[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 161057
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON MAY 16 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
1015 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ANALYZED FROM 02N48W TO 10N44W MOVING W AT
10-15 KT. TOTAL PRECIPITABLE WATER IMAGERY DEPICTS A NORTHWARD
BULGE OF LOW-LEVEL MOISTURE IN THE VICINITY OF THE WAVE AXIS.
GLOBAL MODEL GUIDANCE IN THE LOW TO MIDDLE LEVELS ALSO INDICATES
WEAK TROUGHING BETWEEN 40W-50W. ISOLATED MODERATE CONVECTION IS
FROM 03N-08N BETWEEN 40W-51W.

...ITCZ...

ITCZ AXIS IS ALONG 07N11W 04N23W TO A SURFACE TROUGH FROM
02N-07N ALONG 24W. SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION IS WITHIN 120 NM EITHER SIDE OF THE AXIS BETWEEN
12W-19W...AND FROM THE EQUATOR TO 05N BETWEEN 21W-28W. THE ITCZ
AXIS RESUMES NEAR THE EQUATOR AND 41W THEN INTERSECTS THE
TROPICAL WAVE NEAR 02N47W. SCATTERED MODERATE CONVECTION IS FROM
THE EQUATOR TO 03N BETWEEN 42W-45W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES MOSTLY DRY NW FLOW IS LOCATED
ALOFT OVER THE GULF BASIN AS AN UPPER LEVEL TROUGH SHIFTS
EASTWARD INTO THE SW NORTH ATLC THIS MORNING. AS OF 16/0900
UTC...THE SOUTHERN EXTENT OF THE WEAKENING COLD FRONT WAS
ANALYZED ACROSS THE EASTERN STRAITS OF FLORIDA TO THE YUCATAN
CHANNEL. WEST OF THIS FRONT ACROSS THE ENTIRE GULF...A SURFACE
RIDGE IS BUILDING IN OVER WESTERN PORTIONS AND IS ANCHORED BY A
1016 MB HIGH CENTERED NEAR 27N97W. WHILE NORTHERLY WINDS IN THE
RANGE OF 10 TO 15 KT ARE EXPECTED THROUGH THE MORNING HOURS E OF
92W...LIGHT WINDS OVER THE NW GULF AND AREAS ALONG THE MEXICO
GULF COAST W OF 95W WILL CONTINUE TO EXPERIENCE LOW-LEVEL
STRATUS AND POSSIBLE AREAS OF LOWERED VISIBILITY THROUGH THE
LATE MORNING HOURS.

CARIBBEAN SEA...
WITH BROAD UPPER LEVEL TROUGHING LOCATED OVER THE SW NORTH ATLC
WATERS...GENERALLY DRY W-NW FLOW ALOFT IS NOTED ON WATER VAPOR
IMAGERY THIS MORNING. THIS IS PROVIDING FOR OVERALL FAIR
CONDITIONS AND CLEAR SKIES OVER MUCH OF THE WESTERN CARIBBEAN W
OF 74W. AS NOTED IN THE GULF OF MEXICO...A WEAKENING COLD FRONT
EXTENDS ACROSS THE YUCATAN CHANNEL. MOST OF THE UPPER LEVEL
DYNAMICS SUPPORTING THE COLD FRONT REMAIN N OF 25N IN THE W
ATLC...WHILE ONLY A SUBTLE WIND SHIFT AND LACK OF SIGNIFICANT
CONVECTION ARE ASSOCIATED WITH THE COLD FRONT. OVER THE EASTERN
CARIBBEAN...MOSTLY SOUTHWESTERLY FLOW ALOFT IS NOTED EAST OF THE
UPPER LEVEL TROUGH AXIS AND THIS SUPPORTS A SURFACE TROUGH THAT
IS ANALYZED FROM WESTERN HISPANIOLA NEAR 20N74W TO NW VENEZUELA
NEAR 12N70W. TOTAL PRECIPITABLE WATER IMAGERY INDICATES AN
ABUNDANT AMOUNT OF LOW TO MIDDLE LEVEL MOISTURE IS IN PLACE EAST
OF THE SURFACE TROUGH SUSTAINING NUMEROUS SHOWERS CURRENTLY
LOCATED E OF 70W. THE OVERALL DIFFLUENT PATTERN IS EXPECTED TO
PERSIST OVER THE EASTERN CARIBBEAN THROUGH LATE TUESDAY WITH THE
SURFACE TROUGHING FORECAST TO REMAIN NEARLY STATIONARY OVER THE
CENTRAL CARIBBEAN AS WELL OVER THE NEXT COUPLE OF DAYS.

ATLANTIC OCEAN...
AN UPPER LEVEL LOW IS LOCATED OVER THE GREAT LAKES REGION THIS
MORNING AND EXTENDS AN UPPER LEVEL TROUGH AXIS THROUGH 32N80W TO
THE SE BAHAMAS NEAR 22N73W. THIS UPPER LEVEL TROUGH SUPPORTS A
COLD FRONT ANALYZED INTO THE DISCUSSION AREA NEAR 32N77W THAT
EXTENDS SW TO WESTERN CUBA NEAR 23N82W. INFRARED SATELLITE
IMAGERY AND LIGHTNING DATA SHOW WIDELY SCATTERED SHOWERS AND
TSTMS OCCURRING WITHIN 150 NM EAST OF THE FRONT N OF 23N.
FARTHER EAST...ANOTHER UPPER LEVEL LOW IS CENTERED NEAR 36N47W
AND SUPPORTS A SURFACE TROUGH THAT ENTERS THE DISCUSSION AREA
NEAR 32N44W EXTENDING SW TO 21N51W. ANOTHER SURFACE TROUGH IS
ANALYZED FROM 26N49W TO 22N66W. A LARGE PORTION OF THESE SURFACE
TROUGHS ARE LOCATED EAST OF THE BROAD UPPER LEVEL TROUGH OVER
THE BAHAMAS AND ALONG WITH LOW-LEVEL CONVERGENCE IN THE VICINITY
OF THE BOUNDARIES THEY CONTINUE TO GENERATE A RATHER LARGE AREA
OF SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 360 NM EITHER
SIDE OF A LINE FROM 32N40W TO 18N63W. THE REMAINDER OF THE
EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED
BY A 1034 MB HIGH CENTERED NW OF THE IBERIAN PENINSULA NEAR
46N22W. THE SURFACE RIDGE AXIS EXTENDS FROM THE AZORES NEAR
39N30W TO 18N40W.

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

$$
HUFFMAN




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