[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 172353
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST FRI NOV 17 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE ALONG 52W S OF 21N IS NEARLY STATIONARY AS IT
APPROACHES A LARGE CUT OFF LOW CENTERED NEAR 25N57W. STRONG SWLY
UPPER LEVEL WINDS...ASSOCIATED WITH THIS CUT OFF LOW..IS
SHEARING ALL OF THE DEEP CLOUDINESS AND SHOWER ACTIVITY WELL TO
THE E/NE OF THE WAVE EXPOSING A SMALL ELONGATED LOW-LEVEL CLOUD
SWIRL ALONG THE AXIS NEAR 17N. SHOWERS AND TSTMS EXTEND FROM
12N-21N BETWEEN 46W-51W. THE UPPER LOW/WAVE INTERACTION IS
GENERATING MORE ACTIVITY FARTHER N...REFER TO THE ATLC
DISCUSSION FOR MORE DETAILS. THIS WAVE WILL BEGIN TO MOVE W
AGAIN AS IT BECOMES INCREASINGLY SHALLOW AND IS STEERED BY THE
LOW-LEVEL FLOW.

A TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN ALONG 70W S OF 20N
MOVING W 10 TO 15 KT. THIS WAVE IS VERY WEAK WITH ONLY A HINT OF
SOME CYCLONIC TURNING IN THE LOW-LEVEL CLOUDS. NO ORGANIZED
CLOUDINESS OR SHOWER ACTIVITY IS ASSOCIATED WITH THIS WAVE.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 11N15W 6N31W 6N51W 7N58W.
ISOLATED MODERATE IS WITHIN 180 NM EITHER SIDE OF THE AXIS
BETWEEN 25W-34W AND WITHIN 150 NM N OF THE AXIS BETWEEN
42W-48W.

...DISCUSSION...
THE GULF OF MEXICO...
PLENTY OF DRY STABLE AIR ALOFT ALONG WITH SFC HIGH PRES IS
PRODUCING FAIR AND PLEASANTLY COOL/DRY CONDITIONS WITH LIGHT
LOW-LEVEL WINDS ACROSS NEARLY THE ENTIRE GULF. HOWEVER...THE
EXTREME SRN GULF HAS NOT COMPLETELY CLEARED OUT AS A PLUME OF
MOISTURE IS ADVECTED ENE...FROM WEAKENING T.S. SERGIO AND THE
ITCZ IN THE EPAC...ACROSS SRN MEXICO TO EXTREME S FLORIDA. MOST
OF THIS MOISTURE IS MAINLY IN THE FORM OF MID-HIGH LEVEL
CLOUDINESS ALTHOUGH DOPPLER RADAR IS INDICATING SOME SHOWER
ACTIVITY IN THE FL STRAITS. THIS MOISTURE IS SLOWLY SEEPING SE
AND WILL LIKELY CLEAR THE AREA BY EARLY TOMORROW. FAIR AND COOL
CONDITIONS ARE EXPECTED TO CONTINUE THIS WEEKEND AS STABLE AIR
ALOFT REMAINS IN PLACE AND STRONG SFC HIGH PRES BUILDS INTO THE
CNTRL U.S. THE BUILDING OF THIS STRONG RIDGE WILL LIKELY
INCREASE THE WINDS/SEAS IN THE GULF THIS WEEKEND AND ESPECIALLY
EARLY NEXT WEEK.

THE CARIBBEAN SEA...
THE TAIL END OF AN ATLC FRONTAL BOUNDARY HAS BECOME STATIONARY
FROM CENTRAL CUBA TO THE NW COAST OF HONDURAS. LOW-LEVEL LIFT
NEAR THE BOUNDARY ALONG WITH UPPER DIFFLUENCE BETWEEN AN UPPER
HIGH NEAR 13N83W AND THE BASE OF THE TROUGH IN THE GULF IS
PRODUCING A FAIR AMOUNT OF MOISTURE IN THE WRN CARIBBEAN.
SCATTERED SHOWERS AND TSTMS ARE EMBEDDED IN THIS MOISTURE FROM
16N-21N BETWEEN 81W-86W AND IN THE SW CARIBBEAN FROM 12N-16N
BETWEEN 77W-83W. THE CENTRAL AND ERN CARIBBEAN IS QUIET WITH
STABLE AIR ALOFT...ESPECIALLY THE ERN CARIB...ON THE TYPICAL DRY
W SIDE OF THE UPPER LOW IN THE CENTRAL ATLC. THIS STABLE AIR IS
SUPPRESSING ANY SIGNIFICANT CONVECTION FROM FORMING. TRADE WINDS
ARE LIGHT ACROSS THE AREA...EXCEPT FOR STRONGER 15-20 KT N TO NE
WINDS BEHIND THE FRONT. NO BIG CHANGES ARE EXPECTED TOMORROW.
THEREAFTER WINDS AND SEAS ARE LIKELY TO INCREASE IN THE W CARIB
IN RESPONSE TO A REINFORCING COLD FRONT MOVING THROUGH THE GULF
OF MEXICO AND STRONG SFC HIGH PRES BEHIND IT.

THE ATLANTIC OCEAN...
A LARGE AMPLITUDE MID/UPPER LEVEL PATTERN IS ESTABLISHED ACROSS
THE WRN AND PART OF THE CNTRL ATLC. THE BASE OF A BROAD UPPER
TROUGH EXTENDS ACROSS THE ERN GULF AND THE SW ATLC. AN
ASSOCIATED COLD FRONT STRETCHES FROM 32N72W ACROSS THE WRN
BAHAMAS AND CENTRAL CUBA. INSTABILITY ASSOCIATED WITH THE SFC
BOUNDARY ALONG WITH UPPER DIFFLUENT AIR BETWEEN THE TROUGH
MENTIONED AND NARROW SLIGHT RIDGING TO THE E IS GENERATING AN
ABUNDANT AMOUNT OF MOISTURE BETWEEN 68W-80W EXCEPT NW OF A LINE
FROM S FL TO 32N73W WHERE THE DRY AIR HAS WORKED ITS WAY IN.
THIS MOISTURE DOES NOT APPEAR VERY DEEP IN NATURE...BASED ON IR
IMAGERY...WITH ONLY SCATTERED SHOWERS EMBEDDED. A LARGE CUT OFF
UPPER LOW IS CENTERED NEAR 27N56W. VERY DRY AIR LIES TO THE W
AND S OF THE UPPER LOW EXTENDING INTO THE ERN CARIBBEAN. A LARGE
AREA OF SCATTERED SHOWERS AND TSTMS EXISTS FROM 12N-32N BETWEEN
42W-55W ASSOCIATED WITH MOIST SLY UPPER LEVEL FLOW TO THE E OF
THE LOW AND ENHANCED BY A TROPICAL WAVE ALONG 52W. A SMALL 1012
MB LOW IS LOCATED TO THE W OF THE LARGE AREA OF UNSETTLED
WEATHER NEAR 29N58W PRODUCING ISOLATED SHOWERS WITHIN 300 NM OF
ITS CENTER. THE FLOW THEN BECOMES FAIRLY ZONAL E OF 40W BETWEEN
SLIGHT RIDGING IN THE TROPICS AND SLIGHT TROUGHING IN THE
SUBTROPICS. SFC RIDGING IS WELL ESTABLISHED IN THE CNTRL AND ERN
ATLC HELPING TO PRODUCE FAIR WEATHER E OF 40W.

$$
CANGIALOSI


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