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 200653
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
253 AM EDT WED MAY 20 2015


PRELIM DAY 1 QPF DISCUSSION
VALID MAY 20/1200 UTC THRU MAY 21/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

MID TO LOWER MS VALLEY INTO THE SOUTHERN PLAINS

SHORTWAVE ENERGY MOVING EAST NORTHEASTWARD FROM THE SOUTHERN
PLAINS---SUPPORTING THE CURRENT ACTIVE CONVECTION ALONG THE
STATIONARY FRONTAL BOUNDARY OVER THE SOUTHERN PLAINS---WILL BE
PUSHING EAST NORTHEASTWARD INTO THE LOWER TO MID MS VALLEY
WEDNESDAY.  CONFIDENCE IN MODEL QPF SOLUTIONS IS LOW GIVEN RECENT
PERFORMANCE AND THE CONTINUED WIDE SPREAD WITH SOLUTIONS.  WPC
CONTINUES TO FAVOR THE HI RES ARW---NMMB AND CMC GEM WHICH HAVE AN
OVERALL  FARTHER SOUTH AXIS TO THEIR RESPECTIVE QPFS.  THIS IS
ESPECIALLY DURING THE BEGINNING OF DAY 1 PERIOD WHEN THE
CONVECTION WILL LIKELY STILL BE WELL DEFINED.  TRAINING OF CELLS
IN A GENERAL WEST TO EAST DIRECTION MAY CONTINUE INTO THE FIRST
PART OF THE DAY 1 PERIOD IN AN AXIS OF MOIST WEST SOUTHWESTERLY TO
WESTERLY LOW LEVEL FLOW IN THE VICINITY OF THE WEST TO EAST
ORIENTED FRONTAL BOUNDARY FROM SOUTHEAST OK---NORTHEAST TX INTO
CENTRAL TO SOUTHERN AR.    LATER DAY 1---PRECIPITATION MAY FIRE
FARTHER TO THE WEST ALONG AND AHEAD OF THE SOUTHWARD MOVING
PORTION OF THE FRONTAL BOUNDARY ACROSS CENTRAL TO SOUTH-CENTRAL TX
AS MOIST SOUTHERLY TO SOUTHEASTERLY FLOW IS EXPECTED AHEAD OF THIS
FRONT. CONFIDENCE LOW WITH QPF PLACEMENT ALONG THIS PORTION OF THE
FRONT GIVEN THE WIDE SPREAD IN SOLUTIONS.   WEDNESDAY NIGHT INTO
EARLY THURSDAY---SHORTWAVE ENERGY MOVING OUT OF NORTHERN MEXICO ON
THE SOUTHERN EDGE OF THE WESTERLIES MAY IGNITE MORE ORGANIZED
CONVECTION NEAR THE BIG BEND---WITH THIS ACTIVITY THEN PUSHING
SOUTHEASTWARD ALONG THE RIO GRANDE IN THE EARLY HOURS OF THU.
THERE IS SUPPORT FOR THIS SOLUTION IN THE HI RES
ARW--NMMB---ECMWF---NAM CONEST AND CMC GEM---ALTHOUGH THEY DO
DIFFER WITH RESPECT TO HOW FAR TO THE SOUTHEAST CONVECTION
PROPAGATES.  HEAVY TO ISOLATED EXCESSIVE RAINFALL AMOUNTS POSSIBLE
WITH THIS CONVECTION IN THE EARLY HOURS OF THURSDAY.

MID MS VALLEY---OH VALLEY---TN VALLEY INTO THE CENTRAL TO SOUTHERN
APPALACHIANS

MODEL CONSENSUS IS FOR LIGHTER PRECIPITATION TOTALS FROM THE MID
MS VALLEY INTO THE OH VALLEY AND SOUTHWARD INTO THE TN VALLY AND
ACROSS THE CENTRAL TO SOUTHERN APPALACHIANS DAY 1 AS THE HEIGHT
FALLS PUSHING OUT OF THE SOUTHERN PLAINS EARLY DAY 1 ACCELERATE
EASTWARD.  ABOVE AVERAGE PW VALUES WILL PERSIST ALONG AND AHEAD OF
THE COLD FRONT EXPECTED TO PUSH SOUTHEASTWARD INTO THE LOWER MS
VALLEY/TN VALLEY.  THIS MAY SUPPORT LOCALLY HEAVY RAINFALL
AMOUNTS--ALTHOUGH WITH NO CLEAR MODEL SIGNAL FOR
PLACEMENT---AMOUNTS WERE KEPT ON THE MODERATE SIDE IN THE WPC DAY
1 QPF.  OVERRUNNING RAINS TO THE NORTH OF THE ASSOCIATED WEAK
SURFACE WAVE PUSHING EASTWARD WILL BRING LIGHT TO MODERATE PRECIP
AMOUNTS FROM THE MID MS VALLEY INTO THE OH VALLEY AND THE CENTRAL
TO SOUTHERN APPALACHIANS.

NORTHERN CALIFORNIA---OREGON INTO THE NORTHERN GREAT BASIN

A REGION OF ABOVE AVERAGE PW VALUES WILL REMAIN ANCHORED FROM
NORTHERN CALIFORNIA/OREGON INTO THE NORTHERN GREAT BASIN DAY 1 IN
A CONTINUED BLOCKED FLOW PATTERN BETWEEN THE ALBERTA/SASKATCHEWAN
CLOSED HIGH AND THE MEAN TROF OFF THE CALIFORNIA COAST.  SCATTERED
SHOWER ACTIVITY LIKELY AGAIN IN THIS ABOVE AVERAGE PW AXIS THAT
COINCIDES WITH A MAX REGION OF UPPER DIFFLUENCE.  THIS WILL
SUPPORT AREAL AVERAGE MODERATE TO ISOLATED HEAVY PRECIP TOTALS DAY
1 ACROSS THESE AREAS.

ORAVEC

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

24HR QP VT 21/12Z
 0.01 505234 504224 503216 498210 495207 491206 483205 476207
      463213 460214 456214 451208 454199 458190 461187 462183
      463177 463171 458154 456144 455136 455132 455125 457120
      457114 456105 451099 447094 438093 427086 424088 425093
      427096 425101 422103 421107 416108 414104 411098 408096
      406098 404102 394109 390111 390116 395122 403123 411122
      415124 415130 414132 415135 413138 407141 400140 396147
      397150 398153 398156 396160 392160 384161 381165 386173
      388183 386186 383187 377182 372180 367180 362184 366189
      378200 383205 389208 396213 399216 398220 395221 392225
      392229 392233 392238 394241 400247 406251 413250 428250
      437250 444247 448244 449238 448234 450229 453228 456226
      459225 463226 467225 474222 486221 489220 491224 494234
      497238 499241 500240 505234
 0.01 485707 482700 478691 475682 472683 470686 470690 469694
      467702 468714 470717 471721 473726 475727 480722 482713
      485707
 0.01 443041 444033 442029 440021 438014 437005 438000 437996
      436989 435983 432960 428936 428929 426925 426914 422893
      421889 420882 419870 419865 417860 414852 411845 407839
      405836 403830 404827 403824 404816 407808 409798 409792
      410788 406782 402780 400777 395769 392766 388767 386769
      384774 382781 381786 378788 369790 366793 364796 362803
      359808 342840 337844 335846 330847 325848 322851 320854
      320859 318864 316865 315861 313852 313846 314841 321837
      326836 329834 334829 338825 341819 344796 345793 345787
      343781 341778 341773 341766 339760 337758 333756 329757
      325764 311790 305796 296797 289797 281797 274802 271804
      268808 264814 262819 274826 287831 291833 294836 298839
      299845 297850 297856 298868 298878 298883 297888 293901
      291911 291917 290923 290934 288939 288944 288970 291977
      289981 286983 280987 272988 257990 255992 254998 254006
      258012 263015 271019 278024 286028 294031 300035 304040
      308045 316049 323055 326057 331058 335056 340056 350057
      354056 357058 361058 364057 371055 377054 389064 391064
      392068 392073 393081 394085 400082 403079 407077 411076
      413074 414068 414061 411054 405049 399044 392045 388046
      385044 383042 378042 372043 366044 357044 352043 349043
      348040 347034 346028 344018 344005 343000 344995 348974
      350955 353951 356949 363946 371944 380943 388944 394947
      398956 401965 403975 407984 413998 420014 423025 429031
      432040 437047 441047 443041
 0.01 343182 344175 343171 341168 336166 332164 327163 324165
      323167 328169 331171 336174 339177 340181 343182
 0.25 456179 456174 456172 455168 454164 452162 451160 449163
      449168 448172 448177 448180 452182 455181 456179
 0.25 446223 441213 440207 440197 437192 433192 429194 427199
      425200 414202 412205 414211 414219 411224 409227 409231
      414235 419238 423236 433232 442227 446223
 0.25 422167 422165 422164 422162 421159 421157 420155 419154
      418153 417153 416153 416156 416157 417158 417161 417163
      418163 419165 420166 422167 422167
 0.25 412898 411889 409883 400873 388869 381870 378870 377873
      371877 365877 355870 363860 367855 367847 364842 359840
      352841 347847 345853 340856 336861 334869 329880 331901
      331910 332913 330915 326919 323925 320931 319936 316954
      316963 314970 310976 306980 297987 290988 284991 273997
      272004 273007 271009 270012 271014 274017 287023 293026
      298028 305027 309022 312015 313009 316002 320996 324992
      328989 334975 339963 347952 356943 366936 375931 378928
      382929 388931 394932 399930 403924 404915 408905 412898
 0.25 338795 337791 335787 333787 330789 327796 323802 318807
      311811 309813 310816 315817 319817 325819 331815 335809
      337802 338795
 0.25 305816 305814 302813 299812 295810 291809 287808 282808
      280811 282815 285817 288819 292821 296823 301823 301819
      305817 305816
 0.50 385890 385888 382887 378887 374889 371892 365891 358881
      353878 348875 345873 341871 338873 335878 336887 337892
      340898 346900 348901 347903 337926 332938 331946 330954
      330959 330963 332965 336962 339958 355941 363934 368929
      370925 375914 376908 375904 373899 374896 379894 385890
 0.50 309005 310997 308992 306990 302993 297000 291992 280995
      276997 275000 276003 277008 275013 279016 283019 294023
      300021 304019 307014 308009 309005
 1.00 358925 358919 357912 355910 351910 348912 345917 341924
      337932 335943 335949 336956 340954 343951 348943 353936
      357927 358925
 1.00 291012 291010 289010 287009 286010 286012 287014 288014
      289014 291013 291012
 1.50 348923 344923 342925 340930 339934 339939 338943 337947
      338952 341950 343947 343944 344939 345934 346929 348924
      348923

$$





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