[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 081801
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST THU MAR 08 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 8N13W 4N25W 2N40W TO THE COAST OF NE
BRAZIL NEAR EQ50W. SCATTERED CLUSTERS OF MODERATE CONVECTION ARE
FROM 2S-2N BETWEEN 27W-35W...WITHIN 30 NM OF THE AXIS BETWEEN
37W-40W...AND WITHIN 60 NM OF THE NE BRAZIL COAST FROM 3S-3N.

...DISCUSSION...

GULF OF MEXICO...
FAIRLY LIGHT WINDS AND LOW SEAS CONTINUE IN THE GULF THANKS TO A
WEAK SFC RIDGE THAT STRETCHES ACROSS THE AREA. PATCHES OF LOW TO
MID CLOUDS ARE SEEN N OF THE YUCATAN FROM 21N-28N BETWEEN
85W-90W...AND ALSO JUST OFFSHORE MEXICO/S TX S OF 27N. IN THE
UPPER LEVELS...THE FLOW IS MAINLY FROM THE WNW BENDING AROUND AN
UPPER RIDGE THAT EXTENDS NWD FROM THE TROPICAL EPAC INTO THE WRN
BAY OF CAMPECHE. SWLY FLOW ON THE W PERIPHERY OF THIS RIDGE IS
SPREADING HIGH LEVEL MOISTURE FROM THE EPAC INTO CENTRAL MEXICO
AND THROUGH THE GULF WATERS W OF 84W N OF 22N. MODESTLY DRY AIR
EXISTS ELSEWHERE AIDING IN THE OVERALL GOOD WEATHER ACROSS THE
BASIN. OVER THE NEXT COUPLE OF DAYS...LITTLE PATTERN CHANGE IS
ANTICIPATED BOTH AT THE SFC AND ALOFT KEEPING WINDS LIGHT AND
THE WEATHER CONDITIONS MAINLY FAIR ACROSS MOST OF THE AREA.

CARIBBEAN...
A WEAK SFC TROF HAS PERSISTED IN THE GULF OF HONDURAS EXTENDING
INLAND OVER NRN BELIZE. THE MAIN EFFECT OF THIS WEAK SYSTEM IS
AN AREA OF LOW TO MID LEVEL CLOUDS WITH EMBEDDED SHOWERS WHICH
LIE ACROSS NRN CENTRAL AMERICA AND THE COASTAL WATERS FROM
15N-22N W OF 84W. ELSEWHERE FAIRLY TYPICAL CONDITIONS EXIST WITH
MODERATE TO FRESH ELY TRADES AND THIN PATCHES OF LOW-LEVEL
MOISTURE STREAMING W ACROSS THE SEA. ALOFT...THERE IS SLIGHT
TROUGHING EXTENDING SWWD FROM ATLC ACROSS HISPANIOLA TO 12N80W.
THIS TROUGH IS ENHANCING THE WIDESPREAD DRY STABLE AIR
PREVENTING THE MOISTURE PATCHES FROM ACQUIRING MUCH VERTICAL
DEPTH. THE WEAK SFC TROUGH IN THE NW PORTION WILL CONTINUE
DRIFTING SLOWLY W WHILE WEAKENING. HOWEVER...GFS SUGGESTS THE
REMNANT MOISTURE WILL LINGER OVER THE YUCATAN PENINSULA AND
ADJACENT AREA THE NEXT COUPLE OF DAYS AS MOIST ONSHORE FLOW
PERSISTS. ELSEWHERE...SIMILAR TRADEWIND WEATHER WILL PERSIST.

WESTERN ATLANTIC...
SLIGHT MID TO UPPER LEVEL TROUGHING COVERS THE MAJORITY OF THE
ATLC W OF 55W EXTENDING SWD FROM A LARGE STRONG POLAR LOW. AN
ASSOCIATED WEAKENING FRONTAL BOUNDARY IS LINGERING IN THE REGION
ANALYZED STATIONARY ALONG 32N45W 25N58W THEN DISSIPATING TO
26N66W. BROKEN TO OVERCAST LOW AND MID LEVEL CLOUDS WITH
EMBEDDED ISOLATED SHOWERS ARE WITHIN 180 NM BEHIND THE
FRONT...WITH AN EMBEDDED AREA OF MODERATE CONVECTION WITH
POSSIBLE TSTMS FROM 25N-28N BETWEEN 64W-69W. A SFC TROUGH
REMAINS DRAPED THROUGH THE BAHAMAS AND ADJACENT ATLC WATERS
ALONG 30N75W 25N76W 21N74W. THIS MORNINGS QUIKSCAT DEPICTED THIS
BOUNDARY WELL. ASSOCIATED SCATTERED MODERATE CONVECTION IS FROM
22N-27N BETWEEN 72W-76W. THIS TROUGH IS LIKELY A RESULT OF
ENERGY THAT BROKE OFF FROM THE WEAKENING FRONT TO THE E AND
ENHANCED BY AN UPPER SHORTWAVE. LOOKING AHEAD A COUPLE OF
DAYS...MAIN FOCUS WILL BE THE SFC TROUGH IN THE BAHAMAS WHICH IS
EXPECTED TO DRIFT SLOWLY E TO NE. THIS WILL LIKELY CONTINUE TO
PRODUCE SOME UNSETTLED WEATHER FOR PORTIONS OF THE W
ATLC...ALONG WITH A POTENTIAL PROLONGED ELY SWELL EVENT FOR THE
SE U.S. COAST AS THE TROUGH INTERACTS WITH HI PRES TO ITS NORTH.

EASTERN ATLANTIC...
A STRONG 1035 MB HIGH PRES SYSTEM LOCATED BETWEEN PORTUGAL AND
THE AZORES IS DOMINATING THE SFC PATTERN ACROSS THE ATLC E OF
45W. THIS HIGH IS PRODUCING MODERATE TO STRONG TRADE WINDS
ACROSS A GOOD PORTION OF THE DISCUSSION AREA PARTICULARLY E OF
30W WHERE TIGHTEST PRES GRAD EXISTS. THE ONCE VIGOROUS UPPER LOW
HAS OPENED INTO A WEAKENING TROUGH ALIGNED ALONG 33W N OF 15N.
SWLY UPPER LEVEL FLOW AND DIFFLUENCE TO THE E OF THE TROUGH AXIS
IS STILL GENERATING PATCHY MID-HIGH LEVEL MOISTURE FROM 16N TO
BEYOND 32N BETWEEN 20W-34W. THIS MOISTURE PLUME IS SUBSTANTIALLY
THINNER THAN IT WAS YESTERDAY AT THIS TIME AND THIS TREND IS
EXPECTED TO CONTINUE AS THE TROUGH PULLS NWD AND DISSIPATES
LATER TODAY OR FRI. FAIR WEATHER LOOKS TO BE THE THEME FOR MOST
OF THE REGION THIS WEEKEND AS STRONG DEEP LAYER RIDGING BECOMES
WELL ESTABLISHED.

$$
WILLIS




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