Quantitative Precipitation Forecast
Issued by NWS

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959
FXUS04 KWBC 041834
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
233 PM EDT WED MAY 04 2016


PRELIM DAY 1 QPF DISCUSSION
VALID MAY 05/0000 UTC THRU MAY 06/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

...FLORIDA...

CONVECTION WITH HEAVY RAIN APPEARED TO HAVE BEEN BETTER FOCUSED
DURING THE MORNING HOURS...BUT HAD BECOME MORE OUTFLOW DOMINANT BY
MIDDAY. THIS WAS IN PART DUE TO BOUNDARY LAYER HEATING/DRYING AND
STRENGTHENING MID LEVEL WESTERLIES WITHOUT A CORRESPONDING
ACCELERATION OF LOW LEVEL INFLOW. IT WAS ALSO...IN PART...DUE TO
INITIATION OF A RING OF CONVECTION OVER SOUTHEAST FLORIDA...AHEAD
OF THE MORE STRONGLY FORCED LINE UP TO THE NORTH. THIS WILL HAVE A
STABILIZING INFLUENCE...AND THE OPPORTUNITY FOR INTENSE RAINFALL
ACCUMULATIONS WAS DECREASING...ALTHOUGH VERY MOIST SOUTHWESTERLY
LOWER LEVEL FLOW IMPINGING UPON OUTFLOW BOUNDARIES MAY STILL YIELD
SPOTTY TWO INCH PER HOUR RATES AS DETAILED IN RECENT MESOSCALE
PRECIPITATION DISCUSSIONS.

FARTHER NORTH...A SECONDARY MAXIMUM OF PRECIPITATION WAS OCCURRING
NEAR THE SURFACE COLD FRONT TOWARD GAINESVILLE AND SAINT
AUGUSTINE. THIS ACTIVITY IS FORECAST TO REDEVELOP SOUTHWARD BEFORE
SHOVING OFFSHORE WITH THE MID LEVEL WAVE THAT WAS WAS FORCING THE
ACTIVITY. FOR QPF...WPC RELIED ON TRENDS IN THE HRRR AND ESRL
EXPERIMENTAL HRRR...ALONG WITH THE NSSL WRF. GIVEN THE OUTFLOW
DOMINANCE IN SOUTHERN FLORIDA...THOUGH...OUR QPF MAY BE A LITTLE
TOO SLOW TO MOVE OUT THIS EVENING.


...GREAT LAKES / OHIO VALLEY / MID ATLANTIC...

THE 546 DECAMETER CLOSED LOW DROPPING TOWARD THE SOUTHERN
APPALACHIANS REPRESENTS LARGE ANOMALIES...4 STANDARD DEVIATIONS
BELOW THE CLIMATOLOGICAL MEAN...BY THE TIME IT DIGS INTO THE
SOUTHEAST STATES. PERSISTENT DIFLUENT FLOW NEAR AND JUST
EAST/NORTHEAST OF THE CLOSED LOW WILL SUPPORT RELATIVELY FOCUSED
AND PERSISTENT RAINFALL FROM THE CENTRAL TO SOUTHERN APPALACHIANS
AND IN THE PIEDMONT OF VA/NC. WITH THE LARGER SCALE WARM CONVEYOR
BELT WELL OFF THE EAST COAST...HOWEVER...THIS SYSTEM WILL WORK
WITH VERY MODEST MOISTURE AND WEAK INSTABILITY...SUCH THAT HEAVY
OR EXTREME RAINFALL IS UNLIKELY. THIS THINKING MAKES THE GFS STAND
OUT AS AN OUTLIER WITH ITS 24-HOUR 4-PLUS INCH MAXIMUM OVER WV/VA.
SOME OF THE HI-RES MODELS PRODUCE 3 INCH AMOUNTS...BUT IT WOULD
SEEM THAT SUCH AMOUNTS WOULD AFFECT A SMALL AREA...AND WITHOUT ANY
SUSTAINED LOW LEVEL INFLOW IT IS HARD TO HAVE TOO MUCH CONFIDENCE
IN HEAVY AMOUNTS OCCURRING HERE. THE WPC FORECAST WAS PRETTY CLOSE
TO THE MORE CONSERVATIVE NAM AND UKMET...SO WE MADE VERY LITTLE
CHANGE TO THE QPF OVER THIS REGION.


...NEW ENGLAND...

A WAVY FRONT WAS POSITIONED OFF THE MID ATLANTIC AND NEW ENGLAND
COASTS AND DOWNSTREAM FROM THE DEEP AND SLOW MOVING LONGWAVE UPPER
TROUGH AFFECTING THE EASTERN STATES. TWO ROUNDS OF LIGHT
PRECIPITATION ARE EXPECTED FROM THE COASTAL MID ATLANTIC INTO NEW
ENGLAND TODAY AND TOMORROW AS A WEAK FRONTAL WAVE AND THEN A
STRONGER FRONTAL WAVE OCCURS. THERE IS QUITE A RANGE IN THE QPF
GUIDANCE...WITH SOME MUCH DRIER SOLUTIONS LIKE THE GFS AND GEM
REGIONAL...AND SOME MUCH WETTER SOLUTIONS LIKE THE PRIOR RUN OF
THE ECMWF. THE 12Z GUIDANCE SEEMS TO HAVE CONVERGED TOWARD THE
MIDDLE...AND TOWARD THE PREVIOUS WPC FORECAST SO THAT AGAIN...LIKE
IN THE OHIO VALLEY...WE MADE RELATIVELY FEW CHANGES DURING THIS
CYCLE. THE AREA AROUND CAPE COD COULD SEE OVER AN INCH OF RAIN IN
THE 30 HOUR PERIOD ENDING THURSDAY AFTERNOON. AREAL AVERAGE
QUARTER INCH ACCUMULATIONS ARE FORECAST WEST TO NEAR MANHATTAN TO
SOUTHERN NH/ME.


...WESTERN U.S...

THE FORMERLY FULL LATITUDE EASTERN PACIFIC UPPER TROF CONTINUES TO
SPLIT INTO TWO PIECES DAY 1. THE PRIMARY CENTER WILL BE THE
SOUTHERN PORTION CLOSING OFF ALONG THE NORTHERN TO CENTRAL
CALIFORNIA COAST---WHILE THE NORTHERN PORTION REMAINS MORE
PROGRESSIVE INTO B.C. CANADA. AN AXIS OF ABOVE AVERAGE PW VALUES
TO THE NORTHEAST OF THE CLOSING UPPER LOW WILL REMAIN ACROSS
NORTHERN CALIFORNIA INTO THE PACIFIC NORTHWEST.  BROADLY DIFLUENT
UPPER FLOW IN THIS HIGH PW AXIS WILL SUPPORT A WIDESPREAD REGION
OF LIGHT TO MODERATE PRECIP TOTALS...WITH ISOLATED HEAVY TOTALS
POSSIBLE. WPC LEANED TOWARD OUR IN-HOUSE ENSEMBLE AND SREF...WHILE
MAINTAINING A GOOD PERCENTAGE OF CONTINUITY...AND ATTEMPTING TO
PRESERVE SOME DETAIL IN THE MOUNTAINOUS TERRAIN.

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

BURKE

24HR QP VT 06/00Z
 0.01 464622 468626 470630 474640 475647 474652 475659 475665
      474677 472689 469701 465712 461721 459725 456728 451731
      448732 439732 424744 420748 419751 420754 425755 430757
      432759 433766 430776 424794 420804 419808 420811 422818
      425823 428826 435830 438833 443833 447831 451833 457837
      459839 459845 457851 455855 450857 446858 428867 410873
      405873 401872 397874 394874 380862 376860 376857 373855
      363852 361849 356850 349855 343860 340863 339867 335859
      334852 335846 341838 347831 352824 354819 354814 354811
      352809 347810 342805 343800 342793 341779 342768 343761
      345756 350754 355754 366752 376750 379748 385746 392741
      396737 398731 398728 395727 390726 386729 381731 376730
      373727 366734 360739 356739 353735 353728 354723 357713
      360702 364692 367684 372676 379671 383668 387666 403655
      421642 427639 434636 441632 447628
 0.01 535190 536182 535177 533165 531161 531157 533150 534145
      535136 532133 526126 521133 518136 514139 510140 506139
      502137 499133 488119 485117 480117 479123 475125 472117
      469115 465119 437146 435157 436163 433166 425162 421161
      418165 415169 411171 408168 408164 406163 404169 402171
      399173 397170 394165 385163 378162 384168 387172 388176
      391179 396181 393184 389186 383185 378186 379183 375182
      365180 359180 356181 351182 348184 345186 342186 335174
      332178 334182 339190 343192 344197 344201 346207 361217
      384228 389236 395242 396245 401247 410249 418249 428250
      439249 443248 447246 452238 450232 448232 446231 447229
      450227 457226 474221 483220 488219 493221 496224 500227
      505235 511239 514235 514227 513223 510219 508212 510205
      512202 516200 526201 528198 532198 535190
 0.01 504931 503927 504923 504916 500915 493917 489918 486921
      480926 478925 477922 477917 479907 478896 476894 473895
      467902 462907 460910 460918 465922 467925 468932 469937
      470942 474950 476959 482955 488952 494945 499940 504932
      504931
 0.01 490134 489132 488131 486131 485133 486134 487135 489135
      490134
 0.01 480109 475103 470103 468100 463099 461102 458103 456102
      453095 450094 448092 448098 447101 445101 443099 442093
      440088 436090 433092 430089 428090 428095 429098 427102
      423103 420105 417109 414113 411113 413103 408098 404107
      401111 398113 392113 388115 383114 380113 378114 379119
      378122 376123 375125 384127 385121 388117 391117 393119
      395122 398124 403125 406125 407129 411133 412132 414127
      417123 420123 419127 417135 419132 419129 421126 423124
      420119 424115 426115 424112 427110 430109 445111 451117
      457118 459116 457112 459109 461109 464112 467108 473109
      477111 480109
 0.01 466162 465160 463160 462161 463163 464163 466162
 0.01 464747 463741 459739 451740 448742 443744 436751 436755
      439758 440764 440772 440776 441779 443781 446781 449778
      455772 459763 462753 464747
 0.01 445177 445174 444173 442172 441171 439171 437172 437175
      435177 436179 436180 435182 436184 437184 439182 440182
      441180 442180 443179 443178 445177
 0.01 393219 392217 390217 388216 387216 385216 386219 388219
      390219 392219 393219
 0.01 401072 396064 397059 397057 392057 389061 385063 382064
      379062 371062 375065 378071 380074 386077 388082 391082
      394078 390075 388069 389066 393066 395067 398069 401072
      401072
 0.01 387093 385090 384090 383092 385093 387093 387093
 0.01 367196 366194 365192 363191 362190 360190 360191 358192
      357194 356196 357198 358199 360199 360198 362197 362196
      364197 366197 367196
 0.01 371107 371106 370106 368104 367101 366101 365101 363101
      362103 363103 364105 364106 366106 368106 369108 369109
      370109 371107 371107
 0.01 364157 363155 363154 363155 362157 364157 364157
 0.01 360092 358091 357091 355093 353093 355093 356094 358094
      360092 360092
 0.01 348172 349170 349168 349165 347164 346165 345166 344167
      344169 346170 348172 348172
 0.01 354084 352083 348083 346083 343084 342080 341080 337082
      336083 333084 333087 337086 340089 342090 346090 346088
      350086 352086 354084
 0.01 317791 317787 315784 311780 306776 301772 296770 290769
      280770 273772 267769 262767 259766 254766 246767 242771
      238776 235782 233788 229800 228817 229825 231831 232841
      234848 238852 242852 244850 252840 255835 259830 264825
      267821 288817 299811 309802 314796 317791
 0.25 529178 529173 527169 523160 516154 512152 509152 501154
      494158 491160 489164 486177 488186 486196 484199 480201
      472203 470208 470214 475215 479214 492207 498201 504196
      511192 518189 520185 523183 528181 529178
 0.25 462671 460661 458654 456650 454647 448646 442648 436649
      432649 428650 421653 400668 389674 383677 377682 372693
      367705 367710 371713 376720 381721 393716 401715 405719
      409726 413730 415731 420730 425727 434718 443708 456687
      460679 462671
 0.25 458175 458174 458172 457170 457169 455168 454169 453169
      452171 451173 451176 452177 454178 456177 458175 458175
 0.25 456162 457160 457157 456157 455159 456162 456162
 0.25 447219 446216 442214 440211 442208 442203 444201 445198
      443196 442190 440191 436198 431203 425205 426214 427224
      431226 434225 440220 444221 447220 447219
 0.25 450185 450183 450182 448181 447182 446183 446184 444186
      444187 443188 444190 445190 447192 448192 448190 449187
      449186 450185
 0.25 420238 420231 419228 420222 418220 415216 412218 410217
      410214 414212 420207 420204 420201 416197 411196 408198
      403199 400197 398194 396194 393193 384193 381197 380199
      383204 386207 394211 399218 407223 407227 403228 393227
      391230 395234 402239 406241 410241 412240 416240 420238
 0.25 415793 405771 401772 398774 395774 382774 379769 375766
      368765 364762 358761 351763 349766 348769 349778 363798
      362802 365807 367810 368812 364816 358825 352837 353840
      357840 360836 363831 365829 368829 379832 385832 390829
      397828 402826 406821 408815 415793
 0.25 376216 376214 375213 374214 374216 375216 376216 376216
 0.25 381777 381775 380774 380775 381777 381777
 0.25 367210 366208 366207 365206 364207 364208 365209 366210
      367210
 0.25 297788 295783 290781 284781 279782 274783 269781 264779
      260774 256773 250773 245776 243781 238789 236794 234800
      233812 233818 235824 237836 239839 242838 245833 249824
      252820 257817 260807 263802 268798 272797 271802 273808
      277812 282811 286807 292798 297788
 0.50 524174 523170 521167 517164 513165 509164 506166 504174
      498180 496182 494187 496190 500191 504185 509183 513182
      515179 519172 524174
 0.50 458670 452662 451654 446653 438658 427664 417667 405672
      401675 395676 385682 379690 375701 378714 380716 383716
      387712 396708 401706 406708 411717 414720 419721 423720
      427716 435708 440700 443696 447692 453684 456679 458672
      458670
 0.50 415234 415231 413229 411228 409230 407232 404232 401231
      397231 400234 402235 405237 408237 411236 413236 415234
 0.50 409218 407214 404210 402208 403204 400201 397197 393198
      388197 386199 387202 390205 394207 397210 400213 403218
      408219 409218
 0.50 409794 407790 405789 397785 383781 377778 373776 369772
      365768 361765 358764 353765 351769 354779 359786 364791
      371795 376803 380809 382814 379818 377821 379822 384824
      388824 395819 400811 404806 408798 409794
 0.50 288795 289791 287788 284789 282792 280793 279795 277797
      275799 274801 274804 276807 278808 280807 283804 285802
      286800 287797 288795
 0.50 267792 267788 265786 259783 259778 257776 253776 247779
      245785 242791 238795 235802 235810 234816 238822 239830
      240833 242831 246821 255812 257805 261801 266796 267792
 1.00 427681 425675 421675 418676 413679 410682 407685 404688
      401692 402695 404694 410693 415691 418689 421686 426684
      427681
 1.00 400688 400687 398688 398689 400688 400688
 1.00 395796 391790 387787 381785 378782 372779 369780 369782
      371788 375793 379796 384800 388801 393798 395796
 1.00 357768 356767 354768 355769 356769 357768
 1.00 264792 260789 254788 253786 250785 248790 247796 245803
      245809 245813 248814 251813 253810 254805 257800 261797
      264792
 1.50 388792 387790 384789 382788 379787 377785 375783 372782
      372786 373788 375790 377792 380793 382794 386794 388792
 1.50 255795 256793 254792 253792 252794 252796 253797 255796
      255795
 2.00 379789 378789 379789

$$





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