Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 291839
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
238 PM EDT FRI AUG 29 2014


PRELIM DAY 1 QPF DISCUSSION
VALID AUG 30/0000 UTC THRU AUG 31/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

UPPER MS VALLEY INTO THE UPPER LAKES

PW VALUES FORECAST TO REMAIN ABOVE AVERAGE---1.5 TO 2+ STANDARD
DEVIATIONS ABOVE THE MEAN---FROM THE UPPER MS VALLEY INTO THE
UPPER LAKES DAY 1.  CONVECTION LIKELY TO REMAIN ACTIVE IN THIS
HIGH PW AXIS AS THE UPPER TROF MOVING OUT OF THE CENTRAL PLAINS
PUSHES THROUGH THE UPPER MS VALLEY TONIGHT AND INTO THE UPPER
LAKES REGION SATURDAY.   WELL DEFINED UPPER DIFFLUENCE AHEAD OF
THESE HEIGHT FALLS WILL ENHANCE UVVS ACROSS THESE REGIONS---WITH
OVERALL GOOD MODEL CONSENSUS FOR HEAVY RAINS.  THERE IS THE USUAL
AMOUNT OF LATITUDINAL DIFFERENCES WITH THE QPF AXIS---WITH THE IN
HOUSE PSEUDO BIAS CORRECTED MEAN USED FOR THE AXIS.  THERE MAY BE
A PERIOD OF TRAINING OR SLOW MOVEMENT OF CELLS ACROSS THESE
AREAS--WITH ISOLATED EXCESSIVE AMOUNTS POSSIBLE.

WESTERN GULF COAST INTO THE LOWER MS VALLEY

AT LEAST TWO SLOW MOVING LOW TO MID LEVEL CIRCULATION OVER THE
WESTERN GULF OF MEXICO WILL KEEP CONVECTION ACTIVE ACROSS THIS
AREA DAY 1.  THERE SEEMS TO BE GENERAL AGREEMENT THAT ONE CENTER
MAY BE LIFTED NORTHEASTWARD INTO THE LOWER MS VALLEY---ON THE
SOUTHEAST SIDE OF THE UPPER MS VALLEY TROF---WHILE THE CIRCULATION
OFF THE SOUTH TX COAST MOVES LITTLE.  WITH PW VALUES 1.5-2+
STANDARD DEVIATIONS ABOVE THE MEAN OVER THE WESTERN GULF IN THE
VICINITY OF THESE CIRCULATIONS---HEAVY PRECIPITATION POTENTIAL
WILL PERSIST DAY 1.  THAT SAID---CONFIDENCE STILL IS NOT GREAT
WITH QPF DETAILS WITH BOTH SYSTEMS AS THERE ARE DIFFERENCES IN HOW
QUICKLY ONE VORT IS PICKED UP TO THE NORTHEAST AND THE CONVECTIVE
DETAILS NEAR THE SLOW MOVING VORT OFF THE SOUTH TX COAST---THAT
WILL LIKELY REMAIN POORLY DEPICTED IN THE MODELS.  VERY HEAVY
RAINFALL AMOUNTS POSSIBLE WITH BOTH VORTS---WITH POTENTIAL FOR
ISOLATED VERY HEAVY TO EXCESSIVE RAINFALL AMOUNTS.  THE IN HOUSE
PSEUDO BIAS CORRECTED ENSEMBLE MEAN FOLLOWED MORE CLOSELY TO
MITIGATE THE SPREAD IN THE MODEL SOLUTIONS.

LOWER TO MIDDLE MS VALLEY/LOWER OH VALLEY

IN BETWEEN THE EXPECTED PRECIPITATION MAXIMUM OVER THE UPPER MS
VALLEY/UPPER LAKES AND THE MAX OVER THE LOWER MS VALLEY/WESTERN
GULF COAST REGION---MODEL CONSENSUS IS FOR LIGHTER TOTALS FROM
PORTIONS OF THE LOWER TO MID MS VALLEY/LOWER OH VALLEY.  DAY 1 QPF
DID NOT DEVIATE FROM THIS DEPICTION---ALTHOUGH WITH ABUNDANT
MOISTURE ALSO FORECAST TO REMAIN ACROSS THESE REGIONS---HEAVIER
PRECIPITATION TOTALS ARE STILL POSSIBLE.

NORTHERN ROCKIES INTO THE NORTHERN PLAINS

NO BIG DIFFERENCES DAY 1 WITH THE INLAND MOVEMENT OF HEIGHT FALLS
AND THE ASSOCIATED FRONTAL BOUNDARY FROM THE NORTHERN ROCKIES
TONIGHT AND INTO THE NORTHERN PLAINS DURING THE DAY ON SATURDAY.
A NARROW BAND OF ABOVE AVERAGE PW VALUES ALONG AND AHEAD OF THE
FRONT WILL SUPPORT SCATTERED CONVECTIVE POTENTIAL FROM THE
NORTHERN ROCKIES INTO THE NORTHERN PLAINS.  THE MODEL CONSENSUS IS
FOR LIGHT TO MODERATE AMOUNTS AHEAD OF THIS FAST MOVING FRONT.
THE DAY 1 QPF DID NOT DEVIATE FROM THIS IDEA.

ORAVEC

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

24HR QP VT 31/00Z
 0.01 555125 556112 557097 557092 556086 552078 544068 539066
      537064 532065 524064 520063 522060 534053 539048 542041
      543030 540022 539019 535016 529015 513016 486020 478021
      471023 466023 463024 456027 443030 440031 438034 438045
      439048 438054 438060 438065 441074 442080 440086 439089
      434090 427087 426088 425093 426101 425103 426107 429114
      432117 436119 438122 438129 437141 437146 438152 440158
      443164 447169 451176 454179 455174 459165 463161 468158
      473152 476147 480140 481135 479131 477127 477120 478114
      480110 482099 486091 489085 493079 497073 502069 500092
      500104 502111 508112 510107 513106 522119 530135 534142
      538146 542147 544146 548139 550135 552131 555125
 0.01 536220 537213 537207 538198 537192 529175 525166 519157
      514151 511148 506147 499151 495159 497182 495187 496192
      495201 494205 492206 483204 478207 470210 466212 463215
      460219 462222 465225 469225 477223 481224 484224 483227
      488234 485237 483237 481234 480231 476230 467232 465235
      464242 465247 468250 471252 475255 481262 487270 492276
      494280 499284 505286 509286 515280 517275 518268 519252
      517241 515231 513226 517225 524228 527228 530227 536220
 0.01 225058 227065 229069 231070 237075 243079 249084 255087
      269094 271096 275096 282095 287095 289093 288087 288079
      291075 286070 280067 275063 269060 262056 256051 245042
      242039 241035 241025 249014 260007 281993 292986 299982
      305979 319971 325967 330967 334969 339969 348969 358962
      369955 375952 377950 379952 392957 407962 415964 422961
      433953 444947 455939 461935 465927 472915 479903 487889
      495871 500855 505838 508831 509821 512813 513802 514794
      515785 517765 517756 514755 512752 509723 507711 506704
      504704 492701 489703 487707 483713 480720 477728 475736
      472743 470750 466757 462763 457770 440796 431806 420815
      409826 404829 400834 394837 386838 382840 378841 373841
      370839 362835 356831 343826 337823 330821 325818 319816
      308811 294806 289803 282802 274800 269801 265802 258806
      255812 258817 260820 263822 273831 282841 287846 288849
      287852 285859 282866 280872 277878 270892 265898 260903
      257905 255908 253915 246927 242933 240940 237945 237954
      236963 235971 235979 234985 230997
 0.01 517064 516062 514064 515065 517064 517064
 0.01 359750 358744 357739 354739 351741 346746 341751 336756
      334759 333763 334768 336771 338773 342772 347768 352763
      356757 359750
 0.25 529210 528199 528193 526188 521179 516171 510165 505161
      503162 502166 502171 503177 505182 510191 511196 514200
      515204 520207 523208 526212 529210
 0.25 511276 512268 512261 511249 510245 507242 502233 498224
      495224 495228 496234 500241 502246 503252 501259 498258
      495258 494262 495267 497273 500277 506279 511276
 0.25 504800 504792 504784 502777 500768 498762 495756 493754
      493751 493746 490748 488753 484761 478770 474780 470790
      465799 452817 442833 432852 428860 421868 417872 413875
      403879 393880 383879 371878 364874 356869 351867 345866
      340866 333866 329869 326872 319880 312886 307886 305884
      303874 256927 252936 250947 246960 245965 245972 246977
      248981 251984 255986 261987 266987 274982 281977 289971
      298965 307960 315956 322951 330946 339944 348941 357936
      375925 383921 392919 403919 407922 410925 416933 419937
      424938 430938 435936 443930 451924 459918 464913 469905
      474896 480886 485875 489865 496842 501819 504800
 0.25 459113 460109 458106 456105 454105 451105 447104 445106
      444111 444116 445118 446121 449122 451122 455122 457120
      458116 459113
 0.25 291818 290816 288815 286815 286814 284814 283815 283817
      284817 286818 288819 290819 291818
 0.25 282815 281813 280813 279813 278813 279814 280815 281815
      282815
 0.50 498806 497800 495798 493784 489779 486777 484780 476795
      469811 452837 449844 448856 445865 442873 439880 434886
      426900 421905 419909 417913 418921 421928 424931 428931
      435928 447919 460910 464906 468900 473892 477885 483869
      486860 489851 491843 494833 496817 498806
 0.50 353897 350890 348888 344887 335887 328889 315894 308897
      300898 293900 286904 277911 272916 268921 262933 259939
      256947 253962 254970 257976 263980 268979 275976 281973
      290964 295960 301957 308954 312952 331932 348910 352904
      353897
 1.00 481859 482854 480850 477850 469858 462869 455879 449889
      441899 440902 441906 446908 457903 465894 471885 475879
      477872 481859
 1.00 334911 334904 333899 328900 324902 316905 308907 298911
      289912 281917 276923 269939 267950 267956 268962 270964
      276964 283961 297952 304947 310942 321930 327923 332916
      334911
 1.50 320917 319915 315914 310913 300916 293915 288917 284921
      281925 276936 274944 276950 281953 285954 295947 303940
      310932 317922 320917
 2.00 305930 306926 305922 299920 294919 288922 285927 282931
      280937 280941 281945 285947 290947 295943 299939 302935
      305930

$$




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