[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 072344
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED NOV 07 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
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
2315 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 53W S OF 11N MOVING W 10-15 KT. THE
UW-CIMSS TPW PRODUCT STILL SHOWS THE PRESENCE OF THIS SYSTEM
WITH A BULGE OF MOISTURE. THE WAVE COUPLE WITH THE ITCZ AXIS IS
PRODUCING SOME SHOWER ACTIVITY OVER FRENCH GUIANA AND SURINAME.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 9N13W 4N30W 5N51W. SCATTERED
MODERATE CONVECTION IS WITHIN 200 NM EITHER SIDE OF THE AXIS
BETWEEN 25W-42W.

DISCUSSION...

GULF OF MEXICO...
THE LAST FEW VISIBLE SATELLITE IMAGERY CLEARLY SHOWS A COLD
FRONT PUSHING S THROUGH THE GULF...WITH A NARROW BAND OF LOW AND
MID CLOUDS WITH POSSIBLE LIGHT SHOWERS STRETCHING ACROSS THE
GULF BETWEEN SOUTH FLORIDA/FLORIDA KEYS AND BROWNSVILLE TEXAS.
WINDS ARE PICKING UP TO 20 KT BEHIND THE FRONT. AN EARLIER
QUIKSCAT PASS CONFIRMED THESE WINDS. MOSTLY 10-15 KT NE WINDS
ARE ELSEWHERE TRANSPORTING PATCHES OF LOW LEVEL CLOUDS WITH
MAINLY LIGHT SHOWERS ACROSS THE BAY OF CAMPECHE INTO THE STATES
OF VERACRUZ AND TABASCO IN MEXICO. THE FRONT WILL RAPIDLY MOVE S
AND WEAKEN FROM THE STRAITS OF FLORIDA TO NE MEXICO OVERNIGHT.
STRONG HIGH PRES WILL BUILD ACROSS THE AREA IN THE WAKE OF THE
FRONT BRINGING A VERY DRY AND COOL AIR MASS. IN THE UPPER
LEVELS...A LONG WAVE TROUGH OVER THE EASTERN SEABOARD SUPPORTS
THE AFOREMENTIONED COLD FRONT. A JET STREAM BRANCH...WITH CORE
WINDS OF 70-90 KT ROUNDS THE BASE OF THIS TROUGH CROSSING SE
LOUISIANA...FLORIDA AND THE NW BAHAMAS INTO THE W ATLC.

CARIBBEAN SEA...
A SFC TROUGH...REMNANT OF A QUASI-STATIONARY FRONT REMAINS OVER
THE NW CARIBBEAN BETWEEN THE WINDWARD PASSAGE AND THE NE TIP OF
HONDURAS. THIS IS GENERATING SCATTERED MODERATE CONVECTION NEAR
THE COAST OF HONDURAS FROM 15N-18N BETWEEN 79W-84W. ISOLATED TO
SCATTERED SHOWERS ARE ALSO OVER THE SW CARIBBEAN WITHIN 150 NM
OF THE COAST OF NICARAGUA...COSTA RICA...AND PANAMA. MODERATE TO
FRESH NE WINDS CONTINUE TO BLOW OVER THE NW CARIBBEAN BEHIND THE
TROUGH...AND ARE EXPECTED TO SLOWLY RELAX THROUGH THE END OF THE
WEEK AS HIGH PRES BUILDS OVER THE NE GULF. CLUSTERS OF MODERATE
TO ISOLATED STRONG CONVECTION HAVE DEVELOPED OVER WESTERN
VENEZUELA...INCLUDING THE LAKE MARACAIBO AND N COLOMBIA. SWLY
UPPER-LEVEL FLOW IS HELPING TO INDUCE THIS CONVECTIVE ACTIVITY
THAT APPEARS TO BE ASSOCIATED WITH THE COLOMBIAN OR PANAMANIAN
LOW...ANALYZED 1007 MB NEAR 9N77W. THE CENTRAL AND ERN CARIBBEAN
ARE DOMINATED BY LIGHT TO MODERATE TRADES AND MOSTLY FAIR
WEATHER ASIDE FROM A FEW SHALLOW SHOWERS. ALOFT...A LONG WAVE
TROUGH IS OVER THE EASTERN U.S. WITH THE BASE OF THE TROUGH
REACHING CENTRAL CUBA. A BROAD UPPER RIDGE DOMINATES MOST OF THE
BASIN...PARTICULARLY THE EASTERN PORTION.

ATLANTIC OCEAN...
AS OF 07/2100 UTC A COLD FRONT ENTERS THE FORECAST AREA NEAR
31N72W THEN CONTINUES SW THROUGH THE STRAITS OF FLORIDA INTO THE
GULF OF MEXICO. THE FRONT IS MOSTLY CHARACTERIZED BY A THIN LINE
OF LOW CLOUDS AND LIGHT SHOWERS. THE MOSAIC DOPPLER RADAR FROM
THE SE U.S. SHOWS A FEW SHOWERS BETWEEN SE FLORIDA AND THE NW
BAHAMAS. NLY WINDS OF 20-25 KT ARE INCREASING BEHIND THE FRONT.
ANOTHER FRONT ENTERS THE AREA AS STATIONARY NEAR 31N56W SW TO
25N70W...THEN CONTINUES AS A TROUGH TO THE WINDWARD PASSAGE. AS
PREDICTED BY THE GFS MODEL...A WEAK AREA OF LOW PRES HAS
DEVELOPED ALONG THIS BOUNDARY NEAR 25N70W. THIS FRONTAL SYSTEM
IS GETTING SUPPORT BY AN UPPER TROUGH CURRENTLY MOVING THROUGH
THE BAHAMAS. THESE SFC FEATURES PAIRED WITH UPPER SWLY WINDS
AHEAD OF THE UPPER TROUGH ARE GENERATING WIDESPREAD CLOUDINESS
WITH EMBEDDED SHOWERS N OF 25N BETWEEN 55W-65W. THE UPPER LOW
THAT WAS NEAR THE LESSER ANTILLES DURING THE PREVIOUS DAYS HAS
MOVED EWD AND NOW IS NEAR 17N49W. THIS SYSTEM IS PRODUCING
MOSTLY HIGH CLOUDINESS WITH POSSIBLE SHOWERS FROM 8N-18N BETWEEN
38W-49W. A 1006 MB NON-TROPICAL LOW PRESSURE AREA IS CENTERED
ABOUT 445 NM SOUTH-SOUTHWEST OF THE AZORES...MOVING TO THE
EAST-NORTHEAST AT ABOUT 10 TO 15 MPH. THE ASSOCIATED SHOWER
ACTIVITY REMAINS DISORGANIZED...AND UPPER-LEVEL WINDS ARE NOT
FAVORABLE FOR SIGNIFICANT DEVELOPMENT. A TRAILING TROUGH IS
ALONG 30N27W 20N36W 14N45W. SCATTERED SHOWERS ARE ASSOCIATED
WITH THIS TROUGH MAINLY N OF 23N E OF 30W. MODERATE SFC RIDGING
DOMINATES THE REMAINDER OF THE E ATLC AREA. ALOFT...A
TROUGH/RIDGE/TROUGH/RIDGE PATTERN DOMINATES THE DISCUSSION AREA.

$$
GR




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