Quantitative Precipitation Forecast
Issued by NWS

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764
FXUS04 KWBC 110701
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 AM EST THU FEB 11 2016


PRELIM DAY 1 QPF DISCUSSION
VALID FEB 11/1200 UTC THRU FEB 12/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1...

...COLD TROUGH OVER THE EASTERN U.S....

A SHORTWAVE TROUGH...EMBEDDED WITHIN A LONGWAVE TROUGH OVER THE
ERN U.S....WILL EXIT THE NORTHEAST THIS EVENING AS ANOTHER IMPULSE
APPROACHES FROM THE UPPER GREAT LAKES REGION BY 12Z/12. LAKE
EFFECT SNOW SHOWERS WILL BE COMMON SOUTH AND EAST OF THE LAKES
WITH STEEP LOW LEVEL LAPSE RATES PROMOTING SNOW SHOWERS FARTHER
AWAY FROM THE LAKES ACROSS NEW ENGLAND.

A NARROW BUT ROBUST LAKE EFFECT SNOW BAND EXTENDED WEST-EAST
ACROSS SRN LAKE ONTARIO DURING WED EVENING AND CONTINUES EARLY
THIS MORNING...BUT IS STARTING TO SEE SIGNS OF DISRUPTION AS OF
06Z. A SURFACE TROUGH LOCATED JUST NORTH OF THE REGION IS EXPECTED
TO SWING ACROSS THE NORTHEAST DURING THE DAY TODAY WHICH WILL
SHIFT WINDS TO A NWLY DIRECTION WHICH SHOULD WORK AGAINST THE
MAINTENANCE OF A SINGLE LAKE EFFECT BAND...WITH MORE WIDESPREAD
BUT LESS INTENSE SNOW SHOWERS EXPECTED. SUBSIDENCE BEHIND THE
DEPARTING SHORTWAVE SHOULD HELP TO DIMINISH LAKE EFFECT SHOWERS TO
SOME DEGREE BY 00Z NEAR LAKES ERIE AND ONTARIO...BUT PRIOR TO
THAT...THE FETCH OF WINDS ACROSS LAKE HURON AND ACROSS LAKE ERIE
MAY FAVOR SOME LOCALLY HIGHER TOTALS NEAR NWRN PENNSYLVANIA.
ACROSS THE U.P. OF MICHIGAN AND LOWER MICHIGAN...LOW LEVEL FLOW IS
EXPECTED TO CHANGE FROM NNWLY TO WLY AND BACK TO NNWLY THROUGH
12Z/12 DUE TO THE APPROACH OF A MID-LEVEL CLOSED LOW DROPPING INTO
ONTARIO. WPC QPF FOLLOWED A BLEND OF THE LATEST HI-RES MODEL
GUIDANCE GIVEN GOOD MODEL AGREEMENT WITH FORCING MECHANISMS.

...NRN PLAINS TO OHIO VALLEY...

NORTHWEST FLOW WILL BE IN PLACE ACROSS THE PLAINS...ATOP A STRONG
FRONTAL BOUNDARY CURRENTLY EXTENDING FROM MONTANA INTO NRN
MISSISSIPPI/ALABAMA. AS A WEAK SHORTWAVE CROSSES AN UPPER RIDGE
OVER THE WEST THIS MORNING...THE SHORTWAVE WILL SHEAR AS IT TRACKS
SEWD...BUT WILL BE ENOUGH TO FORCE A SURFACE LOW AND WARM
ADVECTION SNOWFALL IN A STRIPE FROM THE NRN HIGH PLAINS INTO THE
LOWER OHIO VALLEY. PRECIPITATION WILL BE AIDED BY LOW LEVEL
FRONTOGENETIC FORCING...WHICH APPEARS TO BE STRONGEST ACROSS THE
PLAINS...AND WEAKER AS PRECIPITATION REACHES EAST OF THE
MISSISSIPPI RIVER. A BLEND OF THE 00Z GFS/12Z ECMWF WAS WEIGHTED
MOST FOR WPC QPF...BUT BLENDS WITH THE HI-RES GUIDANCE WAS USED AS
WELL GIVEN GOOD MODEL AGREEMENT.

...PACIFIC NORTHWEST...

AN UPPER TROUGH WILL EDGE EASTWARD TOWARD THE WEST COAST WHERE
UPPER RIDGING HAS BEEN PRESENT OVER THE PAST FEW DAYS. THE UPPER
TROUGH WILL BE STRONG ENOUGH TO ALLOW A COLD FRONT TO REACH THE
PACIFIC NORTHWEST BY 12Z/12...WHICH IS FORECAST TO BE ASSOCIATED
WITH PRECIPITABLE WATER ANOMALIES OF +2 TO +3. 850-700 MB FLOW
WILL BE FROM THE SSW AND PEAK IN THE 30-4O KT RANGE AHEAD OF THE
COLD FRONT AND ENHANCED VERTICAL MOTIONS WILL BE ATTRIBUTED TO
DIFFLUENCE ALOFT AHEAD OF THE UPPER TROUGH. THERE WERE SOME MINOR
TIMING DIFFERENCES WITH THE PRECIPITATION SHIELD MAKING
LANDFALL...WITH THE 00Z GFS A BIT FASTER AND 12Z ECMWF TOWARD THE
SLOWER SIDE...BUT GENERALLY THE MODELS SHOWED GOOD AGREEMENT WITH
THE OVERALL SETUP. PRECIPITATION WILL BE HIGHER IN THE
OROGRAPHICALLY FAVORED TERRAIN...MAINLY SW FACING SLOPES. WPC QPF
FOLLOWED A GFS/ECMWF BLEND.

OTTO

GRAPHICS AVAILABLE ON THE WEB AT WWW.WPC.NCEP.NOAA.GOV

24HR QP VT 12/12Z
 0.01 539205 535195 529182 524171 516164 512162 508159 505155
      504150 501146 486133 465094 456097 451093 446092 441094
      440102 442108 445111 449121 443132 445144 448153 450160
      450165 448167 443181 441197 439205 436211 433215 429219
      427221 426225 422229 416236 415239 418241 415243 406250
      402252 400255 399260 399266 400268 403269 409271 411273
      409277 406281 406287 406291 409294 412298 424303 435307
      447312 454314 461316 473319 481317 485315 492317 499324
 0.01 549112 550099 546090 539081 530079 522078 517072 514066
      511064 508057 506052 504047 500040 494030 491027 488022
      477009 470996 460981 450961 433933 429926 424919 421913
      419908 422895 421887 416882 410877 407878 405880 402880
      398878 396872 393864 387856 383852 379852 376855 374860
      374865 375870 377878 381886 379891 381895 381900 383904
      393924 396931 401938 409952 413961 417969 422980 425984
      428986 437999 444014 452032 463050 474063 479069 484073
      490079 493081 497082 509084 512087 515093 501106 501111
      502116 507123 511126 515132 520139 523144 526147 529149
      532147 536142 540135 543130 546122 549112
 0.01 532235 533230 532225 529221 525215 521210 519212 516212
      512210 510212 511220 513226 517232 520236 524240 527244
      529242 530237 532235
 0.01 491664 489664 488665 488668 487671 488670 489670 490668
      490667 491664 491664
 0.01 486679 486676 484677 480682 472690 470692 468690 463685
      461683 462678 464668 463663 464656 471645 470638 467636
      464636 462635 457632 454631 450632 449634 444637 440642
      434646 427648 419650 414656 408664 400671 391676 387681
      384687 380690 378696 371706 365710 361715 359721 357725
      358728 362731 366733 376735 381736 385736 396738 399735
      402734 406731 412720 414714 416713 418714 418719 417722
      419726 418733 423735 428736 431734 436733 442733 448734
      447737 443740 439742 428740 423742 418745 415751 413755
      410756 416759 412765 408763 408770 410774 409780 405783
      400786 394791 389794 382802 382807 385804 392801 397802
      398805 402804 405806 408812 413822 415826 418823 420818
      423812 430820 439825 443829 447831 451831 452835 451840
      449842 446849 442849 441858 436861 433861 430860 428855
      424852 419854 415855 413858 413865 416870 425865 433866
      436866 441868 448866 455865 460865 462873 464885 465901
      467905 469906 470907 472905 476890 478885 481879 483871
      483865 482858 482853 480850 477845 474831 473815 471807
      470800 467784 461773 455763 453760 455757 459756 465754
      469749 470742 468725 467717 465712 466708 469706 473708
      476704 474700 474695 477690 482687 486679
 0.01 459692 458687 456683 452684 449685 448688 446690 443691
      442694 441699 443701 445703 448704 450701 451701 455702
      456700 457695 459692
 0.01 453083 451080 450078 449078 448075 446074 445072 443072
      444075 446075 448077 448078 449080 451083 452085 453083
 0.01 446785 446776 443773 441774 439779 435785 433790 429795
      429800 433806 438801 441798 445793 445788 446785
 0.01 372824 372819 370820 365826 360827 358830 356832 355835
      352842 352850 356852 358850 361852 365852 368844 368841
      369835 371828 372824
 0.01 330779 325768 322766 316767 313770 311775 307784 303789
      302793 304808 304814 308817 313814 315811 321801 326794
      329790 329783 330779
 0.25 522261 512236 504223 497213 494209 486206 481203 477202
      471203 466209 462213 459217 458222 460224 465229 461233
      456234 451235 448236 446241 439251 436255 433266 436279
      440284 448288 453292 459294 464298 470303 482305 487305
      493303 502297 507293 513291
 0.25 482229 483227 482225 482224 481223 479221 478220 476221
      474222 474224 475226 477226 479226 480227 482229 482229
 0.25 471855 472853 471850 470848 470847 468847 468848 467851
      466851 466853 466856 466858 466861 467862 468861 469858
      470856 471855
 0.25 431764 431761 430759 430762 430764 431766 431764
 0.25 423796 421794 420796 420797 420799 421799 422799 423796
 0.50 516272 518267 518262 516253 510242 504229 497218 494214
      490211 486211 479209 474209 471210 469213 467217 469220
      474217 480218 484222 488229 484235 482237 479231 476230
      473230 469235 465237 459239 454243 451248 448253 446260
      446270 447276 453279 459279 463279 467281 473282 477280
      490288 493290 496290 500287 506285 511281 516272
 0.50 468275 466273 465272 463272 461273 463275 464276 466276
      468276 468275
 1.00 502272 503268 503263 502256 500251 501243 499237 497231
      496235 497240 497242 494242 489240 486240 485242 482244
      481242 479236 477233 474233 473236 473239 476244 479249
      480254 485265 488270 492273 498274 502272
 1.50 499263 499261 498258 497254 495251 493248 491246 488245
      486248 486253 486256 487260 489262 492265 495266 498266
      499263
 1.50 478238 477236 477235 476234 475235 475237 475238 477239
      478238
 2.00 496260 495257 495255 494254 494253 492251 491250 489252
      489255 490256 490258 491259 492260 494261 496260

$$





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