[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 061759
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN MAY 06 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND THE 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N12W 4N20W 1N30W EQ40W 1S48W. A
CLUSTER OF MODERATE TO STRONG CONVECTION CAME OFF THE AFRICAN
COAST EARLY THIS MORNING...BUT DURING THE LAST FEW HOURS THE
STRONGEST CONVECTION HAS DIMINISHED A BIT. IT COVERS FROM 2N-6N
BETWEEN 12W-16W. SCATTERED MODERATE CONVECTION IS WITHIN
30-45 NM EITHER SIDE OF THE AXIS WEST OF 39W.

...DISCUSSION...

GULF OF MEXICO...
MODERATE TO STRONG RETURN FLOW CONTINUES TO DOMINATE THE GULF
MAINLY W OF 90W WHERE A TIGHTER PRES GRADIENT EXISTS DUE TO
LOWER PRESSURE OVER MEXICO. EARLIER QUIKSCAT PASS SHOWED SLY
WINDS OF 15 TO 25 KT. AN UPPER RIDGE IS BUILDING ACROSS THE GULF
AND IS SPREADING UPPER LEVEL MOISTURE/HIGH CLOUDS EWD INTO THE
GULF ESPECIALLY W OF 90W. MOSTLY DRY MID TO UPPER AIR IS OVER
THE ERN PORTION WITH NW FLOW ASSOCIATED WITH A STRONG UPPER
TROUGH DIGGING OFF THE EASTERN SEABOARD. BACKDOOR FRONT
ASSOCIATED WITH THIS TROUGH WILL AFFECT THE MIDDLE AND ERN GULF
LATE TONIGHT INTO MON. STRONG HIGH PRES WILL FOLLOW THE FRONTAL
BOUNDARY GIVING THE AREA MODERATE TO STRONG NE-E FLOW. THIS
WINDS ARE EXPECTED TO INCREASE TO 20-25 KT LATE TONIGHT.

CARIBBEAN SEA...
LIGHT TO MODERATE TRADES ARE BLOWING ACROSS MUCH OF THE BASIN
DUE TO WEAK PRES GRADIENT OVER THE REGION. ALOFT...AN UPPER
TROUGH IS DIGGING INTO THE WESTERN CARIBBEAN...WHILE AN UPPER
HIGH CENTERED OFF NE SOUTH AMERICA  EXTENDS A BROAD RIDGE OVER
THE REMAINDER OF THE BASIN. THE RIDGE ALSO EXTENDS WWD FROM
VENEZUELA TO COSTA RICA. SWLY WINDS ON THE WESTERN PERIPHERY
OF THE RIDGE ARE TRANSPORTING ABUNDANT UPPER LEVEL MOISTURE/HIGH
CLOUDS FROM THE EPAC ITCZ LOCATED JUST SOUTH OF PANAMA/COSTA
RICA NEWD THROUGH THE CENTRAL AND NE CARIBBEAN. UPPER DIFFLUENCE
AND THE CLOSE PROXIMITY OF THE EPAC ITCZ ARE ENHANCING CLUSTERS
OF MODERATE TO ISOLATED STRONG CONVECTION OVER PANAMA...COSTA
RICA AND THE SW CARIBBEAN. FAIRLY WEAK PRES GRADIENT WILL KEEP
TRADES IN THE LIGHT TO MODERATE CATEGORY OVER THE NEXT COUPLE OF
DAYS.

ATLANTIC...
GLOBAL MODELS HAVE CONTINUED TO COME INTO BETTER AGREEMENT
REGARDING THE DEVELOPMENT AND ASSOCIATED FRONTAL STRUCTURE OF A
STRONG LOW PRESSURE CENTER OFF OF THE SE COAST OF UNITED
STATES LATER TODAY THROUGH TUESDAY. THIS IS EXPECTED TO BRING
SIGNIFICANT MARINE IMPACTS TO THE NW PORTION OF THE AREA INTO
EARLY NEXT WEEK...INCLUDING GALE FORCE WINDS AND LARGE NLY
SWELLS. SEVERAL MARINE ADVISORIES/WARNINGS ARE ALREADY IN EFFECT
ALONG THE EASTERN COAST OF U.S FROM SOUTH FLORIDA TO BEYOND THE
CAROLINAS. SHOWERS AND TSTMS HAVE INCREASED AHEAD OF THE
BACKDOOR FRONT CURRENTLY EXTENDING FROM A 1012 MB SFC LOW NEAR
THE OUTER BANK TO SOUTH GEORGIA. THIS CONVECTIVE ACTIVITY IS
MOVING SOUTH CLIPPING NE FLORIDA. A SFC TROUGH REMAINS OVER THE
W ATLC AND EXTENDS FROM 29N60W TO THE REGIONAL WATERS OF PUERTO
RICO. THIS TROUGH HAS A 1012 MB LOW ATTACHED NEAR 28N60W. LATEST
VIS SAT IMAGERY IS SHOWING A COUPLE OF LOW LEVEL SWIRLS ALONG
THE TROUGH AXIS. MOST OF THE SHOWER ACTIVITY REMAINS WITHIN 80
NM E OF THE TROUGH WHERE MORE UPPER SUPPORT EXISTS...WITH
DIFFLUENCE BETWEEN THE TROUGHING IN THE WRN ATLC AND RIDGING IN
THE CENTRAL ATLC.

MUCH OF THE REMAINDER OF THE ATLC DISCUSSION AREA IS DOMINATED
BY THE SRN PERIPHERY OF A QUASI-STATIONARY 1033MB SFC HIGH S OF
THE AZORES NEAR 35N28W. THIS IS GIVING THE AREA MODERATE TO
FRESH TRADES AND MOSTLY FAIR WEATHER WITH ONLY PATCHES OF LOW
LEVEL CLOUDS. THERE IS AN UPPER LOW NEAR 28N25W BUT IT DOES NOT
APPEAR TO BE GENERATING ANY SIGNIFICANT WEATHER.

$$
GR




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