[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 072346
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT JUL 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...
A BROAD TROPICAL WAVE IS TILTED ALONG 15N32W TO 5N36W MOVING W
10-15 KT. THIS WAVE CONTINUES TO HAVE A LARGE ENVELOPE OF LOW TO
MID LEVEL CYCLONIC TURNING AND IS CAUSING A LARGE POLEWARD
PERTURBATION IN THE ITCZ. DESPITE ITS LARGE SIZE...SHOWER AND
TSTM ACTIVITY REMAINS MINIMAL AND DISORGANIZED.

A TROPICAL WAVE IS ALONG 60W/61W SOUTH OF 15N MOVING W 10-15 KT.
THIS WAVE IS PRODUCING A FEW SHOWERS AND TSTMS OVER THE WINDWARD
ISLANDS AND NE VENEZUELA. UPPER-LEVEL WINDS ARE NOT FAVORABLE
FOR DEVELOPMENT. THIS WAVE WILL MOVE ACROSS THE E CARIBBEAN
TOMORROW CROSSING MAINLY SOUTH OF PUERTO RICO.

A TROPICAL WAVE IN THE CARIBBEAN IS ALONG 76/77W MOVING W NEAR
15 KT. THIS WAVE...COUPLE WITH AN UPPER LOW LOCATED JUST SOUTH
OF HAITI IS GENERATING A FEW SHOWERS AND TSTMS OVER E CUBA...
HAITI AND JAMAICA AS WELL AS OVER NORTHERN COLOMBIA. THIS WAVE
WILL MOVE ACROSS CENTRAL AND THEN WESTERN CUBA TOMORROW.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N13W 5N22W 9N32W 7N40W 4N50W 7N57W.
SCATTERED MODERATE CONVECTION IS OFF THE AFRICAN COAST FROM
4N-10N E OF 18W. SIMILAR CONVECTION IS SEEN ALONG THE ITCZ AXIS
OVER THE GUIANAS. CLUSTERS OF MODERATE CONVECTION ARE NEAR 6N38W
AND 9N45W.

...DISCUSSION...
GULF OF MEXICO...
A SFC TROUGH REMAINS OVER CENTRAL FLORIDA AND THE SE GULF
GENERATING SCATTERED SHOWERS AND TSTMS MAINLY OVER THE FLORIDA
PENINSULA. A WEAK 1017 MB SFC HIGH ALSO REMAINS OVER THE
NORTHERN GULF WATERS. THIS IS KEEPING WINDS MOSTLY 15 KT OR
LESS. THIS HIGH WILL MERGE WITH AN ATLC RIDGE AXIS INTO SUN.
ALOFT...AN UPPER LOW IS SPINNING OVER SRN MEXICO NEAR 18N98W
WHILE AN UPPER HIGH LOCATED NEAR 28N87W DOMINATES MOST OF THE
GULF. DIFFLUENCE ASSOCIATED WITH THIS FEATURE IS ENHANCING THE
CONVECTIVE ACTIVITY OVER FLORIDA AND WESTERN CUBA. MOIST LOW
LEVEL SE/S FLOW RELATED TO THE UPPER LOW IS SUPPORTING A FEW
SHOWERS/TSTMS NOTED IN THE BAY OF CAMPECHE AND SOUTHERN MEXICO.
AN UPPER LOW SPINNING OVER THE SE U.S IS BRINGING BENEFICIAL
RAIN TO THE AREA. MOSAIC DOPPLER RADAR FROM THE SE US IS SHOWING
SCATTERED SHOWERS AND ISOLATED STRONG TSTMS FROM MISSISSIPPI TO
THE CAROLINAS.

CARIBBEAN SEA...
THE MOST ACTIVE WEATHER ACROSS THE BASIN IS FOUND OVER THE SW
CARIBBEAN AND SOUTHERN CENTRAL AMERICA DUE TO THE PRESENCE OF
THE EPAC ITCZ. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE
SEEN OVER THE AREA. SIMILAR CONVECTION IS OVER NORTHERN COLOMBIA
BEHIND THE TROPICAL WAVE LOCATED ALONG THE CENTRAL CARIBBEAN.
SEE ABOVE. ASIDE FROM THIS ACTIVITY...THE TROPICAL WAVE MOVING
THROUGH THE WINDWARD ISLANDS...AND TYPICAL TRADE WIND
SHOWERS...MODERATE TO STRONG SUBSIDENCE/DRY AIR ALOFT IS
PRODUCING MOSTLY FAIR WEATHER ELSEWHERE. MODERATE TO STRONG
TRADE WINDS ARE IN PLACE AND EXPECTED TO PERSIST INTO EARLY NEXT
WEEK.

ATLANTIC OCEAN...
THE SFC TROUGH OVER THE STATE OF FLORIDA IS ALSO GENERATING
SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE FAR WRN ATLC N OF
25N WEST OF 75W. UPPER DIFFLUENCE AROUND AN UPPER RIDGE AXIS
EXTENDING E INTO THE REGION FROM THE GULF IS SUPPORTING THIS
ACTIVITY. THE REMAINDER OF THE ATLC SFC PATTERN IS DOMINATED BY
A LARGE SFC RIDGE AXIS ANCHORED BY A 1029 MB HIGH JUST N OF THE
AZORES. THIS IS PRODUCING MOSTLY FAIR WEATHER WITH ONLY PATCHES
OF LOW/MID CLOUDS AND LIGHT TO MODERATE WINDS N OF 15N E OF 75W.
THE SFC TROUGHING OFF OF FLORIDA AND THE SOUTHEAST U.S. COAST IS
EXPECTED TO LIFT NE THROUGH SUN WHILE THE RIDGE AXIS BUILDS W
THROUGH THE GULF. ELSEWHERE ALOFT...BOTH THE FAR W AND E
PORTIONS OF THE DISCUSSION AREA ARE DOMINATED BY UPPER RIDGES.
SEVERAL SMALLER SCALE UPPER FEATURES NOTED OVER THE CENTRAL ATLC
BUT ARE NOT GENERATING MUCH WEATHER. A WEAK COLD FRONT IS
CLIPPING THE FORECAST AREA NEAR 31N40W.

$$
GR



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