[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 091044
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON APR 09 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND THE 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
1045 UTC.

...THE ITCZ...
AXIS IS CENTERED ALONG 7N12W 4N20W 2N30W CROSSING THE EQ AT 40W
AND CONTINUING INTO NE BRAZIL NEAR 2S48W. SCATTERED MODERATE IS
WITHIN 120 NM N OF THE AXIS BETWEEN 19W-24W. ISOLATED MODERATE
IS WITHIN 150 NM N OF AXIS W OF 32W.

...DISCUSSION...

THE GULF OF MEXICO...
A SWATH OF LOW AND MID LEVEL CLOUDS WITH EMBEDDED SCATTERED
STRATIFORM PRECIP COVERS MUCH OF REGION N OF 26N. THIS IS
ASSOCIATED WITH OVERRUNNING MOISTURE ALONG AND TO THE N OF A
WARM FRONT THAT STRETCHES FROM 27N85W TO A 1014 MB LOW NEAR
26N95W. A DISSIPATING STATIONARY FRONT EXTENDS SWD FROM THE LOW
TO 20N96W THEN CURVES BACK NWD BANKED AGAINST THE SLOPES OF THE
SIERRA MADRE MOUNTAINS IN MEXICO. THIS FRONTAL SYSTEM HAS
PRODUCED A FAIRLY DRAMATIC CONTRAST IN TEMPS RANGING FROM NEAR
50 F ACROSS THE GULF COAST TO THE LOW TO MID 70'S IN THE WARM
SECTOR. IN ADDITION...THE INTERACTION BETWEEN THE SFC LOW AND
HIGH PRES OVER ERN TEXAS HAS LED TO PERSISTENT STRONG NE WINDS
AND WIND WAVES IN THE NW GULF...WHICH HAS PROMPTED A HIGH SURF
ADVISORY FOR BEACHES ALONG S TX. SEE STATEMENTS FROM WFO
BROWNSVILLE FOR MORE INFO. MAINLY FAIR CONDITIONS CONTINUE
ACROSS THE SE GULF SUPPORTED BY SFC HIGH PRES CENTERED N OF THE
BAHAMAS. IN THE MID AND UPPER LEVELS...THE FLOW IS ZONAL ACROSS
THE NRN HALF AND WSW ACROSS THE SRN. THE WSW FLOW IS
TRANSPORTING A STREAK OF CIRRUS SE OF A LINE FROM TAMPICO TO FT
MYERS. IT DOES APPEAR THAT THE HIGH CLOUDS SHOULD THICKEN THRU
THE DAY AS AN ABUNDANT FEED IS POURED INTO THE SW GULF.

OVER THE NEXT COUPLE OF DAYS...NWP MODELS SHOW THE WEAK LOW AND
FRONT LIFTING N AND BECOME INCREASINGLY ZONAL IN STRUCTURE. THIS
WILL HELP TO DESTABILIZE MUCH OF THE GULF AS MOIST LOW-LEVEL SLY
FLOW DEVELOPS TARGETING SHOWERS AND TSTMS ACROSS THE N CENTRAL
AND NE GULF.

THE CARIBBEAN SEA...
A BROAD MID TO UPPER LEVEL RIDGE COVERS THE REGION ANCHORED BY
AN UPPER HIGH CENTERED NEAR THE ABC ISLANDS. SLY FLOW ON THE W
SIDE OF THE UPPER ANTICYCLONE AS WELL AS LOW-LEVEL
CONVERGING FLOW ALONG THE ITCZ AXIS IS FUELING PATCHES OF
MODERATE TO STRONG CONVECTION OVER COLOMBIA. LEFT OVER HIGH
CLOUDS ARE BEING PUSHED NWD INTO THE S CARIB W OF 70W BY THE SLY
FLOW. IN THE LOWER LEVELS...LIGHT TO MODERATE TRADES DOMINATE AS
THE GRADIENT IS STILL FAIRLY LOOSE IN RESPONSE TO THE RECENT
FRONTAL BOUNDARY THAT IS NOW MOSTLY N OF THE AREA. HOWEVER...A
BROKEN DECK OF LOW-MID LEVEL CLOUDS AND LIKELY SCATTERED SHOWERS
LIE OVER THE ISLAND OF HISPANIOLA ASSOCIATED WITH THE FRONT'S
REMNANT MOISTURE AND LOCAL TOPO AND ONSHORE FLOW INFLUENCES.
LOOKING AHEAD A COUPLE OF DAYS...THE TRADES MAY INCREASE
SLIGHTLY AS THE FRONT DISSIPATES AND A NARROW WEAK SFC RIDGE
BUILDS N OF THE AREA.

THE ATLANTIC OCEAN...
WEAK SFC HIGH PRES...ANALYZED 1022 MB N OF THE CENTRAL BAHAMAS
NEAR 27N73W...IS BUILDING E ACROSS THE WRN ATLC BEHIND A
STATIONARY FRONT THAT ENTERS THE AREA NEAR 32N51W AND CONTINUES
SW TO THE N SHORE OF HISPANIOLA NEAR 20N70W. BROKEN TO OVERCAST
MULTILAYERED CLOUDS WITH EMBEDDED SCATTERED SHOWERS ARE WITHIN
150 NM EITHER SIDE OF THE FRONT. THERE IS NOT MUCH UPPER SUPPORT
FOR THIS SFC FEATURE...WITH THE FLOW BEING MAINLY SWLY IN THE SW
ATLC. MOST OF THE DYNAMICS/UPPER ENERGY IS LOCATED WELL N OF THE
REGION AND FOR THAT REASON...THE BOUNDARY WILL GRADUALLY
DISSIPATE THROUGH MID-WEEK WITH A WEAK E-W SFC RIDGE TAKING ITS
PLACE.

THE MID AND UPPER LEVEL PATTERN IN THE CENTRAL AND ERN ATLC IS
HIGHLY AMPLIFIED WITH A STRONGLY TITLED RIDGE AXIS STRETCHING
NEWD FROM THE E CARIB ALONG 20N60W 32N48W. AN ASSOCIATED 1024 MB
SFC HIGH PRES SYSTEM IS LOCATED NEAR 30N41W CONTROLLING MUCH OF
THE SFC PATTERN AND PRODUCING MODERATE TRADES S OF 15N BETWEEN
30W-50W. THE UPPER FLOW THEN FOLDS INTO A BROAD EXTENSIVE TROUGH
WITH A ROUGH AXIS RUNNING FROM AN UPPER LOW NEAR THE MADEIRA
ISLANDS WELL SSW INTO THE DEEP TROPICS NEAR 4N40W. THIS UPPER
TROUGH HAS A SERIES OF WEAK SFC LOWS WHICH CONSIST OF A 1011 MB
NEAR 30N20W...A 1012 MB NEAR 35N16W AND ANOTHER 1012 MB NEAR
33N24W. BESIDES FOR SCATTERED SHOWERS WITHIN 120 NM IN THE NE
SEMICIRCLES OF THE LOWS AND A PATCH OF MAINLY HIGH CLOUDS FROM
15N-23N BETWEEN 26W-32W...FAIR TO MOSTLY CLEAR SKIES ARE THE
RULE.

$$
CANGIALOSI




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