALL
AMOUNTS ACROSS SOUTHEASTERN AZ AND SOUTHERN NM, LEADING TO HIGH
CONFIDENCE ACROSS THESE AREAS.  THE MOST RECENT MESOSCALE GUIDANCE
INDICATES LOCAL AMOUNTS OF 5-8" IN THIS REGION FROM THIS AFTERNOON
INTO THURSDAY.

MODEL SPREAD CONTINUES CONCERNING EXACTLY WHERE HEAVY RAIN
DEVELOPS ACROSS TEXAS.  THE MESOSCALE MODELS ARE QUITE EMPHATIC
ACROSS THIS AREA, WITH LOCAL MAXIMA OF 6-12" NOTED WITHIN THEIR
OUTPUT.  WITH THE ABOVE MENTIONED HIGH PW AXIS AND MODEL FORECASTS
OF UPPER DIFFLUENCE MAXIMUM UNDER AN UPPER-LEVEL HIGH IN THIS HIGH
PW AXIS---FAVOR THE IDEA OF SPREADING HEAVY TO LOCALLY EXCESSIVE
RAINFALL AMOUNTS EASTWARD QUICKER.  WHILE MODELS DO NOT DEPICT
MUCH PRECIPITATION ON THE NORTHWESTERN PORTION OF THE ANOMALOUS PW
AXIS FROM SOUTHERN CA INTO SOUTHERN NV AND NW AZ, SCATTERED
CONVECTION IS LIKELY AGAIN ACROSS THESE AREAS WITH LOCALLY HEAVY
TO EXCESSIVE RAINFALL AMOUNTS POSSIBLE.  THE 12Z WPC QPF
CONTINUITY ACROSS EASTERN NM AND NORTHWEST TX WAS SHIFTED
NORTHWARD PER THE 12Z GUIDANCE AND RECENT RADAR TRENDS AND ADDED
MORE TO THE QPF NEAR LA`S VEGAS AND NORTHWEST AZ TO ACCOUNT FOR
EXPECTATIONS ACROSS THE DESERT SOUTHWEST.


PORTIONS OF MO/AR/KS
~~~~~~~~~~~~~~~~~~~~
THE WESTERN EXTENT OF THE SURFACE FRONTAL BOUNDARY SHOULD REMAIN
STATIONARY TODAY, WHICH SHOULD CONTINUE TO POOL PWS OF 1.50-1.75"
PER RECENT RAP RUNS.  SHORTWAVE ENERGY IN THE NORTHWEST FLOW ALOFT
MAY SPAWN A COUPLE ROUNDS OF CONVECTION NEAR AND TO THE NORTHEAST
OF THIS BOUNDARY.  CONFIDENCE IS NOT HIGH WITH THE AXIS OF MAXIMUM
AMOUNTS---BUT THERE IS A GENERAL MODEL CONSENSUS FOR MAXIMUM
AMOUNTS NEAR THE KS/OK/MO BORDER JUNCTION.  WIDESPREAD MODERATE TO
HEAVY RAINS ARE POSSIBLE FROM ORGANIZED CONVECTION MOVING
SOUTHEASTWARD WITHIN THIS AXIS.  GENERAL MAINTAINED 12Z WPC QPF
CONTINUITY IN THIS AREA.


COASTAL CAROLINAS
~~~~~~~~~~~~~~~~~
A SURFACE FRONTAL BOUNDARY WILL BE SINKING SOUTHEASTWARD THROUGH
SOUTHERN MID-ATLANTIC AND INTO THE SOUTHEAST.  WIDELY SCATTERED
CONVECTION REMAINS POSSIBLE WITHIN AN AXIS OF INCREASINGLY
UNSTABLE CONDITIONS WEDNESDAY AFTERNOON/EARLY EVENING.  PW VALUES
HAVE LOWERED FROM THE PREVIOUS DAYS AS THE INITIAL FRONTAL
BOUNDARY HAS PUSHED SOUTHWARD BUT REMAIN NEAR SEASONAL LEVELS IN
THE 1.50-1.75" RANGE.  WITH WELL-DEFINED FRONTAL/PRE-FRONTAL
CONVERGENCE FORECAST ACROSS THE COASTAL SOUTHEAST WITH SEA BREEZE
BOUNDARIES ALSO POTENTIALLY AT PLAY TO REINFORCE SYNOPTIC FEATURES
IN THE AREA -- ADDITIONAL LOCALLY HEAVY TO ISOLATED EXCESSIVE
RAINFALL AMOUNTS ARE POSSIBLE FOR THE COASTAL CAROLINAS WHERE
HEAVY RAINS HAVE OCCURRED OVER THE PAST SEVERAL DAYS.  ISOLATED
2-4" AMOUNTS, ADVERTISED BY THE MOST RECENT MESOSCALE QPF
GUIDANCE, ARE POSSIBLE ACROSS COASTAL SECTIONS OF THE CAROLINAS.
MADE CHANGES TO 12Z WPC QPF CONTINUITY TO ACCOUNT FOR RECENT
SATELLITE AND RADAR TRENDS.


SOUTH FL
~~~~~~~~
A MOISTURE AXIS THAT HAD BEEN ACROSS THE SOUTHEAST OVER THE PAST
FEW DAYS WILL BE PUSHING SOUTHWARD INTO CENTRAL TO SOUTH FLORIDA
TODAY INTO TOMORROW.  THIS WILL SUPPORT WIDESPREAD SCATTERED
CONVECTION OVER THE CENTRAL TO SOUTHERN PORTION OF THE PENINSULA
WITH MODERATE TO LOCALLY HEAVY PRECIPITATION TOTALS.  THE
MESOSCALE GUIDANCE INDICATES LOCAL AMOUNTS OF 3-5" ARE POSSIBLE
WHERE CELLS MERGE/TRAIN.  GENERAL MAINTAINED 12Z WPC QPF
CONTINUITY IN THIS AREA.

ROTH

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

24HR QP VT 19/00Z
 0.01 538205 538196 538189 537185 533177 531167 527160 522154
      518152 514152 511152 504150 502155 506158 507162 500164
      497167 496174 492181 490184 490188 492196 494199 492204
      486206 472210 460214 447218 440217 434219 427220 423222
      421225 417222 417218 411213 395207 385200 382199 381204
      383208 386211 392217 395219 395223 392225 389226 382224
      366221 360224 361226 365228 373230 376232 380234 384235
      387238 392244 395250 400254 407259 410262 415263 423264
      431264 437262 442262 448260 455261 462260 467260 472262
      483275 488278 495279 500279 505281 509281 512280 514277
      515269 515265 516261 517255 517251 515242 513234 506220
      503212 504205 507202 525222 530224 534218 535215 537210
      538205
 0.01 510666 508653 504643 500634 494629 491628 487629 484631
      480635 472650 471655 469659 467664 463667 454669 449672
      451674 454675 457677 459680 465678 468679 467684 464694
      462703 461708 461715 461721 459725 456734 453756 452767
      453779 454792 458801 464796 466792 467787 475771 476767
      479762 483754 491738 498722 501712 502700 507680 509672
      510666
 0.01 522025 523008 523991 523974 523968 520964 517962 512962
      504966 486961 476962 472964 472972 470989 485980 489978
      495978 498982 500988 500995 502001 504005 508009 514016
      517026 518030 520031 522025
 0.01 492238 491233 490230 488229 486226 484223 483221 479221
      478223 479226 480229 481231 483235 486238 489238 492238
 0.01 475129 474126 471126 466125 468121 472116 472112 473109
      475106 472106 470103 471099 470095 469095 464092 462089
      459090 455087 454083 453078 451075 447072 443072 447079
      451083 451088 430099 431103 428105 419109 416118 413120
      408121 404121 402125 399128 394130 388134 382140 380144
      379150 378164 380172 384175 389178 395179 402174 408167
      414161 415165 418165 428165 435162 437161 440161 443164
      448165 451164 454162 458158 459153 462150 468147 475129
 0.01 446732 436734 431735 429740 427745 426751 423763 424771
      423777 425791 428789 430783 432771 432764 432756 434750
      436746 444738 446732
 0.01 442127 442121 439119 432121 427125 424134 421141 418149
      417155 416158 417161 423155 429151 432150 434148 437139
      440129 442127
 0.01 419024 411011 410007 407003 404994 401982 398972 391948
      386937 384927 377909 374900 372896 369893 366891 362887
      356877 352870 350867 344868 341870 339875 337884 334889
      331893 325900 318905 313907 310908 308906 298896 293887
      290878 287873 283871 280868 278863 276858 273853 272847
      273841 284831 287827 287823 281818 282814 284809 287807
      291807 302811 306813 306816 312820 317821 323819 326817
      332810 337801 341795 344791 344786 346782 351780 350775
      348771 349767 352764 355757 356746 351738 346738 342741
      336749 330758 327766 324775 319779 314780 309779 302775
      293771 290768 288762 286757 279757 274757 270758 261772
      257779 254786 250795 246805 243816 241825 241839 239847
      240857 241861 242867 245881 248890 253907 256916 258925
      258936 258943 257949 255960 259971 255976 255981 256985
      260987 266989 272989 277988 281990 283991 282993 281998
      280003 279010 277011 275009 270008 263004 258000 249000
      246003 247007 251014 264023 273030 274034 271037 256049
      252048 246048 239049 236052 233055 233061 239066 242073
      247080 254084 257086 260085 267082 270081 273077 278070
      282070 285072 289075 291076 290078 288082 284085 275090
      270097 275102 274108 277111 282113 285116 286120 290131
      294141 298148 301152 304155 311160 318164 325169 329171
      335172 340174 342180 345182 347175 348169 350165 355162
      360162 367165 370163 371158 372143 371133 370126 367121
      359114 356112 355106 355101 356095 360087 364078 365074
      366069 370059 372055 369050 363041 359037 357033 355030
      354023 354009 351002 349998 345989 345982 346977 347970
      349965 353958 365965 373970 378976
 0.01 378976 380981 381986 382990 383995 385999 388004 390007
      394009 397014 400016 404019 407021 411024 414024 419025
      419024
 0.01 408112 409105 408100 406102 404107 402109 399110 396110
      392112 390114 394115 398113 401113 404112 407112 408112
 0.01 386758 386752 384752 379757 376763 371769 365773 361778
      362782 365783 369782 372780 377774 380768 384762 386758
 0.01 372799 371796 368795 363798 360802 358803 353810 350815
      347822 348826 351826 354826 356823 359816 362813 364811
      369804 372799
 0.25 526198 526193 526190 524187 522184 521183 518182 514180
      513178 511181 512186 514188 515190 516193 519196 521198
      522201 525201 526198
 0.25 512255 513250 511244 508237 502230 499221 493216 488215
      490219 494225 500232 502240 503246 502249 501255 497255
      491250 478239 474238 471241 471245 476247 490255 492259
      496260 504260 509259 512255
 0.25 496662 495658 493656 488653 483654 480660 477668 475674
      474684 473692 469706 467716 468724 471730 472733 476735
      483721 488709 493692 494685 496676 496662
 0.25 450242 449238 448235 444237 438239 432237 427233 420233
      415232 409230 405229 400232 398236 400244 405248 408252
      413255 420257 425258 431256 435253 438248 439246 442244
      447243 450242
 0.25 412143 413141 413140 411141 409142 409143 407145 407147
      408148 409147 410147 411145 412144 412143
 0.25 392979 392971 391963 387952 382941 379936 376931 372928
      369924 365919 362919 359921 357919 353914 353907 357903
      360904 362902 360898 354890 350886 345886 341890 339895
      336909 335920 340930 347941 356948 365954 372962 380969
      387975 389979 392979
 0.25 364157 363155 361156 362158 364157 364157
 0.25 349119 349102 351092 353088 354082 351066 352054 352044
      350028 349019 345011 341006 335004 329000 325995 322990
      320982 324964 326958 330953 334945 332939 326938 318937
      312934 306929 300918 292906 289901 284898 274888 265880
      263878 262882 264890 266906 268914 271923 275937 279954
      284965 285973 288982 302005 306009 309016 308027 301030
      299034 299038 296044 297048 299050 305054 311057 312059
      312062 308070 305077 303081 300083 297084 295087 293096
      291102 289108 292114 296119 299122 303124 307125 312125
      315124 319124 325122 330120 336119 342122 347123 349119
 0.25 331800 331796 328794 325796 323798 321800 320803 319806
      318808 319810 322812 325810 327807 328805 330803 331800
 0.25 284775 282766 280763 276764 270779 266785 262792 262795
      259799 252803 251807 252813 252824 254840 255838 258837
      262831 268826 271824 270820 268817 266811 266806 268802
      274798 276790 283785 284777 284775
 0.25 266064 267062 268060 266058 264058 263058 261059 260059
      259060 258061 257063 256063 255065 254067 255068 256069
      258069 260069 262068 264067 265066 266065 266064
 0.25 255858 255856 255854 254852 254850 254848 252847 250848
      250849 249851 248853 248855 249857 249858 250859 251861
      253862 255860 255858
 0.50 487673 487666 485665 483667 482672 481676 479681 478686
      479693 482696 485694 486689 487683 487676 487673
 0.50 483700 482699 480700 480701 481702 482701 483700
 0.50 428247 427244 423241 419239 414238 411235 407235 403235
      404240 408242 410243 412245 412250 417252 420252 425251
      428248 428247
 0.50 386963 386957 384952 380943 376936 370930 367927 362925
      357932 356938 358943 364948 370954 376961 379963 384964
      386963
 0.50 350088 351080 349074 347068 346060 349045 348035 348028
      346022 343017 332011 327008 324004 320998 318992 315980
      314972 316973 319972 320964 319956 317949 314944 310941
      302931 296922 294916 290911 283903 277900 273902 273909
      275913 281926 283932 283938 285955 288960 290964 294979
      296984 298990 305001 311010 314015 316022 316030 315033
      311043 308037 306031 302032 300038 305046 314050 316052
      316057 315063 312070 311077 310083 307088 301090 299093
      298097 295103 293108 301116 304119 309122 315122 322120
      342111 350088
 0.50 346897 346896 345895 344895 343897 342898 342899 342900
      344900 344899 346897 346897
 0.50 264817 264815 262811 260810 258807 256806 254808 254812
      256814 257815 257820 257822 258824 260823 262821 264819
      264817
 1.00 378954 378952 378949 377947 377946 376945 375943 374940
      373939 372938 371938 370938 370940 370941 370943 371945
      372946 372947 373949 374952 375953 375954 377956 378954
 1.00 347085 344075 341065 341061 341055 344043 345037 344031
      339028 334027 329033 324042 322046 321051 321056 320061
      318065 318072 317084 305098 304102 304108 306112 309117
      312119 318118 325114 340104 343100 344095 347085
 1.00 315958 313952 309947 305944 301940 297935 294933 292933
      291937 292945 294958 295966 297972 303983 306988 311998
      311993 309981 306975 305968 305964 306961 310960 315958
 1.50 342098 343087 343083 341079 339071 337069 336064 337060
      337054 339045 337043 334043 327046 324053 325061 322067
      321078 320089 314092 310099 308101 307106 309113 313115
      318115 322110 327109 330107 340100 342098
 1.50 310954 308950 305948 301945 299943 296941 296947 296954
      297960 299964 303961 305958 308956 310954
 2.00 301954 301954 340096 341089 340085 338080
      337076 335072 329071 325072 323077 323085 321091 318093
      313101 310104 310107 313111 318110 321106 324104 332102
      339098 340096
 2.00 333058 333056 332054 332053 331052 329051 327051 326053
      325055 326057 327058 328059 330059 332059 333058
 3.00 335091 336088 335087 335086 334084 334083 332082 330083
      328084 328085 327087 328090 327092 327093 329093 331093
      333093 333092 335091 335091

$$





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