[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 060001
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI JUN 05 2009

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...

A WEAK TROPICAL WAVE IS ALONG 38W S OF 10N MOVING W AT 15 KT.
THE WAVE HAS NO SIGNIFICANT DEEP CONVECTION ASSOCIATED WITH IT
AND IS QUITE DIFFICULT TO TRACK AS NEITHER THE GFS NOR THE ECMWF
SHOWS THE WAVE.  THE ONLY HINT THAT THE WAVE IS STILL VIABLE IS
A SLIGHT MAXIMA IN THE TOTAL PRECIPITABLE WATER IMAGERY NEAR
THE WAVE AXIS.

A TROPICAL WAVE EXTENDS FROM 19N52W TO 12N53W TO 6N53W MOVING W
NEAR 15 KT.  IN CONTRAST TO THE WAVE FARTHER EAST...THIS WAVE IS
WELL-DEFINED FROM ALL AVAILABLE TOOLS.  THE TOTAL PRECIPITABLE
WATER IMAGERY DEPICTS DISTINCT MAXIMA WITH ENHANCED MOISTURE
JUST EAST OF THE WAVE AXIS UP TO 21N.  BOTH THE GFS AND ECMWF
INDICATE THE LARGEST AMPLITUDE OF THE WAVE NEAR 700 MB WITH THE
WAVE AXIS AT THIS LEVEL WEST OF THE SURFACE AXIS.  VISIBLE AND
NEAR-VISIBLE IR IMAGERY ALONG WITH THE GFS SUGGESTS THAT THE
WAVE MAY BE FRACTURING WITH ONE LOW-LEVEL VORT MAX NEAR 19N AND
THE OTHER NEAR 8N.  SCATTERED MODERATE CONVECTION IS FROM 6N-10N
BETWEEN 47W-54W.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N15W 5N22W 2N33W TO THE
EQUATOR AT 50W.  ISOLATED MODERATE CONVECTION IS FROM 2N-5N
BETWEEN 10W-30W.  SCATTERED MODERATE CONVECTION IS ALSO
OCCURRING JUST SOUTH OF NORTHWEST AFRICA NORTH OF 3N BETWEEN
10W-10E.

...DISCUSSION...

GULF OF MEXICO...
AT 2100 UTC...A DISSIPATING COLD FRONT EXTENDS ACROSS THE GULF
FROM THE FLORIDA PENINSULA AT 30N85W SOUTHWESTWARD TO 23N94W.
WHILE THE BAROCLINICITY ASSOCIATED WITH THIS HAS DIMINISHED
TODAY...THE BOUNDARY IS STILL A WELL-DEFINED TROUGH ESPECIALLY
EAST OF 90W.  DURING THE LAST THREE HOURS...THE STRONG
CONVECTION ALONG THE FRONTAL BOUNDARY HAS DIMINISHED.
HOWEVER...SCATTERED MODERATE CONVECTION IS OCCURRING AHEAD OF
THE FRONT OVER THE YUCATAN OF MEXICO...THE EASTERN GULF AND THE
FLORIDA PENINSULA.  BEHIND THE FRONT...DRY LOWER LEVEL AIR HAS
BEEN ADVECTED ACROSS THE WESTERN GULF OF MEXICO.  SURFACE WINDS
AWAY FROM THE DEEP CONVECTION ARE LESS THAN 20 KT.  IN THE UPPER
LEVELS...A HIGH AMPLITUDE SHORT-WAVE MAY BE CUTTING OFF NEAR
30N87W JUST SOUTH OF THE FLORIDA PENINSULA.  THIS STRONG UPPER
TO MID-LEVEL TROUGH IS LIKELY ENHANCING THE CONVECTION THROUGH
PVA AND DIVERGENT FLOW AHEAD OF THE TROUGH.

CARIBBEAN SEA...
NO SIGNIFICANT SURFACE FEATURES ARE OBSERVED TODAY ACROSS THE
CARIBBEAN.  HOWEVER...SCATTERED MODERATE CONVECTION IS OCCURRING
OVER THE YUCATAN OF MEXICO...CUBA...AND HISPANIOLA...PERHAPS
BEING ASSISTED BY THE AFOREMENTIONED UPPER-LEVEL TROUGH.
TOTAL PRECIPITABLE WATER IMAGERY INDICATES THAT THERE EXISTS A
WEDGE OF DRY AIR ACROSS THE CENTRAL CARIBBEAN BETWEEN A
MORE MOIST ENVIRONMENT IN THE NORTHERN AND SOUTHWESTERN
CARIBBEAN.  SOME OF THE ENHANCED MOISTURE IN THE SOUTHWESTERN
CARIBBEAN MAY BE ASSOCIATED WITH A TROPICAL WAVE THAT IS
PRIMARILY IN THE NORTHEAST PACIFIC SOUTH OF CENTRAL AMERICA.
SCATTERED MODERATE CONVECTION IS OCCURRING SOUTH OF 13N WEST OF
73W.  SURFACE WINDS THROUGHOUT THE CARIBBEAN ARE EASTERLY WITH A
MAXIMUM OF UP TO 20 KT IN THE CENTRAL CARIBBEAN NORTH OF
COLOMBIA AND WESTERN VENEZUELA...AS SHOWN BY BUOYS AND QUIKSCAT
WINDS.  IN THE UPPER LEVELS...ANTICYCLONICALLY TURNING WINDS ARE
PREVALENT...WHICH ARE ADVECTING UPPER LEVEL MOISTURE AND
CLOUDINESS FROM THE AFOREMENTIONED CONVECTION ACROSS THE
CARIBBEAN.

ATLANTIC OCEAN...
SCATTERED MODERATE CONVECTION HAS BEEN OCCURRING TODAY NEAR AND
OVER THE BAHAMAS AND FLORIDA AHEAD OF THE GULF FRONT NORTH OF
25N AND WEST OF 73W.  SUBSTANTIAL UPPER LEVEL DIVERGENCE
COMBINED WITH MOIST SOUTHERLY LOW-LEVEL FLOW ARE CONTRIBUTING
TOWARD THE CONVECTIVE ACTIVITY.  ELSEWHERE ACROSS THE
ATLANTIC...MORE TRANQUIL CONDITIONS PREVAIL.  A MODERATE 1028 MB
HIGH PRESSURE IS CENTERED NEAR 34N40W AND IS PRODUCING TYPICAL
TRADEWIND EASTERLIES ACROSS THE ATLANTIC SOUTH OF 30N.  EXCEPT
FOR WEST OF 75W...SURFACE WINDS ARE LESS THAN 25 KT ACROSS THE
ATLANTIC.  A STRONG SAHARAN AIR LAYER...AS SHOWN BY THE CIMSS
SAL IMAGERY...CAN BE SEEN NORTH OF THE ITCZ AXIS EAST OF THE
PROMINENT WAVE AXIS AT 53W.  IN THE UPPER LEVELS...AN UPPER
LEVEL LOW IS AT 26N60W BUT THIS IS PRODUCING NO SIGNIFICANT DEEP
CONVECTION...NOR DOES IT HAVE ANY SURFACE COMPONENT.
ELSEWHERE...RIDGING EXTENDS IN THE UPPER LEVELS ALONG 8N ACROSS
THE ATLANTIC...WITH WESTERLY FLOW PREVAILING POLEWARD OF THIS
LATITUDE.

$$
LANDSEA




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