[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 011208
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON AUG 01 2011

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...SPECIAL FEATURES...

AN ELONGATED AREA OF LOW PRESSURE ANALYZED AS A 1009 MB LOW OVER
200 NM E OF THE LESSER ANTILLES NEAR 14N57W MOVING WNW 10 TO 15
KT PRODUCING SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM
13N-16N BETWEEN 54W-57W AND SCATTERED SHOWERS COVERING A BROADER
AREA FROM 12N-18N W OF 49W TO ACROSS THE LESSER ANTILLES. A
TROPICAL DEPRESSION COULD FORM LATER TODAY. A HURRICANE HUNTER
AIRCRAFT IS CURRENTLY INVESTIGATING THE DISTURBANCE TO DETERMINE
IF IT HAS A WELL-DEFINED SURFACE CIRCULATION CENTER. IF THE
SYSTEM BECOMES A TROPICAL CYCLONE TODAY...TROPICAL STORM
WARNINGS WOULD BE ISSUED FOR PORTIONS OF THE NORTHERN WINDWARD
ISLANDS AND THE LEEWARD ISLANDS ON VERY SHORT NOTICE. INTERESTS
IN THESE AREAS SHOULD CLOSELY MONITOR THE PROGRESS OF THIS
SYSTEM. REGARDLESS OF TROPICAL CYCLONE DEVELOPMENT OF THIS
SYSTEM WILL BRING LOCALLY HEAVY RAINFALL AND GUSTY WINDS TO
PORTIONS OF THE LESSER ANTILLES TODAY AND TONIGHT.

...TROPICAL WAVES...

TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC IS ANALYZED ALONG
44W/45W FROM 13N-23N MOVING W NEAR 15 KT. WAVE IS BENEATH A
BROAD UPPER HIGH AND IS WELL DEFINED IN THE UPPER LEVEL
SATELLITE WINDS. WAVE REMAINS EMBEDDED WITHIN AN AREA OF WEAK
LOW LEVEL MOISTURE AS DEPICTED ON TOTAL PRECIPITABLE WATER
SATELLITE IMAGERY. NO SIGNIFICANT SHOWERS/CONVECTION IS NOTED.

TROPICAL WAVE IN THE W TROPICAL ATLC/E CARIBBEAN IS ANALYZED
FROM 22N61W OVER THE LESSER ANTILLES ALONG 16N62W TO 11N61W
MOVING W 10-15 KT. WAVE REMAINS EMBEDDED WITHIN AN AREA OF DEEP
MOISTURE AS DEPICTED ON TOTAL PRECIPITABLE WATER SATELLITE
IMAGERY AND IS REASONABLY DEFINED IN THE UPPER LEVEL SATELLITE
WINDS. WAVE IS AT THE LEADING EDGE OF THE SHOWER ACTIVITY
ASSOCIATED WITH THE LOW IN THE SPECIAL FEATURES. SCATTERED
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE FROM 11N-18N
BETWEEN 60W-63W.

TROPICAL WAVE IN THE S GULF OF MEXICO IS ANALYZED FROM 24N92W TO
INLAND OVER S MEXICO NEAR 18N94W MOVING W NEAR 15 KT. WAVE IS
EMBEDDED WITHIN A BROAD AREA OF DEEP MOISTURE AS DEPICTED ON
TOTAL PRECIPITABLE WATER SATELLITE IMAGERY. SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS ARE S OF 22N W OF THE WAVE AXIS TO INLAND
OVER MEXICO.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS INTO THE E TROPICAL ATLC OFF THE
AFRICAN COAST NEAR 21N17W ALONG 17N21W 15N27W TO 11N36W. THE
ITCZ AXIS CONTINUES ALONG 9N43W THEN RESUMES NEAR 9N46W 8N51W TO
9N56W AND IS BEING DISTORTED BY THE LOW IN THE SPECIAL FEATURES.
A SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ EXTENDING FROM
11N44W TO 4N47W WITH SCATTERED MODERATE/STRONG CONVECTION FROM
4N-10N W OF THE TROUGH TO 54W. CLUSTERS OF SCATTERED MODERATE/
ISOLATED STRONG CONVECTION ARE WITHIN 90 NM OF 10N BETWEEN
29W-42W AND WITHIN 200 NM E OF THE SURFACE TROUGH BETWEEN
5N-10N.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER RIDGE OVER THE SE CONUS IS GIVING THE GULF NEAR
ZONAL EASTERLY FLOW ALOFT AND IS BEING RE-ENFORCED OVER THE S
GULF BY AN UPPER LOW IN THE W CARIBBEAN INCREASING UPPER LEVEL
WINDS MAINLY OVER THE SE GULF AND GIVING THE SE GULF THROUGH THE
STRAITS OF FLORIDA S OF 26N E OF 84W SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS. AT 01/0900 UTC A WEAK SURFACE TROUGH IS OVER THE
NE GULF EXTENDING FROM SE GEORGIA NEAR 31N82W ACROSS NE FLORIDA
INTO THE GULF NEAR 29N83W TO 28N85W PRODUCING SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS WITHIN 60 NM EITHER SIDE OF THE TROUGH
AXIS. ISOLATED SHOWERS DOT THE IMMEDIATE N GULF COAST WATERS W
OF THE SURFACE TROUGH TO THE LOUISIANA/TEXAS BORDER AND ACROSS
THE CENTRAL GULF WITHIN 90 NM OF LINE FROM 28N85W TO 23N94W. AT
01/0900 UTC A WEAK 1017 MB HIGH IS OFF THE COAST OF LOUISIANA
NEAR 28N93W. THE WEAK SURFACE RIDGE ACROSS THE N GULF WILL
DOMINATE THE REGION THROUGH FRI. THE TROPICAL WAVE WILL MOVE
ACROSS THE SW GULF TODAY THROUGH TUE THEN INLAND TUE NIGHT.

CARIBBEAN SEA...
AN UPPER LOW COVERS THE W CARIBBEAN W OF 81W CENTERED IN THE
GULF OF HONDURAS NEAR 18N86W PRODUCING SCATTERED TO HEAVY
SHOWERS WITH POSSIBLE ISOLATED THUNDERSTORMS FROM 14N-19N W OF
82W TO INLAND OVER CENTRAL AMERICA AND THE YUCATAN PENINSULA.
THESE RAINS COULD PRODUCE FLASH FLOODING AND MUDSLIDES OVER
PORTIONS OF NICARAGUA...HONDURAS...BELIZE...AND GUATEMALA.
CLUSTERS OF SCATTERED SHOWERS/THUNDERSTORMS ARE N OF 19N TO OVER
CUBA BETWEEN 80W-84W. UPPER RIDGE COVERS THE REMAINDER OF THE
CARIBBEAN ANCHORED E OF THE LESSER ANTILLES AND IS INDUCING AN
INVERTED UPPER TROUGH ACROSS THE CENTRAL CARIBBEAN FROM CENTRAL
PANAMA TO HAITI GENERATING CLUSTERS OF SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS N OF 19N TO OVER E CUBA BETWEEN
74W-78W AND FROM 10N-12N BETWEEN 74W-77W INCLUDING THE COAST OF
COLOMBIA. THIS IS LEAVING THE REMAINDER OF THE CARIBBEAN UNDER
CLEAR SKIES THIS MORNING. TROPICAL WAVE THROUGH THE E CARIBBEAN
TODAY AND THE CENTRAL CARIBBEAN BY TUE. THE SURFACE LOW IN THE
SPECIAL FEATURES WILL MOVE ACROSS THE NE CARIBBEAN TUE THROUGH
WED...POSSIBLY AS A TROPICAL CYCLONE.

ATLANTIC OCEAN...
THE PRIMARY CONCERN THIS MORNING REMAINS THE LOW IN THE SPECIAL
FEATURES ABOVE. THE UPPER RIDGE OVER THE SE CONUS EXTENDS INTO
THE W ATLC OFF THE GEORGIA COAST TO 30N70W COVERING THE W ATLC
WITH A WEAK SURFACE RIDGE. A PAIR OF UPPER LOWS ARE IN THE
CENTRAL ATLC NEAR 27N56W AND 28N44W BUT ARE NOT PRODUCING ANY
SIGNIFICANT WEATHER. A LARGE SURFACE RIDGE DOMINATES THE ATLC
ANCHORED BY A 1026 MB HIGH N OF THE DISCUSSION AREA AND ABOUT
300 NM WSW OF THE AZORES. A LARGE AREA OF SAHARAN DUST IS
OBSERVED ON THE FIRST VISIBLE SATELLITE IMAGES FROM 13N-28N E OF
45W. WEAK SURFACE RIDGE OVER THE W ATLC WILL PERSIST THROUGH MON
NIGHT THEN SHIFT S TO NEAR 26N TUE. THE SURFACE LOW IN THE
SPECIAL FEATURES WILL MOVE FROM THE NE CARIBBEAN INTO THE SW
ATLC LATE WED OR EARLY THU AND FRI POSSIBLY AS A TROPICAL
CYCLONE.

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

$$
PAW






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