[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 172330
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE MAR 17 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 5N8W 3N19W 1N31W CROSSING THE
EQUATOR NEAR 36W EXTENDING TO NE BRAZIL NEAR 3S45W. NUMEROUS
MODERATE CONVECTION IS S OF 4N BETWEEN 11W-14W. SCATTERED
MODERATE CONVECTION IS FROM 3N-5N BETWEEN 19W-26W AND S OF 3N
BETWEEN 29W-33W.

...DISCUSSION...

GULF OF MEXICO...
A WEAKENING COLD FRONT IS DRIFTING S OVER SOUTH FLORIDA THEN
BECOMES STATIONARY OVER THE ERN GULF FROM 26N83W TO 24N92W. A
1017 MB FRONTAL WAVE HAS FORMED ALONG THE BOUNDARY NEAR 26N86W.
SATELLITE IMAGERY AND DOPPLER RADAR SHOW BROKEN TO OVERCAST
SKIES AND EMBEDDED SCATTERED SHOWERS FROM 24N-29N E OF 88W.
THERE COULD BE AN ISOLATED TSTM JUST E OF THE WEAK LOW AS
SUGGESTED BY ENHANCED CLOUDS ON IR IMAGERY. HOWEVER...IN GENERAL
MUCH OF THIS MOISTURE IS SHALLOW IN NATURE CAPPED BY WIDESPREAD
STABLE AIR ALOFT. SFC WINDS ARE LIGHT...EXCEPT FOR MODERATE NE
WINDS N OF THE FRONT BETWEEN 85W-92W. WHILE THE FRONT IS
WEAKENING...REMNANT SFC TROUGHING IS EXPECTED TO REMAIN OVER THE
E/CNTRL GULF OVER THE NEXT COUPLE OF DAYS KEEPING THE POTENTIAL
FOR SHOWERS/TSTMS.

CARIBBEAN SEA...
TRANQUIL WEATHER CONDITIONS PREVAIL ACROSS THE CARIBBEAN.
WIDESPREAD SUBSIDENCE IS BEING ENHANCED BY CONFLUENCE ALOFT
ALONG AND TO THE W OF AN UPPER TROUGH AXIS THAT EXTENDS FROM THE
NRN LEEWARD ISLANDS TO VENEZUELA. AT THE SFC...THE PRESSURE
GRADIENT BETWEEN A 1020 MB HIGH NEAR 25N57W AND LOWER PRES OVER
NRN SOUTH AMERICA IS PRODUCING A SWATH OF 20-25 KT ELY TRADES
ACROSS MUCH OF THE CENTRAL AND E CARIBBEAN. THESE WINDS MAY
REACH 30 KT IN THE TOPOGRAPHICALLY ENHANCED ZONE NEAR THE COAST
OF COLOMBIA. TRADE WINDS ARE FORECAST TO WEAKEN SLIGHTLY WED AS
THE HIGH SHIFTS E IN RESPONSE TO DEEPENING LOW PRES OVER CENTRAL
ATLC.

ATLANTIC OCEAN...
LOW PRES N OF THE DISCUSSION AREA NEAR 35N68W IS DRAGGING A COLD
FRONT FROM 32N70W TO SOUTH FLORIDA. LOW-MID LEVEL CLOUDS AND
EMBEDDED SHOWERS ARE LOCATED WITHIN 90 NM OF THE FRONT. ASCAT
DATA SHOWS ENHANCED 20-25 KT SW TO W FLOW NEAR OUR N BORDER...ON
THE S PERIPHERY OF THE LOW...AND NLY 15-20 KT WINDS NW OF THE
FRONT. A WARM FRONT EXTENDS SE FROM THE LOW TO 31N55W AND
CONNECTS WITH A COLD FRONT...ASSOCIATED WITH A GALE CENTER NEAR
37N37W...ALONG 29N45W 31N40W. SCATTERED SHOWERS ARE LIKELY N OF
THE FRONT. A 1006 MB BROAD LOW IS CENTERED ABOUT 240 NM W OF THE
MADEIRA ISLANDS NEAR 31N21W. ONLY ISOLATED SHOWERS ARE NOTED
WITHIN 420 NM OF THE LOW AS THE FEATURE LACKS MUCH UPPER
SUPPORT. THIS WEAK FEATURE IS EXPECTED TO BECOME ABSORBED BY THE
STRONGER AND MORE PROGRESSIVE LOW TO ITS E. FARTHER S...
INCLUDING MOST OF THE SUBTROPICS/TROPICS...A WEAK SFC RIDGE
EXTENDING SE FROM A 1020 MB HIGH NEAR 26N57W AND GENERALLY ZONAL
FLOW ALOFT IS PROMOTING MAINLY FAIR WEATHER AND LIGHT TO
MODERATE SFC WINDS.

$$
CANGIALOSI





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