Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 220700
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
259 AM EDT WED MAY 22 2013


PRELIM DAY 1 QPF DISCUSSION
VALID MAY 22/1200 UTC THRU MAY 23/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1


...PACIFIC NORTHWEST INTO THE NORTHERN GREAT BASIN AND NORTHERN
ROCKIES...

AN ANOMALOUSLY DEEP LATE SPRING UPPER LEVEL LOW (2 STD DEVIATIONS
BELOW THE NORM AT 500 MB PER THE SREF/GEFS) WILL SLOWLY PINWHEEL
ITS WAY INTO THE NRN GREAT BASIN TOWARD THE END OF DAY ONE (WED
NIGHT). THE CLOSED NATURE OF THIS SYSTEM WILL BRING ONLY MODEST
ONSHORE FLOW/MOISTURE ADVECTION TO THE REGION...HOWEVER THE MOIST
ONSHORE FLOW...STEEPENING MID LEVEL LAPSE RATES... AND STRONG
OROGRAPHIC CONTRIBUTION WILL NEVERTHELESS MAKE FOR WHAT SHOULD ADD
UP TO BE A MODERATE PCPN EVENT TODAY AND TONIGHT ACROSS THE WA/OR
COASTAL RANGES (INCLUDING THE OLYMPICS) AND INTO THE CASCADE
RANGES.  SOME OF THE PCPN WILL FALL IN THE FORM OF SNOW ACROSS THE
HIGHER ELEVATIONS OF THE CASCADES...AS SIGNIFICANTLY LOWER HEIGHTS
ALLOW WET BULB ZERO LEVELS TO FALL BETWEEN 3500-4500 FT PER THE
NAM/GFS.

FARTHER EAST ACROSS THE NRN ROCKIES...MOIST S-SE INFLOW (30-35 KT
AT 850 MB) ALONG WITH THE DPVA AND DEEP LAYER QS FORCING EAST OF
THE CLOSED LOW WILL LEAD TO AN ANOMALOUS (WHILE RELATIVELY NARROW)
REGION OF LLVL MSTR FLUX WITH PW`S AROUND 0.75".  EXPECT MOD TO
HVY PCPN AMOUNTS ACROSS NRN ID AND WRN MT DURING DAY ONE AS A
RESULT...ESPECIALLY OVER THE SOUTHERN-FACING SLOPES WHERE SOME
OROGRAPHIC ENHANCEMENT IS EXPECTED.  GIVEN THE STRONGER DYNAMICS E
OF THE NRN GREAT BASIN...THIS IS ONE OF THOSE SETUPS (GIVEN A MORE
SOUTHERLY VS. WESTERLY FLOW) WHERE PCPN AMOUNTS OVER THE NRN
ROCKIES ARE EXPECTED TO BE ON PAR IF NOT HIGHER THAN ACROSS THE
CSTL RANGES AND CASCADES.


...LOWER MS VALLEY NORTHEASTWARD INTO THE OH VALLEY AND GREAT
LAKES...

THE SRN...MESOSCALE-ENHANCED VORTICITY CENTER AT THE TROUGH BASE
OVER THE SRN PLAINS/LWR MS VLY WILL LIFT NE AND EVENTUALLY BECOME
ABSORBED WITHIN THE TROUGH ACROSS THE MID MS VLY BY WED EVENING.
MEANWHILE...THE TROUGH WILL FINALLY BECOME A BIT MORE PROGRESSIVE
W-E TONIGHT THANKS TO AN ELONGATED NRN STREAM SHORTWAVE PIVOTING
ACROSS THE LOWER HUDSON AND ST. JAMES BAY.  THE 00Z MODELS
CONTINUE TO LINE UP FAIRLY WELL IN TERMS OF THE MASS
FIELDS...HOWEVER THE QPF OVER THIS REGION IS STILL NOT QUITE AS
PROGRESSIVE IN THE NEAR TERM (0-12 HRS) AS IT SHOULD BE PER
EXTRAPOLATING THE MULTICELLULAR LINEAR CONVECTION EARLY THIS AM.
AS WAS NOTED IN THE PRIOR DISCUSSION...THERE IS A GENERAL MODEL
AGREEMENT ON A DECREASE IN HEAVY RAINFALL POTENTIAL TODAY AS THE
UPPER DYNAMICS WEAKEN.  AT THE SAME TIME HOWEVER...ABOVE NORMAL
PW`S (1.5 TO 1.75"...HIGHEST SOUTH TOWARD THE GOMEX) FROM THE
LOWER MS VALLEY NORTHEASTWARD THROUGH THE OH VALLEY/INTO THE LOWER
GREAT LAKES) ALONG WITH THE BROAD-SCALE (ALBEIT WEAKENING)
VERTICAL ASCENT AND MODEST LLVL MSTR POOLING (ENHANCED BY
OUTFLOWS) WILL GENERATE MODERATE 24 HR TOTALS ACROSS THIS REGION.
THE HIGHEST AREAL-AVERAGES...UP TO 1-1.5 INCHES...ARE EXPECTED
OVER PTNS OF THE UPPER MIDWEST (ERN WI THROUGH MUCH OF LOWER MI)
GIVEN THE FVRBL THERMODYNAMIC PROFILE (K INDICES INTO THE LOW-MID
30S) ALONG WITH ENHANCED UPPER LEVEL DIVERGENCE (AND LOW-MID LEVEL
FGEN) WITHIN THE RRQ OR RIGHT ENTRANCE REGION OF THE JET STREAK
SOUTH OF ST. JAMES BAY.

...UPPER MS VALLEY...

THERE REMAINS GOOD MODEL AGREEMENT ON A SLOW EASTWARD MOVEMENT TO
THE WELL DEFINED CLOSED LOW MOVING INTO THE UPPER MS VALLEY REGION
DAY 1.  ADDITIONAL LONG DURATION LIGHT PRECIPITATION AMOUNTS
LIKELY IN THE COMMA HEAD/DEFORMATION PRECIPITATION BAND ASSOCIATED
WITH THIS UPPER CENTER.


...NORTHERN NY INTO NORTHERN NEW ENGLAND

TO THE EAST OF THE MID-UPPER MS VALLEY CLOSED LOW...WSW TO SW
LOW-LEVEL FLOW WILL CONTINUE TO OVERRUN THE WEST TO EAST ORIENTED
WARM FRONTAL BOUNDARY MOVING SLOWLY NORTHWARD THROUGH THE UPPER
LAKES...NORTHERN NY...AND NORTHERN NEW ENGLAND.  THIS WILL
CONTINUE TO SUPPORT MODERATE TO HEAVY CONVECTIVELY-AIDED RAINFALL
POTENTIAL AMOUNTS IN THE OVERRUNNING ZONE TO THE NORTH OF THIS
BOUNDARY.  THE PREVIOUS GLOBAL AND EVEN NEAR-TERM HIGH RES MODELS
SUCH AS THE RUC/HRRR DID NOT HAVE A GOOD HANDLE ON THE WDSRPD AREA
OF CONVECTION MOVING ACROSS ERN NY AND NEW ENGLAND DURING THE
PRE-DAWN HRS WED...AND AS SUCH WPC OPTED TO USE CONTINUITY RADAR
EXTRAPOLATION THROUGH 12Z WITH THE QPF...THEN USING A MULTI-MODEL
ENSEMBLE (BOTH GLOBAL AND HIGH-RES RUNS) THEREAFTER.

...FLORIDA...

THE CLOSED LOW OVER NORTH FL IS EXPECTED TO MIGRATE SLOWLY NE-WRD
AND EVENTUALLY OFF THE NE COAST OF FL LATER TODAY. CONTINUED S-SE
LOW LEVEL FLOW TO THE SOUTH AND SOUTHEAST OF THIS UPPER CENTER IN
THE AXIS OF ABOVE AVERAGE PW VALUES STREAMING OFF THE ATLANTIC
WILL MAY FOCUS ISOLATED VERY HEAVY RAINFALL AMOUNTS ALONG THE
COASTAL SOUTHEAST PORTIONS OF FL.  THESE HEAVY TOTALS MORE LIKELY
IN THE MORNING HOURS NEAR THE E COAST...WITH CONVECTION THEN
PROGRESSING INLAND DURING THE AFTERNOON AS THE LLVL MOIST
CONVERGENCE BECOMES ENHANCED BY THE DEVELOPING GULF BREEZE.

HURLEY

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

24HR QP VT 23/12Z
 0.01 239803 247791 244778 226759 219747 226737 245734 255741
      276761 286763 289764 295762 298761 300759 304755 306752
      312745 331734 341728 348726 357724 363724 371727 374734
      374742 375746 373750 365762 355779 363783 371784 382778
      387771 393763 398756 402749 406740 410732 413725 416718
      420710 424696 426689 426683 427671 422658 424650 429640
      431629 439620 441611 440607 443603 446592 450590 454591
      456593 459598 457607 453616 450623 447627 447631 455637
      459638 463637 470633 473632 479628 482627 490628 494630
      497634 500635 503640 508654 510659 510664 511677 511683
      511689 509697 507708 505713 504718 501727 498734 493758
      492764 492769 490781 488794 487799 487806 486812 486816
      485820 486825 486830 485841 484846 484849 483853 482857
      481864 480874 479878 480885 481899 481908 480915 478922
      477929 474941 473948 470953 465962 460970 457974 453975
      447975 442975 437971 430968 427965 426958 425946 426943
      426937 425930 422927 420916 417906 415900 410896 406894
      399898 390903 384907 364905 361904 356905 350910 344914
      335919 333921 329923 325928 319939 311951 301967 297973
      288974 285969 283959 285940 286932 288924 291910 293901
      294899 297896 301891 302886 304877 305873 310870 315863
      316854 319846 319840 318837 316834 309830 302829 288829
      275826 254816 250815 244816 240816 238811 239803
 0.01 535205 536190 536180 529163 524151 521143 514135 507129
      499117 493113 487108 484103 485099 485094 482092 476092
      472090 468083 461080 456081 447081 440080 433080 432084
      427086 424088 425090 429098 423107 426112 432116 437116
      440117 442120 444123 443128 439135 436141 438144 437146
      435149 435157 442170 446179 441182 442186 441188 439192
      438198 441202 443204 448205 452200 454197 456193 461187
      462184 466180 472179 477185 478193 475200 472202 468204
      466205 462205 451213 448213 444215 440215 434215 427216
      424218 421221 423229 423230 420231 407233 404236 403241
      404245 407249 421258 425260 428264 431269 442268 450274
      454275 458275 468276 477280 494289 501293 506293 508290
      511286 513278 515272 516267 518264 518259 517255 517247
      519239 521225 523222 525220 529216 531212 535205
 0.01 446150 444147 442146 439149 441152 444152 446150
 0.01 407061 407057 407056 404056 401053 401052 398052 395050
      395049 395050 395053 398054 401057 404061 407061 407061
 0.25 494678 492670 488667 484666 479666 473664 466658 457652
      449648 445647 440650 437655 436664 436668 439675 445688
      446692 446695 445700 441708 429719 427723 426730 426735
      423736 420736 417739 415744 414755 412764 409774 406778
      402779 397781 390785 384790 381795 379799 374802 369802
      366805 349812 343818 339824 335829 333835 330845 330849
      331855 335858 341856 349852 350855 349859 346862 340868
      334873 325880 318883 315883 311888 308891 305896 306903
      304907 300913 298922 297926 297931 300937 304937 311933
      318926 325916 330910 337905 342902 347900 356896 363890
      373890 381888 391881 399878 409875 413877 415879 419888
      426898 431912 435917 439918 442917 447912 450910 452904
      456894 458884 461873 465846 472821 475808 476798 478774
      483746 488722 493700 494688 494678
 0.25 523197 520183 518177 521172 522169 522163 521156 517150
      512144 504136 495128 484118 480115 475111 459096 456093
      454091 449090 445091 442092 441095 444100 448103 451105
      452108 451113 451118 453122 455130 459135 465140 465149
      468156 472161 478169 484185 487194 485205 481209 476211
      467213 462213 458215 453215 448217 444217 440218 431222
      430224 432232 431237 425238 421241 426247 445260 451258
      457254 465246 470244 474246 479252 481253 488253 492259
      496264 498264 498259 496255 493250 493244 496242 501245
      505246 507245 511236 512230 511223 508215 506211 506206
      510203 515204 520203 523197
 0.25 491239 490238 490234 489229 486224 486223 484222 481221
      479221 478222 475222 472222 471223 468226 468227 471229
      474229 477230 479233 480235 482237 484240 487240 490239
      491239
 0.25 347753 345750 341750 335751 317757 312762 308768 305772
      301775 292779 285779 279776 267769 244748 242747 238749
      237751 237756 242762 249768 258775 260780 262785 259792
      254797 253803 255807 258809 265812 276815 283815 287810
      291807 296806 301805 312801 321796 327792 332786 338778
      342771 346761 347756 347753
 0.50 484701 483695 480689 475682 473681 469682 465688 463699
      457707 450715 446720 445726 444736 442742 438751 435758
      431778 427786 423790 418794 412798 406798 399797 394796
      390796 385798 381804 376813 376816 377819 381824 383832
      384834 382839 371848 362854 360857 355860 351867 345871
      341873 336876 333878 332881 327885 322890 314890 311891
      309894 310898 311901 312905 310910 308917 311922 315918
      319914 327899 327895 330891 336886 345882 352886 368879
      379875 387871 396868 403865 412864 416865 418869 424883
      429895 435902 439904 443903 447899 449894 451885 453876
      458860 463838 467817 471780 480738 484720 485714 485708
      484701
 0.50 518162 518157 516153 511147 506142 498136 487126 482122
      472120 468120 464122 463123 466126 470131 471137 474141
      481142 485150 486152 483153 480157 481164 488179 491185
      495189 499190 508189 510188 513185 512176 510165 514165
      518162
 0.50 508231 507226 505222 503220 502218 500215 499214 497209
      494212 493217 494221 494226 495229 496231 497232 500232
      500233 501233 503234 506233 508231
 0.50 465239 465234 463229 464224 465221 463218 455217 448219
      442219 439221 438226 438234 434238 431242 435245 441248
      444251 448250 453248 460243 465239
 0.50 427751 426747 426748 427751 428753 427751
 0.50 421814 420813 418811 417811 414812 412814 410819 408823
      407824 407828 410830 411831 413831 416830 418828 419827
      420822 420821 419819 419817 421814 421814
 0.50 381858 380858 377858 374858 371858 369859 366862 366864
      367864 370863 372863 375862 378860 380859 381858
 0.50 341764 341760 340758 336757 329759 321765 313772 308779
      300787 292787 284784 276782 272782 270785 267793 267798
      265799 266801 273803 282805 291802 309794 316792 322789
      325786 332780 338772 341764
 0.50 358834 358830 357827 354823 348824 344828 341833 340837
      338841 338845 342845 346845 348845 352842 355838 358834
 1.00 476717 473714 470715 465715 461719 459721 455730 450745
      448755 447763 445779 445790 445799 441802 437804 434809
      433819 431829 425842 424845 425852 429860 431870 434880
      437886 440887 443884 444879 448865 452846 454837 455830
      454819 452806 454799 456793 463775 469761 470756 469752
      470746 471740 474729 476717
 1.00 513157 511152 507146 503144 498140 495139 492135 486131
      483129 479129 482134 484138 488143 491148 494150 500153
      505155 508158 513157
 1.00 504173 505169 504168 502164 502163 499163 498163 496163
      493166 492166 492171 492172 493176 495178 497181 498181
      500180 502178 504174 504173
 1.00 336767 335766 332767 330769 328772 326774 324776 322779
      319781 317783 320783 322781 325780 327778 329775 332773
      332772 334770 336767 336767
 1.50 460753 459748 458748 457750 456753 456755 455759 455760
      454765 453766 453771 456772 457768 457767 458763 459760
      459758 459753 460753
 1.50 446827 444819 441820 439826 438831 437835 436840 435845
      434853 434857 437861 439860 440855 441846 440842 442837
      445832 446827

$$
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