QUANTITATIVE PRECIPITATION FORECAST DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 601 PM EDT SUN MAY 01 2011 FINAL DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION VALID MAY 02/0000 UTC THRU MAY 05/0000 UTC REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR UPDATE... THE FINAL DAY 1 QPF AXIS WAS SHIFTED NWWD INTO CNTRL TO NWRN AR...SERN MO AND THE LOWER OH VALLEY REGION FROM THE PRELIM PSN APPROX 60-80 NM FARTHER TO THE SE. ONLY THE HI RES RUNS..WHICH HAVE NOT BEEN VERIFYING VERY WELL...LIKE THE FARTHER SEWD SOLN. LATEST RADAR TRENDS ALSO SUGGEST PCPN REMAINS MOSTLY POST FRONTAL. ORAVEC ...DAY 1... ...SYNOPSIS... MID/UPR FLOW REGIME SHOWS SPLIT FLOW OVR THE CNTRL U.S....EMBEDDED WITHIN A DEEP LRG SCALE TROF. STG SERN U.S. RIDGE WL REMAIN INTACT...WHILE SHRTWV ENERGY PUSHES INTO THE PAC NW AND BEGINS TO BREAK DOWN THE INTERIOR WRN U.S. RIDGE. MDLS ARE IN GNRLY GOOD AGREEMENT WITH THE OVERALL PTRN. SOME SMALL SCALE DIFFERENCES WITH SHRTWVS AND ASSOCD PCPN OVR THE SRN PLNS INTO OH VLY IS SEEN...BUT THE DIFFERENCES ARE NOT AS LRG AS PRVS DAYS. ...LWR GRT LKS SWWD INTO THE SRN PLNS... FNTL BNDRY PUSHG THRU THE GRT LKS AND EXTENDING SWWD THRU THE LWR OH VLY AND TX IS FCST TO SLOW ITS EWD PROGRESS AS THE NRN PLNS VORTEX LIFTS INTO CAN...WHILE THE 4 CORNERS CLOSED LOW EDGES SLOLY EWD INTO THE SRN HI PLNS...AS THE SERN U.S. RIDGE HOLDS STG. MOST GUID IS ON THE SAME PAGE WITH A RIBBON OF HVY RNFL FM NRN TX INTO THE OH VLY...WITH LGTR AMTS INTO THE LWR GRT LKS. ISSUES ARE WITH THE SMALLER SCALE SHRTWVS AND PSBL FEEDBACK SEEN IN THE GUID THAT IMPACTS THE FCST. THE UPR FLOW WL REMAIN DIFL THRU THE PD...WITH AN INITIAL UPR JET COUPLET WORKING TWD ENTRNC REGION UPR JET SUPPORT. MDLS SHOW THE ATMOS ALNG/S OF THE SFC BNDRY WL REMAIN MARGINALLY UNSTBL DUE TO SOME MIDLVL WARM AIR IN PLC...SO MOST OF THE PCPN SHLD BE VRY CLOSE AND N OF THE FNTL BNDRY...ESPCLY SINCE THE BNDRY WL STALL. MSTR REMAINS DEEP WITH PWS 1.50-1.75 INCHES ALRDY IN PLC OVR THE ARKLATX WITH MSTR XPCTD TO LIFT NEWD THRU THE PD AS A MOD/STG LLJ THAT IS ALRDY IN PLC HELPS TO ADVECT MSTR NEWD. MDLS/SATL DERIVED DATA SHOWS A STG LINK TO EPAC/GULF/CARIBBEAN MSTR SO MSTR REPLENISHMENT IS NOT A QUESTION AT THIS TIME. LATEST SREF/GEFS/EC ENSEMBLE GUID ARE ALL SHOWG STG SUPPORT FOR A RIBBON OF HVY RNFL FM THE ARKLATX NEWD INTO THE LWR OH VLY...WITH STG SUPPORT FOR ADDTNL WIDESPREAD AMTS OF 3-5 INCHES. ...CNTRL/SRN ROCKIES... 4-CORNERS CLOSED LOW IS FCST TO BEGIN MOVG EWD LATER TNGT AND CONT TO PROVIDE SOME LRG SCALE LIFT ACRS THE REGION. MSTR CONTS TO DECREASE...SO PCPN AMTS WL REMAIN LGT. ...PAC NW... GULF OF AK VORTEX AND ASSOCD TROF WL PUSH INTO/ACRS THE REGION WITH STG HGT FALLS...ESPCLY LATE TNGT INTO MON. MDLS SHOW THE SRN END OF THE TROF WL BCM NEG TILTED THAT WL ENHANCE UPR DIFL/DVRG ACRS THE REGION. EPAC MSTR IS NOT VRY IMPRVS...BUT MDLS ARE SHOWG SOME ONSHORE FLOW THAT WL AT LEAST PROVIDE SOME LOLVL MSTR...WHILE ALSO BOOSTING UPSLOPE ALNG THE CSTL RNGS/CASCADES. XPCT PCPN AMTS TO REMAIN LGT...EXCEPT FOR SOME MOD AMTS PSBLY OVR XTRM NWRN WA AND THE NRN CASCADES. DAYS 2 AND 3... ...LOWER MS VLY NEWD TO THE MID-ATL/NORTHEAST... ANTICIPATE ONE MORE DAY OF LINGERING MDT/HVY...AND IN SOME LOCALES...EXCESSIVE RAINFALL AMTS FROM THE LWR MS VLY INTO THE OH/TN VLYS ON TUES BEFORE THE PHASED AMPLIFIED UPPER TROUGH SWEEPS INTO THE ERN SECTION OF THE COUNTRY ON WED. THE QUASI-STATIONARY FRONT NEAR THE LWR MS VLY WILL BE FINALLY ON THE MOVE ON TUES... AS SHORT WAVE DYNAMICS OVER THE SRN PLAINS BEGINS TO INTERACT/PHASE WITH DIGGING NRN STREAM TROUGH. FAVORABLE MID/UPR LVL FORCING ALONG WITH DEEP SWLY FLOW SHOULD KEEP THE THREAT FOR HEAVY RAINS AND POSSIBLE TRAINING ACTIVITY EARLY IN THE FCST PERIOD/TUES NEAR THIS BOUNDARY OR FROM THE LWR MS VLY INTO THE TN VLY. THEN TUES AFTN... THE TWO STREAMS WILL COMPLETELY PHASE ALLOWING THE SURFACE FRONT TO BECOME MORE COLD AND SLIDE EASTWARD FROM THE ERN GRT LAKES/OH VLY SOUTH INTO THE ERN TN VLY AND DEEP SOUTH. THE MODEL GUIDANCE HAS SHIFTED SOME FROM LAST NIGHT IN REMAINING PROGRESSIVE WITH THE UPPER TROUGH AXIS ON WED AS IT PROGRESSES DOWNSTREAM FROM THE MIDWEST INTO THE EAST. THIS SHOULD ALLOW A SURFACE LOW TO DEVELOP OVER THE NRN MID-ATL REGION AND SLIDE NORTHWARD TOWARD MAINE AND THE SURFACE COLD FRONT TO SWEEP OFF THE EAST COAST. THE RESULTANT SHOULD BE MDT TO HVY RAIN FROM CENTRAL PA/NY NEWRD THROUGH NRN NEW ENGLAND WITH MORE SCATTERED TO ISOLATED PRECIP FROM THE MID-ATL INTO THE SOUTHEAST. OVERALL HPC FAVORED A BLEND OF THE OPERATIONAL GFS AND ECMWF BOTH DAYS FOR NOT ONLY MASS FIELDS BUT QPF. ...PACIFIC NORTHWEST TO THE NORTHERN ROCKIES... A PROGRESSIVE PAC SHORT WAVE TROUGH STARTING OFF OVER THE INTERIOR NW/NRN ROCKIES WILL STREAM EASTWARD AND LOWER HEIGHTS OUT INTO THE NRN PLAINS TUES AND WED. SOME OROGRAPHICALLY FOCUSED QPF IS EXPECTED TUES ACROSS THE NRN ROCKIES... SPECIFICALLY THE ID BITTERROOTS. THIS ACTIVITY SHOULD TAPER OFF ON WED... AS RIDGING QUICKLY BUILDS ALONG THE NORTHWEST COAST TO SHUT DOWN THE PAC MOISTURE TRANSPORT INTO THE REGION. THIS WILL SHIFT THE SYSTEM OUT INTO THE NRN PLAINS WITH VERY LITTLE AVAILABLE LL MOISTURE CONTENT TO WORK WITH FOR LIKELY SCATTERED SHOWERS AND QPF GENERALLY LESS THAN A .25 INCH. ECKERT/MUSHER GRAPHICS AVAILABLE ON THE WEB AT WWW.HPC.NCEP.NOAA.GOV 24HR QP VT 03/00Z 0.01 504716 500707 497701 488703 468708 459711 449715 440719 430723 420729 413736 408741 404745 399754 383789 373808 362825 349841 344847 338855 315886 309892 305900 302917 300923 299928 295936 292947 293951 297951 300950 300956 299960 300966 302971 301976 295981 290984 288989 283996 281000 284004 289012 296018 303021 309022 313022 320023 327024 333022 336020 339015 341010 342005 344995 347984 350979 353977 363962 370957 378949 381944 385941 390933 399916 408899 412887 416878 425857 433841 444822 451811 455805 457803 466794 473785 481775 487767 494756 499747 500738 502728 504716 0.01 534205 535199 535193 533185 531178 527172 524166 520163 510156 504155 500155 491154 485152 475147 465144 463144 460146 457151 450163 447178 442181 440186 440190 442193 449195 453197 455193 459186 463183 464181 468182 474183 476189 478197 476202 471206 463209 458211 455214 452213 443215 437219 435221 436224 449227 453228 453230 450230 437234 430240 426246 425252 428256 433259 441261 447266 449271 451276 453278 457282 463285 470287 475288 487292 499293 505290 509288 513285 516282 517277 519270 521260 521251 520242 517235 514229 508219 506215 507211 513213 517216 523218 527217 531214 534205 0.01 451076 450074 448072 447071 444070 441068 439072 441074 444076 447079 450080 451076 0.01 445109 444107 441106 438106 435106 432106 429106 426106 423106 421107 423109 426109 429109 432110 435110 438110 441110 444110 445109 0.01 410072 411062 409054 404050 401049 391039 388039 386043 380043 375039 370029 365026 361026 356030 352034 346043 341045 335046 328047 324047 322049 328058 334060 341061 343064 342068 344070 347070 351068 355066 358068 368072 372076 375083 381079 386075 389074 392072 396071 398076 401073 406072 410072 0.01 273799 272799 270797 269797 265796 263796 260797 257798 255799 252801 250802 250803 248805 247807 249808 252808 254807 257805 259804 262803 264802 267802 268802 270801 273800 273799 0.25 488743 488737 486734 482733 475734 466738 457743 446748 439749 432749 427750 420757 414764 403781 400787 398796 397800 396804 391812 349864 344871 339877 327890 322895 319899 317903 315909 315910 319912 329908 331910 330912 329915 322932 320948 315960 310969 307976 303985 299991 298994 298000 300002 304003 310004 314005 319005 324002 327999 332994 337987 341980 349968 360956 371944 376937 381930 387917 390908 394899 402884 409866 416849 420834 423823 426815 432806 439800 446792 451785 457777 462773 480757 484752 487748 488743 0.25 516267 517257 515248 511238 508230 499216 494212 488211 479212 478217 483219 487223 492230 492233 491239 484241 480246 479253 485273 490279 495283 501284 507283 514275 516267 0.25 517191 514187 512185 511184 509182 506181 503183 506187 506188 508190 511192 514193 517191 0.50 513271 515261 515255 509245 508239 506235 503232 502228 500223 496219 493222 494226 500235 502239 504248 500253 494250 491249 488251 488260 490266 492271 496276 501280 508279 511275 513271 0.50 473753 472753 470755 467756 464758 462760 462761 462760 465759 467758 470756 472754 473753 0.50 413838 411829 409821 407819 404818 398822 386837 373854 366862 359869 352876 347884 344895 341904 337913 332923 328931 326939 322950 319960 315969 311977 308986 307993 310998 313000 315999 321996 324993 347965 355957 362949 374935 379927 384917 389907 392899 395887 399878 407859 411847 413838 1.00 402854 401848 398844 395843 391846 381854 371866 364877 356889 348902 341913 335926 326952 322967 321974 325976 331974 337970 343965 346961 364940 369935 374929 380918 385901 390889 396874 401859 402854 1.50 395865 395859 393855 391853 388855 381862 376867 372873 366882 360892 354900 346911 340920 336931 332942 326965 326969 329970 335967 339965 343961 351951 358944 366935 373925 376920 378914 381903 385890 390878 394870 395865 2.00 391870 390866 387865 383869 375877 369885 363894 357903 350909 343919 338928 335939 333948 331961 332964 335963 340960 344955 350949 358942 365934 370925 374914 377902 381892 389873 391870 3.00 365926 364915 362912 359911 350914 346920 343924 339932 338939 338946 339950 342952 347947 352942 356941 360938 362934 365926 4.00 357935 356931 356932 356935 357936 357935 4.00 353925 353922 352921 351922 349924 347926 346927 344928 343931 342934 342935 342938 343939 346938 346937 348934 349933 350931 352929 353926 353925 24HR QP VT 04/00Z 0.01 505673 500670 495669 491669 487671 484672 479675 476678 472675 469664 464658 458661 452665 447672 445676 434698 427709 422719 415733 407745 402755 397765 393771 390774 384783 380787 375792 368800 355809 351811 347814 344817 337824 329831 321836 311842 304851 302861 293871 289875 287880 279898 275905 271912 263932 257943 251952 243966 239969 237974 237981 243984 245986 244989 242001 242013 242018 243021 248022 251019 252015 256006 258002 260998 266992 292989 300987 305984 311981 316979 334970 353960 362952 369946 377936 384924 389915 395903 398900 399894 402885 414863 428840 440821 446812 451802 458788 461783 464777 468744 469737 470734 473733 483733 488730 490727 497716 500709 502704 503698 505693 507687 506678 505673 0.01 534210 535203 535196 533188 531179 526171 523165 519160 515156 512149 511144 512138 515132 518123 519117 515099 512082 511072 509063 505054 501049 494050 493051 492057 494072 485081 480088 477096 476102 470105 467105 463104 459099 455093 453088 455083 456076 454071 453064 452062 448059 443061 440066 439071 440076 444081 447084 447086 447089 443090 434091 431091 427088 425083 422079 417076 412076 410085 411090 413093 415090 419091 423093 425096 424099 421104 417107 415113 417117 420123 420127 419129 417140 416149 417158 423166 423172 424175 431177 443187 449190 456189 461189 465187 471184 477185 489194 495195 501198 508202 512206 517209 520211 526213 530213 534210 0.01 521270 522260 520253 516243 506221 500210 497205 493203 489199 484200 480201 477203 471204 467206 459210 451215 443218 439220 440224 450229 452234 452240 451244 452248 455251 461254 468255 473256 478259 490275 498287 505293 509292 512290 0.01 440129 440128 437127 434127 431127 431128 429131 428133 427135 426139 427143 430140 431140 433137 436136 438132 440130 440129 0.01 268802 263798 257797 251797 246801 243807 242813 243821 246823 248822 253819 256813 258808 264806 268804 268802 0.25 518273 518263 517258 515253 510246 507244 503246 502252 500256 496257 493258 492262 495268 499277 504281 510283 514281 516277 518273 0.25 522187 521182 516177 510172 508168 505161 503151 498144 489139 486139 483142 480145 474146 463146 456148 451150 448154 446159 449163 452163 456168 460171 463168 472167 475167 480168 486173 494178 500182 511188 520188 522187 0.25 456713 454708 449710 441716 436720 434725 429732 422747 417753 411760 406767 403774 395790 388802 378814 348837 341849 337853 330858 323862 318867 312873 309879 307887 296897 298902 304902 312901 317903 313911 305920 295928 293932 293937 290944 289948 290952 294954 298955 300956 300959 302963 304965 307966 311966 315965 322960 325959 330959 335957 343953 348951 355946 360941 364937 369930 373924 376915 379907 382899 385892 392881 397874 402866 410850 423823 427815 431808 435799 438788 439779 441770 445757 449745 453731 455721 456713 0.25 497222 497218 496217 494213 492212 491211 488209 486208 482209 479210 476212 473214 472215 469218 472221 475221 478221 481222 484223 486224 489225 492226 494226 495226 497222 0.25 500109 499104 496102 494104 493108 492113 493115 496116 498113 499111 500109 0.25 286971 285969 285968 282968 279968 277969 276970 274973 276976 278976 280976 283975 285972 286971 0.50 516272 516267 516266 515262 514260 512256 509259 507263 507264 505267 505272 506273 508276 511277 514276 516272 0.50 491220 490219 488215 485214 481217 484219 487220 490221 491220 0.50 442746 441740 439737 436737 433740 426752 420763 412771 407783 405789 401795 396804 390812 380822 369831 353844 343866 339876 337887 335893 333898 327908 322916 320926 313934 312939 316941 321940 326941 336943 343944 346944 349942 353938 357932 364926 369918 372906 379893 385884 390876 397867 404855 413833 418823 424810 429800 431787 433776 434768 437762 440753 442746 0.50 315960 317957 314954 311955 309958 308958 309961 309962 312962 315960 315960 1.00 423787 423780 419780 415788 411802 406810 400818 396824 391828 374838 367844 363849 358865 352877 349885 347895 345901 341907 334920 336922 343919 351915 358910 367900 378886 384876 388867 392858 399847 414817 420799 423787 1.50 389847 383844 380843 375847 373851 368863 363875 362881 362887 356897 350905 354905 360900 362897 371888 374883 376879 380866 386856 389847 24HR QP VT 05/00Z 0.01 496649 484628 480623 477624 470627 460632 457634 455637 451647 444660 439668 433676 424683 418686 400695 389699 380703 373706 367708 363712 358717 350724 338738 325754 308781 308785 310790 316791 325790 331790 335791 336795 335797 331806 329813 323819 318825 311831 304832 298833 294837 291844 288852 284860 283866 283871 285873 294876 296878 301877 306876 309880 313889 316892 319894 323893 327890 333885 360859 373847 379843 389839 408839 416839 424837 430831 436823 449810 456802 464792 469784 473776 476765 479754 481748 483744 486735 494714 497704 499689 499678 498667 496649 0.01 518273 520267 520259 518252 514250 510250 503252 497255 492257 487264 484277 487283 489284 492289 496291 503289 510285 514281 518273 0.01 509091 508086 503082 500081 494081 491082 488086 485094 488101 490104 496104 500104 505100 507095 509091 0.01 505976 504966 503959 500953 496949 487941 477933 473931 468931 459936 449945 441953 437956 431956 423953 418950 414949 410950 406954 403959 402967 405976 409985 410989 410994 409001 409005 410009 414014 417017 419020 419024 418030 415037 413043 413052 409053 405054 401057 399062 398071 398075 401079 404080 407082 410080 415078 419073 421072 430080 437089 435105 435112 437118 441119 444118 448114 454105 454100 454095 452089 455072 455063 456056 458051 458047 460043 467034 476025 480019 482018 483023 484030 487037 491037 493029 493022 494017 498015 501013 501010 501007 498001 498998 503987 505976 0.01 495226 497222 497218 494212 491209 489206 486206 481209 476209 473211 467212 466217 469220 475221 478220 484219 489224 492227 495226 0.01 500136 501132 499127 495126 487126 478123 471128 463135 460138 456143 454147 453155 455160 461164 466163 472163 475161 480164 484165 487165 489157 491153 492148 492144 495139 500136 0.01 479155 479151 477146 474146 471145 473150 474150 476155 479155 479155 0.01 437004 436001 433002 432004 431006 429009 428010 427013 428017 431016 434012 436008 437006 437004 0.01 297812 295807 293803 289803 282803 277803 269805 263804 261801 258800 254801 251805 251810 253812 258809 262810 262814 256816 256820 261826 268823 274824 280823 288822 294822 296820 298816 297812 0.25 493668 492662 491656 488650 485646 480643 475643 469645 463650 453664 434690 424704 419710 416719 414733 414738 413741 409747 406752 402760 398765 394767 390768 383769 382761 388752 393748 396745 397740 389741 384743 371746 365746 360747 356750 354753 354757 360765 363770 366774 357784 353791 351798 350811 348819 348826 349835 350839 353842 360839 367834 378825 397804 404800 410799 417800 424799 431797 437793 443788 449782 458771 463764 467757 474741 480727 487709 490701 491693 493679 493668 0.50 489666 488661 486655 481651 478650 474650 469653 462659 459664 449679 441692 437698 434706 432720 433724 432728 428736 421746 410759 407764 404770 403774 403778 409783 419784 425783 433779 444771 451766 457759 465747 472732 478719 481711 484701 487688 489677 489670 489666 0.50 368818 367817 366815 365812 362812 360814 359818 359820 359822 360823 362824 363824 365823 366823 368820 368818 1.00 484671 482664 479660 475660 472661 466667 459678 451694 450699 450705 452712 453716 452721 449725 444734 438741 435745 436749 438752 441753 446753 449751 455746 461738 467729 471720 476710 479700 482691 483680 484671 1.50 480685 479680 478677 476673 473672 471675 469679 467682 465686 465687 464692 464693 465697 466701 468702 470703 472703 474700 475699 476697 478692 478691 479687 480685 1.50 465721 462720 459722 457725 455728 455729 453732 452735 452738 451740 452740 455738 456737 457735 459732 461729 461728 463724 465721 $$