Quantitative Precipitation Forecast
Issued by NWS

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793
FXUS04 KWBC 060619
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
119 AM EST SAT FEB 06 2016


PRELIM DAY 1 QPF DISCUSSION
VALID FEB 06/1200 UTC THRU FEB 07/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


...SOUTHEAST STATES...

AN IMPRESSIVE MID WINTER SHORTWAVE DIGS TO A LOW LATITUDE...WITH
500 MB HEIGHT ANOMALIES DOWN TO -2.5 STANDARD DEVIATIONS OVER
FLORIDA BY SUNDAY MORNING. CYCLOGENESIS OFFSHORE OF
FL/GA/SC...ALONG WITH AN INCREASINGLY DEEP UPPER SYSTEM WILL LEAD
TO STRONG ASCENT AND AN INFLUX OF MOISTURE...PRODUCING AN
ORGANIZED PRECIPITATION EVENT ACROSS THIS AREA. MODEL AGREEMENT IS
FAIRLY GOOD THROUGH EARLY DAY 2...AND THE QPF INHERITED FROM THE
PREVIOUS SHIFT PROVIDED A GOOD STARTING POINT. WE INCORPORATED
WHAT LITTLE TREND WAS OBSERVED TO THE QPF CONSENSUS ON THE 18-00Z
CYCLES...MAINLY A WESTWARD EXPANSION OF EACH ISOHYET BY ABOUT 30
MILES...CATCHING MORE OF SE GA WITH 0.10 TO 0.50 INCH AREAL
AVERAGE FOR THE 24-HOUR PERIOD. THE 00Z NAM DID APPEAR TO BE TOO
STRONG WITH THE SYSTEM AT AN EARLIER LEAD TIME...WHICH CAUSED ITS
DAY ONE OUTPUT TO PRODUCE MUCH MORE PRECIPITATION OVER SE GA INTO
COASTAL SC. WHILE THIS REGION SHOULD SEE THE MAXIMUM PRECIPITATION
AMOUNTS...GIVEN THEIR PLACEMENT IN THE DIFLUENT REGION NORTHEAST
OF THE UPPER LOW...THE MANUAL FORECAST IS MORE CONSERVATIVE THAN
THE NAM...BEING MORE IN LINE WITH THE GLOBAL CONSENSUS...THE
CANADIAN GEM REGIONAL MODEL...AND THE NAM CONUS NEST.

MEANWHILE...DOWN ACROSS SOUTH FLORIDA A REMNANT FRONTAL SYSTEM
WILL LIFT NORTHWARD FROM CUBA...BUT IS LIKELY TO REMAIN JUST
OUTSIDE OF THE STATE BEFORE LOW PRESSURE FORMS OFF THE SOUTHEAST
FL COAST AND LIFTS UP TOWARD THE CAROLINAS. AT THE SAME
TIME...HOWEVER...A SHARPLY DEFINED SURFACE TROUGH SHOULD FORM FROM
WEST OF NAPLES...CUTTING ACROSS SOUTH FLORIDA IN RESPONSE TO THE
INTENSE UPSTREAM HEIGHT FALLS. STEEPENING OF LAPSE RATES AND
STRONG SURFACE CONVERGENCE SHOULD BE SUFFICIENT TO FORM
THUNDERSTORMS DESPITE THE AREA BEING NORTH OF THE SYNOPTIC FRONT.
SOME SOLUTIONS SEEMED OVERDONE FOR MAGNITUDES GIVEN THE EVENT WILL
BE QUICKLY EVOLVING...BUT THERE WAS GOOD SPATIAL AGREEMENT TO THE
QPF FROM THE 12Z ECMWF...12Z WRF-NMM...AND 00Z NAM CONUS NEST.
THESE WERE BLENDED WITH THE PREVIOUS WPC FORECAST TO MAINTAIN
CONTINUITY.


...NORTHERN U.S. FROM MONTANA TO NORTHERN  NEW ENGLAND...

A SHARPLY DEFINED NORTHERN STREAM WAVE WILL DEEPEN AS IT ENTERS
THE NORTHERN PLAINS...WHERE HIGH WIND AND BLIZZARD WATCHES WERE IN
EFFECT. A DOWNSTREAM TROUGH WILL ALSO GRAZE THE GREAT LAKES AND
NORTHERN NEW ENGLAND. BOTH WEATHER SYSTEMS ARE WORKING WITH
RELATIVELY DRY AIR...BUT THERE IS AGREEABLE MODEL SIGNAL FOR AREAL
AVERAGE 0.10 INCH LIQUID FROM NORTHERN ND ACROSS NORTHERN MI TO
NORTHERN NY AND MAINE. THE SYSTEM ENTERING NORTH DAKOTA IS
PARTICULARLY DYNAMIC...SUCH THAT IT MAY SQUEEZE OUT AMOUNTS
GREATER THAN A QUARTER INCH THROUGH SUNDAY MORNING UP AROUND
BOTTINEAU AND NORTH OF DEVILS LAKE. THE PREVIOUS WPC FORECAST
PROVIDED A GOOD STARTING POINT...AND WE INCORPORATED SOME ASPECTS
OF THE GFS/ECMWF AND 18Z GEFS MEAN TO DEFINE THE SOUTHERN EXTENT
OF MEASURABLE PRECIPITATION AND EACH CATEGORY UP TO 0.25 INCH
AREAL AVERAGE. THE 00Z GEM REGIONAL AND SOME OF OUR IN-HOUSE
DOWNSCALED QPF TECHNIQUES WERE ALSO HELPFUL...AND LINED UP SUCH AS
TO INCREASE OUR CONFIDENCE.


...NORTHWEST / NORTHERN ROCKIES...

THE SHARP WAVE PASSING TOWARD THE NORTHERN PLAINS WILL PUSH A COLD
FRONT THROUGH THE NORTHWEST STATES AND NORTHERN ROCKIES. MOISTURE
IS IN LIMITED SUPPLY...BUT STRONG WESTERLY TO NORTHWESTERLY FLOW
WILL PAINT THE HIGHER TERRAIN WITH LIGHT ACCUMULATING
PRECIPITATION. MODEL FORECASTS AND OBSERVED PRECIP ASSOCIATED WITH
ANALOG EVENTS FROM THE GEFS REFORECAST DATABASE ARE WELL ALIGNED.
WE STARTED WITH THE PREVIOUS FORECAST AND MADE MINIMAL
CHANGES...INCORPORATING THE GEM REGIONAL AND NDFD FOR SOME OF THE
DETAILS.


...SOUTHERN PLAINS TOWARD THE WESTERN TO CENTRAL GULF COAST...

A STRONG MID LEVEL TROUGH CONTINUED TO DEEPEN AND DEVELOP TOWARD
HAVING A CLOSED CIRCULATION PER SATELLITE IMAGERY. THE SYSTEM WAS
SURROUNDED BY SUCH DRY AIR...HOWEVER...THAT WIDESPREAD RADAR
ECHOES APPARENTLY REPRESENTED MAINLY VIRGA...ALTHOUGH A FEW SITES
IN OK/TX HAD REGISTERED MEASURABLE PRECIPITATION AS OF 06Z. MODELS
CONTINUE TO AGREE THAT THE BEST LIKELIHOOD FOR ANY SIGNIFICANT
RAINFALL WOULD BE JUST EAST AND NORTHEAST OF THE TRACK OF THE MID
LEVEL LOW...ACROSS EASTERN TX. A SECOND SWATH OF PRECIPITATION
WILL FORM OFFSHORE IN THE GULF...WHILE MOST AREAS INLAND ACROSS
SOUTHEAST AND CENTRAL TEXAS SHOULD SEE ONLY A FEW HUNDREDTHS OF AN
INCH AS THE TROUGH PASSES QUICKLY THROUGH THE REGION EARLY TODAY.

BURKE

GRAPHICS AVAILABLE ON THE WEB AT WWW.WPC.NCEP.NOAA.GOV

24HR QP VT 07/12Z
 0.01 532203 533193 532185 528172 525165 521160 514152 505145
      494138 486129 482125 477124 474122 476115 476111 475108
      470105 468103 466105 464111 464101 462094 460089 458084
      450073 446068 442067 436068 432073 436078 442080 446083
      450088 455093 458099 456102 455099 452095 447094 440095
      434094 430089 428106 429116 432118 436114 441117 445121
      446124 449124 452119 456116 461114 463113 463118 462121
      463124 455132 458132 458137 456146 455154 460157 464161
      470165 481163 490172 493176 496183 501188 505191 514198
      524206 529206 532203
 0.01 545987 539957 534944 530937 527929 518899 506872 495847
      489835 489830 490825 493816 497800 498793 499783 498775
      495768 496761 498755 499748 500744 500739 498732 494727
      493720 495712 496706 497701 497696 498691 501690 505686
      509681 511674 510666 507656 501640 494629 492625 490623
      489626 481637 477643 475649 465672 462681 458687 452698
      448712 448719 446725 440740 437746 435753 434769 430785
      426791 425796 424801 427798 433787 441777 445773 448767
      450760 451756 454754 449784 440813 448821 451826 451831
      450834 450839 448843 444848 440851 437858 436863 438866
      442866 444864 447864 447867 445872 444876 444882 445890
      450906 455918 462927 466931 467932 465935 457946 455963
      458968 462974 465979 467983 467987 468996 468006 471021
      475034 483064 485068 485074 486083 489097 491103 493112
      496117 501118 508110 512103 514097 515059 515053 516047
      519042 523039 527033 533022 540011 545987
 0.01 516262 518249 517243 514238 505221 501212 496205 492203
      487201 483203 481206 474209 465211 463213 458214 454218
      459226 467223 474221 484223 489225 492228 496237 498242
      495245 489239 485238 482241 478231 473234 472237 475242
      480248 485256 486261 484266 481269 477271 464278 460287
      457302 458307 461310 464312 469315 473316 477314 484311
      490307 497302 503296 507288 510282 512274 516262
 0.01 482095 482092 483090 481090 479092 481095 480097 482097
      482095
 0.01 452168 452166 450163 449160 448157 446155 445152 443149
      441149 439151 438153 437156 441157 442159 444162 445165
      448165 450168 452168
 0.01 429248 428241 423238 417237 412239 408241 405246 404252
      407256 413256 417254 422251 427249 429248
 0.01 446046 445043 445041 443038 441038 440040 441043 443045
      443046 444046 446046 446046
 0.01 426060 426058 425058 424060 425061 426061 426060
 0.01 415076 415073 413070 412068 414066 415066 416062 414061
      412063 409063 407065 405065 401067 405070 406070 408075
      410075 413076 415076
 0.01 406058 405058 404056 402055 402056 404058 405058 406058
 0.01 357741 356734 353732 345728 340726 335726 331726 327727
      322729 317730 313732 310737 303743 295748 278758 263769
      251782 242797 228833 227837 228841 236837 242843 250839
      257834 260832 267831 285825 287827 293828 303827 306832
      308834 311833 316827 326824 331823 336820 340818 344815
      350809 353799 350787 353776 353764 357741
 0.01 343965 343960 342955 339947 337943 335939 329934 323930
      316926 304918 294906 290899 287890 286886 286880 285869
      282860 278854 274853 270852 267851 263853 258858 255864
      248879 246888 245892 245897 250902 252905 253911 255931
      257939 260947 264966 266968 270970 275968 281969 286968
      289966 294962 299956 303954 308955 323961 334967 343965
 0.25 534000 534994 533987 528979 526976 523970 522966 522962
      523955 522948 518938 514929 512926 509924 508926 509929
      506929 507936 508942 510950 507948 504950 501949 497947
      497952 498957 502967 506975 511983 517990 522996 527005
      529006 532005 534000
 0.25 502278 503273 502270 498268 497276 494280 490284 485287
      481291 482295 485296 491297 495293 498288 501280 502278
 0.25 506006 505001 502994 499988 496982 492979 487981 485987
      485997 487003 491008 495010 501013 505012 506009 506006
 0.25 489142 489139 489138 488136 487135 486134 484136 485137
      486139 487140 488142 489142
 0.25 475845 473844 472843 471843 469843 469846 470847 471846
      473847 475845 475845
 0.25 350744 347743 343744 338745 334745 329744 325746 321745
      318742 316741 313743 308749 304755 297760 284768 272777
      261786 251796 244809 240816 238824 239828 243828 249823
      262816 267812 276809 285806 290807 292809 297813 305814
      314815 321817 328815 334810 339804 341797 343788 343778
      344768 345759 350744
 0.25 324949 323947 321945 319943 317942 316941 314941 313943
      314945 316947 317947 317948 319949 320949 321950 323952
      324949
 0.25 282941 281931 279924 278914 275908 271900 269898 266897
      264900 263905 264913 267921 270929 272935 273940 276942
      280943 282941
 0.50 341757 339755 335755 328759 318770 311774 307774 305771
      311756 313749 311750 308753 304760 299766 288775 282779
      276783 263791 257795 254802 251809 246815 245819 247821
      253816 258813 264807 278801 284797 288797 292799 302810
      317809 324811 328810 331808 336802 338794 339785 339775
      338769 339763 341757
 1.00 332776 332770 329767 322772 316779 311784 304791 301798
      302802 305805 314801 321797 328791 330787 331783 332776
 1.50 327781 326778 324776 319780 316784 313788 310792 307799
      309801 313798 317795 321791 325786 327781
 2.00 315792 315791 315792 315792

$$





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