Quantitative Precipitation Forecast
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS04 KWBC 221755
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
154 PM EDT WED APR 22 2015


PRELIM DAY 1 QPF DISCUSSION
VALID APR 23/0000 UTC THRU APR 24/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

NEW ENGLAND

HEIGHT FALLS ROTATING AROUND THE BASE OF THE STRONG UPPER VORTEX
OVER EASTERN ONTARIO WILL CONTINUE TO PUSH THE ASSOCIATED STRONG
FRONT EAST AND SOUTHEASTWARD OFF THE NEW ENGLAND--MID ATLANTIC
TONIGHT---REMAINING NEARLY STATIONARY WEST OF THIS THROUGH THE
SOUTHEAST AND ALONG THE GULF COAST INTO THE SOUTHERN PLAINS. AN
AREA OF ORGANIZED SHOWERS WILL AFFECT EASTERN NEW ENGLAND
TONIGHT--WITH THE PRECIPITATION AREA SLOWER TO MOVE OUT OF
NORTHERN NEW ENGLAND IN THE VICINITY OF A FORMING COMMA
HEAD/DEFORMATION PRECIPITATION AREA.  HEAVIEST
TOTALS---SUBSEQUENTLY---EXPECTED OVER NORTHERN PORTIONS OF NH INTO
NORTHERN MAINE---WITH LIGHTER TOTALS TO THE SOUTH WHERE THE FRONT
WILL BE MORE PROGRESSIVE.

GREAT LAKES

CYCLONIC FLOW IN THE WAKE OF THIS FRONT---WHICH IS CURRENTLY
PRODUCING WIDESPREAD LATE SEASON SNOW SHOWERS DOWNWIND OF THE
UPPER LAKES---WILL PERSIST THROUGH MOST OF THE DAY 1 PERIOD---ONLY
BEGINNING TO WEAKEN OVER THE UPPER LAKES LATE DAY 1.  MODEL
CONSENSUS IS FOR ONLY LIGHT ADDITIONAL PRECIP/SNOW TOTALS AFTER
0000 UTC.

SOUTHERN PLAINS INTO THE LOWER MS VALLEY---INTO THE EASTERN GULF
COASTAL AREA

THERE CONTINUES TO BE LOW CONFIDENCE WITH QPF DETAILS ALONG AND TO
THE SOUTH OF THE STATIONARY FRONTAL BOUNDARY FORECAST TO REMAIN
ALONG THE GULF COAST INTO THE SOUTHERN PLAINS THIS PERIOD.  THERE
CONTINUES TO BE A LOT OF RUN TO RUN VARIABILITY IN EACH MODEL AND
LARGE MODEL TO MODEL DIFFERENCES.  DAY 1 QPF CONTINUED TO RELY ON
THE HI RES ENSEMBLE MEANS TO MITIGATE THE RUN TO RUN AND MODEL TO
MODEL DIFFERENCES.  SOUTHWESTERLY TO WESTERLY LOW LEVEL FLOW OFF
THE GULF IN THE VICINITY OF THIS FRONT WILL KEEP AN AXIS OF ABOVE
AVERAGE PW VALUES STRETCHING FROM EASTERN PORTIONS OF THE SOUTHERN
PLAINS---ALONG THE GULF COAST AND INTO CENTRAL TO SOUTH FLORIDA.
DAY 1 QPF WAS DRAWN TO DEPICT POTENTIAL FOR CONVECTION FORMING IN
THE INFLOW INTO THE FRONTAL BOUNDARY AND THEN PROGRESSING
DOWNSTREAM IN THIS HIGHER PW AXIS.  MODERATE TO LOCALLY HEAVY
PRECIPITATION TOTALS POSSIBLE HERE--BUT WITH SUCH LARGE MODEL TO
MODEL AND RUN TO RUN DIFFERENCES---CONFIDENCE IN ANY SOLUTION IS
VERY LOW.

SOUTHERN CALIFORNIA--SIERRAS INTO THE WESTERN GREAT BASIN

THE CLOSED LOW OVER SOUTHERN CALIFORNIA NOT EXPECTED TO MOVE MUCH
DURING THE FIRST HALF OF DAY 1 AS ADDITIONAL OFFSHORE HEIGHT FALLS
ROTATE TO ITS SOUTH AND EVENTUALLY TUG THIS CLOSED LOW SOUTHWARD
DURING THE SECOND HALF OF THE PERIOD.  SCATTERED SHOWERS WILL
CONTINUE IN THE VICINITY OF THIS CLOSED LOW FROM SOUTHERN
CALIFORNIA--NORTHWARD INTO THE SIERRA AND THE WESTERN GREAT BASIN
AREA.  GREATEST PRECIP TOTALS EXPECTED AGAIN OVER THE SIERRA WHERE
INSTABILITY WILL BE GREATEST.  MODERATE AREAL AVERAGE PRECIP
TOTALS DEPICTED HERE---WITH LIGHT AREAL AVERAGE AMOUNTS AWAY FROM
THE SIERRA INTO SOUTHERN CALIFORNIA AND THE WESTERN GREAT BASIN.

NORTHWESTERN QUARTER OF THE NATION

TWO AREAS OF HEIGHT FALLS MOVING EASTWARD IN THE NORTHERN STREAM
FLOW FROM THE NORTHEAST PACIFIC INTO SW CANADA/PACIFIC NORTHWEST
WILL AFFECT THE NORTHWESTERN QUARTER OF THE NATION DAY 1.   THE
LEAD AREA OF HEIGHT FALLS WILL BE SLOWING AS IT FEELS THE
INFLUENCE OF THE DOWNSTREAM BLOCKING FLOW OVER CENTRAL TO EASTERN
CANADA.  MODEST PW VALUES EXPECTED ALONG THE ASSOCIATED FRONTAL
BOUNDARY AFFECTING AREAS FROM THE NORTHERN ROCKIES/NORTHERN HIGH
PLAINS---SOUTHWARD INTO THE CENTRAL ROCKIES/CENTRAL HIGH PLAINS.
MODELS ARE FAIRLY SIMILAR IN SHOWING LIGHT TO MODERATE
PRECIPITATION TOTALS ACROSS THESE REGIONS---WITH THE DAY 1 QPF NOT
DEVIATING FROM THIS MODEL CONSENSUS.

THE SECOND AREA OF NORTHERN STREAM HEIGHT FALL EXPECTED TO BE MUCH
STRONGER THAN THE LEAD AREA AS THEY PUSH EAST SOUTHEASTWARD TOWARD
VANCOUVER ISLAND AND THE PACIFIC NORTHWEST THURSDAY AFTERNOON.  AN
ORGANIZED AREAS OF LARGE SCALE LIFT AND ASSOCIATED PRECIP WILL
PUSH INTO THE PACIFIC NORTHWEST EARLY THURSDAY AHEAD OF THESE
HEIGHT FALLS---SUPPORTING LIGHT TO MODERATE PRECIP TOTALS TO THE
WEST OF THE WA/OREGON CASCADES.

ORAVEC

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

24HR QP VT 24/00Z
 0.01 457625 460627 464627 467626 470627 477629 482634 489645
      493652 495655 496660 498663 499668 501679 502689 503695
      505699 510714 513721 515733 512739 510742 506744 503747
      504753 506764 507775 505780 500781 498780 493777 483768
      477765 473764 468765 465765 462764 458764 456762 450760
      446759 440756 437758 435762 434772 435785 433792 430797
      429800 425802 421808 420811 417812 414812 411809 405804
      403800 402797 400797 393801 389806 384809 380809 381800
      386795 392791 399786 401785 402781 404777 405772 407759
      409750 410741 408738 409734 411725 406722 404721 400721
      388729 371732 363733 360731 358727 354721 353717 351714
      350705 351700 354693 357686 361679 367674 384655 393648
      402643
 0.01 515285 521262 521239 520233 517228 512220 507213 502206
      499203 494201 491198 486199 473205 466208 457211 444215
      426220 423222 425225 426228 427231 427235 419237 416242
      415249 418252 422254 427254 431254 440256 445256 451257
      460261 464264 460268 455273 448280 443286 441288 439295
      443302 454303 456302 461303 468302 500299 505300 508299
      513292
 0.01 534090 512068 496066 489063 483059 476061 471065 467067
      465072 463085 459090 455094 442084 438079 439077 442077
      447078 450078 449073 446068 445064 445057 446053 448044
      448039 447035 442031 437027 433025 429025 421026 410026
      404028 396027 388027 382024 380022 377021 374024 373029
      371032 371035 374036 380040 388045 390048 390051 382060
      378067 378071 380074 383076 387075 394071 397069 401070
      405076 405082 403086 402097 379117 375123 373129 381131
      387128 392123 394121 399121 403123 406122 410121 415121
      419123 421126 423129 426128 430123 434116 439122 445129
      448136 452136 455133 460129 463127 466127 473125 480123
      509116 523116 525115 528112 529103 528100 529097 531094
      534090
 0.01 478877 475867 473862 470860 465853 460861 460874 461886
      460891 461898 465905 469903 470900 473895 475890 476885
      477880 478877
 0.01 453855 453848 451845 447843 446846 443851 441851 436849
      432852 432857 436861 438864 443863 447863 450860 453855
      453855
 0.01 413167 416146 417139 417135 413134 403142 399148 396154
      391159 389162 387166 379176 373178 365178 355175 345164
      339165 331163 328164 329168 337172 339173 339177 340186
      341193 344200 348198 352191 355190 359192 366196 375205
      389211 397213 400213 402210 407177 413167
 0.01 368019 369008 367998 366988 366977 367957 367936 351861
      350858 349853 345847 341838 339836 339840 338849 335856
      335860 333863 330872 327878 323883 320883 318878 315869
      310855 306837 304829 301821 297813 292806 283794 280790
      274786 268783 261780 255779 251782 250786 250794 251803
      256820 259838 265856 271869 275875 277884 278893 279902
      282911 285920 289926 291934 294940 295945 294949 292955
      291966 293970 295973 303977 310977 318979 325983 329988
      330992 330996 329999 331002 333007 334010 338013 341017
      346022 348028 350031 354032 361030 368019
 0.01 283993 283988 281986 277987 275988 268990 260990 244989
      237987 234991 230005 230013 236012 238010 243010 249014
      259019 267019 269013 278003 283993
 0.25 512266 513259 513253 510244 502228 500225 496222 494223
      492230 491237 490238 487238 482239 481236 478233 475232
      472234 466239 464242 463245 463248 466251 471253 476258
      485273 491280 499284 503286 507283 509279 508275 507271
      508266 512266
 0.25 498698 498694 496691 494689 489686 485684 483682 481676
      477663 474654 470649 466647 460643 453641 444640 433642
      429644 427647 424651 422655 413659 407661 403665 399672
      400678 402680 406682 412682 415682 410684 401689 395694
      391697 388700 388704 390706 394708 399708 402706 410700
      415693 418688 420682 427678 430678 434679 441684 443688
      442697 441716 472731 479733 484733 488730 494711 497704
      498698
 0.25 480107 480105 481102 480101 479099 477098 475098 474098
      473098 472100 472101 470103 469105 469108 471109 473109
      474109 475109 476108 478108 480107 480107
 0.25 383197 382196 382195 381194 379193 378193 377194 377195
      378196 379198 380199 382198 383197
 0.25 342978 342964 341949 341939 339928 337923 335919 327912
      322907 319903 317898 311877 306858 299837 296826 294817
      291814 287810 281802 277797 273794 268794 264796 264803
      268813 276830 280853 283875 285887 288899 290908 295916
      299924 304933 308941 312949 314958 321966 325973 332979
      339980 342978
 0.50 503278 503270 500264 498258 495253 491249 490244 488243
      484245 482247 482252 485256 489262 491268 494273 498278
      503278
 0.50 483703 481698 478694 476684 472675 467667 463658 458655
      450652 446653 443652 437652 437657 439660 445666 449672
      453683 456692 457699 455704 453706 451711 458716 464719
      467720 472720 476717 479714 482708 483703
 0.50 336967 337955 335942 330924 326918 323913 319911 316904
      313895 308875 302858 296838 294829 291820 285816 280807
      276801 274799 270800 270805 272809 276818 281836 285859
      289877 301907 304916 309924 312931 315941 314943 315949
      320956 328971 333970 336967
 1.00 308892 308890 307889 307888 308886 307885 306884 305883
      304882 303881 302882 303884 303886 304887 304888 305890
      306892 307894 308892
 1.00 298870 298861 296855 296850 294845 293841 291834 290830
      288831 287837 288845 289854 291860 293865 295870 298870

$$





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.