Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 240700
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
259 AM EDT THU JUL 24 2014


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


DAY 1...

...COLD FRONT PUSHING THRU THE EASTERN HALF OF THE NATION...

MODELS CONTINUE TO BE IN GOOD AGREEMENT IN MANY ASPECTS OF HOW THE
FRONT PROGRESSES EAST TODAY.  CAPE AHEAD OF THE FRONT SHOULD BE
LIMITED GIVEN MODEST LOW/MID LEVEL LAPSE RATES.  HAVING SAID
THAT...SURFACE LOW PRESSURE ALONG THE FRONT IN EASTERN NC AND FAR
SOUTHEAST VA WILL PROVIDE A FOCUS FOR CONVECTION TO ORGANIZE.
GIVEN PRECIPITABLE WATER VALUES AT OR ABOVE 2 INCHES AND FAIRLY
WEAK FLOW IN THE STEERING LAYER...WPC PLACED A MAX OF 1 TO 2
INCHES IN THIS REGION.  LOCALLY HIGHER AMOUNTS ARE LIKELY TO BE
EMBEDDED WITHIN THIS AREA.  ELSEWHERE...GENERALLY LIGHTER AMOUNTS
ARE SHOWN ALONG THE FRONT...BUT AGAIN ISOLATED HIGHER AMOUNTS ARE
POSSIBLE.

...LOWER MS VALLEY/CENTRAL GULF COAST REGION...

THE CLOSED MID/UPPER LEVEL LOW OVER THE LOWER MS VALLEY AT THIS
TIME REMAINS STUCK IN PLACE BETWEEN TWO LARGE RIDGE AXES CENTERED
OVER THE SRN HIGH PLAINS AND NEAR THE BAHAMAS. THIS FEATURE SHOULD
SLOWLY SHEAR OVER TIME WITH RELATIVELY WEAK 850 MB FLOW TODAY.
CELLS CAPABLE OF PRODUCING LOCALIZED HEAVIER RAINFALL CAN BE
EXPECTED NEAR THE CNTRL GULF COAST BUT THE CONTINUED
DISORGANIZATION OF THE UPPER FEATURE SHOULD KEEP OVERALL RAINFALL
SCATTERED IN NATURE.

...PACIFIC NORTHWEST...

A DEEP 500 MB LOW...SOME 2 TO 3 STANDARDIZED HEIGHT ANOMALIES
BELOW NORMAL...ALONG THE WEST COAST OF WA AT 24/06Z WILL CURVE
NORTHEAST AND MAKE ITS WAY TO NEAR THE ALBERTA/SASKATCHEWAN BORDER
BY THE END OF FRIDAY MORNING.  THE MAIN MOISTURE AXIS WILL PUSH
INLAND WHILE WEAKENING AS THE FRONT MOVES INLAND THROUGH THE EARLY
MORNING HOURS. SHOWERY ONSHORE FLOW WILL FAVOR THE NRN CASCADES
AFTER THE CLOSED LOW MOVES INLAND.

THE 24/00Z MODELS SHOWED GOOD AGREEMENT WITH THIS SYSTEM...SO USED
A GENERAL MODEL COMPROMISE FOR THE PLACEMENT QPF AND THEN
INCORPORATED THE HI RES GUIDANCE FOR PCPN AMOUNTS IN THE COMPLEX
TERRAIN.


...NORTHERN ROCKIES INTO THE NORTHERN PLAINS...

ONGOING CONVECTION OVER THE NORTHERN ROCKIES WAS BEING AIDED BY
ISENTROPIC LIFT NORTH OF A DEVELOPING SFC WARM FRONT OVER EASTERN
MT AND MID/UPPER LEVEL SPEED MAX WHICH HAD RACED IN FROM THE
SOUTHWEST.  THE 23/12Z ECMWF CONTINUED TO STRUGGLE WITH THIS AND
WE CONTINUED TO GIVE IT THE LEAST WEIGHTING.  THE 24/00Z NAM
SLOWED DOWN WHILE THE 24/00Z GFS SPED UP THE MOVEMENT OF THE LOW
AS IT COMES IN...WITH CORRESPONDING ADJUSTMENTS IN PRECIPITATION.
WPC LARGELY USED THE PSEUDO BIAS CORRECTED GUIDANCE FOR PLACEMENT
INTO THE EARLY MORNING HOURS.

BY THE LATTER PART OF DAY 1...THE ECMWF SEEMED TO GET A BETTER
HANDLE WITH THE DEVELOPMENT OF CONVECTION ACROSS THE NORTHERN
PLAINS.  THE NAM/GFS TENDED TO LARGELY BE DRY...PERHAPS A FUNCTION
OF THE WARM MID LEVEL TEMPS ON THE PERIPHERY OF AN UPPER HIGH
LOCATED OVER WESTERN UNITED STATES.  BUT THE NAM/GFS/UKMET ALL
ACCELERATE THE LOW LEVEL FLOW IN RESPONSE TO HEIGHT FALLS COMING
OUT OF THE NORTHERN ROCKIES...WITH THE NAM GENERATING 60 KTS OF
SOUTHWESTERLY FLOW AT H85 FEEDING INTO IA.  FORECAST SOUNDINGS
SHOW THAT WARM LOW LEVEL ADVECTION COMBINED WITH INCREASINGLY
STRONG ASCENT IN THE LOW/MID LEVELS SHOULD BE ENOUGH TO INCREASE
LAPSE RATES ENOUGH FOR SOME CONVECTION TO DEVELOP LATE THU NIGHT
OR EARLY FRIDAY MORNING.  GIVEN THE FORCING...AND SUPPORT OF THE
STORM SCALE ENSEMBLE AND ARW...WE WENT ABOVE THE GLOBAL MODEL QPF
GUIDANCE HERE ONCE THE LOW LEVEL JET FORMS LATER TONIGHT.

BANN

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

24HR QP VT 25/12Z
 0.01 466622 465630 464635 462651 458661 454672 448685 440700
      437706 432711 427712 424708 419704 416707 409717 406721
      404726 401738 390802 381826 377837 372846 365856 359866
      354872 351881 345893 343908 341915 341923 339928 339934
      336939 332937 328932 326925 324923 322927 320935 314947
      311962 309969 308975 305981 301983 277987 274992 274002
      270008 269012 265014 259015 256011 253006 250000 249993
      249986 252974 249971 248966 248961 252956 261947 273941
      276940 278938 280932 275929 272921 275911 278898 276894
      276886 276879 277873 279867 280862 278860 272849 264837
      260832 254828 250826 246823 243818 240811 239805 237801
      238790 241785 246780 252777 260776 265778 267782 267786
      265791 263794 266796 281779 292762 297758 302755 307748
      310742 313736 315731 323720 329711 333706 336701 342695
      347690 351687 357683 363680 368677 376674 382670 388666
      399657 403652 407649 417638
 0.01 555097 557080 556068 556053 557045 556038 554028 551020
      548011 544003 533988 528981 522974 517970 513969 506963
      499957 491949 485941 484937 481933 473916 469907 465902
      453894 445891 441889 435889 430887 423887 411889 408891
      406896 404902 404910 409931 414940 418946 418952 417957
      416965 417971 426984 429986 433986 436984 440984 446991
      451999 457009 459013 464018 468019 469014 471012 474010
      476017 479026 475036 473042 470045 467047 462046 458037
      458031 456027 451022 445019 440018 437016 428015 423015
      418017 410020 406022 402023 398025 395029 391038 387044
      383047 380048 377048 372048 363051 359054 357056 357062
      358066 358069 357072 352075 354082 355086 353090 346093
      340091 338094 339098 342107 344116 342120 339126 337128
      336135 338139 345141 355140 363136 371131 378125 382118
      389114 394115 398113 402108 404104 405100 405094 408090
      413084 416081 418076 423067 427056 430050 434052 435054
      440062 441066 440069 438074 437079 441077 448073 457078
      459080 461082 459084 457086 459092 460097 464099 464109
      466112 470113 472116 476117 479116 482112 483105 484098
      480092 477090 476086 476081 479078 483078 484081 484088
      486092 486099 487106 493117 496122 496127 490132 483134
      476129 468127 461131 457136 454142 454146 454149 455155
      454163 456162 463156 469150 476157 479163 479165 477170
      478175 482179 484185 485192 488195 486200 483202 477205
      470208 463214 458216 455223 456228 458231 456234 453237
      449239 450242 452245 457246 468245 473246 479248 485250
      486255 488260 492265 495273 501281 506283 510283 515277
      518268 516257 525249 527234 531225 538202 542198 544191
      544187 545178 544163 544154 545143 551118 555097
 0.01 502831 502821 499814 496807 495802 494797 493787 494777
      493766 492754 491749 489747 482748 478752 475760 473778
      474785 474790 476793 480799 482803 482806 484812 485816
      488823 496833 497835 500835 502831
 0.01 467974 467972 467971 467969 467967 466965 464967 462969
      460969 459971 459974 460975 461976 462978 463979 464980
      464981 465983 467981 467979 467976 467974 467974
 0.01 325803 324801 321800 318802 313803 307804 302805 296805
      292804 295807 298808 304808 308809 313808 316806 322805
      325803
 0.01 319123 319121 318118 315116 313115 311113 307112 305112
      305115 307117 308119 312122 314122 317123 319123
 0.01 293109 294103 294098 289089 277079 268066 262060 259051
      258047 255044 249044 245045 240045 238047 234051 233055
      230064 230070 232073 240077 246083 252088 260093 266097
      276100 281101 283104 289110 293109
 0.25 451627 451634 451638 453640 454646 451651 437672 434677
      430682 426680 422683 406703 395720 392726 390732 389738
      388746 386774 385789 384797 381803 377814 372822 367825
      358827 353825 349821 345817 343811 340799 338793 335787
      331783 323782 318781 316779 316775 316770 318764 324752
      329742 335733 340726 356707 370691 378683 389676 400670
      410669 416667 421662 429654 436644 441630
 0.25 547079 548073 548066 548058 547044 545033 543025 540017
      536008 532002 523992 518987 512982 506979 502979 500980
      501001 499005 495005 490007 488009 487015 489025 493033
      497038 503044 504047 501049 495052 489053 482056 478062
      477067 480067 484067 492070 499066 503066 505069 509074
      511082 514093 516096 518096 524092 529088 531085 535085
      538088 543087 546083 547079
 0.25 538175 538163 538153 540139 541133 540127 538123 535120
      528117 524110 520108 516109 510115 510123 512144 511150
      507150 504149 501150 498161 493171 495180 497187 501199
      498206 490205 485207 480208 476210 470215 468219 469221
      471222 477220 481220 484223 489225 492228 499242 501247
      505250 507250 509249 511247 517230 514221 513217 516214
      523212 528210 531207 533200 534190 535179 538175
 0.25 458942 458936 457932 453925 449919 444913 439909 433905
      426903 419907 415911 413915 413921 419936 423942 428948
      430955 436961 440966 443966 445964 443951 451950 454948
      457945 458942
 0.25 405070 406068 406065 406063 405062 404060 403060 402061
      400062 398064 396066 395069 396071 396072 396073 397074
      399074 400074 401073 403073 404072 405071 405070
 0.25 394080 394073 392071 391067 388072 386072 384070 382065
      378067 376073 373080 373083 376085 381084 388086 392082
      394080
 0.25 355841 355839 352839 349842 345842 342842 340845 337849
      336852 333851 325842 321843 319847 315858 314870 312878
      309882 302889 299894 298901 299915 301921 305926 308926
      311922 315911 319901 323887 327878 332865 335856 338860
      342860 344858 351851 355841
 0.25 295883 294878 293876 290875 287879 285883 285887 284894
      283898 286902 289902 291899 292893 293889 294884 295883
 0.25 283825 281822 279821 277819 274818 272817 268817 264818
      264819 266821 270822 272823 275824 278825 280826 283825
 0.25 272085 270079 266072 262068 257063 252059 246060 241066
      244072 249077 254081 260086 267088 272085
 0.50 544068 544058 541049 540039 536031 532030 530028 525023
      520019 513014 508014 501016 498018 497022 501029 505035
      510041 514046 516051 516056 517061 520063 523062 527061
      531067 537072 542073 544068
 0.50 536139 536135 534131 528129 522131 520133 519138 519147
      520154 516160 512168 510171 506171 503171 501175 503183
      506192 510197 517201 521204 524205 527203 528196 529186
      529172 529164 532154 533149 534145 536139
 0.50 513234 513230 511226 510222 506220 504223 502220 498211
      496209 492209 488216 489219 491222 495231 498237 504237
      510236 513234
 0.50 483214 483212 482211 481210 480211 479212 478213 479214
      480215 482215 483214
 0.50 443652 442651 441652 439653 441653 442652 443652
 0.50 440655 439653 438655 436656 435658 433660 432662 431663
      430664 429666 431667 432665 434664 435662 435661 437660
      438658 440656 440655
 0.50 450937 448928 447923 443918 436914 429911 424911 421913
      418916 418924 419928 421933 427940 433945 438946 443946
      447944 450940 450937
 0.50 397686 396684 392685 387687 381688 375692 367701 358713
      343734 337744 331757 330764 333768 335771 339772 341774
      342779 344787 346794 351799 353801 358801 364802 367801
      372796 375794 376790 377782 378775 379766 380757 378739
      379732 382724 386712 393699 395693 397686
 0.50 267085 267081 266078 264076 263074 260072 258070 256069
      253068 251071 252074 254076 256078 257080 259082 262084
      264085 267085
 1.00 442937 443933 442929 440928 437926 435924 433923 429922
      426923 425926 425931 426933 428936 431937 433938 437939
      440939 442937
 1.00 376703 375701 375700 373701 372703 371704 370706 370707
      369709 368709 368712 368714 370715 371713 373711 374708
      375706 375705 376703
 1.00 373767 371763 370759 368757 364756 362753 363749 362739
      363734 363733 359733 356736 353737 348745 346755 349758
      349767 351774 350780 352784 355785 358785 363782 366779
      372770 373767
 1.50 365771 365769 364768 362768 360769 360770 359772 359773
      358774 359775 361775 362774 363773 364772 365771

$$




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