Quantitative Precipitation Forecast
Issued by NWS

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886
FXUS04 KWBC 050733
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
332 AM EDT THU MAY 05 2016


PRELIM DAY 1 QPF DISCUSSION
VALID MAY 05/1200 UTC THRU MAY 06/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1...

...OHIO VALLEY / MID ATLANTIC...

THE 546 DM CLOSED LOW DROPPING TOWARD THE SOUTHERN APPALACHIANS
REPRESENTS LARGE ANOMALIES...4 STANDARD DEVIATIONS BELOW THE
CLIMATOLOGICAL MEAN...BY THE TIME IT DIGS INTO THE SOUTHEAST
STATES. PERSISTENT DIFLUENT FLOW NEAR AND JUST EAST/NORTHEAST OF
THE CLOSED LOW WILL SUPPORT RELATIVELY FOCUSED AND PERSISTENT
RAINFALL FROM THE CENTRAL TO SOUTHERN APPALACHIANS AND IN THE
PIEDMONT OF VA/NC. WITH THE LARGER SCALE WARM CONVEYOR BELT WELL
OFF THE EAST COAST...HOWEVER...THIS SYSTEM WILL WORK WITH VERY
MODEST MOISTURE AND WEAK INSTABILITY...SUCH THAT HEAVY OR EXTREME
RAINFALL IS UNLIKELY.

IN TERMS OF THE 00Z MODEL SUITE...THE GFS REMAINED A WET OUTLIER
WITH ITS 24-HOUR 3-4 INCH MAXIMUM... THIS TIME CENTERED OVER THE
NORTHERN NC COASTAL PLAIN. WPC QPF IN THIS REGION WAS COMPRISED
FROM A BLEND OF THE 00Z ECMWF AND PARALLEL GFS...WHICH NOTED A
MAXIMA BETWEEN 2-2.5"...COINCIDING TO WHERE THE BEST DIURNAL
INSTABILITY IS EXPECTED TO BE LATER THIS AFTN INTO THE EVENING
(MUCAPES 400-800 J/KG).

AS FAR AS THE EXCESSIVE RAINFALL POTENTIAL ON DAY 1...WPC WILL
INCLUDE A MORE CONFINED/NARROW SLIGHT RISK AREA COMPARED TO THE
DAY 2 OUTLOOK FROM YESTERDAY -- STRETCHING FROM PORTIONS OF
EASTERN WV/WESTERN VA SOUTHEAST INTO NORTH-CENTRAL AND NORTHEAST
NC...OR ALONG THE AXIS OF BEST DIFFLUENCE AND DIVERGENCE ALOFT
EAST OF THE UPPER LOW...AND ALONG THE WEAK INSTABILITY AXIS WITH
700-500 MB LAPSE RATES ~7C/KM. PROBABILITIES OF 3 AND 6 HOURLY
QPF>FFG EXCEEDANCE ARE LOW PER THE LATEST SSEO MEAN (30 PCT OR
LESS)...WITH THE LOWER FFG VALUES THE MAIN FACTOR OVER THE
NORTHERN HALF OF THE SLIGHT RISK AREA...WHILE THE HIGHER QPF PER
MODEL CONSENSUS BEING MORE OF A FACTOR OVER NC.


...NEW ENGLAND...

NORTH OF THE CLOSED MID/UPPER LOW...STILL SOME SPREAD IN THE
MODELS WITH THE QPF ACROSS EASTERN NEW ENGLAND ASSOCIATED WITH THE
BACK-BUILDING WARM CONVEYOR BELT (WCB) ON THE BACKSIDE OF THE
INITIAL (OFFSHORE) SURFACE LOW TRACK. THE 00Z ECMWF AND NAM
CONTINUED TO BE WESTERN OUTLIERS WITH THE SURFACE LOW TRACK
(CLOSER TO THE NEW ENGLAND COAST)...AND THUS ARE WETTER ALONG THE
NEW ENGLAND COAST COMPARED TO THE OTHER GUIDANCE. THE GFS REMAINS
FASTEST AND FARTHEST EAST WITH THE LOW...AND (THUS) LIGHTEST WITH
THE QPF. THE PARALLEL GFS...UKMET...AND RGEM ARE A COMPROMISE
BETWEEN THE ECMWF AND GFS...AND GIVEN THE ECMWF TRENDS (CLOSER TO
THE PARALLEL GFS/CMC/UKMET)...HAVE LOWERED THE QPF CONSIDERABLY
FROM 12Z THU-12Z FRI ALONG THE NEW ENGLAND COAST. AREAL-AVERAGE
AMOUNTS ALONG THE COAST RANGE BETWEEN 0.25-0.50"...THOUGH WITH
POTENTIALLY HIGHER AMOUNTS (0.50"+) OVER DOWNEAST MAINE.


...WESTERN U.S...

THE FORMERLY FULL LATITUDE EASTERN PACIFIC UPPER TROF CONTINUES TO
SPLIT INTO TWO PIECES DAY 1. THE PRIMARY CENTER WILL BE THE
SOUTHERN PORTION CLOSING OFF ALONG THE CENTRAL CALIFORNIA
COAST---WHILE THE NORTHERN PORTION REMAINS MORE PROGRESSIVE INTO
CENTRAL CANADA ON FRIDAY. AN AXIS OF ABOVE AVERAGE PW VALUES TO
THE NORTHEAST OF THE CLOSING UPPER LOW WILL REMAIN ACROSS NORTHERN
CALIFORNIA INTO THE PACIFIC NORTHWEST AND (ESPECIALLY) ACROSS THE
NORTHERN INTERMOUNTAIN WEST (WHERE POSITIVE PW ANOMALIES ARE
AROUND 3 STANDARD DEVIATIONS ABOVE NORMAL). BROADLY-DIFLUENT UPPER
FLOW WITHIN THIS HIGH PW AXIS WILL SUPPORT A WIDESPREAD REGION OF
LIGHT TO MODERATE PRECIP TOTALS...WITH ISOLATED HEAVY TOTALS
POSSIBLE. WPC LEANED TOWARD OUR IN-HOUSE ENSEMBLE AND SREF...WHILE
MAINTAINING A GOOD PERCENTAGE OF CONTINUITY...AND ATTEMPTING TO
PRESERVE SOME DETAIL IN THE MOUNTAINOUS TERRAIN.

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

HURLEY

24HR QP VT 06/12Z
 0.01 480616 490627 493631 493640 491649 491661 486677 480692
      474703 464718 459724 455729 450734 444739 442741 439742
      432743 426743 426753 426756 427760 430761 431764 430769
      421796 419806 417816 412831 409839 404844 397845 393845
      391842 389841 387844 381848 375853 373857 369859 360859
      355857 346849 343847 341843 337837 333830 332820 331809
      329806 329801 330787 330785 328783 322785 319784 316782
      314781 313775 314771 314766 319761 322756 330748 351724
      368705 375690 380684 385680 388672 392667 401659 407654
      413648 419643 421640 426639 434638 438634 440631
 0.01 539107 537099 532104 527110 522114 517114 514107 509104
      505108 500112 498110 500106 501102 505079 506072 505067
      501062 497063 491062 488060 485055 481049 475044 473046
      473051 473056 474061 470078 468080 468085 466097 465112
      461121 459122 457121 457116 456114 450111 447106 450112
      447113 445111 445108 446104 447100 449102 455102 454097
      452095 440088 435093 431089 426086 424088 425090 429098
      427100 425101 420100 416098 412092 407086 404082 402077
      401072 399069 396070 394068 396064 396057 394052 393055
      391059 388061 380062 366061 365064 360064 358062 357064
      358069 363070 366072 365074 362076 357080 355082 351081
      336075 330077 329079 330081 336082 339085 343086 346088
      352089 358093 365097 370095 374100 379099 384095 388099
      390103 392106 393110 390111 387111 383108 380109 380115
      381117 385118 390115 395117 397120 399122 402125 411127
      416128 418130 417132 415137 416142 419144 431147 435151
      440155 440162 442166 441170 437173 430167 427165 423165
      418170 412174 409175 405174 400173 395171 390166 383160
      380158 377157 374159 370158 366160 369165 373170 375173
      371176 367173 362174 355177 348181 346184 345180 342172
      336168 320161 310159 303161 299165 301173 311182 314187
      315189 319191 326195 331199 337196 341194 342198 344206
      346210 349211 357217 366222 371223 374222 382226 390238
      398241 404244 411245 418245 420244 425245 428243 430240
      429235 433232 439229 452222 456220 460219 464219 468217
      482216 487216 489214 494210 498205 503200 511193 517187
      522187 525185 530178 533172 531167 529163 529159 529153
      531149 533139 535123 539107
 0.01 478200 479194 479188 474182 472179 468178 463183 458190
      457192 457197 457202 454206 452209 453215 457215 458209
      457207 461205 468206 473203 478200
 0.01 481924 478917 477913 478908 479897 477895 473895 471896
      468895 462894 459892 458886 454881 448882 448878 451877
      453874 457871 461866 447867 442873 440880 434883 433887
      429887 427888 436888 438891 434892 430895 430900 432902
      437902 439904 453906 457906 460904 462906 460909 445910
      436911 433914 438919 444919 460923 466924 468932 469937
      471940 474932 475929 477927 481924
 0.01 389068 387066 385065 384067 382067 382069 383072 385072
      387070 389068
 0.01 349152 347149 345149 343149 341150 341151 341153 343153
      345154 346154 347154 348152 349152
 0.01 267825 267821 264818 259814 257811 253811 251809 249804
      246804 243806 241809 241813 244821 250823 256822 261827
      263829 265828 267825
 0.01 237780 234774 230772 225775 223779 222782 222786 223789
      222793 222799 222803 225805 228805 231798 232792 234786
      235782 237780
 0.25 524166 524160 522155 520150 516146 512139 509137 507138
      504140 500144 496146 494140 491136 485129 482124 478124
      474127 472131 472136 473138 477140 481143 483145 483155
      480155 474151 472155 472160 475161 480160 482160 487164
      488170 493176 494185 496187 504184 511179 518175 521172
      524166 524166
 0.25 478645 475636 471631 468628 464628 456628 451630 445634
      442637 437640 431645 424649 418653 411659 405664 395675
      385687 380693 377700 374708 372717 370725 372729 375730
      382733 386731 388728 396716 399714 404711 412708 428703
      436699 443693 448689 449693 450698 451705 456704 463698
      467692 470686 476667 478657 478645
 0.25 458177 459173 459168 459165 456163 453164 451166 450170
      449173 449176 450180 452181 454181 456179 458177
 0.25 447199 448194 447190 445186 442184 439185 435189 431190
      428188 423188 417189 412193 408195 403196 397194 391190
      381189 375186 368184 362184 361187 362190 369200 376202
      380205 391212 399220 400223 398224 393225 392230 395234
      399237 403237 410238 415236 417231 419226 421225 428227
      434225 437223 439221 441217 439210 438204 439202 444201
      447199
 0.25 418757 417752 413751 407751 399751 391755 384758 376758
      366758 357760 354762 350763 345761 343764 344767 344772
      343777 346786 347795 349801 352804 358806 364810 365814
      363816 357822 353830 351838 352841 355841 360836 365829
      371825 376821 384817 390813 405808 411803 412797 410793
      406786 398788 396789 394783 391780 388779 384779 381777
      385771 391765 394763 399763 403765 406766 409764 411761
      414759 418757
 0.25 377080 376079 375080 375081 377080 377080
 0.50 518161 517153 514149 510146 505147 501152 499159 496164
      499170 500171 504171 507169 511164 516163 518161
 0.50 470646 467639 464635 462633 458632 453631 444639 435648
      413661 397678 389686 381697 379702 377707 377716 379719
      383718 391711 397707 402705 414701 421697 426694 431691
      436689 442686 447681 462663 467654 470646
 0.50 430207 431199 429195 425192 421193 414198 405202 398201
      388195 371189 369191 372194 380200 397211 403218 407221
      410223 409224 406229 403230 396228 396231 414231 411223
      416220 420211 429208 430207
 0.50 401799 398798 396793 393791 392787 390784 386785 382788
      378787 374781 375776 378773 385767 387763 383761 377763
      374763 368762 363763 354766 349768 348774 347780 351790
      354799 363802 377810 376814 380814 384812 387809 393805
      401799
 1.00 450650 449647 447646 445646 443646 443647 442648 441650
      440651 440653 439655 439656 439658 440658 441657 443657
      444656 445656 446655 448653 449652 450650
 1.00 416686 416681 413678 410677 406678 399682 393687 388693
      385699 384703 385706 391702 396698 402692 409689 413688
      416686
 1.00 378796 377792 374790 369784 368781 368776 371769 370767
      365768 361767 356769 353771 352775 353780 354786 359791
      364796 370798 374798 378796
 1.50 366786 365782 365778 365773 363771 360770 357772 355774
      355777 356780 357783 360785 362787 364788 366786
 2.00 362774 362773 360773 359774 359775 357776 357777 359779
      361779 361778 362776 362774 362774

$$





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