Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 230658
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
258 AM EDT SUN APR 23 2017


PRELIM DAY 1 QPF DISCUSSION
VALID APR 23/1200 UTC THRU APR 24/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1...

...S-CENTRAL APPALACHIANS/SERN US AND MID ATLANTIC...

THE POSITIVELY-TILTED UPPER TROUGH WILL CONTINUE TO DEEPEN AS IT
PIVOTS SOUTHEAST DURING DAY 1...WITH DECENT MODEL CLUSTERING OF AN
EVENTUAL CLOSED MID-UPPER LOW GRADUALLY TRAVERSING THE
SOUTHEASTERN STATES. THIS ALONG WITH THE OVERALL NEGATIVE TILT TO
THE TROUGH WILL GENERATE STRONG...FOCUSED UPPER DIFFLUENCE E-NE OF
THE UPPER LOW...WITH THE UPPER DIVERGENCE GETTING A BOOST FROM THE
RIGHT ENTRANCE REGION OF THE UPPER JET STREAK OVER THE NORTHERN
MID ATLANTIC REGION. THE EVOLVING SYNOPTIC PATTERN...WITH THE DUAL
NORTHERN AND (ESPECIALLY) SOUTHERN STREAM COMPONENTS...WILL FAVOR
A RATHER BROAD SWATH OF HEAVY RAINFALL ACROSS EASTERN PORTIONS OF
THE LOWER OH VALLEY AND TN VALLEY...ALONG WITH THE
CENTRAL-SOUTHERN APPALACHIANS...ADJACENT PIEDMONT...AND MUCH OF
THE SOUTHEAST. WPCQPF WAS INITIALIZED FROM CONTINUITY AND A
NON-NAM/NON-CMC BLEND (PER THE PMDHMD)...LED BY THE ECMWF AND
(ESPECIALLY FOR TIMING) THE WRF-ARW/NMMB.

...KEYS/SOUTH FLORIDA...

SLOW MOVING WEAK UPPER LOW WEST OF THE FL STRAITS WILL ALLOW FOR A
PERSISTENT AREA OF UPPER LEVEL DIFFLUENCE ACROSS SOUTH FL WILL
MAKE FOR A RATHER NARROW CORRIDOR OF HEAVY RAINFALL FOCUSED OVER
THE KEYS AND THE FAR SOUTHERN PORTION OF THE FL PENINSULA...AND IN
PARTICULAR THE WESTERN KEYS CLOSER TO THE LOW-MID LEVEL
CIRCULATION AND THUS MOST CONVERGENT LOW-LEVEL MOIST INFLOW.
MUCAPES OF 1000-1500 J/KG COUPLED WITH PWATS NEAR 2 INCHES (WHICH
IS ABOUT 3 STANDARD DEVIATIONS ABOVE NORMAL FOR LATE APRIL) WILL
PROVIDE A RICH THERMODYNAMIC PROFILE THAT WILL COINCIDE WITH THE
FAVORABLE DYNAMICAL FORCING IN PRODUCING HIGHLY EFFICIENT RAINFALL
RATES. WPCQPF...USING A MULTI-MODEL BLEND WHICH INCLUDED HIGH-RES
GUIDANCE/MEANS...AND LEANING ON THE 12 UTC ARW AND WPC CONTINUITY
INDICATED POTENTIAL FOR A MAX OF 2-5+" OVER THE WRN KEYS. THIS IS
ALSO WHERE THE LATEST SSEO 40 KM NEIGHBORHOOD PROBABILITIES SHOW A
>30% CHANCE OF 3 HOUR QPF EXCEEDING THE FFG...PARTICULARLY IN THE
AFTERNOON INTO THE EARLY EVENING AND WPC UPGRADED TO A SLIGHT ERO
THREAT AREA.

...NRN PLAINS/UPPER MS VALLEY...

GUIDANCE HAS INCREASINGLY CONVERGED UPON DEVELOPMENT OF A SWATH OF
SNOWY PCPN DOWN ACROSS ND/NRN MN INTO THE UPPER GREAT LAKES DAY1
AND A SEEMINGLY REASONABLE SOUTHWARD TREND FROM PRIOR GUIDANCE WAS
NOTED CONSIDERING UPSTREAM FLOW. THIS OCCURS AS DEEP/AMPLIFIED
MID-UPPER LEVEL TROUGHING SAGS SOUTHWARD FROM CENTRAL CANADA AND
AN ASSOCIATED COLD CANADIAN SURFACE FRONTAL SURGE WORKS INTO THE
REGION. EXPECT A STRIPE OF .25-.5+ LIQUID QPF THIS PD. PLEASE
REFER TO PRODUCTS FROM THE WPC WINTER WEATHER DESK FOR ADDITIONAL
DETAILS.

...NWRN US...

GUIDANCE IS ALSO REASONABLY WELL CLUSTERED WITH APPROACH OF NE/ERN
PACIFIC MID-UPPER LEVEL TROUGH ENERGIES INTO/ACROSS THE NWRN US
THIS PD AND LEAD SURFACE FRONTAL PUSH INTO THE PAC NW COAST.
ASSOCIATED HEIGHT FALLS AND MODEST AVAILABLE MOISTURE SHOULD
COMBINE WITH PRODUCE A SWATH OF MODEST TO TERRAIN ENHANCED PCPN
OVER THE PACIFIC NW...WITH LESSENED POTENTIAL INLAND INTO THE NRN
INTERMOUNTAIN WEST/ROCKIES. PLEASE REFER TO PRODUCTS FROM THE WPC
WINTER WEATHER DESK FOR ADDITIONAL DETAILS.

HURLEY/SCHICHTEL

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

24HR QP VT 24/12Z
 0.01 549159 550152 549147 547137 551119 544097 537075 536068
      537060 538054 539048 534039 532034 530029 520010 515003
      510998 501983 497961 496944 493933 489907 483885 481879
      479876 476869 476862 480841 485817 495781 499771 503760
      509752 513749 519748 523747 527748 530747 533744 535739
      536733 535727 531723 525717 517715 508717 503719 502717
      504715 509709 514704 520697 520692 518689 510686 501685
      497685 492686 489687 487685 487676 487671 486666 483663
      479664 471683 470689 467694 463703 457722 458728 460731
      461735 460740 458749 459756 458761 459776 460783 462781
      467771 470766 473765 472771 470776 467786 466794 466800
      467817 466829 464839 463848 462861 462867 461872 458881
      458891 459904 463931 466959 467971 461977 455985 450991
      450996 452002 454010 456017 456023 457026 455029 454034
      452038 448038 445036 440036 438037 438043 442049 444056
      443063 441067 441074 446077 449082 447088 442088 438088
      435092 430090 428087 422076 419071 417066 417062 413060
      409059 407056 402056 400058 401060 401063 398067 396073
      397078 400079 403077 406080 408090 408097 406104 404108
      402108 400106 398105 395111 387115 385118 384124 386127
      389125 392125 400121 407127 409124 411123 414124 417130
      419136 419143 418151 416156 419161 421159 422162 423166
      425175 425181 426186 421196 417196 413199 409201 407206
      403208 399208 397215 397218 399220 401223 403225 400227
      396228 394234 393241 393246 393256 394269 395279 400284
      407290 414295 417298 422300 430303 441306 449306 458305
      463303 466300 472296 479292 481290 480286 479275 482273
      487273 490275 495275 499274 502276 507284 509286 512287
      516283 519274 520269 519266 519262 518259 517256 515253
      515248 515245 515242 517244 518247 520247 520242 520239
      521236 523232 522228 521224 520221
 0.01 520221 519216 515213 517195 517192 519193 523196 527195
      531193 532187 530182 525171 519164 517159 516153 515141
      510131 505122 501120 495120 496115 498108 501105 505102
      512109 515121 523140 529148 535156 538159 543161 549159
 0.01 516193 515190 514187 512189 512191 510194 508196 504196
      503199 504202 506205 507208 508211 511213 512210 513205
      514200 514195 516193
 0.01 505215 504214 503213 503211 502210 501208 501207 500205
      500204 499201 498201 497199 496200 496202 495205 496207
      497208 498209 499210 500211 501213 501214 502216 503217
      505215
 0.01 484196 485190 484185 480178 473174 469174 466177 463183
      459190 460200 463206 466207 469205 473201 478202 480200
      484196
 0.01 435189 434187 432186 430188 432190 433190 435189
 0.01 441130 441125 439123 434124 430124 428126 425131 423141
      424150 425158 426160 428158 432152 433145 436138 440132
      441130
 0.01 399779 399771 397765 394760 390757 387750 385743 384734
      384726 383717 380709 377705 373701 373697 374690 375676
      365674 361674 358678 350703 346714 344721 342726 338739
      334751 331761 329766 325769 316778 314779 310779 305778
      295774 289771 285768 279761 275757 269756 259753 251749
      245746 240747 228752 220754 222758 224765 226772 228777
      229784 230800 230806 231812 236820 243830 256830 263831
      258835 250843 246847 246854 249859 253861 254868 257871
      261872 264870 267867 270867 268872 270877 272880 270883
      264892 258900 251909 248921 244931 241943 238949 238958
      237974 238990 238994 240994 245999 250001 255000 255992
      254986 254972 254965 255960 263931 268921 273913 280903
      287893 294887 303882 308879 314877 327873 332871 339869
      343874 344879 344883 345890 349893 354892 362891 368884
      374875 378859 381848 384834 389823 391817 394810 397796
      399779
 0.01 293075 293071 290066 294058 294054 291050 282047 275044
      268039 265037 263035 264032 266027 265021 258018 250021
      244026 239031 234039 234051 237058 240062 244063 251067
      259072 267075 276078 286079 290078 293075
 0.25 500232 499224 493216 490213 487213 477211 463214 459215
      454214 446216 439217 432220 428221 425224 427230 427234
      410233 405239 403244 405250 408256 407268 408274 409278
      415285 421289 432293 441296 449296 456294 458289 459286
      457264 458258 460255 470256 473256 477253 482250 486250
      489253 492257 494257 494253 492248 489245 485243 483240
      480231 477227 476223 478220 482221 485223 488223 491223
      492227 494234 498237 500232
 0.25 508149 509146 509144 508142 508141 507140 505139 504140
      503140 502141 502142 501144 501146 502147 503148 504149
      506149 508149 508149
 0.25 508065 509059 508054 505044 504042 500040 494041 490043
      488045 488051 488055 486065 486071 486078 486084 490085
      495082 500076 505070 508065
 0.25 482710 482705 479706 478707 476710 473713 472715 471718
      473722 475723 477722 479719 480716 481713 482710
 0.25 469157 470152 471144 471138 471130 468125 466124 463120
      461111 460106 459101 456099 452100 446106 443107 441108
      441111 446118 450126 451130 450135 446143 442152 442157
      443162 447170 450178 455184 459179 460172 462167 469157
 0.25 391785 390775 388767 385763 382761 378755 373747 372742
      373738 374728 370722 368721 364721 358724 352729 347736
      341751 334764 331770 327775 314784 298791 292795 289796
      285796 283788 283781 282775 280771 275767 269763 262761
      253761 244763 238767 236773 237776 239779 244785 245788
      245792 240799 241807 243815 245817 249817 255815 262819
      269822 288819 297819 305819 307818 309815 304812 299811
      303810 307811 312811 317814 314820 310826 306833 304839
      304844 307846 309848 305855 303859 305862 308863 313863
      329860 338859 344861 348864 350866 351872 351877 352883
      353886 358886 361885 366880 370873 374857 378839 382823
      387806 390795 391785
 0.25 295809 293809 295809 295809
 0.25 273056 272055 270054 268054 267053 265053 263052 261051
      259051 258051 258052 257053 257055 258055 259057 261057
      263058 264059 266059 268059 270059 271058 272058 273056
 0.50 479243 479236 475233 471231 469225 469221 468217 459217
      442219 434223 433225 432228 433232 430236 426237 420236
      415236 412240 414246 418255 422264 422271 424275 428278
      434279 438279 441278 441276 439268 444260 450251 457246
      465244 474244 479243
 0.50 455231 454228 453227 452227 451229 450229 450230 452231
      454231 455231
 0.50 383802 384795 383787 382778 379772 377767 371766 365768
      362771 357779 352782 348780 344776 345770 350761 355753
      361743 366740 369736 369734 368730 367728 364728 357732
      352736 349741 339760 335769 332775 329779 325783 320785
      311790 302794 297798 295800 295803 298807 305807 316809
      320810 323813 317822 313826 310831 308837 308839 312843
      316845 321847 327847 335853 346856 354861 358864 359866
      359870 357875 358879 363878 367874 373850 376838 378825
      381813 383802
 0.50 295813 287812 277813 274811 275807 278805 281800 278791
      277786 278782 278777 276773 270768 263766 253766 246769
      243771 243775 248781 249786 249792 247799 246803 247809
      260815 266819 270819 275818 290816 295813
 1.00 459222 457221 457222 459222 459222
 1.00 378800 378794 376787 374782 370780 365781 362785 359789
      356790 347787 342786 336787 329793 324801 323805 326808
      328812 325816 323820 327824 327828 324831 321835 322839
      332840 339846 347850 350852 357852 362850 365847 370839
      373828 375817 377805 378800
 1.00 273799 272789 270779 265774 259771 255771 252773 253783
      255791 252798 251801 252806 258809 265806 271802 273799
 1.50 375808 375801 374794 371790 367787 364789 361794 357795
      352793 343791 338792 335795 329803 332811 328819 332820
      338820 343819 346819 348821 345826 342828 338827 334829
      330831 328834 337836 343843 347846 351847 355845 359841
      360837 363833 366830 369826 375808
 1.50 270798 269789 267784 263780 258778 256783 258789 259793
      259795 255801 257805 261805 267802 270798
 2.00 371810 372804 370797 368794 364796 359798 356801 351804
      345798 339798 337802 336806 336809 338810 346812 350813
      352815 352817 352821 356822 364823 368820 370816 371810
 2.00 356841 356839 356837 355835 353833 351833 350835 349835
      348838 346840 346842 347843 348843 350844 352844 354843
      355841 356841
 2.00 268798 268794 267790 266788 265785 263783 259784 259786
      261788 262792 262793 261797 259799 258801 259803 262803
      265801 267800 268798
 3.00 363814 364811 362810 360811 360812 361813 361814 362814
      363814

$$





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