Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 170700
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 AM EST WED JAN 17 2018


PRELIM DAY 1 QPF DISCUSSION
VALID JAN 17/1200 UTC THRU JAN 18/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1 (12Z WEDNESDAY - 12Z THURSDAY)

...EASTERN U.S...

THE VIGOROUS MID-UPPER TROUGH PIVOTING TOWARD THE EASTERN SEABOARD
WILL CONTINUE TO TAKE ON A MORE NEUTRAL-NEGATIVE TILT WED AND WED
NIGHT -- AS THE 00Z MODELS AGAIN SHOW A 500 MB LOW CLOSING OFF
ACROSS THE CENTRAL-SOUTHERN APPALACHIANS INTO THE MID ATLANTIC.
STRONGER UPPER LEVEL DIFLUENCE AND DPVA AHEAD OF THE TROUGH, ALONG
WITH THE SHARPER 700-500 MB DEFORMATION/FRONTOGENESIS TOWARD THE
TROUGH AXIS, WILL FAVOR HEAVIER PCPN TOTALS ACROSS NORTHERN SC
THROUGH CENTRAL NC AND SOUTH-CENTRAL VA AS PER THE 00Z GLOBAL AND
HIGH-RES MODEL CONSENSUS. CHANGES FROM THE PREVIOUS WPCQPF
INCLUDED AN EXPANSION OF THE 0.25" CONTOUR FARTHER WEST TO INCLUDE
CHARLOTTE NC, GREENSBORO NC, AND DANVILLE VA -- LINING UP WELL
WITH WHERE THE 00Z HREF PROBABILITIES OF 0.25" OR MORE QPF BETWEEN
12-18Z EXCEEDS 70 PERCENT.

THE OTHER AREA OF MODERATE QPF (AVERAGING 0.25" OR MORE) IS
FOCUSED ACROSS EASTERN NEW ENGLAND...WITH THIS AREA BENEFITING
FROM AN INITIALLY SW-NE ORIENTED WARM CONVEYOR BELT (WCB) BUCKLING
MORE S-N AS THE WEAK SURFACE LOW TRACKS ACROSS OR JUST EAST OF
CAPE COD. WHILE THE APPROACHING NORTHERN STREAM SHORTWAVE (DIVING
SOUTHEAST FROM EASTERN CANADA) WILL ENHANCE THE UPPER LEVEL
CONFLUENCE AND THEREBY STRENGTHENING THE UPPER JET STREAK AND
DEEP-LAYER FRONTOGENESIS POTENTIAL, THE TIMING OF SUCH FAVORABLE
FORCING WILL LIKELY BE SHORT-LIVED AS IT WILL HELP STEER THE WCB
AND MORE VIGOROUS SOUTHERN UPPER TROUGH OFFSHORE FASTER THAN WHAT
WOULD OTHERWISE BE THE CASE. AS SUCH, THE 00Z MODEL CONSENSUS
INDICATED A DECIDED EASTERLY SHIFT IN THE WESTERN EDGE OF THE
0.25-0.50" AMOUNTS ACROSS EASTERN NEW ENGLAND.

GIVEN THE EXPANSIVE WINTER WEATHER IMPACTS ASSOCIATED WITH THIS
ELONGATED AREA OF PCPN ACROSS THE EASTERN U.S., PLEASE REFER TO
THE LATEST QPFHSD FOR DETAILS REGARDING THE SNOW AND/OR ICING
POTENTIAL.


...PACIFIC NORTHWEST...

A STRONG DEEP LAYER LOW WILL MOVE TO NEAR AND JUST OFF THE PACIFIC
NORTHWEST COAST THROUGH THE DAY WEDNESDAY. MOST OF THE HEAVIER
PRECIPITATION WILL STAY OFFSHORE AND OVER BRITISH COLUMBIA DURING
THE DAY...ALTHOUGH WE WILL SEE SOME WARM FRONTAL PRECIPITATION
DURING WEDNESDAY MORNING OVER WESTERN WA...WITH SOME COLD FRONTAL
PRECIP MOVING INTO WESTERN WA DURING THE AFTERNOON. FOR AMOUNTS
WPC FOLLOWED A MULTI MODEL BLEND INCLUDING THE HIGH RES GUIDANCE.

HURLEY/CHENARD


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

24HR QP VT 18/12Z
 0.01 502317 500319 498319 496321 494322 492324 489325 487325
      485326 481327 479327 477328 474328 472328 469328 465328
      463328 460327 457327
 0.01 542198 539188 535178 532170 526161 522154 515147 509142
      500138 496135 493132 490129 486128 483130 480133 479141
      476144 469147 466149 465155 463169 458175 454178 452180
      451178 452170 452166 448167 446171 441180 441186 442188
      446187 448183 448191 446194 441200 437203 433205 425208
      419211 414212 411213 404218 401221 398222 381227 379231
      378236 377240 379245 380251 379257 377261 379263 382267
      387269 390269 395268 398270 396274 390278 386284 384291
      389302
 0.01 477617 478622 480626 485627 489629 491634 496644 500648
      500654 501657 500660 497664 493674 481678 472686 469689
      466695 464700 465709 460718 454727 448738 445748 442759
      440774 438785 433792 428793 427789 433782 433775 432767
      428764 424761 419760 413760 404756 394759 389767 386774
      385780 382791 378800 373808 370813 366816 358824 350829
      341834 336836 332839 324845 321847 315848 309848 308842
      313832 315827 318823 323815 326811 327804 326796 325789
      320791 317794 314796 310796 288791 283789 281788 281784
      274787 270785 266782 262779 258781 253784 247785 244789
      242793 238793 235789 234783 236779 240775 245772 254768
      259765 265764 276765 282764 287765 289767 289770 285774
      284778 288776 298774 300772 300769 298766 303758 310750
      316743 318739 322735 332728 343715 347710 350706 358700
      366693 371690 373686 387668 400655 420637
 0.01 529237 529234 529232 530229 529226 528223 528221 527220
      526219 525218 523218 522219 523221 524224 524227 525230
      526233 526236 527238 529237
 0.01 530758 529741 527723 526717 525711 520709 515711 511714
      507714 507710 508702 511690 510682 508677 505669 501670
      496680 494691 496696 496699 494699 483705 478714 469716
      468720 470724 473730 476732 478734 477742 472750 470761
      471769 473772 476777 473781 461797 457805 457813 459818
      460826 462829 466829 470829 472830 473842 473845 475848
      479848 481844 484840 487831 490829 492830 495829 498824
      500819 504811 506805 509805 514806 518806 521803 524799
      528775 530758
 0.01 526005 523992 520981 512962 509957 507952 504942 498932
      494924 492922 490921 487924 484934 484942 486944 486948
      486954 487959 491965 494967 498967 502970 504978 506982
      512989 517998 513006 511012 513017 515016 519013 526005
 0.01 453794 454791 454789 452787 450787 449790 449792 451794
      453794 453794
 0.01 283881 283873 279870 275870 270874 268878 266884 267892
      267896 269898 273896 276892 280888 282883 283881
 0.01 231967 235975 237978 242978 246977 252976 259973 265968
      267964 267958 268951 265947 261947 250947 242950 235955
      233958 232962 231963
 0.01 265847 265839 260837 257837 251839 246842 243846 241851
      245854 251857 256857 262854 264850 265847
 0.25 449628 458634 468636 471638 474642 474649 471654 464664
      460676 455685 449694 434713 428716 421717 418714 415710
      414700 412699 409698 403701 399705 392712 385721 373740
      360757 353765 346767 339768 332768 328766 323766 316767
      310766 308763 311758 315754 327737 335730 344723 353717
      362709 373704 379695 386688 393680 400677 406675 414667
      419657 426648 435639 439633 443630
 0.25 525258 520247 517236 514226 510214 505203 501200 496198
      488192 484191 481196 474201 467207 459207 451212 445213
      441214 432217 425222 422225 418225 414224 411225 408228
      400232 396234 393238 395244 398248 402251 405255 409257
      414257 433254 440251 450252 455252 461253 463256 462259
      460265 457271 454273 447280 439283 432288 429293 428299
      432302 437305 447308 457307 475304 483302 491302 500302
      504302 507304
 0.25 529205 528195 525187 521182 518175 515169 511164 506159
      499157 487160 483160 482165 483173 487177 491180 491184
      493187 495187 499180 502180 504182 508188 512192 517193
      520195 522198 525204 528206 529205
 0.25 486230 485228 483229 483230 485231 486230
 0.25 373783 372778 368775 364774 359776 352781 347787 343796
      341805 342810 346813 352812 355810 362804 366798 371790
      373783
 0.25 254966 253964 254962 252960 250959 246959 243960 241961
      239962 238965 239968 243969 246969 248968 250968 252966
      253966 254966
 0.50 522264 512228 505210 498205 494204 490202 487200 484201
      478205 473210 465211 452215 444216 438219 431221 428224
      429228 436233 435236 432238 427235 424232 418230 413230
      410232 408235 404235 400237 398240 401243 406244 413248
      421249 429249 435242 437241 441241 450242 458242 462242
      465244 470251 474260 475269 478278 481285 487291 494295
      499294 510296
 0.50 490232 491229 491227 490227 489225 487224 486224 484223
      483223 481223 480224 480226 480227 481229 481231 482232
      483233 484235 486234 488234 490232 490232
 0.50 465647 464644 461642 456640 450637 444639 437649 433655
      430662 423674 419680 421683 423684 428690 431691 434689
      445683 451678 453671 456663 459658 463652 465647
 0.50 410685 408685 407685 405686 404687 403687 402688 400690
      399692 398693 399693 401694 402695 403694 404694 406692
      408691 409688 409687 410685
 0.50 376719 371715 368714 364714 352722 339730 333735 329740
      321752 317758 315761 317763 325760 329758 333758 339760
      344759 346758 358748 363743 367738 371731 374724 376719
 1.00 517267 516261 515256 512242 505220 503214 499210 489209
      484208 481208 479210 478216 483219 491222 493233 494238
      491238 485238 482237 480231 477227 473228 471234 473241
      481248 483254 484260 485266 487272 492282 495286 500288
      504287 507285 510277 512271 515270 517267
 1.00 466222 466221 464219 463217 461217 460218 459219 458219
      458222 458223 460224 462225 464224 465222 466222
 1.00 448224 449222 448221 447220 445220 444223 446224 448224
      448224
 1.00 427242 426240 426239 425238 423237 421236 420235 418235
      416235 414236 414238 414239 415241 417242 418243 420244
      422245 423245 425244 427242 427242
 1.00 362729 360725 353726 348728 343731 338735 335740 334743
      334747 338747 344748 347749 349747 353743 357739 361734
      362729
 1.50 505281 506276 506272 505263 504253 503249 506248 507244
      507240 505233 501217 498214 495215 493221 494229 496237
      497241 497245 492241 488240 485241 484244 485248 489262
      492270 495277 499282 502283 504282 505281
 1.50 489216 489214 487214 487215 487216 488217 489216
 1.50 480239 480236 479233 478231 478230 476230 475231 474232
      473234 473237 474238 475239 475240 476241 478242 480241
      480240 480239
 1.50 424241 422240 421240 420240 421241 422242 424241 424241
 1.50 353739 354737 354735 353733 352732 350732 348732 347733
      345734 343736 343737 343739 344741 346742 348742 350742
      351741 353740 353739
 2.00 504276 503270 501262 500256 497249 493245 490243 487243
      488252 490258 492264 495270 499275 502277 504276
 2.00 502238 502236 502233 502230 501227 501226 500225 500222
      498219 497218 495220 495223 495225 495228 495229 496231
      496233 497234 498236 499237 499238 501239 502239 502238
 2.00 479238 479236 478233 476232 475235 475237 475238 477239
      479238 479238
 3.00 498260 497258 497255 495253 494252 492253 492256 493257
      493259 494261 495262 495263 497263 497261 498260

$$





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