Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 210658
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
258 AM EDT SUN SEP 21 2014


PRELIM DAY 1 QPF DISCUSSION
VALID SEP 21/1200 UTC THRU SEP 22/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR



DAY 1...


GREAT BASIN TO THE CENTRAL ROCKIES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

AXIS OF HIGHLY ANOMALOUS PWS (3.0-4.0 STANDARD DEVIATIONS ABOVE
NORMAL PER THE SREF/GEFS) WILL CONTINUE TO PULL NORTHWARD INTO THE
AREA EARLY IN THE PERIOD AHEAD OF THE MID/UPPER LEVEL LOW
CURRENTLY ACROSS CENTRAL CA. MEANWHILE...LARGE-SCALE FORCING
(UPPER DIVERGENCE/DIFFLUENCE AND DEEP-LAYER ASCENT) WILL CONTINUE
TODAY AHEAD OF THE MID/UPPER LEVEL LOW...ALLOWING FOR MORE
WIDESPREAD SHOWERS/TSMS AND SOMEWHAT ATYPICAL AREAL-AVERAGE
RAINFALL FOR THE TIME OF YEAR (GENERALLY .25 TO .75 INCH...WITH
HIGHEST AMOUNTS GENERALLY ACROSS THE HIGHER TERRAIN WITH THE
UPSLOPE ENHANCEMENT).


NEW MEXICO INTO WESTERN TEXAS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

RATHER STAGNANT PATTERN ACROSS THE AREA DURING THIS PERIOD...WITH
LITTLE SHIFT IN THE FEATURES ALOFT WHILE THE FAVORABLE
THERMODYNAMIC PROFILE REMAINS IN PLACE. ONCE AGAIN...LARGE-SCALE
FORCING WILL BE LACKING UNDERNEATH THE BROAD UPPER
RIDGE...HOWEVER...PERSISTENT WEAK UPPER LEVEL DIFFLUENCE BETWEEN
THE CLOSED UPPER HIGH ACROSS WRN MEXICO AND THE FASTER
WESTERLIES/HEIGHT FALLS DROPPING INTO THE MID MS VLY WILL ALLOW
FOR THE DEVELOPMENT OF MORE ORGANIZED CONVECTION...AIDED AGAIN BY
THE PERSISTENT E-SE (UPSLOPE) LOW-LEVEL FLOW AND MOISTURE
TRANSPORT. WPC UTILIZED A MULTI-MODEL BLEND WITH THE
QPF...INCORPORATING SOME OF THE HIGHER RESOLUTION DATA THAT
APPEARS TO BE VERIFYING BETTER IN THE NEAR TERM (NSSL
WRF...WRF-ARW...AND SSEO MEAN)...WHICH MAINTAINS DECENT CONTINUITY
FROM THE PREVIOUS WPC FORECAST AND ALIGNS WELL WITH THE REFORECAST
DATA FROM THE 00Z 09/20 CYCLE. AREAL AVERAGE AMOUNTS RANGE BETWEEN
0.50-1.5 INCHES...HOWEVER...PER THE AFOREMENTIONED 4KM
GUIDANCE...LOCALIZED AMOUNTS OF 2-5 INCHES ARE EXPECTED
(ESPECIALLY INTO ERN NM)...WHICH GIVEN THE RELATIVELY LOW 1-3 HR
FFG...WILL MAINTAIN A FLASH FLOOD THREAT.



GREAT LAKES INTO THE NORTHEAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

A STRONG UPPER JET STREAK (110+ KTS AT 250 MB) WILL STEER INTO THE
UPPER MS VALLEY TONIGHT. THE JET STREAK AND ASSOCIATED SHORTWAVE
ENERGY WILL FURTHER AMPLIFY THE SHORTWAVE TROUGH DURING THE
PERIOD.  STRENGTHENING PRE-TROUGH QG FORCING -- ENHANCED FROM THE
LEFT-EXIT REGION OF THE UPPER LEVEL JET STREAK NUDGING INTO THE
TROUGH BASE -- AND ASSOCIATED PRE-FRONTAL DEEPENING SOUTHERLY
FLOW/WARM AIR ADVECTION/MOISTURE TRANSPORT (WITH PWS INCREASING TO
AROUND 2 SIGMAS ABOVE THE MEAN FOR THE TIME OF YEAR) WILL CONTINUE
TO SUPPORT LINEAR MULTICELL CONVECTION ALONG/AHEAD OF THE SURFACE
COLD FRONT.  SUFFICIENT DEEP-LAYER INSTABILITY (MUCAPES ~1000
J/KG) ALONG WITH SHARP WIND CONVERGENCE ASSOCIATED WITH THE HEIGHT
FALLS WILL MAKE FOR A RATHER PROGRESSIVE PRECIPITATION
SHIELD...AND AS SUCH AREAL-AVERAGE AMOUNTS WILL BE CAPPED AROUND
1-1.5 INCHES.

LATE THIS AFTERNOON AND EARLY THIS EVENING, THERE IS A BRIEF
WINDOW WHEN THE LOW-LEVEL INFLOW (WHICH IS SUFFICIENT FOR THE WET
MULTICELL ENVIRONMENT) CONSPIRES WITH A SLOWING SURFACE FRONT AND
INCREASED INSTABILITY DUE TO DAYTIME HEATING TO ELEVATE FLASH
FLOOD CONCERNS.  HOWEVER, SOME DRY AIR IN THE LOW-LEVELS SEEN IN
REGIONAL SOUNDINGS SHOULD ALLOW THE CONVECTION TO REMAIN FORWARD
PROPAGATING, TO THE EAST-SOUTHEAST AT 20+ KTS PER THE 06Z GFS.  IF
CONVECTION GETS TOO FAR REMOVED FROM THE FRONTAL BOUNDARY, A NEW
LINE OF STORMS ALONG THE FRONT ITSELF COULD LEAD TO A SECOND
CONVECTIVE ROUND, INCREASING THE RISK OF FLASH FLOODING.  THE
AVAILABLE GUIDANCE LED TO GOOD CONTINUITY WITH THE 12Z WPC QPF,
THOUGH THE ADVANCE OF THE PRECIPITATION INTO NEW ENGLAND WAS
SLOWED SLIGHTLY.


FLORIDA
~~~~~~~

BROAD UPPER LEVEL TROUGH WITH CONVECTIVE FRONTAL WAVES -- A
WEAKENING ONE IN THE EASTERN GULF OF MEXICO AND A STRENGTHENING
COASTAL LOW OFFSHORE NORTHEAST FL/GA -- WILL FOCUS 25-35 KTS OF
LOW-LEVEL INFLOW ACROSS SOUTH-CENTRAL FL AND CLOSE TO THE
COASTLINE OF THE SOUTHEAST US FROM THE GA COAST NORTHEAST THROUGH
THE COAST OF THE CAROLINAS, WITH COASTAL NC EXPECTED TO RECEIVE
THE MOST RAINFALL.  PWS OF 2" ALONG WITH EXPECTED BOUNDARY LAYER
MOISTURE CONVERGENCE IN BOTH REGIONS COULD FOCUS WET MULTICELLS
WITH HIGH HOURLY RAIN RATES OF UP TO 2.5", GIVEN ENOUGH
INSTABILITY IS PRESENT.  LOCALIZED AMOUNTS OF 3-5" WILL BE
POSSIBLE. GIVEN THE ANTECEDENT HIGH FFG VALUES ACROSS FL, ANY
SHORT-TERM RUNOFF ISSUES ARE LIKELY TO BE ISOLATED AT MOST.
UNCERTAINTY REMAINS WITH THE QPF EXPECTED NEAR THE COAST OF GA AND
THE CAROLINAS, THOUGH NC APPEARS TO BE MOST FAVORED FOR ANY HEAVY
RAINS.  THE MOST RECENT QPF TRENDED SLIGHTLY WETTER ACROSS EASTERN
NC AND SHIFTED THE FL MAXIMUM SOUTHWARD PER THE AVAILABLE MODEL
GUIDANCE AND RECENT RADAR/SATELLITE TRENDS.

HURLEY

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

24HR QP VT 22/12Z
 0.01 236035 228033 229046 245064 261082 268090 277099 287105
      291109 290114 292117 293119 297120 302121 305119 310116
      314117 319117 325114 333115 340124 349130 358139 364150
      369163 372170 373175 374177 371178 365179 364182 365186
      382206 394212 404221 407225 409230 413227 417222 421214
      421205 419190 418186 419181 424177 423171 425163 426153
      426144 427143 429145 431147 435149 438154 439156 442156
      444155 445151 446143 448139 449133 448122 451115 452103
      452092 451088 449087 446088 443087 439082 449072 444068
      439066 435065 432063 424062 420061 418059 411052 408049
      400046 393044 387040 380031 377024 374019 370014 369010
      369005 368997 367990 364976 361937 361933 359930 357925
      355923 353925 350927 350931 348934 348939 348949 348968
      347972 345971 343965 343962 340962 336956 330958 329962
      323962 321966 321977 321984 322990 322993 320994 312994
      306992 300990 295987 293986 292982 290976 291965 292958
      292956 289955 281955 274958 271958 268955 263952 256950
      251950 245954 240956 236961 234967 233974 234980 234988
      234997 238001 247008 259016 268025 276032 281035 282040
      281046 277049 270051 260047 249041 236035
 0.01 524261 517258 512258 500255 492244 491242 489243 487249
      490255 490258 488260 478263 468266 459267 447270 438274
      428278 420283 418286 418289 421295 425299 429301 435302
      440301 450299 470294 490289 502290 509292 513292
 0.01 502679 501672 499669 498664 495661 490659 484658 479661
      475663 472662 470660 468656 466646 465644 463643 458647
      450654 439662 435664 434666 431670 415678 408681 404685
      396694 391698 386704 381708 378714 374724 371730 370732
      372733 370737 364741 351749 345753 341758 340760 341764
      345768 354767 360764 367762 373759 382751 387748 393746
      399749 404748 419742 416748 413754 409758 404762 398767
      394772 388782 382791 378796 374801 366810 356822 353822
      352819 350817 346818 341818 340820 334826 330837 324863
      323870 322877 320892 320902 319907 319912 319931 319948
      319952 322954 327954 327951 335945 340936 345934 346927
      350912 353904 354900 359899 362895 365887 376862 378857
      380849 386840 395832 404822 407826 408831 409837 411840
      414846 419850 424865 428881 431900 433907 437909 441912
      445916 450919 455920 464921 467922 471922 469917 465911
      462905 459902 458896 457888 456878 458845 459838 460828
      461818 463812 470776 481750 492725 496712 498696 502679
 0.01 459222 458219 454217 447217 439215 436218 433218 426219
      423221 424224 426228 429230 433230 436228 438226 442226
      449226 454227 456225 459222
 0.01 303814 302808 300806 293804 288801 285799 284795 277792
      270791 261792 255795 248798 243804 240810 240817 240823
      242826 243831 241834 235846 230861 229870 229878 230889
      230894 231899 231903 231899 233894 236902 240908 248907
      252903 257897 259889 264876 270862 272859 275857 278851
      280843 285838 288832 289823 290818 291814 295815 303814
 0.01 233916 233914 233912 233910 231910 231912 231914 231916
      233916 233916
 0.25 522265 517265 514263 511261 509262 506266 498271 489272
      480273 473277 469283 470285 473286 482283 491282 501284
      511285 516285
 0.25 495683 496678 494673 490670 486669 482673 476679 469689
      463698 456707 448713 442721 438725 436730 435737 433742
      423758 417769 411777 404784 401788 396790 391793 387797
      380804 377807 376813 376816 378818 384816 400802 403799
      406797 408798 411801 413806 416812 419816 424827 427831
      432832 435830 438825 442813 447802 451792 456784 467764
      477746 482735 487724 490713 492701 495683
 0.25 437112 438102 438098 436094 428089 424090 421095 417098
      413094 409086 412080 415077 416071 415066 412061 409058
      404055 395053 389053 384055 381056 377056 377054 376049
      374047 371043 366036 361034 359029 349011 345005 343998
      342995 340993 338995 337999 335005 332010 322013 310013
      300015 297014 293012 285006 275998 271995 269990 255976
      248974 252971 253968 252965 249961 245961 243962 240964
      238969 239992 241997 244000 253006 267017 276021 281023
      288024 299025 302030 303036 300040 300044 311049 326060
      331062 336063 339064 339066 337068 333068 326068 319069
      316069 311066 306066 305067 305071 309076 307080 303080
      301079 298079 295082 296086 300095 304098 306104 310107
      314108 318108 327105 332104 336101 344092 347090 352088
      360087 364088 369091 379096 385099 385108 384111 381111
      375111 372127 372131 374132 378132 380132 383134 382140
      382144 385148 390156 392161 391165 390169 394175 399176
      404174 418159 418145 417141 414138 410135 409130 411127
      418123 431119 437112
 0.25 425684 421683 416685 409689 396699 390706 386712 384716
      385721 387722 386726 381732 375737 369743 367747 369750
      372749 377746 382742 391729 401716 404707 409701 420689
      425684
 0.25 368833 368830 367827 362829 357836 353844 349851 345860
      344869 348871 352870 355866 357861 360852 363845 367836
      368833
 0.25 286083 286078 283076 280074 269067 259061 250055 241048
      237044 236048 243056 251064 260071 268078 277084 282084
      286083
 0.25 281817 278808 279804 277800 269797 263797 259799 252804
      247810 247815 251817 252821 253826 252837 248844 245852
      242861 241866 242872 245875 248877 254875 257872 260866
      265857 270851 277834 279825 281817
 0.50 521269 518268 516270 514266 510265 509270 508272 506272
      502273 499275 495275 495278 496279 501281 506282 509282
      513282 516282
 0.50 492682 491679 489678 484680 478683 475687 467697 460706
      446726 442740 436749 428759 427765 428767 431767 435768
      436771 439775 438789 439792 442791 446787 450783 453778
      459766 465756 475732 481720 486709 490695 492688 492682
 0.50 412692 411692 409692 408693 410694 411693 412692
 0.50 409695 406694 403697 401698 399700 397702 395703 393706
      391709 389711 393712 394710 397707 399706 400704 403701
      405699 407698 409695
 0.50 410112 411105 409098 406097 404100 400104 397106 393111
      389114 387116 388118 390119 395118 401117 406116 410112
 0.50 408072 409068 408066 404063 400060 395059 392062 387064
      383067 381069 379067 374065 371067 369070 365072 362078
      364081 366081 377084 386080 389085 393087 397085 400081
      402076 406073 408072
 0.50 368050 364047 360047 357047 356042 356035 354031 351022
      349017 347014 343006 341001 339005 339017 337021 331022
      326022 321020 319020 314022 312024 313028 315033 315035
      308039 320050 327055 336058 342058 347057 351051 355049
      357052 362053 366052 368050
 0.50 353069 353067 353066 351065 350065 348065 347066 348068
      349069 351070 353069 353069
 0.50 342078 341074 338072 331074 326074 323076 319081 316083
      314086 312089 313093 314097 318098 324095 331094 335092
      337089 339082 342078
 0.50 278011 273004 268998 262992 257985 253982 250981 245982
      242984 241990 242994 248000 256004 264007 271011 276012
      278011
 0.50 273828 272826 269826 267827 263828 261829 260832 260834
      262837 263839 263843 265846 266844 267841 268838 270836
      271834 272830 273828
 0.50 261807 260805 258805 256807 258808 260808 261807
 0.50 262852 263848 259846 257845 256846 254848 252851 251855
      250857 249861 250865 251867 255867 257865 258862 259860
      260858 261854 262852
 1.00 485697 485689 481690 475696 469702 463710 458717 456727
      455733 457735 465730 471724 476717 481708 483705 485699
      485697
 1.00 378078 379076 378074 377073 376072 376071 374070 373071
      371072 370073 369074 368075 369075 370077 372078 374078
      376079 377078 378078
 1.00 348042 347038 344037 339036 334038 328038 322041 321044
      322047 327049 332052 338054 342052 342045 346043 348042
 1.00 258994 257993 256992 255991 255990 253989 253988 251987
      250986 248985 246986 244988 244990 245992 246993 246994
      248995 248996 249996 251997 253997 255997 257996 258994
 1.50 475710 475709 473708 471708 470709 468710 466712 465713
      464715 464716 463718 464720 466721 467720 469719 470719
      471718 472716 472715 473713 473712 475710 475710

$$





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