[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 131728
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SUN NOV 13 2005

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

...SPECIAL FEATURE...

A STRONG TROPICAL WAVE ALONG 60W/61W S OF 20N IS MOVING W ACROSS
THE LEEWARD AND WINDWARD ISLANDS AT 10 KT. A 1008 MB LOW IS
LOCATED ALONG THE WAVE VERY NEAR THE GRENADINES...OR NEAR
12.5N61W. SATELLITE IMAGERY SHOWS NEARLY ALL THE HEAVY TSTM
ACTIVITY STILL E OF THE ISLANDS...BUT THE LOW-LEVEL CIRCULATION
ASSOCIATED WITH THE WAVE/LOW IS OUTRUNNING THIS AREA AND IS
BEGINNING TO MOVE INTO THE FAR E CARIBBEAN. UPPER LEVEL WESTERLY
FLOW IS EMANATING FROM THE W/CNTRL CARIBBEAN AND INTERIOR SOUTH
AMERICA WITH A WEAK SHORTWAVE TROUGH ALONG 62W...AND THIS
CONTINUES TO PRODUCE STRONG WESTERLY SHEAR OVER THE SYSTEM WHICH
IS DISPLACING THE CONVECTION FARTHER E. SCATTERED MODERATE
CONVECTION IS FROM 10N-18N BETWEEN 51W-60W WITH ISOLATED SHOWERS
ALREADY MOVING ACROSS BARBADOS AND FROM MARTINIQUE NWD TO THE
ST. KITTS/ANTIGUA AREA. THE HEAVIEST CONVECTION IS EXPECTED TO
SPREAD OVER THE LESSER ANTILLES LATER TONIGHT WITH THE PATTERN
REMAINING UNSETTLED FOR MUCH OF THE UPCOMING WEEK. THE UPPER
LEVEL PATTERN MAY RELAX SOMEWHAT OVER THE SE CARIBBEAN DURING
THE NEXT FEW DAYS...POSSIBLY SUPPORTING TROPICAL DEVELOPMENT
WITHIN THE NEXT 36 HRS.

...TROPICAL WAVES...

SEE SPECIAL FEATURES FOR TROPICAL WAVE/LOW ALONG 60W/61W.

WEST/CENTRAL CARIBBEAN TROPICAL WAVE ALONG 78W S OF 16N MOVING W
10-15 KT. THE WAVE IS EMBEDDED WITHIN MODERATE/STRONG LOW-LEVEL
EASTERLY TRADES AND ACTUALLY APPEARS TO BE MOVING AWAY FROM THE
MOST INTENSE CONVECTION. ISOLATED SHOWERS/TSTMS ARE NEAR THE
AXIS FROM 10N-16N BETWEEN 76W-82W. SCATTERED MODERATE CONVECTION
IS WELL TO THE E FROM 11N-17N BETWEEN 67W-76W...AFFECTING THE
ABC ISLANDS AND THE CNTRL CARIBBEAN WATERS.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N10W 6N18W 6N30W 5N40W 13N58W...
THEN ALONG 10N61W 12N72W. WIDELY SCATTERED SHOWERS/TSTMS FROM
6N-12N BETWEEN 17W-22W. WIDELY SCATTERED MODERATE CONVECTION
WITHIN 60 NM OF THE AXIS BETWEEN 25W-50W.

...DISCUSSION...

GULF OF MEXICO...
SURFACE HIGH PRES CONTINUES TO PROGRESS EWD OVER THE W ATLC
WATERS AND IS LEAVING A TRAILING RIDGE ACROSS THE GULF FROM
GEORGIA/N FLORIDA TO VERACRUZ MEXICO. A BROAD UPPER TROUGH IS
SWINGING ACROSS THE NRN PLAINS AND GREAT LAKES...BUT IS SO FAR N
THAT THE FLOW OVER THE GULF IS MAINLY W/SW WITH CONTINUED
MODERATE/STRONG SUBSIDENCE. THE STRONGEST SUBSIDENCE IS WITHIN
350 NM OF AN UPPER HIGH LOCATED OVER WRN CUBA. AREAS OF CLOUDS
WITH ISOLATED SHOWERS LIE OVER THE N/CNTRL GULF N OF 25N BETWEEN
86W-92W AS MOISTURE GETS PULLED NWD AHEAD OF A COLD FRONT OVER
THE MID-MISSISSIPPI VALLEY. THIS FRONT IS EXPECTED TO STALL AND
MOVE BACK N BUT A STRONGER COLD FRONT WILL MOVE OFF THE TEXAS
COAST TUE EVENING/NIGHT WITH THE POTENTIAL FOR SHOWERS/TSTMS
OVER THE NW GULF SPREADING SE.

CARIBBEAN...
AN UPPER HIGH OVER WRN CUBA CONTINUES TO ADVECT DRY SUBSIDENT
AIR FROM THE BAHAMAS SWWD TOWARDS THE YUCATAN PENINSULA...WITH
THE BEST WEATHER ACROSS THE CARIBBEAN OCCURRING N OF 17N W OF
76W. THE SUBTROPICAL JET BEGINS NEAR NE HONDURAS AND EXTENDS NE
TO HISPANIOLA WITH PEAK WINDS NEAR 50-60 KT. DEEP MOISTURE LIES
S AND E OF THE JET AND IS PRODUCING TWO MAIN AREAS OF CLOUDS AND
DEEP CONVECTION. SEE SPECIAL FEATURES AND TROPICAL WAVES FOR
FURTHER DISCUSSION. THIS PATTERN IS EXPECTED TO REMAIN
ENTRENCHED FOR MUCH OF THE WEEK WITH THE CHANCE FOR AREAS OF
SHOWERS/TSTMS CONTINUING ESPECIALLY OVER THE SRN CARIBBEAN.

ATLANTIC...
FAIR WEATHER HAS TAKEN CONTROL OVER THE W ATLC WITH A BROKEN
STRATOCUMULUS FIELD ON THE S SIDE OF HIGH PRES WHICH IS CENTERED
ABOUT 275 NM E OF THE DELMARVA PENINSULA NEAR 37N69W. EXTENSIVE
DRY AIR IN THE MID/UPPER LEVELS HAS FILTERED IN OVER THE W
ATLC...BOUNDED BY THE SUBTROPICAL JET WHICH EXTENDS FROM HAITI
NEWD TO 25N60W 32N51W WITH MAXIMUM WINDS NEAR 70 KT. THE JET IS
NOW ALIGNED WITH THE FRONTAL BOUNDARY OVER THE AREA...MAKING IT
STATIONARY ALONG 20N73W 23N60W 26N55W...THEN AS A COLD FRONT
NEWD TO 32N49W. SCATTERED TO NUMEROUS MODERATE CONVECTION LIES E
OF THE COLD FRONT N OF 24N BETWEEN 45W-51W WHILE WIDELY
SCATTERED SHOWERS EXTEND ELSEWHERE WITHIN 90 NM OF THE BOUNDARY.
FARTHER S...A LARGE AREA OF BROAD UPPER DIFFLUENCE LIES E OF THE
LESSER ANTILLES AND IS SUPPORTING SCATTERED MODERATE CONVECTION
FROM 9N-19N BETWEEN 51W-58W...ASSOCIATED WITH THE TROPICAL WAVE
MOVING ACROSS THE ISLANDS. A LARGE AND COMPLEX UPPER LOW COVERS
MOST OF THE E/CNTRL ATLC CENTERED NEAR 24N28W AND MOVING SW 15
KT. THE LOW IS CAUSING THE SUBTROPICAL JET TO DIP SWD TO
10N...THEN SURGE BACK TO THE NE ACROSS THE CAPE VERDE ISLANDS
INTO WRN SAHARA. ISOLATED SHOWERS/TSTMS ARE NEAR THE UPPER LOW
FROM 18N-21N BETWEEN 29W-33W AND WIDESPREAD CIRRUS IS BEING
ADVECTED NEWD WITHIN 650 NM OF THE W AFRICAN COAST.

$$
BERG


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