Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 160727
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
227 AM EST TUE JAN 16 2018


PRELIM DAY 1 QPF DISCUSSION
VALID JAN 16/1200 UTC THRU JAN 17/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

...SOUTHERN AND EASTERN U.S...

THE ARRIVAL OF ANOTHER LARGE ARCTIC AIR MASS INTO THE SOUTHERN AND
EASTERN U.S...WILL YIELD A BROAD SWATH OF LIGHT
PRECIPITATION...TRANSITIONING FROM ICE TO SNOW IN SOME SOUTHERN
LOCATIONS...AND FALLING PRIMARILY AS SNOW FARTHER NORTH AND EAST.
THE DISTANCE LAG BETWEEN THE MID-UPPER LEVEL TROUGHS AND THE
ARCTIC FRONT WILL FAVOR PREDOMINATELY ANAFRONTAL
PRECIPITATION...AND WHILE OVERALL LIGHT GIVEN THE ABSENCE OF
SUBTROPICAL CONTRIBUTION (NEGLIGIBLE PW AND LOW-MID LAYER MOISTURE
FLUX ANOMALIES)...THIS EVENT WILL CREATE WINTER WEATHER IMPACTS.
PLEASE REFER TO THE LATEST QPFHSD.

DESPITE THE DEEP-LAYER MOISTURE DEFICIENCIES, SHARPENING
RIGHT-ENTRANCE REGION UPPER LEVEL FORCING (BROAD AXIS OF UPPER
DIVERGENCE AND LOW-MID LEVEL FRONTOGENESIS) AHEAD OF THE PIVOTING
UPPER TROUGH WILL SQUEEZE ON AVERAGE UP TO A TENTH OF AN INCH OF
LIQUID EQUIVALENT QPF ACROSS SOUTH AND EAST TX INTO THE LOWER MS
AND TN VALLEYS -- WITH LOCALLY HIGHER AMOUNTS FROM THE UPPER TX
COAST NORTHEAST INTO SOUTHWEST AND CENTRAL LA WITH A LITTLE MORE
LOW-LEVEL MOISTURE TRANSPORT/FLUX CONVERGENCE TO WORK WITH EARLY
IN THE PERIOD PER THE GFS/ECMWF/UKMET AND HIGH-RES GUIDANCE
CONSENSUS. ELSEWHERE FARTHER NORTH, OROGRAPHIC ENHANCEMENT VIA THE
SOUTHWESTERLY LOW-LEVEL FLOW ALONG WITH THE AFOREMENTIONED UPTICK
IN LOW-LAYER FRONTOGENESIS WILL LEAD TO 0.20+ INCH AMOUNTS ACROSS
THE WESTERN SLOPES OF THE SOUTHERN-CENTRAL APPALACHIANS, DEPICTED
BY SOME OF THE HIGHER-RES MODELS (INCLUDING THE 00Z HREF MEAN)
ALONG WITH THE 00Z GFS.

MEANWHILE, THE LARGEST AREA OF HEAVIER QPF -- AVERAGING 0.25-0.50"
-- IS NOTED ACROSS EASTERN PA/NY INTO MUCH OF SOUTHERN AND CENTRAL
NEW ENGLAND, RESULTING FROM THE DEVELOPING INVERTED LOW-LEVEL
COASTAL TROUGH AND AMPLIFYING WARM CONVEYOR BELT (BECOMING MORE
S-N ORIENTED) AS THE UPPER TROUGH PIVOTS EASTWARD TOWARD THE
ATLANTIC SEABOARD. AGAIN, MOISTURE ANOMALIES (PW AND LOW-MID LAYER
TRANSPORT/FLUX) ARE NEGLIGIBLE, HOWEVER PER THE MODELS WE DO SEE
AN EXPANSION OF THE 0.50" PWs ACROSS SOUTHERN NEW ENGLAND TUE
NIGHT. THE IMPROVED DEEP-LAYER MOIST ISENTROPIC LIFT LATE IN THE
PERIOD WILL EXTEND THE STEADIER PCPN RATES (0.25+/6 HOURS) FROM
THE GULF STREAM INTO SOUTHERN NEW ENGLAND LATE TUE NIGHT (06-12Z
WED). IN TERMS OF THE 00Z MODELS, THE ECMWF TRENDED CLOSER TO THE
GFS SOLUTION, AND AS SUCH A BLEND OF BOTH SOLUTIONS, ALONG WITH
THE PREVIOUS FORECAST AND A BLEND OF THE 00Z HREF MEAN AND 04Z
NBM, WERE USED TO INITIALIZE THE WPC QPF.

HURLEY

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

24HR QP VT 17/12Z
 0.01 493336 491336 490336 488336 486336 485336 484336 483336
      481335 479336
 0.01 521268 520258 518249 516240 514232 511223 509220 509216
      507206 509203 512205 518210 520215 523217 525220 527224
      530225 535220 537213 541201 538199 536196 534193 535188
      533182 531178 529174 525171 521165 519162 516160 509154
      503147 476131 474136 480143 484145 486149 487153 484155
      470148 462145 457145 454146 438150 429149 425148 421145
      414143 407142 402143 401137 401131 405128 406123 410120
      415120 418119 420119 421114 417113 413115 406114 400117
      394116 391113 384108 382106 379106 376116 375125 378133
      382134 385137 389143 385147 384151 382154 382159 387160
      390162 390165 389170 391174 393176 394180 397184 395191
      391192 386191 379189 375186 372187 371190 372193 375198
      376203 375209 373213 368217 366223 365227 362230 365232
      368233 371231 379229 387229 395231 401231 405232 410232
      412230 418227 421225 424224 428224 431226 442230 440234
      437235 430237 415239 416243 418246 424249 427251 426253
      422253 418254 416256 414262 412265 409273 406277 403280
      397283 392286 390288 389292 393298 396304
 0.01 553143 549137 543130 539127 536126 531125 528121 518119
      515126 517137 521146 524150 527151 534147 539148 541149
      543152 549159 550159
 0.01 537210 537207 536204 535201 534203 534206 534208 535209
      535212 537210
 0.01 543820 543812 542807 540789 538782 537775 535768 533765
      530763 525764 520766 517769 510776 504782 492799 481814
      478818 475822 470831 466851 464861 463865 460866 457869
      451877 456881 461882 464885 458895 458901 462903 465908
      467905 470896 473892 474886 478877 476872 471870 469867
      467864 468861 469855 470851 472853 474858 478860 483859
      487861 502870 502855 503842 506838 510836 516835 520837
      529841 532843 535843 540839 543834 543820
 0.01 466707 459694 460679 461671 460666 457659 455655 450656
      447655 444657 430670 424674 418680 414686 408690 394697
      338728 322736 318737 314740 307745 296754 288765 288769
      290772 289776 290779 293780 297779 303777 313775 319774
      322772 329769 335764 340759 350756 356757 365756 372753
      382751 385749 388750 384760 379765 373770 364778 357784
      352790 342802 335817 325829 320834 317839 312845 310848
      309854 308857 304859 301860 296861 290862 288860 288856
      283849 281846 277844 263849 260854 264860 265864 265870
      263876 261884 263893 263917 262921 261923 257930 250941
      241943 236949 232956 232963 235970 236979 238986 241992
      250004 254010 261017 265021 268023 272024 281024 285022
      305997 306993 307987 310978 314971 317963 321956 323951
      327944 332937 339924 345912 361883 370867 373860 378853
      384839 392826 401815 410805 416800 421794 423791 426787
      433788 436787 438789 437793 434804 432807 428809 423810
      421812 422819 420823 420827 423831 425831 426834 426841
      428844 430846 433847 436846 443834 450829 453828 453825
      452801 453775 456757 459740 463720 465713 466707
 0.01 452860 450855 446855 436861 429861 424860 417859 412859
      405859 403860 403864 407867 407873 411876 416877 428880
      433881 437881 439879 442875 445870 450865 452860
 0.01 430795 430793 430790 428791 426793 427796 427798 429798
      430795 430795
 0.01 369111 370106 368104 367101 365101 363099 360098 356098
      354100 356102 357105 359107 360109 362112 365115 367113
      369111
 0.01 360129 361125 359120 358116 355111 350103 346096 344092
      341089 339089 336093 340100 344107 349114 354122 355127
      358131 360129
 0.01 312790 312786 311783 308782 298788 287792 280793 278790
      280785 284781 286775 284772 279771 275774 268783 263791
      259795 255799 251801 247805 243808 241813 239817 239822
      243818 248815 255808 263802 269801 272800 276801 281802
      284803 283806 293805 304802 309796 312790
 0.25 504313 505306 505300 503289 498279 496275 495273 495270
      499262 500255 504251 506246 507239 506229 503220 499211
      494202 490199 487200 481205 478209 480214 483219 487221
      489225 490232 489237 482237 479233 477231 474231 467234
      460234 456235 456239 457241 459245 464248 466252 466256
      463259 460260 451262 448264 446269 443273 440275 425280
      422283 420289 416299 416304 420308 429311 438314 446315
      454313 462317 481325 490327 495327 498326
 0.25 436744 436737 435731 433726 431722 423719 416716 410712
      402709 393709 385710 369717 353726 337733 324743 311754
      306761 307765 310766 318765 325762 340753 345751 349751
      358751 370749 377745 384741 393737 397738 400740 403744
      403750 401758 397766 395771 394776 395782 397785 402784
      405782 411776 424763 431754 434752 436749 436744
 0.25 402214 402213 401211 400210 399209 398208 397207 395207
      394207 394209 395211 395212 396213 397215 398216 399216
      401216 401215 402214
 0.25 420870 419867 417866 416867 415868 416870 417870 419870
      420870
 0.25 387808 388802 385803 378808 371815 366820 364825 362829
      359835 364835 366835 366838 369837 373833 376826 382818
      387811 387808
 0.25 293883 294879 293876 291872 289868 284867 280869 277873
      277877 275882 273886 273889 274892 278893 282892 287889
      291887 292884 293883
 0.25 276952 274947 270943 266945 261949 256952 252955 250962
      250966 252970 257970 263968 268967 272964 275958 276952
 0.25 252982 252981 250980 248982 249984 250984 251984 252982
 0.50 498310 499303 499293 498291 495290 492295 488301 485305
      481311 480316 483322 487324 492322 496317 498310
 0.50 501240 502236 502231 501227 500225 499222 496220 495221
      493225 493230 493233 494236 496239 499241 501240
 0.50 495257 495252 494249 493247 490244 488243 486243 484245
      484249 485252 486256 488258 491260 493259 495257
 0.50 483299 486284 487277 487274 485272 479277 476279 473275
      470272 465271 461273 459277 457281 458287 459297 461302
      464305 468305 471304 480303 483299
 0.50 478241 477238 476237 475237 474239 475241 476242 478241
 0.50 383722 381719 376719 370721 359727 354731 351731 348733
      344735 337738 325746 320751 318754 319757 330749 337745
      343744 348747 352749 356749 365747 368745 371743 373740
      376738 379736 380732 381726 383722
 0.50 288885 288883 287881 288879 287877 285877 284879 283880
      281881 280882 279883 278885 277886 277888 278889 280889
      282888 283888 285887 287886 288885

$$





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