Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 201827
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
227 PM EDT SUN APR 20 2014


PRELIM DAY 1 QPF DISCUSSION
VALID APR 21/0000 UTC THRU APR 22/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1...

...SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY...

THERE ARE A VARIETY OF FORCING MECHANISMS SURROUNDING A SOUTHERN
STREAM TROUGH HERE...BUT THE FORCINGS AT VARYING LEVELS ARE
GENERALLY NOT ACTING TOGETHER OVER THE SAME MESOSCALE REGIONS.
EXPECT DIURNAL THUNDERSTORMS TO BE MOST NUMEROUS THIS AFTERNOON
ALONG A STALLED BOUNDARY IN CO/KS/NE...AND ALSO ALONG THE ELEVATED
TERRAIN OF THE TEXAS PANHANDLE. THE HIGH RESOLUTION MODELS AND
RADAR TRENDS SUGGEST FURTHER ORGANIZATION OF NEAR-SURFACE BASED
CONVECTION IS LIKELY OVER WESTERN NORTH TEXAS WHERE THE DEEPEST
LIFT COINCIDES WITH THE GREATEST INSTABILITY. THOUGH SHEAR IS
SUFFICIENT FOR SOME SEVERE STORMS AND ISOLATED CELLS IN THIS
REGION...PER THE STORM PREDICTION CENTER DAY 1 OUTLOOK...THE
ORGANIZING INFLUENCE OF THE MID LEVEL TROUGH MAY ALLOW FOR UPSCALE
GROWTH INTO AN MCS...WITH SLOW EASTWARD MOVEMENT ALONG AND
ESPECIALLY SOUTH OF THE RED RIVER THIS EVENING. STRONGER CAPPING
ACROSS CENTRAL/SOUTH TEXAS WILL ALLOW BUILD-UP OF A RESERVOIR OF
POTENTIALLY UNSTABLE AIR TO BE FED NORTH-NORTHEAST DURING THE
NIGHT. THIS WILL HELP SUSTAIN ANY ONGOING MCS. BUT DEEP LAYER LIFT
AND ASSOCIATED PRECIPITATION WILL GRADUALLY SHIFT FARTHER NORTH
AND EAST THROUGH OK/AR. MORE HIGHLY ELEVATED MOISTURE AROUND 700
MB IS LIKELY TO YIELD EARLY MORNING SHOWERS FARTHER EAST TOWARD
TN/KY/SE MO.

THE WARM ADVECTION PATTERN FROM EASTERN TX/OK EASTWARD WILL
PERSIST INTO THE DAY MONDAY. LOCAL BANDS OF CONVECTION MAY BE
FOCUSED BY OUTFLOWS SUCH THAT THE FORECAST QUICKLY BECOMES
DEPENDENT ON SMALL SCALE FEATURES...AND THE MODELS OFFER A VARIETY
OF SOLUTIONS. ADDITIONALLY...AREAS FARTHER WEST WILL WARM UP IN
ADVANCE OF A COLD FRONT DIPPING THROUGH KS AND WESTERN OK BY MID
AFTERNOON...AND SCATTERED THUNDERSTORMS SHOULD FORM. THESE
CONCEPTS WERE FAIRLY WELL REPRESENTED IN RECENT RUNS OF THE
WRF-ARW. FOR A LARGE SCALE PERSPECTIVE WE TRIED TO BLEND SOME OF
THE WRF-ARW DETAIL WITH OUR IN-HOUSE ENSEMBLE MEAN AND EVEN THE
ECMWF ENSEMBLE MEAN WHICH TENDED TO CONCENTRATE PRECIPITATION
WITHIN THE WARM ADVECTION REGIME TO THE SOUTH AND STRONGLY FORCED
REGIME OVER THE MIDWEST...WITH A RELATIVE MINIMUM OVER NORTHERN
MISSOURI.


...CENTRAL/NORTHERN PLAINS TO THE MIDWEST/GREAT LAKES...

WITHIN THE ENTRANCE REGION OF AN UPPER JET ASSOCIATED WITH LOW
AMPLITUDE NORTHERN STREAM FLOW...A PERSISTENT ZONE OF 700 MB
CONFLUENCE WILL SUPPORT LIGHT SHOWERS ACROSS THE GREAT LAKES. THIS
PRECIPITATION IS FLANKED BY CONVECTION IN THE MORE UNSTABLE LOW
LEVEL AIR MASS FEEDING UP THROUGH IOWA. ADDITIONAL SURFACE BASED
CONVECTION MAY DEVELOP ALONG A STRENGTHENING SURFACE TROUGH AXIS
OVER WESTERN NEBRASKA...OUT AHEAD OF A STRONGER COLD FRONT PUSHING
INTO THE DAKOTAS THIS EVENING. AN ASSOCIATED UPPER TROUGH WILL
SPREAD VERY STRONG HEIGHT FALLS THROUGH EASTERN NORTH DAKOTA AND
NORTHERN MINNESOTA OVERNIGHT...AND ALTHOUGH MODEL QPFS ARE LIGHT
THERE...NAM FORECAST SOUNDINGS ARE STRONGLY SUGGESTIVE OF MOIST
CONVECTION ROOTED IN THE MID LEVELS. THE AREA EXPECTED OVER
NEBRASKA SHOULD SPILL INTO EASTERN SOUTH DAKOTA WHILE PERHAPS
WEAKENING AFTER DARK. ELSEWHERE FORCING SHOULD BE SUFFICIENT TO
SUSTAIN ACTIVITY...WITH SOME MERGER OF THE PRECIPITATION AREAS
OCCURRING OVER THE GREAT LAKES ON MONDAY. MODELS WERE FAIRLY
SIMILAR HERE...WITH OUR MAIN ADJUSTMENTS BEING TO EMPHASIZE
GREATER COVERAGE OF LIGHT AMOUNTS OVER ND/MN...AND TO DEPICT THE
EXPECTED EVENING ACTIVITY IN NE/SD BASED ON THE HRRR AND WRF NMM
WITH SUPPORT FROM THE CANADIAN GEM REGIONAL MODEL.


...PACIFIC NORTHWEST...

A RATHER WELL DEFINED CYCLONE...WITH 12-HOUR 500 MB HEIGHT FALLS
ON THE ORDER OF 60 METERS...WILL BLEED INTO THIS REGION THROUGH
00Z TUESDAY. DESPITE THIS...THE FORECAST MODELS ARE RELATIVELY DRY
THROUGH THAT TIME. THEY INCREASE PRECIPITATION IN EARNEST ON DAY
2. THE SYSTEM DOES NOT HAVE A SUB-TROPICAL MOISTURE
CONNECTION...AND FLOW AT ALL LEVELS IS MORE SOUTHERLY THAN
WESTERLY UNTIL THE POST-FRONTAL REGIME KICKS IN MONDAY NIGHT.
GIVEN THE HEIGHT FALLS AND STRONG WIND FIELDS THAT WILL CONTRIBUTE
TO UPSLOPE ENHANCEMENT ALONG SOUTH FACING SLOPES...WE LEANED
TOWARD THE SLIGHTLY HEAVIER GFS AND UKMET FOR DAY 1...BUT STILL
CAME UP WITH LITTLE MORE THAN A TENTH TO A QUARTER INCH EXCEPT FOR
HEAVIER VALUES IN THE OLYMPIC RANGE.

BURKE

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

24HR QP VT 22/00Z
 0.01 528196 528188 527185 525179 523176 521170 519167 517169
      518175 519180 516185 516187 518192 523193 526196 528196
 0.01 510257 511249 510244 509236 508230 506226 502218 501214
      498210 493204 489203 486203 478204 471208 466212 460214
      453215 444217 439216 437218 430221 423222 427230 425234
      422235 417234 413231 412226 413219 410218 408220 407225
      404228 405233 405236 403237 397241 391246 390251 390254
      390260 392263 400268 410271 417271 431268 435266 439267
      446268 454268 462266 476266 484265 493267 499267 504266
      508262 510257
 0.01 496994 508994 523979 529949 525919 521905 517895 516883
      513869 501858 486860 477864 466861 466829 464810 454788
      449778 444784 435808 431823 426834 423839 418844 411853
      403861 391866 388866 387864 384858 378848 374846 370846
      367851 364856 361862 359869 355879 345888 334893 326900
      326911 330916 331923 332932 330940 325947 319957 314973
      313975 313981 314987 314991 318995 323993 330994 335002
      339012 343015 350017 357017 363018 369022 375024 382023
      386019 389014 392008 396997 402989 409980 412975 417971
      421968 425964 432954 434952 436953 436958 435962 429973
      427979 425985 424991 421996 417011 416013 416018 418020
      423015 427010 434003 442993 446989 451987 455983 458979
      459973 460965 460946 460941 463936 466937 466940 466947
      467955 469959 471960 473962 473968 472976 474982 477987
      489988 496994
 0.01 504187 506179 506171 504168 501164 498166 495169 493173
      491178 492183 493189 495194 496193 500191 502189 504187
 0.01 484689 483679 479673 479667 476666 473667 463675 461683
      458689 450701 442711 441714 442716 449714 459724 463722
      466722 468724 471723 473720 477714 480709 482701 484689
 0.01 446761 446756 445751 443749 441749 440750 438753 436756
      435758 435763 436768 438770 440770 443769 445766 445764
      446761
 0.01 439153 440151 440149 440148 439146 438146 438148 436150
      438153 439154 439153
 0.01 422159 422156 420152 420149 421146 423143 423141 422140
      419140 417142 416144 414148 414153 415156 416159 417162
      420161 422159
 0.01 418062 414058 409055 404052 397052 395053 394057 397060
      400060 400062 398068 392080 386081 383079 384084 388088
      390095 392091 395087 397080 401075 406073 411072 415066
      418062
 0.01 407107 408105 408103 409101 408098 406098 406100 406102
      405105 404106 403107 402108 400108 400111 401111 403112
      403111 405110 405109 407108 407107
 0.01 396113 396112 394112 392112 390114 389114 387115 387116
      386118 388118 390116 392115 394115 394114 396113 396113
 0.01 392075 392073 392071 391068 389066 389065 389066 387068
      387070 388072 389073 390075 392075 392075
 0.01 394048 394040 393036 393029 391032 391038 393042 388045
      385047 382047 377045 375041 369039 365038 361039 357041
      354044 351048 346050 338053 332053 328055 326057 330060
      340060 344061 350062 356062 359066 362069 367070 370071
      372073 375076 377078 378071 377061 377055 383054 386054
      389051 392048 394048
 0.01 385111 386109 386108 384108 382108 382110 384111 385111
      385111
 0.01 358763 367754 371744 371735 368727 365724 360722 353726
      348733 345741 343750 343757 342761 345765 349766 354765
      358763
 0.01 343100 342096 339093 338089 336084 334081 328081 328083
      332087 334090 336094 338098 341100 343100
 0.01 305034 305027 304023 301019 299018 296019 290012 286008
      282007 278009 276013 276015 273017 269014 263008 258000
      252993 248991 244992 241989 236989 232991 230995 231000
      235002 240004 243008 257018 263025 266027 272030 276031
      281031 290028 293029 293031 295035 298039 301036 305034
 0.25 505247 504239 502230 498226 494230 491237 485238 478236
      475237 473239 464246 458249 453253 451255 451259 456261
      462260 469258 481259 487258 493256 502250 505247
 0.25 502903 503898 502893 501889 500888 496888 495890 493892
      492895 490899 493900 495901 497905 499907 501906 502903
 0.25 454842 455832 453824 450819 449812 446804 443808 442816
      442825 442830 444832 444836 443844 441851 434859 428870
      423881 418893 419903 420909 418926 415940 415945 416948
      419948 421946 429938 432933 435927 442899 447888 450882
      452874 452866 452858 454842
 0.25 428255 429253 428250 424250 422251 419251 417252 415253
      412254 410256 410260 414261 415260 419259 421258 423257
      425256 428255
 0.25 403926 404924 404922 403921 402919 401918 400920 398922
      397924 396927 397929 397931 398933 400933 401931 402931
      402929 403927 403926
 0.25 399968 399963 398961 395960 393961 391960 390963 390968
      390972 390977 391979 393979 394977 396974 398970 399968
 0.25 396945 396941 395940 393941 391943 389946 388949 388954
      389956 391956 393957 394954 395952 396947 396945
 0.25 381938 382933 380929 377925 370922 366918 364908 364899
      363896 361894 358894 356896 353904 352907 353912 353918
      352921 348922 343926 339932 337937 334944 321967 318975
      320981 321984 323986 325985 328984 332984 338985 341987
      342990 345005 348007 351007 353005 354001 354991 350985
      349981 349976 352970 353962 355954 357951 359953 360955
      364955 369952 374947 381938
 0.25 365744 364744 362743 361743 359744 357744 355745 354746
      352748 351749 351750 350751 351753 353754 355754 356754
      358753 360752 360751 361750 363749 363748 364746 364745
      365744
 0.25 370987 369986 368986 367987 366990 367991 369990 369989
      370987
 0.50 501238 501236 501235 500234 498233 497234 497237 497239
      498239 499241 500240 501240 501238
 0.50 495246 493244 490244 487243 485244 481243 478243 476245
      475247 475251 476253 480255 483256 485255 488254 490254
      492252 494249 495246
 0.50 441870 440866 438865 435871 433876 430883 428888 426895
      427900 428900 430894 433888 435883 439877 441870
 0.50 348969 346966 347960 349955 348949 348940 348934 345932
      345939 344945 343949 341948 340945 337944 335948 333954
      328962 324973 325978 332979 343976 346973 348969

$$





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