[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 132344
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE JUL 13 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
2315 UTC...


...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 35W/36W S OF 18N MOVING W 15-20 KT. THERE
IS A MID LEVEL CYCLONIC ROTATION NW OF THE WAVE AXIS NEAR
17N38W. WAVE IS EMBEDDED WITHIN A WEAK MOISTURE MAXIMUM AS
INDICATED ON THE TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...THE
TROPICAL ATLC IS DOMINATED BY DRY SAHARAN AIR AND DUST N OF 10N.
THEREFORE THE SATELLITE SIGNATURE IS PARTIALLY MASKED AND THERE
IS NO ASSOCIATED SHOWERS/CONVECTION.

TROPICAL WAVE IS ALONG 55W/56W S OF 14N MOVING W NEAR 20 KT.
WAVE IS MOSTLY EMBEDDED WITHIN DRY SAHARAN AIR AND DUST MASKING
ANY SATELLITE SIGNATURE AND SUPPRESSING ANY SHOWER ACTIVITY/
CONVECTION.

TROPICAL WAVE IN THE S GULF OF MEXICO IS ALONG 93W S OF 20N
MOVING W NEAR 20 KT. THIS WAVE IS MOSTLY IN THE E PACIFIC REGION
WITH LITTLE SATELLITE SIGNATURE IN THE GULF AND IS EMBEDDED
WITHIN AN AREA OF DEEP LAYER MOISTURE THAT COVERS THE S GULF AS
INDICATED ON THE TOTAL PRECIPITABLE WATER IMAGERY. A LARGE AREA
OF DRY SAHARAN AIR AND DUST COVERS THE TROPICAL ATLC INTO THE
CARIBBEAN COVERS THE S GULF S OF 23N THUS LIMITING ANY  SHOWER
ACTIVITY/CONVECTION.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 11N15W 8N29W 9N36W 8N46W 9N56W
9N62W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION
ARE WITHIN 200 NM OF THE ITCZ E OF 23W TO INLAND OVER WEST
AFRICA...WITHIN 150 NM OF THE ITCZ BETWEEN 36W-42W...FROM 4N-7N
BETWEEN 43W-50W...AND FROM 9N-13N BETWEEN 42W-49W. CLUSTERS OF
SCATTERED MODERATE CONVECTION ARE WITHIN 180 NM OF THE ITCZ
BETWEEN 26W-31W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER RIDGE COVERS THE GULF N OF 27N AND THE ENTIRE E
GULF WITH THE AXIS EXTENDING ALONG THE N GULF COAST FROM TEXAS
INTO THE W ATLC OVER S GEORGIA. A WEAK UPPER LOW HAS MOVED
INLAND OVER MEXICO NEAR 23N100W DRAWING TROPICAL MOISTURE FROM
THE E PACIFIC REGION OVER THE SW GULF AND DRAWING THE AFTERNOON
THUNDERSTORMS THAT DEVELOPED OVER THE YUCATAN PENINSULA INTO THE
E BAY OF CAMPECHE TO WITHIN 60 NM ALONG THE COAST S OF 21N E OF
92W. A WEAK SURFACE RIDGE EXTENDS FROM THE W ATLC ACROSS THE
FLORIDA PENINSULA OVER THE E GULF WITH A 1019 MB HIGH NEAR
26N85W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE INLAND OVER
GEORGIA AND THE FLORIDA PENINSULA WITH ISOLATED SHOWERS MOVING
INTO FLORIDA BAY N OF THE FLORIDA KEYS. MODERATE SUBSIDENCE AND
DRY STABLE AIR ALOFT COVER THE W GULF. CLEAR SKIES DOMINATE THE
REMAINDER OF THE GULF THIS EVENING.

CARIBBEAN SEA...
THE UPPER RIDGE OVER THE W ATLC AND MOST OF THE GULF OF MEXICO
IS GIVING THE NW CARIBBEAN EASTERLY FLOW ALOFT. A SECOND UPPER
RIDGE ANCHORED IN THE W TROPICAL ATLC IS GIVING THE E CARIBBEAN
SE TO S FLOW ALOFT AND INDUCING AN INVERTED UPPER TROUGH THAT
EXTENDS FROM E PANAMA NE TO THE MONA PASSAGE. THE ITCZ EXTENDS
ACROSS THE E PACIFIC REGION JUST S OF PANAMA AND COUPLED WITH
THE CONVERGENCE OF MODERATE TO FRESH SURFACE WINDS AND THE FLOW
ALOFT ARE GIVING THE AREA W OF A LINE FROM PANAMA NEAR 9N78W TO
THE TIP OF NICARAGUA/HONDURAS SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS TO INLAND OVER CENTRAL AMERICA. SCATTERED CLUSTERS
OF SHOWERS/ISOLATED THUNDERSTORMS ARE N OF 14N TO OVER THE
GREATER ANTILLES E OF 80W TO OVER THE LEEWARD ISLANDS INCLUDING
E CUBA...JAMAICA...HISPANIOLA...PUERTO RICO...AND THE VIRGIN
ISLANDS. A WEAK SURFACE TROUGH EXTENDS FROM THE CAYMAN ISLANDS
ACROSS CENTRAL CUBA TO OVER THE N BAHAMA ISLANDS WITH
SCATTERED/HEAVY SHOWERS AND SCATTERED THUNDERSTORMS INLAND AND
ALONG THE IMMEDIATE COAST OF W CUBA W OF 80W. A SWATH OF DRY
STABLE AIR COVERS THE NW CARIBBEAN N OF 16N W OF 80W.

ATLANTIC OCEAN...
AN UPPER RIDGE EXTENDS ACROSS THE N GULF OF MEXICO OFF THE
GEORGIA COAST TO BEYOND 32N76W GIVING THE W ATLC NE FLOW ALOFT.
A SURFACE TROUGH EXTENDS FROM THE CAYMAN ISLANDS IN THE
CARIBBEAN ACROSS CENTRAL CUBA TO OVER THE N BAHAMA ISLANDS NEAR
26N76W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM
THE BAHAMA ISLANDS TO CUBA BETWEEN 75W-80W. AN UPPER LOW IS N OF
MONA PASSAGE NEAR 21N68W BUT IS NOT PRODUCING ANY SIGNIFICANT
WEATHER. A SURFACE RIDGE DOMINATES THE ATLC E OF 75W ANCHORED BY
A 1032 MB HIGH WELL N OF THE DISCUSSION AREA THEN WEAKENS OVER
THE REMAINDER OF THE W ATLC AND INTO THE GULF OF MEXICO ACROSS
THE FLORIDA PENINSULA. THE CENTRAL ATLC AND E ATLC ARE UNDER
STRONG SUBSIDENCE AND DRY STABLE AIR ALOFT LEAVING THE AREA
UNDER FAIR WEATHER THIS EVENING.

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

$$
PAW





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