[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210000
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE JUL 20 2010

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND 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
2350 UTC...

...SPECIAL FEATURES...

AN AREA OF DISTURBED WEATHER REMAINS ACROSS HISPANIOLA...PUERTO
RICO...AND NORTHERN LEEWARD ISLANDS ASSOCIATED WITH A TROPICAL
WAVE THAT HAS NOW MOVED OVER EASTERN CUBA. SEE THE TROPICAL WAVE
SECTION FOR MORE DETAILS ABOUT THE WAVE. A SURFACE TROUGH IS
LEFT IN ITS WAKE EXTENDING FROM 22N67W TO 16N66W. STRONG SURFACE
CONVERGENCE NEAR THE TROUGH ALONG WITH DIFFLUENCE ALOFT ARE
ENHANCING SCATTERED MODERATE TO STRONG CONVECTION FROM 15N-23N
BETWEEN 60W-70W. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO BE
FAVORABLE FOR TROPICAL CYCLONE FORMATION AS THE SYSTEM MOVES
WEST-NORTHWESTWARD AT ABOUT 10 MPH DURING THE NEXT DAY OR SO.
LOCALLY HEAVY RAINFALL AND GUSTY WINDS WILL LIKELY CONTINUE TO
AFFECT THE NORTHERN LEEWARD ISLANDS ISLANDS...PUERTO RICO...
HISPANIOLA...EASTERN CUBA...THE TURKS AND CAICOS ISLANDS...AND
THE BAHAMAS DURING THE NEXT COUPLE OF DAYS. THE HEAVY RAINS
COULD CAUSE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES IN
MOUNTAINOUS AREAS WHERE TERRAIN HAS BECOME SATURATED.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 36W/37W S OF 25N MOVING W 15-20 KT.
SATELLITE IMAGERY INDICATES CLEAR LOW-LEVEL CYCLONIC FLOW ABOUT
THE WAVE AXIS WITH AN INVERTED-V STRUCTURE. A SURGE OF DEEP
LAYER MOISTURE IS ALSO PRESENT IN TOTAL PRECIPITABLE WATER
IMAGERY. SCATTERED WEAK CONVECTION IS FROM 20N TO 30N BETWEEN
35W AND 42W.

TROPICAL WAVE IS ACROSS EASTERN CUBA ALONG 75W S OF 21N MOVING
W NEAR 15 KT. MID-LEVEL CYCLONIC FLOW IS IN THE VICINITY OF THE
WAVE AXIS. THIS WAVE PASSED OVER PUERTO RICO AND THE DOMINICAN
REPUBLIC OVER THE PAST DAY OR SO...PRODUCING SIGNIFICANT
CONVECTION AS IT INTERACTED WITH AN UPPER LEVEL LOW. THIS
CONVECTION REMAINS OVER THOSE AREAS AND IS NOW ASSOCIATED WITH
A SURFACE TROUGH. SEE SPECIAL FEATURES ABOVE. THE WAVE IS NOW
ENHANCING ISOLATED MODERATE/STRONG CONVECTION WITHIN 90 NM
EITHER SIDE OF THE AXIS.

TROPICAL WAVE IS IN THE CENTRAL GULF AND ACROSS THE YUCATAN
PENINSULA ALONG 89W S OF 28N TO NORTHERN GUATEMALA MOVING W NEAR
10 KT. WAVE LIES EMBEDDED WITHIN A LARGE AREA OF DEEP LAYER
MOISTURE THAT IS MOVING ACROSS THE NW CARIBBEAN AND CENTRAL
AMERICA. MID-LEVEL CYCLONIC FLOW IS AROUND THE WAVE AXIS
INDICATED BY VISIBLE SATELLITE IMAGERY. SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION IS FROM 17N-25N BETWEEN
76W-91W...INCLUDING INLAND PORTIONS OF CUBA AND THE YUCATAN
PENINSULA.

TROPICAL WAVE IS OVER THE FAR SW GULF OF MEXICO EXTENDING FROM
23N96W TO 17N94W MOVING W NEAR 8 KT. WAVE LIES EMBEDDED WITHIN
A MAXIMUM IN DEEP LAYER MOISTURE THAT COVERS THE WRN GULF
EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE
TO ISOLATED STRONG CONVECTION IS S OF 22N W OF 93W ACROSS THE
WESTERN BAY OF CAMPECHE. THIS WAVE IS EXPECTED TO WEAKEN AS IT
MOVES OVER HIGHER TERRAIN IN MEXICO.

...ITCZ...

THE ITCZ AXIS IS ANALYZED FROM THE WESTERN AFRICAN COASTLINE OF
GUINEA NEAR 10N14W...WESTWARD ALONG 8N20W 10N30W 8N40W 9N50W
10N60W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS
WITHIN 180 NM ON EITHER SIDE OF THE ITCZ AXIS BETWEEN 14W AND
26W. SCATTERED WEAK CONVECTION IS WITHIN 100 NM ON EITHER SIDE
OF THE ITCZ WEST OF 26W.

...DISCUSSION...

GULF OF MEXICO...
TWO TROPICAL WAVES ARE ANALYZED IN THE GULF OF MEXICO. ONE IN
THE FAR SW GULF AND THE OTHER ONE OVER THE CENTRAL GULF. THESE
TWO SYSTEMS ARE BRINGING SIGNIFICANT MOISTURE TO THE GULF AND
ENHANCING HEAVY SHOWERS AND THUNDERSTORMS ACROSS THE SOUTHERN
HALF OF THE BASIN S OF 25N. SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS ARE N OF 25N. SEE TROPICAL WAVES SECTION
ABOVE FOR MORE DETAILS. ELSEWHERE ALOFT...AN UPPER LEVEL LOW IS
OVER THE WESTERN GULF 24N94W ENHANCING CONVECTION NEAR THE
TROPICAL WAVE IN THE FAR WEST GULF. EXPECT SHOWERS AND
THUNDERSTORMS TO CONTINUE ACROSS MUCH OF THE BASIN AS THE
TROPICAL WAVES MOVE WWD.

CARIBBEAN SEA...
SIGNIFICANT MOISTURE AND UNSTABLE CONDITIONS ARE OBSERVED ACROSS
MUCH OF THE NORTHERN CARIBBEAN..ASSOCIATED WITH A SERIES OF
TROPICAL WAVES AND A SURFACE TROUGH. SEE TROPICAL WAVES SECTION
ABOVE FOR MORE DETAILS. THE SURFACE TROUGH IS LOCATED ACROSS THE
EASTERN COAST OF DOMINICAN REPUBLIC ENHANCING NUMEROUS SHOWERS
AND THUNDERSTORMS ACROSS HISPANIOLA...PUERTO RICO...AND THE
NORTHERN LEEWARD ISLANDS. THIS AREA OF DISTURBED WEATHER HAS THE
POTENTIAL TO DEVELOP INTO A TROPICAL DEPRESSION OR STORM DURING
THE NEXT FEW DAYS. SEE SPECIAL FEATURES ABOVE FRO MORE INFO.
WATER VAPOR IMAGERY INDICATES AN AREA OF DRY AIR OVER THE S
CENTRAL AND SE CARIBBEAN WHICH IS KEEPING CONDITIONS FAIR ACROSS
THESE AREAS. EXPECT CONTINUED SHOWER ACTIVITY ACROSS MUCH OF THE
N CENTRAL AND WRN CARIBBEAN AS THE TROPICAL WAVES MOVE WWD. THE
NE CARIBBEAN IS ALSO EXPECTED TO CONTINUE TO RECEIVE SIGNIFICANT
RAINFALL AS THE AREA OF DISTURBED WEATHER MENTIONED IN THE
SPECIAL FEATURES MOVES WNW.

ATLANTIC OCEAN...
MODERATE DRY AIR ALOFT COMBINED WITH SURFACE RIDGING IS
MAINTAINING FAIR WEATHER ACROSS THE WESTERN ATLC W OF 70W. AN
AREA OF DISTURBED WEATHER ACROSS THE NE CARIBBEAN EXTENDS INTO
THE ATLC ASSOCIATED WITH A SURFACE TROUGH EXTENDING FROM NEAR
22N67W ACROSS THE EASTERN COAST OF DOMINICAN REPUBLIC INTO THE
CARIBBEAN. SATELLITE IMAGERY INDICATES SCATTERED MODERATE TO
HEAVY SHOWERS AND THUNDERSTORMS COVERING FROM 18N TO 27N BETWEEN
61W AND 70W...ESPECIALLY WITHIN 160 NM NORTH OF PUERTO RICO
NOTED BY DOPPLER RADAR IMAGERY. SEE SPECIAL FEATURES ABOVE FOR
MORE DETAILS ON THIS AREA OF DISTURBED WEATHER. THE REMAINDER OF
THE BASIN IS DOMINATED BY SURFACE RIDGING AROUND A 1027 MB NEAR
35N40W. A WEAK SURFACE TROUGH IS EMBEDDED WITHIN THE RIDGE ALONG
32N49W TO 28N51W. POSSIBLE ISOLATED SHOWERS ARE WITHIN 90 NM NW
OF THE AXIS. A TROPICAL WAVE OVER THE CENTRAL TROPICAL ATLANTIC
SPREADS SOME WEAK CONVECTION NORTHWARD FROM 20N TO 30N BETWEEN
35W AND 42W. SEE TROPICAL WAVES DISCUSSION FOR MORE INFO
REGARDING THIS WAVE.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$

GARCIA



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