[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 011805
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE MAY 01 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
1745 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N12W 3N20W 1N30W AND CROSSING THE
EQUATOR NEAR 40W. ISOLATED CLUSTERS OF MODERATE TO STRONG
CONVECTION HAVE BEEN POPPING UP S OF THE AXIS/OFFSHORE LIBERIA
OVER THE LAST FEW HOURS FROM 1N-7N E OF 15W. THE LARGEST
CONCENTRATION OF CONVECTION NEAR THE ITCZ IS THE NUMEROUS
MODERATE FROM 2S-5N BETWEEN 25W-35W. THIS AREA HAS BEEN SHOWING
SOME TROPICAL WAVE-LIKE CHARACTERISTICS OVER THE LAST DAY OR
SO...AND MAY BE ADDED AS EITHER A TROUGH OR A WAVE TO THE 1800
UTC MAP.

...DISCUSSION...

GULF OF MEXICO...
THE SW PORTION OF AN ATLC SFC RIDGE AXIS EXTENDS INTO THE GULF
THIS AFTERNOON WHICH IS PRODUCING LIGHT TO MODERATE RETURN FLOW
ACROSS THE AREA. SKIES ARE MOSTLY CLEAR WITH JUST A FEW FAIR
WEATHER CUMULUS CLOUDS NOTED. MODERATE RETURN FLOW WILL PERSIST
IN THE WRN AND CENTRAL GULF OVER THE NEXT COUPLE OF DAYS AROUND
RIDGING...WITH LIGHTER WINDS ANTICIPATED IN THE ERN WATERS.
UPPER FLOW OVER THE GULF IS MOSTLY OF A CYCLONIC NATURE AROUND
TROUGHING EXTENDING S FROM THE UPPER LOW OVER OKLAHOMA. THIS IS
TRANSPORTING SOME UPPER MOISTURE EWD BETWEEN LOUISIANA AND THE
YUCATAN PENINSULA. OTHERWISE...FAIRLY DRY/STABLE AIR IS NOTED IN
WV IMAGERY ESPECIALLY IN THE FAR NE PORTION.

CARIBBEAN SEA...
MODERATE TO FRESH TRADE FLOW WITH TYPICAL LOW LEVEL MOISTURE
PATCHES DOMINATE MUCH OF THE BASIN THIS AFTERNOON. ADDITIONAL
LOW LEVEL CONFLUENCE AND UPPER DIFFLUENCE ARE ALLOWING THESE
SHOWERS TO GET A LITTLE DEEPER IN THE NW CARIB BETWEEN HONDURAS
AND CUBA. THE LOW LEVEL CLOUD MOTIONS IN THE NE PORTION...MAINLY
N OF 16N AND E OF 70W...ARE MORE FROM THE SE ON THE SW PORTION
OF THE AZORES HIGH. THIS HAS SUPPLIED GOOD LOW LEVEL
MOISTURE TO THE LEEWARD ISLANDS THROUGH HISPANIOLA...WHICH HAS
COMBINED WITH DIURNAL HEATING FOR CONTINUED SUPPORT FOR THE
SHOWER ACTIVITY NOTED FROM THE SAN JUAN RADAR. SWLY UPPER FLOW
DOMINATES W OF 75W AHEAD OF THE UPPER TROUGHING EXTENDING S
THROUGH THE GULF. FLOW IS MORE ZONAL E OF 75W N OF RIDGING FROM
SOUTH AMERICA. SIMILAR TRADE WIND REGIME EXPECTED OVER THE NEXT
COUPLE OF DAYS.

ATLANTIC...
WEAK HIGH PRESSURE DOMINATES THE WESTERN ATLC WITH A COUPLE OF
EXCEPTIONS THANKS TO OUR OLD FRONTAL BOUNDARY. A REMNANT TROUGH
EXTENDS THROUGH ELEUTHERA AND ADJACENT WATERS ALONG 28N75W
24N77W. THIS IS PRODUCING SCATTERED SHOWERS MAINLY NE OF THE
BAHAMAS FROM 25N-28N BETWEEN 73W-78W. THIS TROUGH HAS BROKEN OFF
FROM THE MAIN FRONTAL TROUGH THAT ENTERS THE AREA NEAR 31N55W
AND CONTINUES SW TO 27N66W. ASSOCIATED SCATTERED SHOWERS WITH
ISOLATED TSTMS ARE N OF 26N BETWEEN 51W-63W. THIS ACTIVITY ALSO
BEING SUPPORTED BY UPPER DIFFLUENCE BETWEEN UPPER TROUGHING
EXTENDING S FROM THE CANADIAN MARITIMES AND THE UPPER HIGH NEAR
33N35W. OTHERWISE THE REMAINDER OF THE ATLC DISCUSSION AREA IS
DOMINATED BY THE SRN PERIPHERY OF A STATIONARY 1028 MB SFC HIGH
S OF THE AZORES NEAR 34N31W. THIS IS PRODUCING WIDESPREAD FAIR
WEATHER AND MODERATE TO FRESH TRADES E OF 50W. OVERALL LARGE
SCALE SFC RIDGING WILL DOMINATE THE AREA OVER THE NEXT COUPLE OF
DAYS...THOUGH MODEL GUIDANCE SUGGESTS TROUGHING WILL LINGER NEAR
THE BAHAMAS SO ASSOCIATED SHOWER ACTIVITY SHOULD PERSIST.

$$
WILLIS




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