Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 250701
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 AM EST SAT FEB 25 2017


PRELIM DAY 1 QPF DISCUSSION
VALID FEB 25/1200 UTC THRU FEB 26/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

...EASTERN U.S...

A MID LATITUDE CYCLONE WAS TRACKING THROUGH THE GREAT LAKES ON ITS
WAY INTO EASTERN CANADA. STRONG MID LEVEL COLD ADVECTION AND
HEIGHT FALLS EXTENDED ALONG THE LENGTH OF THE ASSOCIATED FRONTAL
SYSTEM...OVERLAPPING WITH A MODERATELY MOIST AIR MASS AND
UNSEASONABLY WARM AIR WITH UNUSUALLY STEEP LAPSE RATES FROM THE
OHIO VALLEY TO THE DEEP SOUTH. THE RESULT WAS A BROKEN SQUALL LINE
EARLY SATURDAY MORNING APPROACHING THE APPALACHIANS. THIS BAND OF
PRECIPITATION WILL LIKELY WEAKEN...BUT CONTINUED PROGRESSION OF
THE UPPER TROUGH AND LIFTING OF MOIST MID LEVELS WILL MAINTAIN
SOME RAINFALL INTO THE MID ATLANTIC THIS MORNING. THEN EXPECT
DEEPER...NEAR SURFACE BASED CONVECTION TO BREAK OUT OVER THE MID
ATLANTIC AND NORTHEAST DURING THE DAY AS HEATING OCCURS AND HEIGHT
FALLS CONTINUE TO SPREAD EAST. ON THE BACK SIDE OF THE SYSTEM
WRAPAROUND SNOWS WILL LIFT THROUGH EASTERN WISCONSIN AND NORTHERN
MICHIGAN...WITH SOME LAKE ENHNACEMENT OFF OF LAKE SUPERIOR AND
NORTHERN LAKE MICHIGAN...THOUGH WATER TEMPERATURES ARE ON THE COLD
SIDE.

GLOBAL MODEL QPFS APPEAR LOCKED IN...WITH LITTLE VARIATION. THIS
MAKES FOR AN EASIER TASK TO CONSTRUCT THE QPF FOR THIS
SYSTEM...AND WE WERE ABLE TO MAINTIAN CONTINUITY IN MOST AREAS. WE
DID DRY THINGS OUT A BIT OVER EASTERN OHIO AND WESTERN PA...BASED
ON OBSERVATIONAL AND MODEL TRENDS. THE DEEPER AND MORE ROBUST
CONVECTION SHOULD BREAK OUT FARTHER EAST LATER TODAY. ON FRIDAY
THE NAM CONUS NEST HAD DONE A VERY GOOD JOB OF PREDICTING THE
MESOSCALE DETAILS OF THE OBSERVED CONVECTION...AND TODAY WE AGAIN
INCOROPORATED THE NAM NEST. IT OFFERS GREATER QPF FROM SOUTHERN
VIRGINIA THROUGH EASTERN PA/NY COMPARED TO SOME OTHER HI-RES
GUIDANCE...AND WITH UNUSUALLY STRONG INSTABILITY FOR THE TIME OF
YEAR...COUPLED WITH STRONG SYNOPTIC FORCING...WE TENDED TO LEAN
TOWARD THE HEAVIER AMOUNTS...ALTHOUGH STEADY PROGRESSION OF THE
LARGE SCALE SYSTEM WILL KEEP AREAL AVERAGE AMOUNTS UNDER AN
INCH...WITH AMOUNTS GREATER THAN THAT OCCURRING ON SMALLER SCALES.


...WESTERN U.S...

THE NORTHERN STREAM STORM TRACK WILL TAKE SYSTEMS DOWN THE COAST
OF NORTH AMERICA BEFORE TURNING EAST. ONE SHORTWAVE WILL TURN THE
CORNER INTO SOUTHERN CALIFORNIA LATE SATURDAY WHILE THE NEXT DROPS
INTO THE PACIFIC NORTHWEST. BOTH WILL BE SOMEWHAT MOISTURE
STARVED...REMAINING CUT OFF FROM SUB-TROPICAL MOISTURE. COLD AIR
ALOFT AND STEEP LAPSE RATES WILL SUPPORT A SHOWERY REGIME...AND
THE DEGREE OF ONSHORE FLOW AT VARIOUS LEVELS WILL REMAIN FAIRLY
WEAK. WPC QPF LEANED MOST HEAVILY ON THE ECMWF AND NAM CONUS NEST.
THE GFS WAS ON THE FASTER SIDE OF THE SOLUTION ENVELOPE...BUT THE
GFS QPF DID OFFER MORE DETAIL AND GREATER COVERAGE OF AT LEAST
0.10 INCH AMOUNTS IN SOUTHERN CALIFORNIA...WHICH IS SUPPORTED BY
SOME OF THE HI-RES GUIDANCE AND MAKES SENSE GIVEN THE LARGE SCALE
FORCING.

BURKE

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

24HR QP VT 26/12Z
 0.01 471110 472107 470105 468106 466107 464112 463117 464120
      467124 468129 465132 463131 457130 452134 452136 454139
      456143 453148 450148 447147 444139 443135 440135 436152
      434158 436162 441162 444162 445165 449173 452175 452178
      449184 447188 448190 450193 454191 456187 460185 462181
      461176 458175 455172 454168 455163 458158 460161 464164
      466167 468175 472184 476188 477194 475198 472201 468204
      464204 457211 441218 438219 436223 439225 441231 434236
      431239 429243 423246 422250 425253 433256 441257 462264
      470267 480270 487275 490274 493271 498269 501265 505255
      508244 508234 507228 507222 508214 511210 515208 518205
      521205 523203 527204 528202 531197 532184 530176 525158
      522154 520149 514145 509138 506138 504135 501131 498126
      497123 494122 490119 487120 477121 474118 472118 471114
      471110
 0.01 499687 498676 496665 492658 487650 482645 476641 468640
      459644 454648 448653 442657 437663 432671 428680 420695
      411706 405710 398714 391719 383724 379726 375728 368733
      360743 356750 353757 350765 352778 352787 351791 352797
      352804 349811 342824 337830 331837 326842 319847 309856
      307859 309862 316858 330849 334847 339845 344845 347843
      353837 367833 377827 387822 394820 409821 417822 422820
      425816 432815 436817 442815 449815 452814 455809 461806
      466801 471796 476790 487775 493771 498768 501765 504759
      505750 504737 503731 501726 498722 496719 489716 482712
      485707 488704 495697 498693 499687
 0.01 452124 457113 459110 461109 463106 464103 461099 461096
      461093 461086 457078 458076 459070 459063 458058 458045
      459039 458034 458027 458024 459021 462033 465037 468039
      470038 476047 480062 483074 488083 491094 492099 494102
      498104 501101 502088 501078 499068 498061 497057 494030
      492021 488011 486987 486970 489957 489949 488945 487940
      482932 479924 478922 477917 477910 477885 480882 484880
      489876 496871 502865 506858 508852 508846 506841 503837
      496834 487836 483838 478839 473840 470838 469836 465829
      461826 458826 455829 451831 447836 445844 440849 437851
      432852 425846 423843 420845 416849 415853 415863 417868
      420870 428874 432877 435880 439885 442887 454887 458889
      460891 461895 461898 459905 456914 455920 455928 455951
      455965 454969 453976 453983 454987 456998 456012 453017
      448018 444022 442024 442027 442031 440035 438040 439043
      443044 446048 447055 447060 449065 445069 442072 448080
      449082 449086 448094 441096 435095 430093 426094 429101
      428103 425105 419115 421119 425120 429118 433116 439115
      442119 444122 447123 448122 452124
 0.01 457096 457093 455091 454093 454095 455098 457096
 0.01 443186 443183 441183 441185 441186 443186 443186
 0.01 419252 421241 419237 415235 412233 411228 413214 416212
      420209 421205 420199 415191 411185 410180 404142 401138
      398134 395126 395120 396118 400118 403122 407124 407117
      411109 410099 408096 406098 403103 398104 395106 391110
      385109 382114 376114 372120 369127 372148 368156 367162
      370165 374166 378164 382162 385156 387155 389156 390160
      389168 393174 394187 395191 393195 391197 389194 386191
      381187 378183 374181 371183 376187 378188 378191 376192
      376196 378199 380201 383200 385203 400212 405223 405228
      400227 384220 375214 367210 361204 354198 352193 352190
      354189 357187 355184 351183 348180 346170 341166 338167
      334164 329161 326161 322162 319165 319168 320171 323174
      327177 330181 327191 326195 325201 327221 329230 330242
      331246 334250 336254 341257 346261 353266 363269 372273
      377275 381274 390272 405264 412259 419252
 0.01 412071 411067 408064 408058 406056 397054 391060 382060
      380062 380066 378069 375064 372062 368063 368067 371069
      374073 374078 375083 378085 381086 382090 380101 379103
      381106 389089 392082 394078 394071 398069 397074 399078
      401078 403074 405070 408071 412071
 0.01 329803 327803 324806 320810 317812 314815 310817 307820
      309821 314820 318819 321815 323812 326808 328805 329803
 0.01 278800 305786 311768 306755 297755 272780 268783 256793
      256796 259797 264798 270800 278800
 0.01 290837 288833 286833 279836 274836 268836 261842 258850
      257854 258860 260863 264865 270859 275853 281847 287841
      290837
 0.01 257000 257994 255991 251989 248987 242986 239989 238993
      240996 244999 246002 251003 255002 257000
 0.25 494254 495248 495244 493239 491236 483232 478231 474231
      471233 469235 465235 464234 460235 461240 464243 469248
      476253 482257 485259 489260 491258 493254 494254
 0.25 495220 497216 495215 493217 490217 488216 486212 484212
      482211 480213 480216 482219 485221 488223 489224 491224
      493222 495220
 0.25 488686 487677 484670 476661 471657 465656 453664 449668
      446674 444680 442688 441706 439710 437712 432716 422723
      412730 407742 404749 397750 392743 388744 379746 373750
      369755 366762 367768 365780 362787 361790 363792 372781
      374775 376767 377762 381757 384752 386749 388749 385757
      383765 382772 382775 386776 391776 395780 399783 397790
      395793 402795 407799 409802 412804 418803 422799 426795
      432791 438788 446785 458778 467774 478767 483762 488755
      489748 487740 485735 480731 471725 466721 465718 466714
      469708 474702 481695 485691 488686
 0.25 406246 404243 400240 391235 375229 368224 365222 362218
      353214 350212 346211 342210 340207 336203 334205 334209
      337216 338221 339227 341236 345244 349251 356257 366261
      375260 379260 382263 384265 387263 390261 396257 403251
      406246
 0.25 392799 393796 391796 390796 388796 386796 385797 384798
      383799 382800 381802 381803 382804 383805 385804 387803
      388802 390801 392799 392799
 0.50 477679 475676 472673 469672 465672 458677 454685 452695
      449703 444713 439719 438723 438729 438734 433735 431735
      432731 431728 428726 423727 417731 417736 419738 422741
      420745 414752 409757 403764 401767 402772 412772 414772
      418776 426776 431774 437774 444778 472762 477757 482749
      481742 478738 474735 471735 454737 457730 457722 456715
      457707 460697 463686 464680 466679 472680 475681 477679
 0.50 398250 397245 392241 378236 366231 360229 354225 348225
      346230 347232 350233 352230 354231 356234 356238 357241
      359242 360246 359249 361252 373252 377250 379249 382250
      383256 386258 389257 398250
 0.50 392766 390766 390767 389769 388769 389770 391770 392769
      392767 392766
 0.50 373770 373767 373765 373763 372761 371763 370764 370766
      369768 369769 368770 368773 368774 368775 368776 370776
      371774 372772 373770 373770
 1.00 471748 472746 470744 468743 465744 463745 461748 460751
      459754 458759 461758 463756 464754 468752 469751 471748
 1.00 440750 440748 439747 439745 437744 436744 434745 432746
      432747 431748 429749 428750 428751 426752 425753 426755
      426756 428756 430756 432755 433755 435755 437754 438753
      440750 440750

$$





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