FXUS04 KWBC 111939 PAA
QPFPFD
 
QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
338 PM EDT SUN APR 11 2004
 
PRELIM DAY 1 AND DAY 2 QPF DISCUSSION
VALID APR 13/0000 UTC THRU APR 14/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR
 

...DAY 1...

AS HAS BEEN THE CASE FOR THE PAST FEW DAYS...THERE ARE SOME LARGE
DIFFERENCES BTWN THE ETA AND GFS MASS FIELD DETAILS ON THE
HANDLING ASPECTS OF THE DVLPNG CLOSED UPPER LO OVR THE CNTRL U.S.
AS NRN AND SRN STREAM ENERGY PHASES.    FOR THE MOST PART...THE
MANUAL DAY1 QPF LEANED TOWARDS THE ETA MASS FIELD SOLUTION FOR
ITS DETAILS GIVEN GFS FEEDBACK PROBLEMS THAT APPEAR TO BE
AFFECTING ITS FCST DOWNSTREAM IN BOTH TIME AND DISTANCE.   THAT
BEING SAID...TRIED TO KEEP THINGS SIMPLE AS EVEN THE ETA IS
SHOWING
LARGE DIFFERENCES IN QPF PLACEMENT EVEN IN THE VERY SHORTER
RANGES.  

...ERN HALF OF THE NATION...

THE MODELS ARE IN...AND I USE THIS VERY LIBERALLY...GNRL AGREEMENT

THAT THREE PRIMARY SWATHS OF SGFNT PCPN WILL OCCUR DURING THIS
PD.   THE FIRST SWATH WILL BE FM VICINITY OF THE LWR MS VLY NEWD
ACROSS THE UPPER TN VLY TOWARDS THE CNTRL APLCNS.   THE MODELS
EACH INDC THAT A MID LVL CLOSED LO CNTR WILL EVOLVE OVR THE LWR MS
VLY BY TMW MRNG AND THE STG ISENTROPIC ASOCTD WITH THIS PROCESS
WILL BE THE TRIGGER FOR THIS AREA OF PCPN.   THE GFS SEEMS
INITIALLY 
OVERDONE WITH SPINNING UP THIS CNTR AND HENCE BELIEVE ITS SWATH
OF QPF IS TO FAR NORTH.   THE ETAS QPF MAY ALSO BE A TAD TOO FAR
NORTH AND PREFERRED TO STREAK MORE PCPN OUT TO THE NORTH AND
EAST GIVEN THE STG BAROCLINIC ENVIRONMENT IN PLACE AHEAD OF IT.  

ANOTHER AREA OF SGFNT PCPN WILL OCCUR FM THE CAROLINAS NWD INTO
THE MID ATLC STATES WHERE VERY HI PWS  WILL SUPPORT A STG WAA
PCPN  AS DEEP-LAYERED SLY FLOW DVLPS IN ASOCTN WITH THE DPNG
CNTRL U.S. VORTEX.   BOTH THE ETA AND GFS QPFS ARE IN THE SAME
BALLPARK HERE AS STG UPPER LEVEL FORCING ASOCTD WITH VERY FVBL
DIV FLOW ALOFT FCST TO AID THE LIFTING PROCESS. 

OVR FL...VERY HI PWS WILL BE IN PLACE HERE TO SUPPORT WHAT SHOULD
BE WIDESPREAD HVY CNVCTN ACROSS THE STATE.   NOT VERY
COMFORTABLE PICKING OUT A SPECIFIC MID LVL TRIGGERS FOR THE ACTVTY
WHICH COULD INCLUDE THE REMNANTS OF THE ONGOING MCS OVR THE ERN
GULF OF MEX.   GFS SEEMS TO BE  EXHIBITING FEEDBACK PROBLEMS HERE
BUT THIS IS ONE OF THOSE CASES WHERE IT COULD WIND UP BEING
CORRECT FOR THE WRONG REASON.   BOTH THE ETA AND GFS HIT THE
CNTRL AND SRN PORTION OF THE STATE HARD DURING THE SECOND HALF
OF THE PD AND SEE LITTLE REASON TO FIGHT THIS SCENARIO GIVEN THE
SUBTROPICAL LIKE MSTR THAT WILL BE INVOLVED.   WHILE THE GFS IS
LIKELY OVERDONE AMTS...DID UPPED THE ETAS TOTALS BASED ON THE
MSTR AVBLTY.

...CNTRL ROCKIES AND CNTRL PLAINS...

BOTH THE ETA AND GFS SUGGEST THAT THE STG DYNAMIC FORCING
ASOCTD WITH A NRN STREAM TROF DIGGING SWD THRU THE N CNTLR U.S.
WILL BE SUFFICIENT TO OVERCOME WEAK LLVL FORCING TO PRODUCE GNLY
LGT PCPN TOTALS ACROSS THIS AREA.   MUCH OF THIS PCPN COULD FALL
IN
THE FORM OF SNOW THOUGH MARGINAL LLVL TEMPS ARE LIKELY TO INHIBIT
ACCUMULATIONS.

DAY 2...

ERN U.S...

STILL HAVING SOME RATHER SIGNIFICANT MASS FIELD DIFFERENCES WITH
THE UPPER LOW/TROF THAT MOVES THRU EASTWARD THRU THE MID-MS
VLY THIS PERIOD.  THE ETA IS MAINTAINING A STRONGER AND MORE
CLOSED OFF SYSTEM WHILE THE GFS IS WEAKER AND A BIT MORE OPEN. 
HOWEVER... IN SPITE OF BEING WEAKER ALOFT...THE GFS IS QUITE A BIT
STRONGER AT THE SFC COMPARED TO THE ETA... AT LEAST WITH THE
LEAD SFC LOW THAT LIFTS INTO THE OH VLY EARLY IN THE PERIOD.  AS
IN
PREVIOUS RUNS... AN EXAMINATION OF THE VERTICAL MOTION FIELDS
SHOWS PLENTY OF GRID SCALE FEEDBACK ON DAY1 WHICH THEN ENDS UP
OVERDEVELOPING THE SFC LOW THAT LIFTS NORTHWARD INTO THE OH
VLY AT A QUICKER PACE THAN THE ETA. DUE TO THE FACT THAT THE GFS
IS HAVING THIS GRID SCALE FEEDBACK PROBLEM AND BECAUSE BOTH THE
UKMET AND CANADIAN ARE SUPPORTING THE SLOWER ETA SOLN... WE
PREFER THE ETA MASS FIELDS OVER THE GFS.

LWR OH RIVER VALLEY....

EXPECTING ONE MAX HERE AS THE ETA PRODUCES A FAIRLY DECENT
TROF AT THE SFC HERE WHERE SOME OF THE MOISTURE WRAPPING BACK
INTO THE WRN SIDE OF THE SYSTEM WILL FOCUS.

MID-ATLC COASTAL AREAS AND SRN NEW ENGLAND....

BY FAR THE HEAVIEST RAIN IS EXPECTED HERE SUPPORTED BY THE
PERSISTENT SLY INFLOW OF MOISTURE FEEDS INTO THE COASTAL TROF
OVER THE AREA OUT AHEAD OF THE MAIN SYSTEM.  WITH PRECIPITABLE
WATER VALUES ABOVE AN INCH AND A 30 TO 40 KT LOW LEVEL JET...
THERE COULD EASILY BE AMOUNTS IN THE 1 TO 2 INCH RANGE FOR THE 24
HR PERIOD.

SRN FLORIDA...

A SLOW MOVING COLD FRONT PUSHING THRU THE SRN HALF OF THE
STATE WILL ACT AS A FOCUS FOR THE ABUNDANT DEEP LAYERED
TROPICAL MOISTURE STREAMING INTO THE REGION FROM THE SRN
CARIBBEAN.  THIS IS THE ONE AREA WHERE THE ETA AND GFS ARE IN
RELATIVELY GOOD AGREEMENT THOUGH THE GFS WAS A BIT WETTER. 

KORTY/ROBSON

GRAPHICS AVAILABLE ON THE WEB AT WWW.HPC.NCEP.NOAA.GOV
 
24HR QP VT 13/00Z
 0.01 518273 520267 520261 516253 511246 508238 504230 501223 
      497213 496210 492207 489201 486206 473212 470214 470216 
      474218 478217 486219 490221 496240 501247 504253 508262 
      513269 516273 518273 
 0.01 449653 447645 443643 439645 434649 429651 424652 412662 
      406667 401673 395682 391690 385700 380705 376708 374710 
      363732 359739 353744 348748 336754 329759 313771 304775 
      298777 292778 274778 269780 266783 260789 249803 244811 
      241819 239829 241838 252855 260855 270852 276850 281850 
      283853 284858 281868 281876 283884 281890 280900 281909 
      280915 281921 284928 286932 286942 286950 287956 289960 
      292961 300959 304964 307968 310968 314970 318979 320981 
      323982 326982 331981 336978 339975 343970 347961 354942 
      357935 362927 368918 376911 382903 387893 395872 398864 
      402855 405849 408845 413834 417824 419815 424791 425778 
      425766 424740 423714 424709 427703 435693 440684 445673 
      447668 449662 449653 
 0.01 508283 508278 506272 504264 502260 499256 497250 495245 
      490241 487239 484241 481239 479235 476233 473234 472240 
      474246 479253 483258 487261 494272 499279 504284 508283 
 0.01 427957 425953 419952 412954 408957 405957 402957 398959 
      395962 383961 377962 372964 367968 363971 355979 349989 
      344996 340000 335003 326009 318016 316020 316027 321032 
      324035 328037 336037 346033 352033 357033 363034 368033 
      374031 375036 370038 366042 363046 360048 350055 346058 
      347063 353064 358068 367072 375080 377081 381080 385078 
      392084 395085 397083 401080 407079 411081 418083 421087 
      423093 426095 430093 430089 427084 427080 429071 431069 
      431065 429059 424045 423032 422022 419016 414002 413998 
      414992 417987 424972 426962 427957 
 0.01 325095 323089 319083 316078 313072 312052 311042 309036 
      301025 298021 297016 295011 291999 292993 292986 292978 
      288974 283975 278980 272992 266002 264008 263017 266032 
      271047 277058 283068 291079 299088 304093 310098 313100 
      319100 324097 325095 
 0.25 428675 426670 422672 416675 410678 406682 400688 392703 
      385712 380718 376725 372733 361749 355756 347761 327770 
      314778 305784 295788 279791 265796 259802 256807 252815 
      251822 250830 251835 253840 258844 266844 274840 281839 
      285840 288842 290845 292851 292859 294868 295875 295879 
      293887 289894 290902 294910 296913 297918 299929 302938 
      305940 309942 316944 319946 321949 325955 329957 334954 
      340949 344943 347936 355921 364908 372892 380877 388863 
      396849 400839 402831 405813 410794 413777 413767 413759 
      411753 410743 409732 409723 410714 413704 418692 426681 
      428675 
 0.25 399061 399057 398057 396057 395058 394061 392063 391064 
      392066 395066 397064 398062 399061 
 0.25 289050 289043 289037 287032 286028 284024 281021 279020 
      277022 275025 275032 275038 277042 280047 282050 285051 
      289050 
 0.50 405714 404707 401705 399706 392714 386722 378730 371744 
      364753 357759 291794 274796 269798 261804 257811 255817 
      254826 255831 258837 263839 272837 283834 286833 290835 
      293837 295842 297852 299859 302866 304868 306866 317855 
      323847 329841 332840 335842 342847 343850 345856 342865 
      339872 335879 333882 331886 332889 330897 326905 321910 
      318913 313916 310914 307909 302904 300904 298908 301914 
      303917 307919 311918 315922 317927 322936 326942 329944 
      332945 339940 342935 351918 361903 365895 369888 386856 
      391847 394839 397829 399820 401810 402801 407780 408771 
      407758 405748 404736 404723 405714 
 1.00 396761 394756 391755 383753 379752 376752 369757 361764 
      354769 346772 336777 329781 321788 311802 295801 287803 
      282802 279800 272802 267804 264807 262811 260814 259821 
      260826 262830 265832 270833 274831 280828 289823 290821 
      294818 301814 308818 311819 314816 317813 322812 329814 
      334818 342822 351821 358819 374812 380807 386798 391791 
      394782 396770 396761 
 1.00 384842 383835 382831 379830 376830 374832 372838 368846 
      364853 359862 354871 352879 351884 347888 338904 333912 
      330920 335926 339925 343921 352905 356898 360889 369873 
      379855 383848 384842 
 1.50 385775 383770 378766 374765 367769 357775 344782 331788 
      329794 329798 332801 338809 342814 348814 354811 358807 
      364803 371800 376795 380790 382785 384779 385775 
 1.50 282809 278808 275808 272806 269808 265812 264816 264819 
      265825 267829 273828 277824 279822 282819 282812 282809 
 2.00 375780 373777 367779 362781 357784 353787 350790 346794 
      346798 347802 353802 356802 361799 364797 368792 371789 
      374785 375780 
 2.00 277814 274814 272815 270817 270818 268821 268823 268824 
      269824 271824 273822 274822 276819 278817 278816 277814  
 
24HR QP VT 14/00Z
 0.01 517689 514685 510678 506674 501671 493665 483662 473660 
      460665 457666 455664 450658 446654 442653 437652 434646 
      431643 428643 423644 413668 406679 401691 392716 389726 
      386730 383731 376734 366738 355739 343742 331747 317752 
      307755 285763 281766 277770 270777 255793 241810 236818 
      230826 226834 224843 233873 236877 239878 244879 250878 
      273870 286866 298864 303865 304868 302873 298879 292885 
      286892 283898 282903 281907 283911 287911 291909 302903 
      307899 312897 315894 323891 326891 327897 325902 325908 
      326916 329922 332926 339925 346923 353919 359916 363912 
      369909 376907 386900 399883 411862 415857 418852 422841 
      427826 430821 436815 439811 441806 447795 468776 471772 
      473766 477760 479754 482745 485741 490738 496734 504730 
      508726 511721 515712 517704 517699 517689 
 0.01 539207 539200 539187 539176 537167 521143 513130 509125 
      505124 502127 498131 492135 478126 472128 470136 472141 
      474141 477141 484143 486146 487151 485156 483156 479155 
      468148 463150 459152 453157 449163 444168 443178 441183 
      441186 443190 439197 443202 446203 449202 451199 456193 
      459188 464183 469183 473186 480190 488192 490194 484200 
      480204 475206 465211 440214 436218 431221 424222 424224 
      427224 441227 448229 444232 434235 422237 421242 424246 
      428252 432255 436257 448258 462263 467266 474269 490277 
      498280 506283 508281 509276 513272 518274 523263 521257 
      518251 516246 514239 512232 510227 507223 505219 503214 
      501210 503206 506202 508202 512207 515211 517215 521221 
      525225 531228 534227 
 0.01 418056 419051 419045 417043 412041 398042 383044 375044 
      366047 361049 357054 358058 360058 367057 372057 371060 
      369061 368066 370068 372071 373075 374080 377082 381080 
      384077 392067 398061 402061 409064 415065 418056 
 0.25 494693 491686 488683 483679 479677 469679 461680 451683 
      440682 435683 433683 429685 426690 423696 421698 417698 
      413702 408712 405718 403722 401725 395730 384738 371743 
      350749 343751 331755 311763 299769 288776 278782 271787 
      263794 257800 250808 246814 243822 240831 240836 243841 
      247844 250843 258839 266834 272831 278829 281831 283836 
      286839 291839 302834 307832 313828 315825 317821 319819 
      322818 331819 338824 342826 347827 351829 353832 357835 
      357839 349836 347849 333861 329865 326869 329871 335870 
      347863 351861 355862 359865 362869 362872 360877 354883 
      349891 347898 348902 351905 356904 379894 387887 394879 
      400871 406863 412853 414849 415843 415836 415828 417821 
      420817 426808 431796 436789 442779 448768 453758 455755 
      459757 464758 467755 468752 472740 476732 480726 489712 
      492706 493703 494693 
 0.25 528208 528203 528202 526198 525197 522196 521197 520201 
      522203 524207 527208 528208 
 0.25 518196 519186 518181 515176 513172 510170 507167 502166 
      497167 493170 489170 489176 492174 497176 500181 503183 
      509187 512189 516195 518196 
 0.25 492262 492256 491252 488247 483245 479239 477237 473234 
      466235 461237 452238 448241 449243 453244 460243 468248 
      474251 482255 487260 492262 
 0.25 403826 404822 401821 399823 398824 397827 396829 398830 
      400831 401832 402830 403827 403826 
 0.50 486700 482693 478690 475689 467691 461695 456699 454700 
      451698 444697 438698 434701 432704 427707 419711 411718 
      407724 402729 394735 384741 376744 362748 348752 338755 
      330758 314766 299774 285781 271790 264796 259802 252811 
      249817 247824 247829 248831 251831 254833 258832 264829 
      271824 284817 292812 297809 305803 309801 314799 322799 
      328803 333807 338809 345810 350807 356805 360805 363807 
      370810 374810 379808 384803 385798 381795 375791 373786 
      374781 376778 381776 384777 388779 391785 393791 399792 
      406796 411803 416804 421799 426792 438777 443771 445767 
      447762 450754 453747 457744 461747 464747 466743 469723 
      470716 473717 477716 483707 486700 
 0.50 408852 405846 402844 394841 389842 385840 383835 384830 
      389822 389820 385818 380819 377822 373826 371831 369836 
      370840 371847 368869 364877 358884 354892 353897 356899 
      367895 372893 378890 385884 392877 398870 404861 407856 
      408852 
 0.50 304827 302824 300823 297823 295823 294823 293824 292825 
      292828 293830 294831 297831 300831 302829 304827 
 1.