QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
513 AM EST FRI JAN 16 2009
 
 
FINAL DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION
VALID JAN 16/1200 UTC THRU JAN 19/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR
 
 
UPDATE...

ONLY SOME MINOR CHANGES MADE TO THE PRELIM DAY 1 QPF FOR THE FINAL
ISSUANCE TO ACCOUNT FOR THE 0000 UTC ECMWF.

DAY 1...

THE LATEST MODELS CONTINUE IN GOOD AGRMNT WITH THE HIGHLY
AMPLIFIED FLOW ACRS THE NATION THIS PERIOD.  MUCH ABOVE NORMAL HTS
WL CONT WITH THE WRN NOAM UPR RIDGE...WHILE  BELOW NORMAL HTS CONT
DOWNSTREAM ACRS ERN NOAM.   SIMILAR TO PREVIOUS RUNS...A MAJORITY
OF THE NATION WL HAVE DRY WEATHER IN THIS HIGHLY AMPLIFIED FLOW.

GTLKS...

THE PERSISTENT CYCLONIC FLOW ACRS THE GTLKS WL SUPPORT ADDITIONAL
LAKE EFFECT SNOW SHOWERS THROUGH MOST OF FRI.  SHRTWV RIDGING
AHEAD OF THE UPSTREAM CLIPPER SYSTEM DIVING SEWD ACRS SCNTRL CAN
WL LEAD TO A DECREASE IN LAKE EFFECT ACTIVITY FRI NIGHT INTO EARLY
SAT FOR THE UPR LAKES AS THE WNWLY LOW LEVEL FLOW BACKS TO A MORE
SWLY AND SLY DIRECTION.

ARROWHEAD OF MN...WRN U.P. OF MI...NRN WI...

MODELS FAIRLY SIMILAR WITH THE ABOVE MENTIONED CLIPPER SYSTEM
DIVING SEWD TOWARD THE NRN PLAINS/UPR MS VALLEY FRI NIGHT INTO
EARLY SAT.  ISENTROPIC LIFT ON THE EAST AND NORTHEAST SIDE OF THIS
SYSTEM WL SUPPORT POTENTIAL FOR LIGHT TO MDT SNOWFALL AMTS FROM
INVOF THE ARROWHEAD OF MN...SEWD INTO NRN WI AND THE WRN U.P. OF
MI.  

LOWER RIO GRANDE...

SIMILAR TO PREV RUNS..THE GFS IS SHOWING MORE WIDESPREAD LIGHT
PCPN SPREADING N OF THE LOWER RIO GRANDE ACRS S TX FROM WEAK
SHRTWVS OVERRUNNING THE LOW LEVEL COLD AIR OVR THE SRN PLAINS.   
THE NAM...ECMWF AND CMC KEEP NEARLY ALL OF THE PCPN TO THE SOUTH
OF THE RIO GRANDE OVR NRN MEXICO.  THE DAY 1 QPF WENT WITH THE
MAJORITY FARTHER SWD PCPN AXIS HERE.

 
 
DAYS 2 AND 3...

THE OVERALL UPPER-LEVEL PATTERN ACROSS THE LWR 48 WILL CHANGE
LITTLE ON SAT AND SUN... AS A LARGE SCALE UPPER RIDGE CONTROLS
EVERYTHING IN THE WEST AND A LARGE SCALE EXTREMELY COLD UPPER
TROUGH REMAINS IN CONTROL EAST OF THE ROCKIES. 

A STRONG SHORT WAVE STARTING OFF OVER THE UPR MS VLY ON SAT WILL
DIG INTO THE GRT LAKES/OH VLY AND FORCE THE COLDEST AREA OF
SURFACE HIGH PRESSURE OF THE WINTER OFF THE ERN SEABOARD.
ACCOMPANYING THIS IMPULSE WILL BE A DECENT AREA OF LOW PRESSURE...
A STRONG COLD FRONT AND ANOTHER COLD SHOT INVADING THE MS VLY/GRT
LAKES AND OH/TN VLYS. THE LACK OF ANY LL MOISTURE TO ACT ON WILL
KEEP QPF AMOUNTS OR SNOWFALL RATHER LIMITED WITH THIS SYSTEM AND
MAINLY CONCENTRATED NEAR THE SURFACE LOW TRACK. HPC FOLLOWED A
BLEND OF THE 00Z ECMWF AND UKMET ON THIS SYSTEM OVER THE GFS/NAM
DUE TO BETTER CONTINUITY AND PERFORMANCE AS OF LATE. THIS WOULD
MEAN A SOLID STRIPE OF A .10 TO .30 OF AN INCH FROM MI INTO NRN
IN/OH AND WRN PA/NY. 

ON SUN... A TRIPLE POINT LOW WILL BEGIN TO SLIDE FROM THE ERN OH
VLY TOWARD THE NORTHEAST COAST... AS THE ENTIRE UPPER TROUGH
LIFTS/GOES A SLIGHT NEGATIVE TILT THROUGH THE NORTHEAST. THE
BACKING OF THE FLOW SHOULD ALLOW THIS INTENSIFYING IMPULSE TO DRAW
IN SOME ATLANTIC MOISTURE AND THIS FETCH STREAM RIGHT INTO ERN NEW
ENGLAND... ESPECIALLY INTO MAINE. EXPECT THE HEAVIEST QPF AMOUNTS
HERE... WHILE ENOUGH MOISTURE STRETCHES BACK TO THE UPPER LOW
BASED OVER SERN ONTARIO. THE ASSOCIATED SURFACE COLD FRONT WILL
SWEEP THROUGH THE SOUTHEAST AND ENOUGH UPPER DYNAMICS DIGGING
THROUGH THE BASE OF THE UPPER TROUGH SHOULD IGNITE A NARROW SWATH
OF PRECIP FROM THE SOUTHEAST COAST BACK TO THE NERN GULF COAST.

MEANWHILE UPSTREAM... YET ANOTHER SOLID SHORT WAVE ARRIVING FROM
CENTRAL CANADA WILL DIG IN UNISON WITH AN ARCTIC UPPER LOW AND
HELP RE-ESTABLISH THE AMPLIFICATION OF THE UPPER TROUGH FROM THE
GRT LAKES BACK INTO THE LWR MS VLY. ALL OF THE ACTION TAKING PLACE
DOWNSTREAM WILL ONCE AGAIN TRANSLATE TO A LACK OF LL MOISTURE TO
INTERACT WITH THIS POTENT FEATURE AND EXPECT ANOTHER LIGHT STREAK
OF SNOW NORTH OF THE SURFACE LOW TRACK OR ACROSS THE UPR MS
VLY/WRN GRT LAKES INTO THE OH VLY.  
           

ORAVEC/MUSHER
 
GRAPHICS AVAILABLE ON THE WEB AT WWW.HPC.NCEP.NOAA.GOV
24HR QP VT 17/12Z
 0.01 545957 545952 545949 543943 538937 529927 520919 510909 
      500896 491884 487880 483873 477861 475855 475849 474838 
      470816 463803 459797 455787 453748 452741 449737 442738 
      438738 432739 430741 428746 428763 427775 426778 423781 
      419786 416796 414799 413803 415814 417818 419820 430822 
      436823 439826 447830 450834 451839 450845 448848 444849 
      430851 423855 419859 419866 421873 424883 427890 430896 
      430902 433907 441917 460938 469949 476957 487967 498974 
      503977 510979 523978 532975 539969 543962 545957 
 0.01 451722 450718 449714 446713 445712 442712 440714 438717 
      438718 437723 436728 439730 440730 442729 445728 448727 
      450725 451722 
 0.01 407954 406948 405945 401940 398936 395933 395930 393923 
      389918 381911 376907 372906 369906 368909 366915 365929 
      372942 375947 379952 386958 392960 398962 404958 407954 
 0.01 267799 267796 265795 263794 262791 261791 257790 255790 
      252791 250792 247794 246798 246799 246801 247804 248805 
      249806 252807 254806 257805 260805 262804 265803 267800 
      267799 
 0.01 230997 234001 240004 248010 257018 263023 268025 274026 
      280025 290021 289014 286007 282003 277999 266993 257988 
      245980 241978 238976 234977 232983 230988 
 0.25 455814 455810 454806 452802 451801 449799 447798 444798 
      441798 440800 439803 439804 440808 441812 442813 443815 
      446818 447818 450819 453819 455815 455814 
 0.25 441764 441760 441756 439752 437749 435748 433751 433756 
      433760 433761 434764 434768 435772 436776 438777 439774 
      440772 441769 441766 441764 
 0.25 262005 261002 258999 255997 250994 247993 244992 238990 
      237993 238996 240998 245000 247001 252003 256005 259007 
      262005  
 
24HR QP VT 18/12Z
 0.01 471697 466697 465693 464682 461674 458668 454666 448666 
      445670 443673 442677 438687 436692 432696 428697 425695 
      420693 416693 407698 402708 399714 397721 396729 396741 
      396753 397756 401762 403766 404770 403776 401780 396783 
      390792 379801 349827 343836 339845 330864 325871 317878 
      313885 309894 306903 301911 291928 282944 282948 286949 
      293945 308932 325920 348891 353882 356874 361865 369855 
      376848 380843 384841 388840 391845 396853 402862 407868 
      416876 420878 426880 433882 437885 439891 444901 452907 
      461911 468914 476914 482909 485904 487899 489893 489887 
      488878 486871 484862 481856 477844 465821 463811 460801 
      460797 460787 461777 462770 461764 461757 461751 465745 
      465740 463732 463725 464713 471697 
 0.01 282799 280795 276792 272790 269789 266788 261788 257789 
      257793 255797 255800 257803 262804 265804 271803 274803 
      279802 282799 
 0.01 287000 288997 285993 282992 279989 279985 278979 274974 
      272973 271977 272983 266990 257993 252997 254000 258002 
      266003 271001 274998 280004 284003 287000 
 0.25 454866 455860 454853 451842 448830 445819 441812 439806 
      439800 432798 426795 423793 418794 412793 410798 411806 
      419823 424829 426840 429848 434856 435859 436865 439868 
      442865 445865 448869 453869 454866 
 
 
24HR QP VT 19/12Z
 0.01 483677 479669 472662 460653 453649 449648 446649 429659 
      413665 407668 400673 392678 386685 382692 380702 379709 
      381714 383716 394721 399733 402744 402749 401753 395761 
      389766 384774 378786 377790 378794 376799 374801 366807 
      361810 355809 359802 362794 362786 362777 365768 373753 
      381739 383736 385731 385728 383724 377720 372719 364721 
      354726 341738 329751 318764 310777 303789 297803 290815 
      283825 279840 277853 277860 279865 284870 283885 284900 
      286911 289913 293912 295915 295919 293926 292929 294933 
      300935 305934 308932 312927 319915 326899 333884 337872 
      340863 343857 347850 351846 356843 361842 368844 382846 
      385848 386853 380858 378859 376866 379872 381875 393887 
      398892 401895 406895 411890 415891 422893 428896 435899 
      442901 449906 454913 460919 469917 485920 490918 494914 
      500907 504899 507891 505887 502884 497881 494878 492872 
      487865 480860 476858 471857 469855 469844 466840 462843 
      458852 455858 450860 447860 431854 419848 413844 413839 
      417836 421842 424845 427846 443842 452838 455836 456831 
      455819 453808 451796 451786 452781 454779 459776 464768 
      466763 467757 464746 461738 460734 462730 478701 482687 
      483677 
 0.01 267977 266971 266967 263963 262960 256960 254962 250965 
      248968 247971 248976 250980 253982 255985 258988 263989 
      265986 266980 267977 
 0.25 474680 470672 464668 458663 452661 445661 439663 431668 
      427672 425676 422684 417691 413696 409699 407704 413713 
      418717 424718 431718 438717 443714 448709 455705 462701 
      467696 473688 475684 474680 
 0.25 439779 440774 438770 436770 435772 434774 435777 435778 
      439779 439779 
 0.25 360746 358744 355745 349751 342759 335767 329775 325785 
      324790 322795 318804 312813 308821 307832 306844 307846 
      310848 313847 317842 319838 324829 328819 331809 337788 
      347772 358751 360746 
 0.50 458674 454667 451665 447665 441668 433673 430677 430680 
      426688 425695 427698 430698 439694 444691 452688 456685 
      459677 458674