Prognostic Meteorological Discussion
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FXUS02 KWBC 251600
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1159 AM EDT THU AUG 25 2016

VALID 12Z SUN AUG 28 2016 - 12Z THU SEP 01 2016

...A POSSIBLE TROPICAL SYSTEM THREAT BEING MONITORED FOR THE
BAHAMAS AND SERN US/GULF OF MEXICO...


...GUIDANCE/UNCERTAINTY ASSESSMENT AND WEATHER
HIGHLIGHTS/THREATS...

MODEL AND ENSEMBLE MEAN MASS FIELDS OVERALL AGREE AT MID-LARGER
SPATIAL SCALES ACROSS MUCH OF THE NATION AND FOR THE MOST PART A
GUIDANCE COMPOSITE OR ENSEMBLE MEAN SOLUTION SEEMS REASONABLE
BEYOND LESS PREDICTABLE AND CONVECTION CONTINGENT SMALLER SCALE
FEATURES/INTERACTIONS. THE MOST SIGNIFICANT RUN TO RUN CONTINUITY
ISSUE AND GUIDANCE DIFFERENCE IS WITH TROPICAL DEVELOPMENT
POTENTIALLY EFFECTING THE GULF OF MEXICO AND FL/SERN US THAT IS
NOW BEING FOLLOWED NEAR THE TURKS AND CAICOS ISLANDS BY THE
WEATHER PREDICTION CENTER AND THE NATIONAL HURRICANE CENTER. THE
SITUATION IS FLUID BUT DOMINANT GUIDANCE CLUSTERING HAS SHIFTED
SIGNIFICANTLY TO NORTHEAST COMPARED TO YESTERDAY TOWARD SRN
FL...THE ERN GULF OF MEXICO...AND SERN US NEXT WEEK IN A PATTERN
WITH WEAKER BLOCKING MID-UPPER LEVEL RIDGING OVERTOP OVER THE
MID-ATLANTIC AND VICINITY. WPC PROGS SHOW A CONSERVATIVE LOW
STRENGTH/TRACK INCORPORATING ABOUT TWO-THIRDS OF THE CONTINUITY
CHANGE FROM YESTERDAY WITH THE IDEA THAT THE RIDGE WEAKENING
CHANGE OVERTOP MAY BE MORE SUBTLE. THIS SOLUTION IS CLOSEST TO THE
00 UTC ECMWF ENSEMBLE MEAN.

ELSEWHERE...VORTS/WEAKNESS ENERGIES ALOFT OVER THE MONSOONAL SWRN
US ALSO FEED INTO THE S-CENTRAL US TO FOCUS LOCAL CONVECTIVE RAINS
THROUGH THE WEEKEND INTO MID NEXT WEEK. UNSETTLING TROUGH
AMPLIFICATION AND SOME TERRAIN BASED SHOWER SUPPORT GRADUALLY
INLAND FROM THE WEST/NWRN US COAST BY MIDWEEK MAY ALSO PUMP SOME
LEAD MOISTURE THROUGH THE INTERMOUNTAIN WEST AND ROCKIES.
MEANWHILE OVERTOP...A SERIES OF HARD TO TIME IMPULSES RUNNING
EWD/SEWD FROM SRN CANADA AND THE US NRN TIER WILL ACT TO FORCE
SEVERAL CONVECTION FOCUSING SURFACE FRONTAL SURGES ACROSS THE
N-CENTRAL THROUGH NERN US.

SCHICHTEL






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