Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 191918
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
217 PM EST MON FEB 19 2018


PRELIM DAY 1 QPF DISCUSSION
VALID FEB 20/0000 UTC THRU FEB 21/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

...LARGE SCALE HEAVY RAIN / FLOOD EVENT...
...EASTERN PLAINS / MID-UPPER MS VALLEY / GREAT LAKES / UPPER OHIO
VALLEY...

A SYNOPTIC PATTERN THAT SHOULD SPARK GREAT CONCERN OVER HEAVY
RAINFALL...WAS COMING INTO PLACE...WITH LARGE SCALE AMPLIFICATION
OF A TROUGH IN THE WEST...BLOCKED BY A 594 DECAMETER RIDGE IN THE
ATLANTIC...WITH MOISTURE TRAJECTORIES EMANATING FROM THE CARIBBEAN
BEFORE ENCOUNTERING A SLOW MOVING FRONTAL ZONE IN THE MIDDLE OF
THE NATION. MOISTURE QUALITY LOOKS MORE LIKE MARCH OR APRIL.
PRECIPITABLE WATER INCREASING TO AT LEAST 1.50 INCHES SOUTHERN
GREAT PLAINS AND TAPERING ONLY TO AROUND 1.30 INCHES TO THE
SOUTHERN GREAT LAKES WOULD REPRESENT MAX VALUES FOR LATE FEBRUARY
PER GEFS M-CLIMATE DATA. EXPECT REPEATED WAVES OF MODERATE
RAINFALL...AND EMBEDDED INCREASINGLY HEAVY RAINFALL FROM LATE
TONIGHT THROUGH WED/THU IN SOME AREAS...RESULTING IN A WIDE SWATH
THAT WILL INDUCE LOCAL FLASH FLOODING AND MAY OVERWHELM SOME MAIN
STEM RIVERS. ESPECIALLY CONCERNED IN THE SOUTHERN PLAINS / LOWER
MISSISSIPPI VALLEY WITH THE GREATEST AVAILABLE INSTABILITY...AND
THE SOUTHERN GREAT LAKES WHERE DEEP FROST DEPTH / FROZEN GROUND
AND SOME SNOW MELT WATER WILL EXACERBATE THE RUNOFF / FLOOD
SITUATION.

ALTHOUGH DETAILS WILL VARY EACH 6-HOURS...THE QPF WAS NOT OVERLY
COMPLICATED ON THE LARGE SCALE WITH THE SYNOPTIC PATTERN DRIVING
THE SITUATION...BEING WELL HANDLED BY THE MODELS. FOR DAY 1...00Z
TUE TO 00Z WED...WPC BEGAN WITH A 40/30/30 BLEND OF THE 12Z GFS /
12Z WRF-ARW / 12Z IN-HOUSE ENSEMBLE MINUS THE BIAS CORRECTION.
THIS RESULTED IN A CONTINUAL SWATH OF 1.0 TO 2.75 INCH AREAL
AVERAGE 24-HOUR RAINFALL FROM TEXAS TO MICHIGAN AND EVEN NORTHERN
NEW YORK. WITHIN THAT AXIS THERE WILL LIKELY BE HEAVIER MESOSCALE
AREAS. MOST LIKELY AREAS FOR ENHANCEMENT INCLUDE EASTERN OK INTO
ADJACENT MO/AR AS DEEP LAYER FORCING INCREASES TUESDAY...AND ALSO
IL/IN INTO LOWER MICHIGAN WHERE MOISTURE TRANSPORT AT THE NOSE OF
THE LLJ WILL BE MAXIMIZED FOR QUITE SOME TIME LATE TONIGHT AND ON
TUESDAY. THOUGH MODELS DO NOT INDICATE CAPE THAT FAR NORTH...THERE
IS USUALLY SOME AMOUNT OF CONVECTIVE ENHANCEMENT WITH SUCH STRONG
FORCING.


...ELSEWHERE...

LITTLE CHANGE TO THE FORECAST OUT WEST BENEATH THE DIGGING UPPER
TROUGH. THE SAME BLEND USED FOR THE EASTERN U.S. WAS APPLIED HERE
AS WELL. SOME OF THE HEAVIER SNOWFALL SHOULD OCCUR IN
WESTERN/CENTRAL COLORADO AND NORTHERN NEW MEXICO... SEE QPFHSD FOR
DETAILS.

BURKE

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



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 21/00Z
 0.01 530175 530169 528164 526160 523157 517150 511144 504137
      501136 497136 495138 497144 501152 505156 507159 510163
      514164 520170 523174 528176 530175
 0.01 516889 516881 515875 512862 508852 504844 501839 497838
      492838 488838 485841 483839 482834 481827 480819 475792
      473787 473780 473765 474752 476742 483725 488702 486688
      482677 475669 471668 468665 463656 457650 445637 441633
      436634 430635 426639 415654 410671 405690 402700 399710
      395719 391729 386738 384748 384754 385756 388757 392756
      394753 398746 400741 403743 410748 417756 418763 417771
      415781 412793 410804 405825 403830 400834 395842 384857
      379864 375869 365883 358892 350897 347901 341901 337899
      333895 329893 326890 322882 315864 307860 299857 294857
      291860 288864 287871 288886 289891 284888 282885 280888
      281891 282897 285903 286908 291908 295907 299910 304914
      317915 324917 333921 330924 324925 316921 304922 296925
      289931 283937 281939 282943 284951 280959 277963 274968
      273972 277976 277996 275001 276005 279013 291025 296025
      300024 308020 322007 337000 354989 362984 369980 375979
      380986 384986 389985 395979 397976 401974 411972 413975
      413981 409992 407998 404002 399011 390025 387029 387036
      391038 393042 390045 387046 378042 373041 368043 361047
      353052 344053 333053 327052 325052 324055 324061 327062
      337066 342069 344073 342078 341079 338078 327076 319080
      309079 302085 299088 298092 300095 305096 307106 311114
      315116 320117 324115 327113 331111 335112 339114 345114
      348107 350100 353097 357095 361091 363089 366090 370091
      373093 375098 375105 376110 370134 370138 372142 376144
      382145 388139 391130 394133 398132 401132 402129 405128
 0.01 405128 412129 415123 418125 420127 421130 421135 418145
      418150 417152 412160 409159 410152 404151 402157 399159
      396159 392162 388166 387175 406167 413167 415167 417164
      418156 420152 422150 424143 425141 428142 432147 437150
      439153 444151 454145 454142 453141 446139 437129 431118
      426117 423115 423112 415110 414106 417104 421102 424103
      431104 438105 439104 439099 435097 432095 430092 426088
      419087 418082 420079 425075 434071 440060 446055 449051
      453047 456040 459035 462030 466024 469021 473014 475007
      476999 479992 484980 491967 494962 496957 503945 506939
      509934 512929 514921 516889
 0.01 481244 482239 481235 479233 476233 472226 470218 470213
      469210 466209 462210 451217 448218 444215 438211 431207
      424204 422202 418201 411202 405205 403208 405212 408214
      411213 417209 420208 422210 426212 428215 428219 427223
      431229 429234 427235 418234 412237 407241 402246 399248
      398253 399256 401259 410262 416266 423266 449259 455257
      462257 468255 474252 479249 481244
 0.01 396205 394202 391199 390196 386194 380191 374186 368182
      364181 361182 359183 360186 367190 374193 378196 379199
      381202 384205 387207 392208 396205
 0.01 402102 401099 397099 394099 390099 388100 386102 384104
      382108 382113 385114 387113 391112 393111 396110 397108
      398105 401104 402102
 0.01 376751 373748 370747 362754 352759 345760 341763 334769
      335777 337782 338784 341785 343784 353780 357777 360772
      363768 367764 370761 373757 376751
 0.01 355832 355830 355828 353826 351828 350831 349833 349835
      350837 352837 353835 355833 355832
 0.01 355863 351857 344853 335850 330843 326842 323844 320851
      322855 322859 324863 324866 326869 328872 332874 336876
      339873 343871 346873 352868 355863
 0.01 328170 329168 329166 329164 327161 326160 324158 322158
      320159 320160 319162 319164 319166 321167 322169 324170
      326170 328170 328170
 0.01 308841 308831 302825 296821 290816 281804 276798 271791
      267786 262778 260778 258782 256785 256787 261805 269808
      273810 275813 283827 293837 300841 307844 308841
 0.01 282088 283081 282076 275069 270062 266058 261056 248055
      244058 243064 244069 247074 254080 262085 266089 271090
      277090 282088 282088
 0.01 262852 262847 260844 258836 254829 252820 251810 249802
      242791 235786 229787 227793 228803 230805 230811 231820
      232830 236836 238838 240842 242849 246855 253857 257857
      260856 262852
 0.01 260002 260998 257997 249995 249989 247987 243988 239989
      235987 233987 230989 231993 233996 238001 244005 249009
      256007 260002
 0.25 495901 495895 494891 490896 487903 485906 482909 477913
      474921 469926 465932 463942 461947 459949 453952 447957
      438967 433973 429980 426985 422993 419000 418004 420006
      422009 423013 422023 421026 421031 425031 428029 433023
      437017 443002 448995 452990 457985 460978 466961 467957
      469953 474948 480944 485939 488932 491924 495901
 0.25 471706 471696 469691 464690 460686 458681 457673 455664
      453658 451653 449651 446651 441656 437653 432653 428654
      424658 423661 421674 417684 417692 419700 420708 422714
      427714 431711 434707 437706 436714 435720 434726 434730
      434736 431737 427739 425746 427757 428766 427773 424783
      421792 414817 407838 398860 393869 388877 376895 364911
      350926 344932 337938 330945 322952 314956 304960 300963
      299966 301972 302976 301979 291993 288999 287006 289010
      293012 299013 303012 308009 311005 326993 334987 342984
      360974 377965 391965 395962 397958 403951 409941 421926
      436912 444888 448880 454872 459862 461847 463834 463817
      462788 462774 463760 466734 467726 468717 471706
 0.25 459242 458241 456241 454241 452242 450244 448246 450247
      451247 453246 455246 457245 458244 459242 459242
 0.25 408058 409054 406051 402052 398055 395062 392066 389067
      387070 387075 389077 392080 395078 398074 401069 405063
      408058
 0.25 382078 381074 380069 378064 375062 370060 365061 366066
      369070 372073 374076 377080 381081 382078
 0.25 370055 370054 368053 368054 368055 370055 370055
 0.25 265072 265068 264066 262063 260061 257061 255061 251062
      250065 251069 252071 254072 257073 260074 262074 265072
 0.25 252842 250838 249833 249831 248827 246823 243819 241820
      241825 242829 244833 247835 249841 252843 252842
 0.25 251002 251001 250000 249999 247998 246996 244996 242995
      240995 240996 241998 242999 243000 244001 245002 246002
      247002 249003 251002 251002
 0.50 460714 459709 456706 451706 447708 442709 440713 439724
      437740 434743 432748 431753 431759 430770 429781 423799
      419817 412835 406851 398867 381895 371909 361921 350931
      337942 325952 318957 312960 310964 311968 312971 312975
      302987 297994 295998 295001 297004 300007 304006 307003
      317993 330983 345976 360970 372963 379958 388955 391958
      394955 398949 404941 408934 412926 416921 427908 432901
      436893 439884 442875 447867 450858 454840 456829 457817
      457792 458780 457769 459746 459736 459727 460714
 0.50 376069 375066 373066 372066 373067 374068 374070 376069
 1.00 451757 452751 451746 448743 445743 441743 438746 435753
      431788 427804 423820 418835 411849 405862 398875 383900
      376911 367921 346938 337947 327956 323961 323965 321968
      318975 314979 309985 307987 308992 313990 318985 328977
      339970 345967 352965 357965 363962 369959 374955 379952
      384945 387940 392935 394938 396938 401933 401927 405922
      414912 422900 430887 435876 441858 445843 448834 449825
      451808 450785 450768 451757
 1.50 445766 445756 445751 442749 438754 436761 434776 433792
      429806 427824 424829 422834 416847 403871 397882 391892
      385904 378914 370923 366927 361931 355933 351937 342945
      334954 328965 325970 320975 323976 327973 332970 336966
      345960 357954 363952 364952 366955 367956 370954 374951
      386929 400907 409909 414905 417900 424889 430877 434864
      439849 442835 444819 446812 445802 444792 445782 445766
 2.00 440774 441772 440769 439770 438770 437772 437775 437777
      437779 439779 440777 440774 440774
 2.00 441813 441810 441808 440806 440804 439803 438802 436802
      434803 433804 433805 432807 431809 431812 431814 432816
      434818 435818 435819 437818 439818 440815 440814 441813
 2.00 437837 435834 433837 428843 423844 420846 415853 400883
      384911 373925 369931 363935 354938 348943 343947 337953
      335956 337959 341959 345956 350952 357949 361947 363944
      365940 367939 369941 372941 375939 380934 398906 407891
      410889 414887 417889 420888 425881 428873 431864 433854
      435843 437837

$$





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