Quantitative Precipitation Forecast
Issued by NWS

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233
FXUS04 KWBC 290701
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
300 AM EDT FRI JUL 29 2016


PRELIM DAY 1 QPF DISCUSSION
VALID JUL 29/1200 UTC THRU JUL 30/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

...OVERVIEW...

IT IS SUMMER...AS REFLECTED BY WIDESPREAD MEASURABLE PRECIPITATION
IN THE FORECAST DURING THE DAY 1 PERIOD...BUT LITTLE COVERAGE OF
HEAVY ORGANIZED PRECIPITATION. STILL...THERE WILL BE POTENTIAL FOR
HEAVY RAIN ON SMALLER SCALES...ESPECIALLY NEAR THE FRONTAL SYSTEM
IN THE CENTRAL U.S...AND WITH THE SHORTWAVE SKIRTING THE NEW
ENGLAND COAST...AND OVER FLORIDA. WPC ATTEMPTED TO MAINTAIN
CONTINUITY WHILE KEEPING UP WITH OBSERVATIONAL AND MODEL TRENDS.
QPF WAS BASED LARGELY ON A CONSENSUS APPROACH AND TRENDS. IT IS
HARD TO PICK OUT ANY MODEL THAT WAS PARTICULARLY FAVORED...BUT THE
NAM/GFS/ECMWF WERE ALL GIVEN A DECENT AMOUNT OF WEIGHT...AND THE
12Z SSEO MEAN WAS USED EARLY IN THE PERIOD.


...NEW ENGLAND...

LOWER PRESSURE AND PERHAPS MULTIPLE MESOSCALE LOW CENTERS WILL
TRACK ALONG WITH AN ADVECTING WARM/MOIST AIRMASS ALONG THE MID
ATLANTIC AND SOUTHERN NEW ENGLAND COASTS. MORE
SIGNIFICANT...WARM-SECTOR-STYLE...INSTABILITY MAY REMAIN JUST
OFFSHORE...BUT ORGANIZED ASCENT WITHIN A DEEPLY SATURATED AIRMASS
IS LIKELY TO YIELD AT LEAST MODERATE PRECIPITATION...ESPECIALLY
FROM LONG ISLAND TO CAPE COD. THE GLOBAL MODEL CONSENSUS AS
REFLECTED IN OUR IN-HOUSE ENSEMBLE...HAS BEEN TRENDING TOWARD A
SOLUTION MORE LIKE THE 12Z SSEO MEAN...WHICH WAS USED HEAVILY FOR
THE EARLY FORECAST PERIODS. A FAIRLY SHARP GRADIENT IS
ANTICIPATED...WITH AREAL AVERAGE RAINFALL OF 1-2 INCHES NEAR THE
COAST OF SOUTHERN NEW ENGLAND...TAPERING QUICKLY OFF TO 0.10-0.50
INCH AMOUNTS NORTH OF HARTFORD AND BOSTON.


...OHIO VALLEY / SOUTHERN GREAT LAKES...

A LARGE SCALE WEAKNESS / TROUGH REMAINS ANCHORED FROM THE GREAT
LAKES TO THE LOWER MISSISSIPPI VALLEY AS SHORTWAVES ROTATE THROUGH
IT. THE CENTER OF BETTER DEFINED VORTICITY HAS REMAINED IN THE
VICINITY OF THE WESTERN AND SOUTHERN GREAT LAKES OVER THE PAST
DAY...AND WILL CONTINUE TO PRODUCE A LITTLE GREATER COVERAGE OF
DIURNALLY ENHANCED CONVECTION TODAY OVER PARTS OF IL/IN/MI/OH. WPC
QPF WAS LARGELY BASED ON A BLEND THAT INCLUDED THE
NAM/GFS/ECMWF...AND ALSO THE SSEO MEAN FOR EARLIER PERIODS. THE
RESULT IS LITTLE CHANGE FROM THE PREVIOUS FORECAST EXCEPT TO PULL
QUARTER INCH AMOUNTS FARTHER WEST THROUGH ILLINOIS PER THE 00Z GEM
REGIONAL...A MODEL THAT PERFORMED WELL WITH CONVECTION THE
PREVIOUS DAY.


...PLAINS AND MID/LOWER MISSISSIPPI VALLEY...

LOW LEVEL WINDS WERE ON THE WEAK SIDE...BUT THE RECENT
ESTABLISHMENT OF AN EAST-WEST FRONTAL ZONE OVER THE PLAINS HAD
ALLOWED FOR WEAK UPSLOPE FLOW TO DEVELOP IN THE PRESENCE OF A
SEMI-ACTIVE NORTHWEST FLOW PATTERN ALOFT. THE PATTERN FAVORS
FAIRLY WIDESPREAD PRECIPITATION FROM EASTERN CO/NM ACROSS KS/OK
INTO MO/AR/TN/MS...WITH SCATTERED PRECIPITATION FARTHER NORTH AS
WAVES ACT UPON RESIDUAL ELEVATED MOISTURE BEHIND THE FRONT IN THE
CENTRAL/NORTHERN PLAINS. MODELS SHOW DECENT AGREEMENT AS TO AREAL
COVERAGE...BUT VARY A LOT IN THE DETAILS OF QPF
MAGNITUDE...ESPECIALLY AS THEY ALL TEND TO DEPICT ONLY SMALLER
SCALE MAXIMA AT THIS TIME. ONE OF THE BETTER QPF SIGNALS IS ACROSS
SOUTHERN KS / NORTHERN OK HEADING EASTWARD INTO MO/AR...WHERE IT
APPEARS THAT AN ORGANIZED MCS COULD TRACK THIS MORNING AS
CONVECTION GROWS UPSCALE OUT OF COLORADO AND WESTERN KANSAS. IF
THIS OCCURS...THE RESULTING OUTFLOW AND PERHAPS MCV ALOFT COULD
LEAD TO ORGANIZATION ALONG AN ELONGATED AXIS EXTENDING FROM
ARKANSAS INTO SOUTHERN OKLAHOMA BY AFTERNOON/EVENING. BACK NORTH
AND WEST IT IS POSSIBLE THAT ADDITIONAL CLUSTERS OF STORMS WOULD
FORM IN THE AFTERNOON...GIVEN AMPLE RECOVERY OF INSTABILITY WITHIN
AN OTHERWISE UNCHANGED SYNOPTIC PATTERN. QPF HERE WAS PIECED
TOGETHER TO TRY TO KEEP A METEOROLOGICALLY CONSISTENT PROGRESSION
THROUGH EACH 6-HOUR PERIOD...BUT CONFIDENCE IN THE DETAILS SHOULD
BE CONSIDERED MODERATE AT BEST. WE HAD SOME PREFERENCE FOR THE
WRF-ARW AND NAM BOTH PICKING UP ON THE ELONGATED AXIS INTO
SOUTHERN OK...WITH THE NAM AND SOME OTHER GUIDANCE ALSO POINTING
TOWARD AN ACTIVE AFTERNOON ALONG THE TRAILING PORTION OF OUTFLOW /
EFFECTIVE FRONTAL BOUNDARY OVER THE TX PANHANDLE.


...WEST...

ON THURSDAY CONVECTION HAD FIRED AS FAR NORTH AS THE NORTHERN
SIERRAS...WHILE THE BULK OF ACTIVITY REMAINED DOWN IN ARIZONA.
GOING FORWARD...THE MODELS ACTUALLY SHOW A GOOD DEAL OF
AGREEMENT...WITH SPOTTY MEASURABLE PRECIPITATION THROUGHOUT THE
MORE EASILY FAVORED TERRAIN OF THE SOUTHWEST STATES. WPC QPF USED
A COMBINATION OF THE NAM/GFS AND NDFD.


...FLORIDA...

FLOW BECOMES A BIT MORE SOUTHERLY TODAY AND A SLUG OF DEEPER
MOISTURE OFF THE SOUTHWEST COAST WAS POISED TO MOVE TOWARD CENTRAL
FLORIDA. THIS SHOULD PROVE FAVORABLE FOR GREATER RAINFALL
PRODUCTION RELATIVE TO RECENT DAYS...AS SEA BREEZES WILL MEET IN
THE MIDDLE OF THE PENINSULA AND FIND A SOUPIER AIRMASS WAITING
THERE. WE TOOK A MODEL CONSENSUS APPROACH AND BUMPED UP QPF
ACCORDINGLY...WITH AREAL AVERAGE AMOUNTS APPROACHING 0.75 INCHES
DOWN THE CENTER STRIPE OF THE PENINSULA.

BURKE

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

24HR QP VT 30/12Z
 0.01 543185 545173 546162 544141 543133 541126 536120 532116
      527113 520110 518108 514107 509110 505115 504119 503123
      504130 509138 516148 517151 517157 513160 501161 493160
      486161 483165 482169 483172 488175 492178 492183 496184
      500183 502186 505193 506203 504210 506218 509225 514226
      519222 522217 530205 536193 543185
 0.01 503155 504147 504143 503140 497134 492127 490124 485123
      476116 475111 477105 477099 476094 472088 468084 465080
      460072 458067 454066 447060 441059 437060 434061 432058
      435053 436048 437042 441044 445046 448043 448037 444028
      438022 444019 454015 459016 462015 470011 473009 475004
      477999 481995 485995 489992 491986 492982 492975 489969
      482962 476957 470960 462966 455971 450978 448982 445983
      437988 433986 431982 426975 415963 402949 399947 397943
      394935 392929 391921 389908 387892 390887 393884 398886
      400887 400891 399896 399902 400917 403925 408934 416938
      420938 423936 427930 432922 439916 443906 445901 443898
      443894 440890 438884 437876 437869 437855 438842 446825
      446821 443816 441805 434801 430797 428791 424782 422780
      420774 420767 423764 430758 434756 437752 440748 439742
      441735 444731 451723 454718 455713 457702 457695 460690
      465683 468679 469675 470663 470658 467653 462644 460641
      456640 451645 446647 442646 434644 428645 425648 418657
      412667 407675 402683 399686 398691 383725 380729 377732
      369738 365728 361728 358731 352733 348737 342744 331757
      320774 319778 316783 315787 315792 317796 320798 323801
      327801 333797 339789 344782 348784 348790 346800 346805
      344809 341813 340817 338823 338827 331835 327839 324838
      325837 327833 329827 324822 316826 309833 307832 306828
      308823 311815 308810 300806 283802 278801 274800 266799
      259794 255796 253799 251804 248807 247810 250814 261831
      277839 285843 291849 294851 294857 291866 287886 285897
      285903 286906 282914 283925 290929 292932 293938 284959
      279969 273969 270968 261969 257971 255974
 0.01 255974 255978 258982 260990 262993 267994 270995 271999
      272003 278003 281997 277984 288984 292985 295983 302967
      305960 305953 303948 304937 306934 308935 312937 314935
      313926 314922 316919 319920 323920 327922 328929 328935
      327941 330958 331969 331975 330980 332002 330013 330026
      325044 326077 325089 324093 321096 314099 310099 308097
      304094 301089 297082 293075 293069 296065 301061 306055
      311054 313050 314044 313040 310032 305027 300021 298018
      294017 276014 268012 265010 263007 260000 253995 250993
      247994 243995 240997 240007 245016 250022 253028 256032
      253035 249040 247044 246049 245059 242068 241070 243073
      250086 254094 260097 275105 292112 300116 305123 310130
      316134 321136 326135 328132 328126 327121 328116 331115
      336115 338119 340128 343134 346138 343141 336145 336150
      341153 344156 349157 354159 354164 357165 359162 362160
      365162 372168 373173 371177 366178 364180 361183 361184
      368190 372192 375195 380199 384201 388202 392201 397203
      400204 403203 406215 410207 409202 412199 417192 419188
      420183 417180 415181 414184 410185 407186 407180 407175
      406170 414161 419153 421150 424148 425143 421142 416142
      413142 406137 402134 397132 392132 389130 387125 389121
      395116 396113 394110 387113 383112 381111 381108 386104
      392098 396092 399082 403074 403069 405064 408066 413067
      422071 426073 428075 434076 437074 442077 444079 447082
      449086 447089 444087 437082 434080 431082 430085 428084
      424084 423088 424091 426094 430094 453107 456116 456122
      458125 464132 467140 471148 474151 476147 475141 476138
      478137 480140 485141 489142 491145 495149 498154 503155
 0.01 420235 421229 419225 417220 413219 412223 409227 406230
      403228 399227 398230 400232 404235 409236 414237 418237
      420235
 0.01 410101 409100 409098 408096 406097 405098 405100 405102
      406103 407105 408105 408103 409101 410101
 0.01 410010 408006 406003 404998 406996 408989 407986 405985
      401986 399991 398998 398005 398011 400016 404018 407016
      409012 410010
 0.01 391080 385070 385065 384062 381061 378065 379073 383076
      383081 381081 376084 371086 370080 367076 363076 362078
      364084 367090 367097 370104 373104 377103 381099 380092
      382088 387084 391080
 0.01 358114 358111 359109 358107 357105 357104 356102 354101
      352100 350100 349100 348101 348102 349103 350105 351106
      352107 352108 353110 354111 355112 355113 356114 358114
 0.01 345178 346174 346169 347167 345164 343164 340165 338163
      334162 332162 330164 330166 333169 335170 339171 342173
      343175 343178 345178
 0.01 306930 306928 305927 304928 304931 305932 306930
 0.01 269033 269031 268030 267029 266028 265029 266031 267033
      268034 269033
 0.25 535158 535150 534141 530136 527131 524126 520120 518122
      517127 517131 520137 522144 524152 526157 530159 535158
 0.25 441665 439660 435659 430659 424660 421663 418668 413677
      404694 401704 398714 395725 394731 395738 397745 399747
      404749 410747 415741 420733 423729 427729 432727 435723
      435717 432713 431707 432702 437680 440672 441665
 0.25 439007 437004 434001 432997 429993 426991 421992 420996
      420999 418002 422005 425007 429006 432006 437008 439007
 0.25 431821 429816 424816 419816 417809 417803 415801 412801
      407803 405806 401809 397808 393810 391814 389821 386825
      382827 378825 373824 369825 362831 357837 352846 348849
      345853 342862 330866 323872 320878 319880 318888 321895
      320899 324907 333916 333938 338972 340008 346024 360040
      358048 359051 361052 372053 374051 373046 368038 363027
      361023 360015 361008 360002 353995 350991 348987 347981
      349976 353983 355987 358991 367997 371000 374003 378006
      381006 385001 386995 386980 385968 386963 388959 389951
      388944 383932 381925 380918 379906 378901 375896 372893
      375889 379881 383873 384867 382863 380861 376860 371860
      370852 371846 372840 373835 374830 378830 380834 379838
      378843 381847 384848 391845 395847 399846 402845 403846
      406852 407860 408868 410880 412886 413894 414899 416904
      422911 424907 424902 422894 423890 424888 430879 430866
      428854 429840 429830 431821
 0.25 389783 389781 388780 386780 385780 383781 382782 381783
      380784 380785 378787 379789 379791 380791 382791 384790
      385789 386788 387787 388785 388783 389783
 0.25 358750 358749 356750 354751 353753 351755 353757 355756
      357755 357754 356752 358750 358750
 0.25 342098 342096 342095 341096 340098 341100 342098
 0.25 314854 313850 310852 308858 305863 302864 301867 298879
      297886 295892 291897 291904 292910 295915 300912 303907
      309897 312885 312878 308874 309869 311862 314854
 0.25 303836 303833 302833 300832 298831 297832 296832 295834
      297835 298836 299836 301837 303837 303836
 0.25 298103 297094 293086 284074 278069 278065 279060 279057
      277054 272048 267042 264041 260042 254047 252055 252063
      252074 255081 260088 265093 271097 278101 286104 294106
      298103
 0.25 299817 293813 284811 280809 278805 274804 269806 265804
      259804 255805 252808 254812 258813 266816 269818 271822
      275824 279823 287823 296820 299817
 0.25 289054 290052 289050 289049 288047 287046 287045 286043
      284043 282044 281045 280045 279047 280048 280049 281050
      283051 285053 286053 287054 289054 289054
 0.50 435671 435666 432664 423666 415679 408692 405699 403708
      401715 400725 401733 403738 405740 410739 415733 418726
      421718 425702 430687 435671
 0.50 425869 425862 424855 425848 424841 421839 418841 414844
      413849 413854 412861 414867 417870 420872 424872 425869
 0.50 382979 382970 380961 378950 377942 380940 382936 379927
      375920 371913 366909 363906 363900 365893 368882 367877
      365874 362872 359872 356874 354878 350884 345889 342897
      340899 340904 341913 338921 336930 336942 337954 338963
      340971 344972 345968 346956 349938 352930 355927 357928
      360931 360936 361947 361957 363967 362976 365983 374996
      377996 380992 382979
 0.50 358983 358980 357979 356980 357983 358983
 0.50 354022 353018 353011 354005 351000 349997 346994 343997
      344003 345008 347013 348017 350020 354022 354022
 0.50 293100 293093 290087 285082 281078 273069 269064 268058
      269054 268051 267048 264045 260047 256053 257069 256074
      257078 260084 264088 269093 279099 287101 293100
 0.50 293818 291816 288815 285814 282814 279813 278811 276807
      274807 273810 275812 277813 279817 280819 283820 286821
      287820 290818 293818
 0.50 266812 267810 266808 265808 264806 263806 261805 259805
      258806 256807 255808 254809 254810 256811 258811 259811
      260812 262812 264813 266813 266812
 1.00 431675 431670 428670 423673 415683 410695 406707 403720
      403727 406733 410733 413727 418716 422702 425690 430678
      431675
 1.00 378972 377968 376965 375963 373960 371958 368958 367961
      367965 368970 368972 370974 373975 376974 378972
 1.00 362892 362889 363887 362885 362883 361882 359883 359885
      358888 357890 357892 358894 358896 358898 360896 360894
      362892 362892
 1.00 351921 350919 350918 348917 346918 346919 344920 344921
      343923 342923 341925 341928 343929 344928 344927 346926
      347925 348924 349923 350922 351921
 1.00 284095 284091 284088 282085 279082 274077 271073 265070
      262072 262076 264082 268085 272089 276093 283095 284095
 1.50 428678 428675 425675 422679 416686 413694 409704 408708
      408714 408719 407723 409726 411725 413721 416712 420702
      422693 426684 428678
 2.00 422689 422687 422685 421684 420685 419686 418688 416690
      416691 415693 415694 414696 414699 415701 416701 416700
      418699 418698 419696 420695 420693 421692 422690 422689

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