[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 210048 CCA
TWDAT

TROPICAL WEATHER DISCUSSION...CORRECTED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN JUL 20 2008

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
2345 UTC.

...CORRECTED FOR SHIP CALL SIGN IN SECOND PARAGRAPH...

...SPECIAL FEATURES...

TROPICAL STORM CRISTOBAL AT 21/0000 UTC IS CENTERED NEAR 34.9N
75.4W OR ABOUT 55 NM EAST-NORTHEAST OF CAPE LOOKOUT NORTH
CAROLINA AND ABOUT 20 NM SOUTH-SOUTHEAST OF CAPE HATTERAS NORTH
CAROLINA MOVING NNE AT 7 KT. LATEST MINIMUM CENTRAL PRESSURE AS
REPORTED BY RECONNAISSANCE AIRCRAFT IS 1006 MB. MAXIMUM
SUSTAINED WINDS HAVE INCREASED SLIGHTLY TO 45 KT WITH GUSTS TO
55 KT. PLEASE SEE THE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC AND THE PUBLIC ADVISORY
UNDER MIATCPAT3/ WTNT33 KNHC FOR MORE DETAILS. ALTHOUGH DRY AIR
IN THE MID TO UPPER LEVELS IS SURROUNDING THE SYSTEM DEEP
CONVECTION IS NOW DEVELOPING NEAR THE LOW LEVEL CENTER.
HOWEVER...THE BULK OF THE THUNDERSTORM ACTIVITY IS LOCATED
OFFSHORE S OF THE CENTER FROM ONSLOW BAY ESE TO ABOUT 65 NM S OF
CAPE HATTERAS AS INDICATED BY THE WILMINGTON AND MOREHEAD CITY
WSR-88D SITES.

TROPICAL STORM DOLLY AT 21/0000 IS CENTERED NEAR 19.3N 85.5W OR
ABOUT 105 NM SOUTHEAST OF COZUMEL MEXICO MOVING NW AT 12 KT.
MINIMUM CENTRAL PRESSURE RECENTLY REPORTED BY A NOAA
RECONNAISSANCE AIRCRAFT WAS 1007 MB. MAXIMUM SUSTAINED WINDS
ARE 40 KT WITH GUSTS TO 50 KT. PLEASE SEE THE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC
AND THE PUBLIC ADVISORY UNDER MIATCPAT4/WTNT34 KNHC FOR MORE
DETAILS. DOLLY IS CONTINUING TO BECOME BETTER ORGANIZED WITH
SCATTERED TO NUMEROUS STRONG THUNDERSTORMS DEVELOPING WITHIN
90 NM OF THE LOW LEVEL BUT CONFINED TO THE NORTHEAST QUADRANT.
UPPER LEVEL OUTFLOW IS BECOMING VERY SYMMETRIC IN ALL QUADRANTS
AND IS SPREADING OVER THE SE HALF OF THE GULF OF MEXICO. AN
ADDITIONAL BAND OF SCATTERED STRONG THUNDERSTORMS IS OVER THE
FLORIDA STRAITS N OF CUBA ABOUT 120 NM SW OF KEY WEST. A SHIP
WITH CALL SIGN C6MN5 NEAR 23.5N 82.2W REPORTED 30 KT WINDS IN
THIS OUTER RAIN BAND IN THE STRAITS OF FLORIDA.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 37W S OF 13N MOVING W NEAR 17 KT. THIS IS
A LOW AMPLITUDE WAVE SOME MID LEVEL ROTATION EMBEDDED WITHIN THE
ITCZ NEAR 6N WITH ONLY ISOLATED MODERATE CONVECTION ASSOCIATED
WITH THE WAVE AT THIS TIME.

TROPICAL WAVE IN THE E CARIBBEAN ALONG 64W S OF 18N IS MOVING W
20 KT. ONLY ISOLATED LOW TOP SHOWERS ARE NOTED IN ASSOCIATION
WITH THE WAVE MAINLY S OF 17N BETWEEN 60W-68W INCLUDING THE
WINDWARD ISLANDS.

TROPICAL WAVE NOTED EARLIER ALONG 95W S OF 21N HAS MOVED W OF
THE AREA. PLEASE REFER TO THE MIATWDEP FOR ADDITIONAL DETAILS.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 12N16W 10N23W 5N43W 8N60W. SCATTERED
MODERATE/STRONG CONVECTION HAS MOVED OFF THE COAST OF W AFRICA
WITHIN 60 NM OF THE AXIS BETWEEN 18W-21W. SCATTERED MODERATE
CONVECTION WAS NOTED ELSEWHERE FROM 6N-10N BETWEEN 16W-23W...
AND WITHIN 90-120 NM OF THE AXIS BETWEEN 30W-34W AND 43W-49W.

...DISCUSSION...

GULF OF MEXICO...
ALL EYES ARE ON THE GULF OF MEXICO AS T.S. DOLLY CHURNS IN THE
NW CARIBBEAN WITH OUTER RAINBANDS SPREADING ACROSS THE STRAITS
OF FLORIDA N OF CUBA AND THE SE GULF S OF 25N E OF 89W. REFER TO
SPECIAL FEATURES ABOVE FOR ADDITIONAL INFORMATION ON DOLLY.
WEAK NARROW UPPER RIDGE IN THE NW GULF BUT IS BEING PINCHED BY
AN APPROACHING UPPER LOW MOVING ACROSS THE BAY OF CAMPECHE.
THE ASSOCIATED UPPER RIDGE EXTENDS S INTO THE BAY OF CAMPECHE
WITH DRIER UPPER AIR NOTED AHEAD OF T.S. DOLLY. AT THE SURFACE
A RIDGE WAS ANCHORED BY A 1021 MB HIGH OFF THE LOUISIANA COAST
NEAR 29N93W. THE REMAINDER OF THE GULF REMAINS CLEAR WITH
SCATTERED LOW CLOUDS IN INCREASING NE FLOW OVER THE SOUTHER
GULF. EXPECT CONDITIONS TO DETERIORATE OVER A LARGER AREA OF THE
SE GULF AS DOLLY APPROACHES THE YUCATAN PENINSULA AND EVENTUALLY
INTO THE GULF OF MEXICO.

CARIBBEAN SEA...
MAIN CONCERN FOR THE CARIBBEAN IS TROPICAL STORM DOLLY IN THE NW
CARIBBEAN...SEE SPECIAL FEATURES ABOVE. OTHERWISE...THE ITCZ
AXIS EXTENDS ACROSS THE SW CARIBBEAN FROM COLOMBIA TO THE BORDER
OF PANAMA/COSTA RICA GENERATING CLUSTERS OF SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS WITHIN 90 NM ALONG THE COAT OF
PANAMA...COSTA RICA...AN NICARAGUA S OF 13N. THE REMAINDER OF
THE CARIBBEAN REMAINS VOID OF SIGNIFICANT PRECIPITATION WITH LOW
CLOUDS SWEEPING WESTWARD IN MODERATE EASTERLY FLOW.

ATLANTIC OCEAN...
T.S. CRISTOBAL IS BRUSHING CAPE HATTERAS NORTH CAROLINA THIS
AFTERNOON...SEE SPECIAL FEATURES ABOVE. BROAD UPPER LEVEL
ANTICYCLONE CENTERED OVER CENTRAL CUBA IS DRAWING SOME UPPER
MOISTURE S OF T.S. CRISTOBAL OVER THE FAR W ATLC BUT WITH DRIER
AIR AT THE SURFACE...NOT PRODUCING ANY SIGNIFICANT SHOWER
ACTIVITY. A VERY SMALL WEAK UPPER LOW IS IN THE W ATLC NEAR
27N64W WITH A 1018 MB SURFACE LOW NEAR 28N62W. A SURFACE TROUGH
EXTENDS FROM A 1020 MB LOW NEAR 31N56W SOUTHWEST TO THE FIRST
LOW THEN ENDS NEAR 26N70W. SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS ARE NOTED WITHIN 120 NM EITHER SIDE OF THE SURFACE
TROUGH. THE REMAINDER OF CENTRAL AND E ATLC IS UPPER RIDGE AND A
SURFACE RIDGE EXTENDS THROUGH THE AZORES SW TO 32N50W THEN W TO
A 1022 MB HIGH NW OF BERMUDA NEAR 33N67W. STRONG SUBSIDENCE AND
DRY STABLE AIR IS KEEPING MOST OF THE ATL FAIR THIS
EVENING.

$$
COBB






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