[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 280528
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST TUE NOV 28 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...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0500 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 9N13W 6N30W 4N41W 3N55W. THE ITCZ IS
RATHER QUIET WITH ONLY A COUPLE SMALL PATCHES OF SCATTERED
MODERATE CONVECTION WITHIN 90 NM EITHER SIDE BETWEEN 23W-29W AND
32W-40W.

...DISCUSSION...
THE GULF OF MEXICO...
THE WEATHER ACROSS THE GULF HAS CHANGED LITTLE OVER THE PAST FEW
DAYS AS SFC HIGH PRES CONTINUES TO DOMINATE THE AREA. BREEZY
15-20 KT ELY WINDS IN THE ERN AND CNTRL GULF IS ADVECTING
PATCHES OF LOW-LEVEL CLOUDS AND EMBEDDED ISOLATED TO SCATTERED
SHOWERS ACROSS CENTRAL AND SOUTH FLORIDA ON THE BREEZE. SOME OF
THIS LOW-LEVEL MOISTURE IS BEING DRIVEN ACROSS THE GULF AND
TOWARDS THE SE TEXAS COAST BY SELY RETURN FLOW AROUND THE 1028
MB SFC HIGH CENTERED IN MID-ATLANTIC STATES. IN THE UPPER
LEVELS...A PRONOUNCED RIDGE IS CENTERED IN THE S CENTRAL GULF
NEAR 23N91W WITH RIDGING EXTENDING ACROSS THE FL PANHANDLE AND
INTO THE OHIO VALLEY. WIDESPREAD STRONG SUBSIDENCE EXISTS
EVERYWHERE ABOVE THE GULF. THIS STRONG CAP IS PREVENTING THE
LOW-LAYER OF MOISTURE TO ACQUIRE MUCH DEPTH. GFS SHOWS THE SFC
AND UPPER RIDGE SLIDING E IN RESPONSE TO AN UPPER TROUGH
CURRENTLY OVER THE WRN U.S. THIS WILL ALLOW TEMPS TO REMAIN
SLIGHTLY ABOVE NORMAL VALUES OVER THE NEXT COUPLE DAYS BEFORE A
STRONG COLD FRONT MOVES OFF THE TX COAST LATE THU.

THE CARIBBEAN SEA...
A WELL-DEFINED HIGHLY ELONGATED UPPER LEVEL TROUGH STRETCHES
ACROSS THE WINDWARD PASSAGE TO NEAR 18N82W. THE TAIL END OF AN
ASSOCIATED COLD FRONT REACHES THE ERN END OF THE DOMINICAN
REPUBLIC. MULTILAYER CLOUDINESS AND SCATTERED SHOWERS ASSOCIATED
WITH THE TROUGH/FRONT IS CONTAINED N OF 18N BETWEEN 65W-71W. A
VERY BROAD FLATTENING UPPER LEVEL RIDGE LIES S AND E OF THE
TROUGH CENTERED OVER VENEZUELA. S-SWLY UPPER LEVEL FLOW ON THE W
SIDE OF THE BROAD RIDGE AXIS IS DRAWING SOME MOISTURE FROM THE
ITCZ. UPPER DIFFLUENCE IS PRODUCING SCATTERED SHOWERS AND TSTMS
S OF 15N BETWEEN 80W-84W. THE REMAINDER OF THE CARIB IS QUIET
WITH VERY DRY AIR/STRONG SUBSIDENCE ABOVE THE NW CARIB AND
MODERATELY DRY AIR ALOFT ELSEWHERE. THIS DRY AIR IS SUPPRESSING
ANY DEEP CLOUDINESS IN THE AREAS NOT OUTLINED. TRADES ARE
MODERATE AND WILL LIKELY REMAIN THAT WAY OVER THE NEXT DAY OR
TWO. LATER THIS WEEK...THESE WINDS WILL LIKELY INCREASE AS THE
FRONTAL BOUNDARY PULLS NE AND STRONG HIGH PRES DEVELOPS TO THE N
TIGHTENING THE PRES GRAD.

THE ATLANTIC OCEAN...
VERY DRY AIR ALOFT...PRODUCED BY UPPER LEVEL CONFLUENCE BETWEEN
A WELL-DEFINED UPPER TROUGH ALONG 32N57W 25N66W TO THE WINDWARD
PASSAGE AND UPPER HIGH IN THE GULF...AND PATCHES OF LOW-LEVEL
MOISTURE UNDERNEATH THE STRONG MID-LEVEL CAP COVERS MUCH OF THE
WRN ATLC BEHIND A COLD FRONT. THE FRONT IS IN THE CENTRAL ATLC
AND EXTENDS FROM AN OCCLUDED 1007 MB LOW NEAR 34N50W ALONG
24N56W 20N63W TO THE MONA PASSAGE. SWLY UPPER LEVEL FLOW ON THE
E SIDE OF THE MID/UPPER LEVEL TROUGH AXIS AND LOW-LEVEL LIFT
NEAR THE SFC BOUNDARY IS PRODUCING MULTILAYERED CLOUDS WITH
EMBEDDED SCATTERED SHOWERS WITHIN 240 NM EITHER SIDE OF THE
FRONT. MODELS SHOW THE SFC LOW QUICKLY RACING TO THE NE WHICH
SHOULD HELP TO SLOWLY THIN THE MOISTURE IN THIS AREA OVER THE
NEXT DAY OR TWO. AN ELONGATED LOW AMPLITUDE MID/UPPER RIDGE LIES
E OF THE TROUGH AND COVERS THE AREA BETWEEN 25W-50W. DEEP
MOISTURE IS VERY LIMITED IN THE E ATLC INCLUDING THE ITCZ WHICH
LOOKS PARTICULARLY QUIET THIS MORNING. PLENTY OF DRY STABLE AIR
ALOFT IS LOCATED E OF 25W ENHANCED BY UPPER LEVEL CONFLUENT FLOW
W OF AN UPPER TROUGH JUST W OF AFRICA. AT THE SFC...WEAK TO
MODERATE HIGH PRES RIDGING IS THE RULE ACROSS THE ERN AND WRN
SUBTROPICAL ATLC SUPPORTED BY A 1026 MB HIGH NEAR THE AZORES AND
A 1028 MB HIGH IN THE MID-ATLANTIC U.S. A PRONOUNCED WEAKNESS IN
THIS RIDGING LIES IN THE CNTRL ATLC DUE TO THE LOW/FRONTAL
BOUNDARY MENTIONED.

$$
CANGIALOSI


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