QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
550 PM EDT FRI MAY 09 2008
 
PLEASE TAKE OUR QUANTITATIVE PRECIPITATION FORECAST /QPF/ GRAPHICS
CUSTOMER SURVEY AT /USE LOWER CASE LETTERS/:                     
HTTP://WEATHER.GOV/SURVEY/NWS-SURVEY.PHP?CODE=HPCQPF             
 
FINAL DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION
VALID MAY 10/0000 UTC THRU MAY 13/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR
 
 
THE 18Z MDL RUNS WERE IN VRY GOOD AGREEMENT WITH THE 12Z RUNS..SO
MADE ONLY VRY MINOR CHGS TO THE PRELIM DAY 1 QPF.

DAY 1...

...SYNOPSIS...
HI LAT BLOCKG CONTS ACRS CAN...WHICH WL KEEP THE MAIN BELT OF LOW
AMP WESTERLIES ACRS THE CONUS. AMPLIFICATION OF THE PTRN WL TAKE
PLC THIS WEEKEND WITH SYS DEEPENG ALNG BOTH COASTS AND OVR THE
CNTRL U.S.. MDLS ARE AGN IN GD AGREEMENT WITH THE MAIN SHRT RNG
MASS FIELDS...BUT QPF...ALBEIT GNRLY LGT...IS DIFF IN THE GUID.

...OH VLY TO MID ATLC...
WEAK SHRTWV MOVG THRU THE OH VLY THIS AFTN WL CONT TO RACE EWD ON
THE HEELS OF THE EXITG STORM. THE UPR FLOW REMAINS BROADLY DIFL
WITH SOME DVRG UNER THE LEFT EXIT REGION OF THE STRNGTHNG SRN
STREAM UPR JET. MSTR REMAINS NR NRML VALUES FOR THIS TIME OF YEAR
WITH A TONGUE OF PWS NR ONE INCH...BUT THERE WL BE LITTLE IN THE
WAY OF FOCUSED LOLVL THERMAL FORCG/MSTR FLUX TO SUPPORT HVY RNFL.
MDLS SEEM SOMEWHAT OVRDONE WITH THE PCPN AMTS...CONSIDERG NONE OF
THE GEFS AND ONLY TWO SREF MEMBERS ARE SHOWG OVR ONE INCH OF PCPN.
THEREFORE...HAVE BACKED AWAY FM THE HVIER RNFL OVR WRN PA TNGT AND
EXPANDED THE LGT PCPN THRU THE REGION.

...SRN PLNS TO GULF STS...
COMPLICATED SCENARIO AS MDLS ARE SHOWG VRY LITTLE PCPN ACRS THE
REGION. LATEST WV SATL PICS CLEARLY SHOWS A STRNGTHNG SRN STREAM
JET ACRS NRN MEX/SWRN U.S. WITH A CLEAR VORT PUSHG ACRS NRN BAJA
THIS AFTN. THIS SYS/UPR JET SUPPORT WL APRCH THE SRN PLNS TNGT
WITH A DECENT AREA OF WAA/8H THETA-E ADV DVLPG OVR TX AND LIFTG
NWD THRU OK INTO MO BY SAT AFTN. MDLS GNRLY ARE TOO DRY WITH WAA
PTRNS OVR THE PLNS. DURG SAT AFTN THE ENERGY WL MOV A LITTLE
FARTHER EWD AND PROVIDE INCRSG UPR SUPPORT FOR MORE WDSPRD CNVCTN.
MDLS ARE SHOWG A WEAK BNDRY ACRS THE NRN GULF STS XTNDG WWD AND
INTERSECTG ANOTHER BNDRY PUSHG ACRS THE SRN PLNS. AHD OF THIS SYS
DEEP MSTR GULF WL POOL ALNG THE BNDRY WITH PWS XPCTD TO RISE TO
1.50-1.75 INCHES ON A MOD LLJ SAT AFTN. 8H MSTR FLUX ANOMALIEA ARE
FCST TO INCRS TO ARND THREE STDS ABV NRML. MDLS SHOW THE ATMOS
BCMG VRY UNSTBL WITH LIS DROPG TO MINUS 8-10 AND CAPES INCRSG TO
2-3K J/KG. WEAK CVRG IS SEEN IN THE GUID AS THE FNTL BNDRY/DRYLN
PUSHES EWD SO WITH THE FCST INSBLTY/CAPES AND APRCHG MIDLVL
SUPPORT...XPCT CNVCTN TO EXPAND DURG THE AFTN AND PSBLY BEGIN TO
ORGANIZE INTO A MCS THAT WL TRAVEL EWD ALNG/NR THE SFC BNDRY ACRS
THE NRN GULF STS. MOST MDL PCPN AMTS REMAIN VRY LGT ACRS THE
REGION...WHICH SEEMS UNLKLY CONSIDERG THE AMT OF INSTBLTY/WEAK
CAP. SVRL SREF MEMBERS ARE SHOWG SOME ONE INCH PCN AMTS. TIMG WL
BE CRITICAL...SO KEPT AMTS LGT/MOD...BUT GNRLY HIER THAN
GUID...SINCE THE MOST LKLY PD OF DVLPMENT WL BE THE LAST SIX HRS.

...NRN ROCKIES INTO NRN/CNTRL PLNS...
BROAD SHRTWV TROF OVR THE ROCKIES WL MOV ESEWD AND BEGIN TO DEEPEN
AS SHRTWVS PHASE AND THE WHOLE PTRN ACRS THE CONUS SHOWS
AMPLIFICATION. UPR JET SUPPORT IS SOMEWHAT DISORGANIZED ERLY IN
THE PD...BUT DOES SHOW AN UPR JET COUPLET DVLPG BY THE END OF THE
PD AS THE MID/UPR LVL TROF DEEPENS...WHICH WL SUPPORT INCRSG UPR
DVRG AND DEEP LYR LIFT. MSTR IS SOMEWHAT LIMITED IN THE GUID AND
THINK IT MGT BE STILL A LITTLE TOO HI CONSIDERG CNVCTN WL LKLY
FORM FARTHER S AND AT LEAST PARTIALLY BLOCK THE STGR MOIST INFLOW
INTO THE CNTRL/NRN PLNS. CNVCTN SHLD INCRS LATER THIS AFTN/EVE OVR
THE HI PLNS AS MIDLVL ENERGY WRKS EWD AND SUPPORTS INCRSG 8H
THETA-E ADV/CVRG. MSTR FLUX WL INCRS TNGT AS A 30-40 KT LLJ FORMS
THRU THE PLNS WITH MSTR FLUX ANOMALIES XPCTD TO BE NR NRML. STILL
SOME QUESTION TO HOW THE CVNCTN WL ORGANIZED AND THERE IS SOME
SUPPORT FOR TWO DIFF AREAS OF MORE CONCENTRATED CNVCTN. GNRLY
STUCK WITH THE OVRALL GUID PAINTG A SWATH OF MOD/HVY PCPN THRU SD
INTO SWRN MN. SREF/GEFS MEMBERS ARE VRY SUPPORTIVE OF SOME ONE
INCH RNFL AMTS THRU THIS REGION. A SCND AREA OF HVY RNFL IS PSBL
OVR NERN NEB WHERE THE MDLS SHOW STGR MSTR FLUX/THERMAL FORCG AND
THIS AREA SHLD HAVE SLGTLY HIER MSTR VALUES.

FARTHER W...OVR THE ROCKIES...XPCT GNRLY LGT PCPN AS THE
DISORGANIZED MIDLVL ENERGY CROSSES THE REGION. HVIEST AMTS SHLD BE
OVR THE PREFERRED HIER ELEVS.

...PAC NW...
DIGG GULF OF AK SHRTWV TROF WL INCRS ONSHORE MOIST FLOW TNGT INTO
SAT. XPCT GNTLY LGT PCPN OVR THE FAVORED CSTL RNGS/NRN CASCADES
WHERE UPSLOPE WL INCRS.
 
 
DAY 2...

A POTENT UPPER LOW WILL BE MOVING STEADILY EWD THROUGH THE PLAINS
AND MIDWEST THIS PERIOD.  THE ASSOCIATED OCCLUDED LOW WILL LEAD TO
A VERY WET SCENARIO ACROSS MUCH OF THE REGION...ESPECIALLY THE
LOWER GREAT LAKES...OH/TN VALLEYS...AND EVENTUALLY THE
MID-ATLANTIC BY LATE IN THE DAY SUNDAY.  PLENTIFUL AVAILABLE
DYNAMICS WILL LEAD TO A VERY LARGE AREA OF 0.50 INCH OR GREATER
QPF WITH THE POTENTIAL FOR LOCALLY EXCESSIVE AMTS FROM NERN MO
ACROSS N-CNTRL IL INTO NRN IN.  FARTHER SOUTH AND EAST EXPECT
CONVECTIVE DEVELOPMENT OVER THE APPALACHIANS AND ANOTHER LINE OVER
THE PIEDMONT AHEAD OF THE PROGRESSIVE COLD FRONT.

A PAIR OF SHORTWAVES WILL BE MOVING INTO THE PACIFIC NORTHWEST
BRINGING THE USUAL ARRAY OF OROGRAPHICALLY ENHANCED PCPN TO THE
CASCADES AND NRN ROCKIES.


DAY 3...

CLOSED LOW FCST TO MOVE SLOWLY THROUGH THE MID-ATLANTIC THIS
PERIOD LEADING TO THE POTENTIAL FOR VERY HEAVY RAINFALL ACROSS NRN
VA/MD/SERN PA/DE/SRN NJ.  MODELS ARE ALL FAIRLY SIMILAR WITH THE
LOCATION OF THE QPF MAX...BUT PER PMDHMD THE MANUAL PROG USED MORE
OF A BLEND OF THE GFS AND 00Z ECMWF.

THE AMPLIFYING WRN TROF WILL SPREAD MODERATE PCPN AMTS EWD THROUGH
THE NRN ROCKIES AS AN UPSLOPE FLOW REGIME DEVELOPS AFTER THE
FORMATION OF A LEE LOW OVERT ERN CO.


ECKERT/TERRY/MAUSSER

GRAPHICS AVAILABLE ON THE WEB AT WWW.HPC.NCEP.NOAA.GOV
24HR QP VT 11/00Z
 0.01 532205 533198 532190 530183 525173 519167 515166 514171 
      510170 506169 504170 501173 502179 503183 508192 513199 
      519205 521206 524210 528210 530208 532205 
 0.01 514286 517276 518265 517261 514257 512251 509236 506227 
      504220 499214 495212 490211 485210 481209 478208 474210 
      470211 467213 466217 478221 490229 488233 486233 482232 
      480228 477226 471228 464226 461227 459231 449235 443236 
      439238 439242 442243 446244 451243 455250 468257 477265 
      487276 496286 501290 504293 508294 514286 
 0.01 440641 438635 435634 428632 424631 421633 416635 412642 
      410649 407660 404676 401695 400713 400720 402725 406727 
      410727 414726 418723 424715 431699 433689 437681 440671 
      441666 441660 440651 440641 
 0.01 494036 492023 488014 483007 480995 478981 476964 481941 
      484927 484919 483910 480906 475903 472902 467905 463907 
      459911 448912 440909 436908 429910 424914 421915 412919 
      407919 404918 401917 397914 392907 385902 377899 368900 
      359900 356900 353898 350895 348890 349886 354882 360875 
      367867 372856 377845 387844 390847 393851 398856 403857 
      406857 409855 412853 414849 418841 419832 420828 420822 
      420817 420810 421805 422797 421793 422786 422779 420770 
      417762 413757 410753 407750 399746 392741 385735 378731 
      372728 365727 361729 357732 357736 358743 362748 364754 
      365761 367767 368779 371790 369803 367807 361812 357812 
      354810 354803 354798 354794 354790 352788 348786 347783 
      348775 349770 348766 347764 345766 342770 340774 337792 
      330794 327796 324800 318814 315823 316835 318857 319873 
      320878 319885 317904 316912 313920 304954 301963 297971 
      289986 287990 286994 287997 290001 293001 295999 301992 
      306985 311977 314973 320969 324969 325974 328981 331987 
      334989 342991 347990 350988 353984 354980 353974 355970 
      359969 363970 367972 373974 376971 381967 387967 391970 
      391978 392989 392993 394997 386014 391023 396028 398031 
      394031 386028 379023 373018 361005 357004 355007 357018 
      360025 363029 369036 383048 386053 389055 390058 386057 
      384056 381059 380064 381067 379070 378074 380077 386081 
      389085 392087 396088 400086 407080 413080 416078 419076 
      423080 421081 419086 419094 419099 418101 414101 412099 
      407091 406091 405095 406098 403106 397109 400117 407120 
      413121 418119 425115 434115 439116 442119 445123 446127 
      449132 455134 463131 480133 487130 490126 491120 491114 
      491108 486095 484090 482081 486070 490059 493046 494036 
 0.25 507278 506273 506272 504268 502266 501265 499262 497259 
      496258 494254 493253 491251 489250 488251 487256 488256 
      488261 489263 491266 492267 494270 496273 496274 499277 
      502279 504280 507278 
 0.25 434665 433661 429663 423670 419677 416684 414690 412701 
      411707 412710 414712 417711 420707 424700 426694 428685 
      432677 434670 434665 
 0.25 482033 482028 480024 475017 472008 471003 470995 468983 
      467975 468969 468944 467938 465936 461934 456935 453935 
      449933 441930 435929 426931 419936 413941 407946 404950 
      403954 402958 403963 405970 403975 403981 404986 407992 
      410998 413003 413006 412014 409023 411027 414026 419018 
      425003 427999 432997 436000 438004 440011 442024 444037 
      446048 448056 450057 452057 454055 456051 460049 470048 
      474046 479042 482033 
 0.25 410786 407776 403769 393759 391755 388754 383752 379757 
      378763 378774 380778 382787 382796 381798 383803 385807 
      388809 393812 398820 402825 404826 408825 410819 410810 
      411801 411790 410786 
 0.25 413072 413068 415064 412060 407057 404056 398053 395057 
      394061 392062 388065 387072 390076 392080 395079 400076 
      404072 410073 413072 
 0.25 390946 391939 389932 384924 381922 375920 366922 359924 
      353926 347927 341925 334918 330920 328924 325932 319950 
      315959 315962 320959 326955 330953 334954 337959 339960 
      348957 356958 366958 385951 390946 
 0.50 473029 469020 466004 464987 463976 462967 462961 463953 
      463948 462944 454944 445942 441939 436937 430938 424940 
      417948 414953 414961 411966 410968 409972 409980 412988 
      414992 418995 421993 425989 435983 438984 442988 445003 
      447020 446035 448040 451043 453042 460040 467038 472034 
      473029 
 0.50 405789 404785 402782 401779 398776 397775 394774 391775 
      391776 389779 389781 389785 391788 392789 393791 396793 
      399796 400796 403795 403794 405790 405789 
 0.50 383940 380933 376931 373930 367929 362931 357934 355939 
      356946 359949 365950 370947 373946 376945 378944 381943 
      383940 
 1.00 460009 459997 457989 456985 458980 457968 456960 453958 
      444956 441958 439963 439967 443973 446976 449979 452984 
      454985 454989 452993 451001 453010 455015 458018 460009  
 
24HR QP VT 12/00Z
 0.01 550164 549155 548147 543134 537121 532116 526101 526092 
      525077 523062 515045 507041 499039 494031 489023 480032 
      476046 478062 480079 460081 447081 441091 432092 428108 
      433124 437140 432150 434157 443171 439179 434190 438199 
      431205 424219 407235 404247 411255 428254 448258 471264 
      490278 506288 509289 512287 
 0.01 497904 492896 489893 483891 476889 473886 470882 464871 
      459858 454854 444854 437858 434857 438851 444838 445819 
      435789 428778 422767 410750 404743 397735 390730 382725 
      372721 364719 355718 347719 338723 333728 328738 324747 
      321756 318768 316772 317776 318786 313792 310797 309801 
      310807 308811 299815 296817 294821 292825 292830 294837 
      294847 295857 295868 294877 293886 290895 285915 282933 
      279951 278955 277962 278967 282969 286969 289970 290974 
      294976 300976 307974 314968 320961 324955 327946 330941 
      332940 337942 341942 348943 355942 358942 363942 369943 
      372945 375954 380962 387968 395973 399976 406977 411972 
      416971 425973 428973 433975 437975 441978 452977 458976 
      464972 470964 477952 482940 485930 489921 492916 495914 
      497908 497904 
 0.25 536206 538190 536176 535169 533165 529159 523154 515150 
      510148 505147 500145 496142 488134 484133 478133 474139 
      471145 466147 462152 461156 458162 455165 454172 453177 
      452182 452186 454188 457188 461186 469180 473178 478177 
      484181 487186 490197 489202 486206 478209 469213 465216 
      461216 450216 442218 439221 439225 443228 450230 458230 
      468228 477232 489238 501255 504258 507260 510260 511257 
      511252 510246 506233 502223 499212 499208 502206 509208 
      518214 522216 526216 530215 533212 536206 
 0.25 474929 473924 471922 465919 461919 453920 446920 442919 
      439916 438908 438897 437892 435887 431882 429873 428862 
      431843 431835 431826 429815 426805 423799 418792 409781 
      399772 394766 389760 385754 382751 376747 371744 365741 
      357741 348745 338754 336759 335762 335768 333776 329782 
      322793 320799 319804 314817 310823 307829 309837 312842 
      317846 322847 327851 329860 334881 336890 338899 340907 
      343911 349915 353920 357926 362930 366931 370930 374927 
      381924 386926 388928 389933 392942 399947 405950 416952 
      426958 432962 438963 445962 453958 460952 466946 471938 
      474929 
 0.50 529199 529193 526187 524183 518178 510173 503164 500162 
      493160 488160 482158 476157 472159 465169 460175 461178 
      464175 470168 475165 480168 489168 493171 497176 499181 
      503186 511189 519196 524200 528201 529199 
 0.50 465932 461928 452928 444929 435932 431933 427936 424942 
      424947 427953 432956 438955 444953 451948 457944 463939 
      465935 465932 
 0.50 425845 425836 423829 418820 412808 409802 405797 398788 
      394779 392771 388766 380758 374752 367749 357749 351753 
      347757 346761 346769 342776 336785 329792 324796 323800 
      322809 321816 322822 321830 322834 327834 330838 331850 
      336864 340876 342882 343889 345896 348901 351901 353899 
      359895 362894 367893 372895 375897 381905 388912 392926 
      394931 397936 401939 406938 412935 416932 418926 419919 
      420907 422895 425884 425876 423866 425845 
 1.00 418849 414847 412851 408850 403856 403869 403878 401886 
      394895 393901 395911 396919 397924 399928 403929 408925 
      412912 415898 417884 418868 419855 418849 
 1.00 344862 349873 355868 360860 366838 374830 389828 398827 
      400817 389811 373811 362816 356827 350827 345823 347810 
      349801 357798 367796 377797 381784 381769 368760 358766 
      347783 343792 336796 331798 328803 328806 333815 338822 
      339827 338832 338843 340852 344862 
 1.50 400922 402925 404923 405919 406912 407907 407902 406901 
      403902 400909 399916 400922 411875 411874 410873 410874
411875 411875 
 1.50 353839 352839 349839 346841 346843 346845 348847 351846 
      353843 353842 353839 
 
 
24HR QP VT 13/00Z
 0.01 387070 379086 378104 391107 390110 385114 375122 378137 
      390151 406156 413171 425188 434185 436188 434192 436199 
      444202 458190 465178 473182 488198 508228 523229 537211 
      544186 538153 526129 512117 497103 491080 492065 496064 
      500079 509087 519067 519026 517996 508973 496950 493935 
      487926 484922 479919 472916 464914 458914 452914 447917 
      444921 440932 439945 439952 440961 442979 443995 445008 
      447020 447028 444030 434026 428025 422028 416034 409045 
      397056 392062 387070 
 0.01 451857 483843 495817 492795 484786 466773 449781 433771 
      435755 439740 440733 441724 441713 434682 417674 398665 
      385669 369689 358697 338704 322729 311762 300793 294816 
      301833 311838 323825 335804 349796 355801 353819 344838 
      345851 359866 381874 394876 401877 411874 421870 431866 
      441862 451857 
 0.01 507261 489234 474235 476249 489272 502283 509277 507261 
 0.01 443217 431221 424233 434246 448244 460242 455234 454229 
      461228 472227 475218 468216 449215 443217 
 0.01 269804 268795 264793 262794 257797 254804 253811 253817 
      256826 258829 261830 264827 266822 268814 269808 269804 
 0.25 533190 533182 533178 528169 520156 509143 504137 498133 
      492127 488121 485118 481118 476124 474133 475136 477141 
      485152 493167 499173 507177 515181 521186 526191 531192 
      533190 
 0.25 429701 427698 422695 419694 413696 409699 405703 401708 
      395708 388708 383710 378713 369717 363721 355728 352731 
      350736 350745 352754 356764 362773 368781 372790 373797 
      372801 368810 363816 361820 360825 360829 362834 369840 
      375843 383845 392846 401846 408846 417847 426846 436840 
      443836 447831 448826 448821 446818 442814 439809 434802 
      429792 427781 426767 425746 429724 430714 429703 429701 
 0.25 483090 485084 484078 482069 478067 473070 469076 468078 
      464078 460074 456069 451065 447064 443064 438068 438076 
      441082 442084 442089 435096 431102 427108 424113 422119 
      425124 429128 434132 436135 436140 435146 434151 429154 
      428156 427161 431165 437164 444163 450163 454159 458154 
      460152 460146 460139 461135 463127 467122 469113 470106 
      473099 478095 483090 
 0.25 398086 402087 407083 410077 410073 408069 404068 398071 
      394076 393081 395085 398086 
 0.50 500153 502157 506159 508160 509158 507154 502148 499149 
      500153 
 0.50 492138 489135 486137 487140 489143 491144 493145 494142 
      492138 
 0.50 423719 419707 414709 409718 396719 386721 378725 372730 
      367736 364743 365751 366758 370768 373775 381789 387799 
      391806 391811 382808 377812 370817 367823 369826 372827 
      388823 394822 397822 401820 405818 406812 405805 410802 
      417801 420798 421793 422785 422775 422767 420749 419738 
      420732 423719 
 0.50 459110 460103 459097 456092 451091 449093 444097 438102 
      433108 435116 441121 445125 449133 451129 452126 453122 
      457114 459110 
 0.50 446146 447150 450150 453146 452141 451135 450135 447142 
      446146 
 1.00 413755 412745 409737 403733 398732 393734 390736 380746 
      376752 375757 376767 380774 383780 388786 396790 401792 
      406792 410792 413790 415784 415771 413755 
 1.50 411773 407769 406764 408755 405747 402743 396744 393744 
      389746 386750 384756 382760 381765 382769 388778 393781 
      399784 404785 408785 410782 411778 411773 
 2.00 400753 399755 398758 400761 403759 404756 403753 400753