[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 111756
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN MAR 11 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1730 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N11W 4N25W EQ43W AND INTO NE
BRAZIL NEAR 2S47W. SCATTERED CLUSTERS OF MODERATE CONVECTION ARE
WITHIN 120 NM EITHER SIDE OF THE AXIS E OF 31W. SIMILAR ACTIVITY
IS FROM 4S-EQ BETWEEN 34W-45W...WHICH INCLUDES THE ACTIVITY NEAR
THE NE COAST OF BRAZIL. A REGION OF SCATTERED MODERATE IS ALSO
NORTH OF THE AXIS FROM 3N-5N BETWEEN 44W-53W.

...DISCUSSION...

GULF OF MEXICO...
WEAK SFC HIGH PRES RIDGING CONTINUES TO DOMINATE THE GULF FROM A
1025 MB CENTER OVER SW GEORGIA. LIGHT TO MODERATE ELY WINDS E OF
90W BEND MORE SELY IN THE WRN GULF. SIMILAR TO SLIGHTLY STRONGER
E/SE WINDS EXPECTED THROUGH EARLY WEEK AS HIGH PRESSURE N OF THE
AREA PUSHES E AND OFFSHORE THE MID ATLANTIC STATES. IN THE UPPER
LEVELS...STRONG NEARLY ZONAL FLOW DOMINATES MUCH OF THE BASIN
BETWEEN RIDGING EXTENDING N FROM THE SW CARIBBEAN AND A COUPLE
OF SHORTWAVE TROUGHS PUSHING THROUGH THE CONUS AND OFF THE E
COAST. THESE STIFF WINDS ARE ADVECTING ABUNDANT UPPER LEVEL
MOISTURE/HIGH CLOUDS FROM THE EPAC ACROSS CENTRAL MEXICO INTO
THE GULF EXCEPT FOR THE FAR NE PORTION WHERE DRY AIR EXISTS.
INCREASING DEEP LAYER MOISTURE WITH POSSIBLE SHOWERS EXPECTED IN
THE WRN GULF EARLY TO MID WEEK...AHEAD OF THE UPPER LOW TO
REMAIN QUASI-STATIONARY OVER WRN TEXAS AND RETURN FLOW AROUND
THE SFC HIGH NE OF THE AREA.

CARIBBEAN...
A CLUSTER OF MODERATE CONVECTION FORMED JUST OFFSHORE SRN
NICARAGUA AND COSTA RICA THIS MORNING...BUT THIS AREA HAS BEEN
DIMINISHING IN BOTH COVERAGE AND INTENSITY OVER THE LAST COUPLE
HOURS. THIS IS ONE OF THE ONLY NOTABLE CONVECTIVE CLUSTERS
NOTICED IN THE CARIBBEAN OVER THE PAST SEVERAL WEEKS. ELSEWHERE
THE WEATHER REMAINS DOMINATED BY DRY STABLE AIR ALOFT THAT IS
ROTATING AROUND UPPER RIDGING OVER THE BASIN. OVERALL FAIR
WEATHER AND TYPICAL ISOLATED SHOWERS DRIVEN BY MODERATE TRADES
ARE THE THEME ACROSS THE SEA TODAY. MORE OF THE SAME...TRANQUIL
WEATHER AND MODERATE TO FRESH TRADES...IS THE FORECAST FOR THE
NEXT COUPLE OF DAYS.

WESTERN ATLANTIC...
THE MESSY...COMPLEX WEATHER SITUATION OVER THE WRN ATLC THE LAST
FEW DAYS HAS EVOLVED AND SORTED ITSELF OUT QUITE A BIT. LIGHT TO
MODERATE NE WINDS ARE FOUND OVER MUCH OF THE AREA W OF 68W OR
BEHIND THE COLD FRONT THAT ENTERS THE AREA NEAR 32N65W AND
CONTINUES SSW TO 26N68W...WHERE IT LOSES MUCH OF ITS THERMAL
CONTRAST AND CONTINUES SW AS A TROUGH TO NEAR 22N72W. THE FRONT
IS ASSOCIATED WITH THE 1009 MB SFC LOW JUST N OF THE AREA NEAR
33N65W. MOST OF THE CONVECTION IN THE AREA IS ASSOCIATED WITH
THE PREFRONTAL TROUGH ANALYZED ALONG 29N63W 23N66W TO THE COAST
OF HISPANIOLA NEAR 19N72W. THE TROUGH IS MARKED BY CONFLUENT SW
INTO SE FLOW...AND BROKEN TO OVERCAST DEEP LAYER CLOUDINESS WITH
EMBEDDED SHOWERS/TSTMS WITHIN 150 NM OF THE AXIS. THE CONVECTION
IS ALSO SUPPORTED BY A CLEAR UPPER DIFFLUENT ZONE AHEAD OF THE
DOMINATING SHORTWAVE UPPER TROUGH MOVING THROUGH THE AREA.
LOOKING AHEAD...THE LOW PRES SYSTEM IS EXPECTED TO CONTINUE
DEEPENING AS IT TRACKS RATHER QUICKLY TO THE N. HOWEVER...THE
ASSOCIATED TRAILING FRONTAL TROUGH WILL REMAIN IN THE REGION FOR
THE NEXT COUPLE OF DAYS. THE MODERATE ELY SWELL FROM THIS STORM
THAT IS CURRENTLY AFFECTING EXPOSED FLORIDA BEACHES NORTH OF THE
BAHAMA SHADOW ZONE WILL SUBSIDE SLOWLY THROUGH MIDWEEK.

EASTERN ATLANTIC...
STRONG HIGH PRESSURE RIDGING CONTINUES TO DOMINATE THE SFC
PATTERN ACROSS MUCH OF THE CENTRAL AND EASTERN ATLC. THIS HIGH
IS PRODUCING MODERATE TO FRESH TRADE WINDS AND FAIR WEATHER
ACROSS A GOOD PORTION OF THE AREA. IN THE MID AND UPPER
LEVELS...STRONG RIDGING ALSO DOMINATES WITH A HIGH CENTER NEAR
21N31W. DRY AND STABLE AIR ALOFT RESULTING IN STRONG SUBSIDENCE
IS AIDING IN THE WIDESPREAD FAIR WEATHER. THE TRADE WINDS ARE
SET TO PICK UP AGAIN FROM W TO E STARTING TODAY INTO NEXT WEEK
AS STRONG HIGH PRES REBUILDS E ACROSS THE ATLC OCEAN. UPPER
RIDGING WILL ALSO REMAIN IN CONTROL SUPPORTING THE CONTINUATION
OF FAIR WEATHER.

$$
WILLIS




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