000
AXNT20 KNHC 101047
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE MAR 10 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1015 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 6N10W 2N15W CROSSING THE EQUATOR 
NEAR 19W THEN EXTENDING WSW ALONG 2S27W 2S44W. SCATTERED 
MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN 150 NM N AND 
45 NM S OF THE AXIS BETWEEN 12W-20W.

...DISCUSSION...

GULF OF MEXICO...
A MID-UPPER LEVEL RIDGE IS SITUATED OVER THE GULF WITH A STREAM 
OF PACIFIC MOISTURE...TRANSPORTED BY A SUBTROPICAL JET...BEING 
DRIVEN AROUND THE RIDGE INTO THE EASTERN CONUS. LITTLE OF THIS 
MOISTURE IS ENTERING THE GULF...IN FACT...WATER VAPOR IMAGERY 
REVEALS WIDESPREAD DRY AIR ACROSS NEARLY THE ENTIRE 
AREA...LEADING TO FAIR CONDITIONS. IN THE LOW LEVELS...A 1023 MB 
HIGH CENTERED NEAR TAMPA BAY IS PROVIDING LIGHT WINDS OVER THE N 
CENTRAL/NE WATERS AND MORE MODERATE 15-20 KT FLOW ELSEWHERE. 
OVERALL...LITTLE CHANGE IS EXPECTED IN THE NEXT DAY OR TWO AS 
THE DEEP LAYER RIDGING REMAINS IN PLACE. A COLD FRONT IS 
FORECAST TO ENTER THE FAR NW WATERS BY MID-WEEK BUT IT WILL 
LIKELY NOT MAKE MUCH PROGRESS...AT LEAST INITIALLY...AS THE 
ASSOCIATED UPPER TROUGH FLATTENS.

CARIBBEAN SEA...
THE PRESSURE GRADIENT BETWEEN A 1023 MB HIGH SITUATED NEAR THE 
NW BAHAMAS AND TYPICAL LOWER PRES OVER N SOUTH AMERICA IS 
PRODUCING A SWATH OF 20-25 KT NE-E TRADES ACROSS MUCH OF THE 
CARIBBEAN BETWEEN 65W-83W. WINDS HAVE NOW DIMINISHED BELOW GALE 
FORCE NEAR THE COAST OF COLOMBIA...AS SUGGESTED BY THE WEAKENING 
PRES PATTERN AND AVAILABLE SFC DATA. SHALLOW CLOUDINESS AND 
EMBEDDED SHOWERS ARE BEING STEERED BY THE LOW-LEVEL FLOW MAINLY 
E OF 70W. IN THE MID AND UPPER LEVELS...A TROUGH EXTENDING FROM 
THE SE BAHAMAS TO HONDURAS IS THE MAIN FEATURE WITH CONFLUENCE 
ALOFT ENHANCING SUBSIDENCE NEAR AND W OF ITS AXIS AND DIFFLUENCE 
CAUSING ONLY SLIGHT MOISTENING E OF THE AXIS. LITTLE CHANGE IN 
THE LARGE SCALE WEATHER PATTERN IS ANTICIPATED OVER THE NEXT DAY 
OR SO.

ATLANTIC OCEAN...
MAIN FEATURE ACROSS THE ATLC DISCUSSION ZONE CONTINUES TO BE A 
LARGE LOW CENTERED NEAR 30N41W...ANALYZED 1000 MB MOVING NE 
AROUND 15 KT. THE LOW HAS LOST MUCH OF ITS FRONTAL STRUCTURE AND 
THE 06Z MAP REFLECTS THIS REPLACING THE COLD FRONT WITH A TROUGH 
FROM 31N38W TO 20N40W AND WELL SW INTO THE DEEP TROPICS TO 
10N49W. A SECONDARY TROUGH EXTENDS SW FROM THE LOW TO 19N49W. 
GALE FORCE WINDS ARE CONFINED TO WITHIN 360 NM OVER THE E 
SEMICIRCLE OF THE LOW. WINDS HAVE DIMINISHED OVER THE W 
SEMICIRCLE DUE TO THE WEAKENING HIGH OVER THE W ATLC...WHICH HAS 
SLACKENED THE LARGE SCALE PRES GRADIENT. SCATTERED SHOWERS AND 
TSTMS ARE LOCATED N OF 24N BETWEEN 35W-41W AND FROM 21N-27N 
BETWEEN 30W-35W ENHANCED BY DIFFLUENCE ALOFT. GLOBAL MODELS ARE 
IN GOOD AGREEMENT IN SHOWING THE LOW ACCELERATING SLIGHTLY NE 
LATER TODAY AS THE NEXT OCCLUDED LOW PRES SYSTEM TRACKS SE INTO 
THE CENTRAL ATLC. ELSEWHERE...A MID-UPPER LOW NEAR THE COAST OF 
MOROCCO AND ASSOCIATED SFC TROUGH IS PRODUCING SCATTERED SHOWERS 
AND ISOLATED TSTMS FROM 28N-31N E OF 13W. CONDITIONS ARE QUIET 
ACROSS THE REMAINDER OF THE AREA. 

$$
CANGIALOSI