Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 270620
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
119 AM EST TUE JAN 27 2015


PRELIM DAY 1 QPF DISCUSSION
VALID JAN 27/1200 UTC THRU JAN 28/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1...

...NORTHEASTERN U.S. BLIZZARD...

THE RAPIDLY OCCLUDING LOW PRESSURE SYSTEM SOUTH OF LONG ISLAND IS
FCST TO CONTINUE TO LIFT NEWD TO A POSITION OFF THE ERN TIP OF
MASSACHUSETTS TUES EVENING THEN CONTINUING TOWARD THE WRN TIP OF
NOVA SCOTIA BY WED MRNG.  SATL IMAGERY CONTINUES TO SHOW DRY SLOT
WRAPPING CYCLONIC AROUND ERN SIDE OF DVLPG LOW AND AS A
RESULT..EXPECT THE MOST EFFICIENT/HEAVIER SNOW FALL AMOUNTS TO
OCCUR DURING THE FIRST HALF OF THE DAY ONE PD AS MID LEVEL DRYING
GRADUALLY GET ENTRAINED INTO THE SYSTEM.  MOST OF THE 00Z MODEL
GUIDANCE CONTINUES TO BE SLIGHTLY FASTER THAN THE 12Z EC OPERATION
RUN AND ARE ALL EAST OF THE EC WITH THE HEAVIER QPF AMOUNTS.  FEEL
THIS TREND IS REASONABLE AS THE EC HAS BEEN CONSISTENTLY TOO FAR
WEST OF THE SUITE OF MODEL GUIDANCE FOR SEVERAL MODEL RUNS.  ITS
OWN ENSEMBLE MEAN SUPPORTS AN EWD/NEWD SHIFT TO HEAVIER QPF
AMOUNTS.  STGLY DIFFLUENT UPR FLOW PATRN EARLY IN THE PD AS A
RESULT OF NEG TILT ORIENTATION OF THE UPR TROF ALONG WITH STG
85H/7H THETAE ADV..SHOULD CONTINUE TO ENSURE STG UVVS IN COMMA
HEAD BAND THRU EARLY TUES AFTN BEFORE SLOW WEAKENING OCCURS.  FOR
QPF AMOUNTS A BLEND OF THE NAM/EC MEAN SEEMED THE BEST COURSE OF
ACTION AS THE GFS APPEARED A LITTLE QUICK TO SHIFT STG HEAVY PCPN
BAND ON THE WEST SIDE OF THE LOW TO THE NE...WHILE THE OPERATIONAL
EC AGAIN APPEARED TO FORCE HEAVIER AMOUNTS TOO FAR WEST.  AS A
RESULT...PLACED HEAVIER AMOUNTS OF 1 TO 1.25 INCH AREAL AVG LIQUID
EQUIVS FROM EXTREME NE MA ACRS SRN AND ERN MAINE. SOME BANDED TYPE
FEATURES LIKELY WITHIN THIS HEAVIER QPF AXIS..BUT CONFIDENCE IN
RESOLVING THE SMALLER MESOSCALE BANDS WAS LOW.  PLEASE REFER TO
THE HEAVY SNOW DISCUSSION...QPFHSD...FOR WINTER WEATHER DETAILS.


...SOUTHWEST/GT BASIN...

A RATHER ORGANIZED NEG TILTED UPR TROF IS FCST TO RAPIDLY WEAKEN
AS IT LIFTS NEWD FROM SRN CA/NRN MEX INTO THE GT BASIN AND
EVENTUALLY AS A WEAK POS TILTED S/WV ACRS WY/UT REGION BY WED
MRNG.  DECENT PLUME OF 1 INCH PWS OF THE EAST SIDE OF THE UPR TROF
IS FCST TO WEAKEN AS EVOLVING SWLY 7H-5H FLOW ALLOWS SOME DRIER
AIR ALOFT TO OVERSPREAD THE SW WITH TIME AS UPR TROF LIFTS NEWD.
THIS SHOULD RESULT IN A GENL WEAKENING AND SOMEWHAT DISORGANIZED
AREA OF SHOWERS TO OCCUR OVER PARTS OF CNTL CA/THE GT BASIN.
GIVEN THE WEAKENING TREND IN MID LEVEL FORCING AND MSTR..PCPN
PATRN IS EXPECTED TO BE RATHER DISORGANIZED AND LIGHT MOST
AREAS..AND AS A RESULT HAVE TAKEN A MULTI-MODEL BLEND APCH TO PCPN
ALONG WITH CONTINUITY.


SULLIVAN

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

24HR QP VT 28/12Z
 0.01 495611 495615 497619 501629 503641 502653 498673 496683
      491692 482706 473723 464736 461741 458742 450748 444752
      437758 429760 420760 415760 412759 402761 397761 394760
      391758 387754 380738 378735 376736 371737 360738 355733
      354727 354721 356713 363706 369702 377698 393689 399683
      403675 409657 415639
 0.01 535201 535192 535186 534182 532179 533174 536166 538162
      538155 538151 537147 534139 531130 530121 531108 532102
      533098 534085 533076 531068 526047 520034 514029 511029
      509031 508036 508042 509052 511063 512067 511074 511096
      511107 511110 512113 512118 513124 515131 517141 517147
      516150 510152 506160 505165 502167 499170 502177 503181
      505180 503189 502201 499206 495207 493204 480206 472206
      465204 462210 456214 451218 443217 441218 439222 442223
      443228 441233 439235 434240 432243 432247 429252 426260
      426264 428263 441259 447256 451251 454249 458249 460248
      465249 470248 478249 486252 491258 501269 505274 509275
      511273 515268 517265 519259 521251 523246 525244 529242
      530240 528237 527230 526220 527214 529211 533207 535201
 0.01 520237 520231 520228 520223 520218 519216 515214 514218
      513221 512223 512226 512228 512234 513237 516239 519239
      520237
 0.01 530029 531007 532996 531984 531973 530970 530964 530955
      529950 528944 525927 523910 521902 517897 512894 509893
      508890 504885 499887 495883 488884 485887 485895 487903
      490909 491925 492934 495942 498947 501953 504959 507967
      512979 515984 518994 523028 524034 527037 530029
 0.01 490234 491229 490227 487225 484224 481223 478223 475225
      477229 479231 481233 484232 486233 488234 490234
 0.01 458103 456087 454080 451075 447070 443067 439067 437068
      434070 434076 435083 434088 431089 427089 425086 423086
      422091 425097 426101 423103 418105 416108 413106 409097
      407099 405102 404104 400106 395107 387106 384106 380108
      375111 364116 356114 351111 344102 342098 340097 337096
      336097 334101 332117 335123 339126 343131 345137 347139
      350137 352137 354140 355142 358149 359152 356154 355160
      356167 357172 356176 353182 349187 345196 344204 348210
      357219 361218 364213 361208 356202 355198 356194 358192
      362192 368194 373199 383207 391209 397208 399208 400204
      397197 399194 402193 408192 414191 418185 425173 443159
      446151 450147 453142 454130 456114 457107 458103
 0.01 415071 415063 413061 409060 404063 402065 400064 395059
      391063 386066 383072 382077 380076 377075 374077 373085
      376091 375100 380099 384094 384089 387087 390085 394085
      396086 403081 406075 409074 413074 415071
 0.01 412784 411781 406782 399784 394789 388793 383800 380806
      378808 378813 385809 390806 397801 402797 409792 412786
      412784
 0.01 376778 374774 371772 367768 364767 361765 358765 358772
      361774 364778 367780 370782 372783 375779 376778
 0.01 365094 366092 364090 364089 362089 360089 359089 358089
      359089 360091 360092 362092 363094 364094 365095 365094
 0.01 356750 355745 353743 350743 347743 346740 344735 340731
      337732 334736 331740 327749 325755 326762 325768 326773
      331775 335773 340770 343766 350760 356750 356750
 0.01 362827 361823 359825 356829 354833 352837 351842 350846
      352848 354846 356841 358837 360832 362828 362827
 0.25 480616 485623 488631 489637 489641 487652 483668 481675
      477684 460709 457715 451721 442733 435736 428739 421740
      412739 405738 400735 395730 391723 390716 391711 393708
      403697 407692 411685 414678 416675 417669 416660 420654
      426650 434646 440642 447637 461628 468626 471623 472619
 0.25 525185 526184 526182 525179 524178 524176 523175 522173
      520172 519171 517172 517173 516174 515177 515179 516182
      517184 519185 519186 520187 522188 523188 525187 525185
      525185
 0.25 500232 499229 498226 498224 496221 495219 494220 493222
      493225 494227 494228 495230 496231 497232 498234 500232
 0.25 447114 448109 447106 446102 444101 441101 439102 437103
      436107 436112 438115 439117 441120 443118 445116 447114
 0.25 422157 422155 422152 420151 419152 420154 418155 418156
      418158 418159 419159 421159 422157
 0.25 395173 395170 394172 395173 395173
 0.25 381195 379192 378190 377189 376189 375186 374184 373184
      372184 370185 369185 368187 369189 370190 371191 372192
      374193 375195 377196 379196 381195
 0.25 340753 340752 338752 336753 335754 334756 333758 333759
      333761 334761 335760 337759 338758 339756 339755 340754
      340753
 0.50 481644 481640 479638 475636 469636 463637 452642 445645
      440648 431657 427669 425674 421680 414689 409700 406705
      401710 400716 400721 403722 406724 414724 419726 423728
      428730 432730 435727 443719 451711 458700 465690 471680
      476667 479655 481644
 1.00 463658 462653 459652 454658 441664 436677 426686 422692
      421699 424705 425709 427712 433713 439711 445707 449702
      455690 462677 463669 463660 463658

$$





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