Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 190658
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
157 AM EST THU JAN 19 2017


PRELIM DAY 1 QPF DISCUSSION
VALID JAN 19/1200 UTC THRU JAN 20/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1...

...EASTERN U.S...

A LARGE UPPER TROUGH WILL PIVOT OVER THE PLAINS...BRINGING A
NEGATIVELY TILTED SHORTWAVE UP THROUGH THE LOWER
MISSISSIPPI...TOWARD THE TENNESSEE AND OHIO VALLEYS. AT 06Z
SCATTERED THUNDERSTORMS WERE ONGOING IN CENTRAL MS TO CENTRAL
LA...AND OFFSHORE. WATER VAPOR LOOPS REVEALED A WELL DEFINED
SHORTWAVE TROUGH UPSTREAM OVER MEXICO...WITHIN THE PLUME OF
MID-UPPER LEVEL MOISTURE HAVING A CONNECTION TO THE TROPICAL
EASTERN PACIFIC. THIS CONNECTION SUPPORTS MODEL PRECIPITABLE WATER
VALUES THAT PLUME/POOL TO NEAR 1.75 INCHES. AS THE FORCING ARRIVES
EARLY TODAY...EXPECT RAIN/THUNDERSTORMS TO EXPAND IN COVERAGE AND
BECOME BETTER ORGANIZED. FACTORS SUCH AS TIME OF DAY...TIME OF
YEAR...AND DEEPLY SATURATED VERTICAL PROFILES...IN OTHER WORDS
LITTLE EVAPORATIVE POTENTIAL...ALL ARGUE FOR KEEPING THE HEAVIER
SWATHS OF PRECIPITATION TIED RELATIVELY CLOSELY TO THE SYNOPTIC
FORCING. THUS...FOR PLACEMENT OF THE QPF WE TRENDED TOWARD THE
WRF-NMM AND THE GLOBAL MODEL CONSENSUS...TONING DOWN SOME OF THE
FORWARD PROGRESSION BUT TONING UP THE AMOUNTS. MODEL CONSENSUS
PUSHES 24-HOUR AREAL AVERAGE PRECIPITATION TO BETWEEN 2 AND 3
INCHES IN A FAIRLY BROAD ZONE FROM CENTRAL MISSISSIPPI ACROSS
NORTHERN ALABAMA INTO SOUTHERN TENNESSEE. THIS MATCHES WELL WITH
THE GEFS REFORECAST DATA BASED ON OBSERVED PRECIPITATION FROM
ANALOG EVENTS. JUDGING BY THE PRECIP RATES IN THE HI-RES
MODELS...AND CONSIDERING THE QUALITY OF MOISTURE WITH PW ANOMALIES
PLUS-2.5 TO 3.0...IT APPEARS 3-HOURLY FFG OF 2 TO 2.5 INCHES IS
ACHIEVABLE...AND WE MAY EMBED A SLIGHT RISK OF EXCESSIVE RAINFALL
OVER PARTS OF LA/MS/AL/TN.


...WESTERN U.S...

ONE PROGRESSIVE...FULL LATITUDE TROUGH WILL MOVE THROUGH THE WEST
THURSDAY...WHILE A SECOND AND MORE VIGOROUS ONE APPROACHES THE
COAST EARLY FRIDAY. BROAD AND MODERATE HEIGHT FALLS ACCOMPANYING
THE FIRST WAVE WAS YIELDING WIDESPREAD LIGHT TO MODERATE
PRECIPITATION FROM BORDER TO BORDER THIS MORNING. THE HEAVIEST
PRECIPITATION WILL OCCUR OVER SOUTHERN CALIFORNIA EARLY IN THE
DAY...BEFORE THE CONNECTION TO SUB-TROPICAL MOISTURE PINCHES OFF
AND RELOADS OFFSHORE AHEAD OF THE NEXT WAVE. ASIDE FROM THIS
STREAM AFFECTING CALIFORNIA...THE LEAD WAVE WILL WORK WITH
SEASONABLY MODEST MOISTURE ANOMALIES OF PLUS-1.0 TO 1.5...ALTHOUGH
THIS WILL PROVE SUFFICIENT FOR AREAL AVERAGE PRECIPITATION AMOUNTS
OF 0.25 TO 0.75 INCHES OVER MUCH OF THE HIGH TERRAIN WEST OF THE
CONTINENTAL DIVIDE...INCLUDING DOWN INTO ARIZONA...WHILE SUCH
WIDESPREAD HEIGHT FALLS WILL ALSO ALLOW FOR LOWER ELEVATIONS OF
THE INTERMOUNTAIN WEST TO EXPERIENCE MEANINGFUL PRECIPITATION.

BY FRIDAY MORNING THE LEAD WAVE WILL BE CROSSING THE DIVIDE AND
DRYING OUT IN AN AREAL AVERAGE SENSE...AND THE NEXT FRONTAL SYSTEM
WILL BEGIN TO IMPACT THE WEST COAST...ESPECIALLY SOUTHWEST OREGON
TO AROUND MONTEREY CA. VERY STRONG 12-HOUR HEIGHT FALLS IN THE
LEFT EXIT REGION OF A 170 KNOT JET STREAK WILL LIKELY MEAN SOME
CONVECTIVE ENHANCEMENT TO THE RAINFALL COMING INTO NORTHERN
CALIFORNIA AT THE TIME...WITH POTENTIAL FOR RAPID RUNOFF OR SOME
FLOODING CONCERNS ALONG THE COAST. FOR QPF WPC LEANED ON OUR
IN-HOUSE POST-PROCESSED ENSEMBLE TOOL...USING THE WETTER...NON
BIAS-CORRECTED VERSION...WHICH WAS SPATIALLY SIMILAR TO THE
WRF-ARW.

BURKE

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

24HR QP VT 20/12Z
 0.01 522264 520249 516237 511226 506216 504211 503206 505202
      510203 516213 520217 525218 528219 530217 534211 536205
      538202 535191 531180 526169 523165 520164 518161 514160
      509156 504150 501144 498143 495140 490139 486135 482132
      476131 474129 469132 465133 465124 467117 469110 471096
      468085 468076 466070 462065 458062 454059 449057 446055
      444057 440057 430058 417057 414055 411056 405055 397050
      384049 372048 368051 363052 358055 354057 350055 345054
      342057 340062 339068 335071 329072 325074 321080 318085
      313094 305102 303114 303128 303133 306138 313135 322133
      324143 326145 333145 336146 338148 339151 337154 327150
      322151 316150 310149 306151 300157 299169 305179 312181
      316185 321194 323198 327201 328211 328224 330236 336244
      351261 359269 364271 369273 391280 414290 436289 445287
      454284 463282 471280 480279 484279 489281 501287 511293
 0.01 481690 479678 475672 473668 472662 470651 469646 467641
      463635 460634 457635 451639 448646 446653 443662 443666
      440670 436676 434679 435683 439690 444693 448692 450689
      458687 461689 466688 471691 477697 480696 480693 481690
 0.01 475197 475193 473191 470188 467187 464184 460186 457189
      452195 450197 446196 445192 444189 442190 436188 431193
      426191 425189 425184 429182 432181 431176 427173 425174
      421178 420185 420195 427201 431207 439213 446213 459205
      466204 470203 472200 475197
 0.01 478150 479147 479145 478143 477142 475142 473142 471143
      470145 471148 472150 474149 474148 474149 476150 477151
      478150
 0.01 463173 463171 462168 460166 459165 457167 457169 457172
      458174 459175 461175 463173
 0.01 455712 454710 454708 452708 451711 449711 449714 448717
      448719 450719 451716 452716 453713 455713 455712
 0.01 462918 462908 461902 460894 458889 454879 451869 448861
      443853 438844 434835 422818 416811 411804 406796 402788
      395782 392782 388780 376783 371785 366786 347792 342799
      337805 332811 328815 323816 311815 302819 296824 289830
      284836 281838 279842 275851 273861 270872 269877 268882
      265891 261899 258922 253937 247946 246951 246957 246971
      246977 248980 253984 261986 272986 277985 282985 288983
      291980 298975 304968 310962 322949 327944 332939 339930
      346924 353919 361915 366916 369918 375923 381930 381933
      378933 375936 360947 359949 359953 361956 370956 377952
      380949 383944 386936 389936 391938 398938 402936 408937
      412940 422940 430939 436943 445942 457930 460927 461923
      462918
 0.01 438182 438180 438177 437175 436177 435179 435181 436184
      438182
 0.01 440173 439172 438172 439175 440173
 0.01 439762 439760 439757 439755 439753 438750 436750 435751
      434751 433754 433756 432758 432759 432761 432764 432766
      433768 433769 435769 435768 436766 436765 438763 439763
      439762
 0.01 428084 427080 425077 422077 420079 416080 414081 413083
      411087 412092 413094 415097 417099 420100 422095 422091
      424089 426087 428084
 0.01 402195 403191 402188 400185 398183 395184 391184 388181
      383181 382185 384189 389192 392193 397196 400197 402195
 0.01 334058 334057 332055 330055 328057 327057 326057 327057
      328058 330058 332058 334058 334058
 0.25 530205 530194 527186 524184 521183 518183 517180 515176
      512175 507174 503173 505176 508183 514188 517195 522201
      528205 530205
 0.25 383136 383135 382135 383136 383136
 0.25 487233 488231 487228 485227 484226 482226 480225 479225
      477225 475224 474224 475225 477225 479226 479228 480229
      481231 481232 483234 484235 485235 486234 487233
 0.25 454088 454087 454088 454088
 0.25 457086 456085 454086 456087 457086
 0.25 438899 436889 436883 436877 437868 435861 427849 421839
      416831 412826 406822 401820 395819 388818 384816 382811
      380809 376810 373813 370814 367813 361815 355819 350820
      345825 335835 331840 328842 324843 318845 314841 309837
      306837 303840 294845 288851 287859 283873 277883 272896
      268912 267916 268919 271926 274930 271935 267939 265947
      263950 263954 267958 276960 284959 286960 288964 289967
      291964 297956 303950 308945 318937 326930 336921 346911
      352907 357905 365903 370900 376896 381895 388897 394901
      399904 405908 429915 433912 436907 438899
 0.25 428127 429121 426118 423116 419115 411113 403110 399108
      395106 393102 394098 392096 389096 387100 389105 389108
      387111 380115 374116 370117 367113 367108 365104 359099
      355097 352102 353106 350108 345103 343096 339089 335088
      332089 328096 319108 320111 322112 325113 330115 332118
      335126 338132 342139 347145 353149 359152 368156 375157
      382158 389158 393157 396154 401150 411138 416137 423136
      427131 428127
 0.25 515267 516259 515255 513246 508231 505223 502218 498212
      491207 486206 482206 476209 472215 464213 458215 454221
      451228 446231 438232 435234 431232 425227 421222 419214
      414208 404205 388196 377189 371184 364182 358182 354182
      350180 346173 345168 343165 336162 328161 319159 316160
      313162 314166 315169 319173 324179 329184 342192 354191
      364202 363205 358205 352207 350211 351215 354221 356227
      354236 355246 359253 363259 369264 384271 399274 414277
      423278 430277 442275 453270 457267 462258 464256 469255
      471255 475258 482260 488265 492270 497275 502277 508277
      513272 515267
 0.25 387093 387090 387086 384082 381080 376078 374078 371082
      371088 375090 378088 380087 383092 387093 387093
 0.25 444118 443117 443118 444118
 0.50 510265 512260 512255 511249 506236 501223 498218 492215
      485213 482213 480216 485221 489224 491232 491240 486243
      484248 485254 489259 493264 498267 505269 509267 510265
 0.50 479243 479241 479238 479236 478233 476231 475231 473232
      472234 470236 470237 470238 471241 471242 473244 474244
      474245 476245 478244 479243
 0.50 464224 464221 464220 463218 462218 461218 459219 458220
      457222 457224 458226 459227 459228 461228 461227 462226
      464224 464224
 0.50 456244 457240 456238 453239 446240 441242 434244 431244
      428242 422236 418232 416229 416224 415218 413215 405212
      395203 380195 375191 367188 359185 357186 357188 363191
      370196 373203 374207 374213 368217 362218 362223 363228
      365235 368241 372247 375250 376255 378262 384265 392267
      401269 408269 415269 421269 429268 434262 439257 443252
      452250 456244
 0.50 423874 423868 422864 420858 417851 415846 407836 404833
      400830 397829 393830 389834 376837 370838 366838 361836
      359832 359828 358823 356824 351828 343835 336843 329851
      324856 320857 318856 309849 302849 298852 294855 292862
      290869 287874 282885 278895 277902 277908 278911 282911
      288908 289907 291910 290918 286927 277935 274940 272947
      275952 279953 282952 294949 303944 314937 321930 337915
      346906 350903 354900 364896 374890 381887 385886 390888
      395892 405894 410893 413892 415889 419887 420882 423874
 0.50 408128 408124 406121 404120 401118 399117 396116 394118
      392121 391126 392130 393133 395135 397136 401136 403135
      405133 406130 408128
 0.50 381147 376137 376130 373125 369123 365119 361118 356120
      347112 343109 340111 341115 343119 345124 344131 345138
      350141 362142 368144 372147 376148 381147
 0.50 343182 344175 343171 341167 336166 330164 325164 320164
      322169 324172 327174 332177 336180 339182 343182
 0.50 341098 341096 340095 339093 338092 337091 335092 335093
      333095 333097 332099 332101 332102 333103 334104 335104
      336103 337102 338101 339100 340100 341098
 0.50 319877 320875 321872 320870 319869 318870 317871 316873
      314875 314876 313877 314878 316878 318877 319877 319877
 1.00 499235 499232 499230 498229 497226 496226 495226 495228
      495231 496233 497234 498235 499235
 1.00 413250 413248 412247 411247 410247 409248 408248 408249
      410250 412250 413250
 1.00 411230 411228 411226 411223 411222 409222 407222 407224
      407226 407227 408229 408230 410231 411230
 1.00 402247 403242 404238 402232 398228 390227 384225 378226
      377228 378231 382235 387239 392242 396246 402247
 1.00 400216 401213 400212 398211 398210 397209 396207 395207
      394206 392206 391206 390208 391211 393213 394214 396216
      398216 399216 400216
 1.00 386856 360849 351846 345843 342845 340850 338856 335865
      331872 328880 323885 314896 309903 305907 300914 298922
      294928 288932 278943 281946 284945 290943 297939 303935
      314926 326917 333913 338908 349897 355892 360889 380868
      382865 383860 386856
 1.00 309865 308860 306859 302859 299864 297870 294876 292881
      289887 291891 294887 298882 302878 305872 308867 309865
 1.50 368865 367859 363856 356853 352852 347853 344856 342860
      339868 335876 330883 325889 318896 314903 308909 305912
      304916 306920 310921 317917 325912 331907 339902 345897
      356884 362877 366869 368865
 2.00 362865 359860 353859 348859 347861 343866 336878 329889
      321898 317904 316907 317911 321909 326905 331901 337899
      342895 347890 354879 356872 361868 362865

$$





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