Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 201809
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
208 PM EDT FRI OCT 20 2017


PRELIM DAY 1 QPF DISCUSSION
VALID OCT 21/0000 UTC THRU OCT 22/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

...NORTHWEST INTO THE CENTRAL AND NORTHERN ROCKIES...

BEHIND PROGRESSIVE UPPER TROF MOVING ACRS THE PAD NW/NRN
INTERMOUNTAIN REGION FRI/FRI NIGHT..THE NEXT ATMOSPHERIC RIVER
SURGE WILL ACCOMPANY QUICK MOVING WARM FRONT THAT IS FCST TO
APPROACH THE WA/OR COAST BY SAT MORNING IN RESPONSE TO IMPRESSIVE
150KT E/W UPPER JET PUNCHING EWD THROUGH THE SRN GULF OF AK/NRN
PAC.  MODELS CONTINUE TO SHOW RATHER GOOD RUN TO RUN CONTINUITY IN
DIRECTING 50 TO 60 KT 85H FLOW INTO THE WA/OR COASTS BY SAT
MORNING ACCOMPANIED BY PWS CLIMBING TO AT LEAST 1.25 INCHES
LEADING TO IMPRESSIVE MSTR FLUX VALUES.  THIS IS EXPECTED TO BE A
RATHER LONG DURATION HEAVY RAIN SCENARIO WITH RAINFALL RATES
INCREASING RAPIDLY ALONG THE COAST AND COASTAL RANGES BY 12Z AND
CONTINUING BEYOND THE DAY 1 ENDING PD.  STGR INITIAL ISENTROPIC
LIFT WILL BE FOLLOWED BY EQUALLY STG OROGRAPHIC FORCING GIVEN
MOIST WLY FLOW ORTHOGONAL TO N/S COASTAL RANGES/CASCADES.  FOR QPF
AMOUNTS...GENLY LEANED TOWARD A CONSENSUS OF HIER RES MODEL
GUIDANCE GIVEN FAVORABLE TOPOGRAPHIC DETAILS WHICH WOULD SUPPORT 2
TO 4"+ AMOUNTS OVER PORTIONS OF THE OREGON AND WASHINGTON COASTAL
RANGES/OLYMPICS EWD INTO THE CASCADES.  WHILE THE MTNS OF WRN
WA/OR WILL TEND TO BE FAVORED FOR HEAVIEST PCPN AMOUNTS IN THIS
PATTERN...MDT PCPN AMOUNTS ARE EXPECTED FARTHER EAST INTO PORTIONS
OF THE NRN INTERMOUNTAIN REGION/ROCKIES WITH INCREASINGLY MOIST
WLY UPSLOPE CONDS.  SNOW LEVELS ARE EXPECTED TO RISE RAPIDLY BY
SAT MORNING SO THERE WILL BE SOME RUNOFF CONTRIBUTION FROM SNOW
MELT..THOUGH THE EXPECTED HEAVY RAIN ALONE WILL LIKELY CONTRIBUTE
TOWARD SOME FLOODING CONCERNS THAT WILL CONTINUE BEYOND THE DAY 1
PD.

...UPPER TX/CNTL GULF COAST...

MODELS CONTINUE TO STRUGGLE HERE WITH REGARDS TO ANY PRIMARY QPF
FOCUS.  BATTLE APPEARS TO BETWEEN MID/UPPER FLOW WHICH WANTS TAKE
CONVECTION ALONG THE UPPER TX COAST AT FORMED EARLY FRI ALONG
NARROW INSTABILITY/MSTR AXIS SLOWLY NEWD..AND BROADENING LOW LEVEL
SELY FLOW WHICH EXPANDS LOW LEVEL INFLOW OVER A LARGER AREA ACRS
THE UPPER TX COAST AND KEEPS FOCUS FOR RAIN MORE OVER THAT REGION.
 NO CLEAR CONSENSUS EXISTS AT THIS TIME THOUGH SHORT TERM TRENDS
WOULD SEEM TO DISCOUNT THE 12Z CANADIAN GEM SHIFTING HEAVIER RAIN
FOCUS NEAR THE LA/TX BORDER.  WITH TIME..MODELS TO SHOW A GRADUAL
WWD EXPANSION OF THE SFC RIDGE ALONG THE LA/TX COAST..WHICH SHOULD
LEAD TO LESS FOCUSED LOW LEVEL CONVERGENCE THIS PD ALONG THE TX
COAST.  A CONSENSUS OF HI RES GUIDANCE INCLUDING RECENT HRRR
GUIDANCE WOULD APPEAR TO BE A GOOD MIDDLE GROUND APPROACH GIVEN
THE SHORT TERM TRENDS.   A SEPARATE ESELY INFLOW CONVERGENCE AXIS
IS EXPECTED TO SETUP ACRS PARTS OF THE CNTL LA COAST WITH
INCREASING PWS LIKELY LEADING TO SOME MDT PCPN AMOUNTS OVER SE LA.


...FLORIDA...

NO SIGNIFICANT CHANGES EXPECTED TO THE CURRENT POST FRONTAL EAST
NORTHEASTERLY LOW LEVEL FLOW REGIME ACROSS FL DAY 1.  SCATTERED
SHOWERS LIKELY TO CONTINUE OFF THE WESTERN ATLANTIC AND ACROSS THE
PENINSULA THIS PERIOD.  CONFIDENCE LOW WITH QPF DETAILS IN THIS
PATTERN---WITH LIGHT TO MODERATE AREAL AVERAGE AMOUNTS DEPICTED
AND POTENTIAL FOR ISOLATED HEAVY TOTALS WHERE OCCASIONAL E/W RAIN
BANDS SETUP.

...UPPER MS VALLEY SWD INTO THE SRN PLAINS...

AS THE WESTERN U.S. TROUGH PUSHES EAST A COLD FRONT WILL MOVE INTO
THE PLAINS FRIDAY NIGHT AND CONTINUE TO ADVANCE GRADUALLY EWD
DURING THE DAY ON SATURDAY.  STRENGTHENING 85H SSWLY FLOW WILL
ALLOW PWS TO RAPIDLY INCREASE THROUGH THE CNTL/SRN PLAINS SAT AFTN
WHICH ALONG WITH INCREASING LI`S WILL SUPPORT AN EXPANDING
CONVECTIVE RAIN THREAT SAT AFTN FROM THE UPPER MS VALLEY SWD INTO
THE SRN PLAINS ALONG THE COLD FRONT.  HEAVIER RAIN AT THIS TIME
WOULD APPEAR TO BE FROM ERN KS SWWD INTO OK WITHIN FAVORABLE RT
ENTRANCE REGION OF THE STRENGTHENING UPPER JET EAST OF THE UPPER
TROF.  WITH THE NAM TRENDING TOWARD PREVIOUS RUNS OF THE GFS/EC
WITH STGR ENERGY DIVING INTO THE BASE OF THE LONGWAVE TROF..THERE
IS REASONABLY GOOD CONSENSUS WITH QPF WITH THE EXCEPTION OF THE
LOWER RES NAM WHICH APPEARED TO BE A DRY OUTLIER.  HEAVIEST RAINS
AREA LIKELY BEYOND THE DAY 1 PD..BUT GIVEN CURRENT TIMING...GENLY
AGREE ON AN AXIS OF .50 TO 1" RAINS FROM ERN KS INTO PORTIONS OF
NRN OK WITH ISOLD HEAVIER AMOUNTS PSBL WHERE BRIEF TRAINING OR
STGR DISCRETE SUPER CELLS DVLP DURING THE AFTN.


SULLIVAN


GRAPHICS AVAILABLE ON THE WEB AT
WWW.WPC.NCEP.NOAA.GOV/QPF/QPF2.SHTML

24HR QP VT 22/00Z
 0.01 461329 470330 476330 482327 486321 488318 490312 491300
      490291 492288 495288 500290 507289 510288 512284 516278
      519275 524261 522257 523250 525245 526239 534215 532205
      531194 531189 530184 527174 516162 509156 507153 505150
      507149 510147 508143 506135 505123 505118 509118 517119
      524115 528108 529102 530093 531079 528072 517061 510061
      505062 503060 487050 483049 482047 480050 481054 487059
      489063 490068 491079 491087 490090 488091 481094 485101
      489110 492120 493128 493132 490132 483128 479126 475125
      470123 468125 469134 470140 472142 474143 479144 483145
      483149 480148 472146 467139 464131 462129 459131 453131
      450134 444138 447141 444144 439143 435143 431147 422147
      418154 416158 417163 418169 416177 416183 417188 419197
      418204 417205 416202 413195 409199 411207 413210 417210
      419210 420213 419216 418217 396236 398244 401252 407259
      410268 413272 414276 412286 414296 418304 429313 440320
 0.01 521242 522238 521234 520231 517226 516222 514217 510218
      508220 511223 514226 515232 516239 518242 521242
 0.01 527941 524932 523924 522919 521915 520913 516913 505913
      498912 496908 496901 495894 496887 498875 498868 496865
      489861 485861 482867 476872 471880 468884 465887 456900
      451906 444909 435909 428909 424911 424916 422920 419928
      404936 376956 362963 348970 335980 331982 328986 323993
      313004 307010 304019 304025 305027 307027 315023 323019
      332015 345005 350001 357997 363994 372996 376997 380995
      389993 391991 394991 399991 403991 406994 410996 411001
      409006 406009 401015 398018 395020 393025 394030 405031
      409032 408038 410042 413043 419046 424046 427045 432045
      434043 441037 446028 451018 453014 456013 463008 475999
      480995 488991 496988 500985 504983 510978 514975 515971
      522955 525945 527941
 0.01 487967 488961 488957 486957 483955 479955 475956 474959
      469960 466962 458963 454966 447966 442969 435973 430978
      425983 423986 422992 426993 430991 434987 448983 465983
      469983 474982 477981 479979 485974 487971 487967
 0.01 478057 476053 473051 463049 456052 451061 450066 448072
      443072 441074 446080 451080 455079 462075 467070 471068
      474064 478057
 0.01 463112 463104 460101 450095 445093 441093 438095 435095
      430092 428091 426093 429099 430101 428103 423105 421107
      426110 429110 431113 431116 434114 437116 441119 446119
      450114 455113 460114 463112
 0.01 425063 425058 423055 414054 405053 399054 387062 383062
      380065 375063 369062 366063 368066 372071 372080 379083
      383083 384080 388081 391084 394091 397093 400092 407089
      411084 415077 420071 423065 425063
 0.01 410119 408114 410108 409103 407105 403109 400111 396112
      392114 390116 394117 397115 403116 406119 408121 410119
 0.01 374051 374050 372050 370050 368052 367052 365053 363054
      361054 363054 365054 367054 368055 368054 370053 372053
      374051 374051
 0.01 343171 342170 341168 339168 337167 339170 340172 340173
      341172 342171 343171
 0.01 353919 352915 348912 339909 324902 309894 297884 291880
      286878 282875 276869 270867 260868 259873 260878 258887
      260895 270909 275913 279917 283917 288918 290921 291927
      290930 287930 280933 277936 274939 274941 272945 268947
      265951 261957 261960 264964 266966 270969 278974 282976
      286977 295977 306977 315975 323971 328967 330962 334959
      341954 347947 346936 350926 353919
 0.01 336169 335169 334169 332166 330166 328165 327165 328168
      330169 332169 333169 335170 336169
 0.01 303817 303810 303804 302798 301793 297791 294794 292798
      290801 291807 292811 295815 297817 303817 303817
 0.01 267773 261766 259764 253765 241766 234771 230773 225777
      219782 218786 220792 224801 228825 232834 234838 237840
      246843 250845 254844 263839 265829 269810 270803 268797
      266794 264788 266778 267773
 0.25 517270 518260 516254 510239 505226 501215 498209 493205
      489200 485194 474189 471184 468178 465172 460169 459164
      462162 466163 470165 473164 475160 476157 474155 471150
      468147 465145 461144 457149 452154 449155 446153 440150
      438151 437155 437162 438169 440174 442178 436181 432183
      430186 432194 434198 441208 448211 445213 442213 436209
      434212 430210 426209 423216 420221 420226 424230 425232
      423234 420232 413231 409232 408235 402242 409246 413250
      423275 425281 425287 425293 427296 428298 432299 438301
      445304 450309 453311 456312 461311 465308 471294 474288
      475283 477275 479270 483271 489273 495277 499280 504281
      517270
 0.25 494192 494189 494187 494186 492184 491184 490185 490186
      491188 492190 493191 493192 494192
 0.25 485233 486230 485228 484227 483227 482226 480225 479225
      478225 479226 480228 480230 480231 481234 481235 483234
      485233 485233
 0.25 488136 487136 486134 485133 484132 483132 482133 481133
      479134 478134 477135 476136 475137 474138 475139 477139
      478139 479139 480139 482139 484139 485139 487139 488136
 0.25 462196 461194 459193 457193 456194 455196 454198 455201
      456200 457199 458198 460198 460197 462196
 0.25 474917 472914 468913 462914 458916 452920 445925 439930
      429933 426934 421935 414938 400947 394950 387954 373963
      366967 361972 347982 342987 337993 334997 335999 338998
      345993 352990 360988 369986 375981 386969 392964 400961
      404959 407960 409961 412959 419957 423954 428952 432950
      435947 440942 445937 448935 454934 462930 467927 472922
      474917
 0.25 429187 428186 427185 425185 424186 425188 426189 428187
      429187
 0.25 413071 412068 411068 410068 408068 407070 407072 407075
      408076 410075 411074 412073 413071 413071
 0.25 405079 406072 403067 401065 398060 395062 392066 390070
      390073 392075 395073 397076 400081 403081 405079
 0.25 333928 330925 323924 319923 315920 308916 303907 299899
      293893 289891 285893 283898 285902 292908 297914 304922
      306925 306929 294931 288935 284938 282939 282943 287950
      291952 297952 305949 312943 315940 319938 328934 333928
 0.25 261801 259795 255793 250796 247800 244805 241809 240814
      242816 244815 250812 254809 258807 259805 261801
 0.50 504273 503268 501263 496252 492241 489237 486235 484239
      480235 478229 476226 477222 482223 487224 490228 491233
      494238 497242 501246 505246 505240 504235 501224 497213
      492210 488206 484202 478202 471204 456210 449214 439213
      431216 422221 422225 426229 429233 428235 423235 417234
      412235 410236 410240 416246 419251 422255 430275 434284
      433290 436294 446300 448302 451303 455299 460292 462284
      462277 461264 465258 469255 479256 483256 488258 496269
      500273 504273
 0.50 470158 471155 470154 469153 467153 465153 464154 465156
      465157 467157 468158 470158 470158
 0.50 463181 462176 459175 457176 455174 453170 451165 447163
      444167 445172 448175 449180 441183 439195 439200 442204
      444205 447202 452194 453188 457185 460183 463181
 0.50 398956 395953 392954 386957 380961 374965 370970 365976
      363980 364983 368983 371981 375976 380971 386966 391961
      396957 398956
 0.50 317932 314932 312934 305933 299933 294934 290938 287943
      290948 294949 297948 301944 305940 310938 315935 317932
 0.50 299907 299905 299904 298903 297901 295899 294899 294901
      295903 295904 296905 297908 299909 299907
 0.50 258803 257801 256799 255799 253799 253800 252802 252804
      254805 256805 258804 258803
 1.00 494256 493255 492253 493256 493257 494256
 1.00 485217 484212 481207 476207 472211 463211 454214 445216
      439216 436218 426221 425224 429228 433231 435233 433237
      430240 427238 425237 419236 416236 415239 420242 421246
      425250 432252 436252 442253 452251 458246 462243 468242
      473244 478243 480241 479235 478232 475231 470230 468226
      470222 474218 483218 485217
 1.00 461228 460227 456226 453226 451227 449229 447230 444230
      447231 448231 452230 454230 456229 459228 461228
 1.00 297939 296938 295939 294940 293941 293943 294945 296944
      296943 297941 297939 297939
 1.50 478238 478236 478234 476233 474233 473233 472234 471236
      471238 472240 473240 475240 477239 478238
 1.50 480216 481214 481211 481210 479209 477209 477210 475212
      474214 475215 477216 478216 480216 480216
 1.50 472216 469214 465215 460214 458215 449217 442216 436220
      429222 429226 433229 435231 437235 435239 438243 443244
      458241 465239 466234 462232 457231 450233 442233 438230
      440227 442227 446228 449227 455223 462226 468222 472216
 1.50 428243 428241 427240 426239 424239 423238 421237 420238
      419240 420241 421243 422244 423245 425245 427244 428243
 2.00 468220 469218 468215 466216 466217 465219 466221 467220
      468220
 2.00 465236 464233 463233 461235 459234 454233 450234 446234
      443235 439236 438239 440241 445242 449241 453240 457239
      460236 465236
 2.00 463223 463218 460216 458216 454216 450219 445217 441217
      438221 439224 442225 447227 450225 453221 458224 463223
 2.00 436228 435226 433226 433224 432224 430224 432225 433227
      435228 436228
 2.00 426242 426241 424240 423239 421240 422242 424243 426242
      426242
 3.00 459222 460220 459218 457219 456218 454218 456219 457220
      458222 459222 459222
 3.00 452238 451236 450235 448235 447236 446238 447239 449239
      450239 451239 452238
 3.00 448224 449222 448220 447220 445220 443220 442220 443221
      445222 446223 447224 448224 448224

$$





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