[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 222311
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2300 UTC.

...TROPICAL WAVES...

AN EASTERN ATLANTIC TROPICAL WAVE IS ALONG 33W SOUTH OF 20N
MOVING WEST 10-15 KT. A 1013 MB LOW IS ALONG THE WAVE NEAR 15N.
THIS AREA OF LOW PRES IS CLEARLY DEFINED ON SATELLITE IMAGERY
AND IN THE SURROUNDING SHIPS/BUOYS. DESPITE THE WELL DEFINED
STRUCTURE OF THE WAVE AND LOW...A WIDESPREAD AREA OF SAHARAN
DUST IS SUPPRESSING ANY SIGNIFICANT SHOWER ACTIVITY. ONLY
SCATTERED SHOWERS ARE SURROUNDING THESE FEATURES EMBEDDED IN THE
ITCZ. THIS WAVE WILL LIKELY INCREASE IN FORWARD SPEED OVER THE
NEXT COUPLE OF DAYS AS IT TRACKS UNDER THE STRONG LOW-LEVEL
RIDGE.

A TROPICAL WAVE IS ALONG 53W S OF 17N MOVING WEST NEAR 15 KT.
THIS WAVE HAS LOST MUCH OF ITS IDENTITY OVER THE PAST FEW
DAYS...WITH VERY LITTLE SIGNATURE NOTED ON SATELLITE IMAGERY.

A TROPICAL WAVE IS IN THE CARIBBEAN ALONG 67W S OF 20N MOVING
WEST NEAR 15 KT. SIMILARLY TO THE WAVE TO ITS EAST...THIS WAVE
IS ALSO VERY WEAK WITH ONLY A HINT OF SOME WAVE STRUCTURE.
LIMITED MOISTURE IS ASSOCIATED WITH THE WAVE...BUT IT MAY BE
INFLUENCING...ALONG WITH LOCAL EFFECTS...SCATTERED SHOWERS AND
TSTMS ACROSS THE VIRGIN ISLANDS...PUERTO RICO AND HISPANIOLA.

A TROPICAL WAVE IS ALONG 95W S OF 21N MOVING W 10-15 KT OVER THE
PAST 24 HOURS. THIS WAVE IN PART IS GENERATING A WIDE AREA OF
SHOWERS AND THUNDERSTORMS ACROSS S MEXICO AND THE BAY OF
CAMPECHE...NAMELY S OF 24N BETWEEN 88W-98W. CURRENTLY THIS AREA
APPEARS UNFAVORABLE FOR ANY SIGNIFICANT DEVELOPMENT. THIS WAVE
HAS BEGUN TO SLOW IN FORWARD SPEED AS THE STEERING CURRENTS ARE
RATHER WEAK.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 13N14W 15N28W 9N41W 8N52W TO INLAND
OVER SOUTH AMERICA NEAR 7N58W. SCATTERED SHOWERS AND ISOLATED
TSTMS ARE WITHIN 240 NM EITHER SIDE OF THE AXIS E OF OF 39W
ENHANCED BY THE TROPICAL WAVE AND SFC LOW ALONG 33W. SMALL
CLUSTERS OF SCATTERED SHOWERS AND TSTMS ARE WITHIN 180 NM TO
THE SOUTH OF THE AXIS BETWEEN 42W-52W.

...DISCUSSION...
GULF OF MEXICO...
THERE ARE A FEW AREAS OF UNSETTLED WEATHER IN THE GULF OF MEXICO
THIS EVENING. THE MAIN FEATURE IS AN UPPER LEVEL LOW IN THE
CENTRAL GULF CENTERED NEAR 26N88W. THIS UPPER LOW HAS AN
ILL-DEFINED SFC REFLECTION AS A TROUGH ALONG 26N FROM SOUTH
FLORIDA TO 86W. A NARROW UPPER HIGH IS CENTERED TO THE SOUTHEAST
OF THE UPPER LOW BETWEEN CUBA AND THE SW BAHAMAS. THIS UPPER
LEVEL PATTERN AND WEAK SFC BOUNDARY IS PRODUCING A CONSIDERABLE
AMOUNT OF MOISTURE ACROSS THE EASTERN GULF E OF 87W S OF 28N.
UPPER DIFFLUENCE APPEARS TO BE THE STRONGEST ACROSS SOUTH
FLORIDA AND THE BAHAMAS WHERE THERE ARE NUMEROUS SHOWERS AND
TSTMS. HOWEVER THIS ACTIVITY APPEARS TO BE WEAKENING OVER THE
PAST FEW HOURS. SIMILAR WEATHER IS OCCURRING IN THE BAY OF
CAMPECHE ASSOCIATED WITH A SLOW MOVING TROPICAL WAVE AIDED BY
UPPER DIFFLUENCE BETWEEN THE UPPER LOW IN THE CENTRAL GULF AND A
UPPER RIDGE OVER S MEXICO. THE THIRD AREA OF UNSETTLED WEATHER
IS ALONG THE GULF COAST AND COASTAL WATERS MOSTLY N OF 28N
ASSOCIATED WITH A COLD FRONT JUST N OF THE AREA. THE COLD FRONT
MAY SAG SLOWLY SOUTHWARD INTO THE N GULF WHILE WEAKENING TONIGHT
AND TOMORROW. MODELS KEEP A FAIR AMOUNT OF MOISTURE IN THE
REGION OVER THE NEXT COUPLE OF DAYS.

CARIBBEAN SEA...
SCATTERED MODERATE CONVECTION IS OVER PARTS OF NORTHERN CENTRAL
AMERICA AND S MEXICO GENERATED BY A TROPICAL WAVE IN THE BAY OF
CAMPECHE AND UPPER DIFFLUENCE. SIMILAR WEATHER IS OCCURRING OVER
NORTHERN S AMERICA...PANAMA AND COSTA RICA HIGHLY CONTRIBUTED TO
THE ITCZ. SCATTERED SHOWERS AND TSTMS HAVE ALSO BLOSSOMED OVER
CUBA ENHANCED BY LOCAL EFFECTS. MUCH OF THE CENTRAL AND EASTERN
CARIBBEAN IS QUIET WITH AN UPPER TROUGH COVERING THIS REGION.
DRY/STABLE AIR ACCOMPANIES THE TROUGH. THIS STABLE AIR IS
SUPPRESSING ANY SIGNIFICANT CONVECTION FROM FORMING WITH ONLY
SMALL ISOLATED SHOWERS E OF 75W. A WEAK TROPICAL WAVE IS ALONG
67W INDUCING ONLY A FEW SHOWERS OVER PUERTO RICO...HISPANIOLA
AND THE VIRGIN ISLANDS. TRADE WINDS HAVE INCREASED SLIGHTLY
TODAY TO NEAR 20-25 KT IN SPOTS. THESE WINDS ARE LIKELY TO
INCREASE FURTHER TOMORROW WITH GALE FORCE WINDS EXPECTED SUNDAY
NIGHT. LITTLE CHANGES IN MOISTURE ARE EXPECTED TOMORROW.

ATLANTIC OCEAN...
UPPER DIFFLUENCE BETWEEN AN UPPER RIDGE OVER CUBA AND THE
BAHAMAS...AN UPPER LOW OVER THE GULF AND AN UPPER LOW W OF
BERMUDA IS PRODUCING AN ABUNDANT AMOUNT OF MOISTURE IN THE W
ATLC. A LARGE AREA OF SCATTERED SHOWERS AND TSTMS EXTENDS FROM
24N-32N W OF 67W. A BROAD UPPER RIDGE COVERS THE REMAINDER OF
THE ATLC EXTENDING FROM AN UPPER HIGH LOCATED OVER WEST AFRICA.
THERE IS A SHARP MOISTURE CONTRAST NEAR 66W-68W WITH MODERATE TO
STRONG SUBSIDENCE TO THE EAST OF THIS LINE. A WEAK BENIGN CUT
OFF UPPER LOW IS 250 NM N OF PUERTO RICO ENHANCING ISOLATED
SHOWERS. AT THE SURFACE...A BROAD RIDGE DOMINATES THE ATLC
GIVING THE AREA MODERATE ELY WINDS AND MOSTLY FAIR WEATHER.
ACCORDING TO THE 22/2100 UTC SAHARAN AIR LAYER FROM UW-CIMSS...A
LARGE AREA OF DENSE AFRICAN DUST EXTENDS TO THE LESSER ANTILLES.
THE LEADING EDGE OF THE SAHARAN DUST APPEARS TO BE BEHIND THE
CARIBBEAN TROPICAL WAVE LIMITING ANY SIGNIFICANT CONVECTION FROM
DEVELOPING.

$$
CANGIALOSI


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