Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 220700
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
259 AM EDT MON SEP 22 2014


PRELIM DAY 1 QPF DISCUSSION
VALID SEP 22/1200 UTC THRU SEP 23/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR




DAY 1...

GREAT BASIN TO THE CENTRAL ROCKIES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
AN AREA OF HIGHLY ANOMALOUS PRECIPITABLE WATER VALUES (PWS) --
3.5-4.0 STANDARD DEVIATIONS ABOVE NORMAL/NEAR THE 99TH PERCENTILE
FOR LATE SEPTEMBER PER THE RAP/SREF/GEFS GUIDANCE (1"+) -- WILL
CONTINUE TO PULL NORTHEAST NEAR AND AHEAD OF THE MID- TO
UPPER-LEVEL LOW CURRENTLY ACROSS NORTHWEST NV WHICH PROGRESSES
INTO NORTHWEST WY WITH TIME.  LOW-LEVEL INFLOW AT 700 HPA IS
FORECAST BY RECENT RAP/NAM RUNS TO BE IN THE 20-25 KT RANGE ACROSS
SOUTHERN ID, MUCH OF UT, EASTERN NV, SOUTHWEST CO, AND WESTERN WY
WHICH WOULD BE SUFFICIENT TO ORGANIZE CONVECTION ACROSS THE WEST.
SOME DRY AIR IN LOW LEVELS (OUTSIDE OF EASTERN NV WHICH HAS
MOISTENED UP DUE TO RECENT RAINS) PER REGIONAL 12Z SOUNDINGS
SHOULD ALLOW CONVECTION TO REMAIN PROGRESSIVE, THOUGH SOME CELL
TRAINING IS POSSIBLE.  EXPECTATIONS FROM DAYTIME HEATING ALONG
WITH RECENT RAP GUIDANCE INDICATES CAPE VALUES OF 1000+ J/KG IN
POCKETS ACROSS UT AND NV THIS AFTERNOON AND EVENING.  FARTHER
NORTH IN SOUTHERN ID AND WESTERN WY, BUILDING INSTABILITY COULD BE
A PROBLEM DUE TO EXTENSIVE CLOUD COVER WITHIN AN AREA OF
DIFFLUENCE TO THE NORTHEAST OF THE UPPER LOW.  AREAS OF WESTERN CO
COULD SEE SOME LOCALIZED HEAVY RAINFALL THOUGH THUNDERSTORM
ACTIVITY MAY NOT BE AS ORGANIZED.  RAINFALL RATES UP TO 1.5" AN
HOUR ARE SUPPORTED BY THE AVAILABLE MOISTURE, WITH MESOSCALE
GUIDANCE INDICATING LOCAL AMOUNTS OF 2-4" BEING POSSIBLE.  USED A
COMBINATION OF 12Z WPC CONTINUITY AND SEPTEMBER PRISM DATA FOR
PLACEMENT, AND USED THE MOST RECENT GUIDANCE TO LOWER AMOUNTS
ACROSS SOUTHWEST CO WHICH FIT IN BETTER WITH THE 00Z GEFS- AND
CLIMATOLOGY-BASED REFORECAST.


WEST TEXAS INTO NEW MEXICO AND SOUTHEASTERN ARIZONA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A PERSISTENT 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, THOUGH THE LOW-LEVEL FLOW SHIFTS FROM MORE
SOUTHEASTERLY TO MORE SOUTHERLY WITH TIME.  ALSO IN THE MIX ARE
THE REMAINS OF ODILE, WHICH SHOULD OPEN UP INTO AN INVERTED TROUGH
AND DAMPEN OUT AS THE REMNANT TROUGH PROGRESSES NORTHWEST INTO NM,
WITH HEAVY RAINFALL FADING IN ITS WAKE DUE TO A DEVELOPING
SUBSIDENCE INVERSION.  PWS REMAIN BETWEEN 2 AND 3 STANDARD
DEVIATIONS ABOVE NORMAL ACROSS THE AREA FOR LATE SEPTEMBER -- IN
THE 1.75-2" RANGE -- WITH THE WESTWARD EXTENT (SECONDARY PW AXIS)
ACROSS SE ARIZONA/WESTERN NEW MEXICO AIDED BY SOME UPPER-LEVEL
MOISTURE TRANSPORT NORTHEAST OF A WEAKENING T.S. POLO.  AREAL
AVERAGE AMOUNTS RANGE BETWEEN 0.50-1" OVER MUCH OF THE AREA WHICH
FITS IN WELL WITH RECENT GUIDANCE AND IS SLIGHTLY LOWER THAN 12Z
WPC QPF CONTINUITY.  HOWEVER...PER THE AFOREMENTIONED 4KM
GUIDANCE...LOCALIZED AMOUNTS OF 2-5" INCHES ARE ADVERTISED FOR
PORTIONS OF NM, WHICH MAINTAINS A FLASH FLOOD THREAT OVER
SATURATED SOILS.


NORTHEAST
~~~~~~~~~
AN AMPLIFYING NORTHERN STREAM MID/UPPER LEVEL TROUGH WILL PUSH
GRADUALLY EASTWARD ACROSS THE NORTHEAST MONDAY. A MODEST UPTICK
WITH THE DEEP LAYER SOUTHERLY FLOW/MOISTURE TRANSPORT AND
LOW-LEVEL MOISTURE FLUX CONVERGENCE AHEAD OF THE MID/UPPER LEVEL
TROUGH WILL CONTINUE TO FAVOR NUMEROUS-WIDESPREAD COVERAGE OF
PRE-FRONTAL CONVECTION. THERMODYNAMICS DURING THIS PERIOD ARE
MODEST AT BEST HOWEVER...WITH PWS PEAKING NEAR 1.5 INCHES AND
MUCAPES AROUND 500-1000 J/KG. THIS WILL LIMIT SHORT-TERM RAINFALL
RATES AND THUS THE FLASH FLOOD THREAT...DESPITE THE SLOWER
EASTWARD PROGRESSION OF THE UPPER TROUGH AS IT AMPLIFIES.  KEPT
CLOSE TO THE 12Z WPC QPF HERE WHICH RESEMBLED THE MOST RECENT
GUIDANCE AND LINES UP FAIRLY WELL WITH THE LATEST REFORECAST DATA
USING ANALOG EVENTS.


FLORIDA/SOUTHEAST/GULF COAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A FRONTAL ZONE REMAINS ACROSS CENTRAL FL INTO LATE TOMORROW, WHICH
IS EXPECTED TO FOCUS PWS OF 1.75-2 INCHES AND CAUSE SHOWERS AND
THUNDERSTORMS, MAINLY DUE TO DAYTIME HEATING, THOUGH MORE LIMITED
ACTIVITY IS POSSIBLE ALONG THE BOUNDARY OVERNIGHT.  OTHER LIGHTER
ACTIVITY IS EXPECTED TO BREAK OUT ACROSS THE DEEP SOUTH AND
TOWARDS THE LOWER EASTERN SEABOARD AND GULF COASTS AS A SECONDARY
COLD FRONT MOVES IN FROM THE NORTH.  AFTERNOON SEA BREEZE ACTIVITY
SHOULD MAXIMIZE NEAR THE EAST COAST SOUTH OF THE FRONT IN THIS
PATTERN, WITH MORNING ACTIVITY MOST LIKELY IN THE KEYS AND WEST
COAST.  THE GUIDANCE IS SHOWING INCREASING SPREAD IN THIS REGION,
WITH THE 12Z REGIONAL CANADIAN MODEL (NOT SUPPORTED BY ITS
CORRESPONDING GLOBAL RUN) AND 12Z NMM SHIFTING THE MAXIMUM MORE
INTO NORTHERN FL AND MAGNIFYING AMOUNTS.  DOWNPLAYED THIS SCENARIO
FOR NOW AND KEPT CLOSER TO 12Z WPC QPF AND 00Z GEFS- AND
CLIMATOLOGY-BASED REFORECAST WHICH GENERALLY SPLIT THE DIFFERENCE
SEEN IN THE GUIDANCE, WHICH LED TO INCREASED AMOUNTS ACROSS FL AND
DECREASED AMOUNTS ACROSS THE CAROLINAS AND GULF COAST.

ROTH

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

24HR QP VT 23/12Z
 0.01 522264 522258 520253 515244 513239 512233 507225 511216
      513210 516210 517214 518218 521222 526224 528224 529221
      529213 528208 522200 519196 516194 512194 510191 508182
      504176 499171 497169 493167 484163 476164 469168 464171
      461172 456173 454172 454168 454165 456162 456159 455157
      453153 453145 457135 458130 458125 457118 457112 458103
      455095 456064 442026 455015 457009 457001 457995 454991
      448987 445982 444978 444972 443969 440966 436965 432965
      429963 421963 414965 407969 397971 387973 378976 371979
      366981 362984 360987 357992 356996 359000 362003 365005
      370007 370010 367016 362023 356022 341016 329007 321001
      318998 317994 315989 314983 310975 304954 305943 306941
      308939 310941 314939 317935 319925 319915 319910 321907
      326870 330848 332839 335829 338818 341807 345799 350791
      360764 361760 358758 352764 344776 341781 340774 342763
      340750 341746 339744 333744 329747 325757 321765 316772
      313776 310778 302782 292784 283785 274785 268784 260784
      256785 252787 250790 246793 239799 236808 236818 236825
      238832 241835 241838 240840 231843 227845 225849 224857
      226866 227869 226873 227880 232887 234894 239901 242903
      244903 252886 256884 261883 267883 271885 276886 280884
      285875 286872 288876 289889 287911 286921 286931 282968
      282982 284991 286997 288000 296000 296006 298011 303021
      300031 295039 289043 282045 278045 273045 266043 258038
      253032 248028 246026 243025 234026 230026 228028 225054
      229060 235064 241068 246072 251077 255082 260087 265093
      268097 274102 278104 280107 287110
 0.01 287110 303114 311115 320113 326110 333111 336113 338111
      341107 348102 354100 369093 374094 376096 381097 394092
      398091 400091 401094 402098 400102 398106 395109 392111
      392116 390118 390122 393121 399118 403120 405123 409124
      412123 419128 420133 420140 419149 421149 423146 424136
      426133 429135 432140 433151 437159 442160 445162 445169
      446173 444175 442179 438184 437187 434188 430187 429185
      425185 423188 424196 429197 431198 433200 432206 429209
      425212 422220 424225 431227 440227 446226 451225 455226
      459226 460230 439239 435241 432244 428252 427254 428260
      431263 434264 445263 449262 450264 448265 442269 437274
      433280 434285 437288 441289 444288 468284 475282 482282
      489281 497283 502285 506286 508284 517277 521269 522264
 0.01 503197 502194 499193 495194 490190 483193 479195 476194
      474191 470188 461190 465194 469196 479200 484201 487199
      491198 493201 499200 503197
 0.01 494671 493664 491661 486657 482658 475662 466673 458684
      449697 441706 432719 428724 423727 423734 426735 433738
      434741 434745 431751 427752 424750 420747 419748 417752
      419755 423761 425764 424768 429771 433768 438763 444759
      449753 452748 453740 452734 453730 458722 462717 465715
      467713 479704 483699 486693 489688 492681 494671
 0.01 491227 491224 489224 488223 483221 479221 474221 471223
      468225 468228 470229 475230 477230 480234 482236 483235
      486232 490229 491227
 0.01 449087 449085 447082 446080 444078 443078 441077 439079
      439081 440083 441084 442086 444088 445089 447089 449087
 0.01 435088 432074 433059 434050 431048 430049 429053 428058
      428063 421072 417083 413094 412098 412103 416104 420102
      423098 425096 424093 424086 426084 430086 433089 435088
 0.01 424789 423775 420775 418778 413784 411787 407789 403792
      398793 389794 385801 382804 378805 375808 373812 373821
      374828 376830 379832 383832 389831 390828 385827 383824
      383820 384815 387808 390804 396803 400802 403804 409810
      413810 415807 413803 415800 416797 423792 424789
 0.01 230999 236007 241012 246014 253015 258013 262009 263002
      262994 260990 258983 259976 263966 265961 265956 255949
      253947 249947 245949 237957 232967 231967
 0.25 518262 517256 512253 506251 501248 497245 492243 489242
      485242 482244 478248 478251 479254 479258 476265 475267
      477271 479271 489272 494272 499274 503276 507274 513269
      518262
 0.25 488673 487668 485669 483670 481672 479675 477677 475679
      474682 475687 477689 480687 482685 485682 486679 487676
      488673
 0.25 447128 448119 449111 447107 445103 441101 435102 434105
      431109 428110 425115 427118 430120 432118 435117 438118
      441122 439132 437137 438139 441134 443132 447128
 0.25 435999 436994 436989 433983 429979 424977 417977 412978
      404979 400981 391986 385990 382994 381997 382000 387004
      396009 402009 407007 412005 418004 426004 431003 435999
 0.25 226048 229053 234057 244064 258075 266084 274092 279095
      285097 298099 311101 315101 317100 323098 333096 339095
      339089 349082 352077 358073 365070 365074 366076 369079
      372081 376081 381078 385073 389069 394072 400072 405072
      410071 410066 406062 402060 398060 391060 387063 381064
      376063 371062 371057 373055 373050 370043 366039 354036
      346033 342031 338031 334034 326042 321040 316038 312036
      309038 309043 310046 311048 310050 305054 299056 288058
      284058 279059 273062 267062 261061 255059 250055 246053
      238047 231043 228043 226044
 0.25 406023 405021 404019 400017 397017 394018 392018 388019
      386022 388025 391026 395026 397027 400029 403029 405026
      406023
 0.25 396080 396078 395076 394077 393078 394080 395081 396080
 0.25 392055 392053 391052 390050 388050 387052 387054 388056
      390057 391057 391056 392055
 0.25 336802 337792 334785 329785 326790 321800 316811 315818
      313824 311837 311842 313845 316849 317851 319850 321846
      326835 331824 334818 335811 336802
 0.25 308805 306797 304794 301792 297790 289790 273790 267793
      260795 258797 257801 260805 260808 261813 264814 268813
      268816 265818 257818 251818 249821 249824 251834 248841
      241851 237856 234862 235869 236876 238884 240887 245886
      252877 259874 266874 270873 275871 280865 283859 287846
      290841 293834 295828 298823 302819 305814 308805
 0.25 295914 295912 295911 295912 295914 295916 295914
 0.25 231987 235991 240993 246996 249998 253002 254998 252992
      250986 248981 242979 237980 231981 230983
 0.50 505268 506263 506261 503257 502256 499255 497256 494256
      493261 491263 493265 495267 498269 501269 503269 505268
 0.50 429992 428988 426985 419982 410983 403985 396988 391991
      389993 390997 392999 395000 399000 405000 411000 419999
      423999 427997 429992
 0.50 375069 375068 373067 372068 373069 374070 375069
 0.50 364054 361048 354049 350050 347050 343045 336045 325046
      320048 320053 320056 318057 312057 308060 307068 306072
      303071 298068 295067 292069 285070 281072 283076 279076
      274078 274080 276080 283082 298083 303082 307079 311076
      316079 320082 324083 328084 334082 338080 341076 344070
      348067 352065 356062 358059 361057 364054
 0.50 333811 334800 331791 326796 323801 320808 318817 315824
      314828 314832 315837 317835 322831 327826 330819 333811
      333811
 0.50 302806 300800 296795 291794 284794 279792 276792 274795
      270798 272801 277803 279806 279810 277815 274820 270823
      262824 258828 256833 254839 251844 245852 238862 239868
      240874 240878 242880 245879 247877 253870 264863 267862
      270863 275865 279860 281853 282847 285842 288837 291831
      294821 301814 302806
 0.50 243990 243988 242986 240984 239984 237984 235983 234985
      235987 237989 238989 239990 240990 242990 243990
 1.00 338056 339054 338052 336052 335051 334051 332050 331050
      329050 327050 327051 326053 326055 327056 328057 330058
      332059 334059 336058 338056 338056
 1.00 330813 330807 329801 325804 323808 321812 320817 319821
      318826 322825 325823 327820 329816 330813
 1.00 295811 296809 295807 295805 294803 294802 292801 290802
      289803 289804 288806 288808 288810 289811 290812 291813
      293812 295812 295811
 1.00 286829 286824 284823 278824 274827 269829 267831 266836
      266841 262846 258849 249857 245861 243865 242867 245869
      250867 259860 269854 273855 276852 278846 282836 286829
 1.50 328809 327807 326807 325807 324809 323810 322812 322814
      321817 323818 325817 326816 326815 327814 328811 328809

$$




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