735
FXUS02 KWBC 281833
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
232 PM EDT MON JUL 28 2008
VALID 12Z THU JUL 31 2008 - 12Z MON AUG 04 2008
THE MODELS ARE IN BEST AGREEMENT IN THE HIGH LATITUDES...WHERE
THEY SHOW A DEEP POLAR VORTEX NORTH OF ALASKA/THE YUKON. ENERGY
ROUNDING ITS BASE MOVES A SHORTWAVE RIDGE /SHOWING UP AS A
SIGNIFICANT POSITIVE ANOMALY/ ACROSS NUNAVUT /NORTH CENTRAL
CANADA/ EASTWARD ACROSS THE CANADIAN ARCHIPELAGO. A PROGRESSIVE
DEEP CYCLONE NORMALLY EXISTS 20 DEGREES SOUTH OF SUCH A POSITIVE
ANOMALY /LOWER 50S LATITUDE/. THE MODELS DO NOT DISAPPOINT HERE
ALTHOUGH THE GFS/ECMWF SOLUTIONS LOOK A SHADE TOO FAR TO THE
NORTH. PROGRESSIONWISE...A GENERALLY ZONAL FLOW SHOULD UNDERCUT
THE HIGH LATITUDE RIDGE IN NORTH-CENTRAL CANADA AND LEAD TO A MORE
PROGRESSIVE SOLUTION SUCH AS THE 00Z GFS/00Z NCEP ENSEMBLE MEAN
WITH THE DEEP CYCLONE. THE 12Z NCEP ENSEMBLE MEAN WAS THE MOST
PROGRESSIVE WHILE THE 00Z ECMWF/00Z AND 12Z CANADIAN WERE SLOWER
THAN THE 00Z ECMWF ENSEMBLE MEAN...WHICH SLIGHTLY LAGGED THE 00Z
NCEP ENSEMBLE MEAN/00Z GFS. WENT WITH A BLEND OF THE 00Z GFS/00Z
NCEP ENSEMBLE MEAN SOLUTIONS TO ACCOUNT FOR UNCERTAINTY IN DETAILS
OF THE FORECAST YET YIELD A RELATIVELY PROGRESSIVE PATTERN ACROSS
SOUTHERN CANADA.
ONE FORECAST TO DEVELOP NEAR THE NORTHEAST GULF COAST AND OPEN UP
AS IT RETROGRADES SOUTH OF THE WARM CORE RIDGE ACROSS THE
PLAINS/MIDWEST. THIS SYNOPTIC SITUATION LED TO THE DEVELOPMENT OF
CRISTOBAL LAST WEEK...AND AT THE VERY LEAST SHOULD LEAD TO
ENHANCED RAIN CHANCES ACROSS FLORIDA THIS WEEKEND...WITH HIGHER
THAN AVERAGE CHANCES OF RAIN MOVING WESTWARD ALONG THE GULF COAST
BY EARLY NEXT WEEK...AND ULTIMATELY A SURGE IN THE SOUTHWEST
MONSOON MID TO LATE NEXT WEEK. AFTER COORDINATION WITH TPC...KEPT
A SLOWLY RETROGRESSIVE LOW ACROSS THE FLORIDA PANHANDLE. IF THE
SYSTEM DEVELOPS MORE TO THE SOUTH OR EAST AND IS VERTICALLY
STACKED...IT WOULD MOVE NORTHEAST...WHICH IS A LOW PROBABILITY
ALTERNATIVE SCENARIO AT THIS TIME.
ROTH
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