Quantitative Precipitation Forecast
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000
FXUS04 KWBC 230700
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
259 AM EDT SAT MAY 23 2015


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


DAY 1...

...SOUTHERN PLAINS INTO THE LOWER MISSOURI VALLEY...


...SIGNIFICANT HEAVY RAINFALL EVENT REMAINS ON TRACK ACROSS MUCH
OF THE SOUTHERN PLAINS INTO PORTIONS OF THE MIDWEST...

THE LATEST SYNOPTIC AND MESOSCALE MODEL GUIDANCE CONTINUES TO
SUPPORT A SIGNIFICANT...HIGH-IMPACT MULTI-DAY HEAVY RAIN EVENT
SPANNING THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK...BEGINNING
IN EARNEST DURING THE LATTER HALF OF THE DAY 1 PERIOD (SATURDAY
AFTERNOON INTO SUNDAY MORNING)...HIGHLIGHTED BY THE EXPECTATION OF
A LARGE SCALE...SLOW MOVING NOCTURNAL QLCS THIS EVENING AND
OVERNIGHT. CONSIDERING THE ANTECEDENT SATURATED SOILS AND LOW FFG
ON BOTH SIDES OF THE RED RIVER ACROSS SOUTHERN-CENTRAL OK AND
NORTHERN TX...THE POTENTIAL FOR ADDITIONAL FLASH FLOODING OVER
THESE AREAS WILL BE ENHANCED.

DURING THE DAY 1 PERIOD...THE MODELS ARE IN REASONABLY GOOD
AGREEMENT WITH THE MASS FIELDS...AS THE MAIN (BROAD) UPPER LOW
PIVOTS SLOWLY ACROSS THE 4 CORNERS REGION AND CENTRAL ROCKIES. AS
THE NEXT SUBTROPICAL JET STREAK AND ASSOCIATED SHORTWAVE ENERGY
TRAVERSES THE BASE OF THE LONGWAVE TROUGH...THE ENSUING UPSTREAM
HEIGHT FALLS WILL INCREASE THE BROAD-SCALE UPPER DIFFLUENCE
ACROSS THE SOUTHERN PLAINS NORTHEAST INTO THE MIDWEST AS THE
TROUGH-RIDGE ORIENTATION AMPLIFIES (UPPER TROUGH BECOMES MORE
NEGATIVELY TILTED). FROM A DYNAMICAL STANDPOINT...THE LARGE SCALE
UPPER DIVERGENCE WILL INCREASE SUBSTANTIALLY ALONG THE STREAM OF
THE BACKED SW-S UPPER LEVEL FLOW BETWEEN THE TROUGH-RIDGE AXES.
MEANWHILE...INCREASE S-N UPPER CONFLUENCE EAST OF THE UPPER TROUGH
WILL INDUCE AN ANOMALOUS 90-100 KT SOUTHERLY 250 MB JET STREAK
ACROSS THE SOUTHERN-CENTRAL HIGH PLAINS...ONE WHICH BY LATE IN THE
PERIOD WOULD PROVIDE AN ADDITIONAL BOOST TO THE ALREADY ROBUST
UPPER LEVEL DIVERGENCE AND DEEP-LAYER ASCENT WITHIN ITS RIGHT
ENTRANCE REGION ACROSS THE SOUTHERN PLAINS.

THE ANOMALOUS COOL SEASON DYNAMICAL SETUP WILL COUPLE WITH THE
EQUALLY-ROBUST WARM SEASON THERMODYNAMIC PROFILE IN GENERATING
WIDESPREAD HEAVY RAIN TO THIS REGION...PARTICULARLY LATE TODAY
THROUGH EARLY SUN MORNING AS THE MESOSCALE SIMULATED REFLECTIVITY
GUIDANCE SUGGESTS MULTIPLE ROUNDS OF CLUSTERED CONVECTION PRIOR TO
THE ONSET OF ONE MAIN (SIGNIFICANT) QLCS AFTER 00Z. THE
STRENGTHENING LOW LEVEL INFLOW (45-50 KT SOUTHERLY LLJ ~850 MB)
AND ANOMALOUS 850-700 MB MOISTURE TRANSPORT FROM THE WESTERN GULF
WILL BOOST PW VALUES BETWEEN 1.75-2.00+ INCHES...OR 2-2.5 STANDARD
DEVIATIONS ABOVE THE NORM PER THE SREF/GEFS ENSEMBLES. MODERATE
DEEP-LAYER INSTABILITY (MUCAPES 1000-2000 J/KG) WILL BE IN PLACE
THIS EVENING AND OVERNIGHT ACROSS THE SOUTHERN PLAINS...SOUTH OF
THE SURFACE WARM FRONT WHICH WILL LIFT NORTH INTO THE CENTRAL
PLAINS BY 12Z SUN.

THE MAIN CONCERN FOR THE OVERNIGHT PERIOD...BOTH IN TERMS OF QPF
AND THE AREAL-EXTENT OF THE ELEVATED EXCESSIVE RAINFALL
POTENTIAL...WILL BE HOW PROGRESSIVE THE DEVELOPING QLCS WILL BE
LATE IN THE PERIOD. THE AFOREMENTIONED LLJ WILL BECOME NEARLY
PARALLEL AND OF THE SAME MAGNITUDE (IF NOT HIGHER) THAN THE MEAN
850-300 MB WIND ACROSS NORTH TX INTO OK AND KANSAS... THEREBY
LEADING TO INCREASING UPWIND PROPAGATION AND LIGHT (IN SOME AREAS
EASTERLY) CORFIDI VECTORS. THIS WILL LIKELY LEAD TO A SLOW
EASTWARD PROGRESSION OF THE CONVECTION...OR AT THE VERY LEAST
MULTIPLE LINE SEGMENTS LIFTING NNE. HOWEVER...ACROSS CENTRAL AND
SOUTHERN TEXAS...MORE DIRECTIONAL SHEAR IS NOTED BETWEEN THE LOW
LEVEL INFLOW AND MEAN WIND...WITH THE LOW LEVEL INFLOW MARKEDLY
HIGHER THAN THE MEAN FLOW. THIS IS ALLOWING FOR A MORE SIGNIFICANT
SOUTHEASTERLY MBE OR CORFIDI VECTOR (15-20+ KTS)...WHICH WOULD
EXPLAIN WHY MULTIPLE HIGH RESOLUTION MODELS (NAM
CONEST...WRF-ARW...WRF-NMMB...NSSL-WRF) BRING HEAVIER RAINFALL
AMOUNTS INTO THE CRP-VIC CORRIDOR OF SOUTHEAST TX (THOUGH NOT ALL
THE WAY TO BRO AND THE LOWER RGV). FOR NOW...AS AN EFFORT TO
MAINTAIN CONTINUITY FROM THE PREVIOUS FORECAST AND REMAIN IN LINE
WITH THE LATEST GLOBAL GUIDANCE/TRENDS...WPC OPTED TO KEEP THE
LOWER DETERMINISTIC QPF AMOUNTS ALONG THE TX GULF COAST...WHILE AT
THE SAME TIME EXTENDING THE SLIGHT RISK FOR EXCESSIVE RAINFALL
INTO THAT SAME AREA.


...CENTRAL TO NORTH CENTRAL PLAINS...

THE INITIAL MID LEVEL SHORTWAVE LIFTING NORTHEAST FROM NORTHERN
NEBRASKA ACROSS SD CURRENTLY WILL CONTINUE TO WEAKEN AS IT MOVES
INTO NORTH DAKOTA TODAY. LIGHT TO MODERATE RAINFALL AMOUNTS ARE
EXPECTED. ADDITIONAL LOW LEVEL CONVERGENCE AND ADDITIONAL SHOWERS
DEVELOP NEAR THE CIRCULATION CENTER IN EASTER WY TONIGHT AND
EXTENDING ALONG THE TRAILING TROUGH AXIS INTO NORTHEAST CO.

THE RETURN SOUTHERLY FLOW AND STRONG 850-700 MB MOISTURE FLUXES
AND INCREASING PRECIPITABLE WATER VALUES SUPPORT SHOWERS/STORMS
BREAKING OUT ACROSS KS SAT.  LOCALLY HEAVY DOWNPOURS ARE POSSIBLE
FURTHER SOUTH IN THE STATE.  MANUAL QPF USED A MULTI-MODEL QPF
ALTHOUGH CUT BACK AMOUNTS A LITTLE AS CLUSTERS OF STORMS TO THE
SOUTH IN OK/TX MAY INTERRUPT MOISTURE TRANSPORT INTO THE STATE.


...GREAT BASIN...

A REGION OF ABOVE AVERAGE PW VALUES WILL DRIFT EAST INTO
NV/UT/ADJACENT SOUTHERN ID WITH STANDARDIZED ANOMALIES OF 1-2 STD
DEVIATIONS ABOVE NORMAL.  SCATTERED TO LOCALLY NUMEROUS SHOWER
ACTIVITY IS LIKELY AGAIN IN THIS ABOVE AVERAGE PW AXIS WITH 700 MB
VERTICAL VELOCITY MAXIMA ROTATING AROUND THE BROAD CIRCULATION
LEADING TO A RAINFALL MAXIMA IN THAT REGION. THIS COINCIDES WITH A
MAX REGION OF UPPER DIFFLUENCE.  ELSEWHERE...MAXIMA IN THE RANGES
OF NORTHEAST OR/SOUTHERN ID/NORTHWEST WY/NORTHERN NV/NORTHERN UT
COINCIDE WHERE ASCENT IS AUGMENTED BY UPSLOPE FLOW.  LOCALIZED
HEAVY RAIN ARE POSSIBLE WHERE CELLS MOVE SLOWLY.  MANUAL QPF USED
A MULTI-MODEL BLEND...WHICH MAINTAINED GOOD CONTINUITY FROM THE
PREVIOUS WPC FORECAST.

HURLEY

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

24HR QP VT 24/12Z
 0.01 523256 525241 528226 528218 526213 520205 518195 517190
      515187 497182 492181 489183 485187 483191 478198 474200
      469197 467193 465187 463177 463173 465169 467165 470160
      473156 486142 490129 488119 487115 487107 487096 480092
      476089 474084 473077 472073 471069 472065 474064 478059
      478053 479035 475014 469989 468983 467975 465962 464957
      461950 457942 452935 449925 447921 447916 443906 434889
      430883 426881 421881 417883 414887 407896 405900 401903
      392907 383911 376902 373898 369896 365898 365902 362912
      355911 352910 347910 339914 332918 324915 319911 313904
      309879 306871 301861 296854 294847 293845 292841 294822
      293818 292815 293812 298811 299808 297798 293789 295784
      298781 299779 299775 298771 294769 289768 283769 280773
      278781 274787 273784 271785 267788 263794 261797 258794
      254793 251798 252804 250810 245811 242815 242818 245819
      247822 250823 251833 255841 264844 267845 273846 285844
      289847 292852 294857 295863 295866 291868 282864 277863
      280868 281873 283879 283885 285891 284896 284903 282908
      281912 280917 281921 282925 285928 286933 288938 285942
      280943 277945 270949 261953 254956 246960 239965 237971
      237978 237981 239981 239984 237985 235985 234988 233992
      231997 232003 235013 236017 239021 250028 256035 259037
      261043 265064 265070 269073 272075 278080 280080 281077
      280072 282066 297061 314052 322044 327038 331036 336038
      343041 350045 354047 359048 362048 363051 360056 357064
      359068 357072 353084 351105 349109 348117 349122 351128
      356136 359140 360143 359147 357151 357158 361166 361170
      358174 357180 358185 368197 374203 382209 391215 394219
      390223 389224 390229 395231 399230 402229 407230 412230
      415227 418223 422222 430224
 0.01 430224 435222 438221 441222 451225 461228 467230 471228
      480229 483228 485230 488235 491239 493243 497247 500253
      505260 509257 512253 516252 520258 523256
 0.01 527949 526923 523906 521894 519886 514869 512859 509851
      505834 500813 495797 493793 492789 491785 490779 488777
      488773 486769 484764 479747 473730 473725 473720 472713
      470711 466709 464707 462701 474675 476668 479660 478654
      477650 472648 463639 449639 442643 438649 436653 437657
      440663 442664 443667 443673 443682 442692 446697 448701
      448705 446715 447722 447727 450730 452738 454740 455743
      455749 460766 462785 464790 466795 467801 472821 474827
      477832 480836 481842 483852 484873 485885 488894 492899
      495906 498914 500918 500924 504941 512955 515960 522961
      525960 526956 527949
 0.01 468075 467073 465073 464075 463075 462076 461077 461078
      463079 465079 466078 467077 468075
 0.01 336174 337172 335171 334169 332169 330168 328168 326168
      325167 326170 328170 329172 331173 333173 335174 336174
      336174
 0.25 471115 472110 472105 471101 468098 456092 452088 451082
      450072 449066 448057 448053 450050 453044 456035 458027
      460018 460011 458003 453986 450978 447973 440966 436963
      433954 433944 432935 424924 422918 417914 412915 407917
      394923 382929 370932 364933 357933 345932 338934 334940
      331944 325947 318949 312951 286960 277964 272968 271974
      269981 266986 261991 255995 244999 242004 240012 244017
      250020 256023 260027 268033 276041 282043 289043 296041
      304040 314034 324029 336023 342021 347023 352025 359026
      366026 372024 389009 394009 397011 397015 395021 389026
      387032 388041 392048 394053 393061 391066 388072 388076
      390077 396081 399085 405091 408096 407102 404109 400115
      399117 399122 399130 396131 392132 388130 387127 389120
      386116 382110 380106 379099 380090 383085 387077 385075
      382074 379072 375073 370077 364087 362093 361098 361104
      360121 362127 365131 371141 375147 377153 381157 384162
      390161 392160 396161 398163 399168 399172 401176 404178
      407178 413175 419162 423159 426154 427145 432140 441109
      445105 450105 454109 459116 462118 466118 471115
 0.25 424100 423098 422095 420094 419095 417097 416097 415099
      416102 418102 420103 421104 422103 423101 424100
 0.25 393198 392195 390195 389197 389198 390199 391200 392200
      393198 393198
 0.25 388194 388191 385189 382186 383184 383181 381179 378176
      376176 372177 368180 369183 372186 374189 378192 383193
      388194
 0.25 272822 272821 271820 270819 268819 267821 267823 269824
      270825 272824 272822
 0.50 449015 449009 447005 441999 436994 434991 431993 427994
      425999 423003 419006 416006 413003 410996 407994 408991
      410992 413993 415992 419989 420980 421970 422958 425948
      425942 423937 417933 414930 408929 398930 384934 376938
      367941 357943 350945 343948 337954 332958 325962 316964
      306965 287966 283967 280970 279978 277984 271990 265994
      260001 255005 251006 251011 253014 256017 262023 268027
      270028 276028 286029 290031 296032 303030 311028 320025
      327021 333018 338014 347015 351018 357019 364018 369018
      372016 381999 387997 391996 395995 398991 402993 403997
      402003 402011 400021 395029 394035 395039 400043 404051
      400062 400068 402073 405079 408077 413077 418078 422076
      429072 433072 435075 438071 437068 436057 436045 439041
      443040 446037 447031 449015
 0.50 378133 379130 380128 380126 379124 378123 377123 376123
      375123 374125 373127 373129 374132 376133 378133 378133
 1.00 427056 427051 427049 425045 424044 420042 419043 417047
      416050 416054 417057 418060 420062 421062 425060 426058
      427056
 1.00 419039 419037 417037 417036 415035 414034 413033 412033
      410033 409035 410036 412036 413038 414038 415040 416041
      417041 418041 419040 419039
 1.00 410956 407953 403954 400957 398955 394946 392942 388941
      378943 371946 355953 341960 328969 321973 316975 313973
      308971 302972 294975 288980 284986 280994 278003 273011
      274016 276018 281018 285016 291012 295010 300010 306013
      309016 315017 322014 329009 337008 343008 347010 352011
      356010 360008 362005 366997 371990 377985 388974 393966
      402964 407961 410956
 1.50 388956 388951 386948 382948 374949 368951 357956 346963
      335969 325976 319980 314983 308987 307979 304977 301977
      297979 292984 288989 286997 286002 287006 291007 296005
      303003 307007 314011 321009 325004 331002 339002 344002
      350006 355007 360002 363996 366990 369985 373978 377973
      383964 388956
 2.00 383954 373953 364955 357958 350963 335972 323983 317988
      313992 312996 312003 315006 317007 321005 326997 337998
      342998 347998 351001 354002 356001 361994 364985 374970
      379963 383954
 2.00 299987 299984 296985 294987 292989 291991 290995 289997
      289002 291003 295003 297001 298998 298994 299989 299987
 3.00 372963 372959 370958 366958 361961 357964 350969 341974
      333980 330984 328987 330990 334992 340991 345990 349987
      353978 357974 361971 370965 372963
 4.00 347980 346978 344977 343977 341978 339979 338980 337982
      337983 337984 339985 341985 342984 344983 345982 346981
      347980

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