Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 180720
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
219 AM EST WED JAN 18 2017


PRELIM DAY 1 QPF DISCUSSION
VALID JAN 18/1200 UTC THRU JAN 19/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1...

...NORTHEAST...

A SHORTWAVE SHEARING OUT ACROSS THE NORTHEAST ON WEDNESDAY WILL
STILL FOSTER SOME ADDITIONAL PRECIPITATION ACROSS NY AND INTERIOR
NEW ENGLAND BEFORE THE ENERGY DAMPENS OUT. ONE AREA OF LOW
PRESSURE NEAR LAKE ERIE WILL BEGIN TO GRADUALLY DISSIPATE WHILE
SECONDARY LOW PRESSURE JUST SOUTHEAST OF LONG ISLAND ADVANCES EAST
OUT TO SEA BY WEDNESDAY NIGHT AS THE REMNANT VORT ENERGY MOVES
OFFSHORE. EXPECT SOME ADDITIONAL LIGHT SNOW AND SOME POCKETS OF
FREEZING RAIN OVER THE INTERIOR...WITH JUST RAIN CLOSER TO THE
COAST. ADDITIONAL WATER EQUIVALENTS SHOULD BE MAINLY UNDER A 0.25
INCH...WITH THE EXCEPTION OF THE NORTHERN APPALACHIANS WHERE THE
TERRAIN OF NH AND WESTERN ME WILL SEE SLIGHTLY HEAVIER
PRECIPITATION. WPC GENERALLY FOLLOWED A MODEL CONSENSUS FOR THE
QPF.

...EASTERN TEXAS/LOWER MISSISSIPPI VALLEY...

THE TAIL END OF A FRONTAL ZONE STALLED OUT OVER SOUTHEAST TX AND
THE LOWER MS VALLEY WILL BE THE FOCUS FOR NUMEROUS SHOWERS AND
THUNDERSTORMS THIS PERIOD...WITH HEAVY TO POSSIBLY EXCESSIVE
RAINFALL EXPECTED AS A DEEP LAYER POOL MOISTURE AND AT LEAST
MODEST INSTABILITY POOLS ALONG THE FRONT. MEANWHILE...FAVORABLE
RIGHT-ENTRANCE REGION JET DYNAMICS ARE EXPECTED TO BE IN PLACE
OVER THIS REGION DOWNWIND OF A BROAD UPPER TROUGH AND CLOSED LOW
OVER THE SOUTHERN HIGH PLAINS AND THE FOUR CORNERS REGION. BY
LATER WEDNESDAY NIGHT AND EARLY THURSDAY THE UPSTREAM TROUGH WILL
BE ADVANCING EAST AND BECOMING MORE NEUTRALLY TILTED AS IT EJECTS
EAST TOWARD ACROSS THE SOUTHERN PLAINS. THIS WILL ALLOW FOR SOME
STRENGTHENING OF THE JET FORCING/LARGE SCALE ASCENT OVER SOUTHEAST
TX AND INTO SOUTHWEST LA IN VICINITY OF THE FRONT. PWATS ARE
FORECAST TO RISE TO NEAR 1.75 INCHES OVER THIS AREA WITH THE HELP
OF A 30 KT S/SW LOW LEVEL JET ADVANCING IN OFF THE GULF OF MEXICO.
IN ADDITION...THE CIRA-LPW PRODUCT SHOWS A WELL-DEFINED
SUBTROPICAL MOISTURE TAP COMING NORTHEAST ACROSS MEXICO FROM THE
EASTERN PACIFIC OCEAN IN THE 700/300 MB LAYER WHICH WILL BE
FOSTERING WARMER RAIN PROCESSES THAT WILL ENCOURAGE HEAVIER
RAINFALL RATES. THE MEAN LAYER FLOW WILL TEND TO BE NEARLY
PARALLEL THE FRONT...AND WITH THE PERSISTENT LEVEL OF LARGER SCALE
FORCING...LOW LEVEL CONVERGENCE ALONG THE FRONT AND FAVORABLE
THERMODYNAMICS...THERE WILL LIKELY BE AN AXIS OF BACKBUILDING AND
TRAINING CONVECTION. THE NAM/GFS AND ECMWF MAY BE TENDING THE
FOCUS THEIR HEAVIER RAINFALL POTENTIAL A BIT TOO FAR NORTH AWAY
FROM THE BETTER INSTABILITY AXIS...AND AS A RESULT KEPT THE FOCUS
OF THE HEAVIEST RAINS JUST A BIT FARTHER SOUTH OVER FAR EASTERN TX
AND WESTERN LA WHICH IS A BIT CLOSER TO THE HIRES MODEL CONSENSUS.
RAINFALL AMOUNTS OF 3 TO 4 INCHES WITH ISOLATED HEAVIER AMOUNTS
WILL BE POSSIBLE THIS PERIOD ACROSS THIS REGION WITH LESSER
AMOUNTS FARTHER NORTH UP THROUGH THE LOWER MS VALLEY.

...PACIFIC NORTHWEST/CALIFORNIA INTO THE GREAT BASIN/NORTHERN
ROCKIES...

STRONG ATMOSPHERIC RIVER CONDITIONS WILL BE WELL UNDERWAY ACROSS
THE PACIFIC NORTHWEST EARLY WEDNESDAY WITH HEAVY RAIN AND HIGH
ELEVATION SNOW...AND THIS SHOULD GRADUALLY ADVANCE SOUTH DOWN
ACROSS NORTHERN AND CENTRAL CA THROUGH WEDNESDAY NIGHT AND EARLY
THURSDAY AS A COLD FRONT SETTLES SOUTHEAST ACROSS THE REGION. THE
LATEST CIRA-LPW AND AMSU 89 GHZ DATA CONTINUES TO SHOW AN
ORIENTATION OF THIS ATMOSPHERIC RIVER THAT EXTENDS IMPRESSIVELY
WELL SOUTHWEST ALL THE WAY BACK TO THE TROPICAL WESTERN PACIFIC
OCEAN. PWS IN THE 700/500 MB LAYER ARE QUITE HIGH AND WILL BE
AIMED NEARLY ORTHOGONAL INTO ESPECIALLY THE SOUTHWEST OR/NORTHWEST
CA COASTAL RANGES BY LATE WEDNESDAY AND THEN DOWN INTO CENTRAL CA
AND THE CENTRAL/NORTHERN SIERRA-NEVADA THROUGH EARLY THURSDAY.
ENHANCED MOISTURE FLUX AND PW ANOMALIES WILL BE IN PLACE GIVEN THE
STRONG LOW TO MID LEVEL WIND FIELD AND UPSTREAM MOISTURE FEED. IN
FACT...A SOUTHWEST LOW LEVEL JET UPWARDS OF 70 KTS IS FORECAST
ACROSS SOUTHWEST OR AND NORTHWEST CA WHICH WILL FOSTER 850/700 MB
MOISTURE FLUX ANOMALIES OF 4 TO 5 STANDARD DEVIATIONS ABOVE THE
MEAN...AND PW VALUES OF 2 TO 3 STANDARD DEVIATIONS ABOVE THE MEAN.
THE HEAVIEST RAINS WILL BE IN PLACE ACROSS THESE AREAS WHERE AS
MUCH AS 4 TO 8 INCHES OF RAIN IS POSSIBLE. THIS WILL LIKELY CAUSE
CONCERNS FOR RUNOFF PROBLEMS INCLUDING DEBRIS FLOWS AND MUDSLIDES
NEAR ANY BURN SCAR AREAS. THESE AREAS WILL BE SUSCEPTIBLE TO FLASH
FLOODING IN PARTICULAR. SOMEWHAT LESSER AMOUNTS OF 2 TO 4 INCHES
WILL BE EXPECTED DOWN ACROSS THE CENTRAL CA COASTAL RANGES AND
INTO THE FOOTHILLS OF THE NORTHERN/CENTRAL SIERRA-NEVADA WITH
ISOLATED HEAVIER AMOUNTS. RUNOFF PROBLEMS HERE WILL ALSO AGAIN BE
A CONCERN AND ESPECIALLY WITH SUCH WET ANTECEDENT CONDITIONS.
FARTHER SOUTH TOWARD SOUTHERN CA THERE WILL BE AN INCREASE IN
ONSHORE FLOW LATE IN THE PERIOD AND SOME LOCALLY HEAVY RAINS MAY
APPROACH THE COASTAL RANGES HERE BY EARLY THURSDAY. FARTHER
INLAND...THE DEEP FETCH OF MID LEVEL PACIFIC MOISTURE WILL
CONTINUE TO OVERRUN COLDER AIR OVER THE GREAT BASIN WHICH WILL
PROMOTE A LARGE AREA OF WINTRY PRECIPITATION INCLUDING SOME SNOW
BUT ALSO SIGNIFICANT FREEZING RAIN/ICING OVER THE DEEPER INTERIOR
VALLEYS OF WA/OR NEAR AND EAST OF THE CASCADES INCLUDING THE
COLUMBIA RIVER GORGE. SIGNIFICANT ICING WILL BE POSSIBLE ALSO OVER
FAR EASTERN OR AND SOUTHWEST ID AS THE PACIFIC MOISTURE OVERRUNS
THE SHALLOW COLD AIR. HEAVY SNOW IS EXPECTED FOR THE HIGHER
TERRAIN OF THE NORTHERN ROCKIES INCLUDING THE SAWTOOTH AND
BITTERROOTS. PLEASE CONSULT THE LATEST QPFHSD FOR MORE DETAILS ON
THE EXPECTED WINTER WEATHER IMPACTS.

ORRISON

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

24HR QP VT 19/12Z
 0.01 523264 522255 519248 518244 518237 517231 516227 513216
      514214 517214 521214 529215 531211 533209 535200 535194
      534188 526173 520165 513159 502147 492137 477131 465138
      462136 459138 451143 446142 445139 444134 444122 441119
      437119 434122 431124 427126 422126 420129 415128 412126
      407126 394128 388134 385135 381133 377131 373129 365132
      352139 342147 337152 334155 329155 321157 319168 322184
      320191 319202 318207 319211 322219 328225 329230 328235
      327241 328247 332254 335260 343263 350267 357265 366263
      372269 378275 385280 400282 408283 415282 423281 430280
      438279 443278 448279 462282 466284 470287 476292 480295
      483297 492296 497297 500296 506293 512287 518277
 0.01 506675 505668 503665 502660 499655 496652 492650 488647
      484648 479650 475653 471657 464659 454663 450667 447672
      444679 440680 437675 431667 425662 415660 404663 398664
      392664 380667 373670 364675 349687 342693 335701 329709
      328716 327722 323740 320750 318760 319768 320774 323778
      327779 334778 338775 341774 342776 345781 346779 350780
      354780 357777 358772 362768 363762 365758 367753 368747
      370743 372735 374731 378728 383725 387726 395727 400726
      404723 412741 413749 408754 405757 402762 404777 397784
      385796 379803 376807 375811 375814 377817 383816 388818
      391815 394809 399807 403811 407813 410820 415819 419817
      424808 429800 433790 436778 439772 440770 443769 451762
      456757 463750 466750 467753 470758 471767 469773 464785
      462789 463797 467800 470799 471797 476790 492752 501734
      505723 507706 504689 505683 506675
 0.01 391906 389898 388894 385890 382887 379885 372881 366875
      359867 354860 347857 344855 343857 335854 331852 329854
      328859 328863 328868 334868 337870 335873 333877 329884
      324890 311898 308900 305896 304890 304885 305879 305873
      306869 306863 305848 305842 306837 306828 304825 301826
      302838 300848 298853 298858 297862 298865 299880 299886
      298891 294908 282918 276923 271929 259943 254949 250955
      246961 243965 242969 244980 250985 245004 245008 248008
      255013 272009 280005 286998 290000 296000 301996 305994
      309994 316992 321984 323982 326982 328988 330992 339995
      347000 353005 356007 359007 367005 374001 378999 378995
      378989 374987 364983 359981 357978 353971 349965 349960
      352956 359952 364947 366942 367936 375933 380932 383928
      386924 388920 391906
 0.01 354846 354844 354841 352842 352844 350846 352848 354846
      354846
 0.25 531197 530193 528189 523183 517176 514173 509171 504168
      500166 497162 492159 482156 475154 463146 460147 457150
      453154 449151 441145 437137 433135 429138 426141 424146
      424155 421165 417174 416178 417180 419185 422188 427191
      431194 434198 441205 445207 447202 457191 461193 460200
      456207 451210 446211 443213 438212 427209 421203 415205
      407201 397199 392197 389195 374184 364178 360175 356177
      352182 348183 346180 343177 338176 335178 333184 332194
      332208 336227 339245 346250 355250 364251 369254 371257
      375261 381264 393267 400267 408267 417267 426266 435264
      444262 452260 457260 461262 475270 483277 490282 499284
      504284 507282 513272 516256 516246 514235 510226 507216
      504211 502205 501199 503195 510193 515193 519196 525203
      529201 531197
 0.25 485233 486231 485228 485227 484227 482226 481226 482228
      482229 483231 485232 485233 485233
 0.25 466697 465693 464693 460696 456696 452698 450701 445706
      441708 438706 435708 434713 436716 439716 448715 455716
      458714 460711 464705 465700 466697
 0.25 426693 424684 420677 414674 407673 398675 391680 391684
      392690 394693 397695 405696 412696 418698 423699 426693
 0.25 366701 366696 365692 363690 359690 353693 347698 339707
      336712 334720 330733 328740 328745 331748 337749 339752
      343751 349747 353748 357746 360740 361733 363717 365710
      366701 366701
 0.25 368909 368904 368899 365891 361889 357888 354886 352881
      347875 346873 345877 342886 338893 327903 321908 318909
      313909 309908 305909 299914 294920 288925 278935 273940
      268948 265954 261962 259965 261970 263974 262978 263982
      266984 272988 279984 286981 293978 299973 307972 313971
      315967 326958 331953 339948 344944 348938 352930 357923
      364917 366913 368909
 0.50 513258 515252 514247 512238 505219 503215 500211 491206
      489201 487196 488189 489185 494180 497177 497173 495168
      493164 485160 480158 474157 467151 461150 459153 456162
      445152 439146 437143 432142 430147 429151 429158 428165
      435180 439186 444191 447190 451190 459187 466184 470185
      473188 475201 468207 462208 456212 449215 441216 431216
      426218 423221 420221 418217 416213 413210 384193 377188
      369183 365181 360181 356183 356187 361191 364193 366198
      365200 360201 353200 350195 349190 346186 342182 339184
      337190 336196 336202 337209 341217 345224 346233 349237
      353242 364245 369246 373250 378255 384259 394261 411262
      427261 437259 445256 451254 458254 467255 476260 491275
      498279 502280 505277 513258
 0.50 489234 489231 489229 489228 487226 487225 486224 484224
      482224 481224 479225 478225 479226 480228 480229 481231
      482232 483233 484235 486235 488235 489234
 0.50 357716 355715 352717 350719 349722 347724 346727 345730
      344732 345737 347737 349736 351733 353731 354728 355726
      356722 357719 357716
 0.50 357905 358902 356899 351897 348896 345897 342902 336904
      331906 322913 319913 313915 307916 305915 301915 294923
      286932 280940 277945 276952 273957 271963 275967 277972
      284973 291973 301967 311963 314959 321956 328950 333947
      338943 341939 344934 350921 353912 357905
 1.00 509246 509238 508233 506229 503222 500215 488209 479208
      473211 471213 468214 462213 455216 451220 446220 443221
      441224 437225 430226 424229 419227 417225 416221 414216
      411214 407213 405210 399205 391200 379192 375188 368185
      364184 361185 361186 363189 368196 372204 373207 370210
      362209 357207 351203 344190 342190 341193 341198 342207
      347209 351211 354214 356218 361229 362233 365236 370238
      376242 381249 388254 396256 410257 418257 423255 436252
      451248 462245 469245 475247 482252 486259 496273 499274
      501274 503268 503262 502258 498252 493245 490242 485240
      482237 480233 479230 475227 470230 467231 464229 467222
      470219 474220 482220 486221 489224 492233 495240 503246
      506249 509246
 1.00 463178 463176 461175 460175 459175 458176 456177 454179
      455181 455182 457183 459183 459182 460182 462181 462179
      463178
 1.00 452173 451168 449163 447160 444156 441153 438151 436149
      433150 433153 433157 435160 438163 441167 444171 448173
      452173
 1.00 343917 341915 337913 334912 330913 322916 315921 310926
      307928 301926 300923 297922 295924 294931 291937 290941
      289947 290950 294948 294953 292958 289964 293966 296966
      302962 306961 310959 315954 323949 328945 334941 338934
      341925 343917
 1.50 498266 498260 498258 496255 495251 492248 491247 488244
      486243 485243 484246 486249 487252 488254 490258 492261
      494264 495265 498266
 1.50 501238 502235 502230 501225 500220 497217 492216 489212
      486213 486218 490220 492221 492225 493230 495234 497238
      501238
 1.50 482244 482242 481239 480238 480236 479235 479233 478231
      476230 475230 473231 471233 470236 471238 472239 473241
      474242 475242 476243 478244 480244 481244 482244
 1.50 465239 467237 466234 464234 462236 458234 453234 445234
      439235 436236 432235 423232 416227 415220 412217 410216
      397205 371189 367188 368190 372196 383208 391219 377223
      372218 370217 368219 368222 371226 374228 377235 381241
      386246 392249 403252 408253 415253 422252 430250 455243
      461240 465239
 1.50 464221 465219 465216 463215 461215 459216 458216 457217
      456218 455219 455220 455221 457223 458224 458225 460226
      462226 462225 464223 464221
 1.50 443162 443159 442158 441156 439154 438153 437153 436154
      435155 436156 437158 439160 440161 442162 443162
 1.50 366218 365217 364216 363215 362214 360215 359217 361219
      361220 362221 364220 366218
 1.50 337926 337922 335919 330917 324919 319923 310930 299933
      297935 298937 302939 304941 299954 295959 293961 296963
      300960 307958 317950 327943 332938 334930 337926
 2.00 495259 495257 495256 494254 494253 492251 491253 492254
      492256 493258 493259 494259 495259
 2.00 499229 499228 499227 499224 498221 496221 495223 495225
      495228 495230 496231 497231 498232 498231 499229
 2.00 478238 478236 478234 477233 476232 475232 474232 473234
      473236 474238 475239 477240 478238
 2.00 462223 463221 463218 462218 461217 460218 459218 457218
      457219 457221 457222 458223 460224 462224 462223
 2.00 458237 450236 441237 437239 432238 428235 422233 417231
      415229 414226 413221 410217 394205 386203 391211 396219
      396224 392225 388224 383227 382232 383238 386242 390244
      395246 401248 412250 421249 430248 438244 445243 454239
      458237
 2.00 379199 380197 379196 377196 376196 377197 378199 379199
 2.00 332926 330923 324922 317928 312933 307934 307937 304945
      303954 306956 310954 316948 322943 324940 327939 330930
      332926
 3.00 428242 427238 423236 413232 411228 411223 408224 406229
      403231 399229 390229 387230 386233 388237 392240 402243
      411244 421245 425245 428242
 3.00 400216 400213 398212 397213 398213 399215 399216 400216

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