[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 100535
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 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 LOCATED OVER THE GULF OF MEXICO WITH
A STREAM OF PACIFIC MOISTURE...TRANSPORTED BY A SUBTROPICAL
JET...BEING DRIVEN N AND E ACROSS 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. 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 HIGH PRES 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 ARE STILL BLOWING UP TO GALE FORCE NEAR
THE COAST OF COLOMBIA...BUT WILL LIKELY BE DIMINISHING BELOW
THAT CRITERIA SHORTLY AS THE HIGH WEAKENS AND DRIFTS N. THIS
STIFF LOW-LEVEL FLOW IS DRIVING SHALLOW CLOUDINESS AND EMBEDDED
SHOWERS ACROSS THE E CARIBBEAN 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.

ATLANTIC OCEAN...
MAIN FEATURE ACROSS THE ATLC DISCUSSION ZONE CONTINUES TO BE A
LARGE OCCLUDED LOW CENTERED NEAR 28N44W...ANALYZED 1000 MB
MOVING NE AROUND 15 KT. THE LOW HAS GENERALLY CHANGED LITTLE IN
STRUCTURE OVER THE PAST 24 HOURS WITH CONVECTION LIMITED TO THE
N AND E PORTIONS OF THE SYSTEM. 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 PRES GRADIENT. AN
OCCLUDED/COLD FRONT EXTENDS FROM 32N38W TO 20N40W AND WELL SW
INTO THE DEEP TROPICS TO NEAR 7N55W. SCATTERED SHOWERS AND TSTMS
ARE LOCATED WITHIN 180 NM OF THE FRONT N OF 25N AND FROM 20N-25N
BETWEEN 34W-41W ENHANCED BY DIFFLUENCE ALOFT. GLOBAL MODELS ARE
IN GOOD AGREEMENT IN SHOWING THE LOW ACCELERATING NE LATER TODAY
AS THE NEXT OCCLUDED LOW PRES SYSTEM TRACKS SE INTO A SIMILAR
AREA BY WED. ELSEWHERE...A MID-UPPER LOW NEAR THE COAST OF
MOROCCO IS PRODUCING SCATTERED SHOWERS AND TSTMS FROM 28N-31N E
OF 14W...WHICH INCLUDES THE ERN CANARY ISLANDS. CONDITIONS ARE
QUIET ACROSS THE REMAINDER OF THE AREA AND TRADE WINDS ARE
SIGNIFICANTLY REDUCED DUE TO THE PRESENCE OF THE LARGE LOW IN
THE SUBTROPICS.

$$
CANGIALOSI




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