Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 270719
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
318 AM EDT MON APR 27 2015


PRELIM DAY 1 QPF DISCUSSION
VALID APR 27/1200 UTC THRU APR 28/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1...

....SOUTHERN PLAINS...LOWER MISSISSIPPI VALLEY...AND EASTERN GULF
COAST...

THE CLOSED UPPER LOW CURRENTLY PIVOTING INTO THE SOUTHERN HIGH
PLAINS WILL PUSH SLOWLY EAST TOWARD THE ARKLATEX BY TUE MORNING.
ROBUST FORCING FOR DEEP-LAYER ASCENT WILL CONTINUE OUT AHEAD OF
THE LOW...AS THE DIFFLUENT UPPER LEVEL FLOW AHEAD OF THE LOW
COUPLES WITH THE RIGHT-ENTRANCE REGION FORCING FROM THE UPPER
LEVEL CONFLUENT FLOW ACROSS THE NORTHERN TN/LOWER OH VALLEYS.
MEANWHILE...THE UPPER LOW WILL ALSO HELP TO PULL THE DEEP
SUBTROPICAL MOISTURE PLUME WITH PWS OF 1.5-2.0+ INCHES (2-2.5
STANDARD DEVIATIONS ABOVE NORMAL FOR LATE APRIL) NORTHWARD INTO
EAST TX...MUCH OF LA...AND SOUTHERN MS/AL LATER TODAY...WITH THE
FAVORABLE MOISTURE TRANSPORT AND PW AXIS SHIFTING EASTWARD TO
ALONG THE EASTERN GULF COAST OVERNIGHT INTO TUE AM. LOW-LEVEL
INFLOW AVERAGING 25-35 KTS WILL HELP DRAW IN THE
THERMODYNAMICALLY-RICH AIRMASS ALONG AND NORTH OF THE SURFACE
FRONTAL BNDRY... TAPPING A MODESTLY UNSTABLE AIRMASS WITH MUCAPES
AVERAGING 1500-3000 J/KG ALONG THE GULF COAST. THESE INGREDIENTS
COULD LEAD TO SCATTERED POCKETS OF VERY HEAVY RAIN...WITH SHORT
TERM RAIN RATES OF 2 TO 3 INCHES IN AN HOUR OR TWO. USING A
MULTI-MODEL BLEND (LEANING TOWARD RECENT NSSL WRF GUIDANCE WITH
THE TIMING)...AREAL-AVERAGE QPF ACROSS EASTERN TX EAST-SOUTHEAST
ACROSS MUCH OF LA AND SOUTHERN MA/AL WILL RANGE BETWEEN 1-2+
INCHES THROUGH 12Z TUE...HOWEVER...AS NOTED FROM THE HIGHER
RESOLUTION GUIDANCE THE DYNAMICAL AND THERMODYNAMICAL SIGNAL IS
THERE FOR MUCH HEAVIER (POTENTIALLY EXCESSIVE) AMOUNTS...TO THE
TUNE OF 3-6+ INCHES.

A SLIGHT RISK AREA ALSO EXTENDS BACK THROUGH WESTERN AND CENTRAL
OK ALONG WITH NORTH TX AND THE TX PANHANDLE...WHERE STRONG LIFT
WILL MAINTAIN HEAVIER DOWNPOURS EMBEDDED WITHIN A LARGER SCALE
PRECIPITATION AREA DEVELOPING NORTH OF A CLOSED MID LEVEL CENTER.
ALTHOUGH THE DEEP LAYER ASCENT AND LOW-LEVEL INFLOW WILL FAVOR A
LONG DURATION RAIN EVENT HERE...LESSER INSTABILITY WILL LIKELY
LIMIT SHORT TERM (1-3 HOURLY) RAINFALL RATES...THOUGH GIVEN THE
ALREADY WET ANTECEDENT SOILS AND (THUS) LOWERING OF FLASH FLOOD
GUIDANCE...THE FLASH FLOOD POTENTIAL HERE WILL EXIST MORE IN THE 3
TO 6 HOUR ACCUMULATION OF MODERATE AND LOCALLY HEAVY RAIN OVER ANY
PARTICULARLY FLASHY BASINS.


...CENTRAL/SOUTHERN ROCKIES AND HIGH PLAINS...

LIGHTER PCPN AMOUNTS ARE EXPECTED ALONG THE FAVORABLE MID-LEVEL
DEFORMATION ZONE ALONG THE BACKSIDE OF THE CLOSED LOW... THOUGH
THE CONTINUED DYNAMICAL FORCING...NORTHEASTERLY (UPSLOPE) LOW
LEVEL FLOW...AND ANOMALOUS 850-700 MB MOISTURE TRANSPORT AND PW
WILL LEAD TO ADDITIONAL AREAL-AVERAGE PCPN OF .25 TO .50+ INCH
ACROSS THE EASTERN SLOPES AND FRONT RANGES OF THE SOUTHERN
CO/NORTHERN NM ROCKIES.


HURLEY

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

24HR QP VT 28/12Z
 0.01 521269 521262 521258 518250 513242 511233 507227 503225
      500223 495218 491222 495239 500247 498249 495246 490239
      487237 484237 472236 471239 466238 459236 451237 447237
      444240 438241 432243 429243 425246 421255 420260 420265
      422267 424267 437257 442254 445252 448251 452250 456251
      466254 481260 486263 487267 490276 494283 500288 507289
      510286 512282 521269
 0.01 500643 499634 497628 495624 491622 478626 467631 451642
      442649 434657 427666 421672 415679 410685 407690 405694
      405700 405707 407711 408720 410726 415734 418739 420747
      421751 424754 426757 423761 422766 420771 418776 416781
      415788 416794 415800 415804 413808 414812 416812 420804
      422798 425794 428784 428776 428768 429764 431764 435759
      439762 441760 447752 450748 453743 454737 457732 466713
      471703 478694 479688 478679 476675 475671 478670 484668
      487664 495655 500643
 0.01 515960 515954 513950 513944 514941 514928 508922 508915
      507910 504908 499906 494909 487914 482922 471938 448959
      443966 441974 440979 439985 439992 442994 448996 446005
      445010 444012 440017 430033 429038 428043 425044 419043
      416039 410035 405035 400032 394029 386026 382007 379986
      378969 374951 365930 361922 356915 353909 348903 337891
      329878 322862 317849 315841 313832 313824 308816 306806
      304802 301800 291797 287796 284793 268792 264791 259791
      253796 252798 253801 255805 257806 263806 271807 273809
      274813 274828 274851 273861 272871 272885 272897 273907
      272916 267932 261947 257960 254967 254974 260978 264980
      269981 274980 277979 284975 292971 299965 306969 310973
      311977 312981 312986 309993 308998 307004 311009 312013
      312018 314022 317023 323027 325027 326031 329040 329042
      327044 322044 315043 313045 316050 319053 317057 316058
      321059 326058 333059 338067 338073 341075 343078 339080
      336081 331081 324085 322089 326094 338099 353089 359084
      363082 368082 378087 386089 394089 399083 401079 404077
      412076 418062 421060 421064 422074 423081 425087 428092
      431094 431092 428089 429080 431075 432074 434076 434078
      438076 439074 442072 444073 448076 447073 443070 437066
      436063 439060 443054 447051 450050 457047 463047 468046
      471044 479035 492023 497016 501007 511973 515960
 0.01 455035 455032 454030 452032 450034 449036 448037 447039
      448041 450041 452039 453037 455035
 0.01 410110 410108 410105 409103 409101 408099 406100 406102
      406105 405107 405108 404109 404111 405113 406112 407112
      408111 410110
 0.01 407789 406786 403785 396788 389792 384796 379803 380812
      384813 391808 396805 401800 406794 407789
 0.01 398113 398112 396112 394114 392114 394115 396115 398113
      398113
 0.01 390116 389116 387115 387116 386118 387118 388116 390116
      390116
 0.01 381063 381060 379058 375057 370056 365056 361058 357059
      356061 357064 362063 366062 370060 374062 378063 381063
 0.01 370775 369770 367766 363760 359754 356748 350742 348742
      346745 349754 351762 355769 359775 365778 368777 370775
 0.25 517270 518266 518262 517256 512244 509241 507238 504239
      503244 503252 503256 500256 496252 492250 490254 491260
      496271 501281 506283 509278 512274 516270 517270
 0.25 484648 484643 482640 479640 476643 474645 472647 471650
      470653 471657 473658 476657 479655 481654 483651 484648
 0.25 383051 379046 375041 368033 369015 371004 372997 373990
      373981 371967 365953 361946 357941 344923 337912 328900
      321890 315881 312875 310869 308859 306850 302819 301816
      297813 291816 287818 285822 284829 280855 278871 277890
      277898 278907 279912 282918 290931 292938 290947 289954
      291957 295956 306955 315957 320961 321968 325975 324986
      321991 320996 323003 327008 333010 338015 343019 346024
      347030 347039 349043 352045 357041 361038 365038 366041
      372051 377053 383051
 0.25 378080 379078 379076 378075 376076 376078 376080 377082
      378080
 0.25 270800 269798 268797 266796 265796 264796 262796 260797
      259798 258799 259800 260801 261801 263802 265802 267802
      268801 270800
 0.50 516267 517262 516259 515256 514252 512250 510246 506247
      506250 507253 508256 508259 509262 510266 512268 514269
      516267
 0.50 505279 506274 506271 505268 504265 501262 499259 498258
      495256 493256 493259 494262 495265 497268 498271 499274
      502277 503279 505279
 0.50 367016 368000 369986 369978 368971 365963 363958 351941
      342935 337923 331914 326907 319898 313888 308877 305866
      302853 300845 300836 300830 299825 297821 293823 289829
      286834 285840 284846 282870 281884 280893 281902 282908
      285913 290921 292926 294932 295940 295949 297951 300951
      307950 317953 324955 331954 335954 336956 336960 334962
      331966 332973 337980 337983 335986 337990 340994 343000
      342012 346014 348019 351033 352036 354035 359034 363030
      364026 367016
 0.50 328999 328998 326997 326999 328001 328999
 1.00 515264 515261 514260 513259 512260 512261 513263 514264
      515264
 1.00 503273 503270 501269 501270 502272 502273 503273
 1.00 366996 367988 366981 361969 358964 354960 348961 344965
      341969 344973 347977 348982 345984 343987 344989 348994
      350999 352007 355020 359023 363019 365013 365003 366996
 1.00 329934 328928 327923 321915 310896 306887 303874 299865
      297859 296853 295840 291836 289841 287851 286864 285876
      284883 286889 290898 293911 297921 298927 298935 299942
      301946 312945 316946 321945 325943 328937 329934
 1.50 361016 363011 363005 361996 361991 363987 363982 361978
      357972 355971 352973 352979 351983 348987 348989 349991
      354998 356007 358014 361016
 1.50 321934 321931 319926 315916 311907 306901 301895 299895
      297901 299913 301924 301935 302941 303943 307942 316939
      320939 321934
 1.50 298882 298878 298874 298870 296868 294866 293864 291864
      290868 289870 288874 288877 288881 289883 292885 294886
      296887 297884 298882
 2.00 359998 359996 358994 358996 358998 358999 359998
 2.00 357989 357987 357985 357983 356980 355979 353980 353982
      353985 353986 354987 355988 355989 357991 357989
 2.00 314930 314922 312916 309911 305907 300905 302909 302918
      303924 304933 305939 310937 314932 314930

$$




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