[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 120543
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU MAR 12 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 5N10W 2N15W CROSSING THE EQUATOR
NEAR 21W THEN CONTINUING WSW ALONG 1S36W 2S44W. SCATTERED
MODERATE CONVECTION IS WITHIN 120 NM N AND 180 NM S OF THE AXIS
BETWEEN 13W-17W. ISOLATED MODERATE CONVECTION IS WITHIN 60 NM
BETWEEN 17W-31W.

...DISCUSSION...

GULF OF MEXICO...
A COLD FRONT IS APPROACHING THE N WATERS EXTENDING ALONG THE
GULF COAST FROM THE FL PANHANDLE TO S TEXAS. LITTLE PRECIP OR
SIGNIFICANT CLOUD COVER IS NOTED ALONG THE WEAK BOUNDARY. THE
UPPER TROUGH SUPPORTING THE FRONT IS EXPECTED TO FLATTEN LATER
TODAY CAUSING THE FRONT TO STALL ACROSS THE FAR NRN WATERS.
GLOBAL MODELS FORECAST ANOTHER TROUGH TO COME INTO PHASE WITH
THE FRONT SAT WHICH MAY PROVIDE SOME SUPPORT TO MAKE IT
PROGRESSIVE. ELSEWHERE...DEEP LAYER RIDGING CENTERED JUST E OF
THE AREA REMAINS IN CONTROL PROVIDING FAIR CONDITIONS AND LIGHT
TO MODERATE ELY SFC WINDS.

CARIBBEAN SEA...
HIGH PRES CENTERED A FEW HUNDRED NM W OF BERMUDA IS PRODUCING
MODERATE TO FRESH TRADES ACROSS THE CARIBBEAN. SFC OBS AND QSCAT
DATA SUGGEST THAT THE STRONGEST FLOW...20-25 KT...IS OVER THE
CENTRAL CARIBBEAN WITH WINDS REACHING 30 KT NEAR THE COAST OF
COLOMBIA. TYPICAL PATCHES OF LOW-LEVEL CLOUDS AND ISOLATED
SHOWERS ARE SCATTERED ACROSS THE AREA. IN THE MID AND UPPER
LEVELS...A TROUGH EXTENDING FROM HISPANIOLA TO THE SW CARIBBEAN
IS THE MAIN FEATURE. CONFLUENCE ALOFT IS ENHANCING SUBSIDENCE
NEAR AND W OF ITS AXIS...WHILE DIFFLUENCE IS 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...
AN OCCLUDED 997 MB LOW PRES SYSTEM HAS MOVED SE INTO THE
DISCUSSION AREA NEAR 30N49W MOVING ESE 15 KT. THE ATTENDANT COLD
FRONT EXTENDS FROM THE TRIPLE POINT NEAR 32N42W EXTENDING S-SW
ALONG 25N45W 22N50W THEN WWD INTO THE SE BAHAMAS. WHILE
LITTLE...IF ANY...PRECIP IS EXPECTED ALONG THE FRONT...
INSTABILITY NEAR THE LOW IS TRIGGERING SCATTERED SHOWERS AND
TSTMS N OF 26N BETWEEN 38W-48W. WINDS TO GALE FORCE ARE BLOWING
N OF 26N W OF FRONT TO 58W DUE TO THE TIGHT PRES GRADIENT
BETWEEN THE LOW AND A SFC RIDGE OVER THE W ATLC. GLOBAL MODELS
SHOW THIS LOW TRACKING ESE AND WEAKENING OVER THE NEXT COUPLE OF
DAYS. AN EVEN DEEPER LOW PRES SYSTEM CENTERED A FEW HUNDRED NM
NW OF THE AZORES CONTINUES TO PULL AWAY FROM THE AREA BUT ITS
TRAILING FRONT STILL EXTENDS SWD FROM 32N29W TO 26N32W. ONLY
SCATTERED SHOWERS ARE POSSIBLE WITHIN 240 NM E OF THE FRONT. IN
THE DEEP TROPICS...STRONG WLY FLOW ALOFT ON THE N SIDE OF A
BROAD UPPER-LEVEL RIDGE IS TRANSPORTING MID-HIGH LEVEL
CLOUDINESS FROM THE LESSER ANTILLES TO WEST AFRICA. DIFFLUENCE
ALOFT ON THE S SIDE OF THE RIDGE IS ENHANCING CONVECTION WITHIN
THE ITCZ E OF 20W.

$$
CANGIALOSI





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