QUANTITATIVE PRECIPITATION FORECAST DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 559 PM EDT WED MAY 04 2011 FINAL DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION VALID MAY 05/0000 UTC THRU MAY 08/0000 UTC REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR DAY 1... 18Z CYCLE UPDATE... ONLY MINOR ADJUSTMENTS WERE MADE TO ACCOUNT FOR RADAR/SATELLITE TRENDS IN THE SHORT TERM AND TO BLEND WITH THE QPF FROM THE ECMWF/18Z NAM/18Z GFS/15Z SREF MEAN OVERNIGHT AND THU. ...NERN STATES... XCP FOR SOME VRY MINOR TIMING DIFFS..THE LATEST MDL RUNS ARE IN VRY GOOD AGREEMENT CONCERNING THEIR HANDLING OF THE SYS IMPACTING THE NERN STATES THIS PD..WITH ALL LIFTING THE CLOSING OFF H5 CNTR NEWD IN NEG TILT FASHION INTO NEW ENG BY LTR THU..ACCOMPANIED BY A SFC LOW MOVG VRY SLOLY THRU ME. THE STGR ATLC INFLO AND DEEPER MSTR WL BE SWEEPING THRU ERN ME ON WED NGT AND INTO THE CANADIAN MARITIMES ON THU..SO THERE WL BE DECREASING MSTR AVBLTY WITH TIME. HOWEVER..LRG SCALE LIFT FM HGT FALLS..ENHANCED SFC CNVGNC AND FAVORABLE UPR JET DYNAMICS WL STILL SUPPORT AN ORGANIZED BAND OF RNFL..ALBEIT WITH LESSER AMTS THAN PAST DAY OR SO. THE NAM LOOKS A LTL SLO AND TOO GENEROUS WITH ITS QPF LAST 6 HRS OF THE PD OVR ME..SO LEANED TWDS CONSERVATIVE QPF SOLNS AS PER MUCH OF THE RMNDR OF THE GLOBAL GUIDANCE..WITH SOME 0.50-1.00 INCH RNFL TOTALS LIKELY FM NRN THRU ERN ME..AND WITH EVEN LESSER AMTS BACK INTO NRN NH..VT AND NY STATE. ...UPR/MID MS VLY... THE UPSTREAM H5 TROF IS ALSO HANDLED VRY SIMILARLY BY THE 12Z MDL RUNS..WITH ALL GENLY MOVG IT EWD FM THE ROCKIES INTO THE UPR/MID MS VLY. SOME STRENGTHENING OF THE SSWLY LLJ IS FCST TO OCCUR AHD OF THE H5 TROF AND SFC CDFNT..BUT THE REALLY DEEP MSTR WL RMN DOWN IN THE WRN GULF..WITH PWS PROGGED TO INCREASE/POOL TO ONLY 0.75-1.00 INCH VCNTY OF THE FNTL BNDRY. MARGINAL MSTR AVBLTY SHLD KEEP RNFL AMTS IN THE LGT-MDT RANGE..BUT RAINS SHLD BE WIDESPREAD DUE IMPRESSIVE LRG SCALE LIFT FM HGT FALLS..WAA AHD OF THE CDFNT AND SOME INCREASE IN DIFL FLO ALOFT. LEANED TWDS A BIT MORE CONSERVATIVE GFS QPF..WITH SOME GTR THAN 0.50 INCH AMTS XPCD PTNS OF MN INTO WI. DAY 2... ...NRN NEW ENGLAND... A DEEP LYR TROF AND ASSOCD CLSD LOW LIFTING NWD THROUGH NEW ENGLAND WILL BEGIN TO FINALLY EXIT THE REGION AND ADVANCE INTO THE ST LAWRENCE RIVER VLY AND QUEBEC. THE STRONGEST FORCING AND MSTR TRANSPORT WILL HAVE SHIFTED NEWD INTO THE CANADIAN MARITIMES...BUT THE MID LVL DEFORMATION ZONE SHOULD BE SUFFICIENTLY CLOSE TO THE NRN APPALACHIANS AND MAINE FOR SOME ADDITIONAL LGT PCPN. HPC QPF FAVORED A MDL CONSENSUS WITH THIS SOLN. ...GRT LAKES/OH VLY... ADDITIONAL SHRTWV ENERGY IS EXPECTED TO DIG ACRS THE REGION IN THE WAKE OF THE DEEP CLSD LOW MOVING THROUGH THE NORTHEAST. A WEAK SFC LOW AND ASSOCD FRONTAL SYS WILL ALLOW FOR A BKN AXIS OF SHWRS...PRIMARILY ENHANCED BY RATHER STEEP MID LVL LAPSE RATES. MSTR TRANSPORT AHEAD OF THE SYS SHOULD BE RATHER MODEST AND SO PCPN AMTS SHOULD BE LGT. A CONSENSUS SOLN LEANING A LITTLE MORE CLOSELY TO THE 00Z ECMWF WAS FAVORED. ...SRN FL... A WEAKENING FRONT WILL STALL OUT OVER FAR S FL OR THE KEYS AND SHOULD ATTEMPT TO RETURN NWD AS A WARM FRONT RETURN BY EARLY FRI. THE SRN END OF THE SHRTWV TROF DIGGING INTO THE GRT LAKES AND OH VLY IS EXPECTED TO INTERACT WITH THIS BNDRY AND A MORE SUBSTANTIAL POOL OF DEEPER MSTR FOR AT LEAST SOME SCT SHWRS/TSTMS. AREAL AVGS SHOULD TEND TO BE LGT TO MDT...BUT RAINFALL RATES WILL LIKELY BE HVY WITH INDIVIDUAL CELLS. ...PAC NW INTO THE NRN PLAINS... A FAST MOVING PAC SHRTWV WILL BRING SOME OROGRAPHICALLY FOCUSED SHWRS TO THE PAC NW AND INTO THE NRN ROCKIES THU NIGHT AND EARLY FRI. THE ENERGY THOUGH SHOULD PROGRESSIVELY MAKE IT INTO THE DAKOTAS BY LATE FRI. HPC QPF LEANED CLOSER TO THE 12Z GFS WITH THIS FEATURE. DAY 3... ...NRN NEW ENGLAND... DEEP LYR CYC FLOW PERSISTING ACRS ESP NRN MAINE COUPLED WITH OROGRAPHICS SHOULD ALLOW FOR SOME ADDITIONAL SHWRS TO IMPACT THE REGION. EXPECTING MUCH OF THE FOCUS TO BE ON THE HIGH COUNTRY OF NWRN MAINE IN PARTICULAR. A CONSENSUS SOLN WAS FAVORED AGAIN HERE FOR QPF. ...UPR MIDWEST SEWD INTO THE MID MS/LWR OH VLYS... UPSTREAM PAC SHRTWV ENERGY RAPIDLY ADVANCING EWD ACRS THE N CNTRL PLAINS WILL ADVANCE INTO THE MIDWEST THIS PD ALONG WITH A COLD FRONT AND WEAK AREA OF LOW PRESSURE. EXPECTING SUFFICIENT SRLY RETURN FLOW FOR MOISTURE TO BEGIN POOLING AHEAD OF THE COLD FRONT AND ESP INVOF OF WARM FRONT OVER THE MID MS/LWR OH VLYS. SWLY H85 FLOW OF 40 KTS INTERACTING WITH THIS BNDRY AND PWATS OF 1 TO 1.25 INCHES COUPLED WITH THE SHRTWV ENERGY SHOULD HELP GENERATE A BKN AXIS OF CONVECTION...IMPACTING ESP ERN MO...CNTRL/SRN IL AND INTO SRN IN/WRN KY. THESE PWATS DO NOT FAVOR PARTICULARLY HVY RAINFALL RATES...AND WITH AN EXPECTED PROGRESSIVE NATURE TO THE CONVECTION...PCPN AMTS SHOULD NOT BE THAT HVY. EXPECTING AMTS OF GENERALLY AROUND A 0.5 WITH ISOLATED HEAVIER AMTS POSSIBLE. FARTHER NORTH TWD THE UPR MIDWEST...EXPECT LIGHTER SHWR ACTIVITY GIVEN WEAKER WARM ADVECTION AND MSTR TRANSPORT. HPC QPF FAVORED A BLEND OF THE 12Z GFS AND 00Z ECMWF. ...SERN TX... THE MDLS SUPPORT AN INCREASE IN SRLY LOW LVL FLOW WHICH WILL ALLOW FOR A MORE SUBSTANTIAL INCREASE IN MSTR TO OCCUR OFF THE WRN GULF OF MEXICO. THIS COUPLED WITH WEAK SRN STREAM MID LVL VORT ENERGY WILL LIKELY PROMOTE SOME DIURNALLY DRIVEN SHWRS/TSTMS OVER THE SE TX COASTAL PLAIN AND DOWN TWD THE LWR RIO GRANDE VLY. ...NORTHWEST... STRONGER HEIGHT FALLS DEVELOPING OVER BRITISH COLUMBIA AND JUST OFFSHORE WILL BE SLIDING SEWD TWD THE PAC NW THROUGH THE PD. RESULTING BROAD DEEP LYR ONSHORE FLOW AND STEEPENING LAPSE RATES WILL BE ALLOWING FOR MORE NUMEROUS OROGRAPHICALLY ENHANCED SHWRS. THE HEAVIEST AMTS SHOULD BE OVER THE WA CASCADES AND OLYMPIC PENINSULA AND ALSO SPREADING WELL INLAND INTO THE SAWTOOTH...BITTERROOTS AND TETONS OF THE NRN ROCKIES. HPC QPF LEANED MORE CLOSELY TWD THE 12Z GFS. TERRY/ORRISON/PETERSEN GRAPHICS AVAILABLE ON THE WEB AT WWW.HPC.NCEP.NOAA.GOV 24HR QP VT 06/00Z 0.01 502633 499625 496623 492619 488619 478622 475623 471622 464618 455616 441615 431616 422619 406629 404631 403636 402642 404647 404653 402655 394659 385664 374670 370674 365676 360681 359684 352692 349696 347701 330714 316728 312735 309737 305742 295755 285769 279770 273778 267784 262791 258797 256803 255808 256813 257822 258828 262829 267827 271823 276816 279810 288795 294787 299782 305775 313769 326757 334750 344744 360734 380724 387722 393721 397722 411725 414725 417726 419730 418735 418743 421755 422763 421768 421772 422779 424783 429780 434773 438766 444763 453760 463755 472750 483747 486745 489742 498732 502723 506711 508698 508686 508680 506670 504655 503642 502633 0.01 524261 521255 519249 521232 524226 529224 532222 535217 537211 539202 538193 537188 536181 534175 528168 520158 518157 514152 507146 498140 483129 480128 474128 472130 470136 468141 465144 462150 460155 461165 463170 469171 472169 478170 481173 484177 496194 499196 503201 504205 503210 500209 498206 488208 482204 474208 471212 471221 468231 461237 458240 457244 456251 455254 457257 460259 457262 453265 451268 451273 451276 453278 458280 466281 470284 472290 474295 477298 481302 486305 495305 503304 507302 0.01 511946 510942 508939 504935 504931 506923 507915 507904 506892 503883 494876 484872 472868 463865 450866 436871 421875 409879 401882 394887 384893 367908 360920 358924 356932 355937 356942 358945 361951 365954 373961 376963 379962 387960 390958 393958 395962 393975 392984 390992 387003 385012 385018 384027 384035 385040 387042 389044 393043 397041 399038 400033 400024 402017 404004 406997 409992 414988 418986 428981 435980 441982 453982 465979 471976 477972 487966 502956 509952 511946 0.01 390800 389799 386799 384802 381804 380805 379807 377810 379813 381813 383812 385811 386809 388806 389804 390802 390800 0.25 497654 494645 491639 487636 482634 475633 464634 455634 446636 442638 436642 430650 426657 425663 422667 418670 409675 399679 387684 379685 374688 372692 371696 368698 367702 359710 359715 362716 371713 376710 381705 384703 388701 397699 416695 426692 436691 445691 448692 451694 451698 442719 438731 436736 440743 448747 452746 459744 468739 473736 478731 481728 486721 491711 495697 498684 499677 499667 497654 0.25 518273 518268 515262 511258 509256 505258 503262 501265 498264 496262 493262 497269 499274 502278 508280 511278 514276 518273 0.25 529204 529199 528196 527193 526190 525188 524185 521182 518179 515178 512177 510180 511184 512185 514188 515190 517193 518196 519200 519201 521206 523207 524207 525207 527207 529204 0.25 502238 500235 499232 498227 495224 494226 495228 495231 497234 498237 499238 502238 0.25 488925 489916 487909 481902 477894 473890 470889 462888 457889 453890 446896 441899 439901 430907 424914 418932 419938 422941 422946 425953 426960 426967 429969 433970 438968 448966 462956 469951 475946 480941 482938 486930 488925 0.50 494662 491651 489647 486644 477641 466641 461642 454643 444647 440651 437657 436664 435667 433671 425677 426681 432681 442682 453683 458685 462687 464689 463693 461700 458712 453719 451726 452732 456733 463732 468730 478720 483713 486705 488699 491692 494684 495677 494662 0.50 472912 469913 466910 463910 459911 453910 450910 447914 444916 442920 443923 441928 438931 445933 451935 457938 461940 466938 468935 469931 469925 471921 472912 1.00 487663 484657 481653 477652 472652 469653 463654 460656 457658 455661 456666 459670 464673 467676 471678 475679 479679 485674 487669 487663 24HR QP VT 07/00Z 0.01 505663 495644 489636 486629 481623 475616 469613 453611 446610 443612 440615 435621 435625 434630 430635 427643 428647 430652 433657 437660 444666 446667 449673 448682 445693 443704 439712 437716 438719 438723 436726 431726 430732 433739 431746 430752 431757 438765 442762 446758 454756 458759 461763 467767 472766 476763 481756 488746 490741 493739 500739 503739 504735 511712 509689 507681 508676 505667 505663 0.01 522263 515254 512251 510245 509236 506230 503221 501214 498208 494203 494198 495193 499188 504186 514192 520196 523193 523187 524182 526173 527168 527164 523160 520156 517150 512147 508143 505142 498141 494139 490133 486130 481126 464131 464126 466123 468119 472115 475114 479110 478105 473101 473094 477090 479081 482076 486072 491070 496070 501073 506077 511087 515095 518101 523106 525108 528107 532110 535110 542108 544108 546104 546099 543092 538082 535073 534067 535062 534057 531050 529048 523034 520026 520015 519004 517997 513990 509988 503988 498991 494994 491996 488995 482994 476996 471996 457011 448031 453054 457051 462050 468050 469056 469065 470072 472076 470085 466089 462093 459095 456094 453090 446089 437088 433089 430092 430095 431112 435115 441115 443117 448119 461124 462129 461131 458134 458139 455153 452159 451162 451167 450175 453178 456184 459184 462182 462178 460173 459169 462169 467173 471173 474175 483182 485198 482204 477205 468209 465211 459211 455214 452219 452222 454225 458227 465230 466238 468245 471250 474256 476263 477269 479275 484284 490290 495295 500296 510298 0.01 511875 473828 463820 457817 452816 448814 447813 447808 445802 441797 439795 434796 431804 427810 421814 419812 419807 421802 424793 424783 418776 410777 404774 397774 391775 388776 385775 378772 375773 366780 361780 358778 354775 351773 348774 342775 335777 327789 322796 322805 325809 327810 334810 339815 343816 348815 351816 354824 356831 359833 361837 362843 359848 357850 356856 356863 356867 358871 363877 365880 365883 359891 358894 357899 355906 354914 357920 362924 367925 372923 374920 377919 382914 385913 394911 403900 411896 418894 439885 455887 461889 463890 466892 475902 486912 502903 505901 507898 508891 511875 0.01 456080 456076 453072 450069 449068 447067 444065 441065 439067 437068 436072 438076 439077 441079 443080 444083 447083 450084 453084 456080 456080 0.01 430937 428933 425930 421927 417926 411926 405930 404935 406942 410945 411945 414944 419946 422948 425948 428945 429941 430937 0.01 295820 294815 293810 291805 288803 276792 274788 275782 272777 266774 263773 258777 254781 252789 251796 247801 244808 242815 243820 246823 248825 252825 257831 263834 269830 273829 276830 283831 287829 292825 295820 0.01 315032 315029 312023 309021 305020 298016 292012 287010 281010 274016 273019 273024 276028 279031 290031 296036 298038 304039 309039 313036 315032 0.01 231973 234979 237980 243980 248980 252982 249986 242996 240000 241005 245011 250012 253009 258003 263999 268999 279990 282984 283978 281972 275967 258966 254963 250962 246962 238963 235964 232967 231970 0.25 502675 498660 495653 490645 485636 477626 470620 465618 460618 457619 453623 451627 450634 451640 454646 461656 466669 466675 464683 461691 459705 462713 469723 474728 477730 480730 484728 486725 492718 497712 500707 503696 504690 503680 502675 0.25 513266 512261 509255 507246 505239 501233 498225 495221 492225 492231 494240 492244 487242 484247 485252 486255 491269 498282 501286 504286 507285 509283 509278 508274 509269 513266 0.25 503257 503256 501252 500250 498246 497246 498246 499251 500253 502257 502258 503257 0.25 475862 474860 473859 470857 469856 467856 465858 465859 465862 466864 469864 469865 472865 475864 475862 0.25 436840 435835 432832 426833 420835 410842 407845 404845 407852 405861 394868 395870 400869 409863 418856 423848 431842 436840 0.25 274812 272809 269806 265804 262801 262798 260797 258801 256803 254807 255813 258816 261818 267817 272816 274812 0.50 500678 497668 494657 490649 485641 476630 472626 466623 462625 459630 457637 459641 462646 469659 473667 475677 476693 479702 482704 485706 490704 494698 498691 500683 500678 24HR QP VT 08/00Z 0.01 518756 514744 507739 501735 496728 491720 489717 491713 493705 494696 494688 492677 489668 485658 481648 476650 473654 468650 463652 460655 455661 451668 447675 444680 443684 445689 449690 448701 447708 445712 442710 441710 437706 435702 429694 416692 418684 418681 416676 411674 407673 398673 390675 376683 368688 362694 350704 341714 337720 334725 332731 332739 322751 318758 315763 315769 316773 320779 322781 327781 332775 339772 345770 351771 357773 363774 370771 374768 376765 378758 380753 384747 390739 392734 393730 404717 405709 411702 415703 414707 413715 415725 417728 421729 423728 426729 429730 433729 435736 431744 428753 422754 417750 414747 413743 412738 410736 406740 402746 399751 399753 399759 398762 397765 397768 399772 403773 403778 398785 388790 384792 382796 378803 376807 373809 371809 371802 368799 365801 363804 358819 356825 356834 355842 355846 357850 362854 364863 366872 365881 367892 368899 364911 363917 363922 364927 367932 378940 383941 391939 399938 403935 408933 411934 417939 424953 427959 433966 439971 444974 447977 448984 446995 450003 454012 458018 463025 465033 469040 473047 476050 479054 480058 482068 476081 461081 459072 456064 453056 450043 448036 446034 442033 439034 437037 436043 437049 441051 442053 444059 442064 437070 436076 440079 446083 448087 447089 441085 435089 428086 425089 424095 424100 421109 418130 416140 414147 413152 413157 414166 413173 415179 419181 421184 422189 424191 427191 429189 430181 430173 431168 426157 426147 428137 434124 439124 441126 442130 441133 438136 435145 434151 435156 438164 443170 447179 447181 444182 443186 443191 446195 445196 439198 445203 449202 451201 454197 455193 458189 463184 468179 475180 482184 484188 485191 483199 478206 474207 468210 461212 452213 446212 441214 438216 432219 427220 426225 426228 428236 429240 431245 435247 439247 452252 464256 470259 474261 477264 482272 487282 493287 499289 503290 507289 513284 517278 521267 520259 517251 516245 514242 511234 510228 506226 503216 502213 501209 503206 508203 513205 518211 524212 531204 534196 536187 537173 535163 534154 530145 526138 523135 522128 520118 523106 525091 525084 524077 524068 523063 518052 515042 513032 514029 517025 523020 528015 530005 530993 529985 528982 525976 522973 517969 513965 510961 510954 508942 506935 500926 496922 482915 476912 472907 464895 459890 453888 447884 442878 437871 429870 427868 424864 423862 424854 422847 417839 411835 410831 411829 412826 411821 410818 410809 412805 415800 422796 426790 427781 430774 434771 438770 443768 447765 449756 451747 449741 445736 443732 441729 440724 442718 444716 445720 446728 452732 457737 461738 463736 468737 472742 476750 485762 490766 496768 499769 504770 511769 517763 518756 0.01 418696 416695 414698 413700 415701 417697 418696 0.01 296803 292798 288796 283793 280790 275789 269790 263793 260797 255797 252799 249801 248804 249809 251814 255817 258823 261827 266830 271832 276831 279829 279822 281817 283813 284809 287809 293806 296803 0.01 309961 307948 302944 298941 284944 280948 274951 269952 264956 262960 260962 260966 266968 269971 269975 267981 260982 257985 252988 246991 242994 240999 240007 245011 251012 258004 269998 273997 279994 282991 285994 287998 291002 302004 306003 308001 309998 307994 306989 307984 306980 308975 309972 310966 309961 0.25 509274 513263 514257 512252 510246 509236 505231 503229 501224 499219 497215 494213 487211 480212 475215 475221 486228 486233 484233 477230 473231 471234 471240 472242 476248 481253 485258 488265 491271 496277 500279 503280 507278 508276 509274 0.25 502168 500162 496157 493155 492150 492144 488137 483133 480131 477132 472137 472142 470144 462141 457144 453148 449153 451159 453162 456163 464163 468167 472168 475168 482171 486174 493176 498174 502168 0.25 394692 391688 388688 381690 373695 366701 359707 356713 357720 360722 364718 371713 379708 385707 389705 391702 393696 394692 0.25 446109 444105 443105 441103 438104 436104 436108 438109 441110 444112 446109 0.25 422915 422908 421903 418892 414885 409879 405875 400866 398859 394853 390855 383855 378856 376860 374868 373876 373883 377902 382910 384917 390922 396923 401920 405917 409917 415918 420917 422915 0.25 369737 368731 366726 359723 352728 345733 341740 337745 333750 330754 330758 336759 341755 348749 356746 364743 369737 0.25 297970 298963 297957 294953 291952 288952 283955 281957 276960 275964 277967 279972 280975 283975 286975 291976 295973 297970 0.50 509255 509251 508245 506236 501229 499223 493216 486214 480217 487222 492227 494235 498245 503252 504254 509256 509255 0.50 403897 401890 396883 391878 387874 384872 380871 377878 377884 378889 380894 383898 386902 390909 396910 402905 403897 403897 $$