Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 011807
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
107 PM EST THU DEC 01 2016


PRELIM DAY 1 QPF DISCUSSION
VALID DEC 02/0000 UTC THRU DEC 03/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1


...PACIFIC NORTHWEST AND INTERMOUNTAIN WEST...

PRECIPITATION MAY NOT ENTIRELY SUBSIDE DURING SHORTWAVE RIDGING
OVER WESTERN OREGON AND WASHINGTON...BUT WILL PICK UP AGAIN IN
EARNEST ON FRIDAY AS ROBUST ZONAL FLOW DEVELOPS AND A FRONTAL
SYSTEM ARRIVES. ALTHOUGH THERE IS GOOD LARGE SCALE AGREEMENT...THE
GFS CONTINUES ITS TRICK OF DISPLACING THE HEAVIER AMOUNTS OFFSHORE
AND UPWIND OF THE TERRAIN FORCING. THIS COMMONLY OCCURS IN THE GFS
AND DOES NOT LOOK PHYSICALLY SOUND...AND MAY BE IMPACTING OUR
ENSEMBLE TOOLS. SO WE LEANED TOWARD THE SREF MEAN FOR
QPF...SUPPORTED BY THE GEFS REFORECAST DATA BASED ON ANALOG
EVENTS...WITH SOME SPOTTY TOTALS EXCEEDING 1.5 INCHES IN THE
OLYMPIC RANGE THROUGH FRIDAY EVENING.

DOWNSTREAM...TROUGHING WILL DIG THROUGH THE WESTERN
U.S...EVENTUALLY CLOSING A CYCLONIC CIRCULATION AT LOW LATITUDES
OVER THE SOUTHWEST. THE FRONTAL SURGE AND HEIGHT FALLS
ACCOMPANYING THIS SYSTEM WILL INITIALLY STRUGGLE TO PRODUCE
MEANINGFUL PRECIPITATION EXCEPT AT VERY HIGH ELEVATIONS...AS
PRECIPITABLE WATER VALUES WERE AROUND A QUARTER INCH OR LESS
THROUGHOUT MUCH OF THE WEST. HERE WE USED A BLEND SIMILAR TO THE
ONE WE USED IN THE PACIFIC NORTHWEST...INCORPORATING SOME OF THE
SREF MEAN...BUT USING A MAJORITY WRF-ARW AND THE PREVIOUS WPC
FORECAST...HITTING ONLY THE HIGHEST TERRAIN WITH AMOUNTS GREATER
THAN 0.10 INCHES. COVERAGE OF PRECIPITATION WILL INCREASE LATE DAY
1 AND INTO DAY 2 OVER THE SOUTHERN ROCKIES AND SOUTHERN PLAINS.


...TEXAS...

A STRONG TROUGH WILL START TO TAKE SHAPE OVER THE SOUTHERN /
SOUTHWESTERN U.S...LEADING TO THE BEGINNING FRIDAY OF WHAT WILL
BECOME A MULTI-DAY RAIN EVENT ACROSS NWS SOUTHERN REGION. THROUGH
THE FIRST FEW DAYS...THE POTENTIAL FOR MODERATE AND HEAVY
RAINFALL...PERHAPS FLOODING RAINFALL...IS EXPECTED TO FOCUS OVER
EAST / SOUTHEAST TEXAS...WESTERN / NORTHERN LOUISIANA...AND
PERHAPS ADJACENT ARKANSAS AND MISSISSIPPI. MOST RAIN ON FRIDAY
WILL BE LIGHT...BREAKING OUT IN AN ELEVATED FASHION ACROSS MUCH OF
TEXAS AND SOUTHERN OKLAHOMA...AS JET CIRCULATIONS STRENGTHEN AND
UPPER DIVERGENCE INCREASES HEAD OF THE DEVELOPING CLOSED LOW. SOME
LOCALLY HEAVY RAINFALL IS POSSIBLE...THOUGH...AS EARLY AS FRIDAY
AFTERNOON...NEAR THE TEXAS GULF COAST BETWEEN CORPUS CHRISTI AND
GALVESTON. THE WPC FORECAST FOCUSED ON THIS AREA...GIVEN THE UPPER
DIVERGENCE SIGNATURE IN THE 12Z GFS...AND SUPPORTED BY QPF FROM
THE 00Z WRF-ARW AND 12Z NAM CONUS NEST. WE NOTE THAT THE 12Z
HI-RES MODELS LENT EVEN MORE SUPPORT...WITH A CONSENSUS SIGNAL FOR
SOME CONVECTION PRODUCING HEAVY RAIN RATES AND TRAINING FROM
SOUTHWEST TO NORTHEAST FRIDAY AFTERNOON. WPC QPF STARTED WITH A
40/40/20 BLEND OF THE WRF-ARW / OUR IN-HOUSE ENSEMBLE / 09Z SREF
MEAN.


...GREAT LAKES AND THE NORTHEAST...

RELATIVELY COOL AND HUMID LOW LEVEL AIR...SUPPORTING AN UPPER
TROUGH IN THIS REGION...WILL PROMOTE A REGIME OF RAIN AND SNOW
SHOWERS DOWNWIND OF THE GREAT LAKES AND ALSO IN THE WEST-FACING
UPSLOPE AREAS IN PA/NY AND NEW ENGLAND. THE LACK OF STRONG/DEEP
CAA WILL INHIBIT ANYTHING MORE THAN LIGHT-MODERATE LAKE ENHANCED
SNOW OR RAIN/SNOW SHOWERS...WITH THE 24 HOUR AREAL-AVERAGE LIQUID
EQUIVALENT TOTALS EXPECTED TO RANGE BETWEEN 0.25-0.50" OVER THE
FAVORED SNOWBELTS AS PER A MULTI-MODEL CONSENSUS. HI-RES MODELS
GENERALLY OFFER BETTER DETAIL AND ACCURATE PLACEMENT IN THESE
REGIMES...SO WE LEANED TOWARD THE WRF-ARW AND SOME DOWNSCALED
VERSIONS OF OUR IN-HOUSE ENSEMBLE TOOL. FOR MORE INFORMATION
REGARDING THE SNOWFALL POTENTIAL...PLEASE REFER TO THE LATEST
QPFHSD.


...FLORIDA....

A BOUNDARY SLIPPING THROUGH THE FLORIDA PENINSULA WILL LIKELY
PRODUCE SOME SHALLOW CONVECTION AND RELATIVELY INSIGNIFICANT AREAL
AVERAGE QPF...AS A SUBSIDENCE INVERSION ROBS THE AREA OF
INSTABILITY...AND DEEP LAYER LIFT REMAINS FARTHER NORTH AND EAST.

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

BURKE

24HR QP VT 03/00Z
 0.01 528250 529237 532229 535221 535215 535212 533192 529178
      527172 524167 522165 518163 514163 512166 508167 502164
      495162 491161 490159 486158 483160 482155 480154 478151
      477146 478144 481144 487146 492150 496150 493145 490139
      484133 480131 475126 468124 466121 468118 472119 477118
      484120 486120 488118 489114 490109 487103 487098 486094
      483089 478086 475079 470078 466085 464090 464094 463099
      457099 455097 454093 457086 459081 461069 459061 456056
      452059 450068 447070 443069 437069 436074 441075 446080
      447083 447087 443089 438087 433086 431083 428065 425058
      422053 417050 415052 414054 418054 421062 422076 420083
      416089 410093 407095 405098 404106 399107 394111 390114
      385119 380122 376126 374129 376130 381126 385127 388126
      395118 398118 400121 401125 406126 411122 422117 424115
      426116 427121 425127 427126 430123 433116 440108 445106
      449109 447119 448122 451123 454122 455120 457116 460114
      463117 463123 459130 454132 451141 450142 446143 441139
      438144 438148 442149 448149 450149 452151 453154 453159
      451169 452175 448180 443183 442188 444191 446190 450191
      454191 455188 459183 458178 455172 458163 462158 468161
      469163 472161 475159 478160 481162 479165 479173 480180
      480184 478189 476198 474200 470200 462198 456199 453204
      440229 438244 437254 437258 438263 441269 445274 450278
      452284 451289 452292 454300 458307 463312 472320 485327
      489328 492327 495327 499325
 0.01 484707 492682 489659 484646 477639 474637 471636 467637
      462646 461652 463661 469684 467687 462688 459691 457694
      456699 452702 445707 443710 441714 439716 439720 437725
      431727 428730 431733 435732 438732 439736 436739 429743
      427746 426752 425759 424767 420774 417782 405784 399789
      390793 385800 383804 388804 391801 394799 399798 402795
      408789 412788 414791 413794 414808 414814 416818 419819
      422817 425806 431797 433794 433790 436788 436792 435797
      433809 436817 445834 446840 444844 442848 439851 435854
      432854 431852 427850 422850 418853 416857 416864 417870
      432862 437861 441861 443863 447863 452862 454859 457859
      461869 464881 465886 463891 462898 461903 465904 468903
      472893 478885 479880 477875 474865 470843 463837 460828
      456816 454805 452789 450777 449769 450763 452752 454740
      455736 458734 463731 468730 472729 475726 477715 484707
 0.01 474064 475058 473054 471046 467040 462033 457029 455027
      450027 453032 457038 460045 461050 464053 470056 474064
      474064
 0.01 463011 458005 453998 450993 448988 445978 442969 440969
      440976 443985 446995 446000 448005 454011 460015 463011
 0.01 450095 448093 447094 448096 450095
 0.01 441781 441779 440777 439774 438777 437778 436780 436782
      436783 435785 435787 437789 438787 438786 439784 440783
      441781
 0.01 429187 429185 428185 427186 426187 426189 428187 429187
 0.01 430104 429099 427097 424096 420095 418100 417102 416106
      416111 419114 422114 424112 424110 425108 427105 430104
 0.01 423143 422140 423138 424134 422136 421140 419147 416156
      414160 411167 413169 417163 420159 421150 423143
 0.01 410152 409151 408151 407151 406151 406152 408152 410152
      410152
 0.01 414064 411062 412059 411056 405052 399048 394041 392038
      389038 382042 367041 363046 357051 354053 354055 356058
      361058 367055 376057 378060 374061 371059 368059 365063
      366066 365070 366073 370075 372077 372080 373089 371095
      369097 363101 353110 349112 349117 350121 349126 349130
      351128 354126 359121 378096 382091 383085 384081 389075
      390074 391076 392080 394080 396082 396088 394092 394096
      396095 398092 400083 403080 406079 408077 408074 412068
      414064
 0.01 410063 409062 407062 405063 407065 408065 410063
 0.01 400065 398063 396063 395064 394066 394069 396071 397069
      398067 400065
 0.01 361020 362011 362003 360991 356986 354980 354971 357965
      361954 363947 363945 360945 343957 334964 324968 319966
      316962 313956 311949 308943 305939 301937 298932 296924
      293921 290918 283918 275918 270920 266923 263928 261935
      258939 252947 247957 246963 244968 242974 242978 244980
      249990 255999 258003 262005 263002 262996 259989 257984
      255979 254976 257976 261978 262984 268987 271988 270990
      267996 269000 273004 278007 287012 292014 298015 300014
      303015 307018 316025 325030 330032 337033 351034 355032
      358028 361020
 0.01 315114 314109 310108 306108 302111 299114 297118 295122
      299123 303122 306120 310118 313116 315114
 0.01 301760 300749 299745 296745 292746 290748 285753 274778
      272782 269781 268778 265777 260782 258789 256795 252800
      249805 247802 244800 239805 236810 233815 230822 231828
      230835 232837 234835 238830 243823 244817 246814 248815
      253817 255815 258814 260814 262817 269815 274811 285802
      293792 295785 295777 299767 301760
 0.01 297090 290085 285080 279076 276077 270078 265078 262080
      259083 257087 256092 258094 263095 269096 280097 283095
      287095 293094 295092 297090
 0.25 518276 519271 519266 518259 515246 510235 504225 501220
      498214 494210 488208 481208 477209 468214 465216 462222
      461226 459227 455231 451235 448240 446245 447251 461270
      467280 470286 474290 478293 484296 490297 495296 503291
      510284 518276
 0.25 459714 459711 458709 456708 454708 453708 452708 451709
      449711 448714 449716 450717 451718 452719 454719 455719
      457718 458717 458716 459714
 0.25 443749 443747 441745 437745 435746 434749 433754 433756
      433761 434764 438764 440762 442759 442757 443752 443749
 0.25 427791 427786 424786 421787 419790 419792 418797 418800
      418802 420804 422803 423800 425796 426793 427791
 0.25 337006 336005 336004 335002 334001 333000 331999 329999
      328000 327001 327003 327004 329005 330006 331006 333007
      335007 336006 337006
 0.25 322997 322994 321993 320992 319992 317991 316990 315990
      313989 312989 310989 309990 308991 307992 308994 309996
      310996 311997 313998 315998 317999 319999 320998 322997
 0.25 295960 294954 290949 285950 281947 280939 277934 273933
      268936 265941 263947 259958 259962 261964 265966 269970
      270976 272980 274980 279980 284977 288972 294962 295960
 0.25 473108 473109 473108
 0.50 437758 437757 437758 437758
 0.50 511260 510248 509241 507237 496220 488214 482213 479214
      489229 489233 487235 483235 480233 475231 466234 462235
      460237 455240 453244 454249 457253 464260 470268 472273
      475277 482283 487285 491286 495285 499283 502280 505275
      506267 509264 511260
 0.50 500253 499252 498250 497249 497250 498253 499253 500253
 0.50 439755 438754 437755 439757 439755
 0.50 290962 291956 287956 283958 281960 277964 276967 274970
      273976 277978 281976 285973 286970 289966 290962
 0.50 275952 275947 274943 273941 270940 268942 266945 266947
      265951 264954 264958 265960 268961 271960 272956 273954
      275952
 1.00 500269 500264 497260 493251 488244 480239 477235 474234
      468240 472247 482252 486260 487264 490268 489271 494272
      500269
 1.00 502243 502241 501239 500238 499236 499235 498232 497230
      496228 495228 494228 493230 493233 493234 493235 494237
      495238 496239 497240 498242 499243 500243 502243
 1.00 466239 466237 465236 464236 463238 465240 466239
 1.00 283970 284968 283967 281968 279970 277971 277972 277974
      279975 280974 281973 282972 283971 283970
 1.50 479244 479241 478240 477238 475237 474237 473239 473240
      474242 475242 476244 478245 479244

$$





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