[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 221746
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT JUL 22 2006

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...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...

TROPICAL WAVE THAT WAS PREVIOUSLY ALONG 32W/33W IS REPOSITIONED
ALONG 30W BASED ON VIS SATELLITE IMAGERY...EARLIER QUIKSCAT PASS
AND SURFACE DATA. A BROAD AREA OF LOW PRESSURE IS ALONG THE WAVE
AXIS NEAR 15N. THE LOW IS PRETTY WELL DEFINED ON VIS SATELLITE
PICTURES. WAVE/LOW ARE EMBEDDED WITH AN AREA OF DENSE AFRICAN
DUST...THUS NO ASSOCIATED DEEP CONVECTION.

TROPICAL WAVE IS ALONG 51W/52W S OF 18N MOVING W NEAR 15 KT.
WEAK...NARROW LOW LEVEL SIGNATURE CURVATURE IS OBSERVED ON
SATELLITE IMAGERY. WAVE IS ALSO EMBEDDED WITH AN AREA OF DENSE
AFRICAN DUST...THUS NO ASSOCIATED SHOWERS/CONVECTION.

WEAK TROPICAL WAVE IS ALONG 65W/66W S OF 20N MOVING W AROUND 15
KT. LIMITED LOW LEVEL MOISTURE IS ASSOCIATED WITH THE WAVE. THIS
SYSTEM IS CURRENTLY MOVING ACROSS PUERTO RICO. THE WAVE WILL
COMBINE WITH THE LOCAL ISLAND EFFECTS TO PRODUCE SCATTERED
SHOWERS AND ISOLATED TSTMS THIS AFTERNOON...MAINLY ACROSS THE
INTERIOR...WEST AND NW SECTORS OF THE ISLAND.

TROPICAL WAVE IS ALONG 94W S OF 21N MOVING W 15 KT. THIS WAVE IS
PRODUCING AN AREA OF SHOWERS AND THUNDERSTORMS OVER THE BAY OF
CAMPECHE AND THE EXTREME SOUTHWESTERN GULF OF MEXICO.
UPPER-LEVEL WINDS ARE CURRENTLY UNFAVORABLE FOR ANY RAPID
DEVELOPMENT OF THIS SYSTEM TO OCCUR. HOWEVER...CONDITIONS ARE
EXPECTED TO BECOME A LITTLE MORE CONDUCIVE FOR SOME GRADUAL
DEVELOPMENT AS THE SYSTEM MOVES SLOWLY NORTHWESTWARD OVER THE
NEXT COUPLE OF DAYS. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE
ALONG THE COAST OF MEXICO...ESPECIALLY OVER MOUNTAINOUS
TERRAIN...FROM VERACRUZ NORTHWARD TO TAMPICO. VERACRUZ REPORTED
2.6 INCHES OF RAIN THIS MORNING. THE WAVE IS ALSO GENERATING A
CLUSTER OF MODERATE/ISOLATED STRONG CONVECTION ON THE PACIFIC
SIDE.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N14W 10N28W 10N34W 5N51W. CLUSTERS
OF SCATTERED MODERATE/STRONG CONVECTION ARE ALONG THE ITCZ AXIS
BETWEEN 40W-42W AND BETWEEN 47W-49W. SCATTERED TO NUMEROUS
SHOWERS AND ISOLATED TSTMS ARE WITHIN 80/100NM ON EITHER SIDE OF
THE AXIS EAST OF 29W.

...DISCUSSION...
GULF OF MEXICO...
AN UPPER LOW IS IN THE E GULF NEAR 267N88W WITH AN UPPER TROUGH
EXTEND W JUST SOUTH OF BROWNSVILLE IN TEXAS. BROAD UPPER HIGH
OVER NORTH CAROLINA EXTENDS SW TO THE N GULF COAST. A SECOND
UPPER RIDGE COVERS SOUTH MEXICO...THE S GULF AND THE YUCATAN
PENINSULA. DIFFLUENCE COUPLED WITH THE TROPICAL WAVE IS
GENERATING THE CONVECTION OVER THE BAY OF CAMPECHE AND THE
EXTREME SW GULF OF MEXICO. A SURFACE TROUGH...REFLECTION OF THE
AFOREMENTIONED UPPER TROUGH EXTENDS FROM WESTERN FLORIDA NEAR
THE AREA NAPLES/FORT MYERS ALONG 24N-90W TO THE BAY OF CAMPECHE.
A WELL DEFINED BAND OF SHOWERS WITH EMBEDDED TSTMS IS ASSOCIATED
WITH THIS FEATURE. PART OF THIS CONVECTIVE ACTIVITY IS AFFECTING
SOUTH FLORIDA AND THE COASTAL WATERS...PARTICULARLY THE WEST
COAST.

CARIBBEAN SEA...
BROAD UPPER RIDGE OVER THE S GULF EXTENDS INTO THE W CARIBBEAN W
OF 85W WITH A WEAK UPPER RIDGE EXTENDING FROM THE CAYMAN ISLANDS
ACROSS CUBA NEAR 23N81W INTO THE W ATLC. AN INDUCED UPPER LOW IS
OVER THE CENTRAL CARIBBEAN LOCATED NEAR 14N74W. A SECOND UPPER
RIDGE COVERS THE SE CARIBBEAN AND THE LESSER ANTILLES. DRY AIR
AND SUBSIDENCE IS NOTED OVER THE BASIN EAST OF 84W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS OVER THE SW CARIBBEAN S
OF 11N AND OVER PANAMA AND COSTA RICA DUE TO THE PROXIMITY OF
THE EPAC ITCZ AXIS. STRONG TRADEWINDS CONTINUE ACROSS THE
CARIBBEAN S OF 18N WITH GALE FORCE WINDS EXPECTED SUNDAY NIGHT.

ATLANTIC OCEAN...
A WEAK UPPER RIDGE EXTENDS ACROSS CUBA AND THE BAHAMAS INTO THE
W ATLC ALONG 26N70W. AN UPPER LOW IS CENTERED N OF THE REGION
NEAR 35N70W WITH AN UPPER TROUGH EXTENDING SW TO NE FLORIDA NEAR
JACKSONVILLE. SCATTERED SHOWERS/THUNDERSTORMS ARE FROM 24N-30N W
OF 70W...INCLUDING THE NORTHERN BAHAMAS. AN UPPER LOW IS NORTH
OF PUERTO RICO NEAR 22N-65W. BROAD UPPER RIDGE COVERS THE
REMAINDER OF THE ATLC EXTENDING FROM AN UPPER HIGH LOCATED OVER
WEST AFRICA. AT THE SURFACE...BROAD RIDGE DOMINATES THE ATLC
GIVING THE AREA MODERATE ELY WINDS AND MOSTLY FAIR WEATHER.
ACCORDING TO THE 22/1500 UTC SAHARAN AIR LAYER FROM CIMSS...A
LARGE AREA OF DENSE AFRICAN DUST IS REACHING THE LESSER ANTILLES
WITH HAZY CONDITIONS. THE SAHARAN DUST OCCURS IN MOST CASES
BEHIND THE TROPICAL WAVES THAT MOVE WESTWARD ACROSS THE TROPICAL
ATLANTIC.

$$
GR





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