Quantitative Precipitation Forecast
Issued by NWS

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430
FXUS04 KWBC 221916
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
216 PM EST THU FEB 22 2018


PRELIM DAY 1 QPF DISCUSSION
VALID FEB 23/0000 UTC THRU FEB 24/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

...NORTHEAST TX---LOWER MS VALLEY---LOWER TN VALLEY---OH
VALLEY---NORTHERN MID ATLANTIC INTO SOUTHERN NEW ENGLAND...

AS THE NEXT IN THE TRAIN OF WAVES MOVES NORTHEASTWARD CONVECTION
IS AGAIN EXPANDING IN COVERAGE OVER PORTIONS OF FAR NORTHEAST TX
INTO SOUTHEAST OK AND SOUTHWEST AR. THE WAVE HAS HELPED STRENGTHEN
THE UPPER JET TO THE NORTH...ENHANCING RIGHT ENTRANCE JET
DYNAMICS...WHILE ALSO STRENGTHENING 850 MB MOISTURE TRANSPORT OVER
THE STALLED OUT LOW LEVEL BOUNDARY. THIS WAVE AND MOISTURE
TRANSPORT MAXIMUM WILL GENERALLY BE PROGRESSIVE OFF TO THE
NORTHEAST. HOWEVER THE STRONG LOW LEVEL FLOW DOES SUPPORT SOME
BACKBUILDING INTO THE BOUNDARY RESULTING IN LOCALLY HEAVY TOTALS.
LIMITED INSTABILITY WILL CAP THE MAGNITUDE OF TOTALS...HOWEVER
WITH THE GROUND SATURATED OVER THE AREA...THIS ADDITIONAL RAINFALL
WILL LIKELY STILL RESULT IN FLASH FLOOD CONCERNS. BEHIND THIS WAVE
LOOKS LIKE A DECENT SETUP FOR SOME SOUTHWEST TO NORTHEAST TRAINING
OF CONVECTION ALONG THE TRAILING BOUNDARY BEHIND THE WAVE.
CONTINUED MODERATE LOW LEVEL MOISTURE TRANSPORT INTO THIS BOUNDARY
SUPPORTS THIS TRAINING ACTIVITY. AGAIN RATES MAY NOT BE ALL THAT
HIGH...BUT CONTINUED STEADY TO LOCALLY HEAVY RAINS OVER THE
ALREADY SATURATED GROUND WILL EXACERBATE FLOODING CONCERNS. WPC
FORECAST CALLS FOR AN ADDITIONAL 1-3" (LOCALLY HIGHER) OF RAIN
THROUGH 12Z FRIDAY IN AN AXIS FROM NORTHEAST TX INTO CENTRAL AR.
SOME UNCERTAINTY WITH THIS EXACT AXIS...WITH WPC FAVORING
SOMETHING CLOSE TO THE A HIGH RES MODEL CONSENSUS...WHICH IS A
SLIGHT SHIFT NORTHWEST FROM OUR PREVIOUS FORECAST.

AS WE HEAD INTO THE DAY FRIDAY RAINFALL FROM THE FIRST WAVE WILL
CONTINUE TO SPREAD NORTHEAST ACROSS THE TN/OH VALLEY. TRAINING
SHOWERS AND EMBEDDED THUNDERSTORMS WILL LIKELY CONTINUE FURTHER
SOUTH ALONG THE FRONT ACROSS SOUTHERN AR. DURING FRIDAY WILL ALSO
SEE THE NEXT IN THE ROUND OF WAVES MOVE INTO TEXAS AS EVIDENCED BY
A DECENT SUBTROPICAL JET. THE COMBINATION OF LEFT EXIT JET
DYNAMICS AHEAD OF THIS SUBTROPICAL JET AND INCREASING 850 MB
MOISTURE TRANSPORT WILL LIKELY RESULT IN EXPANDING CONVECTION YET
AGAIN ACROSS PORTIONS OF NORTHEAST TX. THIS WILL SPREAD NORTHEAST
INTO SOUTHEAST OK AND WESTERN AR THROUGH FRIDAY AFTERNOON. GIVEN
SATURATED CONDITIONS...A CONTINUATION OF SIGNIFICANT FLOODING
CONCERNS IS EXPECTED. SOME MODEL SPREAD BY THIS TIME WAS NOTED. BY
THIS LEAD TIME CONFIDENCE IN THE MESOSCALE DETAILS WILL BE
LOWER...THUS SAW NO STRONG REASON TO DIFFER FROM A GENERAL MODEL
CONSENSUS. WPC THUS INCORPORATED THE LATEST GFS/ECMWF AND THE 12Z
HIGH RES GUIDANCE AND FOUND A MIDDLE GROUND SOLUTION FOR QPF
PLACEMENT. THIS RESULTS IN AN INCREASE IN MAGNITUDE AND A
SOUTHWESTWARD EXPANSION OF HIGHER QPF ON FRIDAY INTO NORTHEAST TX.

CHENARD







THIS DISCUSSION WILL TRANSITION TO MIXED-CASE FEB 26, 2018.  THE
LISTING OF ISOHYET POINTS CONTAINED BELOW WILL ALSO BE ELIMINATED
FROM THE PRODUCT FEB 26, 2018.  ISOHYET GRID INFORMATION WILL
CONTINUE TO BE GENERATED IN A VARIETY OF BINARY FORMATS AND MADE
AVAILABLE THROUGH THE WPC GIS PAGE.

24HR QP VT 24/00Z
 0.01 497326 493322 486319 482319 479318 471315 467311 465309
      464306 464286 460281 455276 447263 441253 439249 439245
      442239 451231 455226 454222 450220 452217 458214 469208
      478202 481201 481196 476190 475189 475184 476179 478176
      482170 484168 487169 498167 502167 505166 512167 517166
      521167 523170 525171 528175 531181 533185 536189 539193
      542195
 0.01 542739 542744 542750 542753 540756 539759 538762 537767
      537770 537775 538778 539780 542780 544777 545776 548774
 0.01 558117 557117 554116 552116 549118 547120 545122 544125
      543127 542130 541135 541138 542141 545142 549142 550140
      553141
 0.01 534733 531707 527696 525683 523678 521675 517671 514670
      508666 497670 492671 486672 478668 474669 471673 464680
      458681 453681 444685 433684 429682 427682 425679 426672
      426662 426657 424653 420653 415655 403670 396675 390681
      380698 374706 367712 361721 355728 352733 348736 343746
      340749 338746 339744 338742 335740 329745 328748 330751
      335751 334755 328761 321766 314768 312772 309775 308780
      311784 310788 308793 304795 298797 295794 282779 276780
      274783 273794 269793 267790 264782 266774 261770 257771
      253774 248775 243773 241773 236775 233777 231781 229790
      228794 228800 230814 232823 233826 230826 226827 226834
      228840 234849 241851 244847 242844 241834 245827 248820
      249814 251811 252809 255808 260811 262813 262817 257824
      256827 256833 257845 256850 258854 262856 266856 272849
      272840 273833 273826 272822 270820 270816 272814 272808
      274804 277805 279808 280813 282815 286817 288822 290825
      293826 304825 309824 312821 312816 312812 313809 326792
      336778 346761 352752 356743 360736 366731 369732 370735
      373741 371746 363764 360773 357782 355808 356811 359814
      361816 364812 369809 372809 374815 375822 374828 371833
      369838 366842 363849 358856 355862 350869 345877 343880
      338882 330885 325887 322886 325874 326868 330865 339860
      344858 346853 346851 340851 329852 309854 307856 307862
      306871 303875 298876 291877 289873 290869 290862 286858
      278859 275866 265882 263887 263894 263902 264907 268917
      274920 277919 279921 283925 290929 295936 296940 295943
      291951 286956 278961 270964 263968 259970 257973 255978
      253986 251989 246988 237991 236997 237002 239006 239012
      241016 244019 248021 254021 261021 265020 270026 277028
 0.01 277028 282025 283020 283018 279016 274015 272013 276012
      279012 281010 288008 296009 305013 311015 317014 323014
      329012 340004 368967 375959 384966 395973 405980 414985
      419988 424992 429002 437014 441018 446020 455015 464008
      469002 472996 477986 482972 487957 491942 494929 497913
      502896 503889 505880 508867 511851 513843 516836 520821
      533758 534733
 0.01 487141 485138 484138 482140 484141 485143 487141 487141
 0.01 470155 465135 457127 455122 451119 440112 437109 438104
      441099 441093 436092 430089 428087 435065 430054 427049
      423048 417050 413050 411047 401040 400035 398034 397037
      394043 395048 396053 394057 391060 386063 384063 383065
      382069 379067 375064 373063 369063 369070 370077 369086
      367090 363088 359089 356092 350103 347106 342107 339108
      337114 338120 340126 343131 345136 345142 350143 361142
      368143 375146 381148 380158 379165 377171 371178 362179
      348178 346171 344166 340163 333161 328159 321158 316161
      314165 315170 318173 322174 327173 333175 338178 342181
      344185 347191 351193 357196 361200 362202 361207 357209
      353211 350210 347203 343202 341204 342208 345211 348212
      350215 351221 357230 366235 367237 370236 372231 370225
      369218 373213 375211 376212 382215 385217 390218 395217
      405215 410214 412213 414215 414223 416219 418221 418225
      419229 420233 424232 429227 435225 440224 441221 442215
      440212 436208 432203 427193 424189 424184 424177 422173
      414171 408166 405163 402160 404156 409149 412145 417145
      422144 428144 433144 436148 443155 448165 451171 453174
      455174 466167 470155
 0.01 427099 427096 426094 424096 422098 424100 425100 427099
 0.01 351835 351833 351831 351828 349831 348833 348835 348838
      350837 351835 351835
 0.25 511294 506291 501285 492274 485263 482257 477252 472247
      468242 465238 468235 471234 476233 482237 488238 490235
      491230 494225 498230 502236 504244 507250 513255 524260
 0.25 502814 502808 500804 495798 490794 482799 477803 472808
      468816 463822 460829 458833 457839 455847 452857 450865
      448873 443881 442885 441892 439898 440908 440922 438933
      440942 443951 447960 452965 458969 462967 465965 473949
      477932 482909 488895 490885 491873 496856 498846 500834
      502814
 0.25 442767 441762 439755 438750 436745 434741 432739 430738
      427743 426748 427755 429759 431764 434768 437770 440769
      442767
 0.25 430805 430799 429795 426790 423788 421785 418778 415768
      413764 410762 405767 402776 395785 387797 386801 386808
      388817 387826 384833 378844 371858 363871 354883 339904
      332908 325910 323911 321912 319911 317907 313905 307904
      303904 301906 300909 301912 306917 312920 316919 317924
      313930 311939 310946 308954 308963 305970 295983 292988
      291992 293995 306994 317002 324003 330999 333996 334992
      336984 339979 343974 348969 352963 355956 361950 365944
      368938 370931 373925 376917 378910 394883 400871 403863
      404855 406847 412844 416842 417837 419827 430805
 0.25 422749 422747 421744 420742 418740 416739 414740 412741
      411744 410747 410749 411751 411753 412755 414755 416755
      417754 419753 420752 421751 422749
 0.25 402106 401103 401099 396094 393091 395087 396082 395076
      390075 390083 384087 383090 385094 388092 389095 390101
      392104 395106 398111 402106
 0.25 397117 397115 396113 396112 394114 392114 392116 391119
      392121 393121 395120 396119 397117 397117
 0.25 381202 381199 379197 377193 374190 371187 366185 361184
      358186 362189 365191 370194 373197 376200 380202 381202
 0.25 381119 378115 375114 376112 373108 374114 372118 367117
      360118 356122 355126 358128 364127 370124 375125 379121
      381119
 0.25 255010 256008 255006 255005 253004 252004 251005 250006
      250008 250010 251011 252012 253012 254012 255010
 0.50 521268 520268 518267 517267 515267 513267 512268 511269
      510270 509271 509272 508274 508277 508278 509281 510281
      511282 512284 514285
 0.50 467890 467888 466888 466890 466892 467890
 0.50 437758 436756 436753 436751 435749 434747 432747 431749
      431752 432754 432756 433759 434760 436760 437758
 0.50 414788 413781 410779 406782 402786 398792 396799 396807
      394812 392824 390830 387836 382845 376857 371866 365876
      350895 339913 332922 330924 326925 321928 316935 314938
      315942 317948 313963 308973 305978 305981 307981 310983
      311986 313992 317997 320998 324998 328994 331988 335979
      338974 341969 355951 359939 364929 368916 374905 378896
      385886 391874 394862 400836 404823 407810 412800 414788
 1.00 405806 405804 406801 404800 403802 401804 399806 399807
      399809 399811 400813 402813 403811 404808 405806 405806
 1.00 390854 390851 387849 382854 373868 366880 361887 356892
      352897 348904 343912 339918 330928 325935 323938 322943
      321951 321958 318968 316977 315985 315989 318991 323991
      326988 329980 332973 336967 342961 345954 350938 353930
      358923 373896 380882 384874 387865 390854
 1.50 384866 384861 382860 377865 369878 362889 358894 353900
      337923 330932 326939 324947 332955 327960 323967 320971
      318979 317987 321986 323984 328971 339960 341956 341948
      344941 348934 355924 362911 376885 379875 384866
 2.00 382866 380863 378866 372876 362892 357899 351906 348909
      346912 340921 335928 329937 326945 330945 336943 341938
      348931 353923 358914 367897 371889 374878 382866
 3.00 343923 343922 341923 339925 338926 337927 337928 336930
      335930 334932 334934 334935 334936 336937 336936 337936
      338934 339933 340932 341931 342930 342928 343925 343923

$$





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