[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 040545
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED JUN 03 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 40W/41W S OF 17N MOVING W 10 KT. THIS
WAVE IS HIGH AMPLITUDE FOR THIS TIME OF YEAR WITH A LARGE
INVERTED V SIGNATURE APPARENT IN THE STRATOCUMULUS CLOUDS AND AN
ASSOCIATED MOISTURE MAXIMUM NOTED IN THE TOTAL PRECIPITABLE
WATER PRODUCT. WHILE THE WAVE STRUCTURE IS WELL DEFINED...
CONVECTION IS ISOLATED MAINLY WITHIN 300 NM EITHER SIDE OF THE
WAVE AXIS S OF 10N.

A TROPICAL WAVE IS OVER THE SW CARIBBEAN ALONG 81W S OF 17N
MOVING W 15 KT. THIS WAVE HAS SLIGHT SIGNATURE IN THE LOW-LEVEL
CLOUDS...MORE SO TODAY THAN THE PAST FEW DAYS...BUT CONTINUES
TO  LACK DEEP MOISTURE. THE MAIN SENSIBLE WEATHER IMPACT IS THE
ENHANCED TRADES E OF THE WAVE AXIS.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N14W 6N21W 2N33W 1N43W AND
INTO NE BRAZIL NEAR 1N48W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS FROM 1N-4N BETWEEN 19W-22W AND FROM 1N-6N BETWEEN
23W-31W. SCATTERED MODERATE CONVECTION IS S OF 3N BETWEEN
43W-50W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH OVER THE WRN GULF ALONG 93W/94W IS SUPPORTING A
COLD FRONT ALONG THE TEXAS COAST. SWLY UPPER FLOW E OF THE
TROUGH AXIS IS ADVECTING CONSIDERABLE MOISTURE E OF 90W.
HOWEVER...ONLY ISOLATED SHOWERS AND TSTMS ARE EMBEDDED IN THIS
MOISTURE PLUME AT THE MOMENT. ADDITIONALLY...SHALLOW SHOWERS ARE
MOVING THROUGH FL STRAITS DRIVEN BY LOW-LEVEL ELY FLOW. SIMILAR
ACTIVITY IS OCCURRING OVER THE NW GULF ALONG THE UPPER TROUGH
AXIS...ENHANCED BY LOW-LEVEL CONVERGENCE ALONG THE FRONT
AND A PREFRONTAL TROUGH THAT EXTENDS FROM NEAR BATON ROUGE TO
28N94W. THIS FRONT IS FORECAST TO ENTER THE NW GULF OVER THE
NEXT FEW HOURS THEN CONTINUE EASTWARD INTO THE WEEKEND. SHOWERS
AND TSTMS ARE LIKELY TO CONTINUE ACROSS THE GULF THROUGHOUT THE
DAY AS THE UPPER TROUGH SLOWLY SHIFTS E. MODELS ARE IN FAIR
AGREEMENT IN SHOWING THE TROUGH CUT OFF OVER THE E GULF BY FRI
AND SAT...BRINGING THE GREATEST CHANCE OF TSTMS TO THE FAR E
WATERS.

CARIBBEAN SEA...
THE MID AND UPPER PATTERN CONTINUES TO FLATTEN AND IS NOW NEARLY
ZONAL. STRONG W-NW FLOW ALOFT IS TRANSPORTING MOISTURE N OF 18N.
THIS MOISTENED ENVIRONMENT COMBINED WITH A WEAK LOW-LEVEL TROUGH
OVER THE NRN LEEWARD ISLANDS IS GENERATING SCATTERED SHOWERS AND
TSTMS OVER THE LEEWARD ISLANDS...VIRGIN ISLANDS...PUERTO
RICO...AND HISPANIOLA. SCATTERED SHOWERS AND TSTMS ARE ALSO
POSSIBLE OVER THE YUCATAN PENINSULA ASSOCIATED WITH AN UPPER
TROUGH OVER THE GULF OF MEXICO. TRADE WINDS REMAIN 20-30 KT
ACROSS THE S CENTRAL PORTION DUE TO THE PRESSURE GRADIENT
BETWEEN A HIGH OVER THE SUBTROPICAL CENTRAL ATLC AND LOWER PRES
OVER NRN SOUTH AMERICA. E WINDS OCCASIONALLY NEAR 20 KT EXIST
OVER THE TOPOGRAPHICALLY ENHANCED GULF OF HONDURAS. LITTLE
CHANGE IN THESE FLOWS ARE FORECAST OVER THE NEXT COUPLE OF
DAYS.

ATLANTIC OCEAN...
WEATHER CONDITIONS ACROSS MUCH OF THE ATLC DISCUSSION ZONE
REMAIN QUIET...WITH ONLY A FEW AREAS OF UNSETTLED WEATHER TO
NOTE. ISOLATED SHOWERS AND TSTMS ARE S OF 23N W OF 60W...
INCLUDING THE SRN BAHAMAS...ASSOCIATED WITH AN UPPER JET...A
WEAK LOW-LEVEL TROUGH OVER THE NRN LEEWARDS...AND THE REMNANTS
OF A LOW-LEVEL E-W ORIENTED SHEAR AXIS. A LARGE SCALE DEEP LAYER
RIDGE DOMINATES THE CENTRAL ATLC...WITH A SERIES OF SFC HIGHS
SPREAD OUT ACROSS THE SUBTROPICS. A WEAK SURFACE TROUGH IS
ANALYZED FROM 30N33W TO 27N40W ONLY GENERATING SCATTERED SHOWERS
WITHIN 60 NM OF THE AXIS. THE E ATLC IS MAINLY UNDER AN UPPER
TROUGH WITH A DEEP LOW CENTERED SEVERAL HUNDRED NM N-NE OF THE
AZORES. WINDS ARE LIGHT ACROSS THE ENTIRE SUBTROPICS DUE TO THE
PRESENCE OF THE BROAD RIDGE. TRADE WINDS ARE GENERALLY 15-20 KT
ACROSS THE TROPICS. NLY WINDS ARE SLIGHTLY STRONGER NEAR THE
COAST OF AFRICA BETWEEN THE CAPE VERDE ISLANDS AND THE CANARY
ISLANDS DUE TO THE USUAL TIGHT PRESSURE GRADIENT BETWEEN THE
SUBTROPICAL RIDGING AND LOWER PRESSURE OVER AFRICA.

$$
CANGIALOSI



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