[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 062353
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI JUL 06 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...

A VERY BROAD TROPICAL WAVE IS TITLED ALONG FROM 20N27W TO 5N30W
MOVING W 10-15 KT. THIS WAVE HAS A LARGE ENVELOPE OF LOW-LEVEL
TURNING AND IS CAUSING QUITE A PERTURBATION IN THE ITCZ.
SCATTERED SHOWERS ARE ON THE SOUTHERN END OF THE WAVE MAINLY
WITHIN THE ITCZ.

A TROPICAL WAVE IS ALONG 55W MOVING W AT 10 TO 15 KT. A 1014 MB
LOW REMAINS ALONG THE WAVE AXIS NEAR 11N. LATEST VISIBLE IMAGES
SHOWS A SWIRL OF MAINLY LOW CLOUDS WITH SOME CONVECTIVE ACTIVITY
ON THE SOUTH SIDE OF THE LOW...THAT IS FORECAST TO CONTINUE
MOVING WWD AS AN OPEN WAVE REACHING THE WINDWARD ISLANDS
TOMORROW.

A TROPICAL IS ALONG 70W MOVING W NEAR 15 KT. THE WAVE COUPLE
WITH THE AFTERNOON HEATING IS ENHANCING SOME SHOWER ACTIVITY
OVER HISPANIOLA AND WESTERN VENEZUELA NEAR LAKE MARACAIBO. WAVE
WILL MOVE ACROSS E CUBA AND JAMAICA SAT.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 5N10W 9N20W 11N32W 5N45W 7N52W.
CLUSTERS OF SCATTERED MODERATE CONVECTION ARE MOVING OUT OF THE
AFRICAN COAST ALONG 10N. SIMILAR CONVECTION IS FOUND WITHIN
60-90 NM N OF AXIS BETWEEN 36W-40W. SCATTERED SHOWERS ARE FROM
4N-7N BETWEEN 14W-17W.

...DISCUSSION...
GULF OF MEXICO...
WEAK SFC TROUGH REMAINS OVER CENTRAL FLORIDA AND THE E GULF
EXTENDING FROM A SFC LOW LOCATED NEAR 30N79W AT 21Z. ONCE
AGAIN...SHOWERS AND TSTMS HAVE FLARED UP ACROSS MOST OF CENTRAL
AND SOUTH FLORIDA. THE LOW IS FORECAST TO MOVE NORTH OF AREA
TONIGHT AND WILL DISSIPATE BY LATE SATURDAY. SCATTERED SHOWERS
ARE ALSO SEEN ALONG THE SFC TROUGH OVER THE E GULF. A DIFFLUENT
PATTERN ALOFT ASSOCIATED WITH AN UPPER HIGH LOCATED OVER THE
NORTHERN GULF WATERS IS SUPPORTING THIS CONVECTIVE ACTIVITY.
NUMEROUS SHOWERS AND TSTMS ARE OVER EXTREME E TEXAS...LOUISIANA
AND THEIR COASTAL WATERS RELATED TO A SFC LOW/TROUGH OVER THE
AREA. FURTHER S...AN UPPER LOW IS SPINNING OVER THE ISTHMUS OF
TEHAUNTEPEC DRAWING TROPICAL MOISTURE FROM THE EPAC INTO THE
YUCATAN PENINSULA AND THE BAY OF CAMPECHE. AS A RESULT...AN
AREA OF MODERATE CONVECTION HAS DEVELOPED OVER THE NORTHERN
YUCATAN PENINSULA. THE SFC FLOW IS MAINLY GOVERNED BY A 1020 MB
HIGH CENTERED NEAR 27N89W. LIGHT TO MODERATE WINDS ARE BLOWING
ACROSS THE GULF. WEAK RIDGING IS EXPECTED TO REMAIN IN CONTROL
THIS WEEKEND.

CARIBBEAN SEA...
DRY AIR ALOFT...RESULTING IN MODERATE TO STRONG SUBSIDENCE
DOMINATES MOST OF THE BASIN. AN UPPER LOW OVER THE WINDWARD
PASSAGE IS HELPING TO DEVELOP SCATTERED SHOWERS AND ISOLATED
TSTMS OVER HISPANIOLA WHERE THERE IS A TROPICAL WAVE. SEE ABOVE.
SCATTERED MODERATE CONVECTION ARE ALSO SEEN OVER CENTRAL AMERICA
AND THE SW CARIBBEAN DUE TO THE UPPER LOW PREVIOUSLY MENTIONED
OVER THE ISTHMUS OF TEHUANTEPEC AND THE CLOSE PROXIMITY OF THE
EPAC ITCZ. TYPICAL TRADE WINDS SHOWERS ARE OBSERVED ACROSS THE
BASIN. SCATTERED SHOWERS AND ISOLATED TSTMS ARE AFFECTING
WESTERN CUBA. THE PRES GRADIENT BETWEEN THE ATLC RIDGE AND THE
COLOMBIAN LOW IS PRODUCING STRONG TRADE WINDS OF 20 TO 30 KT
ACROSS THE SOUTH-CENTRAL CARIBBEAN SEA. THESE WINDS ARE EXPECTED
TO PERSIST DURING THE UPCOMING WEEKEND.

ATLANTIC OCEAN...
AN ELONGATED AND WEAK LOW PRESSURE AREA LOCATED NEAR 30N79W IS
PRODUCING DISORGANIZED SHOWERS AND THUNDERSTORMS EXTENDING FROM
THE SOUTHERN FLORIDA PENINSULA NORTHEASTWARD INTO THE ATLANTIC
FOR SEVERAL HUNDRED MILES. UPPER-LEVEL WINDS ARE NOT FAVORABLE
FOR DEVELOPMENT. A TROUGH EXTENDS FROM THIS LOW ACROSS CENTRAL
FLORIDA INTO THE GULF OF MEXICO. THE REMAINDER OF THE FORECAST
AREA IS UNDER THE INFLUENCE OF THE ATLC RIDGE GIVING THE AREA
MOSTLY FAIR WEATHER AND LIGHT TO MODERATE TRADE WINDS. MODERATE
TO STRONG NLY WINDS ARE NEAR THE AFRICAN COAST DUE TO THE
TIGHTENING PRES GRADIENT BETWEEN THE AZORES HIGH AND INVERTED
TROUGHING OVER THE CONTINENT. ALOFT...DRY AIR COVERS MOST OF THE
AREA. THERE IS SOME TROUGHING IN THE CENTRAL/E ATLC WITH A
COUPLE OF UPPER LOWS...BUT OVERALL THESE UPPER FEATURES ARE NOT
PRODUCING MUCH WEATHER. ONLY PATCHES OF LOW/MID CLOUDS ARE SEEN
ACROSS THE AREA...PARTICULARLY E OF 40W.

$$
GR





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