Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 030742
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
241 AM EST SAT DEC 03 2016


PRELIM DAY 1 QPF DISCUSSION
VALID DEC 03/1200 UTC THRU DEC 04/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1...

...SOUTHERN PLAINS INTO THE LOWER MISSISSIPPI VALLEY...

WIDESPREAD SOAKING RAIN REMAINS ON TARGET DURING THE DAY 1
PERIOD...THE HEAVIEST OF WHICH IS EXPECTED ACROSS EASTERN TX
(INCLUDING THE MIDDLE TO UPPER TX COAST) INTO WEST-NORTHWEST
LA...SOUTHERN AR...AND NORTHWEST MS. A LARGE AND DEEP TROUGH
CONTINUES TO EVOLVE OVER THE SOUTHWESTERN U.S. AND NORTHWEST
MX...WITH A MID LEVEL CIRCULATION NOW NOTED OVER THE NORTHERN SEA
OF CORTEZ PER THE LATEST SATELLITE WV IMAGERY. HEIGHTS WILL NOT BE
TERRIBLY LOW...BUT WITH THE TROUGH DIGGING TO SUCH A LOW
LATITUDE...THE 500 MB HEIGHT ANOMALIES DIP TO A RARELY SEEN MINUS
5.0. UNUSUALLY RICH LOW-LEVEL MOISTURE WORKING UP FROM THE WESTERN
GULF OF MEXICO...COMBINED WITH A SUB-TROPICAL FEED WITHIN
SOUTHWESTERLY FLOW ALOFT...WILL BOOST PRECIPITABLE WATER VALUES TO
WELL ABOVE AVERAGE FOR DECEMBER... WIDESPREAD 1.5 TO 2.5 STANDARD
DEVIATION PW VALUES...WITH THE ABSOLUTE MAGNITUDES OF 1.75-2.00"
ALONG THE TEXAS COAST RANKING NEAR THE RECORD DECEMBER VALUES. AS
WE HAVE ALREADY SEEN EARLY THIS MORNING...MESOSCALE INFLUENCES
WILL LIKELY RESULT IN SEVERAL AREAS OF ENHANCED PRECIPITATION
EMBEDDED WITHIN THE LARGER...MULTI-DAY PRECIPITATION SHIELD.
DESPITE THE INHERENT UNCERTAINTY THERE IS INCREASING MODEL
CONSENSUS AS TO SOME OF THE DETAILS. WPC QPF WAS BASED ON A NEAR
EVEN BLEND OF CONTINUITY (PREVIOUS FORECAST) ALONG WITH THE 00Z
GFS / NSSL-WRF / AND OUR IN-HOUSE ENSEMBLE BIAS-CORRECTED QPF. THE
AMPLIFICATION OF THE WARM CONVEYOR BELT (WCB) WILL LEAD TO
STRENGTHENING AND DEEPENING SOUTHERLY FLOW AND MOISTURE FLUX IN
THE LOWER-MID LAYERS...AS 850-700 MB MOISTURE FLUX ANOMALIES CLIMB
BETWEEN +3 AND +4 STANDARD DEVIATIONS OVER THE WESTERN GULF COAST
REGION.

AS WAS NOTED YESTERDAY...SUCH A HIGHLY-FAVORABLE THERMODYNAMIC
SETUP COUPLED WITH A DYNAMIC COOL-SEASON SYNOPTIC SETUP WILL ALLOW
FOR AN EXPANSIVE AREA OF HEAVY RAINFALL...THOUGH AGAIN EXPECT
ELEVATED CONVECTION TO POTENTIALLY DISRUPT WHAT WILL OTHERWISE BE
OPTIMAL DEEP-LAYER MOIST ISENTROPIC ASCENT WELL NORTH OF THE
SURFACE BOUNDARY. THIS ESPECIALLY NEAR THE GULF COAST WITH THE
HIGHER DEEP-LAYER INSTABILITY (MUCAPES ABOVE 1000 J/KG) AVAILABLE
JUST OFFSHORE. EXCEPT FOR THE NAM (WELL NORTH WITH THE MAX
RAINFALL AXIS)...THE GLOBAL AND HIGH-RES CAM GUIDANCE ARE A BIT
BETTER CLUSTERED IN DEPICTING A MORE CONSOLIDATED AREA OF HEAVY
RAINFALL DURING THE NEW DAY 1 PERIOD...WITH THE AFOREMENTIONED
TROUGH AMPLIFICATION AND STRENGTHENING S-N THETA-E AND MOISTURE
SURGE INDICATIVE OF LESS CONVECTIVE INTERFERENCE FARTHER NORTH
WITH TIME. HOWEVER...STILL LIKE THE IDEA PER THE LATEST CAMS OF
CONFINING THE HIGHER PROBABILITIES OF >5 INCHES FARTHER SOUTH
ALONG GULF COAST...I.E. CLOSER TO THE SURFACE FRONT AND WHERE THE
THERMODYNAMIC PROFILE WILL BE MORE FAVORABLE (NEAR THE AXIS OF
GREATER INSTABILITY AND HIGHER PWS). A BEVY OF HIGH-RES CAMS
INDICATE 24 HOUR TOTALS OF 5-8+ INCHES OVER THIS
REGION...INCLUDING THE NSSL-WRF...WRF-ARW...AND WRF-NNMB. CHANGES
TO THE PREVIOUS WPC QPF WERE MINOR WITH RESPECT TO THE MAGNITUDE
OF FORECAST RAINFALL...WITH A SWATH OF 3-4+ INCH AREAL-AVERAGE
TOTALS STILL ON TARGET ACROSS THE MIDDLE AND UPPER TX
COAST...NORTH TO AROUND LONGVIEW IN EASTERN TX...THEN EASTWARD
INTO NORTHWEST LA. THE EXPANSE OF THE 1+ INCH QPF IS RATHER
IMPRESSIVE...EXTENDING WESTWARD INTO SOUTH-CENTRAL TX AND AS FAR
EAST AS NORTHWEST AL.


...PACIFIC NORTHWEST AND NORTHERN ROCKIES...

STRENGTHENING WESTERLY/ZONAL DEEP LAYER FLOW WILL BRING A MODEST
DEGREE OF DEEP-LAYER MOISTURE FROM THE NORTH PACIFIC INTO THE
PACIFIC NW EASTWARD TO THE NORTHERN ROCKIES. WITHOUT THE BENEFIT
OF A SUBTROPICAL CONNECTION...MOISTURE ANOMALIES WILL BE
MINOR...AS PWS INCREASING TO ~0.75 INCH ALONG THE OR COAST WOULD
EQUATE TO +0.5-1 STANDARD DEVIATIONS ABOVE NORMAL FOR EARLY
DECEMBER. NEVERTHELESS...THE EXPANSIVE W-E ORIENTED WCB ALONG WITH
A PERSISTENT WESTERLY FLOW (OPTIMAL UPSLOPE CONTRIBUTION WITH THE
FLOW MORE OR LESS ORTHOGONAL TO THE TERRAIN) WILL LEAD TO
WIDESPREAD 24 HOUR LIQUID-EQUIVALENT TOTALS BETWEEN 0.5-1.0+ INCH
ACROSS THE WA-NORTHERN OR COASTAL RANGES AND CASCADES...ALONG WITH
THE HIGHEST ELEVATIONS ACROSS NORTHERN ID AND NORTHWEST MT. HIGHER
TOTALS (UP TO 1.5-2.0+") ARE ANTICIPATED OVER THE WESTERN SLOPES
OF THE CASCADES PER THE 00Z HIGH-RES QPFS WHICH WERE WELL
CLUSTERED.

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

HURLEY

24HR QP VT 04/12Z
 0.01 483338 486337 490332 494324 499312 501307 503304 509296
      512287 520269 522254 521249 522242 524226 527222 530220
      535212 537208 539203 540197 541192 539183 531165 529161
      526158 518152 503145 492135 484128 481126 476125 467121
      465119 467116 469113 471110 471105 467102 465103 460102
      458103 456101 454098 450095 444095 436096 432098 430103
      423106 424111 422115 420116 425119 425122 428122 434117
      448124 451123 455120 456119 455114 458112 460114 461120
      461126 454131 452133 450138 436148 435153 437158 441166
      444175 445181 443186 449188 455186 462181 463175 466171
      484177 487180 488186 489190 488193 485196 482198 475201
      468205 465207 460207 454211 446213 439216 433218 425220
      423223 425225 427230 425238 425242 426244 428247 432257
      433267 432279 432285 433290 439305 441313 445322
 0.01 565024 564014 561009 555998 542981 538976 534973 531971
      529970 524966 507957 504956 501954 495954 489954 484957
      481962 479966 479974 480977 480981 483988 478992 474996
      471000 470007 471011 483012 487013 490015 490018 489020
      483024 477024 467028 464030 465035 469040 472046 479054
      484059 486064 487078 492079 493087 495102 497108 501111
      510108 513103 515097 514081 513072 511065 509060 506057
      504054 503048 503041 502033 502027 505027 510025 516026
      527026 530026 532024 535021 537016 540019 543023 551032
      552034 555034 558034 563029 565024
 0.01 491884 492875 491868 484864 481864 479862 474862 471863
      469860 467853 462854 458842 455843 451842 449841 446843
      442848 437847 435845 434847 438859 440864 443865 447864
      452865 455864 460861 466873 468878 466883 466890 468893
      468897 470902 472902 474900 473896 475888 477895 478895
      482890 486887 491884
 0.01 483872 482870 481869 479870 478872 479874 481874 483873
      483872
 0.01 464708 462698 456700 454704 449707 445707 442708 439712
      437719 434724 429727 427731 430733 435733 438738 435743
      429745 424743 420743 419746 418752 420757 418761 417766
      419769 421770 419773 417771 414772 415775 412776 408779
      401787 396789 393791 383796 381802 383805 398794 405793
      409796 412802 413809 412814 415817 418821 420818 423811
      424809 426810 430813 433818 436823 439825 446829 450831
      453826 452820 448817 443807 440805 435804 431801 427798
      425794 426791 429786 434778 434771 435766 438760 441757
      448754 450750 458730 460724 462718 464708
 0.01 477929 472917 460917 450910 446906 442903 434897 426892
      422888 416888 410889 406891 399892 391892 385895 382895
      379887 378884 379880 379865 380860 380853 379836 377831
      376823 371810 369804 365798 362794 359796 352806 344813
      337822 332824 330830 321847 318853 315858 312864 308867
      302869 295872 291874 288877 284880 281883 277888 274888
      271886 267882 263883 262895 263901 266907 273915 277919
      274925 269936 266949 262959 261964 257967 251974 252985
      242989 238993 238997 241008 241016 243020 251025 254028
      258032 260035 263041 263050 261057 261063 263068 266074
      267076 270079 278085 281088 283092 285097 289101 297106
      301110 307111 312109 315107 317104 321101 327100 330099
      334099 338097 342094 344089 346083 347077 352066 358056
      360051 362043 363036 366028 371018 374012 377007 381002
      382000 386000 390002 393000 400992 414977 422966 427956
      431955 435955 441955 448955 453958 463962 468962 472958
      476952 472942 477929
 0.01 454061 453056 449054 448048 446043 445038 441038 441041
      444046 446051 446057 447063 450066 454061 454061
 0.01 449080 450078 449077 449075 448074 447073 446071 445071
      443070 441069 441072 443074 444076 446077 448078 449080
      449080
 0.01 430185 429182 427184 426187 426189 428187 430185 430185
 0.01 429168 429166 429168 429168
 0.01 425700 425698 424696 423694 422693 421692 420691 418690
      416690 415690 413691 413692 413694 413696 414697 415698
      416699 417700 418702 418703 420703 422703 423702 425701
      425700
 0.01 431862 429859 429857 429855 429854 427854 425855 424855
      424858 424860 424862 426862 428864 429864 431862 431862
 0.01 422140 422138 420137 420138 418139 418140 418142 420140
      421140 422140
 0.01 285804 283802 279800 277799 274799 270796 268797 266800
      268804 272806 276807 280808 284806 285804
 0.01 256789 256784 253783 250788 246794 244801 242809 242812
      240817 241821 245819 247817 251810 254804 256797 255792
      256789
 0.25 530205 531200 531194 530188 526177 524171 519166 513165
      508164 503163 498161 491155 485151 479149 478147 480145
      482146 486146 490144 489137 485133 479131 474132 471138
      470140 467141 463142 459145 457150 458153 461158 464161
      471164 478165 483168 487171 496179 502186 507192 511195
      516198 520202 522205 526207 530205
 0.25 516267 517261 516257 514250 511242 509238 506235 505231
      503223 502216 499210 496204 492201 481203 461214 450220
      449222 452225 454228 453233 451234 448237 450252 450260
      451268 455270 457269 461263 464257 469253 473249 478251
      491255 497245 501248 504255 498266 503270 508270 513269
      516267
 0.25 409947 408942 405940 402943 398943 393945 389947 386949
      383952 382954 379953 375952 373949 370940 366932 362883
      360874 358861 355843 354837 352832 349831 347832 344834
      340843 338847 335850 331854 327862 323868 319875 310890
      307889 305886 301886 298889 293894 291897 291902 299908
      290922 284928 278935 274942 271950 269958 268968 266979
      263986 258994 253000 252003 252008 255015 265025 273030
      279036 282043 282049 280053 279058 277059 279066 281074
      287079 296083 299086 304086 311081 315079 318076 328064
      333059 334056 336051 336047 339042 343035 347026 352018
      358002 361994 364992 370984 373981 375983 375988 377990
      380989 385983 394968 403957 409947
 0.50 496226 498221 497218 494212 491209 486206 478208 469212
      461217 457219 455221 462231 461239 465239 467237 466235
      465229 472224 477222 482224 489224 494226 496226
 0.50 483242 484240 484239 483237 482236 481234 479232 478233
      477233 476234 475234 474237 474239 475241 476243 478244
      479245 481244 483242 483242
 0.50 483161 482159 480158 479160 480160 481161 483161
 0.50 485138 484136 482135 481135 479135 478137 479138 480139
      482139 484139 485138
 0.50 472158 472156 470154 469153 467153 466154 466157 467157
      468158 470159 472158 472158
 0.50 357925 358915 357906 355890 354881 353874 350869 349864
      347854 345849 343849 342852 338857 333866 328870 325874
      315898 309907 303916 286931 283935 279939 274949 271963
      271980 268994 269002 271006 282028 287039 291049 294061
      291066 292073 296076 303076 311072 321065 323063 323060
      321058 318058 315057 316050 326045 332034 334028 334021
      333005 333991 335975 343967 347962 349957 353945 357925
 0.50 315018 315016 315013 314013 313013 311013 310013 309013
      307014 305015 304017 304019 305021 305023 306026 307027
      307026 308025 310024 311024 312022 312021 313020 314018
      315018
 1.00 487218 488216 487214 486213 486212 484211 482210 481210
      479210 477210 476211 475212 474214 473216 475217 476218
      478218 480219 481219 482219 483219 485218 487218 487218
 1.00 472218 473216 472216 471216 470216 468215 467217 466219
      467221 469221 470220 471219 472218
 1.00 348921 349910 348899 347889 344884 339879 335878 332881
      326894 310916 306921 301926 292933 286937 281943 278949
      276955 274962 273967 274970 277977 283980 298002 307000
      311995 317983 321976 325970 334960 337954 341947 345934
      347926 348921
 1.50 482216 482215 482214 481212 479212 478213 478215 478216
      480216 482216 482216
 1.50 341917 341908 339901 337895 334894 331895 317912 310922
      303930 285942 281947 278953 275964 277970 280972 284972
      296970 298971 299973 299982 300987 298989 298992 300992
      303986 307982 315975 322966 328956 334945 338934 340924
      341917
 2.00 336926 336918 335912 330911 325911 322912 318915 313922
      307930 301935 292939 285944 281948 279953 278958 278964
      282967 288967 296962 299960 305959 305964 304968 303974
      306975 314971 319964 324956 329947 332939 336926
 3.00 327939 326931 323926 318926 314929 305937 301940 296942
      290945 287949 284954 285958 287958 292956 297954 303952
      308951 311952 311956 311960 312964 319956 323950 325945
      327939
 4.00 308945 307943 307941 306941 305942 304943 304945 305946
      307946 308945

$$





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