[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 012156 RRA
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST FRI DEC 01 2006

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
1745 UTC.

TROPICAL WAVES...
TROPICAL WAVE IS ALONG 51W/52W S OF 16N MOVING W 10-15 KT. SOME
CYCLONIC TURNING IN THE LOWER CLOUD FIELD IS EVIDENT NEAR THE
WAVE. HOWEVER...IT IS NOT CLEAR CUT WITH OTHER SOURCES OF LOW
LEVEL VORTICITY NEARBY...SUCH AS THE STATIONARY FRONT TO THE
NE...THE ITCZ...AND SOME WEAK CONFLUENCE TO THE NW OF THE WAVE.
REGARDLESS...DEEP CONVECTION REMAINS MINIMAL WITH STIFF UPPER
WLY FLOW OVER THE AREA.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N12W 4N30W 8N50W 6N59W. DEEP
CONVECTION IS MINIMAL WITHIN SEVERAL HUNDRED NM OF THE AXIS
BETWEEN AFRICA AND 40W. A FEW CLUSTERS OF SCATTERED MODERATE
NOTED WITHIN 120 NM N OF THE AXIS BETWEEN 40W-46W.

...DISCUSSION...
GULF OF MEXICO...
EXTENSIVE SW FLOW ALOFT DOMINATING THE GULF BETWEEN THE UPPER
HIGH OVER THE NW CARIBBEAN AND UPPER TROUGHING OVER MUCH OF THE
US. THE STRONG COLD FRONT THAT HAS PUSHED INTO THE GULF HAS
SLOWED DOWN A BIT..AND AS OF 1500 UTC...EXTENDS FROM NEAR
VALDOSTA GEORGIA TO THE ERN BAY OF CAMPECHE. SCATTERED MODERATE
CONVECTION NOTED AHEAD OF THE FRONT FROM 24N-28N BETWEEN
83W-87W...WHICH IS ALSO ABOUT 100 NM W OF THE FLORIDA PENINSULA.
ISOLATED SHOWERS/TSTMS NOTED ELSEWHERE AHEAD OF THE FRONT IN THE
SE GULF. EXTENSIVE COLD AIR STRATOCUMULUS EXIST IN WAKE OF THE
FRONT. A GALE WARNING REMAINS IN EFFECT FOR THE SW GULF S OF 21N
AS STRONG 1031 MB HIGH PRESSURE BUILDS INTO THE REGION FROM SE
TEXAS. QUIKSCAT PASS THIS MORNING REVEALED A SOLID GALE EVENT
OCCURRING IN THE AREA BEHIND THE FRONT WITH ONE 50 KT VECTOR
EVEN NOTED. ANOTHER INTERESTING BYPRODUCT OF THIS FRONTAL SYSTEM
WAS SEAS JUMPED FROM 4 FT TO 18 FT AT BUOY 42002 LAST NIGHT IN 5
HOURS...WHICH WAS UNDERDONE BY ABOUT 4 FT BY WW3...AND ALSO
OCCURRED EARLIER THAN EXPECTED. EITHER WAY...THE EVENT IS NOW
RELAXING FROM N TO S. WINDS AND SEAS WILL SUBSIDE FURTHER INTO
SAT AS THE FRONT STALLS BETWEEN CENTRAL FLORIDA AND THE YUCATAN.
A SMALL WNW/NW SWELL FROM THE FRONT WILL ALSO SPREAD INTO W
FLORIDA THROUGH SAT.

CARIBBEAN SEA...
DEEP CONVECTION IN THE CARIBBEAN REMAINS LIMITED TO THE WRN
PORTION...WHERE CLUSTERS OF SCATTERED MODERATE CONVECTION NOTED
FROM 9N-20N BETWEEN 78W-86W. THIS SEEMS ASSOCIATED WITH LOW
LEVEL SPEED CONVERGENCE DOWNSTREAM OF THE STRONG ATLC SFC HIGH
NE OF THE AREA. ASSOCIATED HIGH CLOUDS/MOISTURE OVER THE
CONVECTION SEEN STREAMING ANTICYCLONICALLY AROUND THE UPPER HIGH
IN THE NW CARIBBEAN. AN UPPER TROUGH FROM THE CENTRAL ATLC IS
EXTENDING INTO THE ERN CARIBBEAN. SUBSTANTIAL DRY AIR ALOFT
NOTED IN WV IMAGERY IN THE CARIBBEAN WATERS BETWEEN THE WINDWARD
ISLANDS AND 77W. 1035 MB HIGH PRES OVER THE CENTRAL ATLC IS
MAINTAINING STRONG TO NEAR GALE FORCE WINDS OVER MOST OF THE
CARIBBEAN BASIN. WINDS AND SEAS WILL GRADUALLY DECREASE THROUGH
THE WEEKEND AS THE HIGH WEAKENS AND SHIFTS E.

ATLANTIC OCEAN...
FAIRLY AMPLIFIED RIDGE/TROUGH/RIDGE PATTERN CONTINUES TO
DOMINATE MUCH OF THE ATLC AREA. DRY MID TO UPPER AIR DOMINATES
THE WRN ATLC W OF 55W...ASIDE FROM SOME HIGH MOISTURE AND A FEW
ISOLATED SHOWERS OFF THE FL COAST AHEAD OF AN APPROACHING COLD
FRONT. STRONG SFC HIGH PRESSURE ALSO DOMINATING MUCH OF THE
CENTRAL AND SW NORTH ATLC...WITH A 1036 MB CENTER JUST N OF THE
AREA NEAR 36N45W. THIS CONTINUES TO PRODUCE STRONG TO NEAR GALE
FORCE ELY WINDS OVER THE WATERS E OF THE SRN BAHAMAS TO NEAR
30W. WINDS AND SEAS WILL GRADUALLY DIMINISH THIS WEEKEND AHEAD
OF A COLD FRONT THAT WILL PUSH OFF THE E COAST SAT...BECOMING
STATIONARY FROM 31N76W TO 30N81W BY LATE SAT. UPPER LOW SEEN
SPINNING NEAR 25N51W...THAT HAS A TROUGH EXTENDING SW THROUGH
THE LEEWARD ISLANDS. ASSOCIATED STATIONARY FRONT IS ALONG 32N23W
21N40W. ABUNDANT MOISTURE WITH SCATTERED SHOWERS WITH THESE
SYSTEMS FROM 20N-30N BETWEEN 32W-50W. ERN ATLC DOMINATED BY AN
UPPER HIGH JUST S OF THE CANARY ISLANDS. PERSISTENT WLY SHEAR
REMAINS OVER THE DEEP TROPICS AROUND AN UPPER RIDGE.

$$
WILLIS


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