Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 151843
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
143 PM EST WED NOV 15 2017


PRELIM DAY 1 QPF DISCUSSION
VALID NOV 16/0000 UTC THRU NOV 17/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

...CALIFORNIA...

A POTENT AND ACTUALLY POTENTIALLY DANGEROUS HEAVY RAINFALL EVENT
WAS FORMING OVER NORTHERN CALIFORNIA. THE EVENT HAD NOT EVOLVED AS
A TRADITIONAL ATMOSPHERIC RIVER...BUT WILL BRIEFLY MEET THAT
CRITERIA THIS AFTERNOON AND TONIGHT PER THE ESRL DETECTION TOOL
BASED ON THE GFS. SNOW LEVELS ARE HIGH...MEANING A MAJORITY RAIN
AT MOST POPULATED ELEVATIONS. SYNOPTICALLY THE EVENT IS FORECAST
TO PEAK DURING A 9 TO 12 HOUR PERIOD BEGINNING THIS AFTERNOON...AS
A STRENGTHENING UPPER JET STRUCTURE TAPS INTO HIGHER PW AIR
STREAMING OFF THE PACIFIC. FORECAST AVERAGE EVENT-TOTAL RAINFALL
AMOUNTS OF 1.5 TO 3.0 INCHES (LOCALLY GREATER) AND HOURLY RATES
PEAKING ABOVE 0.75 INCHES IN FAVORED TERRAIN ALONG THE COAST COULD
LEAD TO FLASH FLOODING. CONCERN IS GREATEST IN AND NEAR THE
CLUSTER OF BURN SCARS FROM WHAT WAS SUCH AN ACTIVE FIRE SEASON
NORTH OF THE BAY AREA. THIS THREAT IS HIGHLIGHTED IN MESOSCALE
DISCUSSION NUMBER 0933.

MOREOVER...THE 5 TO 8 INCHES OF LIQUID BEING FORECAST IN THE
UPSLOPE REGION OF THE SIERRAS OVERNIGHT WOULD MEET THE 5-YEAR
AVERAGE RECURRENCE INTERVAL...MAKING THIS A QUICK HITTING AND
SOMEWHAT EXCEPTIONAL EVENT. WPC QPF NUDGED TOWARD THE 12Z
WRF-ARW...BUT OTHERWISE KEPT CONTINUITY. THE TREND RESULTED IN
HEAVIER RAIN IN THE SAN FRANCISCO BAY AREA PROPER...AND POINTS
SOUTH.


...REST OF PACIFIC NORTHWEST AND INTERMOUNTAIN WEST...

MODERATE TO LOCALLY HEAVY EVEN TOTALS OF RAIN AND SNOW ARE LIKELY
ACROSS THE NORTHERN ROCKIES FROM NW WY INTO SOUTH CENTRAL TO
NORTHERN ID. THE WEST COAST ATMOSPHERIC RIVER WILL FOCUS ON THE
SOUTH FACING SLOPES IN IDAHO AND WEST FACING SLOPES IN WESTERN
WYOMING FOR AN EXTENDED TIME TONIGHT AND THURSDAY. WPC TOOK A
SIMILAR APPROACH THROUGHOUT THE WEST...WITH THE INHERITED FORECAST
LOOKING GOOD...WE NUDGED TOWARD THE 12Z WRF-ARW. PLEASE SEE THE
LATEST QPFHSD FOR ADDITIONAL WINTER WEATHER INFORMATION.


...EASTERN / NORTHEASTERN U.S...

A WELL MODELED MEDIUM WAVELENGTH TROUGH WITH ASSOCIATED SURFACE
LOW TRACKING THROUGH THE GREAT LAKES...WILL PERFORM A SURFACE HAND
OFF TO A DEVELOPING COASTAL LOW ON THURSDAY. THE SYSTEM WAS
DRAWING ON MODIFIED GULF MOISTURE...YIELDING FAIRLY UNIFORM LIGHT
RAIN AMOUNTS JUST UNDER A HALF INCH OVER THE OHIO AND TENNESSEE
VALLEYS...WITH SOMEWHAT GREATER AMOUNTS IN THE REGION OF STRONG
HEIGHT FALLS AND CYCLONE DEVELOPMENT OVER THE EASTERN GREAT LAKES.
WARM ADVECTION AND HEIGHT FALLS WILL BRUSH ACROSS THE MID ATLANTIC
TONIGHT...SUPPORTING LIGHT RAIN. THE COASTAL LOW DEVELOPMENT AND
ASSOCIATED FRONTOGENESIS SHOULD THEN LEAD TO A HEAVIER RAIN
EVENT...ALTHOUGH STILL MODEST IN DURATION AND INTENSITY...OVER NEW
ENGLAND ON THURSDAY. THE HI-RES GUIDANCE EMPHASIZES OFFSHORE
CONVECTION...WHILE THE GLOBAL GUIDANCE AND NAM SEEM TO DO A BETTER
JOB CAPTURING THE PRECIPITATION SWATH THAT IS LIKELY TO OCCUR JUST
NORTH AND WEST OF THE DEEPENING COASTAL LOW. WPC STARTED WITH A
BLEND OF THE NAM...OUR IN-HOUSE ENSEMBLE...AND THE WPC
FORECAST...WITH HEAVIEST WEIGHT TOWARD THE 12Z NAM.

BURKE

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

24HR QP VT 17/00Z
 0.01 533198 531192 529186 527182 526174 521164 517159 516152
      505129 501116 503110 504104 505096 507089 511079 512069
      510064 506062 501064 499064 497069 495074 491088 489105
      490119 488124 482124 476123 470120 467119 463123 460127
      458123 459119 465107 462102 461094 458091 453090 449090
      444089 436083 429077 424073 420073 418074 416076 415079
      415087 415092 413094 410093 405096 401100 395107 392110
      390116 392119 396122 402124 405128 410131 412137 411141
      409141 405144 400147 397154 394159 391163 384169 378176
      373177 367177 363177 358181 356185 358191 360196 360203
      353211 351218 351225 351233 353237 355241 358244 369246
      377252 382255 389258 392261 398264 402266 407265 417264
      437260 445259 456260 468263 474263 479265 484267 488271
      493280 496283 500284 502282 509273 514261 517246 517238
      515232 510220 505213 498205 493200 488197 483198 480201
      471203 468205 464205 463201 466196 471194 480190 483189
      487190 493192 498193 500191 503191 511196 519202 523208
      526206 533198
 0.01 494787 494773 493766 491761 487751 483741 480732 479726
      480720 482715 481708 478698 482679 481675 478670 473661
      467655 461648 458646 454646 450647 447649 440655 434661
      423674 421678 417681 409676 402675 399674 395677 390678
      387681 382688 375693 364696 356698 351705 347709 345713
      344718 344723 344728 345731 347736 349739 354747 357750
      360754 364758 368758 374764 380768 384777 375792 367808
      362815 359821 357827 356832 357839 359841 362843 365841
      373837 378830 384824 391820 394817 399817 413828 428834
      435835 437837 438839 440845 433860 434864 437866 448866
      452867 455870 458879 457892 460904 461908 464910 470908
      474905 477900 482894 485885 488876 489870 488864 487860
      486853 490803 493795 494787
 0.01 446075 446072 445070 443069 441069 440069 441072 443074
      444075 446075 446075
 0.01 352976 352971 350967 350958 350946 348938 345936 340936
      337938 336943 334947 330947 325953 319969 318974 315977
      308981 300983 297983 298989 314986 322983 327983 335986
      339989 342989 348985 350982 352976 352976
 0.01 314792 313787 311785 308785 298788 289792 281797 278785
      272786 268789 258788 246790 240795 238800 235803 233807
      232812 235816 239816 247811 254806 265804 270802 274806
      277807 282806 286807 290809 293809 298807 306803 312795
      314792
 0.25 511257 511250 510242 509235 505231 500219 497213 491209
      487208 483207 477208 466211 460210 455211 451212 446213
      435212 429209 426204 423198 424190 427186 430179 432176
      435175 436172 436168 439169 443174 448177 450182 451184
      454185 459183 458171 460166 462165 466166 468172 473173
      478174 484176 495179 503180 508183 514185 514179 509168
      512157 509152 505148 499144 495141 491137 486133 479131
      476131 475134 476139 478139 483143 486149 490151 495154
      494156 475152 466146 455148 450145 446140 442130 444125
      448122 452114 453107 455102 452097 441092 432089 427087
      425087 424089 427101 422105 418110 414108 411103 409101
      406103 403108 401113 405116 410117 416120 419125 421132
      422138 422143 420145 415147 409150 405155 403162 400167
      396170 390171 387173 383176 385181 395188 394191 391191
      387189 382185 375183 367181 362182 361187 362190 365197
      367201 367205 366207 358214 356219 357226 357232 361238
      366239 373243 385241 392241 397244 402248 410249 430250
      441251 447252 453251 464250 469250 476251 481255 484258
      489262 494266 498270 500268 501264 498257 498253 499248
      501249 504253 507258 511257
 0.25 482776 482771 481765 478757 473751 467748 461747 453747
      450746 447744 442738 440733 443726 447718 451713 455705
      457696 457687 457677 456672 454669 449666 442671 437676
      428686 416697 412697 409695 404691 397690 390693 380703
      373707 365708 356708 351713 350717 350723 354728 361740
      368741 372736 387730 393725 396724 397727 398733 399736
      403736 410737 418738 422739 422744 421753 422758 422763
      421768 419771 415778 413785 416793 420801 423802 425798
      426793 426785 426782 427779 430778 436781 438786 437792
      435794 430801 428810 428817 430820 433822 448824 451826
      453830 453837 452842 449848 453848 454845 456842 459841
      465843 470842 472838 475830 477823 478813 478799 479789
      482776
 0.25 470880 471875 470870 470865 470860 468857 465857 464860
      462864 462869 463873 464878 465881 467883 469883 470880
 0.25 302798 302795 301794 299794 297795 295795 293796 292797
      291797 290799 290801 290802 291803 292804 294804 296804
      298803 298802 300801 301800 301799 302798
 0.50 508251 508245 506240 504236 502232 500227 498222 495219
      493225 494230 496236 498240 501243 503247 506250 508251
 0.50 494259 494256 494253 492249 491245 490243 487241 484245
      486249 487252 488254 491258 493259 494259
 0.50 500170 500167 498165 493163 490161 485159 480158 475157
      472158 472163 476164 480168 483171 487173 492174 495174
      499171 500170
 0.50 499152 498149 496146 493143 492141 490139 487137 484138
      486141 487144 489147 491148 494150 496151 499152
 0.50 489218 489216 489214 487213 485213 484213 482212 480213
      479215 478215 478216 480218 481218 483219 485220 486220
      488220 489218
 0.50 482244 481239 479233 476231 474232 470234 467234 465232
      460232 454233 448233 439234 439232 443229 447229 452227
      456226 461229 465226 467221 469218 466215 461214 452216
      440215 430216 421220 420224 423228 426230 426232 420231
      415229 414224 416218 416214 413213 411212 410210 410205
      412204 412201 408196 404194 399195 392194 388191 377185
      364182 363185 363189 366194 371203 359219 359231 363235
      368237 374240 378239 383237 389236 393235 398239 402244
      406246 416246 428248 437247 443248 449247 467244 476245
      482244
 0.50 471816 471801 471793 469787 465784 462785 459787 456791
      449796 443803 438810 438813 444814 452814 456815 459820
      461824 464827 468826 470822 471816
 0.50 447680 446678 443679 438684 430695 426699 420703 416708
      411712 406717 404719 404725 409729 415731 419730 425727
      436719 442715 446710 448702 447692 447680
 0.50 452171 453164 453157 448150 443142 439134 437130 435126
      436121 439120 442121 446120 448116 450109 448099 444096
      440094 435094 431090 428089 426088 425091 429099 428103
      425106 421116 420119 421124 426132 428142 429149 431154
      435161 443166 450170 452171
 0.50 432169 431166 429164 428164 426165 426166 426167 426170
      427172 429171 430170 432169
 0.50 419175 417165 419161 420157 419153 415151 411153 409157
      408166 408169 406171 402172 400176 399179 399183 403184
      406183 409175 412173 414175 419175
 0.50 405229 406224 406221 402221 400221 397221 393220 391220
      393223 394225 396228 397229 400230 402228 402223 404224
      405229 405229
 0.50 398703 398698 395696 391698 387703 383708 379711 376717
      379723 384725 388721 392717 394711 396705 398703
 0.50 360718 359718 357718 356719 357719 359718 360718
 1.00 463221 462220 461219 459219 458219 458222 459222 460223
      461223 462222 463221
 1.00 450222 447220 442219 438220 433219 429220 425221 424223
      425225 430228 431229 435227 439225 444226 448225 450222
 1.00 446155 445151 442147 440143 439139 436135 432135 431142
      431147 432153 435157 439158 442158 446156 446155
 1.00 440704 439698 437697 434701 430704 427707 424710 419713
      418715 420718 425715 430714 434712 438709 440706 440704
 1.00 446114 446108 444104 443100 439098 435098 433095 429092
      431099 431106 427113 425116 425122 427123 429120 431116
      434115 441115 446114
 1.00 427242 426237 423237 421235 418235 416234 413234 411236
      408238 408239 411242 415242 418243 422244 425244 427242
 1.00 412221 404206 399200 391196 384191 377187 369185 367187
      369191 375207 373211 369212 366214 363218 362225 361229
      364232 370236 374237 378235 383232 388232 391230 391225
      389221 389218 390216 394216 403218 411222 412221
 1.50 430224 429223 427223 429224 430224 430224
 1.50 439153 440151 439149 439146 439144 438141 437140 436140
      435141 434143 434145 433147 433150 434152 434153 436155
      437156 438155 439154 439153
 1.50 444111 444108 444107 443106 442104 441103 439104 437104
      435105 435107 435109 437111 438111 440111 442112 443112
      444111
 1.50 423241 422240 421238 420238 419237 418237 417239 417240
      419240 421241 422241 423241
 1.50 407215 404209 399203 386194 380190 373187 370189 371192
      375200 378205 379209 379215 373213 367215 365218 364222
      366229 371234 375235 378233 389227 386219 389215 393215
      397216 405217 407215
 2.00 404214 404211 402208 398203 391199 386196 380192 377190
      373190 374195 377201 380207 381215 378217 375217 373215
      369215 365219 365223 367226 371231 377231 382229 386224
      384217 389213 395214 401216 404214
 3.00 401213 400209 397205 394202 389200 386198 381195 378193
      376194 378199 380201 382207 384210 389211 394213 400214
      401213
 3.00 382225 383223 382222 380221 379221 378222 377222 375222
      373221 371221 371222 371223 371224 372226 373227 374228
      376229 377229 378228 379228 380227 382225 382225
 4.00 399213 399209 397206 396204 392202 391201 387200 384199
      382200 383202 384205 385207 388209 391211 393212 396213
      399213
 5.00 398211 397208 396206 395205 394204 392203 391202 389202
      387201 386203 386205 386206 388208 390209 391210 393211
      395211 396212 398211
 6.00 397210 397209 396208 395207 394205 392204 390203 389203
      388203 388205 389206 390207 391208 392209 393210 395210
      397211 397210

$$





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