000
FXUS02 KWBC 291750
PMDEPD
 
EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
150 PM EDT FRI AUG 29 2008
 
VALID 12Z MON SEP 01 2008 - 12Z FRI SEP 05 2008
 
CONSIDERING THE REASONABLE AGREEMENT BETWEEN THE 00Z/29 GFS...GEFS
MEAN...AND THE 00Z ECMWF...AS WELL AS THE 12Z/28 AND 00Z/29 ECMWF
ENSEMBLE MEAN...WITH THE MAIN FLOW ACROSS THE NORTHERN TIER OF
STATES DURING THE MEDIUM RANGE PERIOD...WILL BE MAKING THE MOST
CRITICAL EDITS FOR THE PRELIMINARY MANUAL GRAPHICS BASED ON HOW
THE GUIDANCE IS HANDLING THE POTENTIALLY HIGH IMPACT TROPICAL
SYSTEMS.  THE 00Z/29 ECMWF IS CLOSEST TO THE 03Z/29 TPC GUIDANCE
FOR GUSTAV THROUGH DAY 5...SO WILL USE ITS MASS FIELDS AS A BASIS
FOR THE FRONTS AND PRESSURES. WILL BRING THE LOW CENTER N AND THEN
NE DAYS 6 AND 7 THU/FRI AROUND THE ECMWF/AND ECMWF ENS MEAN MID
LEVEL RIDGE AND THEN ACCELERATE NEWD WITH THE APPROACH OF THE WRN
TROF. 

THE BIGGEST EDIT TO THE ECMWF FIELDS WILL BE WITH HANNA...WHICH IS
TO SUPRESS AND SLOW THE ECMWF. MOST DYNAMICAL MODELS..00Z/06Z
GFS/ECMWF/NGPS/UKMET WITH THE EXCEPTION OF 00Z CMC THREATEN THE
BAHAMAS/FLORIDA/CUBA WITH THIS SYSTEM. NEW 12Z CMC NOW THREATENS
BAHAMAS AND FLORIDA. HURRICANE GUIDANCE MODELS BY DAY 5 SUGGEST A
STALL AND ARE VERY UNDETERMINED IN FUTURE TRACK. UPDATED PRELIMS
AND FINALS FOLLOW DYNAMICAL MODEL SCENARIO EXTRAPOLATING HANNA TO
THE SOUTHWEST INTO THE CENTRAL BAHAMAS AND FLORIDA STRAIT. THIS IS
A SLOWER SOLUTION THAN ECMWF/UKMET/GFS. SEE TPC
ADVISORIES/DISCUSSIONS FOR GUSTAV AND HANNA.

WIDESPREAD SOUTHWEST AND ROCKIES RAINFALL DAYS 2-3 AS THE DIGGING
WRN TROF LIFTS DEEP MOISTURE NWD WELL IN MT MON-WED.  

HURRICANE CONDITIONS FORECAST FOR THE CENTRAL GULF COAST FOCUSSING
ON LA EARLY IN THE WEEK
WITH A SLOWLY DECAYING SYSTEM BRING HVY RAINS INTO LA/E TX AND NWD
INTO OK/AR AND THEN NEWD MID TO LATE WEEK. 

TROPICAL STORM OR HURRICANE CONDITIONS POSSIBLE FOR THE BAHAMAS
AND SRN FL/CUBA LATE NEXT WEEK AS A MODEL CONSENSUS TRACK OF HANNA
TAKES IT THRU THE FLORIDA STRAIT. FORECAST TRACK AND TIMING ERRORS
MAY BE LARGE. SEE LATEST NHC ADVISORIES/WARNINGS/DISCUSSIONS FOR
BOTH GUSTAV AND HANNA.
CISCO/ROSENSTEIN
$$