Quantitative Precipitation Forecast
Issued by NWS

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343
FXUS04 KWBC 211901
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
201 PM EST TUE FEB 21 2017


PRELIM DAY 1 QPF DISCUSSION
VALID FEB 22/0000 UTC THRU FEB 23/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


FLORIDA

THE LOWER MS VALLEY CLOSED LOW WILL BE TAKING AN UNUSUALLY FAR
SOUTHEASTWARD TRACK DAY 1---PUSHING INTO THE NORTHEAST GULF
TONIGHT/EARLY WEDNESDAY AND TOWARD SOUTHWARD FLORIDA BY WEDNESDAY
EVENING.  MODEL CONSENSUS IS FOR A WELL DEFINED SQUALL LINE TO
PRECEDE THESE HEIGHT FALLS WHERE UPPER DIFFLUENT FLOW---WELL
DEFINED BOUNDARY LAYER CONVERGENCE AND ABOVE AVERAGE PW VALUES
WILL COINCIDE.  THIS SQUALL LINE WILL PRIMARILY IMPACT THE
PANHANDLE REGION INITIALLY---APPROACHING THE WEST TO SOUTHWEST
COAST AROUND SUNRISE---PUSHING ACROSS SOUTH FLORIDA DURING THE
MORNING AND AFFECTING THE SOUTHEAST TO EAST COAST LATE MORNING
INTO THE AFTERNOON.    THERE ARE SOME TIMING DIFFERENCES WITH THE
EASTWARD PUSH OF THIS POTENTIAL CONVECTION---WITH WPC LEANING
TOWARD THE FASTER SOLUTIONS GIVEN THE BIAS---ESPECIALLY OF THE
SOME OF THE HI RES GUIDANCE TO BE SLOW TO PUSH ORGANIZED ACTIVITY
DOWNSTREAM.  THE DAY 1 QPF DID FOLLOW THE HI RES QPF DISTRIBUTION
SHOWING A MAX FROM THE PANHANDLE AND ALONG THE WEST TO SOUTHWEST
FL COAST AND ANOTHER ALONG THE SOUTHEAST TO EAST COAST WHERE
BOUNDARY LAYER CONVERGENCE MAXIMA MAY SET UP.

SOUTHERN-CENTRAL APPALACHIANS---OH VALLEY INTO THE NORTHEAST

TO THE NORTH AND NORTHEAST OF THE GULF SYSTEM---A WEAKENING
FRONTAL BOUNDARY STRETCHING FROM THE MID MS VALLEY INTO THE GREAT
LAKES WILL BE WEAKENING AND DISSIPATING EARLY DAY 1. AN AXIS OF
ABOVE AVERAGE PW VALUES WILL REMAIN ALONG AND AHEAD OF THIS
DISSIPATING SYSTEM.   HOWEVER---WITH THE OVERALL WEAKENING OF THE
LARGE SCALE FORCING---ANY PRECIP IS EXPECTED TO BE ON THE LIGHT
SIDE.

CENTRAL TO NORTHERN CALIFORNIA---PACIFIC NORTHWEST---GREAT BASIN
INTO THE CENTRAL TO NORTHERN ROCKIES

BROAD CYCLONIC FLOW WILL PERSIST DAY 1 ACROSS A LARGE PORTION OF
THE WESTERN U.S. THIS PERIOD.  PRECIPITATION INTENSITY AND AMOUNTS
WILL BE LESS THAN PREVIOUS DAYS AS THIS TROFFING WILL NOT BE ABLE
TO TAP ANY SIGNIFICANT MOISTURE SOURCE---PW VALUES NEAR SEASONAL
TO SLIGHTLY BELOW AVERAGE.   THIS WILL LIKELY KEEP AREAL AVERAGE
PRECIP TOTALS IN THE MODERATE RANGE---WITH .25-.50"+ AMOUNTS IN
THE FAVORED TERRAIN AREAS FORM THE CENTRAL TO NORTHERN
SIERRA---NORTHWEST CALIFORNIA COAST RANGE NORTHWARD INTO THE
OREGON/WASHINGTON COAST RANGE---THROUGH THE OREGON-WASHINGTON
CASCADES AND INLAND FROM THE WASATCH INTO THE CENTRAL TO NORTHERN
ROCKIES.

NORTHERN PLAINS INTO THE UPPER MS VALLEY

MID TO UPPER LEVEL HEIGHT FALLS WILL BE PUSHING EASTWARD OUT OF
THE MEAN WESTERN TROF AND ACROSS THE NORTHERN PLAINS INTO THE
UPPER MS VALLEY DAY 1.  THERE IS A LOT OF MODEL QPF DETAIL SPREAD
WITH THE AXIS OF MODERATE PRECIP TOTALS EXPECTED TO STREAK
EASTWARD FROM NORTHEAST MT ACROSS ND AND INTO NORTHERN
MN---LEADING TO LOW CONFIDENCE WITH THESE DETAILS.

...CENTRAL-NORTHERN CA INTO THE NORTHERN ROCKIES...

GUIDANCE REASONABLY AGREES THAT A MAIN LOW REACHING THE OR COAST
THIS MORNING...SUPPORTING IMPULSE/JET ENERGY ALOFT...AND LEAD
BAROCLINIC LEAF EXPANSION INLAND AND OVER THE NWRN U.S. TODAY WILL
SUPPORT A WIDESPREAD SWATH OF MODERATE TO TERRAIN ENHANCED
PCPN/ELEV SNOWS ACROSS THE REGION. INCREASED WPC CONTINUITY
ACCORDINGLY TO ADDRESS RECENT SATELLITE AND MODEL
TRENDS...ESPECIALLY AS PER THE MESO MODELS. THIS INCLUDES SOME
1-2" LIQUID AMOUNTS DAY1 FOR SW OREGON INTO THE OREGON
CASCADES...WITH DECREASING ACTIVITY INTO TUE NIGHT WITH MAIN
LOW/SHORTWAVE PASSAGE. FOR DETAILS ON WINTER WEATHER AT HIGHER
ELEVATIONS AND INLAND ACROSS THE NRN INTERMOUNTAIN WEST ROCKIES AS
DYNAMICS/HEIGHT FALLS SQUEEZE OUT PCPN...PLEASE SEE THE WPC WINTER
WEATHER DESK QPFHSD DISCUSSION FOR MORE DETAILS.

FARTHER SOUTH UNDERNEATH...GUIDANCE ALSO AGREES THAT WHILE
ADDITIONAL ERN PACIFIC RIPPLES ALOFT WILL CONTINUE TO FEED UPON A
DECAYING ATMOSPHERIC RIVER MOISTURE FEED THROUGH TUE IN THE WAKE
OF MAIN MID-UPPER TROUGH/JET SUPPORT...THE BULK OF HEAVY PCPN FOR
N-CENTRAL CA WILL ON A DECIDEDLY DOWNWARD TREND AS THE
AFOREMENTIONED MID-UPPER LEVEL TROUGH PROGRESSES INLAND. LINGERING
MECHANICS THOUGH REMAIN IN PLAY FOR ADDITIONAL RAINFALL AND HIGHER
ELEVATION SNOWS ACROSS CENTRAL-NRN CA...PARTICULARLY INTO THE
CENTRAL SIERRA WHERE TOPOGRAPHIC LIFT ENHANCES LIFT WITH THE
LINGERING MOISTURE PLUME. AGAIN...PLEASE SEE THE WPC WINTER
WEATHER DESK QPFHSD DISCUSSION FOR MORE DETAILS.


...CENTRAL GULF COAST STATES...

THERE IS IMPROVED MODEL AGREEMENT THAT THE INITIALLY FULL-LATITUDE
UPPER TROUGH WILL SPLIT WITH A VIGOROUS SRN STREAM TROUGH
DEEPENING AND CLOSING OFF WITH NEG TILT AT MID LEVELS ON A GRADUAL
BUT STEADY ESEWD TRACK INTO THE LOWER MS VALLEY TO THE GULF OF
MEXICO TUE INTO WED. FAVORABLE UPPER DIFLUENCE AND LINGERING
INSTABILITY/MOISTURE INLAND OVER THE E-CENTRAL GULF COAST STATES
SHOULD STILL PROVIDE PRE-FRONTAL CONVECTION WITHIN AN AREA OF
MODEST TO LOCALLY HEAVY POCKETS OF PRECIP THAT MAY LEAD TO RUNOFF
ISSUES GIVEN PWS AOA 1.25". EXPECT SOME WIDESPREAD 1" AMOUNTS
CENTERED OVER SRN AL AND THE FL PANHANDLE...WITH BEST POTENTIAL
FOR 2-3" VALUES CLOSER TO THE COAST AND ESPECIALLY OVER THE NERN
GULF OF MEXICO. FOLLOWED A GLOBAL AND MESO MODEL COMPOSITE BLEND
THAT SEEMS REASONABLY WELL CLUSTERED AND IN LINE WITH WPC
CONTINUITY.


...MIDWEST / GREAT LAKES...

SHORTWAVE TROUGH AND ASSOCIATED SURFACE SYSTEM PROGRESSION ACROSS
THE OH VALLEY/GREAT LAKES AND NORTHEAST WILL HAVE LESS MOISTURE TO
CONTEND WITH BUT FAVORABLE LEAD THETAE FLOW AND DYNAMIC SUPPORT
WILL SUPPORT A
SUUPORT A SWATH OF LIGHT TO LOCALLY MDT PCPN ACROSS THE REGION AS
PER A FAVORED MODEL CONCENSUS.

SCHICHTEL

GRAPHICS AVAILABLE ON THE WEB AT
WWW.WPC.NCEP.NOAA.GOV/QPF/QPF2.SHTML

24HR QP VT 23/00Z
 0.01 216829 218829 219828 221829 221831 221833 220835 219837
      218839 218841 218843 218845 222865 224869
      225867 228865 233866 239870 246874 254875 265875 272878
      281879 285878 292877 298876 306877 310878 312881 317883
      322885 328890 331895 329900 313909 300917 299921 301924
      307928 316928 320925 325924 335923 342922 346919 350914
      353905 353900 351897 347886 347882 349879 351876 354872
      359868 365864 368863 371864 373869 373882 374887 377890
      379891 381887 385879 393863 400846 402836 401831 405829
      425822 431816 433813 433805 434801 433797 434795 436784
      439775 441763 442759 444755 452751 470747 475747 476754
      477761 476768 476775 475782 475799 473805 473812 474828
      476843 477850 478856 479871 477876 473875 469872 465873
      461882 459892 460906 460932 460942 460956 457982 456017
      456025 457032 458036 458044 459049 459058 457062 456065
      454064 455050 455043 454038 452034 448034 442033 440035
      426044 416056 410054 406051 401050 398053 395057 391059
      386058 384061 382064 384068 382069 378064 370059 365059
      363062 364064 369070 371081 373085 376087 379087 382089
      385091 389091 389086 387083 385079 387079 392084 395087
      396088 398086 403087 403091 405096 404102 404105 401105
      398108 379117 370122 365121 363123 364126 369127 376133
      381134 382136 381137 382145 385149 386155 389164 391172
      390178 389187 387190 384189 381186 372183 361181 355181
      351182 346184 345191 346196 349196 354195 358192 361191
      365193 371200 378205 385209 392216 397221 399225 394225
      389223 386221 377217 375214 371212 366209 363207 359204
      353204 352212 354216 360226 362231 367234 371236 374240
      380245 388250 398253 407256 416257 426257 439255 449254
      453253 457254 461253 466255 472260 483277 490289 500290
      504287 506284 507279
 0.01 507279 507274 506271 502265 499259 496252 494245 492239
      481230 476225 480224 483225 490227 493228 496226 499216
      496209 494207 490205 483203 471205 467207 461205 453211
      446213 443213 442208 447204 450200 453199 455199 458197
      461193 466187 471181 484172 499150 504154 508159 516169
      518173 522175 528169 529156 530145 526128 521109 492066
      494043 498021 502978 503955 503932 504913 503903 502898
      502893 503883 506873 509862 510851 513841 514833 516816
      518796 517786 515778 515772 513770 511765 506761 502754
      498747 494741 487739 481742 483725 483720 481717 475714
      471715 472711 476705 479699 480691 481682 482680 481675
      481670 478668 475669 459692 454698 446702 444705 438707
      430709 424713 422715 422718 419724 417727 416723 415714
      412706 410699 406693 402694 400698 400704 401707 405729
      407737 408749 404764 401769 397774 387783 377787 374785
      371785 366789 356798 352802 349804 345804 341805 338803
      335801 333797 327792 319789 307786 296781 286776 281773
      278771 274771 267770 256772 247773 241774 238776 227782
      218792 214798 209805
 0.01 464094 461089 456086 452083 449080 442081 437082 434088
      435090 438091 442091 448092 450091 454093 457098 460098
      463097 464094
 0.01 443176 441170 438165 434160 432154 433147 436138 439135
      443132 444128 443126 441122 439122 438117 435119 432124
      429129 426136 425145 425153 425157 427160 430166 432173
      430178 432184 435186 438185 443176
 0.01 430197 431195 429193 428194 428197 429199 430197
 0.25 482247 482245 482242 482241 481239 481237 480236 479234
      478233 476233 474233 472234 471236 471238 471241 471242
      473244 474245 476246 477247 479248 481248 482247
 0.25 480216 482214 480212 479212 477212 476212 475212 474214
      475216 477216 478216 480216 480216
 0.25 485136 484134 484133 483132 481131 479131 478129 476127
      475126 473125 472126 472128 472131 472133 473133 474135
      476136 477137 479138 480138 482138 483138 484136 485136
 0.25 486103 485094 484085 482077 481070 481065 483062 483057
      483047 482024 484005 484979 485968 486960 489950 491942
      492930 491919 491913 489909 487909 485912 482920 481929
      480940 480952 477971 476982 476994 476005 478014 478025
      478037 476057 475080 474096 474102 472106 471108 474110
      479110 481109 486103
 0.25 477159 476155 472151 468144 463142 459145 457147 457152
      455155 452151 449149 443148 440151 439156 440159 444162
      452164 456160 459159 464161 468164 472164 476162 477159
 0.25 462243 464238 462236 456231 452234 445234 438234 436233
      437228 439226 439223 437220 433218 427218 424220 422223
      419224 415222 412216 408210 403205 389198 379190 371187
      368189 369192 378202 390211 401218 408219 409223 409226
      405231 399232 394238 394242 397245 402248 409249 424250
      430249 436245 442242 449242 457244 462243
 0.25 463178 463176 462176 461176 459176 458177 457177 456178
      455179 454181 454184 455185 457185 457184 458184 460183
      460182 462181 462179 463178
 0.25 448111 448106 446104 439099 436098 434095 430089 427086
      425086 424091 426095 427098 426100 420102 417104 414104
      411101 408100 405108 400112 397114 396119 402125 406124
      409122 413121 427117 431113 434110 438111 444113 448111
 0.25 414073 414067 410064 407063 403065 401069 397069 394073
      397077 401076 403072 406072 411075 414073
 0.25 390838 390834 389831 385829 380831 376832 374837 375840
      374845 374848 379850 385848 387845 389840 390838
 0.25 378078 377076 376071 375069 375066 371064 370063 367063
      369066 371067 373070 374073 375075 376078 378078
 0.25 374817 375814 374810 373805 367806 366809 364814 363819
      361823 363826 367828 371829 372824 373819 374817
 0.25 326848 326843 323840 316838 313837 312830 311824 312818
      313815 316813 318809 318808 305799 293792 285788 278784
      271782 264781 245787 237789 231792 226799 221805 219812
      220816 222819 225821 227825 231832 228839 227842 228846
      236848 245847 249846 250847 244852 243855 245859 251863
      259864 268865 286868 294869 303869 311864 317859 326848
 0.50 418242 418240 417239 416237 414236 412236 411236 409237
      408237 407238 406239 405240 406242 408243 409243 411243
      412243 413243 415243 417242 418242
 0.50 415118 416116 415113 414112 412110 410108 409104 407107
      407110 405112 403115 402118 404119 407119 410119 413119
      415118
 0.50 401213 399208 394204 389200 384196 380192 374190 372190
      373193 377198 381202 385205 390208 394212 397215 401213
 0.50 316851 290837 293836 298835 301834 300828 296821 290818
      300817 304815 306812 306807 303804 296799 284792 276787
      268785 263785 259787 251789 242792 233795 227800 224807
      223811 226813 234812 236815 236821 236829 233838 235842
      239843 247841 255838 260838 264839 267841 263843 260846
      258849 258854 260858 264862 268863 277863 285865 295865
      303865 310860 315856 316851
 0.50 286812 284811 282810 280809 277807 274806 272806 269805
      265806 264809 266811 268813 271814 273814 277814 280813
      282812 284813 286812
 1.00 302855 301852 298850 290848 285845 282844 280843 277844
      272848 268849 266851 267856 269857 277859 284860 293860
      300858 302855
 1.00 297809 294805 289801 279797 268794 263794 255795 250796
      244800 242805 243807 245805 249806 255804 266799 272800
      277803 287808 292809 297809
 1.00 286831 287828 285825 283822 275818 264819 257817 252817
      248819 243825 245827 250828 260829 267832 275835 285833
      286831
 1.50 295853 294853 293852 291851 289850 288850 287849 285849
      283848 281849 280850 280852 279852 279854 280855 282856
      283856 284857 286857 287857 289857 291857 293856 294855
      294854 295853
 1.50 279828 278826 277826 276825 274826 275828 276829 278829
      279828

$$





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