[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 070004
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI APR 06 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2330 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N12W 3N20W 1N30W 2N40W AND INTO
SOUTH AMERICA NEAR EQ50W. CLUSTER OF MODERATE TO STRONG
CONVECTION IS WITHIN 120NM N AND 30NM S OF THE AXIS BETWEEN
16W-19W. ISOLATED MODERATE CONVECTION IS FROM 3S-3N BETWEEN
23W-30W.

...DISCUSSION...

GULF OF MEXICO...
CLEAR SKIES AND DRY AIR DOMINATE THE GULF WATERS N OF 26N BEHIND
THE COLD FRONT THAT NOW EXTENDS THROUGH THE NW CARIBBEAN.
SCATTERED TO BROKEN STRATOCUMULUS CLOUDS SEEN S OF 26N IN WAKE
OF THE FRONT. A LARGE AREA OF CANADIAN SFC HIGH PRES IS BUILDING
INTO THE GULF FROM THE N...PRODUCING MODERATE NW TO N WINDS E OF
90W THAT VEER MORE NE IN THE WRN GULF. A CHILLY EVENING IS
ANTICIPATED ACROSS FLORIDA TONIGHT WITH WIDESPREAD CLEAR SKIES
AND COLD ADVECTION PATTERN. A REINFORCING FRONT WILL ALLOW N TO
NE WINDS TO INCREASE AGAIN IN THE NRN GULF DURING SAT.
ALOFT...UPPER FLOW IS WIDELY WNW TO W AHEAD OF A RIDGE EXTENDING
N THROUGH MEX AND TX...AND AT THE BASE OF A LARGE POLAR TROUGH
EXTENDING S THROUGH THE ERN U.S. THIS IS USHERING VERY DRY MID
TO UPPER AIR ESE THROUGH THE NE GULF AND INTO FLORIDA. UPPER
MOISTURE FROM THE EPAC IS SPREADING INTO THE FAR WRN GULF N OF
22N.

CARIBBEAN SEA...
AS OF 06/2100 UTC A COLD FRONT EXTENDS THROUGH THE NW CARIB
ALONG 22N80W TO THE ERN YUCATAN NEAR 19N88W. THIS HAS BEEN
RELOCATED NW FROM PREVIOUS MAPS...AS SUSPECT THE CONFLUENCE/WIND
SHIFT NOTED FURTHER SE IS MORE ASSOCIATED WITH PREFRONTAL
TROUGHINESS WHILE THE NEW PLACEMENT SEEMS MORE ASSOCIATED WITH
THE THERMAL AND MOISTURE DEMARCATION. ASSOCIATED ISOLATED SHOWER
ACTIVITY NOTED BETWEEN HONDURAS AND CUBA. THE SW PORTION OF AN
ATLC SFC RIDGE DOMINATES THE CENTRAL AND WRN CARIB. THE WEAKER
GRADIENT AHEAD OF THE FRONT HAS LED TO LIGHTER THAN NORMAL E TO
SE WINDS ACROSS THE AREA E OF 80W. FRONT IS EXPECTED TO STALL
BETWEEN E CUBA AND HONDURAS THROUGH LATE SAT AND THEN DISSIPATE
INTO SUN. QUICK SURGE OF MODERATE TO FRESH NLY WINDS EXPECTED IN
THE NW CARIB TONIGHT AND SAT BEFORE RELAXING INTO SUN. EXTENSIVE
UPPER MOISTURE IS BEING ADVECTING NE THROUGH MUCH OF THE CARIB
WITH UPPER SW FLOW AROUND RIDGING. THE EXCEPTION IS THE FAR NW
PORTION WHERE VERY DRY MID TO UPPER AIR IS PRESENT AT THE SRN
PERIPHERY OF THE UPPER TROUGHING EXTENDING S THROUGH THE ERN
U.S. TO CENTRAL CUBA.

ATLANTIC OCEAN...
CLASSIC BAROCLINIC LEAF PATTERN IS OVER THE WRN ATLC. A 1006 MB
LOW NEAR 30N72W HAS A TRAILING COLD FRONT THAT EXTENDS SW
THROUGH THE CENTRAL BAHAMAS. THE LOW WILL PUSH NE OF THE AREA
AND EVENTUALLY GET ABSORBED INTO A STRONGER CYCLONE TO DEVELOP
OFF THE MID ATLC U.S. COAST DURING SAT. BROKEN TO OVERCAST
MULTILAYERED CLOUDS WITH SCATTERED TO NUMEROUS SHOWERS WITH THIS
PATTERN ARE OVER THE ATLC AREA BETWEEN 65W-76W. ISOLATED TSTMS
ALSO ANTICIPATED WHERE THE COLDEST CLOUD TOPS NOTED FROM 26N-32N
BETWEEN 66W-71W. ALL THIS ACTIVITY IS BEING SUPPORTED BY THE
UPPER DIFFLUENT ZONE AHEAD OF THE MID TO UPPER TROUGH EXTENDING
S THROUGH THE ERN U.S. AND THE FAR WRN ATLC. LARGE SCALE UPPER
RIDGING PUSHING INTO THE CENTRAL ATLC IS SPREADING ABUNDANT
UPPER MOISTURE EWD OUT TO 50W. SFC HIGH PRES IS ALSO OVER THE
CENTRAL ATLC WITH A 1022MB CENTER NEAR 29N49W. THE E ATLC IS
DOMINATED BY UPPER TROUGHING WITH AXIS EXTENDING S ALONG 34W.
ASSOCIATED WEAK COLD FRONT ENTERS THE AREA AT 32N27W AND
CONTINUES SW TO 24N40W. THIS FRONT EXPECTED TO DISSIPATE THROUGH
SAT AS HIGH PRES TAKES OVER THE CENTRAL AND ERN ATLC.

$$
WILLIS


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