[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 202348
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI MAY 20 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 66W/67W S OF 13N TO INLAND OVER SOUTH
AMERICA MOVING W 10-15 KT. WAVE REMAINS EMBEDDED WITHIN AN AREA
OF DEEP LAYERED MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE
WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
INLAND OVER VENEZUELA.

...THE ITCZ...

ITCZ AXIS IS ANALYZED ALONG 10N14W 5N21W 3N33W 1N40W S OF THE
EQUATOR NEAR 46W TO INLAND OVER SOUTH AMERICA. CLUSTERS OF
SCATTERED/NUMEROUS STRONG CONVECTION ARE FROM 1N-10N BETWEEN
11W-18W INCLUDING THE INLAND OVER SIERRA LEONE. CLUSTERS OF
SCATTERED MODERATE/STRONG CONVECTION ARE WITHIN 90/120 NM EITHER
SIDE OF THE ITCZ BETWEEN 19W-26W. CLUSTERS OF SCATTRED MODERATE/
ISOLATED STRONG CONVECTION ARE FROM THE EQUATOR TO 5N BETWEEN
27W-37W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD LOW AMPLITUDE UPPER RIDGE COVERS MOST OF THE GULF WITH
THE AXIS EXTENDING FROM THE E PACIFIC REGION ACROSS THE BAY OF
CAMPECHE TO OVER THE N GULF COAST NEAR THE MISSISSIPPI DELTA OF
LOUISIANA AND COUPLED WITH THE BROAD UPPER TROUGH OVER NEW
ENGLAND AND THE W ATLC IS GIVING THE GULF WATERS NW FLOW ALOFT.
SOMEWHAT DRY STABLE AIR ALOFT COVERS MUCH OF THE GULF LIMITING
SHOWER ACTIVITY. DENSE SMOKE REMAINS OVER THE W GULF W OF 90W
FROM FIRES REPORTED OVER S MEXICO AND THE YUCATAN PENINSULA ON
NOAA SSD FIRE PRODUCTS. A WEAK SURFACE RIDGE REMAINS OVER THE NE
GULF GIVING THE GULF E TO SE SURFACE FLOW AND LEAVING THE THE
GULF UNDER MOSTLY CLEAR SKIES THIS EVENING. WEAK SURFACE RIDGE
WILL REMAIN NEARLY STATIONARY IN THE NE GULF THROUGH TUE. FRESH
RETURN FLOW WILL CONTINUE OVER THE W GULF THROUGH TUE. THEN
DIMINISH WED AS A COLD FRONT APPROACHES THE TEXAS GULF COAST.

CARIBBEAN SEA...
A BROAD SHORTWAVE UPPER TROUGH EXTENDS ACROSS E CUBA NEAR 20N78W
TO THE SW CARIBBEAN NEAR THE PANAMA/COSTA RICA BORDER A SURFACE
TROUGH EXTENDS ALONG THE E SIDE OF THE UPPER TROUGH FROM 17N71W
TO INLAND OVER SOUTH AMERICA NEAR 12N72W WITH ISOLATED SHOWERS
WITHIN 60 NM EITHER SIDE OF THE TROUGH AXIS. A BROAD UPPER RIDGE
COVERS THE E CARIBBEAN E OF 70W WITH THE AXIS E OF THE LESSER
ANTILLES. DEEP LAYERED MOISTURE REMAINS OVER THE E CARIBBEAN
AND COUPLED WITH THE DIFFLUENT FLOW ALOFT IS GENERATING
SCATTERED SHOWERS OVER THE E CARIBBEAN WITHIN 180 NM OF LINE
FROM 14N69W ACROSS PUERTO RICO AND VIRGIN ISLANDS NEAR 18N65W.
DRY STABLE AIR ALOFT REMAINS OVER THE W CARIBBEAN LEAVING THE
AREA W OF 73W UNDER MOSTLY CLEAR SKIES THIS EVENING. SMOKE IS
OBSERVED ON THE LAST VISIBLE SATELLITE IMAGES OVER THE GULF OF
HONDURAS W OF LINE FROM THE HONDURAS COAST NEAR 16N85W TO THE
YUCATAN PENINSULA N OF BELIZE NEAR 19N87W. SURFACE TROUGH WILL
REMAIN NEARLY STATIONARY THROUGH SAT BEFORE DISSIPATING.

ATLANTIC OCEAN...
AN UPPER TROUGH COVERS THE W ATLC N OF 20N BETWEEN 65W-80W
SUPPORTING A COLD FRONT THAT IS N OF THE REGION. THE SEABREEZE
OVER THE FLORIDA PENINSULA IS GENERATING SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS S 29N. A SURFACE TROUGH IS OVER THE
W/CENTRAL ATLC EXTENDING ALONG 59W/60W FROM 24N-30N. A BROAD
UPPER RIDGE EXTENDS FROM THE TROPICS E OF THE LESSER ANTILLES
ALONG 55W TO BEYOND 32N SUPPLYING DIFFLUENT FLOW ALOFT AND
ENHANCING SCATTERED SHOWERS WITHIN 200 NM OF LINE FROM THE
VIRGIN ISLANDS NEAR 18N65W TO 28N55W. A WEAKENING UPPER TROUGH
IS IN THE N/CENTRAL ATLC IS N OF 29N BETWEEN 30W-45W SUPPORTING
A WEAK SURFACE TROUGH EXTENDING ALONG 29N50W TO BEYOND 32N49W.
THESE SURFACE TROUGHS ARE EMBEDDED WITHIN A BROAD SURFACE RIDGE
THAT COVERS THE ATLC N OF 20N FROM SW AFRICA TO FLORIDA AND INTO
THE NE GULF OF MEXICO. SURFACE RIDGE ALONG 30N IN THE W ATLC
WILL MOVE TO ALONG 28N SAT THEN WILL DRIFT BACK N TO ALONG 30N
MON THROUGH WED.

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

$$
PAW




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