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Quantitative Precipitation Forecast (QPF) Discussion
 
(Caution: Version displayed is not the latest version. - Issued 0543Z Dec 20, 2014)
 
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Abbreviations and acronyms used in this product
 
Geographic Boundaries -  Map 1: Color  Black/White       Map 2: Color  Black/White


QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1243 AM EST SAT DEC 20 2014


PRELIM DAY 1 QPF DISCUSSION
VALID DEC 20/1200 UTC THRU DEC 21/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1...

...PAC NW/NRN INTERMOUNTAIN REGION...

A POWERFUL 150+ KT E/W UPR JET WILL TAKE AIM AT THE PAC NW COAST
THIS PD AND WITH IT WILL COME A SIGNIFICANT HEAVY TO EXCESSIVE
RAINFALL EVENT FOR MUCH OF THE COASTAL RANGES AND CASCADES. 
MODELS SURPRISINGLY SEEM TO HAVE HAD A GOOD HANDLE ON THIS SYSTEM
FOR THE PAST SEVERAL RUNS..AND CONTINUE TO SHOW RATHER GOOD MASS
FIELD AGREEMENT.  SATL INDICATES A DEEP/LONG MSTR FETCH EMANATING
FROM THE SUBTROPICS BEING RAPIDLY DIRECTED INTO COASTAL AREAS OF
WA INTO NRN CA ON SAT.  LEAD EMBEDD S/WV BRINGS LOW PRES AND ASSOC
COLD FRONT TOWARD COASTAL AREAS BY LATE SAT..BUT LITTLE IN THE WAY
OF DRYING IS EXPECTED BEHIND THE SYSTEM AS WAA LIFT QUICKLY ENSUES
SAT NIGHT WITH ANOMALOUSLY HIGH MSTR TRANSPORT 3-4 STDS ABOVE
NORMAL CONTINUING TO FOCUS ACRS THE PAC NW COAST..ESPECIALLY OVER
OREGON.  THE DEEP LAYERED AND VERY STG WLY FLOW WITH 85H WINDS
INCREASING TO 40-50 KTS WILL LEAD TO VERY STG OROGRAPHIC LIFT
THROUGH MUCH OF THE COASTAL RANGES INTO THE CASCADES.  LEANED
HEAVILY TOWARD SSEO MEAN AND CONTINUITY TO SMOOTH OUT SMALL
MESOSCALE DIFFERENCES WHILE MAINTAINING BETTER OROGRAPHIC DETAIL. 
THE FCST AMOUNTS COMPARE FAVORABLY WITH DOWNSCALED REFORECAST GFS
AMOUNTS WITH AREAL AVG AMOUNTS OVER PORTIONS OF THE WA/OR/NRN CA
COASTAL RANGES INTO THE WA/OR CASCADES EXPECTED TO FALL IN THE 3
TO 5 INCH PLUS RANGE THIS PD.  SNOW LEVELS ARE EXPECTED TO RISE
WITH THE INCREASED PAC ONSHORE FLOW/WAA AND THE COMBINATION OF
EXPECTED VERY HEAVY RAINFALL AND SNOW MELT WILL LIKELY LEAD TO
RUNOFF ISSUES OVER LOWER ELEVS OF THE CASCADES AS WELL AS OVER THE
COASTAL RANGES.  FARTHER E...EXPECT MOIST DEEP LAYERED WLY FLOW TO
BRING SIGNIFICANT QPF AMOUNTS EWD INTO THE NRN INTERMOUNTAIN
REGION WITH SIGNIFICANT SNOWS PSBL OVER THE HIER ELEVS.  MODELS
QPFS WERE REASONABLY SIMILAR HERE BUT AGAIN LEANED TOWARD HI RES
GUIDANCE FOR BETTER TERRAIN DETAILS.  SEE QPFHSD FOR DETAILS ON
WINTER WEATHER.

...SE U.S...
GENLY LIGHT PCPN AMOUNTS ARE EXPECTED ACRS THE SE TDA AS
OVERRUNNING PATRN WEAKENS IN RESPONSE TO FLATTENING S/WV TROF
MOVING RAPIDLY TOWARD THE CAROLINA COASTS BY EARLY SAT AFTN. 
FRONTAL BNDRY IS EXPECTED TO LINGER ACRS THE NRN GULF SO CAN'T
RULE OUT PERIODIC LIGHT RAINS ACRS THE ERN GULF INTO THE SE
U.S..BUT AMOUNTS SHOULD REMAINS GENLY LESS THAN .25 INCH AREAL AVG
WISE.

SULLIVAN

GRAPHICS AVAILABLE ON THE WEB AT www.wpc.ncep.noaa.gov/qpf/qpf2.shtml


24HR QP VT 21/12Z
 0.01 525254 525249 526243 528233 536217 538213 539208 537199
      535190 531181 529172 525166 514154 507148 501143 495138
      491132 486126 480123 472120 480117 484116 488117 496118
      501113 503111 501108 488100 485098 482099 475101 472103
      467102 463101 460099 453094 445093 438093 433093 431091
      424088 426096 425101 422103 419107 420108 420111 417111
      412108 410104 407101 403107 390116 390119 392123 396129
      397133 396139 394149 396157 397161 396165 394170 394175
      395181 395187 395195 389194 380190 379193 375196 384220
      377222 375223 376226 378230 378235 380243 396269 406272
      413274 421272 426270 430269 434270 440274 458280 467283
      474288 483292 488296 499302 505307
 0.01 520049 521041 520035 515026 506011 501003 499997 499990
      489975 489972 492973 494970 494964 487944 484939 487940
      491942 494940 496936 498931 497923 496919 494907 490898
      489892 488884 483879 475897 472900 470905 467912 460933
      461940 462947 464950 476963 483968 485969 484971 481972
      478977 479982 484990 489999 490006 491010 497031 499036
      501040 503044 507046 510048 514049 520049
 0.01 451667 449664 448665 446668 443670 442673 440675 437677
      436678 434681 435684 438683 440681 442679 444677 446674
      448672 450669 451667
 0.01 431696 430691 426686 419683 413683 410688 409700 410705
      407709 403713 402718 404720 408717 411711 415708 420710
      423713 425715 428715 430711 432705 431701 431696 431696
 0.01 428923 426921 426916 424909 422902 418898 413898 411898
      411903 410905 411908 407912 408917 410922 412924 416924
      421928 426928 428923
 0.01 416076 414066 416064 413061 407058 398057 393061 389066
      387070 386074 385077 388079 393082 396085 399085 402078
      410077 416076
 0.01 373815 371813 368813 361816 358818 355817 352813 351809
      349802 347798 347793 346787 346781 348774 349765 352758
      353754 353750 348744 339732 336730 332729 327729 321734
      317739 312743 309746 307750 305757 305767 306775 306786
      306797 304803 300808 297816 283840 280856 280861 282865
      282875 279882 274888 267900 266907 266912 267914 269918
      272919 270926 259954 258964 255969 254974 254979 259984
      266983 272979 276974 278966 279963 278960 277957 278954
      281947 283939 286918 295910 306902 311896 315890 325861
      329855 334851 339845 345840 359834 364831 369826 373815
 0.25 521272 519260 517251 516240 514228 512223 513215 516206
      519201 519194 517182 513174 508167 504159 500149 489135
      484129 475127 472126 470128 469131 471141 468143 464141
      456136 443142 440140 437140 433140 431137 429132 430129
      433127 439122 443122 447120 450117 450113 447106 454105
      454100 451097 444100 441101 436100 430096 431100 431104
      429105 425105 423107 423112 419114 410115 408117 410121
      412123 416124 418128 417132 415136 413142 411146 408148
      405152 403156 405167 406178 413183 419187 427192 430194
      432198 435206 429205 427201 423198 418198 415199 411201
      409205 406208 402207 395203 388202 387205 388207 391210
      397217 400221 398224 391226 384228 382231 384234 395247
      402252 409257 414260 420261 425261 428260 441255 448253
      456251 464253 473258 479264 484271 489279 495285 504291
      511294
 0.25 478147 476146 476148 478147 478147
 0.25 465201 467199 466197 466195 465194 464193 463192 461192
      459192 457192 456194 456197 456199 458201 460201 461202
      462203 463204 464204 465203 465201
 0.25 456120 455118 453117 453120 455121 456120
 0.25 418227 418225 418224 417225 417227 418227
 0.25 420216 421214 420211 418213 418216 419217 420216
 0.25 341762 341753 339746 337743 335743 331743 324743 319747
      316751 313757 312762 311770 311777 312786 315791 319794
      323797 327798 330796 333792 336787 339775 341762
 0.50 511281 513273 514265 514261 514253 512240 511234 509228
      505218 500206 498203 493199 489196 485193 480193 476197
      470203 466207 460205 456209 452209 448211 443212 432211
      424203 420201 419204 423215 420219 420224 421228 423229
      425232 423232 418230 415227 416219 415216 412215 407216
      403213 399210 396210 396212 399217 403219 405223 403227
      393228 389231 388235 395242 403248 413253 419255 424256
      433254 451249 462248 470251 479258 485266 492276 499284
      502286 506285 511281
 0.50 491183 493178 493172 492163 489157 482154 476155 472150
      468145 461142 457142 455143 452149 448150 444148 439145
      433145 427142 421139 418142 419147 420150 418152 411155
      408151 406152 405156 409156 412164 423167 424170 427172
      432173 436173 439175 439180 438183 436187 437190 437195
      439199 443203 446204 448201 452196 456189 461187 465182
      469177 475175 477177 478181 480189 484189 487188 491183
 0.50 493148 492144 490139 487135 482133 477133 474130 471130
      471135 472139 473141 478139 480140 485142 488146 489150
      493148 493148
 0.50 481226 480226 479225 479226 480227 481226
 0.50 464171 463170 463168 462167 462166 461164 459164 457164
      457165 457167 456169 456171 457172 458173 459172 460172
      462171 463171 464171
 0.50 445116 446111 445108 441105 435105 430108 426109 430111
      424113 419115 417116 418118 424120 429118 434116 440115
      443117 445116
 0.50 429187 430185 429184 427184 425185 425186 425187 426188
      428188 429187
 0.50 420183 421181 421178 421176 421175 420173 419173 418175
      417177 418180 418181 420183 420183
 0.50 335773 335768 334763 331756 329752 325752 320758 318764
      317772 318783 320789 323791 326790 330788 332785 334778
      335773
 1.00 509254 508244 506238 505234 497216 493209 486203 482202
      478203 471208 457212 449213 445214 441213 434216 426218
      422219 421224 423227 428229 432231 434234 427235 418232
      414230 412226 413219 410220 409226 407231 403232 399232
      397234 394237 396240 403246 413248 421249 429249 437247
      452245 460243 469244 476248 480251 483254 492269 499276
      501277 504273 504268 502260 509254
 1.00 497247 496246 495244 493244 492245 493246 494247 496247
      497247
 1.00 493238 491233 490228 487224 483222 480221 476221 473224
      472226 477228 480231 482236 486238 489236 491237 493238
 1.00 485161 484158 483158 482157 481158 480159 479160 480161
      481162 483163 485162 485161
 1.00 474161 472158 470155 469153 467151 466149 462148 460148
      459153 460155 463158 465159 467162 468165 471167 473163
      474161
 1.00 463181 464177 462174 458175 454172 453166 452160 446157
      443154 440150 434150 431154 433160 436164 444170 448174
      450180 443183 440186 441189 444190 448189 453187 461183
      463181
 1.00 443111 442109 440109 438109 437110 438111 440111 442112
      443111
 1.00 418161 418160 416159 414160 416162 417162 418161
 1.50 501269 500264 499261 497255 495251 493248 490244 487242
      485243 486249 488254 490257 492263 495267 498270 501269
 1.50 501235 500232 499229 498226 497225 497223 496222 495220
      493222 493225 493227 493230 494233 494235 495236 496237
      497237 498237 499236 501235
 1.50 489219 489213 487209 484206 481204 479204 472208 470211
      465211 435217 428219 423219 422223 424226 428228 436232
      443228 447228 451227 454225 459227 461230 459230 452232
      444233 430238 412231 405236 398236 397239 399241 402243
      410244 420246 429246 459240 463239 466239 470240 474244
      479245 482243 480234 478230 475230 472231 469232 467230
      465229 468227 470223 473221 489219
 1.50 461180 461176 461175 458177 456178 454176 453172 451170
      449170 449174 451177 453178 454181 457184 459182 461180
 1.50 450185 450184 449182 448182 446184 446185 447187 448187
      450186 450185
 1.50 445186 444186 443185 442186 442187 444186 445186
 1.50 442161 441159 441157 439156 438156 437155 436156 435157
      435158 437160 438162 440162 442162 442161
 2.00 499266 499263 497260 496257 495254 493251 491249 489247
      487246 489249 489252 490255 491258 493261 495264 497266
      499266
 2.00 486215 483209 480206 476207 472211 467212 461214 454214
      448215 442215 431219 425220 422224 425226 432229 437229
      439226 441226 448227 454223 458225 462227 464225 467225
      469222 474219 480217 484217 486215
 2.00 481242 481239 480238 480236 479235 478233 478232 476231
      475231 474232 472233 472234 471236 471238 472239 473241
      474242 475242 476243 478243 480243 481242
 2.00 467237 466234 466233 464233 463233 462236 463237 465238
      467237
 2.00 460238 459233 454233 450233 446234 443235 439237 435237
      433240 437240 440241 443242 448241 452241 456240 460238
      460238
 2.00 453176 452176 451173 450173 451175 451176 452176 453176
 2.00 429243 429240 426238 423236 421236 418235 415234 413234
      411236 408239 411241 415243 418244 422245 425245 427245
      429243
 3.00 479238 479237 478236 477234 476233 474234 474235 473237
      474238 475240 477240 478240 479238
 3.00 481213 481211 479209 477209 477210 476210 474212 472214
      473216 475216 477215 478215 480214 481213
 3.00 473216 472214 470215 468214 468215 466215 465216 466219
      467220 468220 469219 471218 471217 473216
 3.00 463223 462218 458217 454216 450217 445217 441217 438220
      439223 444225 449224 452222 455221 458224 463223
 3.00 458237 457234 455234 453234 452235 451235 450235 448235
      446236 446237 444236 443237 444239 446239 447239 449239
      451239 453238 454238 456238 458237
 3.00 433225 433222 432222 431221 430221 429221 427221 425221
      424222 425224 427225 428225 430225 432225 433225
 3.00 427242 426240 424239 423238 421237 419237 418236 416236
      415236 414237 413238 414239 415240 417241 419242 420243
      422243 424243 426243 427242
 4.00 470218 470217 468216 467217 468218 469218 470218
 4.00 451220 450219 449219 447218 446218 445219 443219 442219
      440219 441222 443222 444223 446223 448223 449222 450221
      451220
 4.00 429223 427223 426223 427223 429223 429223
 4.00 423241 422240 421239 419239 417238 416239 417240 419240
      420241 422241 423241
 5.00 448221 447220 445220 443220 445222 446222 448221