Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 030657
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
257 AM EDT SUN MAY 03 2015


PRELIM DAY 1 QPF DISCUSSION
VALID MAY 03/1200 UTC THRU MAY 04/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

...MIDWEST AND CENTRAL PLAINS...

A SMALL BUT ORGANIZED MCS WAS PASSING THROUGH OMAHA AROUND 06Z
THIS MORNING. THIS WAS WELL BEHIND A MID LEVEL TROUGH THAT WAS
ANALYZED FROM CENTRAL IA TO EASTERN KS AT 00Z...BUT CONVECTION HAD
BEEN FORCED BY STRONG HEATING WITHIN THE BROADER INSTABILITY AXIS
ACROSS CENTRAL NE SATURDAY EVENING. A SMALL MESOSCALE CONVECTIVE
VORTEX WAS EVIDENT IN RADAR IMAGERY...WHICH MAY SUPPORT ADDITIONAL
0.10 TO 0.25 INCH AREAL AVERAGE RAIN THE NEXT FEW HOURS DOWNSTREAM
INTO SOUTHWEST IA. THE SYSTEM SHOULD GRADUALLY DISSIPATE AS IT
MOVES OFF THE INSTABILITY AXIS...AND WE USED A COMBINATION OF THE
HRRR AND WRF-ARW WITH OBSERVATIONAL TRENDS FOR THE NEAR TERM QPF.
FARTHER EAST...SLIGHT LIFT HEIGHT FALLS AND WARM ADVECTION WERE
ACCOMPANYING THE AFOREMENTIONED TROUGH...WHICH WILL SUPPORT LIGHT
PRECIPITATION THROUGH MORNING IN EASTERN IA INTO IL. PER
FORECASTING SOUNDINGS AND PLAN VIEW CAPE FORECASTS...BOTH THE MCV
IN WESTERN IA AND MID LEVEL TROUGH IN EASTERN IA SHOULD PROVE TO
BE LESS PRODUCTIVE DURING THE NEXT DIURNAL CYCLE...BY WHICH TIME
THEY WILL BE IN EASTERN IL HEADING EAST. WIDELY SCATTERED SHOWERS
CANNOT BE RULED OUT...BUT FROM AN AREAL AVERAGE PRECIPITATION
SENSE...WE ALLOW THE EVENT TO DISSIPATE WITH TIME.

ATTENTION THEN TURNS TO A WELL DEFINED FRONT IN THE NORTHERN
PLAINS WHICH MODELS AGREE WILL EXTEND FROM THE U.P. OF MICHIGAN
AND NORTHERN WI DOWN TO CENTRAL NE AT 21Z TODAY. WEAK HEIGHT FALLS
AND WEAKLY DIFLUENT MID LEVEL FLOW WILL SUPPORT SCATTERED
SHOWERS/STORMS PRIOR TO THAT TIME ACROSS MN/WI...BUT EXPECT A
MARKED INCREASE IN CONVECTIVE ACTIVITY TOWARD PEAK HEATING SUNDAY.
MODERATE INSTABILITY IS FORECAST TO DEVELOP ALONG THE LENGTH OF
THE FRONT AT LEAST AS FAR NORTH AS NORTHERN WI. SOME OF THE MODELS
INDICATE TWO AREAS OF HEAVIER PRECIPITATION...LOCATED FROM
NORTHERN/CENTRAL WI EASTWARD WITHIN A REGIONAL MAXIMUM WARM
ADVECTION / MOISTURE TRANSPORT...AND ALSO INITIATING IN NORTHERN
IA WHERE ONE OF THE BETTER BALANCES BETWEEN FORCING AND
INSTABILITY WILL BE STRUCK. FARTHER SOUTH...STRONG HEATING AND
ARRIVAL OF THE SURFACE FRONT SHOULD AGAIN YIELD ORGANIZED ACTIVITY
OVER EASTERN NE AND MOVING INTO ADJACENT PARTS OF IA/KS/MO.

THE PREVIOUS FORECAST HAD A REASONABLE HANDLE ON ALL THIS. WE
BLENDED TOWARD THE 00Z NAM AND 12Z WRF-NMM AND NSSL WRF WHICH KEPT
GOOD CONTINUITY WHILE BETTER EMPHASIZING THE LOCAL
MAXIMA...ESPECIALLY IN THE MORE STRONGLY FORCED REGIME OVER
WI...WHERE AREAL AVERAGE AMOUNTS ARE FORECAST TO EXCEED 1 INCH.


...SOUTHWEST / GREAT BASIN /CENTRAL TO SOUTHERN ROCKIES...

BROADLY DIFFLUENT FLOW IS EXPECTED ACROSS THE SOUTHWEST QUARTER OF
THE U.S. DOWNSTREAM OF THE WEAK BUT STRENGTHENING UPPER LOW OFF
THE CALIFORNIA COAST. WIDELY SCATTERED DIURNAL CONVECTION IS
LIKELY ACROSS THESE AREAS. ONE OF THE BETTER ORGANIZED EVENTS IS
EXPECTED IN NORTHEAST CO AND SOUTHEAST WY...WHERE BROAD
CONVERGENCE...LIFT...AND CLOUD BASE INFLOW WILL BE ENHANCED BY THE
ARRIVAL OF A FRONT. OVER MUCH OF THIS REGION THE UPDATED WPC QPF
REPRESENTS A BLEND OF THE PREVIOUS FORECAST WITH THE 00Z NAM AND
21Z SREF MEAN. THE GFS AGAIN APPEARED OVERDONE IN COVERAGE. WE DID
INTRODUCE A FEW NEW AREAS OF PRECIPITATION... THOUGH...NAMELY IN
SOUTHERN ARIZONA...WITH INCREASED SOUTHERLY INFLOW AND MID LEVEL
ASCENT LIKELY TO INTERACT WITH OUTFLOWS COMING OFF THE MOGOLLON
RIM - AND OVER SOUTHWEST TEXAS...WHERE DIFLUENT FLOW...STRONG
HEATING...AND A BREAKABLE CAP SUGGEST AN ACTIVE AFTERNOON/EVENING
FROM THE DAVIS MOUNTAINS TO THE SIERRA MADRES. IN TEXAS THE 00Z
NSSL WRF AND NAM CONEST SERVED AS A GUIDE FOR OUR QPF.

BURKE

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

24HR QP VT 04/12Z
 0.01 495888 495875 494870 491868 487865 488859 489847 483816
      486805 487800 486797 483788 480786 478787 476785 469786
      466787 463789 453796 444812 439820 436829 429846 425850
      420857 416863 412868 403880 399887 395895 392913 389934
      386945 381953 375968 374974 373976 372988 368997 362000
      350010 337009 332012 329016 328018 325022 324025 323029
      324033 328034 333032 337032 341030 353024 356021 361020
      369020 378018 383022 385024 386027 386030 385034 382038
      380040 378042 376040 371036 367036 365039 362043 356048
      352050 349048 338047 331052 331058 335058 338056 342051
      347050 351053 355060 354065 352067 348068 345070 342069
      338071 335073 334077 336081 337086 335092 332093 330095
      325095 323098 323102 324111 324118 325122 326122 330125
      331129 334132 337132 342129 346128 350128 353127 356131
      359132 364133 367135 370136 379133 384127 393120 399125
      394130 392140 391144 394146 397150 395156 391159 389163
      387166 385171 387173 391175 394177 396175 398173 400169
      405163 411160 413157 414161 416166 419169 423166 424162
      425158 426147 426136 426126 428122 431119 433116 440115
      442119 443124 437141 438149 445148 452149 453144 452140
      451129 449124 450117 455099 456094 454090 447090 444088
      440086 439082 439079 442078 444079 448082 451085 455086
      456083 455079 453071 453064 454061 455055 457051 457041
      455034 452029 449027 444023 431017 426009 424005 424999
      424993 426988 431981 437973 441965 444959 449953 450959
      453960 459956 468945 477930 481922 485915 490901 495888
 0.01 456720 453715 447712 444710 438709 432711 426712 424718
      424722 426724 427727 430726 434725 437727 442725 449724
      452724 454722 456720
 0.01 392197 392194 392190 390185 387182 383180 378179 374181
      371183 372188 374192 379194 382196 388198 392197
 0.01 403102 404091 402084 396087 395086 391087 387091 382090
      374078 371072 366074 363076 363078 368083 377091 378095
      378100 374105 370110 370114 373113 377113 380112 386109
      397103 403102
 0.01 314037 315032 314029 311024 307013 305006 303000 301994
      297990 293991 291993 288997 280005 276012 272017 273021
      274025 278025 285026 290028 295031 299034 306035 311037
      314037
 0.01 304806 303797 297794 289792 282791 273792 265794 264798
      266800 270804 278805 285807 291810 294811 299811 304806
      304806
 0.01 307968 305964 304960 301957 297955 294956 292960 288964
      286968 288970 292971 297973 301973 305971 307968
 0.01 303918 303916 303914 303913 301912 301910 301909 299907
      297907 295907 295908 295910 297912 299914 300916 300918
      301919 303918 303918
 0.01 292901 293897 291893 290891 288889 285887 283889 284894
      285896 285900 287902 289904 290904 292901
 0.01 250818 249808 245803 241801 239805 238809 236811 235816
      235824 236834 237837 240839 243840 246838 246834 248831
      249822 250818
 0.25 476865 476857 475849 473839 467834 463832 459832 454834
      450837 445843 436857 432867 431871 431878 428886 424890
      420889 416889 413890 410901 409905 409911 409924 408936
      406947 403956 400966 396975 396979 398983 404978 407977
      409980 410984 410989 414984 416980 415976 416972 418968
      425962 430957 435950 439942 445935 450928 455922 459915
      467897 469888 472878 476865
 0.25 414031 413027 411025 404023 401020 397020 395024 395029
      393039 390047 388049 390052 391055 395056 400057 407058
      407047 408041 410038 414032 414031
 0.50 468871 468862 466856 462854 459852 460846 456844 449849
      442855 438863 436870 437877 440880 438885 433907 427909
      424913 421924 421930 421937 422942 426944 431942 434938
      440930 444928 447925 452918 455913 457907 460898 464886
      467876 468871
 0.50 401037 401035 401032 400030 399030 398029 398030 398031
      399032 398033 398034 398037 399039 400039 401037 401037
 1.00 456889 455884 455879 454874 452873 451875 449878 447881
      446884 445887 444890 444894 446896 450896 452894 454891
      456889

$$




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